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Bibliography on: Evolution of Multicelluarity

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Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 26 May 2019 at 01:32 Created: 

Evolution of Multicelluarity

Created with PubMed® Query: (evolution OR origin) AND (multicellularity OR multicellular) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2019-05-23

Liu T, Wang X, Wang G, et al (2019)

Evolution of Complex Thallus Alga: Genome Sequencing of Saccharina japonica.

Frontiers in genetics, 10:378.

Saccharina, as one of the most important brown algae (Phaeophyceae) with multicellular thallus, has a very remarkable evolutionary history, and globally accounts for most of the economic marine aquaculture production worldwide. Here, we present the 580.5 million base pairs of genome sequence of Saccharina japonica, whose current assembly contains 35,725 protein-coding genes. In a comparative analysis with Ectocarpus siliculosus, the integrated virus sequence suggested the genome evolutionary footprints, which derived from their co-ancestry and experienced genomic arrangements. Furthermore, the gene expansion was found to be an important strategy for functional evolution, especially with regard to extracelluar components, stress-related genes, and vanadium-dependent haloperoxidases, and we proposed a hypothesis that gene duplication events were the main driving force for the evolution history from multicellular filamentous algae to thallus algae. The sequenced Saccharina genome paves the way for further molecular studies and is useful for genome-assisted breeding of S. japonica and other related algae species.

RevDate: 2019-05-23

Loron CC, François C, Rainbird RH, et al (2019)

Early fungi from the Proterozoic era in Arctic Canada.

Nature pii:10.1038/s41586-019-1217-0 [Epub ahead of print].

Fungi are crucial components of modern ecosystems. They may have had an important role in the colonization of land by eukaryotes, and in the appearance and success of land plants and metazoans1-3. Nevertheless, fossils that can unambiguously be identified as fungi are absent from the fossil record until the middle of the Palaeozoic era4,5. Here we show, using morphological, ultrastructural and spectroscopic analyses, that multicellular organic-walled microfossils preserved in shale of the Grassy Bay Formation (Shaler Supergroup, Arctic Canada), which dates to approximately 1,010-890 million years ago, have a fungal affinity. These microfossils are more than half a billion years older than previously reported unambiguous occurrences of fungi, a date which is consistent with data from molecular clocks for the emergence of this clade6,7. In extending the fossil record of the fungi, this finding also pushes back the minimum date for the appearance of eukaryotic crown group Opisthokonta, which comprises metazoans, fungi and their protist relatives8,9.

RevDate: 2019-05-22

Ballinger MJ, SJ Perlman (2019)

The defensive Spiroplasma.

Current opinion in insect science, 32:36-41.

Defensive microbes are of great interest for their roles in arthropod health, disease transmission, and biocontrol efforts. Obligate bacterial passengers of arthropods, such as Spiroplasma, confer protection against the natural enemies of their hosts to improve their own fitness. Although known for less than a decade, Spiroplasma's defensive reach extends to diverse parasites, both microbial and multicellular. We provide an overview of known defensive phenotypes against nematodes, parasitoid wasps, and fungi, and highlight recent studies supporting the role of Spiroplasma-encoded ribosome-inactivating proteins in protection. With cellular features well-suited for life in the hemolymph, broad distribution among invertebrate hosts, and the capacity to repeatedly evolve vertical transmission, Spiroplasma may be uniquely equipped to form intimate, defensive associations to combat extracellular parasites. Along with insights into defensive mechanisms, recent significant advances have been made in male-killing - a phenotype with interesting evolutionary ties to defense. Finally, we look forward to an exciting decade using the genetic tools of Drosophila, and the rapidly-advancing tractability of Spiroplasma itself, to better understand mechanisms and evolution in defensive symbiosis.

RevDate: 2019-05-20
CmpDate: 2019-05-20

Nakahara N, Nobu MK, Takaki Y, et al (2019)

Aggregatilinea lenta gen. nov., sp. nov., a slow-growing, facultatively anaerobic bacterium isolated from subseafloor sediment, and proposal of the new order Aggregatilineales ord. nov. within the class Anaerolineae of the phylum Chloroflexi.

International journal of systematic and evolutionary microbiology, 69(4):1185-1194.

A novel slow-growing, facultatively anaerobic, filamentous bacterium, strain MO-CFX2T, was isolated from a methanogenic microbial community in a continuous-flow bioreactor that was established from subseafloor sediment collected off the Shimokita Peninsula of Japan. Cells were multicellular filamentous, non-motile and Gram-stain-negative. The filaments were generally more than 20 µm (up to approximately 200 µm) long and 0.5-0.6 µm wide. Cells possessed pili-like structures on the cell surface and a multilayer structure in the cytoplasm. Growth of the strain was observed at 20-37 °C (optimum, 30 °C), pH 5.5-8.0 (pH 6.5-7.0), and 0-30 g l-1 NaCl (5 g l-1 NaCl). Under optimum growth conditions, doubling time and maximum cell density were estimated to be approximately 19 days and ~105 cells ml-1, respectively. Strain MO-CFX2T grew chemoorganotrophically on a limited range of organic substrates in anaerobic conditions. The major cellular fatty acids were saturated C16 : 0 (47.9 %) and C18 : 0 (36.9 %), and unsaturated C18 : 1ω9c (6.0 %) and C16 : 1ω7 (5.1 %). The G+C content of genomic DNA was 63.2 mol%. 16S rRNA gene-based phylogenetic analysis showed that strain MO-CFX2T shares a notably low sequence identity with its closest relatives, which were Thermanaerothrix daxensis GNS-1T and Thermomarinilinea lacunifontana SW7T (both 85.8 % sequence identity). Based on these phenotypic and genomic properties, we propose the name Aggregatilinea lenta gen. nov., sp. nov. for strain MO-CFX2T (=KCTC 15625T, =JCM 32065T). In addition, we also propose the associated family and order as Aggregatilineaceae fam. nov. and Aggregatilineales ord. nov., respectively.

RevDate: 2019-05-16

Khan MAW, Stephens WZ, Mohammed AD, et al (2019)

Does MHC heterozygosity influence microbiota form and function?.

PloS one, 14(5):e0215946 pii:PONE-D-18-12229.

MHC molecules are essential for the adaptive immune response, and they are the most polymorphic genetic loci in vertebrates. Extreme genetic variation at these loci is paradoxical given their central importance to host health. Classic models of MHC gene evolution center on antagonistic host-pathogen interactions to promote gene diversification and allelic diversity in host populations. However, all multicellular organisms are persistently colonized by their microbiota that perform essential metabolic functions for their host and protect from infection. Here, we provide data to support the hypothesis that MHC heterozygote advantage (a main force of selection thought to drive MHC gene evolution), may operate by enhancing fitness advantages conferred by the host's microbiome. We utilized fecal 16S rRNA gene sequences and their predicted metagenome datasets collected from multiple MHC congenic homozygote and heterozygote mouse strains to describe the influence of MHC heterozygosity on microbiome form and function. We find that in contrast to homozygosity at MHC loci, MHC heterozygosity promotes functional diversification of the microbiome, enhances microbial network connectivity, and results in enrichment for a variety of microbial functions that are positively associated with host fitness. We demonstrate that taxonomic and functional diversity of the microbiome is positively correlated in MHC heterozygote but not homozygote animals, suggesting that heterozygote microbiomes are more functionally adaptive under similar environmental conditions than homozygote microbiomes. Our data complement previous observations on the role of MHC polymorphism in sculpting microbiota composition, but also provide functional insights into how MHC heterozygosity may enhance host health by modulating microbiome form and function. We also provide evidence to support that MHC heterozygosity limits functional redundancy among commensal microbes and may enhance the metabolic versatility of their microbiome. Results from our analyses yield multiple testable predictions regarding the role of MHC heterozygosity on the microbiome that will help guide future research in the area of MHC-microbiome interactions.

RevDate: 2019-05-15

Pichugin Y, Park HJ, A Traulsen (2019)

Evolution of simple multicellular life cycles in dynamic environments.

Journal of the Royal Society, Interface, 16(154):20190054.

The mode of reproduction is a critical characteristic of any species, as it has a strong effect on its evolution. As any other trait, the reproduction mode is subject to natural selection and may adapt to the environment. When the environment varies over time, different reproduction modes could be optimal at different times. The natural response to a dynamic environment seems to be bet hedging, where multiple reproductive strategies are stochastically executed. Here, we develop a framework for the evolution of simple multicellular life cycles in a dynamic environment. We use a matrix population model of undifferentiated multicellular groups undergoing fragmentation and ask which mode maximizes the population growth rate. Counterintuitively, we find that natural selection in dynamic environments generally tends to promote deterministic, not stochastic, reproduction modes.

RevDate: 2019-05-15

Gao Y, Traulsen A, Y Pichugin (2019)

Interacting cells driving the evolution of multicellular life cycles.

PLoS computational biology, 15(5):e1006987 pii:PCOMPBIOL-D-19-00097 [Epub ahead of print].

Evolution of complex multicellular life began from the emergence of a life cycle involving the formation of cell clusters. The opportunity for cells to interact within clusters provided them with an advantage over unicellular life forms. However, what kind of interactions may lead to the evolution of multicellular life cycles? Here, we combine evolutionary game theory with a model for the emergence of multicellular groups to investigate how cell interactions can influence reproduction modes during the early stages of the evolution of multicellularity. In our model, the presence of both cell types is maintained by stochastic phenotype switching during cell division. We identify evolutionary optimal life cycles as those which maximize the population growth rate. Among all interactions captured by two-player games, the vast majority promotes two classes of life cycles: (i) splitting into unicellular propagules or (ii) fragmentation into two offspring clusters of equal (or almost equal) size. Our findings indicate that the three most important characteristics, determining whether multicellular life cycles will evolve, are the average performance of homogeneous groups, heterogeneous groups, and solitary cells.

RevDate: 2019-05-11

Vinogradov AE, OV Anatskaya (2019)

Evolutionary framework of human interactome: unicellular and multicellular giant clusters.

Bio Systems pii:S0303-2647(19)30010-3 [Epub ahead of print].

The main contradiction of multicellularity (MCM) is between the unicellular (UC) and multicellular (MC) levels. In human interactome we revealed two giant clusters with MC and UC medians (and several smaller ones with MC medians). The enrichment of these clusters by phylostrata and by functions support the MC versus UC division. The total interactome and the giant clusters show a core-periphery evolutionary growth. From viewpoint of the MCM, the most important is the placement of genes, appearing at UC evolutionary stage, in the MC clusters. Thus, genes involved in vesicle-mediated transport, cell cycle, cellular responses to stress, post-translational modifications and many diseases appeared at UC evolutionary stage but are placed mostly in MC clusters. Genes downregulated with age are enriched in UC cluster, whereas the upregulated genes are preferentially placed in MC giant cluster. The tumor suppressor and pluripotency regulating pathways are also enriched in MC giant cluster. Therefore, this cluster probably operates as 'internal manager' constraining runaway unicellularity. The clusters have denser interactions within than between them, therefore they can serve as attractors (stable states of dynamic systems) of cellular programs. Importantly, the UC cluster have a higher inside/outside connection ratio compared with MC clusters, which suggests a stronger attractor effect and may explain why cells of MC organisms are prone to oncogenesis. The evolutionary clustering of human interactome elucidates the MC control over functions appearing at UC evolutionary stage and can build a framework for biosystems studies focusing on the interplay between UC and MC levels.

RevDate: 2019-05-09

Erkenbrack EM, JR Thompson (2019)

Cell type phylogenetics informs the evolutionary origin of echinoderm larval skeletogenic cell identity.

Communications biology, 2:160 pii:417.

The multiplicity of cell types comprising multicellular organisms begs the question as to how cell type identities evolve over time. Cell type phylogenetics informs this question by comparing gene expression of homologous cell types in distantly related taxa. We employ this approach to inform the identity of larval skeletogenic cells of echinoderms, a clade for which there are phylogenetically diverse datasets of spatial gene expression patterns. We determined ancestral spatial expression patterns of alx1, ets1, tbr, erg, and vegfr, key components of the skeletogenic gene regulatory network driving identity of the larval skeletogenic cell. Here we show ancestral state reconstructions of spatial gene expression of extant eleutherozoan echinoderms support homology and common ancestry of echinoderm larval skeletogenic cells. We propose larval skeletogenic cells arose in the stem lineage of eleutherozoans during a cell type duplication event that heterochronically activated adult skeletogenic cells in a topographically distinct tissue in early development.

RevDate: 2019-05-09

Wang P, Liang J, Shi LZ, et al (2018)

Visualizing Spatiotemporal Dynamics of Intercellular Mechanotransmission upon Wounding.

ACS photonics, 5(9):3565-3574.

During cell-to-cell communications, the interplay between physical and biochemical cues is essential for informational exchange and functional coordination, especially in multicellular organisms. However, it remains a challenge to visualize intercellular signaling dynamics in single live cells. Here, we report a photonic approach, based on laser microscissors and Förster resonance energy transfer (FRET) microscopy, to study intercellular signaling transmission. First, using our high-throughput screening platform, we developed a highly sensitive FRET-based biosensor (SCAGE) for Src kinase, a key regulator of intercellular interactions and signaling cascades. Notably, SCAGE showed a more than 40-fold sensitivity enhancement than the original biosensor in live mammalian cells. Next, upon local severance of physical intercellular connections by femtosecond laser pulses, SCAGE enabled the visualization of a transient Src activation across neighboring cells. Lastly, we found that this observed transient Src activation following the loss of cell-cell contacts depends on the passive structural support of cytoskeleton but not on the active actomyosin contractility. Hence, by precisely introducing local physical perturbations and directly visualizing spatiotemporal transmission of ensuing signaling events, our integrated approach could be broadly applied to mimic and investigate the wounding process at single-cell resolutions. This integrated approach with highly sensitive FRET-based biosensors provides a unique system to advance our in-depth understanding of molecular mechanisms underlying the physical-biochemical basis of intercellular coupling and wounding processes.

RevDate: 2019-05-07

Turan ZG, Parvizi P, Dönertaş HM, et al (2019)

Molecular footprint of Medawar's mutation accumulation process in mammalian aging.

Aging cell [Epub ahead of print].

Medawar's mutation accumulation hypothesis explains aging by the declining force of natural selection with age: Slightly deleterious germline mutations expressed in old age can drift to fixation and thereby lead to aging-related phenotypes. Although widely cited, empirical evidence for this hypothesis has remained limited. Here, we test one of its predictions that genes relatively highly expressed in old adults should be under weaker purifying selection than genes relatively highly expressed in young adults. Combining 66 transcriptome datasets (including 16 tissues from five mammalian species) with sequence conservation estimates across mammals, here we report that the overall conservation level of expressed genes is lower at old age compared to young adulthood. This age-related decrease in transcriptome conservation (ADICT) is systematically observed in diverse mammalian tissues, including the brain, liver, lung, and artery, but not in others, most notably in the muscle and heart. Where observed, ADICT is driven partly by poorly conserved genes being up-regulated during aging. In general, the more often a gene is found up-regulated with age among tissues and species, the lower its evolutionary conservation. Poorly conserved and up-regulated genes have overlapping functional properties that include responses to age-associated tissue damage, such as apoptosis and inflammation. Meanwhile, these genes do not appear to be under positive selection. Hence, genes contributing to old age phenotypes are found to harbor an excess of slightly deleterious alleles, at least in certain tissues. This supports the notion that genetic drift shapes aging in multicellular organisms, consistent with Medawar's mutation accumulation hypothesis.

RevDate: 2019-05-05

Singer D, Mitchell EAD, Payne RJ, et al (2019)

Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists.

Molecular ecology [Epub ahead of print].

Recent studies show that soil eukaryotic diversity is immense and dominated by microorganisms. However, it is unclear to what extent the processes that shape the distribution of diversity in plants and animals also apply to microorganisms. Major diversification events in multicellular organisms have often been attributed to long-term climatic and geological processes, but the impact of such processes on protist diversity has received much less attention as their distribution has often been believed to be largely cosmopolitan. Here, we quantified phylogeographic patterns in Hyalosphenia papilio, a large testate amoeba restricted to Holarctic Sphagnum-dominated peatlands, to test if the current distribution of its genetic diversity can be explained by historical factors or by the current distribution of suitable habitat. Phylogenetic diversity was higher in Western North America, corresponding to the inferred geographical origin of the H. papilio complex, and was lower in Eurasia despite extensive suitable habitat. These results suggest that patterns of phylogenetic diversity and distribution can be explained by the history of Holarctic Sphagnum peatland range expansions and contractions in response to Quaternary glaciations that promoted cladogenetic range evolution, rather than the contemporary distribution of suitable habitats. Species distributions were positively correlated with climatic niche breadth, suggesting that climatic tolerance is key to dispersal ability in H. papilio. This implies that, at least for large and specialized terrestrial microorganisms, propagule dispersal is slow enough that historical processes may contribute to their diversification and phylogeographic patterns and may partly explain their very high overall diversity. This article is protected by copyright. All rights reserved.

RevDate: 2019-05-04

Li J, Zhang H, Liu P, et al (2019)

Phylogenetic and structural identification of a novel magnetotactic Deltaproteobacterium strain WYHR-1 from a freshwater lake.

Applied and environmental microbiology pii:AEM.00731-19 [Epub ahead of print].

Magnetotactic bacteria (MTB) are phylogenetically diverse prokaryotes that are able to biomineralize intracellular, magnetic chains of magnetite or greigite nanocrystals called magnetosomes. Simultaneous characterization of MTB phylogeny and biomineralization is crucial but challenging because most MTB are extremely difficult to culture. We identify a large rod, bean-like MTB (tentatively named WYHR-1) from freshwater sediments of Weiyang Lake, Xi'an, China, using a coupled fluorescence and scanning electron microscopy approach at the single-cell scale. Phylogenetic analysis of 16S rRNA gene sequences indicates that WYHR-1 is a novel genus from the Deltaproteobacteria class. Transmission electron microscope observations reveal that WYHR-1 cells contain tens of magnetite magnetosomes that are organized into a single chain bundle along the cell long axis. Mature WYHR-1 magnetosomes are bullet-shaped, straight and elongated along the (001) direction, with a large flat end terminated by a {100} face at the base and a conical top. This crystal morphology is distinctively different from bullet-shaped magnetosomes produced by other MTB in the Deltaproteobacteria class and the Nitrospirae phylum. This indicates that WYHR-1 may have a different crystal growth process and mechanism from other species, which results from species-specific magnetosome biomineralization in MTB.IMPORTANCE Magnetotactic bacteria (MTB) are a model system for understanding biomineralization, and are also studied intensively in biogeomagnetic and paleomagnetic research. However, many uncultured MTB strains have not been identified phylogenetically or investigated structurally at the single-cell level, which limits comprehensive understanding of MTB diversity and their role in biomineralization. We have identified a novel MTB strain WYHR-1 from a freshwater lake using a coupled fluorescence and scanning electron microscopy approach at the single-cell scale. Our analyses further indicate that strain WYHR-1 represents a novel genus from the Deltaproteobacteria class. In contrast to bullet-shaped magnetosomes produced by other MTB in the Deltaproteobacteria class and the Nitrospirae phylum, WYHR-1 magnetosomes are bullet-shaped, straight, and highly elongated along the (001) direction, and are terminated by a large {100} face at their base and have a conical top. Our findings imply that, consistent with phylogenetic diversity of MTB, bullet-shaped magnetosomes have diverse crystal habits and growth patterns.

RevDate: 2019-05-02

Biscotti MA, Barucca M, Carducci F, et al (2019)

The p53 gene family in vertebrates: Evolutionary considerations.

Journal of experimental zoology. Part B, Molecular and developmental evolution [Epub ahead of print].

The origin of the p53 gene family predates multicellular life since TP53 members of this gene family have been found in unicellular eukaryotes. In invertebrates one or two genes attributable to a TP53-like or TP63/73-like gene are present. The radiation into three genes, TP53, TP63, and TP73, has been reported as a vertebrate invention. TP53 is considered the "guardian of the genome" given its role in protecting cells against the DNA damage and cellular stressors. TP63 and TP73 play a role in epithelial development and neurogenesis, respectively. The evolution of the p53 gene family has been the subject of considerable analyses even if several questions remain still open. In this study we addressed the evolutionary history of the p53 gene family in vertebrates performing an extended microsyntenic investigation coupled with a phylogenetic analysis, together with protein domain organization and structure assessment. On the basis of our results we discussed a possible evolutionary scenario according to which a TP53/63/73 ancestor form gave rise to the current TP53 and a TP63/73 form, which in turn independently duplicated into two genes in agnathe and gnathostome lineages.

RevDate: 2019-05-01

Salvi M, Morbiducci U, Amadeo F, et al (2019)

Automated Segmentation of Fluorescence Microscopy Images for 3D Cell Detection in human-derived Cardiospheres.

Scientific reports, 9(1):6644 pii:10.1038/s41598-019-43137-2.

The 'cardiosphere' is a 3D cluster of cardiac progenitor cells recapitulating a stem cell niche-like microenvironment with a potential for disease and regeneration modelling of the failing human myocardium. In this multicellular 3D context, it is extremely important to decrypt the spatial distribution of cell markers for dissecting the evolution of cellular phenotypes by direct quantification of fluorescent signals in confocal microscopy. In this study, we present a fully automated method, named CARE ('CARdiosphere Evaluation'), for the segmentation of membranes and cell nuclei in human-derived cardiospheres. The proposed method is tested on twenty 3D-stacks of cardiospheres, for a total of 1160 images. Automatic results are compared with manual annotations and two open-source software designed for fluorescence microscopy. CARE performance was excellent in cardiospheres membrane segmentation and, in cell nuclei detection, the algorithm achieved the same performance as two expert operators. To the best of our knowledge, CARE is the first fully automated algorithm for segmentation inside in vitro 3D cell spheroids, including cardiospheres. The proposed approach will provide, in the future, automated quantitative analysis of markers distribution within the cardiac niche-like environment, enabling predictive associations between cell mechanical stresses and dynamic phenotypic changes.

RevDate: 2019-04-30

Borisenko I, Podgornaya OI, AV Ereskovsky (2019)

From traveler to homebody: Which signaling mechanisms sponge larvae use to become adult sponges?.

Advances in protein chemistry and structural biology, 116:421-449.

Cell-to-cell signaling is responsible for regulation of many developmental processes such as proliferation, cell migration, survival, cell fate specification and axis patterning. In this article we discussed the role of signaling in the metamorphosis of sponges with a focus on epithelial-mesenchymal transition (EMT) accompanying this event. Sponges (Porifera) are an ancient lineage of morphologically simple animals occupying a basal position on the tree of life. The study of these animals is necessary for understanding the origin of multicellularity and the evolution of developmental processes. Development of sponges is quite diverse. It finishes with the metamorphosis of a free-swimming larva into a young settled sponge. The outer surface of sponge larvae consists of a ciliated epithelial sheath, which ensures locomotion, while their internal structure varies from genus to genus. The fate of larval ciliated cells is the most intriguing aspect of metamorphosis. In this review we discuss the fate of larval ciliated cells, the processes going on in cells during metamorphosis at the molecular level and the regulation of this process. The review is based on information about several sponge species with a focus on Halisarca dujardini, Sycon ciliatum and Amphimedon queenslandica. In our model sponge, H. dujardini, ciliated cells leave the larval epithelium during metamorphosis and migrate to the internal cell mass as amoeboid cells to be differentiated into choanocytes of the juvenile sponge. Ciliated cells undergo EMT and internalize within minutes. As EMT involves the disappearance of adherens junctions and as cadherin, the main adherens junction protein, was identified in the transcriptome of several sponges, we suppose that EMT is regulated through cadherin-containing adherens junctions between ciliated cells. We failed to identify the master genes of EMT in the H. dujardini transcriptome, possibly because transcription was absent in the sequenced stages. They may be revealed by a search in the genome. The master genes themselves are controlled by various signaling pathways. Sponges have all the six signaling pathways conserved in Metazoa: Wnt, TGF-beta, Hedgehog, Notch, FGF and NO-dependent pathways. Summarizing the new data about intercellular communication in sponges, we can put forward two main questions regarding metamorphosis: (1) Which of the signaling pathways and in what hierarchical order are involved in metamorphosis? (2) How is the organization of a young sponge related to that of the larva or, in other words, is there a heredity of axes between the larva and the adult sponge?

RevDate: 2019-04-29

Rivera-Yoshida N, Arzola AV, Arias Del Angel JA, et al (2019)

Plastic multicellular development of Myxococcus xanthus: genotype-environment interactions in a physical gradient.

Royal Society open science, 6(3):181730 pii:rsos181730.

In order to investigate the contribution of the physical environment to variation in multicellular development of Myxococcus xanthus, phenotypes developed by different genotypes in a gradient of substrate stiffness conditions were quantitatively characterized. Statistical analysis showed that plastic phenotypes result from the genotype, the substrate conditions and the interaction between them. Also, phenotypes were expressed in two distinguishable scales, the individual and the population levels, and the interaction with the environment showed scale and trait specificity. Overall, our results highlight the constructive role of the physical context in the development of microbial multicellularity, with both ecological and evolutionary implications.

RevDate: 2019-04-29

Hajheidari M, Koncz C, M Bucher (2019)

Chromatin Evolution-Key Innovations Underpinning Morphological Complexity.

Frontiers in plant science, 10:454.

The history of life consists of a series of major evolutionary transitions, including emergence and radiation of complex multicellular eukaryotes from unicellular ancestors. The cells of multicellular organisms, with few exceptions, contain the same genome, however, their organs are composed of a variety of cell types that differ in both structure and function. This variation is largely due to the transcriptional activity of different sets of genes in different cell types. This indicates that complex transcriptional regulation played a key role in the evolution of complexity in eukaryotes. In this review, we summarize how gene duplication and subsequent evolutionary innovations, including the structural evolution of nucleosomes and chromatin-related factors, contributed to the complexity of the transcriptional system and provided a basis for morphological diversity.

RevDate: 2019-04-29
CmpDate: 2019-04-29

Hamada M, Schröder K, Bathia J, et al (2018)

Metabolic co-dependence drives the evolutionarily ancient Hydra-Chlorella symbiosis.

eLife, 7:.

Many multicellular organisms rely on symbiotic associations for support of metabolic activity, protection, or energy. Understanding the mechanisms involved in controlling such interactions remains a major challenge. In an unbiased approach we identified key players that control the symbiosis between Hydra viridissima and its photosynthetic symbiont Chlorella sp. A99. We discovered significant up-regulation of Hydra genes encoding a phosphate transporter and glutamine synthetase suggesting regulated nutrition supply between host and symbionts. Interestingly, supplementing the medium with glutamine temporarily supports in vitro growth of the otherwise obligate symbiotic Chlorella, indicating loss of autonomy and dependence on the host. Genome sequencing of Chlorella sp. A99 revealed a large number of amino acid transporters and a degenerated nitrate assimilation pathway, presumably as consequence of the adaptation to the host environment. Our observations portray ancient symbiotic interactions as a codependent partnership in which exchange of nutrients appears to be the primary driving force.

RevDate: 2019-04-29
CmpDate: 2019-04-29

Soni B, Saha B, S Singh (2018)

Systems cues governing IL6 signaling in leishmaniasis.

Cytokine, 106:169-175.

IL-6 has been proposed to favor the development of Th2 responses and play an important role in the communication between cells of multicellular organisms. They are involved in the regulation of complex cellular processes such as proliferation, differentiation and act as key player during inflammation and immune response. Th2 cytokines play an immunoregulatory role in early infection. Literature says in mice infected with L. major, IL-6 may promote the development of both Th1 and Th2 responses. IL-4 is also considered to be the signature cytokine of Th-2 response. IL-10 was initially characterized as a Th2 cytokine but later on it was proved to be a pleiotropic cytokine, secreted from different cell types including the macrophages. A major challenge is to understand how these complex non-linear processes are connected and regulated. Systems biology approaches may be used to tackle this challenge in an iterative process of quantitative mathematical analysis. In this study, we created an in silico model of IL6 mediated macrophage activation which suffers from an excessive impact of the negative feedback loop involving SOCS3. The strategy adopted in this framework may help to reduce the complexity of the leishmanial IL6 model analysis and also laydown various physiological or pathological conditions of IL6 signaling in future.

RevDate: 2019-04-26

Krishnan A, Degnan BM, SM Degnan (2019)

The first identification of complete Eph-ephrin signalling in ctenophores and sponges reveals a role for neofunctionalization in the emergence of signalling domains.

BMC evolutionary biology, 19(1):96 pii:10.1186/s12862-019-1418-z.

BACKGROUND: Animals have a greater diversity of signalling pathways than their unicellular relatives, consistent with the evolution and expansion of these pathways occurring in parallel with the origin of animal multicellularity. However, the genomes of sponges and ctenophores - non-bilaterian basal animals - typically encode no, or far fewer, recognisable signalling ligands compared to bilaterians and cnidarians. For instance, the largest subclass of receptor tyrosine kinases (RTKs) in bilaterians, the Eph receptors (Ephs), are present in sponges and ctenophores, but their cognate ligands, the ephrins, have not yet been detected.

RESULTS: Here, we use an iterative HMM analysis to identify for the first time membrane-bound ephrins in sponges and ctenophores. We also expand the number of Eph-receptor subtypes identified in these animals and in cnidarians. Both sequence and structural analyses are consistent with the Eph ligand binding domain (LBD) and the ephrin receptor binding domain (RBD) having evolved via the co-option of ancient galactose-binding (discoidin-domain)-like and monodomain cupredoxin domains, respectively. Although we did not detect a complete Eph-ephrin signalling pathway in closely-related unicellular holozoans or in other non-metazoan eukaryotes, truncated proteins with Eph receptor LBDs and ephrin RBDs are present in some choanoflagellates. Together, these results indicate that Eph-ephrin signalling was present in the last common ancestor of extant metazoans, and perhaps even in the last common ancestor of animals and choanoflagellates. Either scenario pushes the origin of Eph-ephrin signalling back much earlier than previously reported.

CONCLUSIONS: We propose that the Eph-LBD and ephrin-RBD, which were ancestrally localised in the cytosol, became linked to the extracellular parts of two cell surface proteins before the divergence of sponges and ctenophores from the rest of the animal kingdom. The ephrin-RBD lost the ancestral capacity to bind copper, and the Eph-LBD became linked to an ancient RTK. The identification of divergent ephrin ligands in sponges and ctenophores suggests that these ligands evolve faster than their cognate receptors. As this may be a general phenomena, we propose that the sequence-structure approach used in this study may be usefully applied to other signalling systems where no, or a small number of, ligands have been identified.

RevDate: 2019-04-26
CmpDate: 2019-04-26

Zumberge JA, Love GD, Cárdenas P, et al (2018)

Demosponge steroid biomarker 26-methylstigmastane provides evidence for Neoproterozoic animals.

Nature ecology & evolution, 2(11):1709-1714.

Sterane biomarkers preserved in ancient sedimentary rocks hold promise for tracking the diversification and ecological expansion of eukaryotes. The earliest proposed animal biomarkers from demosponges (Demospongiae) are recorded in a sequence around 100 Myr long of Neoproterozoic-Cambrian marine sedimentary strata from the Huqf Supergroup, South Oman Salt Basin. This C30 sterane biomarker, informally known as 24-isopropylcholestane (24-ipc), possesses the same carbon skeleton as sterols found in some modern-day demosponges. However, this evidence is controversial because 24-ipc is not exclusive to demosponges since 24-ipc sterols are found in trace amounts in some pelagophyte algae. Here, we report a new fossil sterane biomarker that co-occurs with 24-ipc in a suite of late Neoproterozoic-Cambrian sedimentary rocks and oils, which possesses a rare hydrocarbon skeleton that is uniquely found within extant demosponge taxa. This sterane is informally designated as 26-methylstigmastane (26-mes), reflecting the very unusual methylation at the terminus of the steroid side chain. It is the first animal-specific sterane marker detected in the geological record that can be unambiguously linked to precursor sterols only reported from extant demosponges. These new findings strongly suggest that demosponges, and hence multicellular animals, were prominent in some late Neoproterozoic marine environments at least extending back to the Cryogenian period.

RevDate: 2019-04-23

Gunaratne PH, Pan Y, Rao AK, et al (2019)

Activating p53 family member TAp63: A novel therapeutic strategy for targeting p53-altered tumors.

Cancer [Epub ahead of print].

BACKGROUND: Over 96% of high-grade ovarian carcinomas and 50% of all cancers are characterized by alterations in the p53 gene. Therapeutic strategies to restore and/or reactivate the p53 pathway have been challenging. By contrast, p63, which shares many of the downstream targets and functions of p53, is rarely mutated in cancer.

METHODS: A novel strategy is presented for circumventing alterations in p53 by inducing the tumor-suppressor isoform TAp63 (transactivation domain of tumor protein p63) through its direct downstream target, microRNA-130b (miR-130b), which is epigenetically silenced and/or downregulated in chemoresistant ovarian cancer.

RESULTS: Treatment with miR-130b resulted in: 1) decreased migration/invasion in HEYA8 cells (p53 wild-type) and disruption of multicellular spheroids in OVCAR8 cells (p53-mutant) in vitro, 2) sensitization of HEYA8 and OVCAR8 cells to cisplatin (CDDP) in vitro and in vivo, and 3) transcriptional activation of TAp63 and the B-cell lymphoma (Bcl)-inhibitor B-cell lymphoma 2-like protein 11 (BIM). Overexpression of TAp63 was sufficient to decrease cell viability, suggesting that it is a critical downstream effector of miR-130b. In vivo, combined miR-130b plus CDDP exhibited greater therapeutic efficacy than miR-130b or CDDP alone. Mice that carried OVCAR8 xenograft tumors and were injected with miR-130b in 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) liposomes had a significant decrease in tumor burden at rates similar to those observed in CDDP-treated mice, and 20% of DOPC-miR-130b plus CDDP-treated mice were living tumor free. Systemic injections of scL-miR-130b plus CDDP in a clinically tested, tumor-targeted nanocomplex (scL) improved survival in 60% and complete remissions in 40% of mice that carried HEYA8 xenografts.

CONCLUSIONS: The miR-130b/TAp63 axis is proposed as a new druggable pathway that has the potential to uncover broad-spectrum therapeutic options for the majority of p53-altered cancers.

RevDate: 2019-04-22

Sudianto E (2019)

Digest: Banding together to battle adversaries has its consequences.

Why did life evolve from single-celled to multicellular organisms? Could there be advantages to this transition? What about associated fitness costs? Kapsetaki and West (2019) found that, although multicellularity allows Chlorella sorokiniana to avoid predation from similarly-sized predators, it also reduces their competitiveness when resources are limited. This article is protected by copyright. All rights reserved.

RevDate: 2019-04-22
CmpDate: 2019-04-22

Woo C, An C, Xu S, et al (2018)

Taxonomic diversity of fungi deposited from the atmosphere.

The ISME journal, 12(8):2051-2060.

Fungi release spores into the global atmosphere. The emitted spores are deposited to the surface of the Earth by sedimentation (dry deposition) and precipitation (wet deposition), and therefore contribute to the global cycling of substances. However, knowledge is scarce regarding the diversities of fungi deposited from the atmosphere. Here, an automatic dry and wet deposition sampler and high-throughput sequencing plus quantitative PCR were used to observe taxonomic diversities and flux densities of atmospheric fungal deposition. Taxon-specific fungal deposition velocities and aerodynamic diameters (da) were determined using a collocated cascade impactor for volumetric, particle-size-resolved air sampling. Large multicellular spore-producing dothideomycetes (da ≥ 10.0 μm) were predominant in dry deposition, with a mean velocity of 0.80 cm s-1 for all fungal taxa combined. Higher taxonomic richness was observed in fungal assemblages in wet deposition than in dry deposition, suggesting the presence of fungal taxa that are deposited only in wet form. In wet deposition, agaricomycetes, including mushroom-forming fungi, and sordariomycetes, including plant pathogenic species, were enriched, indicating that such fungal spores serve as nuclei in clouds, and/or are discharged preferentially during precipitation. Moreover, this study confirmed that fungal assemblage memberships and structures were significantly different between dry and wet deposition (P-test, p < 0.001). Overall, these findings suggest taxon-specific involvement of fungi in precipitation, and provide important insights into potential links between environmental changes that can disturb regional microbial communities (e.g., deforestation) and changes in precipitation patterns that might be mediated by changes in microbial communities in the atmosphere.

RevDate: 2019-04-19

Lehtonen J, GA Parker (2019)

Evolution of the Two Sexes under Internal Fertilization and Alternative Evolutionary Pathways.

The American naturalist, 193(5):702-716.

Transition from isogamy to anisogamy, hence males and females, leads to sexual selection, sexual conflict, sexual dimorphism, and sex roles. Gamete dynamics theory links biophysics of gamete limitation, gamete competition, and resource requirements for zygote survival and assumes broadcast spawning. It makes testable predictions, but most comparative tests use volvocine algae, which feature internal fertilization. We broaden this theory by comparing broadcast-spawning predictions with two plausible internal-fertilization scenarios: gamete casting/brooding (one mating type retains gametes internally, the other broadcasts them) and packet casting/brooding (one type retains gametes internally, the other broadcasts packets containing gametes, which are released for fertilization). Models show that predictions are remarkably robust to these radical changes, yielding (1) isogamy under low gamete limitation, low gamete competition, and similar required resources for gametes and zygotes, (2) anisogamy when gamete competition and/or limitation are higher and when zygotes require more resources than gametes, as is likely as multicellularity develops, (3) a positive correlation between multicellular complexity and anisogamy ratio, and (4) under gamete competition, only brooders becoming female. Thus, gamete dynamics theory represents a potent rationale for isogamy/anisogamy and makes similar testable predictions for broadcast spawners and internal fertilizers, regardless of whether anisogamy or internal fertilization evolved first.

RevDate: 2019-04-19

Olito C, T Connallon (2019)

Sexually Antagonistic Variation and the Evolution of Dimorphic Sexual Systems.

The American naturalist, 193(5):688-701.

Multicellular Eukaryotes use a broad spectrum of sexual reproduction strategies, ranging from simultaneous hermaphroditism to complete dioecy (separate sexes). The evolutionary pathway from hermaphroditism to dioecy involves the spread of sterility alleles that eliminate female or male reproductive functions, producing unisexual individuals. Classical theory predicts that evolutionary transitions to dioecy are feasible when female and male sex functions genetically trade off with one another (allocation to sex functions is sexually antagonistic) and rates of self-fertilization and inbreeding depression are high within the ancestral hermaphrodite population. We show that genetic linkage between sterility alleles and loci under sexually antagonistic selection significantly alters these classical predictions. We identify three specific consequences of linkage for the evolution of dimorphic sexual systems. First, linkage broadens conditions for the invasion of unisexual sterility alleles, facilitating transitions to sexual systems that are intermediate between hermaphroditism and dioecy (androdioecy and gynodioecy). Second, linkage elevates the equilibrium frequencies of unisexual individuals within androdioecious and gynodioecious populations, which promotes subsequent transitions to full dioecy. Third, linkage dampens the role of inbreeding during transitions to androdioecy and gynodioecy, making these transitions feasible in outbred populations. We discuss implications of these results for the evolution of dimorphic reproductive systems and sex chromosomes.

RevDate: 2019-04-18
CmpDate: 2019-04-18

Glass DS, IH Riedel-Kruse (2018)

A Synthetic Bacterial Cell-Cell Adhesion Toolbox for Programming Multicellular Morphologies and Patterns.

Cell, 174(3):649-658.e16.

Synthetic multicellular systems hold promise as models for understanding natural development of biofilms and higher organisms and as tools for engineering complex multi-component metabolic pathways and materials. However, such efforts require tools to adhere cells into defined morphologies and patterns, and these tools are currently lacking. Here, we report a 100% genetically encoded synthetic platform for modular cell-cell adhesion in Escherichia coli, which provides control over multicellular self-assembly. Adhesive selectivity is provided by a library of outer membrane-displayed nanobodies and antigens with orthogonal intra-library specificities, while affinity is controlled by intrinsic adhesin affinity, competitive inhibition, and inducible expression. We demonstrate the resulting capabilities for quantitative rational design of well-defined morphologies and patterns through homophilic and heterophilic interactions, lattice-like self-assembly, phase separation, differential adhesion, and sequential layering. Compatible with synthetic biology standards, this adhesion toolbox will enable construction of high-level multicellular designs and shed light on the evolutionary transition to multicellularity.

RevDate: 2019-04-16

Pérez P, Soto T, Gómez-Gil E, et al (2019)

Functional interaction between Cdc42 and the stress MAPK signaling pathway during the regulation of fission yeast polarized growth.

International microbiology : the official journal of the Spanish Society for Microbiology pii:10.1007/s10123-019-00072-6 [Epub ahead of print].

Cell polarization can be defined as the generation and maintenance of directional cellular organization. The spatial distribution and protein or lipid composition of the cell are not symmetric but organized in specialized domains which allow cells to grow and acquire a certain shape that is closely linked to their physiological function. The establishment and maintenance of polarized growth requires the coordination of diverse processes including cytoskeletal dynamics, membrane trafficking, and signaling cascade regulation. Some of the major players involved in the selection and maintenance of sites for polarized growth are Rho GTPases, which recognize the polarization site and transmit the signal to regulatory proteins of the cytoskeleton. Additionally, cytoskeletal organization, polarized secretion, and endocytosis are controlled by signaling pathways including those mediated by mitogen-activated protein kinases (MAPKs). Rho GTPases and the MAPK signaling pathways are strongly conserved from yeast to mammals, suggesting that the basic mechanisms of polarized growth have been maintained throughout evolution. For this reason, the study of how polarized growth is established and regulated in simple organisms such as the fission yeast Schizosaccharomyces pombe has contributed to broaden our knowledge about these processes in multicellular organisms. We review here the function of the Cdc42 GTPase and the stress activated MAPK (SAPK) signaling pathways during fission yeast polarized growth, and discuss the relevance of the crosstalk between both pathways.

RevDate: 2019-04-13

Qian XX, Liu J, Menguy N, et al (2019)

Identification of novel species of marine magnetotactic bacteria affiliated with Nitrospirae phylum.

Environmental microbiology reports [Epub ahead of print].

Magnetotactic bacteria (MTB) are a group of Gram-negative bacteria characterized by synthesizing magnetosomes and swimming along geomagnetic field lines. Phylogenetically, they belong to different taxonomic lineages including Proteobacteria, Nitrospirae, Omnitrophica, Latescibacteria, and Planctomycetes phyla on the phylogenetic tree. To date, six Nitrospirae MTB phylotypes have been identified from freshwater or low salinity environments and described in the literature. Here we report the identification of two Nitrospirae MTB phylotypes collected, for the first time, from the marine environment. Both have a spherical morphology with a cell size of ~ 5 μM and similar motility but are different colors (black-brown and ivory-white) under the optic microscope. They synthesized bullet-shaped iron-oxide magnetosomes that were arranged in multiple bundles of chains. Moreover, the cytoplasm of the black-brown Nitrospirae MTB contained sulfur inclusions that conferred on cells a rough, granular appearance. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that they are two novel species and cluster with the previously reported MTB affiliated with the phylum Nitrospirae, thus extending the distribution of Nitrospirae MTB from freshwater to the marine environment. This article is protected by copyright. All rights reserved.

RevDate: 2019-04-12

Laundon D, Larson BT, McDonald K, et al (2019)

The architecture of cell differentiation in choanoflagellates and sponge choanocytes.

PLoS biology, 17(4):e3000226 pii:PBIOLOGY-D-18-01101 [Epub ahead of print].

Although collar cells are conserved across animals and their closest relatives, the choanoflagellates, little is known about their ancestry, their subcellular architecture, or how they differentiate. The choanoflagellate Salpingoeca rosetta expresses genes necessary for animal development and can alternate between unicellular and multicellular states, making it a powerful model for investigating the origin of animal multicellularity and mechanisms underlying cell differentiation. To compare the subcellular architecture of solitary collar cells in S. rosetta with that of multicellular 'rosette' colonies and collar cells in sponges, we reconstructed entire cells in 3D through transmission electron microscopy on serial ultrathin sections. Structural analysis of our 3D reconstructions revealed important differences between single and colonial choanoflagellate cells, with colonial cells exhibiting a more amoeboid morphology consistent with higher levels of macropinocytotic activity. Comparison of multiple reconstructed rosette colonies highlighted the variable nature of cell sizes, cell-cell contact networks, and colony arrangement. Importantly, we uncovered the presence of elongated cells in some rosette colonies that likely represent a distinct and differentiated cell type, pointing toward spatial cell differentiation. Intercellular bridges within choanoflagellate colonies displayed a variety of morphologies and connected some but not all neighbouring cells. Reconstruction of sponge choanocytes revealed ultrastructural commonalities but also differences in major organelle composition in comparison to choanoflagellates. Together, our comparative reconstructions uncover the architecture of cell differentiation in choanoflagellates and sponge choanocytes and constitute an important step in reconstructing the cell biology of the last common ancestor of animals.

RevDate: 2019-04-09

Rêgo A, Messina FJ, Z Gompert (2019)

Dynamics of genomic change during evolutionary rescue in the seed beetle Callosobruchus maculatus.

Molecular ecology [Epub ahead of print].

Rapid adaptation can prevent extinction when populations are exposed to extremely marginal or stressful environments. Factors that affect the likelihood of evolutionary rescue from extinction have been identified, but much less is known about the evolutionary dynamics (e.g., rates and patterns of allele frequency change) and genomic basis of successful rescue, particularly in multicellular organisms. We conducted an evolve-and-resequence experiment to investigate the dynamics of evolutionary rescue at the genetic level in the cowpea seed beetle, Callosobruchus maculatus, when it is experimentally shifted to a stressful host plant, lentil. Low survival (~1%) at the onset of the experiment caused population decline. But adaptive evolution quickly rescued the population, with survival rates climbing to 69% by the F5 generation and 90% by the F10 generation. Population genomic data showed that rescue likely was caused by rapid evolutionary change at multiple loci, with many alleles fixing or nearly fixing within five generations of selection on lentil. Selection on these loci was only moderately consistent in time, but parallel evolutionary changes were evident in sublines formed after the lentil line had passed through a bottleneck. By comparing estimates of selection and genomic change on lentil across five independent C. maculatus lines (the new lentil-adapted line, three long-established lines, and one case of failed evolutionary rescue), we found that adaptation on lentil occurred via somewhat idiosyncratic evolutionary changes. Overall, our results suggest that evolutionary rescue in this system can be caused by very strong selection on multiple loci driving rapid and pronounced genomic change. This article is protected by copyright. All rights reserved.

RevDate: 2019-04-08

Nguyen H, Koehl MAR, Oakes C, et al (2019)

Effects of cell morphology and attachment to a surface on the hydrodynamic performance of unicellular choanoflagellates.

Journal of the Royal Society, Interface, 16(150):20180736.

Choanoflagellates, eukaryotes that are important predators on bacteria in aquatic ecosystems, are closely related to animals and are used as a model system to study the evolution of animals from protozoan ancestors. The choanoflagellate Salpingoeca rosetta has a complex life cycle with different morphotypes, some unicellular and some multicellular. Here we use computational fluid dynamics to study the hydrodynamics of swimming and feeding by different unicellular stages of S. rosetta: a swimming cell with a collar of prey-capturing microvilli surrounding a single flagellum, a thecate cell attached to a surface and a dispersal-stage cell with a slender body, long flagellum and short collar. We show that a longer flagellum increases swimming speed, longer microvilli reduce speed and cell shape only affects speed when the collar is very short. The flux of prey-carrying water into the collar capture zone is greater for swimming than sessile cells, but this advantage decreases with collar size. Stalk length has little effect on flux for sessile cells. We show that ignoring the collar, as earlier models have done, overestimates flux and greatly overestimates the benefit to feeding performance of swimming versus being attached, and of a longer stalk for attached cells.

RevDate: 2019-04-06

Baade T, Paone C, Baldrich A, et al (2019)

Clustering of integrin β cytoplasmic domains triggers nascent adhesion formation and reveals a protozoan origin of the integrin-talin interaction.

Scientific reports, 9(1):5728 pii:10.1038/s41598-019-42002-6.

Integrins and integrin-dependent cell-matrix adhesions are essential for a number of physiological processes. Integrin function is tightly regulated via binding of cytoplasmic proteins to integrin intracellular domains. Yet, the complexity of cell-matrix adhesions in mammals, with more than 150 core adhesome proteins, complicates the analysis of integrin-associated protein complexes. Interestingly, the evolutionary origin of integrins dates back before the transition from unicellular life to complex multicellular animals. Though unicellular relatives of metazoa have a less complex adhesome, nothing is known about the initial steps of integrin activation and adhesion complex assembly in protozoa. Therefore, we developed a minimal, microscope-based system using chimeric integrins to investigate receptor-proximal events during focal adhesion assembly. Clustering of the human integrin β1 tail led to recruitment of talin, kindlin, and paxillin and mutation of the known talin binding site abolished recruitment of this protein. Proteins indirectly linked to integrins, such as vinculin, migfilin, p130CAS, or zyxin were not enriched around the integrin β1 tail. With the exception of integrin β4 and integrin β8, the cytoplasmic domains of all human integrin β subunits supported talin binding. Likewise, the cytoplasmic domains of integrin β subunits expressed by the protozoan Capsaspora owczarzaki readily recruited talin and this interaction was based on an evolutionary conserved NPXY/F amino acid motif. The results we present here validate the use of our novel microscopic assay to uncover details of integrin-based protein-protein interactions in a cellular context and suggest that talin binding to integrin β cytoplasmic tails is an ancient feature of integrin regulation.

RevDate: 2019-04-07

Bohlin J, JH Pettersson (2019)

Evolution of Genomic Base Composition: From Single Cell Microbes to Multicellular Animals.

Computational and structural biotechnology journal, 17:362-370 pii:S2001-0370(18)30183-1.

Whole genome sequencing (WGS) of thousands of microbial genomes has provided considerable insight into evolutionary mechanisms in the microbial world. While substantially fewer eukaryotic genomes are available for analyses the number is rapidly increasing. This mini-review summarizes broadly evolutionary dynamics of base composition in the different domains of life from the perspective of prokaryotes. Common and different evolutionary mechanisms influencing genomic base composition in eukaryotes and prokaryotes are discussed. The conclusion from the data currently available suggests that while there are similarities there are also striking differences in how genomic base composition has evolved within prokaryotes and eukaryotes. For instance, homologous recombination appears to increase GC content locally in eukaryotes due to a non-selective process termed GC-biased gene conversion (gBGC). For prokaryotes on the other hand, increase in genomic GC content seems to be driven by the environment and selection. We find that similar phenomena observed for some organisms in each respective domain may be caused by very different mechanisms: while gBGC and recombination rates appear to explain the negative correlation between GC3 (GC content based on the third codon nucleotides) and genome size in some eukaryotes uptake of AT rich DNA sequences is the main reason for a similar negative correlation observed in prokaryotes. We provide further examples that indicate that base composition in prokaryotes and eukaryotes have evolved under very different constraints.

RevDate: 2019-04-03

Gulli JG, Herron MD, WC Ratcliff (2019)

Evolution of altruistic cooperation among nascent multicellular organisms.

Evolution; international journal of organic evolution [Epub ahead of print].

Cooperation is a classic solution to hostile environments that limit individual survival. In extreme cases this may lead to the evolution of new types of biological individuals (e.g., eusocial super-organisms). We examined the potential for inter-individual cooperation to evolve via experimental evolution, challenging nascent multicellular 'snowflake yeast' with an environment in which solitary multicellular clusters experienced low survival. In response, snowflake yeast evolved to form cooperative groups composed of thousands of multicellular clusters that typically survive selection. Group formation occurred through the creation of protein aggregates, only arising in strains with high (>2%) rates of cell death. Nonetheless, it was adaptive and repeatable, though ultimately evolutionarily unstable. Extracellular protein aggregates act as a common good, as they can be exploited by cheats that do not contribute to aggregate production. These results highlight the importance of group formation as a mechanism for surviving environmental stress, and underscore the remarkable ease with which even simple multicellular entities may evolve-and lose-novel social traits. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-29

Pedchenko V, Bauer R, Pokidysheva EN, et al (2019)

A chloride ring is an ancient evolutionary innovation mediating the assembly of the collagen IV scaffold of basement membranes.

The Journal of biological chemistry pii:RA119.007426 [Epub ahead of print].

Collagen IV scaffold is a principal component of the basement membrane (BM), a specialized extracellular matrix that is essential for animal multicellularity and tissue evolution. Scaffold assembly begins with the trimerization of α-chains into protomers inside the cell, which then are secreted and undergo oligomerization outside the cell. For the ubiquitous scaffold composed of α1 and α2 chains, both intracellular and extracellular stages are mediated by the non-collagenous domain (NC1). The association of protomers is chloride-dependent, whereby chloride ions induce interactions of protomers' trimeric NC1 domains leading to NC1 hexamer formation. Here, we investigated the mechanisms, kinetics, and functionality of the chloride ion-mediated protomer assembly by using a single-chain technology to produce a stable NC1 trimer comprising α1, α2, and α1 NC1 monomers. We observed that in the presence of chloride, the single-chain NC1 trimer self-assembles into a hexamer, for which the crystal structure was determined. We discovered that a chloride ring, comprising twelve ions, induces the assembly of and stabilizes the NC1 hexamer. Furthermore, we found that the chloride ring is evolutionarily conserved across all animals, first appearing in cnidarians. These findings reveal a fundamental role for the chloride ring in the assembly of collagen IV scaffolds of BMs, a critical event enabling tissue evolution and development. Moreover, the single-chain technology is foundational for generating trimeric NC1 domains of other α-chain compositions to investigate the α121, α345, and α565 collagen IV scaffolds and to develop therapies for managing Alport syndrome, Goodpasture's disease, and cancerous tumor growth.

RevDate: 2019-03-28

Zhu SQ, Zhang YJ, Abbas MN, et al (2019)

Hedgehog promotes cell proliferation in the midgut of silkworm, Bombyx mori.

Insect science [Epub ahead of print].

The Hedgehog (Hh) signaling pathway is one of the major regulators of embryonic development and tissue homeostasis in multicellular organisms. However, the role of this pathway in the silkworm, especially in the silkworm midgut, remains poorly understood. Here, we report that Bombyx mori Hedgehog (BmHh) is expressed in most tissues of silkworm larvae and that its functions are well-conserved throughout evolution. We further demonstrate that the mRNA of four Hh signaling components, BmHh ligand, BmPtch receptor, signal transducer BmSmo and transcription factor BmCi, are all upregulated following Escherichia coli (E. coli) or Bacillus thuringiensis (Bt) infection, indicating the activation of the Hh pathway. Simultaneously, midgut cell proliferation is strongly promoted. Conversely, the repression of Hh signal transduction with double stranded RNA or cyclopamine inhibits the expression of BmHh and BmCi and reduces cell proliferation. Overall, these findings provide new insights into the Hh signaling pathway in the silkworm, Bombyx mori. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-28

Arimoto A, Nishitsuji K, Higa Y, et al (2019)

A siphonous macroalgal genome suggests convergent functions of homeobox genes in algae and land plants.

DNA research : an international journal for rapid publication of reports on genes and genomes pii:5419551 [Epub ahead of print].

Genome evolution and development of unicellular, multinucleate macroalgae (siphonous algae) are poorly known, although various multicellular organisms have been studied extensively. To understand macroalgal developmental evolution, we assembled the ∼26 Mb genome of a siphonous green alga, Caulerpa lentillifera, with high contiguity, containing 9,311 protein-coding genes. Molecular phylogeny using 107 nuclear genes indicates that the diversification of the class Ulvophyceae, including C. lentillifera, occurred before the split of the Chlorophyceae and Trebouxiophyceae. Compared with other green algae, the TALE superclass of homeobox genes, which expanded in land plants, shows a series of lineage-specific duplications in this siphonous macroalga. Plant hormone signalling components were also expanded in a lineage-specific manner. Expanded transport regulators, which show spatially different expression, suggest that the structural patterning strategy of a multinucleate cell depends on diversification of nuclear pore proteins. These results not only imply functional convergence of duplicated genes among green plants, but also provide insight into evolutionary roots of green plants. Based on the present results, we propose cellular and molecular mechanisms involved in the structural differentiation in the siphonous alga.

RevDate: 2019-04-01

Stucky BJ, Balhoff JP, Barve N, et al (2019)

Developing a vocabulary and ontology for modeling insect natural history data: example data, use cases, and competency questions.

Biodiversity data journal, 7:e33303 pii:33303.

Insects are possibly the most taxonomically and ecologically diverse class of multicellular organisms on Earth. Consequently, they provide nearly unlimited opportunities to develop and test ecological and evolutionary hypotheses. Currently, however, large-scale studies of insect ecology, behavior, and trait evolution are impeded by the difficulty in obtaining and analyzing data derived from natural history observations of insects. These data are typically highly heterogeneous and widely scattered among many sources, which makes developing robust information systems to aggregate and disseminate them a significant challenge. As a step towards this goal, we report initial results of a new effort to develop a standardized vocabulary and ontology for insect natural history data. In particular, we describe a new database of representative insect natural history data derived from multiple sources (but focused on data from specimens in biological collections), an analysis of the abstract conceptual areas required for a comprehensive ontology of insect natural history data, and a database of use cases and competency questions to guide the development of data systems for insect natural history data. We also discuss data modeling and technology-related challenges that must be overcome to implement robust integration of insect natural history data.

RevDate: 2019-03-27

Kolasa M, Ścibior R, Mazur MA, et al (2019)

How Hosts Taxonomy, Trophy, and Endosymbionts Shape Microbiome Diversity in Beetles.

Microbial ecology pii:10.1007/s00248-019-01358-y [Epub ahead of print].

Bacterial communities play a crucial role in the biology, ecology, and evolution of multicellular organisms. In this research, the microbiome of 24 selected beetle species representing five families (Carabidae, Staphylinidae, Curculionidae, Chrysomelidae, Scarabaeidae) and three trophic guilds (carnivorous, herbivorous, detrivorous) was examined using 16S rDNA sequencing on the Illumina platform. The aim of the study was to compare diversity within and among species on various levels of organization, including evaluation of the impact of endosymbiotic bacteria. Collected data showed that beetles possess various bacterial communities and that microbiota of individuals of particular species hosts are intermixed. The most diverse microbiota were found in Carabidae and Scarabaeidae; the least diverse, in Staphylinidae. On higher organization levels, the diversity of bacteria was more dissimilar between families, while the most distinct with respect to their microbiomes were trophic guilds. Moreover, eight taxa of endosymbiotic bacteria were detected including common genera such as Wolbachia, Rickettsia, and Spiroplasma, as well as the rarely detected Cardinium, Arsenophonus, Buchnera, Sulcia, Regiella, and Serratia. There were no correlations among the abundance of the most common Wolbachia and Rickettsia; a finding that does not support the hypothesis that these bacteria occur interchangeably. The abundance of endosymbionts only weakly and negatively correlates with diversity of the whole microbiome in beetles. Overall, microbiome diversity was found to be more dependent on host phylogeny than on the abundance of endosymbionts. This is the first study in which bacteria diversity is compared between numerous species of beetles in a standardized manner.

RevDate: 2019-03-29

Bielska E, Birch PRJ, Buck AH, et al (2019)

Highlights of the mini-symposium on extracellular vesicles in inter-organismal communication, held in Munich, Germany, August 2018.

Journal of extracellular vesicles, 8(1):1590116 pii:1590116.

All living organisms secrete molecules for intercellular communication. Recent research has revealed that extracellular vesicles (EVs) play an important role in inter-organismal cell-to-cell communication by transporting diverse messenger molecules, including RNA, DNA, lipids and proteins. These discoveries have raised fundamental questions regarding EV biology. How are EVs biosynthesized and loaded with messenger/cargo molecules? How are EVs secreted into the extracellular matrix? What are the EV uptake mechanisms of recipient cells? As EVs are produced by all kind of organisms, from unicellular bacteria and protists, filamentous fungi and oomycetes, to complex multicellular life forms such as plants and animals, basic research in diverse model systems is urgently needed to shed light on the multifaceted biology of EVs and their role in inter-organismal communications. To help catalyse progress in this emerging field, a mini-symposium was held in Munich, Germany in August 2018. This report highlights recent progress and major questions being pursued across a very diverse group of model systems, all united by the question of how EVs contribute to inter-organismal communication.

RevDate: 2019-03-26

Moffitt L, Karimnia N, Stephens A, et al (2019)

Therapeutic Targeting of Collective Invasion in Ovarian Cancer.

International journal of molecular sciences, 20(6): pii:ijms20061466.

Ovarian cancer is the seventh most commonly diagnosed cancer amongst women and has the highest mortality rate of all gynaecological malignancies. It is a heterogeneous disease attributed to one of three cell types found within the reproductive milieu: epithelial, stromal, and germ cell. Each histotype differs in etiology, pathogenesis, molecular biology, risk factors, and prognosis. Furthermore, the origin of ovarian cancer remains unclear, with ovarian involvement secondary to the contribution of other gynaecological tissues. Despite these complexities, the disease is often treated as a single entity, resulting in minimal improvement to survival rates since the introduction of platinum-based chemotherapy over 30 years ago. Despite concerted research efforts, ovarian cancer remains one of the most difficult cancers to detect and treat, which is in part due to the unique mode of its dissemination. Ovarian cancers tend to invade locally to neighbouring tissues by direct extension from the primary tumour, and passively to pelvic and distal organs within the peritoneal fluid or ascites as multicellular spheroids. Once at their target tissue, ovarian cancers, like most epithelial cancers including colorectal, melanoma, and breast, tend to invade as a cohesive unit in a process termed collective invasion, driven by specialized cells termed "leader cells". Emerging evidence implicates leader cells as essential drivers of collective invasion and metastasis, identifying collective invasion and leader cells as a viable target for the management of metastatic disease. However, the development of targeted therapies specifically against this process and this subset of cells is lacking. Here, we review our understanding of metastasis, collective invasion, and the role of leader cells in ovarian cancer. We will discuss emerging research into the development of novel therapies targeting collective invasion and the leader cell population.

RevDate: 2019-03-23

Krizsán K, Almási É, Merényi Z, et al (2019)

Transcriptomic atlas of mushroom development reveals conserved genes behind complex multicellularity in fungi.

Proceedings of the National Academy of Sciences of the United States of America pii:1817822116 [Epub ahead of print].

The evolution of complex multicellularity has been one of the major transitions in the history of life. In contrast to simple multicellular aggregates of cells, it has evolved only in a handful of lineages, including animals, embryophytes, red and brown algae, and fungi. Despite being a key step toward the evolution of complex organisms, the evolutionary origins and the genetic underpinnings of complex multicellularity are incompletely known. The development of fungal fruiting bodies from a hyphal thallus represents a transition from simple to complex multicellularity that is inducible under laboratory conditions. We constructed a reference atlas of mushroom formation based on developmental transcriptome data of six species and comparisons of >200 whole genomes, to elucidate the core genetic program of complex multicellularity and fruiting body development in mushroom-forming fungi (Agaricomycetes). Nearly 300 conserved gene families and >70 functional groups contained developmentally regulated genes from five to six species, covering functions related to fungal cell wall remodeling, targeted protein degradation, signal transduction, adhesion, and small secreted proteins (including effector-like orphan genes). Several of these families, including F-box proteins, expansin-like proteins, protein kinases, and transcription factors, showed expansions in Agaricomycetes, many of which convergently expanded in multicellular plants and/or animals too, reflecting convergent solutions to genetic hurdles imposed by complex multicellularity among independently evolved lineages. This study provides an entry point to studying mushroom development and complex multicellularity in one of the largest clades of complex eukaryotic organisms.

RevDate: 2019-03-22

Wielgoss S, Wolfensberger R, Sun L, et al (2019)

Social genes are selection hotspots in kin groups of a soil microbe.

Science (New York, N.Y.), 363(6433):1342-1345.

The composition of cooperative systems, including animal societies, organismal bodies, and microbial groups, reflects their past and shapes their future evolution. However, genomic diversity within many multiunit systems remains uncharacterized, limiting our ability to understand and compare their evolutionary character. We have analyzed genomic and social-phenotype variation among 120 natural isolates of the cooperative bacterium Myxococcus xanthus derived from six multicellular fruiting bodies. Each fruiting body was composed of multiple lineages radiating from a unique recent ancestor. Genomic evolution was concentrated in selection hotspots associated with evolutionary change in social phenotypes. Synonymous mutations indicated that kin lineages within the same fruiting body often first diverged from a common ancestor more than 100 generations ago. Thus, selection appears to promote endemic diversification of kin lineages that remain together over long histories of local interaction, thereby potentiating social coevolution.

RevDate: 2019-03-20

Talbert PB, Meers MP, S Henikoff (2019)

Old cogs, new tricks: the evolution of gene expression in a chromatin context.

Nature reviews. Genetics pii:10.1038/s41576-019-0105-7 [Epub ahead of print].

Sophisticated gene-regulatory mechanisms probably evolved in prokaryotes billions of years before the emergence of modern eukaryotes, which inherited the same basic enzymatic machineries. However, the epigenomic landscapes of eukaryotes are dominated by nucleosomes, which have acquired roles in genome packaging, mitotic condensation and silencing parasitic genomic elements. Although the molecular mechanisms by which nucleosomes are displaced and modified have been described, just how transcription factors, histone variants and modifications and chromatin regulators act on nucleosomes to regulate transcription is the subject of considerable ongoing study. We explore the extent to which these transcriptional regulatory components function in the context of the evolutionarily ancient role of chromatin as a barrier to processes acting on DNA and how chromatin proteins have diversified to carry out evolutionarily recent functions that accompanied the emergence of differentiation and development in multicellular eukaryotes.

RevDate: 2019-04-03
CmpDate: 2019-04-03

Xu S, Stapley J, Gablenz S, et al (2019)

Low genetic variation is associated with low mutation rate in the giant duckweed.

Nature communications, 10(1):1243 pii:10.1038/s41467-019-09235-5.

Mutation rate and effective population size (Ne) jointly determine intraspecific genetic diversity, but the role of mutation rate is often ignored. Here we investigate genetic diversity, spontaneous mutation rate and Ne in the giant duckweed (Spirodela polyrhiza). Despite its large census population size, whole-genome sequencing of 68 globally sampled individuals reveals extremely low intraspecific genetic diversity. Assessed under natural conditions, the genome-wide spontaneous mutation rate is at least seven times lower than estimates made for other multicellular eukaryotes, whereas Ne is large. These results demonstrate that low genetic diversity can be associated with large-Ne species, where selection can reduce mutation rates to very low levels. This study also highlights that accurate estimates of mutation rate can help to explain seemingly unexpected patterns of genome-wide variation.

RevDate: 2019-03-20

Kapsetaki SE, SA West (2019)

The costs and benefits of multicellular group formation in algae.

Evolution; international journal of organic evolution [Epub ahead of print].

The first step in the evolution of complex multicellular organisms involves single cells forming a cooperative group. Consequently, to understand multicellularity, we need to understand the costs and benefits associated with multicellular group formation. We found that in the facultatively multicellular algae Chlorella sorokiniana: (1) the presence of the flagellate Ochromonas danica or the crustacean Daphnia magna leads to the formation of multicellular groups; (2) the formation of multicellular groups reduces predation by O. danica, but not by the larger predator D. magna; (3) under conditions of relatively low light intensity, where competition for light is greater, multicellular groups grow slower than single cells; (4) in the absence of live predators, the proportion of cells in multicellular groups decreases at a rate that does not vary with light intensity. These results can explain why, in cases such as this algae species, multicellular group formation is facultative, in response to the presence of predators.

RevDate: 2019-03-16

Goh GH, Maloney SK, Mark PJ, et al (2019)

Episodic Ultradian Events-Ultradian Rhythms.

Biology, 8(1): pii:biology8010015.

In the fast lane of chronobiology, ultradian events are short-term rhythms that have been observed since the beginning of modern biology and were quantified about a century ago. They are ubiquitous in all biological systems and found in all organisms, from unicellular organisms to mammals, and from single cells to complex biological functions in multicellular animals. Since these events are aperiodic and last for a few minutes to a few hours, they are better classified as episodic ultradian events (EUEs). Their origin is unclear. However, they could have a molecular basis and could be controlled by hormonal inputs-in vertebrates, they originate from the activity of the central nervous system. EUEs are receiving increasing attention but their aperiodic nature requires specific sampling and analytic tools. While longer scale rhythms are adaptations to predictable changes in the environment, in theory, EUEs could contribute to adaptation by preparing organisms and biological functions for unpredictability.

RevDate: 2019-03-13

Shoemark DK, Ziegler B, Watanabe H, et al (2019)

Emergence of a Thrombospondin Superfamily at the Origin of Metazoans.

Molecular biology and evolution pii:5377293 [Epub ahead of print].

Extracellular matrix (ECM) is considered central to the evolution of metazoan multicellularity, however the repertoire of ECM proteins in non-bilaterians remains unclear. Thrombospondins (TSPs) are known to be well-conserved from cnidarians to vertebrates, yet to date have been considered a unique family, principally studied for matricellular functions in vertebrates. Through searches utilizing the highly-conserved C-terminal region of TSPs we identify undisclosed new families of thrombospondin-related proteins in metazoans, designated mega-thrombospondin, sushi-thrombospondin and poriferan-thrombospondin, each with a distinctive phylogenetic distribution. These proteins share the TSP C-terminal region domain architecture, as determined by domain composition and analysis of molecular models against known structures. Mega-thrombospondins, the only form identified in ctenophores, are typically >2700aa and are also characterized by N-terminal leucine-rich repeats and central cadherin/immunoglobulin domains. In cnidarians, which have a well-defined ECM, Mega-TSP was expressed throughout embryogenesis in Nematostella vectensis, with dynamic endodermal expression in larvae and primary polyps and widespread ectodermal expression in adult N. vectensis and Hydra magnipapillata polyps. Hydra Mega-TSP was also expressed during regeneration and siRNA-silencing of Mega-TSP in Hydra caused specific blockade of head regeneration. Molecular phylogenetic analyses based on the conserved TSP C-terminal region identified each of the TSP-related groups to form clades distinct from the canonical TSPs. We discuss models for the evolution of the newly-defined TSP superfamily by gene duplications, radiation and gene losses from a debut in the last metazoan common ancestor. Together, the data provide new insight into the evolution of ECM and tissue organization in metazoans.

RevDate: 2019-03-13

Lenhart BA, Meeks B, HA Murphy (2019)

Variation in Filamentous Growth and Response to Quorum-Sensing Compounds in Environmental Isolates of Saccharomyces cerevisiae.

G3 (Bethesda, Md.) pii:g3.119.400080 [Epub ahead of print].

In fungi, filamentous growth is a major developmental transition that occurs in response to environmental cues. In diploid Saccharomyces cerevisiae, it is known as pseudohyphal growth and presumed to be a foraging mechanism. Rather than unicellular growth, multicellular filaments composed of elongated, attached cells spread over and into surfaces. This morphogenetic switch can be induced through quorum sensing with the aromatic alcohols phenylethanol and tryptophol. Most research investigating pseudohyphal growth has been conducted in a single lab background, ∑1278b. To investigate the natural variation in this phenotype and its induction, we assayed the diverse 100-genomes collection of environmental isolates. Using computational image analysis, we quantified the production of pseudohyphae and observed a large amount of variation. Population origin was significantly associated with pseudohyphal growth, with the West African population having the most. Surprisingly, most strains showed little or no response to exogenous phenylethanol or tryptophol. We also investigated the amount of natural genetic variation in pseudohyphal growth using a mapping population derived from a highly-heterozygous clinical isolate that contained as much phenotypic variation as the environmental panel. A bulk-segregant analysis uncovered five major peaks with candidate loci that have been implicated in the ∑1278b background. Our results indicate that the filamentous growth response is a generalized, highly variable phenotype in natural populations, while response to quorum sensing molecules is surprisingly rare. These findings highlight the importance of coupling studies in tractable lab strains with natural isolates in order to understand the relevance and distribution of well-studied traits.

RevDate: 2019-03-29

Sicard A, Pirolles E, Gallet R, et al (2019)

A multicellular way of life for a multipartite virus.

eLife, 8: pii:43599.

A founding paradigm in virology is that the spatial unit of the viral replication cycle is an individual cell. Multipartite viruses have a segmented genome where each segment is encapsidated separately. In this situation the viral genome is not recapitulated in a single virus particle but in the viral population. How multipartite viruses manage to efficiently infect individual cells with all segments, thus with the whole genome information, is a long-standing but perhaps deceptive mystery. By localizing and quantifying the genome segments of a nanovirus in host plant tissues we show that they rarely co-occur within individual cells. We further demonstrate that distinct segments accumulate independently in different cells and that the viral system is functional through complementation across cells. Our observation deviates from the classical conceptual framework in virology and opens an alternative possibility (at least for nanoviruses) where the infection can operate at a level above the individual cell level, defining a viral multicellular way of life.

RevDate: 2019-03-21

Ruiz MC, Kljun J, Turel I, et al (2019)

Comparative antitumor studies of organoruthenium complexes with 8-hydroxyquinolines on 2D and 3D cell models of bone, lung and breast cancer.

Metallomics : integrated biometal science, 11(3):666-675.

The purpose of this work was to screen the antitumor actions of two metal organoruthenium-8-hydroxyquinolinato (Ru-hq) complexes to find a potential novel agent for bone, lung and breast chemotherapies. We showed that ruthenium compounds (1 and 2) impaired the cell viability of human bone (MG-63), lung (A549) and breast (MCF7) cancer cells with greater selectivity and specificity than cisplatin. Besides, complexes 1 and 2 decreased proliferation, migration and invasion on cell monolayers at lower concentrations (2.5-10 μM). In addition, both compounds induced genotoxicity revealed by the micronucleus test, which led to G2/M cell cycle arrest and induced the tumor cells to undergo apoptosis. On the other hand, in multicellular 3D models (multicellular spheroids; MCS), 1 and 2 overcame CDDP presenting lower IC50 values only in MCS of lung origin. Moreover, 1 outperformed 2 in MCS of bone and breast origin. Finally, our findings revealed that both compounds inhibited the cell invasion of multicellular spheroids, showing that complex 1 exhibited the most important antimetastatic action. Taken together, these results indicate that compound 1 is an interesting candidate to be tested on in vivo models as a novel strategy for anticancer therapy.

RevDate: 2019-03-30

Fillinger RJ, MZ Anderson (2019)

Seasons of change: Mechanisms of genome evolution in human fungal pathogens.

Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, 70:165-174.

Fungi are a diverse kingdom of organisms capable of thriving in various niches across the world including those in close association with multicellular eukaryotes. Fungal pathogens that contribute to human disease reside both within the host as commensal organisms of the microbiota and the environment. Their niche of origin dictates how infection initiates but also places specific selective pressures on the fungal pathogen that contributes to its genome organization and genetic repertoire. Recent efforts to catalogue genomic variation among major human fungal pathogens have unveiled evolutionary themes that shape the fungal genome. Mechanisms ranging from large scale changes such as aneuploidy and ploidy cycling as well as more targeted mutations like base substitutions and gene copy number variations contribute to the evolution of these species, which are often under multiple competing selective pressures with their host, environment, and other microbes. Here, we provide an overview of the major selective pressures and mechanisms acting to evolve the genome of clinically important fungal pathogens of humans.

RevDate: 2019-03-06

Kabir M, Wenlock S, Doig AJ, et al (2019)

The Essentiality Status of Mouse Duplicate Gene Pairs Correlates with Developmental Co-Expression Patterns.

Scientific reports, 9(1):3224 pii:10.1038/s41598-019-39894-9.

During the evolution of multicellular eukaryotes, gene duplication occurs frequently to generate new genes and/or functions. A duplicated gene may have a similar function to its ancestral gene. Therefore, it may be expected that duplicated genes are less likely to be critical for the survival of an organism, since there are multiple copies of the gene rendering each individual copy redundant. In this study, we explored the developmental expression patterns of duplicate gene pairs and the relationship between development co-expression and phenotypes resulting from the knockout of duplicate genes in the mouse. We define genes that generate lethal phenotypes in single gene knockout experiments as essential genes. We found that duplicate gene pairs comprised of two essential genes tend to be expressed at different stages of development, compared to duplicate gene pairs with at least one non-essential member, showing that the timing of developmental expression affects the ability of one paralogue to compensate for the loss of the other. Gene essentiality, developmental expression and gene duplication are thus closely linked.

RevDate: 2019-04-04
CmpDate: 2019-04-04

Lurgi M, Thomas T, Wemheuer B, et al (2019)

Modularity and predicted functions of the global sponge-microbiome network.

Nature communications, 10(1):992 pii:10.1038/s41467-019-08925-4.

Defining the organisation of species interaction networks and unveiling the processes behind their assembly is fundamental to understanding patterns of biodiversity, community stability and ecosystem functioning. Marine sponges host complex communities of microorganisms that contribute to their health and survival, yet the mechanisms behind microbiome assembly are largely unknown. We present the global marine sponge-microbiome network and reveal a modular organisation in both community structure and function. Modules are linked by a few sponge species that share microbes with other species around the world. Further, we provide evidence that abiotic factors influence the structuring of the sponge microbiome when considering all microbes present, but biotic interactions drive the assembly of more intimately associated 'core' microorganisms. These findings suggest that both ecological and evolutionary processes are at play in host-microbe network assembly. We expect mechanisms behind microbiome assembly to be consistent across multicellular hosts throughout the tree of life.

RevDate: 2019-03-07

El Albani A, Mangano MG, Buatois LA, et al (2019)

Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago.

Proceedings of the National Academy of Sciences of the United States of America, 116(9):3431-3436.

Evidence for macroscopic life in the Paleoproterozoic Era comes from 1.8 billion-year-old (Ga) compression fossils [Han TM, Runnegar B (1992) Science 257:232-235; Knoll et al. (2006) Philos Trans R Soc Lond B 361:1023-1038], Stirling biota [Bengtson S et al. (2007) Paleobiology 33:351-381], and large colonial organisms exhibiting signs of coordinated growth from the 2.1-Ga Francevillian series, Gabon. Here we report on pyritized string-shaped structures from the Francevillian Basin. Combined microscopic, microtomographic, geochemical, and sedimentologic analyses provide evidence for biogenicity, and syngenicity and suggest that the structures underwent fossilization during early diagenesis close to the sediment-water interface. The string-shaped structures are up to 6 mm across and extend up to 170 mm through the strata. Morphological and 3D tomographic reconstructions suggest that the producer may have been a multicellular or syncytial organism able to migrate laterally and vertically to reach food resources. A possible modern analog is the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds at times of starvation. This unique ecologic window established in an oxygenated, shallow-marine environment represents an exceptional record of the biosphere following the crucial changes that occurred in the atmosphere and ocean in the aftermath of the great oxidation event (GOE).

RevDate: 2019-03-08

Trigos AS, Pearson RB, Papenfuss AT, et al (2019)

Somatic mutations in early metazoan genes disrupt regulatory links between unicellular and multicellular genes in cancer.

eLife, 8: pii:40947.

Extensive transcriptional alterations are observed in cancer, many of which activate core biological processes established in unicellular organisms or suppress differentiation pathways formed in metazoans. Through rigorous, integrative analysis of genomics data from a range of solid tumors, we show many transcriptional changes in tumors are tied to mutations disrupting regulatory interactions between unicellular and multicellular genes within human gene regulatory networks (GRNs). Recurrent point mutations were enriched in regulator genes linking unicellular and multicellular subnetworks, while copy-number alterations affected downstream target genes in distinctly unicellular and multicellular regions of the GRN. Our results depict drivers of tumourigenesis as genes that created key regulatory links during the evolution of early multicellular life, whose dysfunction creates widespread dysregulation of primitive elements of the GRN. Several genes we identified as important in this process were associated with drug response, demonstrating the potential clinical value of our approach.

RevDate: 2019-02-25

Xie P, Gao M, Wang C, et al (2019)

SuperCT: a supervised-learning framework for enhanced characterization of single-cell transcriptomic profiles.

Nucleic acids research pii:5364134 [Epub ahead of print].

Characterization of individual cell types is fundamental to the study of multicellular samples. Single-cell RNAseq techniques, which allow high-throughput expression profiling of individual cells, have significantly advanced our ability of this task. Currently, most of the scRNA-seq data analyses are commenced with unsupervised clustering. Clusters are often assigned to different cell types based on the enriched canonical markers. However, this process is inefficient and arbitrary. In this study, we present a technical framework of training the expandable supervised-classifier in order to reveal the single-cell identities as soon as the single-cell expression profile is input. Using multiple scRNA-seq datasets we demonstrate the superior accuracy, robustness, compatibility and expandability of this new solution compared to the traditional methods. We use two examples of the model upgrade to demonstrate how the projected evolution of the cell-type classifier is realized.

RevDate: 2019-02-27

Zhang L, Tan Y, Fan S, et al (2019)

Phylostratigraphic analysis of gene co-expression network reveals the evolution of functional modules for ovarian cancer.

Scientific reports, 9(1):2623 pii:10.1038/s41598-019-40023-9.

Ovarian cancer (OV) is an extremely lethal disease. However, the evolutionary machineries of OV are still largely unknown. Here, we used a method that combines phylostratigraphy information with gene co-expression networks to extensively study the evolutionary compositions of OV. The present co-expression network construction yielded 18,549 nodes and 114,985 edges based on 307 OV expression samples obtained from the Genome Data Analysis Centers database. A total of 20 modules were identified as OV related clusters. The human genome sequences were divided into 19 phylostrata (PS), the majority (67.45%) of OV genes was already present in the eukaryotic ancestor. There were two strong peaks of the emergence of OV genes screened by hypergeometric test: the evolution of the multicellular metazoan organisms (PS5 and PS6, P value = 0.002) and the emergence of bony fish (PS11 and PS12, P value = 0.009). Hence, the origin of OV is far earlier than its emergence. The integrated analysis of the topology of OV modules and the phylogenetic data revealed an evolutionary pattern of OV in human, namely, OV modules have arisen step by step during the evolution of the respective lineages. New genes have evolved and become locked into a pathway, where more and more biological pathways are fixed into OV modules by recruiting new genes during human evolution.

RevDate: 2019-02-24

Herron MD, Borin JM, Boswell JC, et al (2019)

De novo origins of multicellularity in response to predation.

Scientific reports, 9(1):2328 pii:10.1038/s41598-019-39558-8.

The transition from unicellular to multicellular life was one of a few major events in the history of life that created new opportunities for more complex biological systems to evolve. Predation is hypothesized as one selective pressure that may have driven the evolution of multicellularity. Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations. Considerable variation exists in the evolved multicellular life cycles, with both cell number and propagule size varying among isolates. Survival assays show that evolved multicellular traits provide effective protection against predation. These results support the hypothesis that selection imposed by predators may have played a role in some origins of multicellularity.

RevDate: 2019-03-29

Dunning LT, Olofsson JK, Parisod C, et al (2019)

Lateral transfers of large DNA fragments spread functional genes among grasses.

Proceedings of the National Academy of Sciences of the United States of America pii:1810031116 [Epub ahead of print].

A fundamental tenet of multicellular eukaryotic evolution is that vertical inheritance is paramount, with natural selection acting on genetic variants transferred from parents to offspring. This lineal process means that an organism's adaptive potential can be restricted by its evolutionary history, the amount of standing genetic variation, and its mutation rate. Lateral gene transfer (LGT) theoretically provides a mechanism to bypass many of these limitations, but the evolutionary importance and frequency of this process in multicellular eukaryotes, such as plants, remains debated. We address this issue by assembling a chromosome-level genome for the grass Alloteropsis semialata, a species surmised to exhibit two LGTs, and screen it for other grass-to-grass LGTs using genomic data from 146 other grass species. Through stringent phylogenomic analyses, we discovered 57 additional LGTs in the A. semialata nuclear genome, involving at least nine different donor species. The LGTs are clustered in 23 laterally acquired genomic fragments that are up to 170 kb long and have accumulated during the diversification of Alloteropsis. The majority of the 59 LGTs in A. semialata are expressed, and we show that they have added functions to the recipient genome. Functional LGTs were further detected in the genomes of five other grass species, demonstrating that this process is likely widespread in this globally important group of plants. LGT therefore appears to represent a potent evolutionary force capable of spreading functional genes among distantly related grass species.

RevDate: 2019-03-21
CmpDate: 2019-03-21

Lipinska AP, Serrano-Serrano ML, Cormier A, et al (2019)

Rapid turnover of life-cycle-related genes in the brown algae.

Genome biology, 20(1):35 pii:10.1186/s13059-019-1630-6.

BACKGROUND: Sexual life cycles in eukaryotes involve a cyclic alternation between haploid and diploid phases. While most animals possess a diploid life cycle, many plants and algae alternate between multicellular haploid (gametophyte) and diploid (sporophyte) generations. In many algae, gametophytes and sporophytes are independent and free-living and may present dramatic phenotypic differences. The same shared genome can therefore be subject to different, even conflicting, selection pressures during each of the life cycle generations. Here, we analyze the nature and extent of genome-wide, generation-biased gene expression in four species of brown algae with contrasting levels of dimorphism between life cycle generations.

RESULTS: We show that the proportion of the transcriptome that is generation-specific is broadly associated with the level of phenotypic dimorphism between the life cycle stages. Importantly, our data reveals a remarkably high turnover rate for life-cycle-related gene sets across the brown algae and highlights the importance not only of co-option of regulatory programs from one generation to the other but also of a role for newly emerged, lineage-specific gene expression patterns in the evolution of the gametophyte and sporophyte developmental programs in this major eukaryotic group. Moreover, we show that generation-biased genes display distinct evolutionary modes, with gametophyte-biased genes evolving rapidly at the coding sequence level whereas sporophyte-biased genes tend to exhibit changes in their patterns of expression.

CONCLUSION: Our analysis uncovers the characteristics, expression patterns, and evolution of generation-biased genes and underlines the selective forces that shape this previously underappreciated source of phenotypic diversity.

RevDate: 2019-03-12
CmpDate: 2019-03-11

Raza Q, Choi JY, Li Y, et al (2019)

Evolutionary rate covariation analysis of E-cadherin identifies Raskol as a regulator of cell adhesion and actin dynamics in Drosophila.

PLoS genetics, 15(2):e1007720 pii:PGENETICS-D-18-01886.

The adherens junction couples the actin cytoskeletons of neighboring cells to provide the foundation for multicellular organization. The core of the adherens junction is the cadherin-catenin complex that arose early in the evolution of multicellularity to link actin to intercellular adhesions. Over time, evolutionary pressures have shaped the signaling and mechanical functions of the adherens junction to meet specific developmental and physiological demands. Evolutionary rate covariation (ERC) identifies proteins with correlated fluctuations in evolutionary rate that can reflect shared selective pressures and functions. Here we use ERC to identify proteins with evolutionary histories similar to the Drosophila E-cadherin (DE-cad) ortholog. Core adherens junction components α-catenin and p120-catenin displayed positive ERC correlations with DE-cad, indicating that they evolved under similar selective pressures during evolution between Drosophila species. Further analysis of the DE-cad ERC profile revealed a collection of proteins not previously associated with DE-cad function or cadherin-mediated adhesion. We then analyzed the function of a subset of ERC-identified candidates by RNAi during border cell (BC) migration and identified novel genes that function to regulate DE-cad. Among these, we found that the gene CG42684, which encodes a putative GTPase activating protein (GAP), regulates BC migration and adhesion. We named CG42684 raskol ("to split" in Russian) and show that it regulates DE-cad levels and actin protrusions in BCs. We propose that Raskol functions with DE-cad to restrict Ras/Rho signaling and help guide BC migration. Our results demonstrate that a coordinated selective pressure has shaped the adherens junction and this can be leveraged to identify novel components of the complexes and signaling pathways that regulate cadherin-mediated adhesion.

RevDate: 2019-03-25
CmpDate: 2019-03-25

Chen IK, Satinsky BM, Velicer GJ, et al (2019)

sRNA-pathway genes regulating myxobacterial development exhibit clade-specific evolution.

Evolution & development, 21(2):82-95.

Small non-coding RNAs (sRNAs) control bacterial gene expression involved in a wide range of important cellular processes. In the highly social bacterium Myxococcus xanthus, the sRNA Pxr prevents multicellular fruiting-body development when nutrients are abundant. Pxr was discovered from the evolution of a developmentally defective strain (OC) into a developmentally proficient strain (PX). In OC, Pxr is constitutively expressed and blocks development even during starvation. In PX, one mutation deactivates Pxr allowing development to proceed. We screened for transposon mutants that suppress the OC defect and thus potentially reveal new Pxr-pathway components. Insertions significantly restoring development were found in four genes-rnd, rnhA, stkA and Mxan_5793-not previously associated with an sRNA activity. Phylogenetic analysis suggests that the Pxr pathway was constructed within the Cystobacterineae suborder both by co-option of genes predating the Myxococcales order and incorporation of a novel gene (Mxan_5793). Further, the sequence similarity of rnd, rnhA and stkA homologs relative to M. xanthus alleles was found to decrease greatly among species beyond the Cystobacterineae suborder compared to the housekeeping genes examined. Finally, ecological context differentially affected the developmental phenotypes of distinct mutants, with implications for the evolution of development in variable environments.

RevDate: 2019-02-19

Dipp-Álvarez M, A Cruz-Ramírez (2019)

A Phylogenetic Study of the ANT Family Points to a preANT Gene as the Ancestor of Basal and euANT Transcription Factors in Land Plants.

Frontiers in plant science, 10:17.

Comparative genomics has revealed that members of early divergent lineages of land plants share a set of highly conserved transcription factors (TFs) with flowering plants. While gene copy numbers have expanded through time, it has been predicted that diversification, co-option, and reassembly of gene regulatory networks implicated in development are directly related to morphological innovations that led to more complex land plant bodies. Examples of key networks have been deeply studied in Arabidopsis thaliana, such as those involving the AINTEGUMENTA (ANT) gene family that encodes AP2-type TFs. These TFs play significant roles in plant development such as the maintenance of stem cell niches, the correct development of the embryo and the formation of lateral organs, as well as fatty acid metabolism. Previously, it has been hypothesized that the common ancestor of mosses and vascular plants encoded two ANT genes that later diversified in seed plants. However, algae and bryophyte sequences have been underrepresented from such phylogenetic analyses. To understand the evolution of ANT in a complete manner, we performed phylogenetic analyses of ANT protein sequences of representative species from across the Streptophyta clade, including algae, liverworts, and hornworts, previously unrepresented. Moreover, protein domain architecture, selection analyses, and regulatory cis elements prediction, allowed us to propose a scenario of how the evolution of ANT genes occurred. In this study we show that a duplication of a preANT-like gene in the ancestor of embryophytes may have given rise to the land plant-exclusive basalANT and euANT lineages. We hypothesize that the absence of euANT-type and basalANT-type sequences in algae, and its presence in extant land plant species, suggests that the divergence of pre-ANT into basal and eu-ANT clades in embryophytes may have influenced the conquest of land by plants, as ANT TFs play important roles in tolerance to desiccation and the establishment, maintenance, and development of complex multicellular structures which either became more complex or appeared in land plants.

RevDate: 2019-02-22

Junqueira Alves C, Yotoko K, Zou H, et al (2019)

Origin and evolution of plexins, semaphorins, and Met receptor tyrosine kinases.

Scientific reports, 9(1):1970 pii:10.1038/s41598-019-38512-y.

The transition from unicellular to multicellular organisms poses the question as to when genes that regulate cell-cell interactions emerged during evolution. The receptor and ligand pairing of plexins and semaphorins regulates cellular interactions in a wide range of developmental and physiological contexts. We surveyed here genomes of unicellular eukaryotes and of non-bilaterian and bilaterian Metazoa and performed phylogenetic analyses to gain insight into the evolution of plexin and semaphorin families. Remarkably, we detected plexins and semaphorins in unicellular choanoflagellates, indicating their evolutionary origin in a common ancestor of Choanoflagellida and Metazoa. The plexin domain structure is conserved throughout all clades; in contrast, semaphorins are structurally diverse. Choanoflagellate semaphorins are transmembrane proteins with multiple fibronectin type III domains following the N-terminal Sema domain (termed Sema-FN). Other previously not yet described semaphorin classes include semaphorins of Ctenophora with tandem immunoglobulin domains (Sema-IG) and secreted semaphorins of Echinoderamata (Sema-SP, Sema-SI). Our study also identified Met receptor tyrosine kinases (RTKs), which carry a truncated plexin extracellular domain, in several bilaterian clades, indicating evolutionary origin in a common ancestor of Bilateria. In addition, a novel type of Met-like RTK with a complete plexin extracellular domain was detected in Lophotrochozoa and Echinodermata (termed Met-LP RTK). Our findings are consistent with an ancient function of plexins and semaphorins in regulating cytoskeletal dynamics and cell adhesion that predates their role as axon guidance molecules.

RevDate: 2019-04-09
CmpDate: 2019-04-09

Ferrari C, Proost S, Janowski M, et al (2019)

Kingdom-wide comparison reveals the evolution of diurnal gene expression in Archaeplastida.

Nature communications, 10(1):737 pii:10.1038/s41467-019-08703-2.

Plants have adapted to the diurnal light-dark cycle by establishing elaborate transcriptional programs that coordinate many metabolic, physiological, and developmental responses to the external environment. These transcriptional programs have been studied in only a few species, and their function and conservation across algae and plants is currently unknown. We performed a comparative transcriptome analysis of the diurnal cycle of nine members of Archaeplastida, and we observed that, despite large phylogenetic distances and dramatic differences in morphology and lifestyle, diurnal transcriptional programs of these organisms are similar. Expression of genes related to cell division and the majority of biological pathways depends on the time of day in unicellular algae but we did not observe such patterns at the tissue level in multicellular land plants. Hence, our study provides evidence for the universality of diurnal gene expression and elucidates its evolutionary history among different photosynthetic eukaryotes.

RevDate: 2019-02-13

Oborník M (2019)

In the beginning was the word: How terminology drives our understanding of endosymbiotic organelles.

Microbial cell (Graz, Austria), 6(2):134-141 pii:MIC0178E150.

The names we give objects of research, to some extent, predispose our ways of thinking about them. Misclassifications of Oomycota, Microsporidia, Myxosporidia, and Helicosporidia have obviously affected not only their formal taxonomic names, but also the methods and approaches with which they have been investigated. Therefore, it is important to name biological entities with accurate terms in order to avoid discrepancies in researching them. The endosymbiotic origin of mitochondria and plastids is now the most accepted scenario for their evolution. Since it is apparent that there is no natural definitive border between bacteria and semiautonomous organelles, I propose that mitochondria and plastids should be called bacteria and classified accordingly, in the bacterial classification system. I discuss some consequences of this approach, including: i) the resulting "changes" in the abundances of bacteria, ii) the definitions of terms like microbiome or multicellularity, and iii) the concept of endosymbiotic domestication.

RevDate: 2019-03-20

Tan J, He Q, Pentz JT, et al (2019)

Copper oxide nanoparticles promote the evolution of multicellularity in yeast.

Nanotoxicology [Epub ahead of print].

Engineered nanomaterials are rapidly becoming an essential component of modern technology. Thousands of tons of nanomaterials are manufactured, used, and subsequently released into the environment annually. While the presence of these engineered nanomaterials in the environment has profound effects on various biological systems in the short term, little work has been done to understand their consequences over long, evolutionary timescales. The evolution of multicellularity is a critical step in the origin of complex life on Earth and a unique strategy for microorganisms to alleviate adverse environmental impacts, yet the selective pressures that favor the evolution of multicellular groups remain poorly understood. Here, we show that engineered nanomaterials, specifically copper oxide nanoparticles (CuO NPs), promote the evolution of undifferentiated multicellularity in Baker's yeast (Saccharomyces cerevisiae strain Y55). Transcriptomic analysis suggests that multicellularity mitigates the negative effects of CuO NPs in yeast cells and shifts their metabolism from alcoholic fermentation towards aerobic respiration, potentially increasing resource efficiency and providing a fitness benefit during CuO NP exposure. Competition assays also confirm that the multicellular yeast possesses a fitness advantage when exposed to CuO NPs. Our results, therefore, demonstrate that nanoparticles can have profound and unexpected evolutionary consequences, underscoring the need for a more comprehensive understanding of the long-term biological impacts of nanomaterial pollution.

RevDate: 2019-04-04

Peyraud R, Mbengue M, Barbacci A, et al (2019)

Intercellular cooperation in a fungal plant pathogen facilitates host colonization.

Proceedings of the National Academy of Sciences of the United States of America, 116(8):3193-3201.

Cooperation is associated with major transitions in evolution such as the emergence of multicellularity. It is central to the evolution of many complex traits in nature, including growth and virulence in pathogenic bacteria. Whether cells of multicellular parasites function cooperatively during infection remains, however, largely unknown. Here, we show that hyphal cells of the fungal pathogen Sclerotinia sclerotiorum reprogram toward division of labor to facilitate the colonization of host plants. Using global transcriptome sequencing, we reveal that gene expression patterns diverge markedly in cells at the center and apex of hyphae during Arabidopsis thaliana colonization compared with in vitro growth. We reconstructed a genome-scale metabolic model for S. sclerotiorum and used flux balance analysis to demonstrate metabolic heterogeneity supporting division of labor between hyphal cells. Accordingly, continuity between the central and apical compartments of invasive hyphae was required for optimal growth in planta Using a multicell model of fungal hyphae, we show that this cooperative functioning enhances fungal growth predominantly during host colonization. Our work identifies cooperation in fungal hyphae as a mechanism emerging at the multicellular level to support host colonization and virulence.

RevDate: 2019-02-05

Fischer MS, Jonkers W, NL Glass (2019)

Integration of Self and Non-self Recognition Modulates Asexual Cell-to-Cell Communication in Neurospora crassa.

Genetics pii:genetics.118.301780 [Epub ahead of print].

Cells rarely exist alone, which drives the evolution of diverse mechanisms for identifying and responding appropriately to the presence of other nearby cells. Filamentous fungi depend on somatic cell-to-cell communication and fusion for the development and maintenance of a multicellular, interconnected colony that is characteristic of this group of organisms. The filamentous fungus Neurospora crassa is a model for investigating the mechanisms of somatic cell-to-cell communication and fusion. N. crassa cells chemotropically grow toward genetically similar cells, which ultimately make physical contact and undergo cell fusion. Here, we describe the development of a Pprm1-luciferase reporter system that differentiates whether genes function upstream or downstream of a conserved MAP-Kinase (MAPK) signaling complex by using a set of mutants required for communication and cell fusion. The vast majority of these mutants are deficient for self-fusion and for fusion when paired with wild type cells. However, the Δham-11 mutant is unique in that fails to undergo self-fusion, but chemotropic interactions and cell fusion are restored in Δham-11 + wild-type interactions. In genetically dissimilar cells, chemotropic interactions are regulated by genetic differences at doc-1 and doc-2, which regulate pre-fusion non-self recognition; cells with dissimilar doc-1 and doc-2 alleles show greatly reduced cell fusion frequencies. Here, we show that HAM-11 functions in parallel with the DOC-1 and DOC-2 proteins to regulate activity of the MAPK signaling complex. Together our data support a model of integrated self and non-self recognition processes that modulate somatic cell-to-cell communication in N. crassa.

RevDate: 2019-02-05

Gonçalves DS, Ferreira MDS, AJ Guimarães (2019)

Extracellular Vesicles from the Protozoa Acanthamoeba castellanii: Their Role in Pathogenesis, Environmental Adaptation and Potential Applications.

Bioengineering (Basel, Switzerland), 6(1): pii:bioengineering6010013.

Extracellular vesicles (EVs) are membranous compartments of distinct cellular origin and biogenesis, displaying different sizes and include exosomes, microvesicles, and apoptotic bodies. The EVs have been described in almost every living organism, from simple unicellular to higher evolutionary scale multicellular organisms, such as mammals. Several functions have been attributed to these structures, including roles in energy acquisition, cell-to-cell communication, gene expression modulation and pathogenesis. In this review, we described several aspects of the recently characterized EVs of the protozoa Acanthamoeba castellanii, a free-living amoeba (FLA) of emerging epidemiological importance, and compare their features to other parasites' EVs. These A. castellanii EVs are comprised of small microvesicles and exosomes and carry a wide range of molecules involved in many biological processes like cell signaling, carbohydrate metabolism and proteolytic activity, such as kinases, glucanases, and proteases, respectively. Several biomedical applications of these EVs have been proposed lately, including their use in vaccination, biofuel production, and the pharmaceutical industry, such as platforms for drug delivery.

RevDate: 2019-02-26

Baluška F, A Reber (2019)

Sentience and Consciousness in Single Cells: How the First Minds Emerged in Unicellular Species.

BioEssays : news and reviews in molecular, cellular and developmental biology, 41(3):e1800229.

A reductionistic, bottom-up, cellular-based concept of the origins of sentience and consciousness has been put forward. Because all life is based on cells, any evolutionary theory of the emergence of sentience and consciousness must be grounded in mechanisms that take place in prokaryotes, the simplest unicellular species. It has been posited that subjective awareness is a fundamental property of cellular life. It emerges as an inherent feature of, and contemporaneously with, the very first life-forms. All other varieties of mentation are the result of evolutionary mechanisms based on this singular event. Therefore, all forms of sentience and consciousness evolve from this original instantiation in prokaryotes. It has also been identified that three cellular structures and mechanisms that likely play critical roles here are excitable membranes, oscillating cytoskeletal polymers, and structurally flexible proteins. Finally, basic biophysical principles are proposed to guide those processes that underly the emergence of supracellular sentience from cellular sentience in multicellular organisms.

RevDate: 2019-02-04

Kosach V, Shkarina K, Kravchenko A, et al (2018)

Nucleocytoplasmic distribution of S6K1 depends on the density and motility of MCF-7 cells in vitro.

F1000Research, 7:1332.

Background: The ribosomal protein S6 kinase 1 (S6K1) is one of the main components of the mTOR/S6K signal transduction pathway, which controls cellular metabolism, autophagy, growth, and proliferation. Overexpression of S6K1 was detected in tumors of different origin including breast cancer, and correlated with the worse disease outcome. In addition, significant accumulation of S6K1 was found in the nuclei of breast carcinoma cells suggesting the implication of kinase nuclear substrates in tumor progression. However, this aspect of S6K1 functioning is still poorly understood. The main aim of the present work was to study the subcellular localization of S6K1 in breast cancer cells with the focus on cell migration. Methods: Multicellular spheroids of MCF-7 cells were generated using agarose-coated Petri dishes. Cell migration was induced by spheroids seeding onto adhesive growth surface and subsequent cultivation for 24 to 72 hours. The subcellular localization of S6K1 was studied in human normal breast and cancer tissue samples, 2D and 3D MCF-7 cell cultures using immunofluorescence analysis and confocal microscopy. Results: Analysis of histological sections of human breast tissue samples revealed predominantly nuclear localization of S6K1 in breast malignant cells and its mainly cytoplasmic localization in conditionally normal cells. In vitro studies of MCF-7 cells demonstrated that the subcellular localization of S6K1 depends on the cell density in the monolayer culture. S6K1 relocalization from the cytoplasm into the nucleus was detected in MCF-7 cells migrating from multicellular spheroids onto growth surface. Immunofluorescence analysis of S6K1 and immunocoprecipitation assay revealed the colocalization and interaction between S6K1 and transcription factor TBR2 (T-box brain protein 2) in MCF-7 cells. Conclusions: Subcellular localization of S6K1 depends on the density and locomotor activity of the MCF-7 cells.

RevDate: 2019-02-24

Helsen J, Frickel J, Jelier R, et al (2019)

Network hubs affect evolvability.

PLoS biology, 17(1):e3000111 pii:PBIOLOGY-D-18-01275.

The regulatory processes in cells are typically organized into complex genetic networks. However, it is still unclear how this network structure modulates the evolution of cellular regulation. One would expect that mutations in central and highly connected modules of a network (so-called hubs) would often result in a breakdown and therefore be an evolutionary dead end. However, a new study by Koubkova-Yu and colleagues finds that in some circumstances, altering a hub can offer a quick evolutionary advantage. Specifically, changes in a hub can induce significant phenotypic changes that allow organisms to move away from a local fitness peak, whereas the fitness defects caused by the perturbed hub can be mitigated by mutations in its interaction partners. Together, the results demonstrate how network architecture shapes and facilitates evolutionary adaptation.

RevDate: 2019-03-29

Muley VY, Akhter Y, S Galande (2019)

PDZ Domains Across the Microbial World: Molecular Link to the Proteases, Stress Response, and Protein Synthesis.

Genome biology and evolution, 11(3):644-659.

The PSD-95/Dlg-A/ZO-1 (PDZ) domain is highly expanded, diversified, and well distributed across metazoa where it assembles diverse signaling components by virtue of interactions with other proteins in a sequence-specific manner. In contrast, in the microbial world they are reported to be involved in protein quality control during stress response. The distribution, functions, and origins of PDZ domain-containing proteins in the prokaryotic organisms remain largely unexplored. We analyzed 7,852 PDZ domain-containing proteins in 1,474 microbial genomes in this context. PDZ domain-containing proteins from planctomycetes, myxobacteria, and other eubacteria occupying terrestrial and aquatic niches are found to be in multiple copies within their genomes. Over 93% of the 7,852 PDZ domain-containing proteins were classified into 12 families including six novel families based on additional structural and functional domains present in these proteins. The higher PDZ domain encoding capacity of the investigated organisms was observed to be associated with adaptation to the ecological niche where multicellular life might have originated and flourished. Predicted subcellular localization of PDZ domain-containing proteins and their genomic context argue in favor of crucial roles in translation and membrane remodeling during stress response. Based on rigorous sequence, structure, and phylogenetic analyses, we propose that the highly diverse PDZ domain of the uncharacterized Fe-S oxidoreductase superfamily, exclusively found in gladobacteria and several anaerobes and acetogens, might represent the most ancient form among all the existing PDZ domains.

RevDate: 2019-03-29

Parey E, A Crombach (2019)

Evolution of the Drosophila melanogaster Chromatin Landscape and Its Associated Proteins.

Genome biology and evolution, 11(3):660-677.

In the nucleus of eukaryotic cells, genomic DNA associates with numerous protein complexes and RNAs, forming the chromatin landscape. Through a genome-wide study of chromatin-associated proteins in Drosophila cells, five major chromatin types were identified as a refinement of the traditional binary division into hetero- and euchromatin. These five types were given color names in reference to the Greek word chroma. They are defined by distinct but overlapping combinations of proteins and differ in biological and biochemical properties, including transcriptional activity, replication timing, and histone modifications. In this work, we assess the evolutionary relationships of chromatin-associated proteins and present an integrated view of the evolution and conservation of the fruit fly Drosophila melanogaster chromatin landscape. We combine homology prediction across a wide range of species with gene age inference methods to determine the origin of each chromatin-associated protein. This provides insight into the evolution of the different chromatin types. Our results indicate that for the euchromatic types, YELLOW and RED, young associated proteins are more specialized than old ones; and for genes found in either chromatin type, intron/exon structure is lineage-specific. Next, we provide evidence that a subset of GREEN-associated proteins is involved in a centromere drive in D. melanogaster. Our results on BLUE chromatin support the hypothesis that the emergence of Polycomb Group proteins is linked to eukaryotic multicellularity. In light of these results, we discuss how the regulatory complexification of chromatin links to the origins of eukaryotic multicellularity.

RevDate: 2019-02-26

Nedelcu AM (2019)

Independent evolution of complex development in animals and plants: deep homology and lateral gene transfer.

Development genes and evolution, 229(1):25-34.

The evolution of multicellularity is a premier example of phenotypic convergence: simple multicellularity evolved independently many times, and complex multicellular phenotypes are found in several distant groups. Furthermore, both animal and plant lineages have independently reached extreme levels of morphological, functional, and developmental complexity. This study explores the genetic basis for the parallel evolution of complex multicellularity and development in the animal and green plant (i.e., green algae and land plants) lineages. Specifically, the study (i) identifies the SAND domain-a DNA-binding domain with important roles in the regulation of cell proliferation and differentiation, as unique to animals, green algae, and land plants; and (ii) suggests that the parallel deployment of this ancestral domain in similar regulatory roles could have contributed to the independent evolution of complex development in these distant groups. Given the deep animal-green plant divergence, the limited distribution of the SAND domain is best explained by invoking a lateral gene transfer (LGT) event from a green alga to an early metazoan. The presence of a sequence motif specifically shared by a family of SAND-containing transcription factors involved in the evolution of complex multicellularity in volvocine algae and two types of SAND proteins that emerged early in the evolution of animals is consistent with this scenario. Overall, these findings imply that (i) in addition to be involved in the evolution of similar phenotypes, deep homologous sequences can also contribute to shaping parallel evolutionary trajectories in distant lineages, and (ii) LGT could provide an additional source of latent homologous sequences that can be deployed in analogous roles and affect the evolutionary potentials of distantly related groups.

RevDate: 2019-03-29

Passow CN, Bronikowski AM, Blackmon H, et al (2019)

Contrasting Patterns of Rapid Molecular Evolution within the p53 Network across Mammal and Sauropsid Lineages.

Genome biology and evolution, 11(3):629-643.

Cancer is a threat to multicellular organisms, yet the molecular evolution of pathways that prevent the accumulation of genetic damage has been largely unexplored. The p53 network regulates how cells respond to DNA-damaging stressors. We know little about p53 network molecular evolution as a whole. In this study, we performed comparative genetic analyses of the p53 network to quantify the number of genes within the network that are rapidly evolving and constrained, and the association between lifespan and the patterns of evolution. Based on our previous published data set, we used genomes and transcriptomes of 34 sauropsids and 32 mammals to analyze the molecular evolution of 45 genes within the p53 network. We found that genes in the network exhibited evidence of positive selection and divergent molecular evolution in mammals and sauropsids. Specifically, we found more evidence of positive selection in sauropsids than mammals, indicating that sauropsids have different targets of selection. In sauropsids, more genes upstream in the network exhibited positive selection, and this observation is driven by positive selection in squamates, which is consistent with previous work showing rapid divergence and adaptation of metabolic and stress pathways in this group. Finally, we identified a negative correlation between maximum lifespan and the number of genes with evidence of divergent molecular evolution, indicating that species with longer lifespans likely experienced less variation in selection across the network. In summary, our study offers evidence that comparative genomic approaches can provide insights into how molecular networks have evolved across diverse species.

RevDate: 2019-02-21

Coelho SM, Mignerot L, JM Cock (2019)

Origin and evolution of sex-determination systems in the brown algae.

The New phytologist [Epub ahead of print].

Sexual reproduction is a nearly universal feature of eukaryotic organisms. Meiosis appears to have had a single ancient origin, but the mechanisms underlying male or female sex determination are diverse and have emerged repeatedly and independently in the different eukaryotic groups. The brown algae are a group of multicellular photosynthetic eukaryotes that have a distinct evolutionary history compared with animals and plants, as they have been evolving independently for over 1 billion yr. Here, we review recent work using the brown alga Ectocarpus as a model organism to study haploid sex chromosomes, and highlight how the diversity of reproductive and life cycle features of the brown algae offer unique opportunities to characterize the evolutionary forces and the mechanisms underlying the evolution of sex determination.

RevDate: 2019-01-29

Peel S, Corrigan AM, Ehrhardt B, et al (2019)

Introducing an automated high content confocal imaging approach for Organs-on-Chips.

Lab on a chip, 19(3):410-421.

Organ-Chips are micro-engineered systems that aim to recapitulate the organ microenvironment. Implementation of Organ-Chips within the pharmaceutical industry aims to improve the probability of success of drugs reaching late stage clinical trial by generating models for drug discovery that are of human origin and have disease relevance. We are adopting the use of Organ-Chips for enhancing pre-clinical efficacy and toxicity evaluation and prediction. Whilst capturing cellular phenotype via imaging in response to drug exposure is a useful readout in these models, application has been limited due to difficulties in imaging the chips at scale. Here we created an end-to-end, automated workflow to capture and analyse confocal images of multicellular Organ-Chips to assess detailed cellular phenotype across large batches of chips. By automating this process, we not only reduced acquisition time, but we also minimised process variability and user bias. This enabled us to establish, for the first time, a framework of statistical best practice for Organ-Chip imaging, creating the capability of using Organ-Chips and imaging for routine testing in drug discovery applications that rely on quantitative image data for decision making. We tested our approach using benzbromarone, whose mechanism of toxicity has been linked to mitochondrial damage with subsequent induction of apoptosis and necrosis, and staurosporine, a tool inducer of apoptosis. We also applied this workflow to assess the hepatotoxic effect of an active AstraZeneca drug candidate illustrating its applicability in drug safety assessment beyond testing tool compounds. Finally, we have demonstrated that this approach could be adapted to Organ-Chips of different shapes and sizes through application to a Kidney-Chip.

RevDate: 2019-01-23

Bogdan MJ, T Savin (2018)

Fingering instabilities in tissue invasion: an active fluid model.

Royal Society open science, 5(12):181579 pii:rsos181579.

Metastatic tumours often invade healthy neighbouring tissues by forming multicellular finger-like protrusions emerging from the cancer mass. To understand the mechanical context behind this phenomenon, we here develop a minimalist fluid model of a self-propelled, growing biological tissue. The theory involves only four mechanical parameters and remains analytically trackable in various settings. As an application of the model, we study the evolution of a two-dimensional circular droplet made of our active and expanding fluid, and embedded in a passive non-growing tissue. This system could be used to model the evolution of a carcinoma in an epithelial layer. We find that our description can explain the propensity of tumour tissues to fingering instabilities, as conditioned by the magnitude of active traction and the growth kinetics. We are also able to derive predictions for the tumour size at the onset of metastasis, and for the number of subsequent invasive fingers. Our active fluid model may help describe a wider range of biological processes, including wound healing and developmental patterning.

RevDate: 2019-04-05

Rodríguez-Pascual F (2019)

How evolution made the matrix punch at the multicellularity party.

The Journal of biological chemistry, 294(3):770-771.

The basement membrane is a specialized sheet-like form of the extracellular matrix that provides structural support to epithelial cells and tissues, while influencing multiple biological functions, and was essential in the transition to multicellularity. By exploring a variety of genomes, Darris et al. provide evidence that the emergence and divergence of a multifunctional Goodpasture antigen-binding protein (GPBP), a basement membrane constituent, played a role in this transition. These findings help to explain how GPBP contributed to the formation of these extracellular matrices and to more precisely define the transition to multicellular organisms.

RevDate: 2019-04-05
CmpDate: 2019-04-05

Yoshida T, Prudent M, A D'alessandro (2019)

Red blood cell storage lesion: causes and potential clinical consequences.

Blood transfusion = Trasfusione del sangue, 17(1):27-52.

Red blood cells (RBCs) are a specialised organ that enabled the evolution of multicellular organisms by supplying a sufficient quantity of oxygen to cells that cannot obtain oxygen directly from ambient air via diffusion, thereby fueling oxidative phosphorylation for highly efficient energy production. RBCs have evolved to optimally serve this purpose by packing high concentrations of haemoglobin in their cytosol and shedding nuclei and other organelles. During their circulatory lifetimes in humans of approximately 120 days, RBCs are poised to transport oxygen by metabolic/redox enzymes until they accumulate damage and are promptly removed by the reticuloendothelial system. These elaborate evolutionary adaptions, however, are no longer effective when RBCs are removed from the circulation and stored hypothermically in blood banks, where they develop storage-induced damages ("storage lesions") that accumulate over the shelf life of stored RBCs. This review attempts to provide a comprehensive view of the literature on the subject of RBC storage lesions and their purported clinical consequences by incorporating the recent exponential growth in available data obtained from "omics" technologies in addition to that published in more traditional literature. To summarise this vast amount of information, the subject is organised in figures with four panels: i) root causes; ii) RBC storage lesions; iii) physiological effects; and iv) reported outcomes. The driving forces for the development of the storage lesions can be roughly classified into two root causes: i) metabolite accumulation/depletion, the target of various interventions (additive solutions) developed since the inception of blood banking; and ii) oxidative damages, which have been reported for decades but not addressed systemically until recently. Downstream physiological consequences of these storage lesions, derived mainly by in vitro studies, are described, and further potential links to clinical consequences are discussed. Interventions to postpone the onset and mitigate the extent of the storage lesion development are briefly reviewed. In addition, we briefly discuss the results from recent randomised controlled trials on the age of stored blood and clinical outcomes of transfusion.

RevDate: 2019-01-24

Patthy L (2019)

Exon skipping-rich transcriptomes of animals reflect the significance of exon-shuffling in metazoan proteome evolution.

Biology direct, 14(1):2 pii:10.1186/s13062-019-0231-3.

ᅟ: Animals are known to have higher rates of exon skipping than other eukaryotes. In a recent study, Grau-Bové et al. (Genome Biology 19:135, 2018) have used RNA-seq data across 65 eukaryotic species to investigate when and how this high prevalence of exon skipping evolved. They have found that bilaterian Metazoa have significantly increased exon skipping frequencies compared to all other eukaryotic groups and that exon skipping in nearly all animals, including non-bilaterians, is strongly enriched for frame-preserving events. The authors have hypothesized that "the increase of exon skipping rates in animals followed a two-step process. First, exon skipping in early animals became enriched for frame-preserving events. Second, bilaterian ancestors dramatically increased their exon skipping frequencies, likely driven by the interplay between a shift in their genome architectures towards more exon definition and recruitment of frame-preserving exon skipping events to functionally diversify their cell-specific proteomes." Here we offer a different explanation for the higher frequency of frame-preserving exon skipping in Metzoa than in all other eukaryotes. In our view these observations reflect the fact that the majority of multidomain proteins unique to metazoa and indispensable for metazoan type multicellularity were assembled by exon-shuffling from 'symmetrical' modules (i.e. modules flanked by introns of the same phase), whereas this type of protein evolution played a minor role in other groups of eukaryotes, including plants. The higher frequency of 'symmetrical' exons in Metazoan genomes provides an explanation for the enrichment for frame-preserving events since skipping or inclusion of 'symmetrical' modules during alternative splicing does not result in a reading-frame shift. REVIEWERS: This article was reviewed by Manuel Irimia, Ashish Lal and Erez Levanon. The reviewers were nominated by the Editorial Board.

RevDate: 2019-02-15

Russell SL (2019)

Transmission mode is associated with environment type and taxa across bacteria-eukaryote symbioses: a systematic review and meta-analysis.

FEMS microbiology letters, 366(3):.

Symbiotic associations between bacteria and eukaryotes exhibit a range of transmission strategies. The rates and distributions of transmission modes have not been thoroughly investigated across associations, despite their consequences on symbiont and host evolution. To address this empirically, I compiled data from the literature on bacteria-multicellular eukaryote associations for which transmission mode data was available. Of the total 528 analyzed symbioses, 21.2% were strictly horizontally transmitted, 36.0% exhibited some form of mixed mode transmission and 42.8% were strictly vertically transmitted. Controlling for phylogenetically independent symbiosis events revealed modes were approximately equally distributed among the 113 independent associations, at 32.1%+/-0.57% horizontal, 37.8%+/-1.4% mixed mode and 31.1%+/-1.3% vertical transmission. Binning symbioses by environment revealed an abundance of vertical transmission on land and a lack of it in aquatic environments. The naturally occurring uneven distribution of taxa among environments prevented controlling for host/symbiont phylogeny. However, the results were robust over a large number of independently evolved associations, suggesting that many vertically transmitted bacteria are capable of mixed mode transmission and barriers exist that reduce the rate of horizontal transmission events. Thus, both the environment type and host/symbiont taxa influence symbiont transmission mode evolution.

RevDate: 2019-03-18

Arun A, Coelho SM, Peters AF, et al (2019)

Convergent recruitment of TALE homeodomain life cycle regulators to direct sporophyte development in land plants and brown algae.

eLife, 8: pii:43101.

Three amino acid loop extension homeodomain transcription factors (TALE HD TFs) act as life cycle regulators in green algae and land plants. In mosses these regulators are required for the deployment of the sporophyte developmental program. We demonstrate that mutations in either of two TALE HD TF genes, OUROBOROS or SAMSARA, in the brown alga Ectocarpus result in conversion of the sporophyte generation into a gametophyte. The OUROBOROS and SAMSARA proteins heterodimerise in a similar manner to TALE HD TF life cycle regulators in the green lineage. These observations demonstrate that TALE-HD-TF-based life cycle regulation systems have an extremely ancient origin, and that these systems have been independently recruited to regulate sporophyte developmental programs in at least two different complex multicellular eukaryotic supergroups, Archaeplastida and Chromalveolata.

RevDate: 2019-01-23

Oxford JT, Reeck JC, MJ Hardy (2019)

Extracellular Matrix in Development and Disease.

International journal of molecular sciences, 20(1): pii:ijms20010205.

The evolution of multicellular metazoan organisms was marked by the inclusion of an extracellular matrix (ECM), a multicomponent, proteinaceous network between cells that contributes to the spatial arrangement of cells and the resulting tissue organization. [...].

RevDate: 2019-01-11

Li XG, Zhang WJ, Xiao X, et al (2018)

Pressure-Regulated Gene Expression and Enzymatic Activity of the Two Periplasmic Nitrate Reductases in the Deep-Sea Bacterium Shewanella piezotolerans WP3.

Frontiers in microbiology, 9:3173.

Shewanella species are widely distributed in marine environments, from the shallow coasts to the deepest sea bottom. Most Shewanella species possess two isoforms of periplasmic nitrate reductases (NAP-α and NAP-β) and are able to generate energy through nitrate reduction. However, the contributions of the two NAP systems to bacterial deep-sea adaptation remain unclear. In this study, we found that the deep-sea denitrifier Shewanella piezotolerans WP3 was capable of performing nitrate respiration under high hydrostatic pressure (HHP) conditions. In the wild-type strain, NAP-β played a dominant role and was induced by both the substrate and an elevated pressure, whereas NAP-α was constitutively expressed at a relatively lower level. Genetic studies showed that each NAP system alone was sufficient to fully sustain nitrate-dependent growth and that both NAP systems exhibited substrate and pressure inducible expression patterns when the other set was absent. Biochemical assays further demonstrated that NAP-α had a higher tolerance to elevated pressure. Collectively, we report for the first time the distinct properties and contributions of the two NAP systems to nitrate reduction under different pressure conditions. The results will shed light on the mechanisms of bacterial HHP adaptation and nitrogen cycling in the deep-sea environment.

RevDate: 2019-01-10

Huitzil S, Sandoval-Motta S, Frank A, et al (2018)

Modeling the Role of the Microbiome in Evolution.

Frontiers in physiology, 9:1836.

There is undeniable evidence showing that bacteria have strongly influenced the evolution and biological functions of multicellular organisms. It has been hypothesized that many host-microbial interactions have emerged so as to increase the adaptive fitness of the holobiont (the host plus its microbiota). Although this association has been corroborated for many specific cases, general mechanisms explaining the role of the microbiota in the evolution of the host are yet to be understood. Here we present an evolutionary model in which a network representing the host adapts in order to perform a predefined function. During its adaptation, the host network (HN) can interact with other networks representing its microbiota. We show that this interaction greatly accelerates and improves the adaptability of the HN without decreasing the adaptation of the microbial networks. Furthermore, the adaptation of the HN to perform several functions is possible only when it interacts with many different bacterial networks in a specialized way (each bacterial network participating in the adaptation of one function). Disrupting these interactions often leads to non-adaptive states, reminiscent of dysbiosis, where none of the networks the holobiont consists of can perform their respective functions. By considering the holobiont as a unit of selection and focusing on the adaptation of the host to predefined but arbitrary functions, our model predicts the need for specialized diversity in the microbiota. This structural and dynamical complexity in the holobiont facilitates its adaptation, whereas a homogeneous (non-specialized) microbiota is inconsequential or even detrimental to the holobiont's evolution. To our knowledge, this is the first model in which symbiotic interactions, diversity, specialization and dysbiosis in an ecosystem emerge as a result of coevolution. It also helps us understand the emergence of complex organisms, as they adapt more easily to perform multiple tasks than non-complex ones.

RevDate: 2019-01-07

Bowman JL, Briginshaw LN, SN Florent (2019)

Evolution and co-option of developmental regulatory networks in early land plants.

Current topics in developmental biology, 131:35-53.

Land plants evolved from an ancestral alga from which they inherited developmental and physiological characters. A key innovation of land plants is a life cycle with an alternation of generations, with both haploid gametophyte and diploid sporophyte generations having complex multicellular bodies. The origins of the developmental genetic programs patterning these bodies, whether inherited from an algal ancestor or evolved de novo, and whether programs were co-opted between generations, are largely open questions. We first provide a framework for land plant evolution and co-option of developmental regulatory pathways and then examine two cases in more detail.

RevDate: 2019-01-07

Hackenberg D, D Twell (2019)

The evolution and patterning of male gametophyte development.

Current topics in developmental biology, 131:257-298.

The reproductive adaptations of land plants have played a key role in their terrestrial colonization and radiation. This encompasses mechanisms used for the production, dispersal and union of gametes to support sexual reproduction. The production of small motile male gametes and larger immotile female gametes (oogamy) in specialized multicellular gametangia evolved in the charophyte algae, the closest extant relatives of land plants. Reliance on water and motile male gametes for sexual reproduction was retained by bryophytes and basal vascular plants, but was overcome in seed plants by the dispersal of pollen and the guided delivery of non-motile sperm to the female gametes. Here we discuss the evolutionary history of male gametogenesis in streptophytes (green plants) and the underlying developmental biology, including recent advances in bryophyte and angiosperm models. We conclude with a perspective on research trends that promise to deliver a deeper understanding of the evolutionary and developmental mechanisms of male gametogenesis in plants.

RevDate: 2019-01-07

Szövényi P, Waller M, A Kirbis (2019)

Evolution of the plant body plan.

Current topics in developmental biology, 131:1-34.

Land plants evolved about 470 million years ago or even earlier, in a biological crust-dominated terrestrial flora. The origin of land plants was probably one of the most significant events in Earth's history, which ultimately contributed to the greening of the terrestrial environment and opened up the way for the diversification of both plant and non-plant lineages. Fossil and phylogenetic evidence suggest that land plants have evolved from fresh-water charophycean algae, which were physiologically, genetically, and developmentally potentiated to make the transition to land. Since all land plants have biphasic life cycles, in contrast to the haplontic life cycle of Charophytes, the evolution of land plants was linked to the origin of a multicellular sporophytic phase. Land plants have evolved complex body plans in a way that overall complexity increased toward the tip of the land plant tree of life. Early forms were unbranched, with terminal sporangia and simple rhizoid rooting structures but without vasculature and leaves. Later on, branched forms with lateral sporangia appeared and paved the route for the evolution for indeterminacy. Finally, leaves and roots evolved to enable efficient nutrient transport to support a large plant body. The fossil record also suggests that almost all plant organs, such as leaves and roots, evolved multiple times independently over the course of land plant evolution. In this review, we summarize the current knowledge on the evolution of the land plant body plan by combining evidence of the fossil record, phylogenetics, and developmental biology.

RevDate: 2019-01-24
CmpDate: 2019-01-22

Murre C (2019)

Helix-loop-helix proteins and the advent of cellular diversity: 30 years of discovery.

Genes & development, 33(1-2):6-25.

Helix-loop-helix (HLH) proteins are dimeric transcription factors that control lineage- and developmental-specific gene programs. Genes encoding for HLH proteins arose in unicellular organisms >600 million years ago and then duplicated and diversified from ancestral genes across the metazoan and plant kingdoms to establish multicellularity. Hundreds of HLH proteins have been identified with diverse functions in a wide variety of cell types. HLH proteins orchestrate lineage specification, commitment, self-renewal, proliferation, differentiation, and homing. HLH proteins also regulate circadian clocks, protect against hypoxic stress, promote antigen receptor locus assembly, and program transdifferentiation. HLH proteins deposit or erase epigenetic marks, activate noncoding transcription, and sequester chromatin remodelers across the chromatin landscape to dictate enhancer-promoter communication and somatic recombination. Here the evolution of HLH genes, the structures of HLH domains, and the elaborate activities of HLH proteins in multicellular life are discussed.

RevDate: 2018-12-27

Tsitsekian D, Daras G, Alatzas A, et al (2018)

Comprehensive analysis of Lon proteases in plants highlights independent gene duplication events.

Journal of experimental botany pii:5260396 [Epub ahead of print].

The degradation of damaged proteins is essential for cell viability. Lon is a highly conserved ATP-dependent serine-lysine protease that maintains proteostasis. We performed a comparative genome-wide analysis to determine the evolutionary history of Lon proteases. Prokaryotes and unicellular eukaryotes retained a single Lon copy, whereas multicellular eukaryotes acquired a peroxisomal copy, in addition to the mitochondrial gene, to sustain the evolution of higher order organ structures. Land plants developed small Lon gene families. Despite the Lon2 peroxisomal paralog, Lon genes triplicated in the Arabidopsis lineage through sequential evolutionary events including whole-genome and tandem duplications. The retention of Lon1, Lon4, and Lon3 triplicates relied on their differential and even contrasting expression patterns, distinct subcellular targeting mechanisms, and functional divergence. Lon1 seems similar to the pre-duplication ancestral gene unit, whereas the duplication of Lon3 and Lon4 is evolutionarily recent. In the wider context of plant evolution, papaya is the only genome with a single ancestral Lon1-type gene. The evolutionary trend among plants is to acquire Lon copies with ambiguous pre-sequences for dual-targeting to mitochondria and chloroplasts, and a substrate recognition domain that deviates from the ancestral Lon1 type. Lon genes constitute a paradigm of dynamic evolution contributing to understanding the functional fate of gene duplicates.

RevDate: 2019-02-01

Måløy M, Måløy F, Lahoz-Beltrá R, et al (2019)

An extended Moran process that captures the struggle for fitness.

Mathematical biosciences, 308:81-104.

When a new type of individual appears in a stable population, the newcomer is typically not advantageous. Due to stochasticity, the new type can grow in numbers, but the newcomers can only become advantageous if they manage to change the environment in such a way that they increase their fitness. This dynamics is observed in several situations in which a relatively stable population is invaded by an alternative strategy, for instance the evolution of cooperation among bacteria, the invasion of cancer in a multicellular organism and the evolution of ideas that contradict social norms. These examples also show that, by generating different versions of itself, the new type increases the probability of winning the struggle for fitness. Our model captures the imposed cooperation whereby the first generation of newcomers dies while changing the environment such that the next generations become more advantageous.

RevDate: 2019-01-15

Denbo S, Aono K, Kai T, et al (2019)

Revision of the Capsaspora genome using read mating information adjusts the view on premetazoan genome.

Development, growth & differentiation, 61(1):34-42.

The genome sequences of unicellular holozoans, the closest relatives to animals, are shedding light on the evolution of animal multicellularity, shaping the genetic contents of the putative premetazoans. However, the assembly quality of the genomes remains poor compared to the major model organisms such as human and fly. Improving the assembly is critical for precise comparative genomics studies and further molecular biological studies requiring accurate sequence information such as enhancer analysis and genome editing. In this report, we present a new strategy to improve the assembly by fully exploiting the information of Illumina mate-pair reads. By visualizing the distance and orientation of the mapped read pairs, we could highlight the regions where possible assembly errors exist in the genome sequence of Capsaspora, a lineage of unicellular holozoans. Manual modification of these errors repaired 590 assembly problems in total and reassembled 84 supercontigs into 55. Our telomere prediction analysis using the read pairs containing the pan-eukaryotic telomere-like sequence identified at least 13 chromosomes. The resulting new assembly posed us a re-annotation of 112 genes, including 15 putative receptor protein tyrosine kinases. Our strategy thus provides a useful approach for improving assemblies of draft genomes, and the new Capsaspora genome offers us an opportunity to adjust the view on the genome of the unicellular animal ancestor.

RevDate: 2019-04-09

Ortega-Escalante JA, Kwok O, SM Miller (2019)

New Selectable Markers for Volvox carteri Transformation.

Protist, 170(1):52-63.

Volvox carteri is an excellent model for investigating the evolution of multicellularity and cell differentiation, and the rate of future progress with this system will depend on improved molecular genetic tools. Several selectable markers for nuclear transformation of V. carteri have been developed, including the nitrate reductase (nitA) gene, but it would be useful to have additional markers to multiplex transgenes in this species. To further facilitate molecular genetic analyses of V. carteri, we developed two new selectable markers that provide rapid, easily selected, and stable resistance to the antibiotics hygromycin and blasticidin. We generated constructs with Volvox-specific regulatory sequences and codon-optimized hygromycin (VcHyg) and blasticidin (VcBlast) resistance genes from Coccidioides posadasii and Bacillus cereus, respectively. With these constructs, transformants were obtained via biolistic bombardment at rates of 0.5-13 per million target cells bombarded. Antibiotic-resistant survivors were readily isolated 7days post bombardment. VcHyg and VcBlast transgenes and transcripts were detected in transformants. Co-transformation rates using the VcHyg or VcBlast markers with unselected genes were comparable to those obtained with nitA. These results indicate that the pVcHyg and pVcBlast plasmids are highly efficient and convenient for transforming and co-transforming a broad range of V. carteri strains.

RevDate: 2019-02-09

Chen Y, Ikeda K, Yoneshiro T, et al (2019)

Thermal stress induces glycolytic beige fat formation via a myogenic state.

Nature, 565(7738):180-185.

Environmental cues profoundly affect cellular plasticity in multicellular organisms. For instance, exercise promotes a glycolytic-to-oxidative fibre-type switch in skeletal muscle, and cold acclimation induces beige adipocyte biogenesis in adipose tissue. However, the molecular mechanisms by which physiological or pathological cues evoke developmental plasticity remain incompletely understood. Here we report a type of beige adipocyte that has a critical role in chronic cold adaptation in the absence of β-adrenergic receptor signalling. This beige fat is distinct from conventional beige fat with respect to developmental origin and regulation, and displays enhanced glucose oxidation. We therefore refer to it as glycolytic beige fat. Mechanistically, we identify GA-binding protein α as a regulator of glycolytic beige adipocyte differentiation through a myogenic intermediate. Our study reveals a non-canonical adaptive mechanism by which thermal stress induces progenitor cell plasticity and recruits a distinct form of thermogenic cell that is required for energy homeostasis and survival.

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RJR Experience and Expertise

Researcher

Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.

Educator

Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.

Administrator

Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.

Technologist

Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.

Publisher

While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.

Speaker

Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.

Facilitator

Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.

Designer

Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

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Curriculum Vitae for R J Robbins

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