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The RNA-binding S1 domain is a β-barrel with a highly conserved RNA-binding site on its surface. This domain is an important part of the structures of different bacterial, archaeal, and eukaryotic proteins. A distinctive feature of the S1 domain is multiple presences (structural repeats) in proteins and protein complexes. Here, we have analyzed all available protein sequences in the UniProt database to obtain data on the distribution of bacterial, eukaryotic and archaeal proteins containing the S1 domain. Mainly, the S1 domain is found in bacterial proteins with the number of domains varying from one to eight. Eukaryotic proteins contain from one to fifteen S1 domains, while in archaeal proteins, only one S1 domain is identified. Analysis of eukaryotic proteins containing S1 domains revealed a group of chloroplast S1 ribosomal proteins (ChRpS1) with characteristic properties of bacterial S1 ribosomal proteins (RpS1) from the Cyanobacteria. Also, in a separate group, chloroplast and mitochondrial elongation factor Ts containing two S1 structural domains were assigned. For mitochondrial elongation factor Ts, the features of S1 in comparison with the RpS1 from Cyanobacteria phylum and the Alphaproteobacteria class were revealed. The data obtained allow us to consider the S1 domain as one of the evolutionary markers of the symbiogenesis of bacterial and eukaryotic organisms. [ABSTRACT FROM AUTHOR]

Symbiogenesis has been systematically exploited to understand consciousness as the aggregate of our physiology. The Symbiogenic mechanism for assimilation of factors in the environment formulates the continuum from inside the cell to the Cosmos, both consciousness and cosmology complying with the Laws of Nature. Since Symbiogenesis is 'constructive', whereas eliminating what threatens us is 'destructive', why do we largely practice Symbiogenesis? Hypothetically, Symbiogenesis recursively simulates the monism of our origin, recognizing 'something bigger than ourselves'. That perspective explains many heretofore unexplained aspects of consciousness, such as mind, epigenetic inheritance, physiology, behaviors, social systems, mathematics, the Arts, from an a priori perspective. Moreover, there is an energetic continuum from Newtonian to Quantum Mechanics, opening up to a novel way of understanding the 'true nature of our being', not as 'materialism', but instead being the serial homeostatic control of energy. The latter is consistent with the spirit of Claude Bernard and Walter B. Cannon's perspectives on physiology. Such a paradigm shift is overdue, given that materialism is causing the destruction of the Earth and ourselves. [ABSTRACT FROM AUTHOR]

Inner membranes of mitochondria are extensively folded, forming cristae. The observed overall correlation between efficient eukaryotic ATP generation and the area of internal mitochondrial inner membranes both in unicellular organisms and metazoan tissues seems to explain why they evolved. However, the crucial use of molecular oxygen (O2) as final acceptor of the electron transport chain is still not sufficiently appreciated. O2 was an essential prerequisite for cristae development during early eukaryogenesis and could be the factor allowing cristae retention upon loss of mitochondrial ATP generation. Here I analyze illuminating bacterial and unicellular eukaryotic examples. I also discuss formative influences of intracellular O2 consumption on the evolution of the last eukaryotic common ancestor (LECA). These considerations bring about an explanation for the many genes coming from other organisms than the archaeon and bacterium merging at the start of eukaryogenesis. [ABSTRACT FROM AUTHOR]

There is a consensus that we are conscious of something greater than ourselves, as if we are derived from some other primordial set of principles. Classical or Newtonian physics is based on the Laws of Nature. Conversely, in a recent series of articles, it has been hypothesized that the cell was formed from lipid molecules submerged in the primordial ocean that covered the earth 100 million years after it formed. Since lipids are amphiphiles, with both a positively- and negatively-charged pole, the negatively-charged pole is miscible in water. Under the influence of earth's gravity, the lipid molecules stand up perpendicularly to the surface of the water, packing together until the negative charge neutralizes the Van der Waals force for surface tension, causing the lipid molecules to 'leap' into the micellar form as a sphere with a semi-permeable membrane. Particles in the water freely enter and exit such spheres based on mass action. Over time such protocells evolved Symbiogenesis, encountering factors that posed existential threats, assimilating them to form physiology to maintain homeostatic control. Importantly, when differentiated lung or bone cells are exposed to zero gravity, they lose their phenotypic identity in their evolved state, which has been interpreted as transiting from local to non-local consciousness. [ABSTRACT FROM AUTHOR]

This article presents the thesis that communication and its associated technologies, as a cultural mediation system, can be understood as a common good. To do this, the concept of the common good is reviewed and popular and scientific knowledge is woven together. Some of the conditions are identified to theorize communication from this new framework: cooperation, decolonization and deliberation. The risk of common goods is their administration in the search for private or proprietary benefits. Development as an economic drift that implies overexploitation, unlimited growth and private benefits, constitutes a tool of colonial inheritance that promotes social changes that do not affect the common good, benefiting an international elite that increasingly monopolizes resources. [ABSTRACT FROM AUTHOR]

Eukaryogenesis represented a major evolutionary transition that led to the emergence of complex cells from simpler ancestors. For several decades, the most accepted scenario involved the evolution of an independent lineage of proto-eukaryotes endowed with an endomembrane system, including a nuclear compartment, a developed cytoskeleton and phagocytosis, which engulfed the alphaproteobacterial ancestor of mitochondria. However, the recent discovery by metagenomic and cultural approaches of Asgard archaea, which harbour many genes in common with eukaryotes and are their closest relatives in phylogenomic trees, rather supports scenarios based on the symbiosis of one Asgard-like archaeon and one or more bacteria at the origin of the eukaryotic cell. Here, we review the recent discoveries that led to this conceptual shift, briefly evoking current models of eukaryogenesis and the challenges ahead to discriminate between them and to establish a detailed, plausible scenario that accounts for the evolution of eukaryotic traits from those of their prokaryotic ancestors.

This paper describes decades of research develop­ing a new type of corn (maize) cultivar that utilizes partnerships with seed-borne, bacterial endophytes to create environmentally friendly, nutritious corn that is better adapted to organic farming. Over time the project engaged and formed multiple, evolving networks of corn breeders and other scientists, organic farmers, nongovernmental organizations (NGOs), private companies, the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS), and state agricultural univer­sities in several states. It addressed and partly resolved the need for developing (a) yield-competi­tive hybrids with greater nutrient density (methio­nine and minerals), (b) better adapted inbreds for organic production conditions, and (c) reduced pollution from nitrogen fertilizers. The partnership approach taken also differs from usual top-down mechanistic breeding approaches in that the methods of breeding entailed holistic attention, learning, and respect for what turned out to be corn plants evolving in symbiogenesis with beneficial microbial partners. Initial studies indicate that the resulting corn from the program is competitive in yield but has better nutritional value. It obtains more of its nitrogen from microbial biomass and organic matter and nitrogen fixation than does conventional corn. Its performance partially depends on seed-borne plant/microbial partnerships. This corn continues to be developed at the Mandaamin Institute but is also being commercially introduced for testing by farmers.

This paper describes decades of research developing a new type of corn (maize) cultivar that utilizes partnerships with seed-borne, bacterial endophytes to create environmentally friendly, nutritious corn that is better adapted to organic farming. Over time the project engaged and formed multiple, evolving networks of corn breeders and other scientists, organic farmers, nongovernmental organizations (NGOs), private companies, the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS), and state agricultural universities in several states. It addressed and partly resolved the need for developing (a) yield-competitive hybrids with greater nutrient density (methionine and minerals), (b) better adapted inbreds for organic production conditions, and (c) reduced pollution from nitrogen fertilizers. The partnership approach taken also differs from usual top-down mechanistic breeding approaches in that the methods of breeding entailed holistic attention, learning, and respect for what turned out to be corn plants evolving in symbiogenesis with beneficial microbial partners. Initial studies indicate that the resulting corn from the program is competitive in yield but has better nutritional value. It obtains more of its nitrogen from microbial biomass and organic matter and nitrogen fixation than does conventional corn. Its performance partially depends on seed-borne plant/microbial partnerships. This corn continues to be developed at the Mandaamin Institute but is also being commercially introduced for testing by farmers. [ABSTRACT FROM AUTHOR]

The common presence of microbial communities (microbiotas) that form life-long associations with particular body sites of vertebrates are considered to represent symbiotic partnerships. These multi-organismal associations are different than ‘holobiont’ partnerships defined by Margulis which have restricted diversity and feature high fidelity, intergenerational transmission of symbionts. Comparison of the nutritional and physiological properties of germfree, defined microbiota, and conventional mice help to reveal the extent of the symbiosis between the vertebrate host and microbial communities of high diversity. The mouse-microbiota association is not obligate, but gut microbiota function enables additional energy harvest from the diet. This represents a major evolutionary innovation and therefore could be considered to be an example of symbiogenesis. However, this advantage is balanced by the expenditure of energy required to maintain structures and physiology that prevent invasion of murine tissues by the microbiota. Extrapolation of observations from gnotobiotes to humans helps to develop an appreciation of the human-gut microbiota relationship with emphasis on factors that may have assisted human survival. [ABSTRACT FROM AUTHOR]

Symsagittifera roscoffensis is a well-known member of the order Acoela that lives in symbiosis with the algae Tetraselmis convolutae during its adult stage. Its natural habitat is the eastern coast of the Atlantic, where at specific locations thousands of individuals can be found, mostly, lying in large pools on the surface of sand at low tide. As a member of the Acoela it has been thought as a proxy for ancestral bilaterian animals; however, its phylogenetic position remains still debated. In order to understand the basic structural characteristics of the acoel genome, we sequenced and assembled the genome of aposymbiotic species S. roscoffensis. The size of this genome was measured to be in the range of 910-940 Mb. Sequencing of the genome was performed using PacBio Hi-Fi technology. Hi-C and RNA-seq data were also generated to scaffold and annotate it. The resulting assembly is 1.1 Gb large (covering 118% of the estimated genome size) and highly continuous, with N50 scaffold size of 1.04 Mb. The repetitive fraction of the genome is 61%, of which 85% (half of the genome) are LTR retrotransposons. Genome-guided transcriptome assembly identified 34,493 genes, of which 29,351 are protein coding (BUSCO score 97.6%), and 30.2% of genes are spliced leader trans-spliced. The completeness of this genome suggests that it can be used extensively to characterize gene families and conduct accurate phylogenomic reconstructions. [ABSTRACT FROM AUTHOR]

Copyright of Er(r)go: Teoria, Literatura, Kultura is the property of Wydawnictwo Uniwersytetu Slaskiego and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Poyang Lake is the property of Journal of Poyang Lake Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Canadian-Armenian director Atom Egoyan's film about the Armenian genocide, Mount Ararat is more than a symbol; as the titular character, it assumes a dynamic role. Indeed, Mount Ararat has historically played a co-constitutive part in the production of Armenian identity. The Armenian genocide threatened to sever symbiogenesis, the process of becoming together, between the mountain and its people. This symbiogenesis is captured in Ararat, which shows members of the diaspora grappling with the difficulty of accessing the sacred mountain, as well as lost territories in western Armenia/eastern Turkey, conveying what this deterritorialization means to their lives as displaced Armenians living in Canada. Through his representation of the contested landscape around Mount Ararat, Egoyan demonstrates that attending to this symbiogenetic relationship has significant implications for thinking through questions of diaspora identity, redress, and truth in the aftermath of the Armenian genocide. [ABSTRACT FROM AUTHOR]

Embracing science but suggesting an alternate explanation for global warming, the essay provides a thermodynamic and historical perspective on eco-destruction. From a long-term evolutionary perspective, caution is raised about the repetition of human exceptionalism implied by the popular term “Anthropocene,” which hyperbolically frames humankind as the first organism in evolutionary history, and uniquely dangerous at that, to threaten global life. In fact, cyanobacteria preceded technological humanity, altering Earth's atmospheric composition orders of magnitude more than humanity has. The extreme resilience of Gaia, planetary life taken as an open thermodynamic system with environmentally regulative tendencies, has undergone dramatic changes in the past, such as the production of an oxygen-rich atmosphere. Genetically nimble life, recycling matter on a planetary level, has evolved means of tempering the tendency of organisms to exponentially reproduce. Ironically, these means, some which appear to have evolved to titrate hypergrowth in animal clades via senescence, have so far escaped ecologically rapacious humans. Thermodynamically, modern technological humanity, for all its self-regard as an intelligent life form, resembles a ravaging fire or intrinsically short-lived storm system. Long-term human persistence in the global ecosystem will require changes in our epistemology, economics, and ecology

To gain a full understanding of the relationship between climate change and physiology we must transcend the superficial Anthropic Principle, that we are ‘in’ this Universe, and enter the world of ‘Goldilocks’ who was seeking the ‘just right’ condition in the home of the three bears. What she was actually looking for was homeostasis, that balance that epitomizes all of Cosmology. It is the ‘equals’ sign in all balanced equations, whether it's physics, chemistry or biology. It represents the resolution of the Big Bang, which disrupted the Singularity thought to have pre-existed it, giving rise to asymmetries. We emulate that effort through Symbiogenesis - the assimilation of factors in the environment that have posed existential threats - as the means of evolution in response to climate change. Such a ‘true’ narrative is tantamount to gaining control of our runaway climate.

Copyright of Actas de Diseño is the property of Facultad de Diseno y Comunicacion, Fundacion Universidad de Palermo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, a review regarding the mechanics and evolution of mitochondrial fission appeared in Nature. Surprisingly, it stated authoritatively that the mitochondrial outer membrane, in contrast with the inner membrane of bacterial descent, was acquired from the host, presumably during uptake. However, it has been known for quite some time that this membrane was also derived from the Gram‐negative, alpha‐proteobacterium related precursor of present‐day mitochondria. The zombie idea of the host membrane still surrounding the endosymbiont is not only wrong, but more importantly, might hamper the proper conception of possible scenarios of eukaryogenesis. Why? Because it steers the imagination not only with regard to possible uptake mechanisms, but also regarding what went on before. Here I critically discuss both the evidence for the continuity of the bacterial outer membrane, the reasons for the persistence of the erroneous host membrane hypothesis and the wider implications of these misconceptions for the ideas regarding events occurring during the first steps towards the evolution of the eukaryotes and later major eukaryotic differentiations. I will also highlight some of the latest insights regarding different instances of endosymbiont evolution. [ABSTRACT FROM AUTHOR]

Recent human activity has profoundly transformed Earth biomes on a scale and at rates that are unprecedented. Given the central role of symbioses in ecosystem processes, functions, and services throughout the Earth biosphere, the impacts of human-driven change on symbioses are critical to understand. Symbioses are not merely collections of organisms, but co-evolved partners that arise from the synergistic combination and action of different genetic programs. They function with varying degrees of permanence and selection as emergent units with substantial potential for combinatorial and evolutionary innovation in both structure and function. Following an articulation of operational definitions of symbiosis and related concepts and characteristics of the Anthropocene, we outline a basic typology of anthropogenic change (AC) and a conceptual framework for how AC might mechanistically impact symbioses with select case examples to highlight our perspective. We discuss surprising connections between symbiosis and the Anthropocene, suggesting ways in which new symbioses could arise due to AC, how symbioses could be agents of ecosystem change, and how symbioses, broadly defined, of humans and "farmed" organisms may have launched the Anthropocene. We conclude with reflections on the robustness of symbioses to AC and our perspective on the importance of symbioses as ecosystem keystones and the need to tackle anthropogenic challenges as wise and humble stewards embedded within the system. [ABSTRACT FROM AUTHOR]

Mitochondria and plastids evolved from free-living bacteria, but are now considered integral parts of the eukaryotic species in which they live. Therefore, they are implicitly called by the same eukaryotic species name. Historically, mitochondria and plastids were known as “organelles”, even before their bacterial origin became fully established. However, since organelle evolution by endosymbiosis has become an established theory in biology, more and more endosymbiotic systems have been discovered that show various levels of host/symbiont integration. In this context, the distinction between “host/symbiont” and “eukaryote/organelle” systems is currently unclear. The criteria that are commonly considered are genetic integration (via gene transfer from the endosymbiont to the nucleus), cellular integration (synchronization of the cell cycles), and metabolic integration (the mutual dependency of the metabolisms). Here, I suggest that these criteria should be evaluated according to the resulting coupling of genetic recombination between individuals and congruence of effective population sizes, which determines if independent speciation is possible for either of the partners. I would like to call this aspect of integration “sexual symbiont integration”. If the partners lose their independence in speciation, I think that they should be considered one species. The partner who maintains its genetic recombination mechanisms and life cycle should then be the name giving “host”; the other one would be the organelle. Distinguishing between organelles and symbionts according to their sexual symbiont integration is independent of any particular mechanism or structural property of the endosymbiont/host system under investigation.

Endosymbiosis or symbiogenesis is a process where a cell hosts another cell that is acquired through phagocytosis or natural entry of the cell within its cytoplasm. Endosymbiosis has a profound effect on the survival of the host cell by conferring nutritional and/or biosynthetic advantage. Therefore, attempts of artificial endosymbiosis have become one of the most challenging projects in synthetic biology. In this paper, we review the process of endosymbiosis, its levels, requirements and mechanisms. We then review the unique cases of 'natural endosymbiosis'. Furthermore, we describe and evaluate the recent cases of attempted artificial endosymbiosis. Subsequently, we assess the potential barriers to the possibility of endosymbiosis of highly evolved cell types such as mammalian cells that are known for their high inflexibility towards hosting potentially even the most 'benign endosymbionts'. The paper concludes with possibilities and methodologies that may have not been evaluated or tried in the past, but may be used to increase the chance of artificial endosymbiosis of host cells such as those from mammalian origin that are not permissive to even benign endosymbionts. Artificial endosymbiosis is worth revisiting in this post-genomic, synthetic biology era because the tools and techniques currently available at our disposal have significantly advanced to make this grand challenge a possibility. [ABSTRACT FROM AUTHOR]

Various groups of proteobacteria and cyanobacteria, as well as unicellular algae capable of endosymbioses with eukaryotes, are addressed as the models for reconstruction of organellogenesis (transformation of symbiotic microbes into cellular organelles) as a major result of symbiogenesis—the evolution based on formation of integral hereditary systems by tightly interacting partners. Organellogenesis includes the following transitions: facultative non-inherited intracellular symbionts → obligatory inherited endocytobionts → genome-containing organelles → genome-free organelles. We have demonstrated that organellogenesis is accompanied by the loss of bacterial genetic individuality—the ability to maintain and express their own genomes, including their complete elimination. Comparative analysis of various groups of endosymbiotic bacteria showed that the major prerequisite for their transformation into organelles (primary organellogenesis) is high genomic plasticity expressed at the early stages of organellogenesis, under facultative or obligatory dependences on hosts. It is manifested as a directed change in genome architecture (transitions of unitary-type genomes to multicomponent- and reduced-type genomes), as well as in the export of functionally active genes into nonrelated organisms. These properties are characteristic for α-proteobacteria and cyanobacteria—the ancestors of mitochondria and plastids, but not for β- and γ-proteobacteria, Bacteroidetes and Firmicutes, which, although they include multiple endosymbiotic forms, have not been transformed into organelles. A convenient model for analyzing the secondary organellogenesis implemented by eukaryotic microorganisms is represented by dinoflagellates Symbiodinium (Alveolata), which (1) harbor chloroplasts derived from red algae and (2) develop intracellular symbioses with invertebrates behaving as their plastids. Reconstruction of organellogenesis allows us to address the early stages of organic evolution including the trade-off between metabolism and heredity, as well as between the RNA- or DNA-based genomes. [ABSTRACT FROM AUTHOR]

At the beginning of the 21st century we find a call for philosophers to join a new alliance: with artists and architects rather than linguists or physicists. In order to see the ecosystem, we need to switch concepts, look away from "nature" and move towards ambiance and hyperobjects. Along with this rehabilitation of Aristotle (by speculative realism and, more specifically, object-oriented ontology) comes a call for a fresh start as post-humanistic symbionts. These are proposals for alternatives to the catastrophic end of the short-lived drama of the Anthropocene. All this aids the here introduction of near-future hyperobjectivity. [ABSTRACT FROM AUTHOR]

Many theorists in recent years have been calling for evolutionary biology to move beyond the Modern Synthesis – the paradigm that has long provided the theoretical backbone for the discipline. Terms like "postmodern synthesis," "integrative synthesis," and "extended evolutionary synthesis" have been invoked by various critics in connection with the many recent developments that pose deep challenges – even contradictions – to the traditional model and underscore the need for an update, or a makeover. However, none of these critics, to this author's knowledge, has to date offered an explicit alternative that could provide a unifying theoretical paradigm for our vastly increased knowledge about living systems and the history of life on Earth (but see Noble 2015, 2017). This paper briefly summarizes the case against the Modern Synthesis and its many amendments over the years, and a new paradigm is proposed, called an "Inclusive Biological Synthesis," which, it is argued, can provide a more general framework for the biological sciences. The focus of this framework is the fundamental nature of life as a contingent dynamic process – an always at-risk "survival enterprise." The ongoing, inescapable challenge of earning a living in a given environmental context – biological survival and reproduction – presents an existential problem to which all biological phenomena can be related and comprehended. They and their "parts" can be analyzed in relation to ethologist Niko Tinbergen's four key questions. Some basic properties and guiding assumptions related to this alternative paradigm are also identified. • It is argued here that the time has come to replace the Modern Synthesis. • Many recent developments go beyond or contradict this venerable paradigm. • The case against the Modern Synthesis is briefly summarized. • An alternative called an "Inclusive Biological Synthesis" is proposed. • Tinbergen's four key questions are advanced as a common research agenda. [ABSTRACT FROM AUTHOR]

This article examines current efforts by the woman-led Lower North Shore Bioproducts Solidarity Coop on the northeastern coast of Québec, Canada to re-brand their region for sustainable economic growth. This cooperative is using the narrative tools of social media to counteract stories of decimation following the collapse of the fishing industry in the region in the 1990s. The goal of the Coop is to create jobs in the community through the production and export of local products made from wild berries and other plants. Through their creative use of Facebook and YouTube, narratives about the Lower North Shore are changing. The use of online platforms for sharing videos and stories allows the community to re-create itself through the lens of environmental stewardship rather than exploitation. These efforts can be seen as a form of feminist place-making. This photo-essay argues that using the discourse of terroir to re-brand the region for outside consumption has the dual possibilities of valuing non-invasive, seasonal fruit harvesting performed on a small scale by locals, and also opening the door to detrimental transformation of the land. Analyzing the deployment of the term terroir in this case will point to its ambiguous potential for sustainable development. This original artistic research, based on interviews and fieldwork conducted from 2013 to 2015, will be of interest to readers of Gender, Place & Culture for its focus on the efforts of women, many of whom are seniors, to re-present nature-cultures in a geographically remote coastal region. [ABSTRACT FROM AUTHOR]

Eukaryotic origins are inextricably linked with the arrival of a pre‐mitochondrion of alphaproteobacterial‐like ancestry. However, the nature of the "host" cell and the mode of entry are subject to heavy debate. It is becoming clear that the mutual adaptation of a relatively simple, archaeal host and the endosymbiont has been the defining influence at the beginning of the eukaryotic lineage; however, many still resist such symbiogenic models. In part 1, it is posited that a symbiotic stage before uptake ("pre‐symbiosis") seems essential to allow further metabolic integration of the two partners ending in endosymbiosis. Thus, the author argued against phagocytic mechanisms (in which the bacterium is prey or parasite) as the mode of entry. Such positions are still broadly unpopular. Here it is explained why. Evolutionary thinking, especially in the case of eukaryogenesis, is still dominated by anachronistic reasoning, in which highly derived protozoan organisms are seen as in some way representative of intermediate steps during eukaryotic evolution, hence poisoning the debate. This reasoning reflects a mind‐set that ignores that Darwinian evolution is a fundamentally historic process. Numerous examples of this kind of erroneous reasoning are given, and some basic precautions against its use are formulated. Also see the video abstract here https://youtu.be/ekqtNleVJpU [ABSTRACT FROM AUTHOR]

Eukaryotic origins are heavily debated. The author as well as others have proposed that they are inextricably linked with the arrival of a pre‐mitochondrion of alphaproteobacterial‐like ancestry, in a so‐called symbiogenic scenario. The ensuing mutual adaptation of archaeal host and endosymbiont seems to have been a defining influence during the processes leading to the last eukaryotic common ancestor. An unresolved question in this scenario deals with the means by which the bacterium ends up inside. Older hypotheses revolve around the application of known antagonistic interactions, the bacterium being prey or parasite. Here, in reviewing the field, the author argues that such models share flaws, hence making them less likely, and that a "pre‐symbiotic stage" would have eased ongoing metabolic integration. Based on this the author will speculate about the nature of the (endo) symbiosis that started eukaryotic evolution–in the context of bacterial entry being a relatively "early" event–and stress the differences between this uptake and subsequent ones. He will also briefly discuss how the mutual adaptation following the merger progressed and how many eukaryotic hallmarks can be understood in light of coadaptation. Also see the video abstract here https://youtu.be/ekqtNleVJpU [ABSTRACT FROM AUTHOR]

Eukaryotes are typically depicted as descendants of archaea, but their genomes are evolutionary chimeras with genes stemming from archaea and bacteria. Which prokaryotic heritage predominates? Here, we have clustered 19,050,992 protein sequences from 5,443 bacteria and 212 archaea with 3,420,731 protein sequences from 150 eukaryotes spanning six eukaryotic supergroups. By downsampling, we obtain estimates for the bacterial and archaeal proportions. Eukaryotic genomes possess a bacterial majority of genes. On average, the majority of bacterial genes is 56% overall, 53% in eukaryotes that never possessed plastids, and 61% in photosynthetic eukaryotic lineages, where the cyanobacterial ancestor of plastids contributed additional genes to the eukaryotic lineage. Intracellular parasites, which undergo reductive evolution in adaptation to the nutrient rich environment of the cells that they infect, relinquish bacterial genes for metabolic processes. Such adaptive gene loss is most pronounced in the human parasite Encephalitozoon intestinalis with 86% archaeal and 14% bacterial derived genes. The most bacterial eukaryote genome sampled is rice, with 67% bacterial and 33% archaeal genes. The functional dichotomy, initially described for yeast, of archaeal genes being involved in genetic information processing and bacterial genes being involved in metabolic processes is conserved across all eukaryotic supergroups. [ABSTRACT FROM AUTHOR]

The concept of a cosmic virosphere that serves as the repository of information for all life on Earth and throughout the Universe is discussed. Recent studies in geology, astronomy and biology point to an intimate connection between the evolution of life and a cosmic virosphere/biosphere. [ABSTRACT FROM AUTHOR]

Plants and animals have long been considered distinct kingdoms, yet here a 'plant-animal' is described. An extraordinary symbiosis in which neither organism can reproduce without the other, the fig tree (Ficus) provides the habitat for its exclusive pollinator: the fig wasp (Agaonidae). Characterising the 'fig-fig wasp holobiont' acknowledges, for the first time, 'plant-animal symbiogenesis'. [ABSTRACT FROM AUTHOR]