The Experts below are selected from a list of 141714 Experts worldwide ranked by ideXlab platform
Armen Y Mulkidjanian - One of the best experts on this subject based on the ideXlab platform.
-
on the Origin of Life in the zinc world 2 validation of the hypothesis on the photosynthesizing zinc sulfide edifices as cradles of Life on earth
Biology Direct, 2009Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:The accompanying article (A.Y. Mulkidjanian, Biology Direct 4:26) puts forward a detailed hypothesis on the role of zinc sulfide (ZnS) in the Origin of Life on Earth. The hypothesis suggests that Life emerged within compartmentalized, photosynthesizing ZnS formations of hydrothermal Origin (the Zn world), assembled in sub-aerial settings on the surface of the primeval Earth. If Life started within photosynthesizing ZnS compartments, it should have been able to evolve under the conditions of elevated levels of Zn2+ ions, byproducts of the ZnS-mediated photosynthesis. Therefore, the Zn world hypothesis leads to a set of testable predictions regarding the specific roles of Zn2+ ions in modern organisms, particularly in RNA and protein structures related to the procession of RNA and the "evolutionarily old" cellular functions. We checked these predictions using publicly available data and obtained evidence suggesting that the development of the primeval Life forms up to the stage of the Last Universal Common Ancestor proceeded in zinc-rich settings. Testing of the hypothesis has revealed the possible supportive role of manganese sulfide in the primeval photosynthesis. In addition, we demonstrate the explanatory power of the Zn world concept by elucidating several points that so far remained without acceptable rationalization. In particular, this concept implies a new scenario for the separation of Bacteria and Archaea and the Origin of Eukarya. The ability of the Zn world hypothesis to generate non-trivial veritable predictions and explain previously obscure items gives credence to its key postulate that the development of the first Life forms started within zinc-rich formations of hydrothermal Origin and was driven by solar UV irradiation. This concept implies that the geochemical conditions conducive to the Origin of Life may have persisted only as long as the atmospheric CO2 pressure remained above ca. 10 bar. This work envisions the first Earth biotopes as photosynthesizing and habitable areas of porous ZnS and MnS precipitates around primeval hot springs. Further work will be needed to provide details on the Life within these communities and to elucidate the primordial (bio)chemical reactions. This article was reviewed by Arcady Mushegian, Eugene Koonin, and Patrick Forterre. For the full reviews, please go to the Reviewers' reports section.
-
on the Origin of Life in the zinc world 2 validation of the hypothesis on the photosynthesizing zinc sulfide edifices as cradles of Life on earth
Biology Direct, 2009Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:Background: The accompanying article (A.Y. Mulkidjanian, Biology Direct 4:26) puts forward a detailed hypothesis on the role of zinc sulfide (ZnS) in the Origin of Life on Earth. The hypothesis suggests that Life emerged within compartmentalized, photosynthesizing ZnS formations of hydrothermal Origin (the Zn world), assembled in sub-aerial settings on the surface of the primeval Earth. Results: If Life started within photosynthesizing ZnS compartments, it should have been able to evolve under the conditions of elevated levels of Zn2+ ions, byproducts of the ZnS-mediated photosynthesis. Therefore, the Zn world hypothesis leads to a set of testable predictions regarding the specific roles of Zn 2+ ions in modern organisms, particularly in RNA and protein structures related to the procession of RNA and the "evolutionarily old" cellular functions. We checked these predictions using publicly available data and obtained evidence suggesting that the development of the primeval Life forms up to the stage of the Last Universal Common Ancestor proceeded in zinc-rich settings. Testing of the hypothesis has revealed the possible supportive role of manganese sulfide in the primeval photosynthesis. In addition, we demonstrate the explanatory power of the Zn world concept by elucidating several points that so far remained without acceptable rationalization. In particular, this concept implies a new scenario for the separation of Bacteria and Archaea and the Origin of Eukarya. Conclusion: The ability of the Zn world hypothesis to generate non-trivial veritable predictions and explain previously obscure items gives credence to its key postulate that the development of the first Life forms started within zinc-rich formations of hydrothermal Origin and was driven by solar UV irradiation. This concept implies that the geochemical conditions conducive to the Origin of Life may have persisted only as long as the atmospheric CO2 pressure remained above ca. 10 bar. This work envisions the first Earth biotopes as photosynthesizing and habitable areas of porous ZnS and MnS precipitates around primeval hot springs. Further work will be needed to provide details on the Life within these communities and to elucidate the primordial (bio)chemical reactions.
-
on the Origin of Life in the zinc world 1 photosynthesizing porous edifices built of hydrothermally precipitated zinc sulfide as cradles of Life on earth
Biology Direct, 2009Co-Authors: Armen Y MulkidjanianAbstract:Background: The complexity of the problem of the Origin of Life has spawned a large number of possible evolutionary scenarios. Their number, however, can be dramatically reduced by the simultaneous consideration of various bioenergetic, physical, and geological constraints. Results: This work puts forward an evolutionary scenario that satisfies the known constraints by proposing that Life on Earth emerged, powered by UV-rich solar radiation, at photosynthetically active porous edifices made of precipitated zinc sulfide (ZnS) similar to those found around modern deep-sea hydrothermal vents. Under the high pressure of the primeval, carbon dioxide-dominated atmosphere ZnS could precipitate at the surface of the first continents, within reach of solar light. It is suggested that the ZnS surfaces (1) used the solar radiation to drive carbon dioxide reduction, yielding the building blocks for the first biopolymers, (2) served as templates for the synthesis of longer biopolymers from simpler building blocks, and (3) prevented the first biopolymers from photo-dissociation, by absorbing from them the excess radiation. In addition, the UV light may have favoured the selective enrichment of photostable, RNA-like polymers. Falsification tests of this hypothesis are described in the accompanying article (A.Y. Mulkidjanian, M.Y. Galperin, Biology Direct 2009, 4:27). Conclusion: The suggested "Zn world" scenario identifies the geological conditions under which photosynthesizing ZnS edifices of hydrothermal Origin could emerge and persist on primordial Earth, includes a mechanism of the transient storage and utilization of solar light for the production of diverse organic compounds, and identifies the driving forces and selective factors that could have promoted the transition from the first simple, photostable polymers to more complex living organisms.
-
physico chemical and evolutionary constraints for the formation and selection of first biopolymers towards the consensus paradigm of the abiogenic Origin of Life
ChemInform, 2007Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:During the last two decades, the common school of thought has split into two, so that the problem of the Origin of Life is tackled in the framework of either the 'replication first' paradigm or the 'metabolism first' scenario. The first paradigm suggests that the Life started from the spontaneous emergence of the first, supposedly RNA-based 'replicators' and considers in much detail their further evolution in the so-called 'RNA world'. The alternative hypothesis of 'metabolism first' derives the Life from increasingly complex autocatalytic chemical cycles. In this work, we emphasize the role of selection during the pre-biological stages of evolution and focus on the constraints that are imposed by physical, chemical, and biological laws. We try to demonstrate that the 'replication first' and 'metabolism first' hypotheses complement, rather than contradict, each other. We suggest that Life on Earth has started from a 'metabolism-driven replication'; the suggested scenario might serve as a consensus scheme in the framework of which the molecular details of Origin of Life can be further elaborated. The key feature of the scenario is the participation of the UV irradiation both as driving and selecting forces during the earlier stages of evolution.
Helen Greenwood Hansma - One of the best experts on this subject based on the ideXlab platform.
-
possible Origin of Life between mica sheets
Journal of Theoretical Biology, 2010Co-Authors: Helen Greenwood HansmaAbstract:The mica hypothesis is a new hypothesis about how Life might have Originated. The mica hypothesis provides simple solutions to many basic questions about the Origins of Life. In the mica hypothesis, the spaces between mica sheets functioned as the earliest cells. These ‘cells’ between mica sheets are filled with potassium ions, and they provide an environment in which: polymer entropy is low; cyclic wetting and drying can occur; molecules can evolve in isolated spaces and also migrate and ligate to form larger molecules. The mica hypothesis also proposes that mechanical energy (work) is a major energy source that could have been used on many length scales to form covalent bonds, to alter polymer conformations, and to bleb daughter cells off protocells. The mica hypothesis is consistent with many other Origins hypotheses, including the RNA, lipid, and metabolic ‘worlds’. Therefore the mica hypothesis has the potential to unify Origins hypotheses, such that different molecular components and systems could simultaneously evolve in the spaces between mica sheets.
-
possible Origin of Life between mica sheets
Biophysical Journal, 2010Co-Authors: Helen Greenwood HansmaAbstract:Many problems with the Origin of Life are solved by the hypothesis that Life emerged between mica sheets. Ancient natural “books” of mica sheets provided secure nano-environments, endless energy sources, confinement chemistry effects, huge entropy reductions, and grids of anionic mineral sites bridged by exchangeable potassium ions (K+).The following scenario is proposed:Simple mechanical Work provided energy for covalent bond formation by mechanochemistry. Solar energy cycles and water movements powered up-and-down movements of mica sheets. A carbon-carbon bond's energy at room temperature is comparable to 6 nanoNewtons of force, moving 1 Angstrom in distance (Figure).Mica's up-and-down movements pressed on protocells, blebbing off ‘daughter’protocells. Blebbing-off has been observed in wall-less L-form bacteria and is proposed to be a remnant of the earliest cell divisions (Leaver, Nature09).Fluid percolated into and out of spaces between mica sheets, providing cycles of wetting and drying that favor the polymerization of amino acids.The discovery of Intrinsically Disordered Proteins (IDP) turns the protein structure-function dogma upside down, because individual IDPs can assume many transient structures and perform many functions (Dunker, JMolecGraphicsModelling2001). Prebiotic peptides, crowded at the edges of mica sheets, could have had simple functions.View Large Image | View Hi-Res Image | Download PowerPoint Slide
Nick Lane - One of the best experts on this subject based on the ideXlab platform.
-
promotion of protocell self assembly from mixed amphiphiles at the Origin of Life
Nature Ecology and Evolution, 2019Co-Authors: Sean F Jordan, Hanadi Rammu, I N Zheludev, Andrew M Hartley, Amandine Marechal, Nick LaneAbstract:Vesicles formed from single-chain amphiphiles (SCAs) such as fatty acids probably played an important role in the Origin of Life. A major criticism of the hypothesis that Life arose in an early ocean hydrothermal environment is that hot temperatures, large pH gradients, high salinity and abundant divalent cations should preclude vesicle formation. However, these arguments are based on model vesicles using 1–3 SCAs, even though Fischer–Tropsch-type synthesis under hydrothermal conditions produces a wide array of fatty acids and 1-alkanols, including abundant C10–C15 compounds. Here, we show that mixtures of these C10–C15 SCAs form vesicles in aqueous solutions between pH ~6.5 and >12 at modern seawater concentrations of NaCl, Mg2+ and Ca2+. Adding C10 isoprenoids improves vesicle stability even further. Vesicles form most readily at temperatures of ~70 °C and require salinity and strongly alkaline conditions to self-assemble. Thus, alkaline hydrothermal conditions not only permit protocell formation at the Origin of Life but actively favour it.
-
Acetyl Phosphate as a Primordial Energy Currency at the Origin of Life
Origins of Life and Evolution of Biospheres, 2018Co-Authors: Alexandra Whicher, Barry Herschy, Eloi Camprubí, Silvana Pinna, Nick LaneAbstract:Metabolism is primed through the formation of thioesters via acetyl CoA and the phosphorylation of substrates by ATP. Prebiotic equivalents such as methyl thioacetate and acetyl phosphate have been proposed to catalyse analogous reactions at the Origin of Life, but their propensity to hydrolyse challenges this view. Here we show that acetyl phosphate (AcP) can be synthesised in water within minutes from thioacetate (but not methyl thioacetate) under ambient conditions. AcP is stable over hours, depending on temperature, pH and cation content, giving it an ideal poise between stability and reactivity. We show that AcP can phosphorylate nucleotide precursors such as ribose to ribose-5-phosphate and adenosine to adenosine monophosphate, at modest (~2%) yield in water, and at a range of pH. AcP can also phosphorylate ADP to ATP in water over several hours at 50 °C. But AcP did not promote polymerization of either glycine or AMP. The amino group of glycine was preferentially acetylated by AcP, especially at alkaline pH, hindering the formation of polypeptides. AMP formed small stacks of up to 7 monomers, but these did not polymerise in the presence of AcP in aqueous solution. We conclude that AcP can phosphorylate biologically meaningful substrates in a manner analogous to ATP, promoting the Origins of metabolism, but is unlikely to have driven polymerization of macromolecules such as polypeptides or RNA in free solution. This is consistent with the idea that a period of monomer (cofactor) catalysis preceded the emergence of polymeric enzymes or ribozymes at the Origin of Life.
-
iron catalysis at the Origin of Life
Iubmb Life, 2017Co-Authors: Eloi Camprubí, Sean F Jordan, Rafaela Vasiliadou, Nick LaneAbstract:Iron-sulphur proteins are ancient and drive fundamental processes in cells, notably electron transfer and CO2 fixation. Iron-sulphur minerals with equivalent structures could have played a key role in the Origin of Life. However, the 'iron-sulphur world' hypothesis has had a mixed reception, with questions raised especially about the feasibility of a pyrites-pulled reverse Krebs cycle. Phylogenetics suggests that the earliest cells drove carbon and energy metabolism via the acetyl CoA pathway, which is also replete in Fe(Ni)S proteins. Deep differences between bacteria and archaea in this pathway obscure the ancestral state. These differences make sense if early cells depended on natural proton gradients in alkaline hydrothermal vents. If so, the acetyl CoA pathway diverged with the Origins of active ion pumping, and ancestral CO2 fixation might have been equivalent to methanogens, which depend on a membrane-bound NiFe hydrogenase, energy converting hydrogenase. This uses the proton-motive force to reduce ferredoxin, thence CO2 . The mechanism suggests that pH could modulate reduction potential at the active site of the enzyme, facilitating the difficult reduction of CO2 by H2 . This mechanism could be generalised under abiotic conditions so that steep pH differences across semi-conducting Fe(Ni)S barriers drives not just the first steps of CO2 fixation to C1 and C2 organics such as CO, CH3 SH and CH3 COSH, but a series of similar carbonylation and hydrogenation reactions to form longer chain carboxylic acids such as pyruvate, oxaloacetate and α-ketoglutarate, as in the incomplete reverse Krebs cycle found in methanogens. We suggest that the closure of a complete reverse Krebs cycle, by regenerating acetyl CoA directly, displaced the acetyl CoA pathway from many modern groups. A later reliance on acetyl CoA and ATP eliminated the need for the proton-motive force to drive most steps of the reverse Krebs cycle. © 2017 IUBMB Life, 69(6):373-381, 2017.
-
the Origin of Life in alkaline hydrothermal vents
AGU Fall Meeting Abstracts, 2016Co-Authors: Victor Sojo, Barry Herschy, Alexandra Whicher, Eloi Camprubí, Nick LaneAbstract:Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of Life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea.
-
How did LUCA make a living? Chemiosmosis in the Origin of Life.
BioEssays : news and reviews in molecular cellular and developmental biology, 2010Co-Authors: Nick Lane, John F. Allen, William MartinAbstract:Despite thermodynamic, bioenergetic and phylogenetic failings, the 81-year-old concept of primordial soup remains central to mainstream thinking on the Origin of Life. But soup is homogeneous in pH and redox potential, and so has no capacity for energy coupling by chemiosmosis. Thermodynamic constraints make chemiosmosis strictly necessary for carbon and energy metabolism in all free-living chemotrophs, and presumably the first free-living cells too. Proton gradients form naturally at alkaline hydrothermal vents and are viewed as central to the Origin of Life. Here we consider how the earliest cells might have harnessed a geochemically created proton-motive force and then learned to make their own, a transition that was necessary for their escape from the vents. Synthesis of ATP by chemiosmosis today involves generation of an ion gradient by means of vectorial electron transfer from a donor to an acceptor. We argue that the first donor was hydrogen and the first acceptor CO2.
Michael Y Galperin - One of the best experts on this subject based on the ideXlab platform.
-
on the Origin of Life in the zinc world 2 validation of the hypothesis on the photosynthesizing zinc sulfide edifices as cradles of Life on earth
Biology Direct, 2009Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:The accompanying article (A.Y. Mulkidjanian, Biology Direct 4:26) puts forward a detailed hypothesis on the role of zinc sulfide (ZnS) in the Origin of Life on Earth. The hypothesis suggests that Life emerged within compartmentalized, photosynthesizing ZnS formations of hydrothermal Origin (the Zn world), assembled in sub-aerial settings on the surface of the primeval Earth. If Life started within photosynthesizing ZnS compartments, it should have been able to evolve under the conditions of elevated levels of Zn2+ ions, byproducts of the ZnS-mediated photosynthesis. Therefore, the Zn world hypothesis leads to a set of testable predictions regarding the specific roles of Zn2+ ions in modern organisms, particularly in RNA and protein structures related to the procession of RNA and the "evolutionarily old" cellular functions. We checked these predictions using publicly available data and obtained evidence suggesting that the development of the primeval Life forms up to the stage of the Last Universal Common Ancestor proceeded in zinc-rich settings. Testing of the hypothesis has revealed the possible supportive role of manganese sulfide in the primeval photosynthesis. In addition, we demonstrate the explanatory power of the Zn world concept by elucidating several points that so far remained without acceptable rationalization. In particular, this concept implies a new scenario for the separation of Bacteria and Archaea and the Origin of Eukarya. The ability of the Zn world hypothesis to generate non-trivial veritable predictions and explain previously obscure items gives credence to its key postulate that the development of the first Life forms started within zinc-rich formations of hydrothermal Origin and was driven by solar UV irradiation. This concept implies that the geochemical conditions conducive to the Origin of Life may have persisted only as long as the atmospheric CO2 pressure remained above ca. 10 bar. This work envisions the first Earth biotopes as photosynthesizing and habitable areas of porous ZnS and MnS precipitates around primeval hot springs. Further work will be needed to provide details on the Life within these communities and to elucidate the primordial (bio)chemical reactions. This article was reviewed by Arcady Mushegian, Eugene Koonin, and Patrick Forterre. For the full reviews, please go to the Reviewers' reports section.
-
on the Origin of Life in the zinc world 2 validation of the hypothesis on the photosynthesizing zinc sulfide edifices as cradles of Life on earth
Biology Direct, 2009Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:Background: The accompanying article (A.Y. Mulkidjanian, Biology Direct 4:26) puts forward a detailed hypothesis on the role of zinc sulfide (ZnS) in the Origin of Life on Earth. The hypothesis suggests that Life emerged within compartmentalized, photosynthesizing ZnS formations of hydrothermal Origin (the Zn world), assembled in sub-aerial settings on the surface of the primeval Earth. Results: If Life started within photosynthesizing ZnS compartments, it should have been able to evolve under the conditions of elevated levels of Zn2+ ions, byproducts of the ZnS-mediated photosynthesis. Therefore, the Zn world hypothesis leads to a set of testable predictions regarding the specific roles of Zn 2+ ions in modern organisms, particularly in RNA and protein structures related to the procession of RNA and the "evolutionarily old" cellular functions. We checked these predictions using publicly available data and obtained evidence suggesting that the development of the primeval Life forms up to the stage of the Last Universal Common Ancestor proceeded in zinc-rich settings. Testing of the hypothesis has revealed the possible supportive role of manganese sulfide in the primeval photosynthesis. In addition, we demonstrate the explanatory power of the Zn world concept by elucidating several points that so far remained without acceptable rationalization. In particular, this concept implies a new scenario for the separation of Bacteria and Archaea and the Origin of Eukarya. Conclusion: The ability of the Zn world hypothesis to generate non-trivial veritable predictions and explain previously obscure items gives credence to its key postulate that the development of the first Life forms started within zinc-rich formations of hydrothermal Origin and was driven by solar UV irradiation. This concept implies that the geochemical conditions conducive to the Origin of Life may have persisted only as long as the atmospheric CO2 pressure remained above ca. 10 bar. This work envisions the first Earth biotopes as photosynthesizing and habitable areas of porous ZnS and MnS precipitates around primeval hot springs. Further work will be needed to provide details on the Life within these communities and to elucidate the primordial (bio)chemical reactions.
-
physico chemical and evolutionary constraints for the formation and selection of first biopolymers towards the consensus paradigm of the abiogenic Origin of Life
ChemInform, 2007Co-Authors: Armen Y Mulkidjanian, Michael Y GalperinAbstract:During the last two decades, the common school of thought has split into two, so that the problem of the Origin of Life is tackled in the framework of either the 'replication first' paradigm or the 'metabolism first' scenario. The first paradigm suggests that the Life started from the spontaneous emergence of the first, supposedly RNA-based 'replicators' and considers in much detail their further evolution in the so-called 'RNA world'. The alternative hypothesis of 'metabolism first' derives the Life from increasingly complex autocatalytic chemical cycles. In this work, we emphasize the role of selection during the pre-biological stages of evolution and focus on the constraints that are imposed by physical, chemical, and biological laws. We try to demonstrate that the 'replication first' and 'metabolism first' hypotheses complement, rather than contradict, each other. We suggest that Life on Earth has started from a 'metabolism-driven replication'; the suggested scenario might serve as a consensus scheme in the framework of which the molecular details of Origin of Life can be further elaborated. The key feature of the scenario is the participation of the UV irradiation both as driving and selecting forces during the earlier stages of evolution.
Michael J Russell - One of the best experts on this subject based on the ideXlab platform.
-
beating the acetyl coenzyme a pathway to the Origin of Life
Philosophical Transactions of the Royal Society B, 2013Co-Authors: Wolfgang Nitschke, Michael J RussellAbstract:Attempts to draft plausible scenarios for the Origin of Life have in the past mainly built upon palaeogeochemical boundary conditions while, as detailed in a companion article in this issue, frequently neglecting to comply with fundamental thermodynamic laws. Even if demands from both palaeogeochemistry and thermodynamics are respected, then a plethora of strongly differing models are still conceivable. Although we have no guarantee that Life at its Origin necessarily resembled biology in extant organisms, we consider that the only empirical way to deduce how Life may have emerged is by taking the stance of assuming continuity of biology from its inception to the present day. Building upon this conviction, we have assessed extant types of energy and carbon metabolism for their appropriateness to conditions probably pertaining in those settings of the Hadean planet that fulfil the thermodynamic requirements for Life to come into being. Wood–Ljungdahl (WL) pathways leading to acetyl CoA formation are excellent candidates for such primordial metabolism. Based on a review of our present understanding of the biochemistry and biophysics of acetogenic, methanogenic and methanotrophic pathways and on a phylogenetic analysis of involved enzymes, we propose that a variant of modern methanotrophy is more likely than traditional WL systems to date back to the Origin of Life. The proposed model furthermore better fits basic thermodynamic demands and palaeogeochemical conditions suggested by recent results from extant alkaline hydrothermal seeps.
-
hydrothermal vents and the Origin of Life
Nature Reviews Microbiology, 2008Co-Authors: William Martin, John A Baross, Deborah S Kelley, Michael J RussellAbstract:Hydrothermal vent systems, which can support Life in the absence of photosynthesis, are today inhabited by animals that form symbioses with lithoautotrophic microorganisms from which they obtain chemical energy. These hydrothermal systems might resemble the earliest microbial ecosystems on the Earth. Here, Martin, Baross, Kelley and Russell review how understanding these complex systems might inform our understanding of the Origins of Life itself. Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. There are striking parallels between the chemistry of the H2–CO2 redox couple that is present in hydrothermal systems and the core energy metabolic reactions of some modern prokaryotic autotrophs. The biochemistry of these autotrophs might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of Life. Hydrothermal vents thus unite microbiology and geology to breathe new Life into research into one of biology's most important questions — what is the Origin of Life?
