scholarly journals The Deep Rocky Biosphere: New Geomicrobiological Insights and Prospects

2021 ◽  
Vol 12 ◽  
Author(s):  
Hinako Takamiya ◽  
Mariko Kouduka ◽  
Yohey Suzuki
Keyword(s):  
Microbial Interactions ◽  
Radioactive Elements ◽  
Cell Level ◽  
High Iron Content ◽  
Microbial Life ◽  
Technological Advances ◽  
Energy Inputs ◽  
Microbial Proliferation ◽  
Rocky Habitats ◽  
Life On Earth

Rocks that react with liquid water are widespread but spatiotemporally limited throughout the solar system, except for Earth. Rock-forming minerals with high iron content and accessory minerals with high amounts of radioactive elements are essential to support rock-hosted microbial life by supplying organics, molecular hydrogen, and/or oxidants. Recent technological advances have broadened our understanding of the rocky biosphere, where microbial inhabitation appears to be difficult without nutrient and energy inputs from minerals. In particular, microbial proliferation in igneous rock basements has been revealed using innovative geomicrobiological techniques. These recent findings have dramatically changed our perspective on the nature and the extent of microbial life in the rocky biosphere, microbial interactions with minerals, and the influence of external factors on habitability. This study aimed to gather information from scientific and/or technological innovations, such as omics-based and single-cell level characterizations, targeting deep rocky habitats of organisms with minimal dependence on photosynthesis. By synthesizing pieces of rock-hosted life, we can explore the evo-phylogeny and ecophysiology of microbial life on Earth and the life’s potential on other planetary bodies.

scholarly journals Prospects for metazoan life in sub-glacial Antarctic lakes: the most extreme life on Earth?

2019 ◽  
Vol 18 (05) ◽  
pp. 416-419 ◽  
Author(s):  
Sven Thatje ◽  
Alastair Brown ◽  
Claus-Dieter Hillenbrand
Keyword(s):  
Hydrothermal Vents ◽  
Pure Water ◽  
Hydrothermal Activity ◽  
Microbial Life ◽  
Lake Vostok ◽  
Physico Chemical ◽  
Physiological Adaptations ◽  
Subglacial Lakes ◽  
Life On Earth ◽  
Harsh Conditions

AbstractAbout 400 subglacial lakes are known from Antarctica. The question of whether life unique of subglacial lakes exists has been paramount since their discovery. Despite frequent evidence of microbial life mostly from accretion ice, subglacial lakes are characterized by physiologically hostile conditions to metazoan life, as we know it. Pure water (salinity ≤0.4–1.2%), extreme cold (−3°C), high hydrostatic pressure, areas of limited or no oxygen availability and permanent darkness altogether require physiological adaptations to these harsh conditions. The record of gene sequences including some associated with hydrothermal vents does foster the idea of metazoan life in Lake Vostok. Here, we synthesize the physico-chemical environment surrounding sub-glacial lakes and potential sites of hydrothermal activity and advocate that the physico-chemical stability found at these sites may be the most likely sites for metazoan life to exist. The unique conditions presented by Lake Vostok may also offer an outlook on life to be expected in extra-terrestrial subglacial environments, such as on Jupiter's moon Europa or Saturn's moon Enceladus.

scholarly journals Pathways for abiotic organic synthesis at submarine hydrothermal fields

2015 ◽  
Vol 112 (25) ◽  
pp. 7668-7672 ◽  
Author(s):  
Jill M. McDermott ◽  
Jeffrey S. Seewald ◽  
Christopher R. German ◽  
Sean P. Sylva
Keyword(s):  
Organic Compounds ◽  
Organic Synthesis ◽  
Deep Sea ◽  
Hot Springs ◽  
Hydrothermal Systems ◽  
Deep Biosphere ◽  
Shallow Subsurface ◽  
Microbial Life ◽  
Abiotic Organic Synthesis ◽  
Life On Earth

Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

scholarly journals Mini-Review: Probing the limits of extremophilic life in extraterrestrial environment-simulated experiments

2012 ◽  
Vol 11 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Claudia A.S. Lage ◽  
Gabriel Z.L. Dalmaso ◽  
Lia C.R.S. Teixeira ◽  
Amanda G. Bendia ◽  
Ivan G. Paulino-Lima ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Microbial Life ◽  
Radiation Sources ◽  
Interesting Possibility ◽  
Terrestrial Environments ◽  
Radiation Resistant ◽  
Extraterrestrial Environment ◽  
Life On Earth ◽  
Micro Organisms ◽  
The Universe

AbstractAstrobiology is a relatively recent scientific field that seeks to understand the origin and dynamics of life in the Universe. Several hypotheses have been proposed to explain life in the cosmic context throughout human history, but only now, technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, such as carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are ubiquitous. How these compounds were combined to the point of originating cells and complex organisms is still to be unveiled by science. However, our 4.5 billion years old Solar system appeared in a 10 billion years old Universe. Thus, simple cells such as micro-organisms may have had time to form in planets older than ours or in other suitable places in the Universe. One hypothesis related to the appearance of life on Earth is called panspermia, which predicts that microbial life could have been formed in the Universe billions of years ago, travelling between planets, and inseminating units of life that could have become more complex in habitable planets such as Earth. A project designed to test the viability of extremophile micro-organisms exposed to simulated extraterrestrial environments is in progress at the Carlos Chagas Filho Institute of Biophysics (UFRJ, Brazil) to test whether microbial life could withstand inhospitable environments. Radiation-resistant (known or novel ones) micro-organisms collected from extreme terrestrial environments have been exposed (at synchrotron accelerators) to intense radiation sources simulating Solar radiation, capable of emitting radiation in a few hours equivalent to many years of accumulated doses. The results obtained in these experiments reveal an interesting possibility of the existence of microbial life beyond Earth.

scholarly journals Investigating temperature effects on coastal microbial populations and trophic interactions with 16S and 18S rRNA metabarcoding

2021 ◽  
Author(s):  
Sean R. Anderson ◽  
Margot Chisholm ◽  
Elizabeth L. Harvey
Keyword(s):  
Ecosystem Health ◽  
Microbial Interactions ◽  
Microbial Populations ◽  
Positive Interactions ◽  
Rrna Gene ◽  
Microbial Life ◽  
Cross Domain ◽  
Subtropical Estuary ◽  
Microbial Population Dynamics ◽  
The Impact

SummaryTemperature is a universal driver of microbial life, with rising sea surface temperatures expected to differentially influence the physiology, biodiversity, and distribution of bacteria and plankton. The impact of ocean warming on microbial interactions remains unclear, despite the importance of these relationships for ecosystem functioning. We employed weekly to monthly 18S and 16S rRNA gene amplicon metabarcoding over a full year (33 d) in a subtropical estuary, investigating microbial population dynamics and network interactions with respect to a temperature gradient (9–31°C). Certain microbes (e.g., Acidimicrobiia, Nitrososphaeria, and Syndiniales) increased in relative abundance with rising temperatures (Spearman ρ > 0.69), whereas other groups (e.g., Alpha- and Gammaproteobacteria, Bacillariophyta, and Dinophyceae) slightly decreased, became saturated, or remained stable. With network analysis, we observed an increase in 18S– 18S interactions in warm (23–31°C) vs. cold (<23°C) temperatures, largely involving Syndiniales, Bacillariophyta, and Dinophyceae ASVs. Bacteria ASVs were more connected to other microbes (higher degree and centrality) and became more prominent in the cold network, highlighted by well-established cross-domain relationships (e.g., diatom–bacteria) and positive interactions among bacteria (e.g., SAR11 and Rhodobacterales). These efforts highlight the types of interactions that may be more common under changing temperatures, with implications for modeling biogeochemistry and assessing ecosystem health.

scholarly journals Subseafloor basalts as fungal habitats

2012 ◽  
Vol 9 (2) ◽  
pp. 2277-2306 ◽  
Author(s):  
M. Ivarsson
Keyword(s):  
Morphological Characteristics ◽  
Microbial Life ◽  
Ocean Drilling ◽  
Potential Habitat ◽  
The Pacific ◽  
Fungal Hyphae ◽  
The Pacific Ocean ◽  
Life On Earth ◽  
Near Future ◽  
Deep Subseafloor

Abstract. The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, next to nothing is known about this deep, concealed biosphere. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (~50–200 μm in diameter) body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few μm:s to ∼20 μm in diameter) are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma, and probably still is. It is suggested that near future ocean drilling programs prioritize sampling of live species to better understand this concealed biosphere.

Current Research in Astrobiology

2021 ◽  
Author(s):  
Gratis Research
Keyword(s):  
Microbial Life ◽  
Form Of Life ◽  
Life On Earth

Because microorganisms are the most widespread form of life on earth and are capable of colonising almost any environment, scientists usually focus on microbial life in the field of astrobiology.

scholarly journals Acceleration of amino acid racemization by isovaline: possible implications for homochirality and biosignature search

2020 ◽  
Vol 19 (3) ◽  
pp. 276-282
Author(s):  
Stefan Fox ◽  
Annika Gspandl ◽  
Franziska M. Wenng
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Enantiomeric Excess ◽  
Terrestrial Planet ◽  
Microbial Life ◽  
Amino Acid Racemization ◽  
Geothermal Heating ◽  
Life On Mars ◽  
Volcanic Islands ◽  
Life On Earth

AbstractIn nature, abiotically formed amino acids are usually racemic. However, this is not true for the α,α-dialkyl amino acid isovaline (Iva), which has an L-enantiomeric excess in some specimens of carbonaceous meteorites. On the early Earth and Mars, such meteorites were sources of amino acids, including Iva. Therefore, a connection may exist between the possible chiral influence of non-racemic Iva and the origin of biological homochirality. On the surface of a young terrestrial planet, amino acids can be chemically altered in many ways. For example, high temperatures from geothermal heating can lead to racemization. Four billion years ago, active volcanism and volcanic islands provided suitable conditions for such reactions and perhaps even for early microbial life on Earth. In the current study, we investigated the influence of D- and L-Iva on the thermal racemization of L-alanine (L-Ala) and L-2-aminobutyric acid (L-Abu) in a simulated hot volcanic environment. The amino acids were intercalated in the clay mineral calcium montmorillonite (SAz-1). While Iva was resistant to racemization, partial racemization was observed for Ala and Abu after 8 weeks at 150°C. The experimental results – for example, accelerated racemization in the presence of Iva and different influences of the Iva enantiomers – suggest that the amino acid molecules interacted with each other, possibly in hydrogen-bonded dimers. Accelerated racemization of amino acids could have been an obstacle to the development of homochirality. Besides, it is also detrimental to the use of homochirality as a biosignature, for example, in the search for microbial life on Mars.

scholarly journals The Role of Biofilms in the Development and Dissemination of Microbial Resistance within the Food Industry

Foods ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 816 ◽  
Author(s):  
Efstathios Giaouris ◽  
Manuel Simões ◽  
Florence Dubois-Brissonnet
Keyword(s):  
Microbial Communities ◽  
Antimicrobial Agents ◽  
Resistance Mechanisms ◽  
Microbial Interactions ◽  
Food Hygiene ◽  
Adaptive Responses ◽  
Ongoing Research ◽  
Microbial Life ◽  
Diffusion Limitations

Biofilms are multicellular sessile microbial communities embedded in hydrated extracellular polymeric matrices. Their formation is common in microbial life in most environments, while those formed on food-processing surfaces are of considerable interest in the context of food hygiene. Biofilm cells express properties that are distinct from planktonic ones, in particular, notorious resistance to antimicrobial agents. Thus, a special feature of biofilms is that, once they have been developed, they are hard to eradicate, even when careful sanitization procedures are regularly applied. A great deal of ongoing research has investigated how and why surface-attached microbial communities develop such resistance, and several mechanisms are to be acknowledged (e.g., heterogeneous metabolic activity, cell adaptive responses, diffusion limitations, genetic and functional diversification, and microbial interactions). The articles contained in this Special Issue deal with biofilms of some important food-related bacteria (including common pathogens such as Salmonella enterica, Listeria monocytogenes, and Staphylococcus aureus, as well as spoilage-causing spore-forming bacilli), providing novel insights on their resistance mechanisms and implications, together with novel methods (e.g., use of protective biofilms formed by beneficial bacteria, enzymes) that could be used to overcome such resistance and thus improve the safety of our food supply and protect public health.

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