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1.
Eur J Protistol ; 81: 125809, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34673437

RESUMO

Recent studies suggested that the diversity of microbial eukaryotes in hypersaline environments is widely underestimated. Placidids are a group of heterotrophic stramenopile flagellates that are frequently found in these environments, but up to now only very few species were isolated and fully described, mostly from marine or brackish water sites. In this study, we extend the known diversity of Placididea by three new genera (Allegra, Haloplacidia, and Placilonga) compromising nine new species, isolated from athalassic, mostly hypersaline environments (Allegra dunaii, Allegra atacamiensis, Allegra hypersalina, Haloplacidia cosmopolita, Suigetsumonas keniensis) and marine waters (Placilonga atlantica, Placidia azorensis, Placidia abyssalis, Wobblia pacifica) including a description of their morphology and molecular phylogeny. In total, 36 strains were comparatively analysed. Studies from athalassic waters revealed an especially high number of different genotypes. A multigene analysis based on a ten genes dataset revealed a clear separation into marine, athalassic and brackish water clades. Several representatives were found to cope with hypersaline conditions from 20 to 250 PSU, even up to 284 PSU, suggesting that they may form a halotolerant group.


Assuntos
Estramenópilas , Ambientes Extremos , Filogenia , Estramenópilas/genética
2.
BMC Genomics ; 22(1): 635, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465293

RESUMO

BACKGROUND: Brine shrimp Artemia have an unequalled ability to endure extreme salinity and complete anoxia. This study aims to elucidate its strategies to cope with these stressors. RESULTS AND DISCUSSION: Here, we present the genome of an inbred A. franciscana Kellogg, 1906. We identified 21,828 genes of which, under high salinity, 674 genes and under anoxia, 900 genes were differentially expressed (42%, respectively 30% were annotated). Under high salinity, relevant stress genes and pathways included several Heat Shock Protein and Leaf Embryogenesis Abundant genes, as well as the trehalose metabolism. In addition, based on differential gene expression analysis, it can be hypothesized that a high oxidative stress response and endocytosis/exocytosis are potential salt management strategies, in addition to the expression of major facilitator superfamily genes responsible for transmembrane ion transport. Under anoxia, genes involved in mitochondrial function, mTOR signalling and autophagy were differentially expressed. Both high salt and anoxia enhanced degradation of erroneous proteins and protein chaperoning. Compared with other branchiopod genomes, Artemia had 0.03% contracted and 6% expanded orthogroups, in which 14% of the genes were differentially expressed under high salinity or anoxia. One phospholipase D gene family, shown to be important in plant stress response, was uniquely present in both extremophiles Artemia and the tardigrade Hypsibius dujardini, yet not differentially expressed under the described experimental conditions. CONCLUSIONS: A relatively complete genome of Artemia was assembled, annotated and analysed, facilitating research on its extremophile features, and providing a reference sequence for crustacean research.


Assuntos
Artemia , Extremófilos , Animais , Artemia/genética , Ambientes Extremos , Proteínas de Choque Térmico , Salinidade
3.
Extremophiles ; 25(5-6): 425-436, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34542714

RESUMO

Extremophilic prokaryotes live under harsh environmental conditions which require far-reaching cellular adaptations. The acquisition of novel genetic information via natural transformation plays an important role in bacterial adaptation. This mode of DNA transfer permits the transfer of genetic information between microorganisms of distant evolutionary lineages and even between members of different domains. This phenomenon, known as horizontal gene transfer (HGT), significantly contributes to genome plasticity over evolutionary history and is a driving force for the spread of fitness-enhancing functions including virulence genes and antibiotic resistances. In particular, HGT has played an important role for adaptation of bacteria to extreme environments. Here, we present a survey of the natural transformation systems in bacteria that live under extreme conditions: the thermophile Thermus thermophilus and two desiccation-resistant members of the genus Acinetobacter such as Acinetobacter baylyi and Acinetobacter baumannii. The latter is an opportunistic pathogen and has become a world-wide threat in health-care institutions. We highlight conserved and unique features of the DNA transporter in Thermus and Acinetobacter and present tentative models of both systems. The structure and function of both DNA transporter are described and the mechanism of DNA uptake is discussed.


Assuntos
Acinetobacter , Acinetobacter/genética , Ambientes Extremos , Transferência Genética Horizontal , Thermus thermophilus
4.
Extremophiles ; 25(5-6): 437-458, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34586500

RESUMO

One of the main objectives of astrobiological research is the investigation of the habitability of other planetary bodies. Since space exploration missions are expensive and require long-term organization, the preliminary study of terrestrial environments is an essential step to prepare and support exploration missions. The Earth hosts a multitude of extreme environments whose characteristics resemble celestial bodies in our Solar System. In these environments, the physico-chemical properties partly match extraterrestrial environments and could clarify limits and adaptation mechanisms of life, the mineralogical or geochemical context, and support and interpret data sent back from planetary bodies. One of the best terrestrial analogues is Antarctica, whose conditions lie on the edge of habitability. It is characterized by a cold and dry climate (Onofri et al., Nova Hedwigia 68:175-182, 1999), low water availability, strong katabatic winds, salt concentration, desiccation, and high radiation. Thanks to the harsh conditions like those in other celestial bodies, Antarctica offers good terrestrial analogues for celestial body (Mars or icy moons; Léveillé, CR Palevol 8:637-648, https://doi.org/10.1016/j.crpv.2009.03.005 , 2009). The continent could be distinguished into several habitats, each with characteristics similar to those existing on other bodies. Here, we reported a description of each simulated parameter within the habitats, in relation to each of the simulated extraterrestrial environments.


Assuntos
Marte , Planetas , Regiões Antárticas , Exobiologia , Meio Ambiente Extraterreno , Ambientes Extremos
5.
Bioresour Technol ; 337: 125508, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34320776

RESUMO

The photoautotrophic poly(3-hydroxybutyrate) (PHB) production by cyanobacteria is an attractive option as it only requires CO2 and light. In this work, a new wild-type strain producing PHB, Synechococcus elongatus UAM-C/S03, was identified using a polyphasic approach. The strain was cultured in a photobioreactor operated under N-sufficiency conditions at different pH values (7 to 11) and fed with CO2 on demand. We also evaluated the production of PHB under N-starving conditions. Highest biomass productivity, 324 mg L-1 d-1, and CO2 capture, 674 mg L-1 d-1, were obtained at pH 7 and under N-sufficiency conditions. The strain accumulated 29.42% of PHB in dry cell weight (DCW) under N-starvation conditions without pH control, and highest PHB productivity was 58.10 mg L-1 d-1. The highest carbohydrate content registered at pH 8, 50.84% in DCW, along with a release of carbon-based organic compounds, suggested the presence of exopolysaccharides in the culture medium.


Assuntos
Hidroxibutiratos , Synechococcus , Ácido 3-Hidroxibutírico , Ambientes Extremos , Poliésteres
6.
Mar Pollut Bull ; 171: 112707, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34246931

RESUMO

The coral diseases are recognized as serious threats to coral reef ecosystems and a major contributor to the reduction of zooxanthellate scleractinian populations worldwide. Quantitative disease surveys can provide important information on the status and trends of coral reef health over the time. In this study, coral disease surveys were carried out during August 2014 and 2015 at designated sites located in the northern Persian Gulf. Seven different diseases affecting eight scleractinian genera were documented: Black Band Disease (BBD), Skeletal Growth Anomaly (SGA), Arabian Yellow Band Disease (AYBD), White Mat Disease (WMD), White Syndrome (WS), Porites Pink Spot (PPS), and Porites Bleached Patches (PBP). Additionally, it should be noted that this is the first report of SGA in Acropora sp. found in the Persian Gulf. The results of this study generated a baseline dataset of various related diseases in the northern Persian Gulf which can be utilized for future studies.


Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Ambientes Extremos , Oceano Índico
7.
Arch Microbiol ; 203(8): 4961-4972, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34263338

RESUMO

The need for novel and active antibiotics specially from actinomycetes is essential due to new and drug-resistant pathogens. In this study, 87 actinomycetes were isolated, and 18 strains among them characterized as thermophilic actinomycetes. Further fractionation and preliminary antibacterial activities indicated that one strain, coded as MI-S.24-3, showed good antibacterial activity. Based on the phenotypic, genomic, phylogenetic, and biochemical analyses, MI-S.24-3 was identified as Streptomyces werraensis. Results demonstrated that the ethyl acetate active fraction showed maximum antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC (12.7 ± 0.1 and 18.3 ± 0.2 mg/mL), and MBC (96.5 ± 1.4 and 91.5 ± 0.7 mg/mL), respectively, with determination of time kill kinetics assay. The active fraction showed moderate-to-weak cytotoxic effects against human lung carcinoma (A549 cells), breast cancer cell line (MCF-7), and human cervical carcinoma (HELA cells) with a IC50 of (23.8 ± 1.2, 54 ± 1.8, 96.4 ± 3.2 µg/mL, respectively). Active components were characterised by different chemically volatile, ester, and lactone compounds, determined by GC-MS coupled with daughter ions of (GC-MS/MS). Notably, erucic acid and reynosin identified compounds are rare metabolites produced by Streptomyces werraensis. Our findings demonstrated that the MI-S.24-3 strain could be a potential source for active compounds of biomedical and pharmaceutical interest.


Assuntos
Antibacterianos , Espectrometria de Massas em Tandem , Antibacterianos/farmacologia , Egito , Ambientes Extremos , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Streptomyces
8.
Commun Biol ; 4(1): 653, 2021 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-34079059

RESUMO

It has been proposed that adaptation to high temperature involved the synthesis of monolayer-forming ether phospholipids. Recently, a novel membrane architecture was proposed to explain the membrane stability in polyextremophiles unable to synthesize such lipids, in which apolar polyisoprenoids populate the bilayer midplane and modify its physico-chemistry, extending its stability domain. Here, we have studied the effect of the apolar polyisoprenoid squalane on a model membrane analogue using neutron diffraction, SAXS and fluorescence spectroscopy. We show that squalane resides inside the bilayer midplane, extends its stability domain, reduces its permeability to protons but increases that of water, and induces a negative curvature in the membrane, allowing the transition to novel non-lamellar phases. This membrane architecture can be transposed to early membranes and could help explain their emergence and temperature tolerance if life originated near hydrothermal vents. Transposed to the archaeal bilayer, this membrane architecture could explain the tolerance to high temperature in hyperthermophiles which grow at temperatures over 100 °C while having a membrane bilayer. The induction of a negative curvature to the membrane could also facilitate crucial cell functions that require high bending membranes.


Assuntos
Archaea/química , Archaea/fisiologia , Extremófilos/química , Extremófilos/fisiologia , Lipídeos de Membrana/química , Aclimatação/fisiologia , Ambientes Extremos , Temperatura Alta , Bicamadas Lipídicas/química , Fluidez de Membrana , Lipídeos de Membrana/síntese química , Modelos Moleculares , Estrutura Molecular , Difração de Nêutrons , Permeabilidade , Pressão , Espalhamento a Baixo Ângulo , Espectrometria de Fluorescência , Esqualeno/análogos & derivados , Esqualeno/química , Terpenos/química , Difração de Raios X
9.
Sci Rep ; 11(1): 11436, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34075128

RESUMO

The hadal biosphere is one of the least understood ecosystems on our planet. Recent studies have revealed diverse and active communities of prokaryotes in hadal sediment. However, there have been few studies on fungi in hadal sediment. Here we report the first isolation and cultivation of 8 fungi from the Mariana Trench sediment. The individual colonies were isolated and identified as Stemphylium sp., Cladosporium sp., Arthrinium sp., Fusarium sp., Alternaria sp., and Aspergillus sp. High hydrostatic pressure (HHP) test was carried out to identify the piezophily of these hadal fungi. Among them, 7 out of the 8 fungal isolates exhibited the ability of germination after incubation under 40 MPa for 7 days. Vegetative growth of the isolates was also affected by HHP. Characterization of secondary metabolites under different pressure conditions was also performed. The production of secondary metabolites was affected by the HHP treatment, improving the potential of discovering novel natural products from hadal fungi. The antibacterial assay revealed the potential of discovering novel natural products. Our results suggest that fungal growth pressure plays an important role in the development and production of secondary metabolites of these hadal fungi under the extreme environment in the Mariana Trench.


Assuntos
Ambientes Extremos , Fungos , Microbiologia da Água , Organismos Aquáticos/classificação , Organismos Aquáticos/crescimento & desenvolvimento , Organismos Aquáticos/isolamento & purificação , Fungos/classificação , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificação , Pressão Hidrostática , Oceano Pacífico
10.
Appl Ergon ; 95: 103449, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34015663

RESUMO

OBJECTIVES: The aim of this study was to assess current perceptions of heat stress, fatigue and recovery practices during active duty in Australian firefighters. DESIGN: Prospective survey. METHODS: 473 firefighters from Fire and Rescue New South Wales completed a two-part, 16-item survey. Questions included perceptions of the operational activities and body areas associated with the most heat stress, the most mentally and physically demanding activities, and levels of fatigue felt. Further questions focussed on the use and importance of recovery practices, effectiveness of currently used heat-mitigation strategies and additional cooling strategies for future use. RESULTS: Around a third of firefighters (62%) reported structural fire-fighting as the hottest operational activities experienced, followed by bushfire-fighting (51%) and rescue operations (38%). The top three responses for which body-parts get the hottest ranked as 'the head' (58%), 'the whole body' (54%) and 'the upper back' (40%), respectively. The majority of firefighters (~90%) stated they always or sometimes use the opportunity to recover at an incident, with the top three being 'sit in the shade' (93%), 'cold water ingestion (drinking)' (90%) and 'removing your helmet, flash hood and jacket' (89%). Firefighters reported higher usefulness for more easily deployed strategies compared to more advanced strategies. Limited age and gender differences were found, although location of active service differences were present. CONCLUSION: These findings may inform future research, and translation to operational directives for recovery interventions; including exploration of protective gear and clothing, education, resources and provision of cooling methods, as well as recovery aid development.


Assuntos
Bombeiros , Austrália , Ambientes Extremos , Fadiga , Resposta ao Choque Térmico , Humanos , Percepção , Estudos Prospectivos
11.
PLoS Genet ; 17(5): e1009530, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33983934

RESUMO

Hadal environments (depths below 6,000 m) are characterized by extremely high hydrostatic pressures, low temperatures, a scarce food supply, and little light. The evolutionary adaptations that allow vertebrates to survive in this extreme environment are poorly understood. Here, we constructed a high-quality reference genome for Yap hadal snailfish (YHS), which was captured at a depth of ~7,000 m in the Yap Trench. The final YHS genome assembly was 731.75 Mb, with a contig N50 of 0.75 Mb and a scaffold N50 of 1.26 Mb. We predicted 24,329 protein-coding genes in the YHS genome, and 24,265 of these genes were successfully functionally annotated. Phylogenetic analyses suggested that YHS diverged from a Mariana Trench snailfish approximately 0.92 million years ago. Many genes associated with DNA repair show evidence of positive selection and have expanded copy numbers in the YHS genome, possibly helping to maintain the integrity of DNA under increased hydrostatic pressure. The levels of trimethylamine N-oxide (TMAO), a potent protein stabilizer, are much higher in the muscles of YHS than in those of shallow-water fish. This difference is perhaps due to the five copies of the TMAO-generating enzyme flavin-containing monooxygenase-3 gene (fmo3) in the YHS genome and the abundance of trimethylamine (TMA)-generating bacteria in the YHS gut. Thus, the high TMAO content might help YHS adapt to high hydrostatic pressure by improving protein stability. Additionally, the evolutionary features of the YHS genes encoding sensory-related proteins are consistent with the scarce food supply and darkness in the hadal environments. These results clarify the molecular mechanisms underlying the adaptation of hadal organisms to the deep-sea environment and provide valuable genomic resources for in-depth investigations of hadal biology.


Assuntos
Aclimatação/genética , Ambientes Extremos , Peixes/genética , Genoma/genética , Oceanos e Mares , Sequenciamento Completo do Genoma , Animais , Reparo do DNA/genética , Escuridão , Evolução Molecular , Peixes/classificação , Pressão Hidrostática , Metilaminas/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Filogenia , Estabilidade Proteica
12.
Sci Rep ; 11(1): 10963, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34040064

RESUMO

The mutational robustness of the genetic code is rarely discussed in the context of biological diversity, such as codon usage and related factors, often considered as independent of the actual organism's proteome. Here we put the living beings back to picture and use distortion as a metric of mutational robustness. Distortion estimates the expected severities of non-synonymous mutations measuring it by amino acid physicochemical properties and weighting for codon usage. Using the biological variance of codon frequencies, we interpret the mutational robustness of the standard genetic code with regards to their corresponding environments and genomic compositions (GC-content). Employing phylogenetic analyses, we show that coding fidelity in physicochemical properties can deteriorate with codon usages adapted to extreme environments and these putative effects are not the artefacts of phylogenetic bias. High temperature environments select for codon usages with decreased mutational robustness of hydrophobic, volumetric, and isoelectric properties. Selection at high saline concentrations also leads to reduced fidelity in polar and isoelectric patterns. These show that the genetic code performs best with mesophilic codon usages, strengthening the view that LUCA or its ancestors preferred lower temperature environments. Taxonomic implications, such as rooting the tree of life, are also discussed.


Assuntos
Uso do Códon , Evolução Molecular , Ambientes Extremos , Código Genético , Mutação , Origem da Vida , Substituição de Aminoácidos , Teorema de Bayes , Códon , Variação Genética , Temperatura Alta , Análise dos Mínimos Quadrados , Modelos Genéticos , Filogenia , Biossíntese de Proteínas , Salinidade , Seleção Genética
13.
Neurosci Biobehav Rev ; 126: 413-429, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33836214

RESUMO

PALINKAS, L.A., and P. SUEDFELD. Psychosocial Issues in Isolated and Confined Extreme Environments. NEUROSCI BIOBEHAV REV (1) XXX-XXX, 2020. Psychosocial elements of behavior and performance will significantly impact the outcomes of long duration missions in space, ranging from individual and team decrements to positive benefits associated with successful adaptation. This paper reviews our current understanding of the individual, interpersonal and organizational issues related to living and working in isolated and confined extreme (ICE) environments. Individual issues include changes in emotions and cognitive performance; seasonal syndromes linked to changes in the physical environment; and positive effects of adapting to ICE environments. Interpersonal issues include processes of crew cohesion, tension and conflict; interpersonal relations and social support; the impact of group diversity and leadership styles on small group dynamics; and crew-mission control interactions. Organizational issues include the influence of organizational culture and mission duration on individual and group performance, crew autonomy, and managerial requirements for long duration missions. Improved screening and selection, leadership, coping and interpersonal skills training, and organizational change are key elements to optimizing adjustment to the environment and preventing decrements during and after long duration missions.


Assuntos
Processos Grupais , Voo Espacial , Adaptação Psicológica , Astronautas , Ambientes Extremos , Humanos , Relações Interpessoais , Isolamento Social
14.
ISME J ; 15(10): 2892-2905, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33903726

RESUMO

Membrane-bound extracellular vesicles (EVs), secreted by cells from all three domains of life, transport various molecules and act as agents of intercellular communication in diverse environments. Here we demonstrate that EVs produced by a hyperthermophilic and acidophilic archaeon Sulfolobus islandicus carry not only a diverse proteome, enriched in membrane proteins, but also chromosomal and plasmid DNA, and can transfer this DNA to recipient cells. Furthermore, we show that EVs can support the heterotrophic growth of Sulfolobus in minimal medium, implicating EVs in carbon and nitrogen fluxes in extreme environments. Finally, our results indicate that, similar to eukaryotes, production of EVs in S. islandicus depends on the archaeal ESCRT machinery. We find that all components of the ESCRT apparatus are encapsidated into EVs. Using synchronized S. islandicus cultures, we show that EV production is linked to cell division and appears to be triggered by increased expression of ESCRT proteins during this cell cycle phase. Using a CRISPR-based knockdown system, we show that archaeal ESCRT-III and AAA+ ATPase Vps4 are required for EV production, whereas archaea-specific component CdvA appears to be dispensable. In particular, the active EV production appears to coincide with the expression patterns of ESCRT-III-1 and ESCRT-III-2, rather than ESCRT-III, suggesting a prime role of these proteins in EV budding. Collectively, our results suggest that ESCRT-mediated EV biogenesis has deep evolutionary roots, likely predating the divergence of eukaryotes and archaea, and that EVs play an important role in horizontal gene transfer and nutrient cycling in extreme environments.


Assuntos
Archaea , Vesículas Extracelulares , Archaea/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Ambientes Extremos , Nutrientes
15.
BMC Microbiol ; 21(1): 119, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33874905

RESUMO

BACKGROUND: Salinization damages the health of soil systems and reduces crop yields. Responses of microbial communities to salinized soils and their functional maintenance under high salt stress are valuable scientific problems. Meanwhile, the microbial community of the salinized soil in the plateau environment is less understood. Here, we applied metagenomics technology to reveal the structure and function of microorganisms in salinized soil of the Tibetan Plateau. RESULTS: The diversity of composition and function of microbial community in saline soil have changed significantly. The abundances of chemoautotrophic and acidophilic bacteria comprising Rhodanobacter, Acidobacterium, Candidatus Nitrosotalea, and Candidatus Koribacter were significantly higher in saline soil. The potential degradation of organic carbon in the saline soil, as well as the production of NO and N2O via denitrification, and the production of sulfate by sulfur oxidation were significantly higher than the non-saline soil. Both types of soils were rich in genes encoding resistance to environmental stresses (i.e., cold, ultraviolet light, and hypoxia in Tibetan Plateau). The resistance of the soil microbial communities to the saline environment is based on the absorption of K+ as the main mechanism, with cross-protection proteins and absorption buffer molecules as auxiliary mechanisms in our study area. Network analysis showed that functional group comprising chemoautotrophic and acidophilic bacteria had significant positive correlations with electrical conductivity and total sulfur, and significant negative correlations with the total organic carbon, pH, and available nitrogen. The soil moisture, pH, and electrical conductivity are likely to affect the bacterial carbon, nitrogen, and sulfur cycles. CONCLUSIONS: These results indicate that the specific environment of the Tibetan Plateau and salinization jointly shape the structure and function of the soil bacterial community, and that the bacterial communities respond to complex and harsh living conditions. In addition, environmental feedback probably exacerbates greenhouse gas emissions and accelerates the reduction in the soil pH. This study will provide insights into the microbial responses to soil salinization and the potential ecological risks in the special plateau environment.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biodiversidade , Ambientes Extremos , Microbiota/genética , Microbiologia do Solo , Solo/química , Estresse Fisiológico/fisiologia , Bactérias/genética , Fazendas , Metagenômica , Tolerância ao Sal , Tibet
16.
Arch Microbiol ; 203(5): 2521-2540, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33677634

RESUMO

The acid ponds of the Danakil Depression in northern Ethiopia are polyextreme environments that exceed the normal physicochemical limits of pH, salinity, ion content, and temperature. We tested for the occurrence of DNA-based life in this environment using Metagenomic Shotgun DNA sequencing approaches. The obtained sequences were examined by the bioinformatic tools MetaSpades, DIAMOND and MEGAN 6-CE, and we were able to bin more than 90% of the metagenomics contigs of Dallol and Black Water to the Bacteria domain, and to the Proteobacteria phylum. Predictions of gene function based on SEED disclosed the presence of different nutrient cycles in the acid ponds. For this study, we focused on partial or completely sequenced genes involved in nitrogen metabolism. The KEGG nitrogen metabolism pathway mapping results for both acid ponds showed that all the predicted genes are involved directly or indirectly in the assimilation of ammonia and no dissimilation or nitrification process was identified. Furthermore, the deduced nitrogen fixation in the two acid ponds based on SEED classification indicated the presence of different sets of nitrogen fixing (nif) genes for biosynthesis and maturation of nitrogenase. Based on the in silico analysis, the predicted proteins involved in nitrogen fixation, especially the cysteine desulfurase and [4Fe-4S] ferredoxin, from both acid ponds are unique with less than 80% sequence similarity to the next closest protein sequence. Considering the extremity of the environmental conditions of the two acid ponds in the Danakil depression, this metagenomics dataset can add to the study of unique gene functions in nitrogen metabolism that enable thriving biocommunities in hypersaline and highly acidic conditions.


Assuntos
Bactérias/metabolismo , Ambientes Extremos , Nitrogênio/metabolismo , Amônia/metabolismo , Bactérias/genética , Proteínas de Bactérias/genética , Simulação por Computador , Metagenômica , Fixação de Nitrogênio/genética , Nitrogenase/genética , Lagoas/química , Lagoas/microbiologia
17.
Sensors (Basel) ; 21(4)2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33670324

RESUMO

Antarctica is a space-analog ICE (isolated, cold, and extreme) environment. Cardiovascular and heart autonomic adjustments are key-adaptive physiological responses to Antarctica, both in summer camps and in research stations winter-over. Research fieldwork in ICE environments imposes limitations such as energy restriction, the need for portable and easy-to-handle resources, and resistance of materials to cold and snow/water. Herein, we present the methods we use for cardiac monitoring in the Antarctic field, the limitations of the equipment currently available, and the specific demands for smart wearables to physiological and health tracking in ICE environments, including the increased remote monitoring demand due to COVID-19 restrictions.


Assuntos
Ambientes Extremos , Dispositivos Eletrônicos Vestíveis , Regiões Antárticas , Humanos
18.
G3 (Bethesda) ; 11(1)2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33561229

RESUMO

The gray mangrove [Avicennia marina (Forsk.) Vierh.] is the most widely distributed mangrove species, ranging throughout the Indo-West Pacific. It presents remarkable levels of geographic variation both in phenotypic traits and habitat, often occupying extreme environments at the edges of its distribution. However, subspecific evolutionary relationships and adaptive mechanisms remain understudied, especially across populations of the West Indian Ocean. High-quality genomic resources accounting for such variability are also sparse. Here we report the first chromosome-level assembly of the genome of A. marina. We used a previously release draft assembly and proximity ligation libraries Chicago and Dovetail HiC for scaffolding, producing a 456,526,188-bp long genome. The largest 32 scaffolds (22.4-10.5 Mb) accounted for 98% of the genome assembly, with the remaining 2% distributed among much shorter 3,759 scaffolds (62.4-1 kb). We annotated 45,032 protein-coding genes using tissue-specific RNA-seq data in combination with de novo gene prediction, from which 34,442 were associated to GO terms. Genome assembly and annotated set of genes yield a 96.7% and 95.1% completeness score, respectively, when compared with the eudicots BUSCO dataset. Furthermore, an FST survey based on resequencing data successfully identified a set of candidate genes potentially involved in local adaptation and revealed patterns of adaptive variability correlating with a temperature gradient in Arabian mangrove populations. Our A. marina genomic assembly provides a highly valuable resource for genome evolution analysis, as well as for identifying functional genes involved in adaptive processes and speciation.


Assuntos
Avicennia , Genoma de Planta , Avicennia/genética , Ambientes Extremos , Genômica , Anotação de Sequência Molecular , Fenótipo
19.
Annu Rev Biophys ; 50: 343-372, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33637008

RESUMO

Sampling and genomic efforts over the past decade have revealed an enormous quantity and diversity of life in Earth's extreme environments. This new knowledge of life on Earth poses the challenge of understandingits molecular basis in such inhospitable conditions, given that such conditions lead to loss of structure and of function in biomolecules from mesophiles. In this review, we discuss the physicochemical properties of extreme environments. We present the state of recent progress in extreme environmental genomics. We then present an overview of our current understanding of the biomolecular adaptation to extreme conditions. As our current and future understanding of biomolecular structure-function relationships in extremophiles requires methodologies adapted to extremes of pressure, temperature, and chemical composition, advances in instrumentation for probing biophysical properties under extreme conditions are presented. Finally, we briefly discuss possible future directions in extreme biophysics.


Assuntos
Ambientes Extremos , Animais , Biofísica , Extremófilos , Humanos , Temperatura
20.
Microbiome ; 9(1): 50, 2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33602336

RESUMO

BACKGROUND: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth's ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. METHODS: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. RESULTS: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. CONCLUSIONS: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders. Video abstract.


Assuntos
Exobiologia , Ambientes Extremos , Microbiota/fisiologia , Anaerobiose , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Metagenoma , Microbiota/genética
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