Search

This article is an editorial published in Frontiers in Microbiology titled "Acidophile microbiology: from extreme environments to biotechnological applications." The editorial discusses the wide range of environments in which acidophiles are found and their adaptions to extreme conditions. It highlights the potential of acidophilic microorganisms for industrial applications, particularly in biomining. The article also covers research on acidophiles in bioleaching, mineral dissolution, biofilm formation, bioremediation, and the unique enzymes and proteins derived from acidophiles. Additionally, it emphasizes the contribution of acidophile microbiology to our understanding of microbial diversity and adaptation strategies in extreme environments. The article concludes by stating that acidophile microbiology fosters biological innovation and biotechnological advancement. [Extracted from the article]

Biological experiments performed in space crafts like space stations, space shuttles, and recoverable satellites has enabled extensive spaceflight life investigations (SLIs). In particular, SLIs have revealed distinguished space effects on microbial growth, survival, metabolite production, biofilm formation, virulence development and drug resistant mutations. These provide unique perspectives to ground-based microbiology and new opportunities for industrial pharmaceutical and metabolite productions. SLIs are with specialized experimental setups, analysis methods and research outcomes, which can be accessed by established databases National Aeronautics and Space Administration (NASA) Life Science Data Archive, Erasmus Experiment Archive, and NASA GeneLab. The increasing research across diverse fields may be better facilitated by databases of convenient search facilities and categorized presentation of comprehensive contents. We therefore developed the Space Life Investigation Database (SpaceLID) http://bidd.group/spacelid/, which collected SLIs from published academic papers. Currently, this database provides detailed menu search facilities and categorized contents about the studied phenomena, materials, experimental procedures, analysis methods, and research outcomes of 448 SLIs of 90 species (microbial, plant, animal, human), 81 foods and 106 pharmaceuticals, including 232 SLIs not covered by the established databases. The potential applications of SpaceLID are illustrated by the examples of published experimental design and bioinformatic analysis of spaceflight microbial phenomena. [ABSTRACT FROM AUTHOR]

Extreme environments such as soda lakes are potential sources of microbes with biotechnological applications in different sectors. This study aimed at isolation, characterization and investigation of antibacterial potential of actinobacteria from Momela Soda Lakes, at Arusha National Park in Tanzania. One hundred and twenty (120) isolates were recovered from soil and water samples using the dilution plate technique. The isolates were morphologically and biochemically characterized, and further, screened for antimicrobial activity by disc diffusion method as well as the micro dilution technique. Cytotoxic effects were determined using the brine shrimp lethality test. Results showed that, all 120 isolates were Gram-positive rod-coccus shaped. Forty-four out of them showed antibacterial activity against Staphylococcus aureus and Escherichia coli. The Streptomyces (101TI) and Dietzia (56BI) strains exhibited exceptionally higher antibacterial activity compared to the rest with inhibition zones of 16.25 and 21.00 mm, respectively. These two strains were toxic against brine shrimplarvae. Microbacterium (5LI), Hoyosella (113BI), Streptomyces (62BI), Dietzia (117SI), Hoyosella (37SI) and Microbacterium (3BI) strains had low antibacterial and cytotoxic activities. This study therefore revealed that Momela Soda Lakes harbour actinobacteria with antimicrobial potential. [ABSTRACT FROM AUTHOR]

Proteases are the most economical enzymes in biotechnology and industry. Nowadays, a lot of attention is being paid to extremophiles microorganisms owing to the diversity of their enzymes. One hundred and Six proteolytic bacteria were isolated from Binaloud Mountain; one of them (strain BTR88) was selected as the best producer of extracellular protease and was used for further studies. This bacterium belongs to Stenotrophomonas sp., which were identified by the 16S rDNA sequence. Maximal protease production was detected at the beginning of exponential growth phase in the presence of starch and skim milk at 20°C and pH 9. This protease was purified to electrophoretic homogeneity with a fold: 27.5, yield: 33% and specific enzyme: 12.6 U/mg. SDS-PAGE and zymography analyses revealed a protein band of 22 kDa. The maximum activity was at pH 9 and in the range of 20-30°C; while, the enzyme exhibited a broad range of activity from 20-80°C as well as the pH of 5-10. Enzyme inhibition in the presence of phenylmethane sulfonyl fluoride (PMSF) and Ethylenediaminetetraacetic acid (EDTA) showed that the purified enzyme belongs to serine metallo-enzymes. Kinetic parameters of km, Vmax and kcat for the cold tolerant enzyme were determined to be 7.2 mg/mL, 1.45 mM/min and 33.2 sec-1, respectively. The characteristics of activity in cold and alkaline conditions and the broad range of pH and temperature suggest that serine metalloprotease has potential use in the detergent industry. [ABSTRACT FROM AUTHOR]

We study four citrate synthase homodimeric proteins within a structure-based coarse-grained model. Two of these proteins come from thermophilic bacteria, one from a cryophilic bacterium and one from a mesophilic organism; three are in the closed and two in the open conformations. Even though the proteins belong to the same fold, the model distinguishes the properties of these proteins in a way which is consistent with experiments. For instance, the thermophilic proteins are more stable thermodynamically than their mesophilic and cryophilic homologues, which we observe both in the magnitude of thermal fluctuations near the native state and in the kinetics of thermal unfolding. The level of stability correlates with the average coordination number for amino acid contacts and with the degree of structural compactness. The pattern of positional fluctuations along the sequence in the closed conformation is different than in the open conformation, including within the active site. The modes of correlated and anticorrelated movements of pairs of amino acids forming the active site are very different in the open and closed conformations. Taken together, our results show that the precise location of amino acid contacts in the native structure appears to be a critical element in explaining the similarities and differences in the thermodynamic properties, local flexibility, and collective motions of the different forms of the enzyme. [ABSTRACT FROM AUTHOR]

In the harshest environmental conditions of the Antarctic desert, normally incompatible with active life, microbes are adapted to exploit the cryptoendolithic habitat (i.e., pore spaces of rocks) and represent the predominant life-forms. In the rocky niche, microbes take advantage of the thermal buffering, physical stability, protection against UV radiation, excessive solar radiation, and water retention—of paramount importance in one of the driest environments on Earth. In this work, high-throughput sequencing and culture-dependent approaches have been combined, for the first time, to untangle the diversity and distribution of black fungi in the Antarctic cryptoendolithic microbial communities, hosting some of the most extreme-tolerant microorganisms. Rock samples were collected in a vast area, along an altitudinal gradient and opposite sun exposure—known to influence microbial diversity—with the aim to compare and integrate results gained with the two approaches. Among black fungi, Friedmanniomyces endolithicus was confirmed as the most abundant taxon. Despite the much stronger power of the high-throughput sequencing, several species were not retrieved with DNA sequencing and were detectable by cultivation only. We conclude that both culture-dependent and -independent analyses are needed for a complete overview of black fungi diversity. The reason why some species remain undetectable with molecular methods are speculated upon. The effect of environmental parameters such as sun exposure on relative abundance was clearer if based on the wider biodiversity detected with the molecular approach. [ABSTRACT FROM AUTHOR]

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. 4ky3Zi4SfdfTiNhAX3nKcy Video abstract [ABSTRACT FROM AUTHOR]

The Cyanidiophyceae are a class of unicellular red algae that live in environments at the extremes of temperature, pH, salt, and heavy metal concentrations. These photosynthetic organisms have been able to occupy these rather unusual niches by acquiring a variety of genes from extremophilic prokaryotes and/or viruses via the process of horizontal gene transfer (HGT). Elucidating how the proteins encoded by these genes integrate into existing metabolic systems is crucial to understanding and evaluating the significance of HGT in eukaryotes and its role in conferring adaptive traits. This article addresses the fundamentals of HGT in model red algae, its function as a driver of evolution across the web of life with a focus on eukaryotes, and summarizes ongoing work and the future directions of this field. [ABSTRACT FROM AUTHOR]

Summary: The prevalence of multidrug‐resistant microbial pathogens due to the continued misuse and overuse of antibiotics in agriculture and medicine is raising the prospect of a return to the preantibiotic days of medicine at the time of diminishing numbers of drug leads. The good news is that an increased understanding of the nature and extent of microbial diversity in natural habitats coupled with the application of new technologies in microbiology and chemistry is opening up new strategies in the search for new specialized products with therapeutic properties. This review explores the premise that harsh environmental conditions in extreme biomes, notably in deserts, permafrost soils and deep‐sea sediments select for micro‐organisms, especially actinobacteria, cyanobacteria and fungi, with the potential to synthesize new druggable molecules. There is evidence over the past decade that micro‐organisms adapted to life in extreme habitats are a rich source of new specialized metabolites. Extreme habitats by their very nature tend to be fragile hence there is a need to conserve those known to be hot‐spots of novel gifted micro‐organisms needed to drive drug discovery campaigns and innovative biotechnology. This review also provides an overview of microbial‐derived molecules and their biological activities focusing on the period from 2010 until 2018, over this time 186 novel structures were isolated from 129 representatives of microbial taxa recovered from extreme habitats. [ABSTRACT FROM AUTHOR]

Halophilic proteins subjected to below about 15% salt in vitro denature through misfolding, aggregation and/or precipitation. Halobacteria, however, have been detected in environments of fluctuating salinity such as coastal salterns and even around fresh water springs in the depths of the Dead Sea. In order to identify the underlying mechanisms of low salt survival, we explored the reactivation capacity of Halobacterium (Hbt) salinarum sub-populations after incubation in low salt media and recovery in physiological salt. Respiratory oxygen consumption was assessed in stressed cells and cell viability was estimated by Live/Dead staining and flow cytometry. In vivo neutron scattering experiments showed that the recovery of Hbt salinarum sub-populations exposed to severe low salt conditions is related to a rapid retrieval of functional molecular dynamics in the proteome. In the hypothesis that the observations on Hbt salinarum have wider relevance, they could be of key ecological significance for the dispersion of extremophiles when environmental fluctuations become severe. [ABSTRACT FROM AUTHOR]

Marine environment contains organisms that make it a profitable natural reservoir, having a tremendous potential to produce functional bio-catalysis, such as amylase, lipase, protease, curtains etc. The enzymes isolated from marine organisms, especially extremophiles, are distinguished by their habitat-related features through bioprospecting processes. These novel features include barophilicity, cold adaptively, salt tolerance and hyperthermo-stability which can alter industrial processes to facilitate mass transfer, energy savings, cost reduction, etc. This review gives details about the marine enzymes and their, historical discovery followed by isolation processes, introducing seven special marine enzymes with emphasis on their potential applications in chemical, food and pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Trinidadian guppies (Poecilia reticulata) are able to adapt to various environmental conditions and are even among the few species that can tolerate extensive pollution. In the Pitch Lake of Trinidad they live in highly toxic waters due to natural seepage of oil and bitumen. In this paper, we describe phenotypic divergence in several life-history traits between guppies from the Pitch Lake and from a nearby reference site with waters not polluted by bitumen/oil. We show that guppies from the Pitch Lake were (i) smaller and (ii) had a higher reproductive investment than those from the reference site. Furthermore, they (iii) produced more and smaller offspring. These results are congruent with a scenario of high mortality caused probably by a combination of water toxicity and higher predation than at the reference site. We therefore propose the Pitch Lake as an ideal system to study the effects of long-term (natural) water pollution on fishes, which might provide interesting insights into adaptation to extreme environments, and might further help to predict fish responses to anthropogenic pollution. [ABSTRACT FROM AUTHOR]

Background: Dissolution of chalcopyrite is one of the most important challenges in hydrometallurgy because it is very difficult to leach due to the passivation of its surface, whose nature is still controversial. The addition of chloride ions can catalyse copper dissolution, but when it comes to bioleaching, chloride usually cannot be applied because of its toxicity to most bioleaching bacteria. Results: The current work investigated, for the first time, chalcopyrite bioleaching with Sulfolobus acidocaldarius at high concentrations of chloride [up to 1.0 mol L−1 sodium chloride (NaCl)] and 67.5 °C. Copper dissolution attained 100% within 14 days in the presence of microorganisms, while only 55% was observed in the abiotic test; both tests were carried out with 1.0 mol L−1 NaCl. Raman spectroscopy of the leached chalcopyrite with S. acidocaldarius and 1.0 mol L−1 NaCl revealed the presence of elemental sulphur as a reaction product on the fifth day of the experiment; jarosite was also detected after 14 days in the same test. Conclusion: Because of the low ability of the archaea to oxidize ferrous ion, the redox potential of the biotic test, having 1.0 mol L−1 of chloride, remained most of the time in the range 350–420 mV, in which the leaching rate of chalcopyrite was the highest. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Although arsenic (As) is recognized as a toxic element for living species, some microorganisms have the ability to tolerate and transform it; recent studies have proposed to take advantage of such capacity to develop sustainable bioremediation strategies. In this study, we evaluated the adaptation to increasing concentrations of As(III) and As(V) of three metabolically different microbial cultures (heterotrophic, autotrophic–acidophilic, and anaerobic) obtained from a sample with low‐soluble As content from the Copahue geothermal system. At the end of the adaptation process, the heterotrophic culture was able to grow at 20 mM and 450 mM of As(III) and As(V), respectively; the autotrophic–acidophilic culture showed tolerance to 15 mM of As(III) and 150 mM of As(V), whereas the anaerobic culture only developed in As(V) at concentrations up to 50 mM. The most tolerant consortia were characterized by their growth performance, complexity, and the presence of genes related to As metabolism and resistance. Regarding the consortia complexity, the predominant genera identified were: Paenibacillus in both heterotrophic consortia, Acidithiobacillus in the autotrophic–acidophilic consortium tolerant to As(III), Acidiphilium in the autotrophic–acidophilic consortium tolerant to As(V), and Thiomonas and Clostridium in the anaerobic consortium. This study is the first report of As tolerance microorganisms obtained from Copahue and reasserts the versatility and flexibility of the community of this natural extreme environment; also, it opens the door to the study of possible uses of these consortia in the design of biotechnological processes where the As concentration may fluctuate. [ABSTRACT FROM AUTHOR]

Orestias ascotanensis Parenti is a critically-endangered fish species endemic to the Ascotán salt pan springs. Given the importance of reproduction and early development in effective conservation of fish populations, this study describes the embryonic development of O. ascotanensis under laboratory conditions. Between 2014 and 2015, 50 individuals were captured and maintained under controlled conditions, including temperature, photoperiod and feeding regimen, to induce spawning for artificial fertilization. Females were subjected to hormone therapy with Ovaprim®. Water temperature was maintained at 20 °C (± 1 °C), conductivity at 2800–3600 μS·cm−1 and photoperiod at 16:8 (light hours: dark hours). Males showed changes in color and courtship behavior, and females developed a slightly bulging belly. Eggs were 1.55–2.5 mm in diameter, with abundant yolk and dozens of adhesion filaments. Embryonic development lasted 14–18 days; it was divided into five periods, which can be sub-divided into 21 stages, from fertilization to hatching. O. ascotanensis showed indications of partial spawning species, including oocytes at different stages of development, relatively large eggs as compared to adult fish length and low batch spawning. Characteristics such as partial spawning, highly-pigmented eggs and larvae and advanced larval development at hatching could be adaptations to the extreme conditions of the salt pan springs, including high levels of ultraviolet radiation and salinity as well as significant daily temperature changes. [ABSTRACT FROM AUTHOR]

Abstract Quorum sensing plays important roles in the regulation of physiological and virulence processes in most bacteria, but its role in extremophiles is largely unknown. Comparative genomic, phylogenic, structural and signaling pathways analyses and deletion mutant studies have suggested the presence of three major quorum sensing systems (AI-1, Peptide based and AI-2) in extremophiles. Autoinducer-1(AI-1) system was found to be most prevalent (except in thermophiles where it is autoinducer-2) while peptide based system was least prevalent in extremophiles. Some unknown mechanisms of quorum sensing have also been reported which need further exploration. Quorum sensing is utilized by extremophiles for processes like cold adaptation, lowering the freezing point, biofilm formation, oxidative stress resistance and persister cell formation. Explication of quorum sensing in extreme environments may provide discernment regarding the role and functional strategies for survival of extremophiles. Here the role of quorum sensing in different classes of extremophiles and also in their survival strategies has been reviewed. Further, the applications and problems caused by quorum sensing regulated factors in extreme environments are discussed. [ABSTRACT FROM AUTHOR]

The effects of nitrogen concentration and pH on the growth kinetics of the extremophile microalgal strain Coccomyxa melkonianii SCCA 048 in multiwell and batch photobioreactors are investigated in this work. Moreover, the experimental results were successfully interpreted by a simple, mathematical model which represents a starting point towards the development of a suitable tool for the design, control, and optimization of large scale photobioreactors where C. melkonianii would be cultivated. On the basis of fatty acids methyl esters (FAMEs) profile, potential properties of biodiesel have been predicted through suitable software. [ABSTRACT FROM AUTHOR]

Abstract There are few environments more hostile and species-poor than deserts and the mounds of Nasutitermitinae termites. However, despite the very different adaptations required to survive in such extreme and different environments, the fungal genus Podaxis is capable of surviving in both: where few other fungi are reported to grow. Despite their prominence in the landscape and their frequent documentation by early explorers, there has been relatively little research into the genus. Originally described by Linnaeus in 1771, in the early 20th Century, the then ∼25 species of Podaxis were almost entirely reduced into one species: Podaxis pistillaris. Since this reduction, several new species of Podaxis have been described but without consideration of older descriptions. This has resulted in 44 recognised species names in Index Fungorum but the vast majority of studies and fungarium specimens still refer to P. pistillaris. Studies of Podaxis ' extremely different lifestyles is hampered by its effective reduction to a single-species genus. Here we examine the history of the taxonomy of Podaxis before focusing on its extreme lifestyles. From this, we consider how the muddled taxonomy of Podaxis may be resolved; opening up further avenues for future research into this enigmatic fungal genus. Highlights • Podaxis survives in both hot deserts and the interior of termite mounds. • Many herbarium specimens apparently mislabeled as a single species. • Podaxis possesses adaptations to desert life and grows at high temperatures. • Podaxis produces a broad range of secondary compounds. • The genus has great potential for further study. [ABSTRACT FROM AUTHOR]

Poly-extreme terrestrial habitats are often used as analogs to extra-terrestrial environments. Understanding the adaptive strategies allowing bacteria to thrive and survive under these conditions could help in our quest for extra-terrestrial planets suitable for life and understanding how life evolved in the harsh early earth conditions. A prime example of such a survival strategy is the modification of vegetative cells into resistant resting structures. These differentiated cells are often observed in response to harsh environmental conditions. The environmental strain (strain Lr5/4) belonging to Serratia ureilytica was isolated from a geothermal spring in Lirima, Atacama Desert, Chile. The Atacama Desert is the driest habitat on Earth and furthermore, due to its high altitude, it is exposed to an increased amount of UV radiation. The geothermal spring from which the strain was isolated is oligotrophic and the temperature of 54°C exceeds mesophilic conditions (15 to 45°C). Although the vegetative cells were tolerant to various environmental insults (desiccation, extreme pH, glycerol), a modified cell type was formed in response to nutrient deprivation, UV radiation and thermal shock. Scanning (SEM) and Transmission Electron Microscopy (TEM) analyses of vegetative cells and the modified cell structures were performed. In SEM, a change toward a circular shape with reduced size was observed. These circular cells possessed what appears as extra coating layers under TEM. The resistance of the modified cells was also investigated, they were resistant to wet heat, UV radiation and desiccation, while vegetative cells did not withstand any of those conditions. A phylogenomic analysis was undertaken to investigate the presence of known genes involved in dormancy in other bacterial clades. Genes related to spore-formation in Myxococcus and Firmicutes were found in S. ureilytica Lr5/4 genome; however, these genes were not enough for a full sporulation pathway that resembles either group. Although, the molecular pathway of cell differentiation in S. ureilytica Lr5/4 is not fully defined, the identified genes may contribute to the modified phenotype in the Serratia genus. Here, we show that a modified cell structure can occur as a response to extremity in a species that was previously not known to deploy this strategy. This strategy may be widely spread in bacteria, but only expressed under poly-extreme environmental conditions. [ABSTRACT FROM AUTHOR]

Abstract The knowledge of the astonishing diversity of intracellular, photosynthetic dinoflagellates in the family Symbiodiniaceae, which have crucial symbioses with scleractinian corals, is essential to anticipate the adaptive response of corals to environmental stressors. Coral reefs in the northern Persian Gulf (nPG) and Gulf of Oman (nGO) experience a wide range of natural (e.g., high and low water temperature, high salinity) and anthropogenic (e.g., different levels of turbidity) disturbances, and so are excellent models to study the effects of these conditions on the biogeography of symbiotic alga. In this regard, the algal component of an acroporid coral was genotyped using chloroplastic 23S, nuclear 28S and the internal transcribed spacer 2 of ribosomal DNA across the nPG and nGO. Two genera (three distinct taxa) were detected, all of which corresponded to previously reported phylogenetic lineages. Durusdinium trenchii was found to be widely distributed in nearly all examined locations in the nPG and nGO. The turbid waters of the nGO and the harsh conditions in the eastern nPG may to some extent explain the ecological success of D. trenchii in these areas. However, in the westernmost nPG (Kharkoo Island), Acropora sp. solely harbored Cladocopium thermophilum. The occurrence of this thermotolerant species only at the westernmost nPG (with higher salinity and water clarity) may reveal the potency of low salinity and excessive turbidity as distribution barriers for the association of these symbiont lineages and corals (at least acroporids) outside the Persian Gulf. Highlights • Acroporids enduring extreme conditions harbor tolerant lineages of Symbiodiniaceae. • Cladocopium thermophilum was found in the northwestern Persian Gulf. • Rest of the northern Persian Gulf and Gulf of Oman were dominated by Durusdinium trenchii. • Salinity and turbidity may act as distribution barriers for C. thermophilum. • Acropora corals were host to C. thermophilum in the northwestern Persian Gulf. [ABSTRACT FROM AUTHOR]

Abstract Numerous microorganisms inhabiting harsh niches produce exopolysaccharides as a significant strategy to survive in extreme conditions. The exopolysaccharides synthesized by extremophiles possess distinctive characteristics due to the varied harsh environments which stimulate the microorganisms to produce these biopolymers. Despite many bioprocesses have been designed to yield exopolysaccharides, the production of exopolysaccharides by extremophiles is inefficient compared with mesophilic and neutrophilic exopolysaccharide producers. Meanwhile, the industrial development of novel extremophilic exopolysaccharides remains constrained due to the lack of exploration. In this review, we summarize the structure and properties of various exopolysaccharides produced by extremophiles, and also discuss potential metabolic and genetic engineering strategies for enhanced yield and modified structure of extremophilic exopolysaccharides. Special focus is given to the applications of extremophilic exopolysaccharides in the areas of biomedicine, food industry, and biomaterials via nano-techniques, casting and electrospinning. [ABSTRACT FROM AUTHOR]

Abstract Exploring life cycles of fungi is insightful for understanding their basic biology and can highlight their ecology. Here, we dissected the sexual and asexual life cycles of the obligate alkalophilic ascomycete Sodiomyces alkalinus that thrives at extremely high pH of soda lakes. S. alkalinus develops acremonium-type asexual sporulation, commonly found in ascomycetous fungi. However, the sexual stage was unusual, featuring very early lysis of asci which release young ascospores inside a fruit body long before its maturation. In a young fruit body, a slimy matrix which originates from the combined epiplasm of asci and united cytoplasm of the pseudoparenchymal cells, surrounds pooled maturing ascospores. Upon maturity, the ascospores are forcibly released through a crack in the fruit body, presumably due to an increased turgor pressure. These features of the sexual stage development resemble the ones found in unrelated marine fungi, indicating convergent evolution of the trait. We hypothesise these developmental features of S. alkalinus to be adaptive in the conditions of periodically inundated rims of soda lakes where the fungus thrives. Highlights • First detailed study of life cycle of an alkalophilic fungus S odiomyces alkalinus. • An unusual sexual stage featuring a combined epiplasm within the fruiting body. • Sexual stage resembles that of marine fungi, indicating convergent evolution. [ABSTRACT FROM AUTHOR]

Abstract A novel procedure to recover lead, silver and gold from polymetallic sulphide ores, cleaner than the traditional hydrometallurgical route (hot brine leaching), is proposed. This process consists of a biooxidation stage, where sulphides are oxidised by the action of extremophiles, followed by an acid washing and a citrate leaching in which lead is recovered. The final solid obtained, mainly composed of quartz, is rich in silver and gold. This paper is focused on the biooxidation and the lead recovery of the black gossan, a polymetallic sulphide ore with valuable amounts of lead, silver and gold. Biooxidation performed with a mixed mesophilic culture (mainly Acidithiobacillus ferrooxidans) at 20% pulp density is able to dissolve the sulphide matrix, removing the gold refractory behaviour and producing jarosite, beaverite, gypsum and anglesite. A previous sulphuric acid washing of biooxidation residue greatly improves the lead recovery in the citrate stage. In the sulphuric acid washing, jarosite and beaverite are dissolved, being the most important variables the temperature and sulphuric acid concentration. The jarosite dissolution kinetics shows that the rate controlling step is the chemical reaction, with an activation energy of 86.4 kJ/mol. A linear relationship between the jarosite dissolved and lead recovered is found, reinforcing the necessity of a previous H 2 SO 4 washing. The optimal pH range for lead recovery in the citrate solution is 5–9. Pulp densities higher than 5% produces an unstable solution, precipitating a part of the lead. A negative effect of gypsum has been confirmed through several citrate leaching tests performed with pure anglesite. The solid obtained after the studied stages is suitable to recover gold and silver that contains. Graphical abstract Image 1 Highlights • An alternative approach is proposed to recover Pb, Ag and Au from sulphide ores. • For first time citrate leaching of a biooxidation residue is studied. • A H 2 SO 4 washing of bioleaching residue enhances Pb recovery in citrate leaching. • Temperature and H 2 SO 4 concentration are the mandatory variables in acid washing. • pH and pulp density play a key role in the citrate leaching. [ABSTRACT FROM AUTHOR]

A variety of extreme environments, characterized by extreme values of various physicochemical parameters (temperature, pressure, salinity, pH, and so on), are found on Earth. Organisms that favorably live in such extreme environments are called extremophiles. All living organisms, including extremophiles, must acquire energy to maintain cellular homeostasis, including extremophiles. For energy conversion in harsh environments, thermodynamically useful reactions and stable biomolecules are essential. In this review, I briefly summarize recent studies of extreme environments and extremophiles living in these environments and describe energy conversion processes in various extremophiles based on my previous research. Furthermore, I discuss the correlation between the biological system of electrotrophy, a third biological energy acquisition system, and the mechanism underlying microbiologically influenced corrosion. These insights into energy conversion in extremophiles may improve our understanding of the "limits of life". Abbreviations: PPi: pyrophosphate; PPase: pyrophosphatase; ITC: isothermal titration microcalorimetry; SVNTase: Shewanella violacea 5ʹ-nucleotidase; SANTase: Shewanella amazonensis 5ʹ-nucleotidase [ABSTRACT FROM AUTHOR]

Extreme environments such as the Antarctic can lead to the discovery of new microbial taxa, as well as to new microbial-derived natural products. Considering that little is known yet about the diversity and the genetic resources present in these habitats, the main objective of this study was to evaluate the fungal communities from extreme environments collected at Aldmiralty Bay (Antarctica). A total of 891 and 226 isolates was obtained from soil and marine sediment samples, respectively. The most abundant isolates from soil samples were representatives of the genera Leucosporidium, Pseudogymnoascus, and a non-identified Ascomycota NIA6. Metschnikowia sp. was the most abundant taxon from marine samples, followed by isolates from the genera Penicillium and Pseudogymnoascus. Many of the genera were exclusive in marine sediment or terrestrial samples. However, representatives of eight genera were found in both types of samples. Data from non-metric multidimensional scaling showed that each sampling site is unique in their physical-chemical composition and fungal community. Biotechnological potential in relation to enzymatic production at low/moderate temperatures was also investigated. Ligninolytic enzymes were produced by few isolates from root-associated soil. Among the fungi isolated from marine sediments, 16 yeasts and nine fungi showed lipase activity and three yeasts and six filamentous fungi protease activity. The present study permitted increasing our knowledge on the diversity of fungi that inhabit the Antarctic, finding genera that have never been reported in this environment before and discovering putative new species of fungi. [ABSTRACT FROM AUTHOR]

Microbes are the most abundant lifeforms on the planet and perform functions critical for all other life to exist. Environmental 'omic' technologies provide the capacity to discover the 'what, how and why' of indigenous species. However, in order to accurately interpret this data, sound conceptual frameworks are required. Here I argue that our understanding of microbes will advance much more effectively if we adopt a microbcentric, and not anthropocentric view of the world. [ABSTRACT FROM AUTHOR]

Trimatostroma salinum, Wallemia ichthyophaga, Hortaea werneckii and Phaeotheca triangularis are halophilic fungi, which can thrive in a wide range of salinity. They present a source of valuable bioactive compounds, enzymes and proteins interesting for food and pharmaceutical industry. To separate enzymes from halophilic fungi cells, the mechanical method was used. Obtained results and new findings are important from the biotechnological point of view, since the separation of in the form of cocktail from halophilic fungi is interesting for industrial applications, especially for cascade reactions. Enzymes from extremophiles namely possess improved properties and can be used at harsh conditions where non-extremophilic enzymes may deactivate. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Possibility of native microbes in deep Marcellus suggested, justifying further research. • More organisms found in produced water were also found in shale core samples. • Most organisms have attributes that may improve chances of survival in subsurface. • Some microbes in produced water suggested to originate from injected fluids. Abstract Marcellus Shale drilling is a relatively new activity that has expanded natural gas resources in the United States. Although many assumed Marcellus Shale was sterile due to extreme conditions endured since deposition, conditions present in the shale today are within range where microorganisms can occur. Here, we consider whether some microbes seen in produced fluids from Marcellus Shale drilling may be native by comparing organisms found in core samples and produced fluids to those found in injected fluids from active wells in Pennsylvania. Illumina sequencing was used to identify organisms based on 16s rRNA barcoding regions of DNA extracts from Marcellus Shale samples. Identified microbial communities were then compared using principal components analysis and SourceTracker tools. Frequency of homology between sequences showed that produced fluids contained more microorganisms in common with shale cores than with injected fluids. Principal components analysis and SourceTracker corroborated these results. Possible native organisms found in these samples included radiotolerant extremophiles such as Deinococcus radiodurans. This work suggests that deep subsurface Marcellus Shale, previously believed sterile, may contain native microorganisms, which may have been deposited during the original deposition or migrated into the deep subsurface Marcellus during a more recent water influx. Additional investigation is recommended. [ABSTRACT FROM AUTHOR]

Abstract Although second generation biofuel technology is a sustainable route for bioethanol production it is not currently a robust technology because of certain hindrances viz., unavailability of potential enzyme resources, low efficiency of enzymes and restricted availability of potent enzymes that work under harsh conditions in industrial processes. Therefore, bioprospecting of extremophilic microorganisms using metagenomics is a promising alternative to discover novel microbes and enzymes with efficient tolerance to unfavourable conditions and thus could revolutionize the energy sector. Metagenomics a recent field in "omics" technology enables the genomic study of uncultured microorganisms with the goal of better understanding microbial dynamics. Metagenomics in conjunction with NextGen Sequencing technology facilitates the sequencing of microbial DNA directly from environmental samples and has expanded, and transformed our knowledge of the microbial world. However, filtering the meaningful information from the millions of genomic sequences offers a serious challenge to bioinformaticians. The current review holds the opinion tool 'know- how' to unravel the secrets of nature while expediting the bio-industrial world. We also discuss the novel biocatalytic agents discovered through metagenomics and how bioengineering plays a pivotal role to enhance their efficiency. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The biological paradox about how extremophiles persist at extreme ecological conditions throws a fascinating picture of the enormous potential of a single cell to adapt to homeostatic conditions in order to propagate. Unicellular organisms face challenges from both environmental factors and the ecological niche provided by the host tissue. Although the existence of extremophiles and their physiological properties were known for a long time, availability of whole genome sequence has catapulted the study on mechanisms of adaptation and the underlying principles that have enabled these unique organisms to withstand evolutionary and environmental pressures. Comparative genomics has shown that extremophiles possess the unique set of genes and proteins that empower them with biochemical machinery necessary to thrive in extreme environments. The presence of these proteins safeguards the cell against a wide array of extreme conditions such as temperature, pressure, radiations, chemicals, drugs etc. An insight into these adaptive mechanisms in extremophiles may help us to devise strategies to alter the genes and proteins that may have therapeutic potential and commercial value. Here we present an overview of the various adaptations in extremophiles. We also try to explain how mycobacterium channelizes its proteome to survive in stress conditions posed by host immune system. [ABSTRACT FROM AUTHOR]

Abstract Discovering how organisms and their proteins adapt to extreme conditions is a complicated process. Every condition has its own set of adaptations that make it uniquely stable in its environment. The purpose of our review is to discuss what is known in the extremophilic community about protein adaptations. To simplify our mission, we broke the extremophiles into three broad categories: thermophiles, halophiles and psychrophiles. While there are crossover organisms- organisms that exist in two or more extremes, like heat plus acid or cold plus pressure, most of them have a primary adaptation that is within one of these categories which tends to be the most easily identifiable one. While the generally known adaptations are still accepted, like thermophilic proteins have increased ionic interactions and a hardier hydrophobic core, halophilic proteins have a large increase in acidic amino acids and amino acid/peptide insertions and psychrophiles have a much more open structure and reduced ionic interactions, some new information has come to light. Thermophilic stability can be improved by increased subunit-subunit or subunit-cofactor interactions. Halophilic proteins have reversible folding when in the presence of salt. Psychrophilic proteins have an increase in cavities that not only decrease the formation of ice, but also increase flexibility under low temperature conditions. In a proof of concept experiment, we applied what is currently known about adaptations to a well characterized protein, malate dehydrogenase (MDH). While this protein has been profiled in the literature, we are applying our adaptation predictions to its sequence and structure to see if the described adaptations apply. Our analysis demonstrates that thermophilic and halophilic adaptations fit the corresponding MDHs very well. However, because the number of psychrophiles MDH sequences and structures is low, our analysis on psychrophiles is inconclusive and needs more information. By discussing known extremophilic adaptations and applying them to a random, conserved protein, we have found that general adaptations are conserved and can be predicted in proposed extremophilic proteins. The present field of extremophile adaptations is discovering more and more ways organisms and their proteins have adapted. The more that is learned about protein adaptation, the closer we get to custom proteins, designed to fit any extreme and solve some of the world's most pressing environmental problems. [ABSTRACT FROM AUTHOR]

Bio-based industries require stable enzymes in a broad range of environmental conditions. Extremophiles have attracted more interests as the source of such enzymes, one of which is α-amylase. This study aimed to purify and characterize α-amylase produced by a thermo-halophilic bacterium PLS 75 isolated from underwater fumaroles. Ammonium sulfate precipitation results showed that the highest specific α-amylase activity (21.7 U/mg) obtained at 40-60% saturation level, with a purity of 7.7-fold of the crude extract with 16.2% yield. Further purification using DEAE Sepharose column chromatography increased the enzyme purity 11.1-fold of the crude extract with 7.1% yield. Specific activity after column chromatography purification was 31.3 U/mg. The pure enzyme had a low molecular weight of 14 kDa. The enzyme showed the highest activity at 80 °C and pH 5. The activity increased to 126% when in methanol, while decreased when in ethyl acetate and chloroform. The characteristics of α-amylase with low molecular weight, which was active in acidic condition, stable in polar and non-polar solvents, may be used for for specific industrial needs. [ABSTRACT FROM AUTHOR]

The high-altitude atmosphere is a harsh environment with extremely low temperatures, low pressure, and high UV irradiation. For this reason, it has been proposed as an analogue for Mars, presenting deleterious factors similar to the surface of this planet. We evaluated the survival of extremophilic UV-resistant yeasts isolated from a high elevation area in the Atacama Desert to stratosphere conditions. As biological controls, intrinsically resistant Bacillus subtilis spores were used. Experiments were performed in two independent stratospheric balloon flights and with an environmental simulation chamber. Three different conditions were evaluated: (1) desiccation; (2) desiccation plus exposure to stratospheric low pressure and temperature; (3) desiccation plus exposure to the full stratospheric environment (UV, low pressure and temperature). Two strains, Naganishia (Cryptococcus) friedmannii 16LV2 and Exophiala sp. 15LV1 survived full exposures to the stratosphere, in larger numbers than B. subtilis spores. Holtermanniella watticus 16LV1, however, suffered substantial loss of viability upon desiccation and did not survive the stratospheric UV exposure. The remarkable resilience of N. friedmannii and Exophiala sp. to the extreme, Mars-like conditions of the stratosphere confirms its potential as eukaryotic models for astrobiology. Additionally, our results with N. friedmannii strengthen the recent hypothesis that yeasts belonging to this genus are fit for aerial dispersion, which might account for the observed abundance of this species in high elevation soils. [ABSTRACT FROM AUTHOR]

Abstract Esterases and lipases from extremophiles have attracted great attention due to their unique characteristics and wide applications. In the present study, an open reading frame (ORF) encoding a novel cold active esterase (EstN7) from Bacillus cohnii strain N1 was cloned and expressed in Escherichia coli. The full-length esterase gene encoding a protein of 320 amino acids with estimated molecular weight of 37.0 kDa. Amino acid sequence analysis revealed that the EstN7 belongs to family IV lipases with a characteristic penta-peptide motif (GXSXG), the catalytic triad Ser, Asp, His and the conserved HGGG motif of the family IV. The recombinant enzyme was purified to apparent homogeneity using nickel-affinity chromatography with a purification fold of 5 and recovery 94.5%. The specific activity of the purified enzyme was 336.89 U/mg. The recombinant EstN7 showed optimal activity at 5 °C moreover, EstN7 displayed full robust stability in the presence of wide range of organic solvents. The purified enzyme had K m and V max of 45 ± 0.019 μM and 1113 μmol min−1 mg−1, respectively on p -NP-acetate. These promising characteristics of the recombinant EstN7 would underpin its possible usage with high potential in the synthesis of fragile compounds in pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Aim: This study aimed at unprecedented physical and chemical evaluation of the 'green plastics' polyhydroxyalkanoates (PHAs), in an extremely halotolerant Halomonas elongata strain 2FF under high‐salt concentration. Methods and Results: The investigated bacterial strain was isolated from the surface water of the hypersaline Fără Fund Lake. The 16S rRNA gene sequence phylogeny and phenotypic analysis indicated that the isolate belonged to H. elongata. PHA inclusions were observed by Sudan Black B, Nile Red staining, and transmission electron microscopy during growth at high salinity (10%, w/v, NaCl) on 1% (w/v) d‐glucose. The produced polymer was quantitatively and qualitatively assessed using crotonic acid assay, elemental analysis, Fourier transform infrared and Raman spectroscopies. Additionally, X‐ray powder diffraction, 1H‐NMR spectroscopy, and differential scanning calorimetry were applied. The investigations showed that the intracellular polymer was polyhydroxybutyrate (PHB) of which the strain produced up to 40 wt% of total cell dry weight after 48 h. The analysis of phaC gene from the isolated H. elongata strain indicated that the encoded PHA synthase belongs to Class I PHA synthase family. Conclusions: Overall, our investigations pointed out that the halotolerant H. elongata strain 2FF was capable to produce significant amounts of PHB from d‐glucose, and PHAs from various carbon substrates at high‐salt concentrations. Significance and Impact of the Study: The tested strain showed the ability for significant production of natural, biodegradable polymers under nutrient limitation and hypersaline conditions suggesting its potentiality for further metabolic and molecular investigations towards enhanced biopolymer production. Additionally, this study reports on the unprecedented use of Raman and XPRD techniques to investigate PHAs of an extremely halotolerant bacterium, thus expanding the repertoire of physical methods to study green plastics derived from extremophilic microorganisms. [ABSTRACT FROM AUTHOR]

The present study proposes to search our solar system (Mars, Enceladus, Europa) for patterns of organic molecules that are universally associated with biological functions and structures. The functions are primarily catalytic because life could only have originated within volume/space-constrained compartments containing chemical reactions catalyzed by certain polymers. The proposed molecular structures are specific groups in the side chains of amino acids with the highest catalytic propensities related to life on Earth, that is, those that most frequently participate as key catalytic groups in the active sites of enzymes such as imidazole, thiol, guanidinium, amide, and carboxyl. Alternatively, these or other catalytic groups can be searched for on non-amino-acid organic molecules, which can be tested for certain hydrolytic catalytic activities. The first scenario assumes that life may have originated in a similar manner as the terrestrial set of α-amino acids, while the second scenario does not set such a requirement. From the catalytic propensity perspective proposed in the first scenario, life must have invented amino acids with high catalytic propensity (His, Cys, Arg) in order to overcome, and be complemented by, the low catalytic propensity of the initially available abiogenic amino acids. The abiogenic and the metabolically invented amino acids with the lowest catalytic propensity can also serve as markers of extraterrestrial life when searching for patterns on the basis of the following functional propensities related to protein secondary/quaternary structure: (1) amino acids that are able to form α-helical intramembrane peptide domains, which can serve as primitive transporters in protocell membrane bilayers and catalysts of simple biochemical reactions; (2) amino acids that tend to accumulate in extremophile proteins of Earth and possibly extraterrestrial life. The catalytic/structural functional propensity approach offers a new perspective in the search for extraterrestrial life and could help unify previous amino acid–based approaches. [ABSTRACT FROM AUTHOR]

Polar volcanoes harbor unique conditions of extreme temperature gradients capable of selecting different types of extremophiles. Deception Island is a marine stratovolcano located at Maritime Antarctica that is notable for its pronounced temperature gradients over very short distances, reaching values up to 100 °C in the fumaroles, and subzero temperatures next to the glaciers. Due to these characteristics, Deception can be considered an interesting analogue of extraterrestrial environments. Our main goal in this study was to isolate thermophilic and psychrophilic bacteria from sediments associated with fumaroles and glaciers from two geothermal sites in Deception Island, comprising temperatures between 0 and 98 °C, and to evaluate their survivability to desiccation and UV-C radiation. Our results revealed that culturable thermophiles and psychrophiles were recovered among the extreme temperature gradient in Deception volcano, which indicates that these extremophiles remain alive even when the conditions do not comprise their growth range. The viability of culturable psychrophiles in hyperthermophilic environments is still poorly understood and our work showed the importance of future studies about their survival strategies in high temperatures. Finally, the spore-forming thermophilic isolates which we found have displayed good survival to desiccation and UV-C irradiation, which suggests their potential to be further explored in astrobiological studies. [ABSTRACT FROM AUTHOR]

Alkaliphilic organisms are among an industrially important class of extremophile microorganisms with the ability to thrive at pH 10–11.5. Microorganisms that exhibit alkaliphilic characteristics are sources of alkali-tolerant enzymes such as proteases, starch degrading enzymes, cellulases, and metabolites such as antibiotics, enzyme inhibitors, siderophores, organic acids, and cholic acid derivatives, which have found various applications in industry for human and environmental health. Yet, multi-omics mechanisms governing adaptation to high alkalinity have been poorly studied. We undertook the present work to understand, as a case study, the alkaliphilic adaptation strategy of the novel microorganism, Bacillus marmarensis DSM 21297, to alkaline conditions using a multi-omics approach that employed transcriptomics and proteomics. As alkalinity increased, bacteria remodeled the peptidoglycan layer by changing peptide moieties along with the peptidoglycan constituents and altered the cell membrane to reduce lipid motility and proton leakiness to adjust intracellular pH. Different transporters also contributed to the maintenance of this pH homeostasis. However, unlike in most well-known alkaliphiles, not only sodium ions but also potassium ions were involved in this process. Interestingly, increased pH has triggered the expression of neither general stress proteins nor gene encoding proteins associated with heat, salt, and nutrient stresses. Only an increase in the expression of oxidative stress related genes was evident. Endospore formation, also a phenomenon closely linked to stress, was unclear. This questioned if high pH was a real stress for B. marmarensis. These new findings, corroborated using the multi-omics approach of the present case study, broaden the knowledge on the mechanisms of alkaliphilic adaptation and might also potentially offer useful departure points for further industrial applications with other microorganisms. [ABSTRACT FROM AUTHOR]

This study constitutes the first-proof-of-concept of a methane biorefinery based on the multi-production of high profit margin substances (ectoine, hydroxyectoine, polyhydroxyalkanoates (PHAs) and exopolysaccharides (EPS)) using methane as the sole carbon and energy source. Two bubble column bioreactors were operated under different magnesium concentrations (0.2, 0.02 and 0.002 g L −1 ) to validate and optimize this innovative strategy for valorization of CH 4 emissions. High Mg 2+ concentrations promoted the accumulation of ectoine (79.7–94.2 mg g biomass −1 ), together with high hydroxyectoine yields (up to 13 mg g biomass −1 ) and EPS concentrations (up to 2.6 g L culture broth −1 ). Unfortunately, PHA synthesis was almost negligible (14.3 mg L −1 ) and only found at the lowest Mg 2+ concentration tested. Halomonas, Marinobacter, Methylophaga and Methylomicrobium , previously described as ectoine producers, were dominant in both bioreactors, Methylomicrobium being the only described methanotroph . This study encourages further research on CH 4 biorefineries capable of creating value out of GHG mitigation. [ABSTRACT FROM AUTHOR]

Scytonemin is a pigment synthesized by cyanobacteria and found in their sheath. The importance of this biomolecule is its photoprotective function, which is one of the major survival strategies adopted by extremophiles under stressed conditions. Scytonemin has been identified as a prime biomarker in the search for past or present life on planetary surfaces and subsurfaces. This work proposes two new structures, each consisting of two scytonemin molecules forming a sandwich complex with iron III. The Raman wave numbers for the proposed structures are predicted computationally using DFT calculations. The predicted bands are reported in relation to structural changes that take place upon complex formation. The complexes may be identified by comparing their Raman spectra to that of the parent scytonemin. This information is intended to widen the search for experimental evidence for scytonemin molecules forming iron complexes, novel biosignatures for the extremophilic colonization of terrestrial iron-rich terrains with potential analogues for robotic exploration of Mars. [ABSTRACT FROM AUTHOR]

Biological materials that are genetically encoded and can self-assemble offer great potential as immobilization platforms in industrial biocatalysis. Protein-based scaffolds can be used for the spatial organization of enzymes, to stabilize the catalysts and provide optimal microenvironments for reaction sequences. In our previous work, we created a protein scaffold for enzyme localization by engineering the bacterial microcompartment shell protein EutM from Salmonella enterica. Here, we sought to expand this work by developing a toolbox of EutM proteins with different properties, with the potential to be used for future immobilization of enzymes. We describe the bioinformatic identification of hundreds of homologs of EutM from diverse microorganisms. We specifically select 13 EutM homologs from extremophiles for characterization, based on phylogenetic analyses. We synthesize genes encoding the novel proteins, clone and express them in E. coli, and purify the proteins. In vitro characterization shows that the proteins self-assemble into robust nano- and micron-scale architectures including protein nanotubes, filaments, and scaffolds. We explore the self-assembly characteristics from a sequence-based approach and create a synthetic biology platform for the coexpression of different EutM homologs as hybrid scaffolds with integrated enzyme attachment points. This work represents a step towards our goal of generating a modular toolbox for the rapid production of self-assembling protein-based materials for enzyme immobilization. [ABSTRACT FROM AUTHOR]

The goal of this research was to generate networks of co-expressed genes to explore the genomic responses of Rhizophora mangle L. populations to contrasting environments and to use gene network analysis to investigate their capacity for adaptation in the face of historical and future perturbations and climatic changes. RNA sequencing data were generated for R. mangle samples collected under field conditions from contrasting climate zones in the equatorial and subtropical regions of Brazil. A gene co-expression network was constructed using Pearson's correlation coefficient, showing correlations among 78,364 transcriptionally coordinated genes. Each region exhibited two distinct network profiles; genes correlated with the oxidative stress response showed higher relative expression levels in subtropical samples than in equatorial samples, whereas genes correlated with the hyperosmotic salinity response, heat response and UV response had higher expression levels in the equatorial samples than in the subtropical samples. In total, 992 clusters had enriched ontology terms, which suggests that R. mangle is under higher stress in the equatorial region than in the subtropical region. Increased heat may thus pose a substantial risk to species diversity at the center of its distribution range in the Americas. This study, which was performed using trees in natural field conditions, allowed us to associate the specific responses of genes previously described in controlled environments with their responses to the local habitat where the species occurs. The study reveals the effects of contrasting environments on gene expression in R. mangle , shedding light on the different abiotic variables that may contribute to the genetic divergence previously described for the species through the use of simple sequence repeats (SSRs). These effects may result from two fundamental processes in evolution, namely, phenotypic plasticity and natural selection. [ABSTRACT FROM AUTHOR]

Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA , and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival. [ABSTRACT FROM AUTHOR]

Due to their similarity to natural counterparts, nucleic acid derivatives (nucleobases, nucleosides, and nucleotides, among others) are interesting molecules for pharmaceutical, biomedical, or food industries. For this reason, there is increasing worldwide demand for the development of efficient synthetic processes for these compounds. Chemical synthetic methodologies require numerous protection-deprotection steps and often lead to the presence of undesirable by-products or enantiomeric mixtures. These methods also require harsh operating conditions, such as the use of organic solvents and hazard reagents. Conversely, enzymatic production by whole cells or enzymes improves regio-, stereo-, and enantioselectivity and provides an eco-friendly alternative. Because of their essential role in purine and pyrimidine scavenging, enzymes from purine and pyrimidine salvage pathways are valuable candidates for the synthesis of many different nucleic acid components. In recent years, many different enzymes from these routes, such as nucleoside phosphorylases, nucleoside kinases, 2′-deoxyribosyltransferases, phosphoribosyl transferases, or deaminases, have been successfully employed as biocatalysts in the production of nucleobase, nucleoside, or nucleotide analogs. Due to their great activity and stability at extremely high temperatures, the use of enzymes from thermophiles in industrial biocatalysis is gaining momentum. Thermophilic enzymes not only display unique characteristics such as temperature, chemical, and pH stability but also provide many different advantages from an industrial perspective. This mini-review aims to cover the most representative enzymatic approaches for the synthesis of nucleic acid derivatives. In this regard, we provide detailed comments about enzymes involved in crucial steps of purine and pyrimidine salvage pathways in thermophiles, as well as their biological role, biochemical characterization, active site mechanism, and substrate specificity. In addition, the most interesting synthetic examples reported in the literature are also included. [ABSTRACT FROM AUTHOR]

Over geologic time, the water in the Bonneville basin has risen and  fallen, most dramatically as freshwater Lake Bonneville lost enormous volume 15,000-13,000 years ago and became the modern day Great Salt Lake. It is likely that paleo-humans lived along the shores of this body of water as it shrunk to the present margins, and native peoples inhabited the surrounding desert and wetlands in recent times. Nineteenth century Euro-American explorers and pioneers described the geology, geography, and flora and fauna of Great Salt Lake, but their work attracted white settlers to Utah, who changed the lake immeasurably. Human intervention in the 1950s created two large sub-ecosystems, bisected by a railroad causeway. The north arm approaches ten times the salinity of sea water, while the south arm salinity is a meager four times that of the oceans. Great Salt Lake was historically referred to as sterile, leading to the nickname “America’s Dead Sea.” However, the salty brine is teaming with life, even in the hypersaline north arm. In fact, scientists have known that this lake contains a diversity of microscopic lifeforms for more than 100 years. This essay will explore the stories of the people who observed and researched the salty microbiology of Great Salt Lake, whose discoveries demonstrated the presence of bacteria, archaea, algae, and protozoa that thrive in this lake. These scientists documented the lake’s microbiology as the lake changed, with input from human waste and the creation of impounded areas. Modern work on the microbiology of Great Salt Lake has added molecular approaches and illuminated the community structures in various regions, and fungi and viruses have now been described. The exploration of Great Salt Lake by scientists describing these tiny inhabitants of the brine illuminate the larger terminal lake with its many facets, anthropomorphic challenges, and ever-changing shorelines. [ABSTRACT FROM AUTHOR]