Viruses are the most abundant biological entities in the biosphere, and have the ability to infect Bacteria, Archaea, and Eukaryotes. The virome is estimated to be at least ten times more abundant ...than the microbiome with 10
7
viruses per milliliter and 10
9
viral particles per gram in marine waters and sediments or soils, respectively. Viruses represent a largely unexplored genetic diversity, having an important role in the genomic plasticity of their hosts. Moreover, they also play a significant role in the dynamics of microbial populations. In recent years, metagenomic approaches have gained increasing popularity in the study of environmental viromes, offering the possibility of extending our knowledge related to both virus diversity and their functional characterization. Extreme environments represent an interesting source of both microbiota and their virome due to their particular physicochemical conditions, such as very high or very low temperatures and >1 atm hydrostatic pressures, among others. Despite the fact that some progress has been made in our understanding of the ecology of the microbiota in these habitats, few metagenomic studies have described the viromes present in extreme ecosystems. Thus, limited advances have been made in our understanding of the virus community structure in extremophilic ecosystems, as well as in their biotechnological potential. In this review, we critically analyze recent progress in metagenomic based approaches to explore the viromes in extreme environments and we discuss the potential for new discoveries, as well as methodological challenges and perspectives.
Nature exhibits an enormous diversity of organisms that thrive in extreme environments. From snow algae that reproduce at sub-zero temperatures to radiotrophic fungi that thrive in nuclear radiation ...at Chernobyl, extreme organisms raise many questions about the limits of life. Is there any environment where life could not “find a way”? Although many individual extremophilic organisms have been identified and studied, there remain outstanding questions about the limits of life and the extent to which extreme properties can be enhanced, combined or transferred to new organisms. In this review, we compile the current knowledge on the bioengineering of extremophile microbes. We summarize what is known about the basic mechanisms of extreme adaptations, compile synthetic biology’s efforts to engineer extremophile organisms beyond what is found in nature, and highlight which adaptations can be combined. The basic science of extremophiles can be applied to engineered organisms tailored to specific biomanufacturing needs, such as growth in high temperatures or in the presence of unusual solvents.
An effective biosurfactant producer and extremophiles bacteria,
Bacillus cereus
KH1, was isolated from textile effluent and the biosurfactant was produced using molasses as the sole carbon source. ...Growth parameters such as pH, temperature, salinity and concentration of molasses were optimised for decolourising the textile effluent with 24-h incubation. The biosurfactant property of
B. cereus
KH1 was evaluated based on haemolytic activity, oil displacement technique, drop-collapsing test and emulsification index. The results of the produced biosurfactant showed a positive reaction in haemolytic activity, oil displacement technique, drop-collapsing test and exhibiting a 67% emulsification index. The cell-free broth was stable in 40 °C pH 7, 7% salinity and 7% molasses. Thin-Layer Chromatography and Fourier Transform Infrared Spectroscopy analysis revealed that the biosurfactant was a lipopeptide with a yield 2.98 g L
−1
. These findings proved the synergistic action of
B. cereus
KH1 with lipopeptide biosurfactant may accelerated the decolourisation efficiency to 87%.
Space exposure experiments from the last 15 years have unexpectedly shown that several terrestrial organisms, including some multi-cellular species, are able to survive in open space without ...protection. The robustness of bdelloid rotifers suggests that these tiny creatures can possibly be added to the still restricted list of animals that can deal with the exposure to harsh condition of space. Bdelloids are one of the smallest animals on Earth. Living all over the world, mostly in semi-terrestrial environments, they appear to be extremely stress tolerant. Their desiccation tolerance at any stage of their life cycle is known to confer tolerance to a variety of stresses including high doses of radiation and freezing. In addition, they constitute a major scandal in evolutionary biology due to the putative absence of sexual reproduction for at least 60 million years.
Adineta vaga
, with its unique characteristics and a draft genome available, was selected by ESA (European Space Agency) as a model system to study extreme resistance of organisms exposed to space environment. In this manuscript, we documented the resistance of desiccated
A. vaga
individuals exposed to increasing doses of X-ray, protons and Fe ions. Consequences of exposure to different sources of radiation were investigated in regard to the cellular type including somatic (survival assay) and germinal cells (fertility assay). Then, the capacity of
A. vaga
individuals to repair DNA DSB induced by different source of radiation was investigated. Bdelloid rotifers represent a promising model in order to investigate damage induced by high or low LET radiation. The possibility of exposure both on hydrated or desiccated specimens may help to decipher contribution of direct and indirect radiation damage on biological processes. Results achieved through this study consolidate our knowledge about the radioresistance of
A. vaga
and improve our capacity to compare extreme resistance against radiation among living organisms including metazoan.
Industrial residues with high concentrations of hexavalent chromium Cr(VI), characterized by an alkaline pH (between 9 and 13) and high salinity (around 100 psu), were used as a source for ...extremophilic chromium-resistant and -reducing microorganisms. An investigation of biodiversity through MiSeq showed the presence of 20 bacterial classes, with Bacilli (47%), Negativicutes (15%), Bacteriodia (8%), Gammaproteobacteria (7%) and Clostridia (5%) being the most abundant. The bioprospection allowed the cultivation of 87 heterotrophic bacterial colonies and 17 bacterial isolates at the end of the isolation, and screening procedures were obtained. The isolates were related to Cellulosimicrobium aquatile, C. funkei, Acinetobacter radioresistens, Staphylococcus equorum, S. epidermis, Brachybacterium paraconglometratum, Glutamicibacter creatinolyticus, Pseudomonas songnenensis, Microbacterium algeriense and Pantoea eucalypti, most of them being resistant to Cr(VI). Resistances of up to 400 mg.L−1 of chromate were obtained for four related strains (QReMLB55A, QRePRA55, QReMLB33A and QReMLB44C). The C. aquatile strain QReMLB55A and the P. songnenensis strain QReMLB33A were exposed to K2Cr2O7 (200 mg.L−1) under optimal conditions, diminishing 94% and 24% of the Cr(VI) in 6 days, respectively. These strains exhibited a high potential for chromium remediation biotechnologies.
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
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
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:
and
Motility);
and
(transport);
, and
(compatible solutes);
y
(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.
•Extremophiles isolation and molecular characterization.•Epifluorescence microscopy for the viability.•Isolation and characterization of exopolysaccharide.•ICP-MS analysis of Lead ...remediation.•Industrially applicable testing for wastewater treatment.
Lead released from manufacturing factories, recycling plants, automobile company and landfill leachate is abundantly found in wastewater. An efficient bioremediating agent for lead removal from wastewater is expected to ease the ever increasing problem. The present study reports Pseudomonas sp. W6 isolated from extreme habitat of hot water spring of North–East India evaluated for its Lead biosorption property. The bacterium showed capacity to resist 1.0mM lead in both solid and liquid minimal media. Epifluorescence microscopy reveal the viability of bacterial cells under metal stress condition. ICP-MS analysis revealed 65% and 61.2% removal of lead from the Synthetic Bangladesh Ground Water medium in batch culture and column study respectively which was higher when compared to biosorption capacity of P. aeruginosa MTCC2474, P. alcaligenes MJ7 from forest soil and P. ficuserectae PKRS11 from uranium rich soil. Exopolysaccharide released by the isolate which influenced biosorption revealed the presence of ligands assayed using microbial hydrophobicity and FTIR. The extremophilic isolate is proposed as a choice for efficient bioremediation of lead contaminated wastewater.
Leaf mineral composition, the leaf ionome, reflects the complex interaction between a plant and its environment including local soil composition, an influential factor that can limit species ...distribution and plant productivity. Here we addressed within-species variation in plant–soil interactions and edaphic adaptation using Arabidopsis halleri, a well-suited model species as a facultative metallophyte and metal hyperaccumulator.
We conducted multi-element analysis of 1972 paired leaf and soil samples from 165 European populations of A. halleri, at individual resolution to accommodate soil heterogeneity. Results were further confirmed under standardized conditions upon cultivation of 105 field-collected genotypes on an artificially metal-contaminated soil in growth chamber experiments.
Soil-independent between- and within-population variation set apart leaf accumulation of zinc, cadmium and lead from all other nutrient and nonessential elements, concurring with differential hypothesized ecological roles in either biotic interaction or nutrition. For these metals, soil–leaf relationships were element-specific, differed between metalliferous and non-metalliferous soils and were geographically structured both in the field and under standardized growth conditions, implicating complex scenarios of recent ecological adaptation.
Our study provides an example and a reference for future related work and will serve as a basis for the molecular–genetic dissection and ecological analysis of the observed phenotypic variation.
•A β-glucosidase from Alicyclobacillus acidiphilus (AacGH1) is described.•The crystal structure of AacGH1 has been solved and refined to 1.55 Å resolution.•AacGH1 tolerates high concentrations of ...glucose, fructose, and ethanol.•AacGH1 rapidly hydrolyses glucovanillin to vanillin in 20 % ethanol.•AacGH1 has been applied to the production of vanillin directly from green vanilla.
Current methods for the production of natural vanilla extract are long and tedious, and the efficiency of the vanillin extraction is usually conditioned by different factors during the traditional curing process (temperatures and weather conditions). As an important fraction of vanillin is present in the form of glucovanillin in green beans, endogenous β-glucosidases contribute to its hydrolysis; however, these enzymes lose efficiency during the curing process. The use of extremophilic organisms as a source of an appropriate exogenous enzyme can offer a valid alternative when producing natural vanillin. Here, a β-glucosidase from the thermo-acidophilic organism Alicyclobacillus acidiphilus (AacGH1) was cloned, expressed in E. coli BL21, and fully characterized in respect to both function and crystal structure. Notably, AacGH1 was stable at a temperature up to 50 °C and exhibited good tolerance to glucose, fructose and organic solvents, in particular it maintained full activity in the presence of up to 20 % (v/v) ethanol. The enzyme was then successfully applied to an ethanol-water (20 % (v/v)) extract of green vanilla beans and the complete hydrolysis of glucovanillin (1.7 mM) to vanillin, and other flavour compounds commonly found in vanilla, was achieved using 0.5 mg/mL of enzyme in just 15 min at 30 °C.
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