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•Cyanidium caldarium (Cc) showed greatest As(III) sorption capacity (83.2 mg g−1).•Complexes of As(III)/As(V)-polysaccharide and As(III)-cysteine were found on cells.•No As(V) was ...detected within the Cyanidiales cells.•Arsenite was fixed by extracellular polysaccharides or transported into the cells.•New insights for Cyanidiales to bypass As(V) uptake, reduction, and methylation.
Addressing geogenic and anthropogenic arsenic (As) pollution is critical for environmental health. This study explored arsenite As(III) removal using Cyanidiales, particularly Cyanidium caldarium (Cc) and Galdieria partita (Gp), under acidic to neutral pH, and determined As(III) detoxification mechanisms in relation to As speciation and protein secondary structure in Cyanidiales. Regarding As(III) sorption amounts, Cc outperformed Gp, reaching 83.2 mg g−1 of removal at pH 5.0. Wherein, 23.5 % of sorbed As on Cc presented as arsenate As(V) complexation with polysaccharides, alongside other predominant species including As(III)-cysteine (41.2 %) and As(III)-polysaccharides (35.3 %) complexes. This suggested that As(III) was directly transported into cells, rather than As(V). Coupled with the formation of As(III)-cysteine complexes within cells, these mechanisms may be key to efficiently accumulating As(III) in Cyanidiales during the 6-h incubation. These results highlight the potential of Cyanidiales for sustainable As(III) remediation and provide new insights into managing As(III) toxicity.
The molecular basis of convergent phenotypes is often unknown. However, convergence at a genomic level is predicted when there are large population sizes, gene flow among diverging lineages or strong ...genetic constraints. We used whole-genome resequencing to investigate genomic convergence in fishes ( Poecilia spp.) that have repeatedly colonized hydrogen sulfide (H
S)-rich environments in Mexico. We identified genomic similarities in both single nucleotide polymorphisms (SNPs) and structural variants (SVs) among independently derived sulfide spring populations, with approximately 1.2% of the genome being shared among sulfidic ecotypes. We compared these convergent genomic regions to candidate genes for H
S adaptation identified from transcriptomic analyses and found that a significant proportion of these candidate genes (8%) were also in regions where sulfidic individuals had similar SNPs, while only 1.7% were in regions where sulfidic individuals had similar SVs. Those candidate genes included genes involved in sulfide detoxification, the electron transport chain (the main toxicity target of H
S) and other processes putatively important for adaptation to sulfidic environments. Regional genomic similarity across independent populations exposed to the same source of selection is consistent with selection on standing variation or introgression of adaptive alleles across divergent lineages. However, combined with previous analyses, our data also support that adaptive changes in mitochondrially encoded subunits arose independently via selection on de novo mutations. Pressing questions remain on what conditions ultimately facilitate the independent rise of adaptive alleles at the same loci in separate populations, and thus, the degree to which evolution is repeatable or predictable. This article is part of the theme issue 'Convergent evolution in the genomics era: new insights and directions'.
Cyanobacteria that grow above seawater salinity at temperatures above 45°C have rarely been studied.The present study is an attempt to decipher these unknown facts where the unique properties of ...phosphatase enzymes in a thermo-halotolerant Iceland clone 2 Leptolyngbyahas been studied under some important environmental conditions that play a distinctive rolein the growth of these extremophiles in those adverse ecological niches. Leptolyngbyaused in this present study is a unique species having 2 extreme characteristics of tolerance to high salt concentrations and temperature, so it is of intrinsic and scientific interest to study the phosphate dynamics and its variability under different ecological factors.The results of these experiments clearly show that under very adverse conditions of low light or high temperature and very high salt concentrations (almost 3 times of salt present in seawater 90g/L) this extremophile has the capacity to maintain its growth and metabolism which is the key to its survival in these extreme habitats.Observations from growth experiments under different environmental conditions(Temperatures, pH, salt concentrations, different light intensities) under laboratory conditions were found to be like its diverse patterns and adaptive ability in the extreme environment this organism has been isolated from. Phosphatase activity as a wayof understanding how P is metabolized under extreme conditions revealed that the highest phosphatase activity was observed in high salt concentrations (3 times that of seawater) and high temperatures of 45°C and low light intensities that is a very significant observation and scientifically important.
•Transition of the oil-based economy to a bioeconomy is expected to solve current global challenges.•Biotechnology plays a key role in this transformation towards a sustainable biobased ...industry.•Benefits of extremozymes have been recognized for several industrial applications.•Increasing numbers of robust biocatalysts are identified by sophisticated “omics” analyses.
The transition of the oil-based economy towards a sustainable economy completely relying on biomass as renewable feedstock requires the concerted action of academia, industry, politics and civil society. An interdisciplinary approach of various fields such as microbiology, molecular biology, chemistry, genetics, chemical engineering and agriculture in addition to cross-sectional technologies such as economy, logistics and digitalization is necessary to meet the future global challenges. The genomic era has contributed significantly to the exploitation of naturés biodiversity also from extreme habitats. By applying modern technologies it is now feasible to deliver robust enzymes (extremozymes) and robust microbial systems that are active at temperatures up to 120°C, at pH 0 and 12 and at 1000bar. In the post-genomic era, different sophisticated “omics” analyses will allow the identification of countless novel enzymes regardless of the lack of cultivability of most microorganisms. Furthermore, elaborate protein-engineering methods are clearing the way towards tailor-made robust biocatalysts. Applying environmentally friendly and efficient biological processes, terrestrial and marine biomass can be converted to high value products e.g. chemicals, building blocks, biomaterials, pharmaceuticals, food, feed and biofuels. Thus, further application of extremophiles has the potential to improve sustainability of existing biotechnological processes towards a greener biobased industry.
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•HGbI, a hemeprotein from extremophile, exhibits very low electrochemical potential.•Electrochemistry data indicated a pKa of 6.9 associated with an unknown sixth ligand.•Cyanide and ...imidazole bind unusually well to ferrous HGbI.•HGbI might be involved in redox-related catalytical processes.
Methylacidiphilum infernorum is a methanotroph bacterium that survives under extreme temperature and pH conditions in which five globins were identified. Among them, Hell’s Gate Globin I (HGbI) is a hemeprotein that presents peculiar features if compared to other globins, like stability at pH 2.8, very high oxygen affinity, and pH-dependent hexacoordination. All these features are likely related to the FeIII/II ion of the heme group whose redox behavior needs to be understood. Herein, we present the spectroelectrochemical determination of the redox potential of the HGbI protein in the absence and presence of relevant heme-binding molecules (cyanide, imidazole, carbon monoxide, nitric oxide and oxygen) in solution and also at different pH values (3.5 to 9.5). The spectroelectrochemical studies were performed giving midpoint redox potential (Em) values of −305, −338, and −442 mV vs normal hydrogen electrode (NHE) for the HGbI unliganded protein and bonded to imidazole and cyanide, respectively. The impressive negative value of the unliganded HGbI indicates it is very improbable to keep it reduced for binding and/or store O2. Interestingly, it was noticed an unusual high affinity of ferrous HGbI to imidazole and cyanide. In addition, the Em values showed pH-dependence, exhibiting a sigmoidal response whose pKa value was calculated at 6.9 likely associated to a sixth heme ligand. In presence of CO and NO, the spectroelectrochemical curves showed hysteresis due to the complete dissociation of the ligands in the oxidized state. Oxidation potentials of 385 and 130 mV vs NHE were determined for CO-HGbI(FeII) and NO-HGbI(FeII) species, respectively. Altogether, these results suggest HGbI protein is likely not involved in the storage nor in the transport of oxygen in the Methylacidiphilum infernorum microorganism. Nevertheless, it is implied the physiological function of HGbI might be related to redox-based processes, which remains to be further elucidated.
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.
Extremophiles are organisms capable of adjust, survive or thrive in hostile habitats that were previously thought to be adverse or lethal for life. Chile gathers a wide range of extreme environments: ...salars, geothermal springs, and geysers located at Altiplano and Atacama Desert, salars and cold mountains in Central Chile, and ice fields, cold lakes and fjords, and geothermal sites in Patagonia and Antarctica. The aims of this review are to describe extremophiles that inhabit main extreme biotopes in Chile, and their molecular and physiological capabilities that may be advantageous for bioremediation processes. After briefly describing the main ecological niches of extremophiles along Chilean territory, this review is focused on the microbial diversity and composition of these biotopes microbiomes. Extremophiles have been isolated in diverse zones in Chile that possess extreme conditions such as Altiplano, Atacama Desert, Central Chile, Patagonia, and Antarctica. Interesting extremophiles from Chile with potential biotechnological applications include thermophiles (e.g.,
from Tatio Geyser), acidophiles (e.g.,
from Atacama Desert and Central Chile copper ores), halophiles (e.g.,
sp. Asc-3 from Altiplano,
sp. HKF-8 from Patagonia), alkaliphiles (
sp. SH31 from Altiplano), xerotolerant bacteria (
from Atacama Desert), UV- and Gamma-resistant bacteria (
from Atacama Desert) and psychrophiles (e.g.,
ATH-43 from Antarctica). The molecular and physiological properties of diverse extremophiles from Chile and their application in bioremediation or waste treatments are further discussed. Interestingly, the remarkable adaptative capabilities of extremophiles convert them into an attractive source of catalysts for bioremediation and industrial processes.
Marinobacter
spp. are cosmopolitan in saline environments, displaying a diverse set of metabolisms that allow them to competitively occupy these environments, some of which can be extreme in both ...salinity and temperature. Here, we introduce a distinct cluster of
Marinobacter
genomes, composed of novel isolates and
in silico
assembled genomes obtained from subzero, hypersaline cryopeg brines, relic seawater-derived liquid habitats within permafrost sampled near Utqiaġvik, Alaska. Using these new genomes and 45 representative publicly available genomes of
Marinobacter
spp. from other settings, we assembled a pangenome to examine how the new extremophile members fit evolutionarily and ecologically, based on genetic potential and environmental source. This first genus-wide genomic analysis revealed that
Marinobacter
spp. in general encode metabolic pathways that are thermodynamically favored at low temperature, cover a broad range of organic compounds, and optimize protein usage, e.g., the Entner–Doudoroff pathway, the glyoxylate shunt, and amino acid metabolism. The new isolates contributed to a distinct clade of subzero brine-dwelling
Marinobacter
spp. that diverged genotypically and phylogenetically from all other
Marinobacter
members. The subzero brine clade displays genomic characteristics that may explain competitive adaptations to the extreme environments they inhabit, including more abundant membrane transport systems (e.g., for organic substrates, compatible solutes, and ions) and stress-induced transcriptional regulatory mechanisms (e.g., for cold and salt stress) than in the other
Marinobacter
clades. We also identified more abundant signatures of potential horizontal transfer of genes involved in transcription, the mobilome, and a variety of metabolite exchange systems, which led to considering the importance of this evolutionary mechanism in an extreme environment where adaptation
via
vertical evolution is physiologically rate limited. Assessing these new extremophile genomes in a pangenomic context has provided a unique view into the ecological and evolutionary history of the genus
Marinobacter
, particularly with regard to its remarkable diversity and its opportunism in extremely cold and saline environments.
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.
Various microorganisms thrive under extreme environments, like hot springs, hydrothermal vents, deep marine ecosystems, hyperacid lakes, acid mine drainage, high UV exposure, and more. To survive ...against the deleterious effect of these extreme circumstances, they form a network of biofilm where exopolysaccharides (EPSs) comprise a substantial part. The EPSs are often polyanionic due to different functional groups in their structural backbone, including uronic acids, sulfated units, and phosphate groups. Altogether, these chemical groups provide EPSs with a negative charge allowing them to (a) act as ligands toward dissolved cations as well as trace, and toxic metals; (b) be tolerant to the presence of salts, surfactants, and alpha-hydroxyl acids; and (c) interface the solubilization of hydrocarbons. Owing to their unique structural and functional characteristics, EPSs are anticipated to be utilized industrially to remediation of metals, crude oil, and hydrocarbons from contaminated wastewaters, mines, and oil spills. The biotechnological advantages of extremophilic EPSs are more diverse than traditional biopolymers. The present review aims at discussing the mechanisms and strategies for using EPSs from extremophiles in industries and environment bioremediation. Additionally, the potential of EPSs as fascinating biomaterials to mediate biogenic nanoparticles synthesis and treat multicomponent water contaminants is discussed.
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