Alina V. Teplyuk

Bio: Alina V. Teplyuk is an academic researcher from Immanuel Kant Baltic Federal University. The author has an hindex of 1, co-authored 1 publications receiving 12 citations.

Genomic Insights Into Energy Metabolism of Carboxydocella thermautotrophica Coupling Hydrogenogenic CO Oxidation With the Reduction of Fe(III) Minerals.

Abstract: The genus Carboxydocella forms a deeply branching family in the class Clostridia and is currently represented by three physiologically diverse species of thermophilic prokaryotes. The type strain of the type species, Carboxydocella thermautotrophica 41T, is an obligate chemolithoautotroph growing exclusively by hydrogenogenic CO oxidation. Another strain, isolated from a hot spring at Uzon caldera, Kamchatka in the course of this work, is capable of coupling carboxydotrophy and dissimilatory reduction of Fe(III) from oxic and phyllosilicate minerals. The processes of carboxydotrophy and Fe(III) reduction appeared to be interdependent in this strain. The genomes of both isolates were sequenced, assembled into single chromosome sequences (for strain 41T a plasmid sequence was also assembled) and analyzed. Genome analysis revealed that each of the two strains possessed six genes encoding diverse Ni,Fe-containing CO dehydrogenases (maximum reported in complete prokaryotic genomes), indicating crucial role of carbon monoxide in C. thermautotrophica metabolism. Both strains possessed a set of 30 multiheme c-type cytochromes, but only the newly isolated Fe-reducing strain 019 had one extra gene of a 17-heme cytochrome, which is proposed to represent a novel determinant of dissimilatory iron reduction in prokaryotes. Mossbauer studies revealed that strain 019 induced reductive transformation of the abundant ferric/ferrous-mica mineral glauconite to siderite during carboxydotrophic growth. Reconstruction of the C. thermautotrophica strains energy metabolism is the first comprehensive genome analysis of a representative of the deep phylogenetic branch Clostridia Incertae Sedis, family V. Our data provide insights into energy metabolism of C. thermautotrophica with an emphasis on its ecological implications.

Life on the fringe: microbial adaptation to growth on carbon monoxide.

Abstract: Microbial adaptation to extreme conditions takes many forms, including specialized metabolism which may be crucial to survival in adverse conditions. Here, we analyze the diversity and environmental importance of systems allowing microbial carbon monoxide (CO) metabolism. CO is a toxic gas that can poison most organisms because of its tight binding to metalloproteins. Microbial CO uptake was first noted by Kluyver and Schnellen in 1947, and since then many microbes using CO via oxidation have emerged. Many strains use molecular oxygen as the electron acceptor for aerobic oxidation of CO using Mo-containing CO oxidoreductase enzymes named CO dehydrogenase. Anaerobic carboxydotrophs oxidize CO using CooS enzymes that contain Ni/Fe catalytic centers and are unrelated to CO dehydrogenase. Though rare on Earth in free form, CO is an important intermediate compound in anaerobic carbon cycling, as it can be coupled to acetogenesis, methanogenesis, hydrogenogenesis, and metal reduction. Many microbial species—both bacteria and archaea—have been shown to use CO to conserve energy or fix cell carbon or both. Microbial CO formation is also very common. Carboxydotrophs thus glean energy and fix carbon from a “metabolic leftover” that is not consumed by, and is toxic to, most microorganisms. Surprisingly, many species are able to thrive under culture headspaces sometimes exceeding 1 atmosphere of CO. It appears that carboxydotrophs are adapted to provide a metabolic “currency exchange” system in microbial communities in which CO arising either abiotically or biogenically is converted to CO 2 and H 2 that feed major metabolic pathways for energy conservation or carbon fixation. Solventogenic CO metabolism has been exploited to construct very large gas fermentation plants converting CO-rich industrial flue emissions into biofuels and chemical feedstocks, creating renewable energy while mitigating global warming. The use of thermostable CO dehydrogenase enzymes to construct sensitive CO gas sensors is also in progress.

Anaerobic and hydrogenogenic carbon monoxide-oxidizing prokaryotes: Versatile microbial conversion of a toxic gas into an available energy.

Abstract: Carbon monoxide (CO) is a gas that is toxic to various organisms including humans and even microbes; however, it has low redox potential, which can fuel certain microbes, namely, CO oxidizers. Hydrogenogenic CO oxidizers utilize an energy conservation system via a CO dehydrogenase/energy-converting hydrogenase complex to produce hydrogen gas, a zero emission fuel, by CO oxidation coupled with proton reduction. Biochemical and molecular biological studies using a few model organisms have revealed their enzymatic reactions and transcriptional response mechanisms using CO. Biotechnological studies for CO-dependent hydrogen production have also been carried out with these model organisms. In this chapter, we review recent advances in the studies of these microbes, which reveal their unique and versatile metabolic profiles and provides future perspectives on ecological roles and biotechnological applications. Over the past decade, the number of isolates has doubled (37 isolates in 5 phyla, 20 genera, and 32 species). Some of the recently isolated ones show broad specificity to electron acceptors. Moreover, accumulating genomic information predicts their unique physiologies and reveals their phylogenomic relationships with novel potential hydrogenogenic CO oxidizers. Combined with genomic database surveys, a molecular ecological study has unveiled the wide distribution and low abundance of these microbes. Finally, recent biotechnological applications of hydrogenogenic CO oxidizers have been achieved via diverse approaches (e.g., metabolic engineering and co-cultivation), and the identification of thermophilic facultative anaerobic CO oxidizers will promote industrial applications as oxygen-tolerant biocatalysts for efficient hydrogen production by genomic engineering.

Diversity and distribution of thermophilic hydrogenogenic carboxydotrophs revealed by microbial community analysis in sediments from multiple hydrothermal environments in Japan.

Abstract: In hydrothermal environments, carbon monoxide (CO) utilisation by thermophilic hydrogenogenic carboxydotrophs may play an important role in microbial ecology by reducing toxic levels of CO and providing H2 for fuelling microbial communities. We evaluated thermophilic hydrogenogenic carboxydotrophs by microbial community analysis. First, we analysed the correlation between carbon monoxide dehydrogenase (CODH)–energy-converting hydrogenase (ECH) gene cluster and taxonomic affiliation by surveying an increasing genomic database. We identified 71 genome-encoded CODH–ECH gene clusters, including 46 whose owners were not reported as hydrogenogenic carboxydotrophs. We identified 13 phylotypes showing > 98.7% identity with these taxa as potential hydrogenogenic carboxydotrophs in hot springs. Of these, Firmicutes phylotypes such as Parageobacillus, Carboxydocella, Caldanaerobacter, and Carboxydothermus were found in different environmental conditions and distinct microbial communities. The relative abundance of the potential thermophilic hydrogenogenic carboxydotrophs was low. Most of them did not show any symbiotic networks with other microbes, implying that their metabolic activities might be low.

Novel Extracellular Electron Transfer Channels in a Gram-Positive Thermophilic Bacterium.

Abstract: Biogenic transformation of Fe minerals, associated with extracellular electron transfer (EET), allows microorganisms to exploit high-potential refractory electron acceptors for energy generation. EET-capable thermophiles are dominated by hyperthermophilic archaea and Gram-positive bacteria. Information on their EET pathways is sparse. Here, we describe EET channels in the thermophilic Gram-positive bacterium Carboxydothermus ferrireducens that drive exoelectrogenesis and rapid conversion of amorphous mineral ferrihydrite to large magnetite crystals. Microscopic studies indicated biocontrolled formation of unusual formicary-like ultrastructure of the magnetite crystals and revealed active colonization of anodes in bioelectrochemical systems (BESs) by C. ferrireducens. The internal structure of micron-scale biogenic magnetite crystals is reported for the first time. Genome analysis and expression profiling revealed three constitutive c-type multiheme cytochromes involved in electron exchange with ferrihydrite or an anode, sharing insignificant homology with previously described EET-related cytochromes thus representing novel determinants of EET. Our studies identify these cytochromes as extracellular and reveal potentially novel mechanisms of cell-to-mineral interactions in thermal environments.