sp. nov., a Thermophilic, Obligately Chemolithoautotrophic, Sulfur-Oxidizing Bacterium from a Hot Spring and Proposal of fam. nov.

An aerobic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium, strain AK1, was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka, Russia. The cells of the new isolate were Gram-negative motile rods with a single polar flagellum. Strain AK1 grew at 37-55 °C (optimum 50 °C) with 0-1.

Thermodesulfovibrio autotrophicus sp. nov., the first autotrophic representative of the widespread sulfate-reducing genus Thermodesulfovibrio, and Thermodesulfovibrio obliviosus sp. nov. that has lost this ability.

Representatives of the genus Thermodesulfovibrio are widespread thermophilic sulfate-reducing bacteria. The genus currently includes five species with validly published names. Two new Thermodesulfovibrio strains, 3907-1M  and 3462-1, were isolated with molecular hydrogen as an electron donor, sulfate as an electron acceptor and acetate as the carbon source from hot springs of Kunashir Island and Kamchatka Peninsula.

A Novel Species of the Genus Thermanaerothrix Isolated from a Kamchatka Hot Spring Possesses Hydrolytic Capabilities.

Hot springs are inhabited by specific microbial communities which are reservoirs of novel taxa. In this work strain 4228-RoL was isolated from the Solnechny hot spring, Uzon Caldera, Kamchatka. Cells of the strain 4228-RoL were Gram-negative rods forming multicellular filaments.

Ignisphaera cupida sp. nov., a hyperthermophilic hydrolytic archaeon from a hot spring of Uzon (Kamchatka), and emended description of the genus Ignisphaera.

A novel strictly anaerobic hyperthermophilic archaeon, strain 4213-co, was isolated from a terrestrial hot spring in the Uzon Caldera, Kamchatka (Russian Federation). Coccoid cells were present singly, in pairs, or aggregates, and occasionally were motile. The strain grew at 75-100 °C and within a pH range of 5.

Rosettibacter primus gen. nov., sp. nov., and Rosettibacter firmus sp. nov., facultatively anaerobic moderately thermophilic bacteria of the class Ignavibacteria from hot springs of North Ossetia.

A novel facultatively anaerobic moderately thermophilic bacteria, strains 4137-Me and 4148-Me, were isolated from hot springs of Karmadon and Ursdon, respectively (North Ossetia, Russian Federation). Gram-negative, motile rods were present singly, in pairs, rosettes, and aggregates, or formed biofilms. Both strains grew optimally at 50-55 °C, pH 7.

Natronosalvus hydrolyticus sp. nov., a beta-1,3-glucan utilizing natronoarchaeon from hypersaline soda lakes.

Use of curldlan, an insoluble β-1,3-glucan, as an enrichment substrate under aerobic conditions resulted in the selection from hypersaline soda lakes of a single natronarchaeon, strain AArc-curdl1. This organism is an obligately aerobic saccharolytic, possessing a poorly explored (in Archaea) potential to utilize beta-1-3 glucans, being only a second example of a haloarchaeon with this ability known in pure culture. The main phenotypic property of the isolate is the ability to grow with insoluble β-1,3-backboned glucans, i.

gen. nov., sp. nov., beta-1,4-mannan utilizing natronoarchaea from hypersaline soda lakes.

Beta-mannans are insoluble plant polysaccharides with beta-1,4-linked mannose as the backbone. We used three forms of this polysaccharide, namely, pure mannan, glucomannan, and galactomannan, to enrich haloarchaea, which have the ability to utilize mannans for growth. Four mannan-utilizing strains obtained in pure cultures were closely related to each other on the level of the same species.

Metagenomic Insights into the Taxonomic and Functional Features of Traditional Fermented Milk Products from Russia.

Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time.

Halapricum hydrolyticum sp. nov., a beta-1,3-glucan utilizing haloarchaeon from hypersaline lakes.

Two strains of neutrophilic haloaloarchaea were selectively enriched from hypersaline lakes in southwestern Siberia using β-1,3-glucans as a substrate. The strains were nearly identical in their phenotypes and according to phylogenomic analysis, and represent a distant novel species group in the genus Halapricum of the family Haloarculaceae. The main phenotypic property of the novel isolates is the ability to hydrolyze and grow with the polysaccharides curdlan and pachyman.

Cellulose metabolism in halo(natrono)archaea: a comparative genomics study.

Extremely halophilic archaea are one of the principal microbial community components in hypersaline environments. The majority of cultivated haloarchaea are aerobic heterotrophs using peptides or simple sugars as carbon and energy sources. At the same time, a number of novel metabolic capacities of these extremophiles were discovered recently among which is a capability of growing on insoluble polysaccharides such as cellulose and chitin.

Fontisphaera persica gen. nov., sp. nov., a thermophilic hydrolytic bacterium from a hot spring of Baikal lake region, and proposal of Fontisphaeraceae fam. nov., and Limisphaeraceae fam. nov. within the Limisphaerales ord. nov. (Verrucomicrobiota).

A novel facultatively anaerobic moderately thermophilic bacterium, strain B-154 , was isolated from a terrestrial hot spring in the Baikal lake region (Russian Federation). Gram-negative, motile, spherical cells were present singly, in pairs, or aggregates, and reproduced by binary fission. The strain grew at 30-57 °C and within a pH range of 5.

Obligate autotrophy at the thermodynamic limit of life in a new acetogenic bacterium.

One of the important current issues of bioenergetics is the establishment of the thermodynamic limits of life. There is still no final understanding of what is the minimum value of the energy yield of a reaction that is sufficient to be used by an organism (the so-called "biological quantum of energy"). A reasonable model for determination of the minimal energy yield would be microorganisms capable of living on low-energy substrates, such as acetogenic prokaryotes.

Draft Genome Sequence of sp. Strain 4228-Ro, a Thermophilic Bacterium Isolated from a Kamchatka Hot Spring.

The genome of sp. strain 4228-Ro, an aerobic thermophilic bacterium isolated from a Kamchatka hot spring, was sequenced and analyzed. The genome assembly comprises 13 contigs with a total length of 3,068,448 bp.

Draft Genome Sequence of Lactococcus lactis Strain 12-16-PSH, Isolated from Prostokvasha from the Arkhangelsk Region of Russia.

A draft genome sequence of Lactococcus lactis strain 12-16-PSH, which was isolated from prostokvasha, is reported. The genome assembly of strain 12-16-PSH contained 63 contigs, with a total length of 2,468,647 bp. A total of 2,421 protein-coding genes were predicted, among which 6 encoded bacteriocins while 15 encoded glycosyl transferases, presumably involved in exopolysaccharide biosynthesis.

Draft Genome Sequence of sp. Strain 3827-6, a Hyperthermophilic Crenarchaeon, Isolated from a Kamchatka Hot Spring.

The genome of sp. strain 3827-6, a facultative autotrophic hyperthermophilic archaeon isolated from a Kamchatka hot spring, was sequenced and analyzed. Genome analysis predicted the dicarboxylate/4-hydroxybutyrate cycle and a [NiFe]-hydrogenase, as well as the tricarboxylic acid cycle, altogether determining the possibility of both autotrophic and heterotrophic growth of this strain.

Selective enrichment on a wide polysaccharide spectrum allowed isolation of novel metabolic and taxonomic groups of haloarchaea from hypersaline lakes.

Extremely halophilic archaea (haloarchaea) of the class is a dominant group of aerobic heterotrophic prokaryotic communities in salt-saturated habitats, such as salt lakes and solar salterns. Most of the pure cultures of haloarchaea were enriched, isolated, and cultivated on rich soluble substrates such as amino acids, peptides or simple sugars. So far, the evidences on the capability of haloarchaea to use different polysaccharides as growth substrates remained scarce.

Taxonomic proposal for a deep branching bacterial phylogenetic lineage: transfer of the family Thermodesulfobiaceae to Thermodesulfobiales ord. nov., Thermodesulfobiia classis nov. and Thermodesulfobiota phyl. nov.

The family Thermodesulfobiaceae, comprising one genus Thermodesulfobium with two validly published species, is currently assigned to order Thermoanaerobacterales within the class Clostridia of the phylum Bacillota. At the same time, the very first 16S rRNA gene sequence-based phylogenetic studies of representatives of the genus pointed out great differences between Thermodesulfobium and other members of the phylum Bacillota. Subsequent studies of new Thermodesulfobium representatives supported deep phylogenetic branching of this lineage within bacterial tree, implying that it represents a novel phylum.

Microbial Communities of Artisanal Fermented Milk Products from Russia.

Fermented milk products (FMPs) have numerous health properties, making them an important part of our nutrient budget. Based on traditions, history and geography, there are different preferences and recipes for FMP preparation in distinct regions of the world and Russia in particular. A number of dairy products, both widely occurring and region-specific, were sampled in the households and local markets of the Caucasus republics, Buryatia, Altai, and the Far East and European regions of Russia.

Fontivita pretiosa gen. nov., sp. nov., a thermophilic planctomycete of the order Tepidisphaerales from a hot spring of Baikal lake region.

A novel facultatively anaerobic moderately thermophilic bacterium, strain B-254, was isolated from a terrestrial hot spring near the town of Goryachinsk in the Baikal lake region (Russian Federation). Motile spherical cells of the strain were present as single cocci, in pairs, or aggregates. The cells had a Gram negative cell wall and reproduced by binary fission.

Natronocalculus amylovorans gen. nov., sp. nov., and Natranaeroarchaeum aerophilus sp. nov., dominant culturable amylolytic natronoarchaea from hypersaline soda lakes in southwestern Siberia.

Several pure cultures of alkaliphilic haloaloarchaea were enriched and isolated from hypersaline soda lakes in southwestern Siberia using amylopectin and fructans as substrates. Phylogenomic analysis placed the isolates into two distinct groups within the class Halobacteria. Four isolates forming group 1 were closely related to a recently described Natranaeroarchaeum sulfidigenes and the other three strains forming group 2 represent a novel genus-level phylogenetic lineage.

Natronosporangium hydrolyticum gen. nov., sp. nov., a haloalkaliphilic polyhydrolytic actinobacterium from a soda solonchak soil in Central Asia.

During a cultural diversity survey on hydrolytic bacteria in saline alkaline soils, a hydrolytic actinobacterium strain ACPA39 was enriched and isolated in pure culture from a soda solonchak soil in southwestern Siberia. It forms a substrate mycelium with rod-shaped sporangia containing 1-3 exospores. The isolate is obligately alkaliphilic, growing at pH 7.

Activity-Based Protein Profiling for the Identification of Novel Carbohydrate-Active Enzymes Involved in Xylan Degradation in the Hyperthermophilic Euryarchaeon sp. Strain 2319x1E.

Activity-based protein profiling (ABPP) has so far scarcely been applied in Archaea in general and, especially, in extremophilic organisms. We herein isolated a novel strain designated sp. strain 2319x1E derived from the same enrichment culture as the recently reported sp.

Culture-Independent Survey of Thermophilic Microbial Communities of the North Caucasus.

The Greater Caucasus is a part of seismically active Alpine-Himalayan orogenic belt and has been a center of significant volcanic activity during the Quaternary period. That led to the formation of the number of hydrothermal habitats, including subterranean thermal aquifers and surface hot springs. However, there are only a limited number of scientific works reporting on the microbial communities of these habitats.

Novel hyperthermophilic crenarchaeon Infirmifilum lucidum gen. nov. sp. nov., reclassification of Thermofilum uzonense as Infirmifilum uzonense comb. nov. and assignment of the family Thermofilaceae to the order Thermofilales ord. nov.

A novel hyperthermophilic crenarchaeon, strain 3507LT, was isolated from a terrestrial hot spring near Tinguiririca volcano, Chile. Cells were non-motile thin, slightly curved filamentous rods. It grew at 73-93 °C and pH range of 5 to 7.