Search

Hydrogen is a key energy-yielding substrate for microbial processes in the deep biosphere. Fracture water of a deep gold mine in South Africa is a well-known example of the ecosystem based on a hydrogenotrophic sulfate reducer, “Candidatus Desulforudis audaxviator.” The present work reports the cultivation and pure culture isolation of a novel obligate chemolithotroph reducing sulfate during growth on hydrogen or formate. Phylogenetic analysis of the 16S rRNA gene of the strain Tu-874 showed its clusterization with its closest cultured relative, “Candidatus Desulforudis audaxviator.” However, the low 16S rRNA sequence similarity of 88.95% indicates that the organism represents a new taxonomic group above the species level.

Sulfate-reducing bacteria (SRB) of the genus Desulfovibrio are one of the groups occurring in elevated numbers in the gut of children with autistic spectrum disorders (ASD). Until now, high abundance of Desulfovibrio in individuals with RAS has been shown only by molecular methods. No cultured forms have been isolated from the gastrointestinal tract of autists. A conceivable mechanisms of SRB effect is conversion of iron into biologically unavailable forms of sulfides, causing its deficiency in the organism. In this study we isolated two Desulfovibrio strains from feces of the children with diagnosed ASD. In experiments Desulfovibrio desulfuricans AY5 formed crystalline iron sulfides, greigite and pyrite, containing iron in a biologically unavailable form.

Micromycetes can precipitate metals in the form of insoluble oxalates, thus participating in metal removal from geochemical cycling and in secondary mineral formation. Metal precipitation has a practical application for bioleaching and bioremediation. Micromycetes from the genus Aspergillus are used as model organisms to study metal precipitation. All known biomineralization processes carried out by micromycetes described so far involved mesophilic organisms. Thermophilic eukaryotes may be advantageous for biotechnologies. This study reports the isolation of thermophilic/thermotolerant Aspergillus spp. from burning wastes of coal mining in Kuzbass and their participation in formation of insoluble copper oxalate, moolooite. Copper-enriched extracellular vesicles formed in the process may act as nucleation sites for the moolooite crystals formation.

Spore-forming sulfate-reducing bacteria, previously assigned to the genus Desulfotomaculum, are typical inhabitants of thermal groundwater biotopes (Aüllo et al., 2013; Frank et al., 2016). Due to their ability to form spores, to grow autotrophically, and to survive high temperatures, this group is a successful colonizer of groundwaters. Revision of the genus Desulfotomaculum resulted in description of four new genera, Desulfallas, Desulfofundulus, Desulfofarcimen, and Desulfohalotomaculum (Watanabe et al., 2018)

Plant biopesticides can be an alternative to the use of synthetic chemicals in agriculture. Knotweeds (Reynoutria. japonica and Reynoutria. sachalinensis) are known as producers of biologically active substances including allelochemicals with fungicide properties. In this study we investigated the effect of the R. japonica Houtt. extract against the pure culture of Fusarium sp. ZhI isolated from leaves of strawberries infected by mycosis. The inhibitory effect of the R. japonica dealcoholized ethanol extract against the phytopathogenic fungus was shown at a concentration of 5%. The addition of the extract at this concentration to the growth medium reliably reduced the diameter of the Fusarium sp. ZhI colonies and its growth rate.

The work is focused on the selection of an appropriate substrate for solid-state fermentation using B. bassiana with the aim of a biopesticide production. The highest number of conidia was yielded during cultivation on polished rice moistened with water in a ratio of 1:1.5 and 1:2.

The productivity of three Trichoderma spp. on different media was compared. The tolerance to salinization and inoculation temperature in the process of solid-state cultivation were determined.

The specific growth rates of Pleurotus ostreatus, Pleurotus eryngii and Ganoderma lucidum were determined on different culture media. Based on the data obtained, the optimal substrates were selected for the further production of artificial leather and construction biomaterials using fungal mycelium.

The role of fungi in metal cycling in acidic environments has been little explored to date. In this study, two acid-tolerant and metal-resistant Penicillium isolates, strains ShG4B and ShG4C, were isolated from a mine site in the Transbaikal area of Siberia (Russia). Waters at the mine site were characterized by extremely high metal concentrations: up to 18 g l−1 Fe and >2 g l−1 each of Cu, Zn, Al, and As. Both isolates were identified as Penicillium spp. by phylogenetic analyses and they grew well in Czapek medium acidified to pH 2.5. Resistance to Cu, Cd, Ni, Co, and arsenate was in\ud the range of 1–10 g l−1. Further experiments with Penicillium strain ShG4C demonstrated that growth in Cu-containing media was accompanied by the precipitation of Cu-oxalate (moolooite) and the formation of extracellular vesicles enriched in Cu on the mycelia. Vesicles were greatly reduced in size in Cd-containing media and were not formed in the presence of Ni or Co. Cd-oxalate was detected as a crystalline solid phase in Cd-exposed mycelia. Hydrated Nisulfate (retgersite) and Co-sulfate (bieberite) were detected in mycelia grown in the presence of Ni and Co, respectively. The results demonstrated that acid-tolerant and metal-resistant Penicillium constitute a component in extremophilic microbiomes, contributing to organic matter breakdown and formation of secondary solid phases at pH ranges found in acid rock drainage.

Complete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C, isolated from oxidized sediments of an abandoned polymetallic mine site, has been sequenced using high-throughput sequencing approach. The mitochondrial genome represents a circular DNA molecule with size of 26,725bp. It encodes a usual set of mitochondrial genes, including 15 protein coding genes, large and small ribosomal RNAs and 27 tRNA genes. All genes are located on H-strand DNA and transcribed in one direction. Taxonomic analysis based on concatenated sequences of mitochondrial proteins confirmed taxonomic position of this fungus within the genus Penicillium. The sequence of the complete mitochondrial genome of Penicillium ShG4C was deposited in DBBJ/EMBL/GenBank under accession number KX931017.

We compared cold and hot wood extracts of 3 endemic Siberian trees-namely, Prunus padus (bird cherry), Populus tremula (aspen), and Betula sp. (birch)-on biomass production and laccase and peroxidase secretion in submerged cultures by the medicinal mushroom Lentinus edodes. Of the conditions tested, only hot Prunus extracts stimulated biomass production, whereas all extracts stimulated laccase and peroxidase secretion, albeit to different extents. A large, differential stimulation of manganese peroxidase was observed by hot Prunus extracts. The results highlight important differences between tree species in the stimulation of biomass and enzyme production by L. edodes and point to potentially interesting stimulatory factors present in hot Prunus extracts. These findings are of relevance in the use of L. edodes for medicinal or biotechnological applications.

Fungi possess a range of light receptors to regulate metabolism and differentiation. To study the effect of light on Lentinula edodes (the shiitake mushroom), mycelial cultures were exposed to blue, green, and red fluorescent lights and light-emitting diodes, as well as green laser light. Biomass production, morphology, and pigment production were evaluated. Exposure to green light at intervals of 1 min/d at 0.4 W/m(2) stimulated biomass production by 50-100 %, depending on the light source. Light intensities in excess of 1.8 W/m(2) or illumination longer than 30 min/d did not affect biomass production. Carotenoid production and morphology remained unaltered during increased biomass production. These observations provide a cornerstone to the study of photoreception by this important fungus.