Beneficial Effect of the New Leptodophora sp. Strain on Development of Blueberry Microclones in the Process of Their Adaptation

The paper searches for new solutions for the development of highbush blueberry orchards (Vaccinium corymbosum L. (1753)) in Western Siberia. All species of the genus Vaccinium display special symbiotic mycorrhizal associations with root systems-ericoid mycorrhiza, which essentially enhances the formation of adventitious and lateral roots. For the first time, we obtained pure cultures of micromycetes associated with the roots of wild species of the family Ericaceae in the Tomsk region, Russia. With regard to the data of molecular genetic analysis of the ITS region sequence, we selected the BR2-1 isolate based on its morphophysiological traits, which was assigned to the genus Leptodophora. Representatives of this genus typically enter into symbiotic relationships with heathers to form ericoid mycorrhizae. We studied the effect of strain BR2-1 on the development of microclones of the highbush blueberry var. Nord blue during their in vitro adaptation and showed its beneficial effect on growth and shoot formation in young plants. Experiments performed using submerged and solid-state methods showed that the most optimal method for commercial production of BR2-1 is cultivation on grain sterilized by boiling, followed by spore washing.

Active Sulfate-Reducing Bacterial Community in the Camel Gut

The diversity and activity of sulfate-reducing bacteria (SRB) in the camel gut remains largely unexplored. An abundant SRB community has been previously revealed in the feces of Bactrian camels (Camelus bactrianus). This study aims to combine the 16S rRNA gene profiling, sulfate reduction rate (SRR) measurement with a radioactive tracer, and targeted cultivation to shed light on SRB activity in the camel gut. Fresh feces of 55 domestic Bactrian camels grazing freely on semi-arid mountain pastures in the Kosh-Agach district of the Russian Altai area were analyzed. Feces were sampled in early winter at an ambient temperature of -15 °C, which prevented possible contamination. SRR values measured with a radioactive tracer in feces were relatively high and ranged from 0.018 to 0.168 nmol S cm^-3 day^-1. The 16S rRNA gene profiles revealed the presence of Gram-negative Desulfovibrionaceae and spore-forming Desulfotomaculaceae. Targeted isolation allowed us to obtain four pure culture isolates belonging to Desulfovibrio and Desulforamulus. An active SRB community may affect the iron and copper availability in the camel intestine due to metal ions precipitation in the form of sparingly soluble sulfides. The copper-iron sulfide, chalcopyrite (CuFeS₂), was detected by X-ray diffraction in 36 out of 55 analyzed camel feces. In semi-arid areas, gypsum, like other evaporite sulfates, can be used as a solid-phase electron acceptor for sulfate reduction in the camel gastrointestinal tract.

Distribution Patterns of Antibiotic Resistance Genes and Their Bacterial Hosts in a Manure Lagoon of a Large-Scale Swine Finishing Facility

The spread of antibiotic resistance genes (ARGs) that are present in livestock manures, which are discharged into the environment, is a severe threat to human and animal health. Here, we used 16S rRNA gene profiling and metagenomic analysis to characterize microbial community composition and antibiotic resistance in a manure storage lagoon from a large-scale swine finishing facility. Manure samples were collected at intervals of two years. Both the prokaryotic community and the resistome were dominated by the Firmicutes, Proteobacteria and Bacteroidota. Metagenomic analysis of two samples revealed 726 and 641 ARGs classified into 59 and 46 AMR gene families. Besides multidrug efflux pumps, the predominating ARGs potentially encoded resistance to tetracyclines, macrolide-lincosamide-streptogramin, aminoglycosides, peptide antibiotics, rifamycin, chloramphenicol, and beta-lactams. Genes from all predominant AMR gene families were found in both samples indicating overall long-term stability of the resistome. Antibiotic efflux pumps were the primary type of ARGs in the Proteobacteria, while antibiotic target alteration or protection was the main mechanism of resistance in the Firmicutes, Actinobacteriota and Bacteroidota. Metagenome-assembled genomes (MAG) of four multidrug-resistant strains were assembled. The first MAG, assigned to Escherichia flexneri, contained 46 ARGs, including multidrug efflux pumps, modified porins, beta-lactamases, and genes conferring resistance to peptide antibiotics. The second MAG, assigned to the family Alcaligenaceae, contained 18 ARGs encoding resistance to macrolide-lincosamide-streptogramin, tetracyclines, aminoglycosides and diaminopyrimidins. Two other MAGs representing the genera Atopostipes and Prevotella, contained four and seven ARGs, respectively. All these MAGs represented minor community members and accounted for less than 0.3% of the whole metagenome. Overall, a few lineages originated from the gut but relatively rare in the manure storage lagoon, are the main source of ARGs and some of them carry multiple resistance determinants.

Isolation, Characterization, and Metal Response of Novel, Acid-Tolerant Penicillium spp. from Extremely Metal-Rich Waters at a Mining Site in Transbaikal (Siberia, Russia)

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 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 Ni-sulfate (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.

The complete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C

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 26,725 bp. 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.

Effect of Tree Species on Enzyme Secretion by the Shiitake Medicinal Mushroom, Lentinus edodes (Agaricomycetes)

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.

Increased mycelial biomass production by Lentinula edodes intermittently illuminated by green light emitting diodes

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.