Multiple Euryhaline Lineages of Centrohelids (Haptista: Centroplasthelida) in Inland Saline Waters Revealed with Metabarcoding.

The diversity of centrohelids in inland saline waters was studied with metabarcoding for the first time. The fragment of V6-V7 regions of 18S rDNA was sequenced with newly designed primers. Obtained OTUs were identified with molecular phylogenetic analysis and comparison of the signatures in 39es9 hairpin of V7. The obtained data included some OTUs, which could be attributed to four described species, but the majority belonged to previously established or novel environmental clades. Along with some presumably marine/brackish clades and freshwater/low salinity (0-2 ppt) clades, seven presumable species demonstrating broad (from 1-2 up to 78 ppt) salinity tolerance were detected. A number of OTUs belonged to Raphidocystis contractilis, which is known from three independent findings in brackish habitats only. Thus, it was assumed that this species is stenohaline and specifically adapted to salinity 5-15 ppt. The high level of salinity tolerance was suggested for centrohelids before based on morphology, which was used to justify their cosmopolitan distribution. Later these views were criticized based on environmental sequencing, but the results of the current survey indicate, that at least some species are present at salinities from almost freshwater (1-2 ppt) to twice oceanic (78 ppt) and are presumably capable of overcoming oceanic salinity barriers for their distribution.

High-Throughput Sequencing of the 16S rRNA Gene as a Survey to Analyze the Microbiomes of Free-Living Ciliates Paramecium.

Ciliates are the largest group of ubiquitous aquatic bacterivorous protists, and many species are easily cultivated. However, only few studies reported prokaryotic communities naturally associated with ciliate cells. Herein, we analyzed the microbiome composition of several strains of Paramecium (Ciliophora) originating from different locations and belonging to two morpho-species by high-throughput sequencing (HTS) of the 16S rRNA gene. Possible reasons of HTS results bias were addressed comparing DNA libraries obtained using different primers and different number of ciliate cells. Microbiomes associated with ciliates and their environments were always significantly different by prokaryotic taxonomic composition and bacterial richness. There were also pronounced differences between Paramecium strains. Interestingly, potentially pathogenic bacteria were revealed in Paramecium microbiomes.

Oral microbiomes in children with asthma and dental caries.

OBJECTIVE: Recently, a significant association between dental caries and the severity of bronchial asthma in children has been revealed. This finding indicates a possible relationship between the oral microbiome and the pathogenesis of asthma. The purpose of our study was to estimate differences in the dental plaque microbiota of asthmatic children with and without dental caries by 16S rDNA sequencing. MATERIAL AND METHODS: Dental plaque samples were obtained with a spoon excavator from the occlusal surface of one deciduous tooth (the second mandibular left molar in caries-free children and the most affected tooth in caries-affected children). Total DNA was extracted from dental plaque. DNA libraries were analysed by 16S rRNA gene sequencing on the MiSeq (Illumina) platform. RESULTS: There were no significant differences in the composition of bacterial communities from both caries-affected and caries-free children with asthma. The "caries-enriched" genus was Veillonella (Veillonellaceae, Selenomonadales, Negativicutes). Relative abundance of Neisseria was significantly higher in caries-free children with asthma (p < 0.05). CONCLUSIONS: The most significant difference in compared bacterial communities was a higher relative abundance of Veillonella in caries-affected plaques that suggests its involvement in pathogenesis of caries. Potential respiratory pathogens are present in oral cavity of both caries-affected and caries-free asthmatic children.

Data on rumen and faeces microbiota profiles of Yakutian and Kalmyk cattle revealed by high-throughput sequencing of 16S rRNA gene amplicons.

It is known that the rumen microbiome directly or indirectly contributes to animal production, and may be a prospective target for mitigation of greenhouse gas emissions [1]. At the same time, feed types and components of diet can influence the composition of the rumen microbiome [2,3]. Fluctuations in the composition of the digestive tract microbiota can alter the development, health, and productivity of cattle [4]. Many studies of cattle microbiomes have focussed on the rumen microbiota, whereas the faecal microbiota has received less attention [5], [6], [7]. Therefore, the features of the faecal and the ruminal microbiomes in different cattle breeds are yet to be studied. Here, we provided 16S rRNA gene amplicon data of the ruminal and the faecal microbiomes from Yakutian and Kalmyk cattle living in the Republic of Sakha, Yakutia, Russia. Total DNA was extracted from 13 faecal and 13 ruminal samples, and DNA libraries were prepared and sequenced on an Illumina MiSeq platform. Paired-end raw reads were processed, and final operational taxonomic units (OTUs) were assigned to the respective prokaryotic taxa using the RDP (Ribosomal Database Project) database. Analysis of the microbiome composition at the phylum level revealed very similar faecal microbiota between the introduced Kalmyk breed and the indigenous Yakutian breed, whereas the ruminal microbiomes of these breeds differed substantially in terms of relative abundance of some prokaryotic phyla. We believe that the data obtained may provide new insights into the dynamics of the ruminal and the faecal microbiota of cattle as well as disclose breed-specific features of ruminal microbiomes. Besides, these data will contribute to our understanding of the ruminal microbiome structure and function, and might be useful for the management of cattle feeding and ruminal methane production.

Data on draft genome sequence of stenotrophomonas sp. SAM-B isolated from a mineral cold spring located in Tyva, southern Siberia.

Stenotrophomonas sp. SAM-B was isolated from Uzharlyg Mineral Cold Spring, Samagaltay Settlement, Republic of Tyva (Southern Siberia), Russian Federation. A whole genome sequencing of Stenotrophomonas sp. SAM-B was performed using an Illumina MiSeq platform. The resulting draft genome contains 4,253,956 bp with 66.48% GC-content and 71 contigs; the longest contig contains 968,648 bp, and the N50 has a length of 401,736 bp. The genome includes 3816 protein-coding genes, among which 23 are responsible for protein degradation, 65 are associated with stress response, and 31 are associated with virulence, disease, and defense, including beta-lactamase and resistance to fluoroquinolones. The genome data on the SAM-B strain provides fundamental knowledge that would allow a better understanding of the microorganisms inhabiting cold water environments. Moreover, the results of the genome annotation indicated that diverse metabolic pathways are encoded in the genome of the SAM-B strain and that it has biotechnological potential. The draft genome sequence of Stenotrophomonas sp. SAM-B has been deposited in DDBJ/ENA/GenBank under the accession number JABBXB000000000; the accession number of the genome sequence referred to in this paper is JABBXB010000000.

Complete Genome Sequence of Abscisic Acid-Metabolizing Rhizobacterium Rhodococcus sp. Strain P1Y.

Mechanisms of microbial catabolism of phytohormone abscisic acid (ABA) are still unknown. Here, we report the complete genome sequence of ABA-utilizing Rhodococcus sp. strain P1Y, isolated from the rice (Oryza sativa L.) rhizosphere. The sequence was obtained using an approach combining Oxford Nanopore Technologies MinION and Illumina MiSeq sequence data.