Identification of Epidemiological Traits by Analysis of SARS−CoV−2 Sequences

Severe acute respiratory syndrome coronavirus 2 (SARS−CoV−2) has caused the ongoing global COVID-19 pandemic that began in late December 2019. The rapid spread of SARS−CoV−2 is primarily due to person-to-person transmission. To understand the epidemiological traits of SARS−CoV−2 transmission, we conducted phylogenetic analysis on genome sequences from >54K SARS−CoV−2 cases obtained from two public databases. Hierarchical clustering analysis on geographic patterns in the resulting phylogenetic trees revealed a co-expansion tendency of the virus among neighboring countries with diverse sources and transmission routes for SARS−CoV−2. Pairwise sequence similarity analysis demonstrated that SARS−CoV−2 is transmitted locally and evolves during transmission. However, no significant differences were seen among SARS−CoV−2 genomes grouped by host age or sex. Here, our identified epidemiological traits provide information to better prevent transmission of SARS−CoV−2 and to facilitate the development of effective vaccines and therapeutics against the virus.

Single molecule, near full-length genome sequencing of dengue virus

Current methods for dengue virus (DENV) genome amplification, amplify parts of the genome in at least 5 overlapping segments and then combine the output to characterize a full genome. This process is laborious, costly and requires at least 10 primers per serotype, thus increasing the likelihood of PCR bias. We introduce an assay to amplify near full-length dengue virus genomes as intact molecules, sequence these amplicons with third generation “nanopore” technology without fragmenting and use the sequence data to differentiate within-host viral variants with a bioinformatics tool (Nano-Q). The new assay successfully generated near full-length amplicons from DENV serotypes 1, 2 and 3 samples which were sequenced with nanopore technology. Consensus DENV sequences generated by nanopore sequencing had over 99.5% pairwise sequence similarity to Illumina generated counterparts provided the coverage was > 100 with both platforms. Maximum likelihood phylogenetic trees generated from nanopore consensus sequences were able to reproduce the exact trees made from Illumina sequencing with a conservative 99% bootstrapping threshold (after 1000 replicates and 10% burn-in). Pairwise genetic distances of within host variants identified from the Nano-Q tool were less than that of between host variants, thus enabling the phylogenetic segregation of variants from the same host.

DeepSVM-fold: protein fold recognition by combining support vector machines and pairwise sequence similarity scores generated by deep learning networks

Protein fold recognition is critical for studying the structures and functions of proteins. The existing protein fold recognition approaches failed to efficiently calculate the pairwise sequence similarity scores of the proteins in the same fold sharing low sequence similarities. Furthermore, the existing feature vectorization strategies are not able to measure the global relationships among proteins from different protein folds. In this article, we proposed a new computational predictor called DeepSVM-fold for protein fold recognition by introducing a new feature vector based on the pairwise sequence similarity scores calculated from the fold-specific features extracted by deep learning networks. The feature vectors are then fed into a support vector machine to construct the predictor. Experimental results on the benchmark dataset (LE) show that DeepSVM-fold obviously outperforms all the other competing methods.

Tumebacillus lipolyticus sp. nov., isolated from river water

An aerobic, endospore-forming, alkali-tolerant, Gram-stain-positive, non-motile, rod-shaped bacterium, designated strain NIO-S10T, was isolated from a surface water sample collected from the Godavari River, Kapileswarapuram, India. Colonies on nutrient agar were circular, 3-4 mm in diameter, creamish and raised after incubation for 36 h at 37 °C. Growth occurred at 20–40 °C, at pH 6–9 and in the presence of 0–2 % (w/v) NaCl. Strain NIO-S10T was positive for oxidase, caseinase, DNase, gelatinase, lipase and urease activities, and negative for catalase, aesculinase, amylase and cellulase activities. The fatty acids were dominated by branched and saturated fatty acids, with a high abundance of iso-C15 : 0, anteiso-C15 : 0 and C18 : 0.The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid, and MK-7 was the major menaquinone. The DNA G+C content of strain NIO-S10T was 54.4 mol%. A blast sequence similarity search based on 16S rRNA gene sequences indicated that Tumebacillus ginsengisoli Gsoil 1105T was the nearest phylogenetic neighbour to strain NIO-S10T, with a pairwise sequence similarity of 94.9 %. Phylogenetic analysis showed that strain NIO-S10T was clustered with members of the genus Tumebacillus and together with members of the genus Effusibacillus. Based on phenotypic characteristics and phylogenetic inference, strain NIO-S10T represents a novel species of the genus Tumebacillus, for which the name Tumebacillus lipolyticus sp. nov. is proposed. The type strain is NIO-S10T ( = KCTC 32289T = MTCC 12483T).

Cavicella subterranea gen. nov., sp. nov., isolated from a deep mineral-water aquifer, and emended description of the species Perlucidibaca piscinae

One strain designated W2.09-231T was isolated from an aquifer through a 150-metre-deep borehole feeding a mineral-water bottling plant in Central Portugal. Based on 16S rRNA gene sequence analysis, the novel organism is most closely related to the species of the genera Perlucidibaca and Paraperlucidibaca, belonging to the family Moraxellaceae, with 16S rRNA gene pairwise sequence similarity of 94.5 and 93.1 %, respectively. The strain was not pigmented and formed Gram-stain-negative, non-motile, short rod-shaped cells. The organism was strictly aerobic, and oxidase- and catalase-positive. Strain W2.09-231T was organotrophic, but grew only on a very limited number of single carbon sources. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one major unknown phospholipid. Ubiquinone 12 (U-12) was the major respiratory quinone. The DNA G+C content of strain W2.09-231T was 62.0 mol%. Based on phylogenetic, physiological and biochemical characteristics, we describe a novel species of a novel genus represented by strain W2.09-231T ( = CECT 8582T = LMG 28332T) for which we propose the name Cavicella subterranea gen. nov., sp. nov. We also propose to emend the description of the species Perlucidibaca piscinae to reflect new results obtained in this study.

Marinobacter nitratireducens sp. nov., a halophilic and lipolytic bacterium isolated from coastal surface sea water

A novel Gram-stain-negative, rod-shaped, motile bacterium, designated strain AK21T, was isolated from coastal surface sea water at Visakhapatnam, India. The strain was positive for oxidase, catalase, lipase, l-proline arylamidase and tyrosine arylamidase activities. The predominant fatty acids were C12:0, C12:0 3-OH, C16:0, C16:1ω9c, C18:1ω9c and summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid, two unidentified phospholipids and one unidentified lipid. Q-10 was the predominant respiratory quinone. The DNA G+C content of the strain was 54.6 mol%. 16S rRNA gene sequence analysis indicated that strain AK21T was a member of the genus Marinobacter and was closely related to Marinobacter xestospongiae, with pairwise sequence similarity of 97.2 % to the type strain, with similarity to other members of the genus of 94.0–96.8 %. The mean DNA–DNA relatedness of strain AK21T with M. xestospongiae JCM 17469T was 34.5 %, and relatedness with Marinobacter mobilis JCM 15154T was 40.5 %. Phylogenetic analysis showed that strain AK21T clustered with the type strains of M. xestospongiae and M. mobilis at distances of 2.9 and 2.8 % (97.1 and 97.2 % similarity), respectively. Based on the phenotypic characteristics and on phylogenetic inference, it appears that strain AK21T represents a novel species of the genus Marinobacter, for which the name Marinobacter nitratireducens sp. nov. is proposed. The type strain of Marinobacter nitratireducens is AK21T ( = MTCC 11704T = JCM 18428T).

Yamadazyma insecticola f.a., sp. nov. and Yamadazyma epiphylla f.a., sp. nov., two novel yeast species

Two yeast strains representing two novel yeast species were isolated from frass of an unidentified insect (ST-78T) and the external surfaces of rice leaves (YE170T) collected in Thailand. The two strains were genetically, morphologically and phenotypically distinct from recognized species and were found to represent two novel species of the genus Yamadazyma although formation of ascospores was not observed. In terms of pairwise sequence similarity of the D1/D2 region of the large subunit rRNA gene, the closest relative of strain ST-78T was Candida lessepsii CBS 9941T but with 3.8 % nucleotide substitutions, while the closest relative of strain YE170T was strain ST-78T but with 4.3 % nucleotide substitutions. Analysis of the sequences of the internal transcribed spacer 1 and 2 (ITS1–2) regions revealed that strain ST-78 differed from C. lessepsii CBS 9941T by 8.8 % nucleotide substitutions and from strain YE170T by 9.4 % nucleotide substitutions. The result of pairwise sequence similarity of the D1/D2 and ITS1–2 regions together with phylogenetic analysis indicated that strains ST-78T and YE170T represented two novel species within the Yamadazyma clade. The names Yamadazyma insecticola f.a., sp. nov. (type strain ST-78T = BCC 8314T = NBRC 110421T = CBS 13382T; MycoBank no. MB810546) and Yamadazyma epiphylla f.a., sp. nov. (type strain YE170T = BCC 63466T = NBRC 110423T = CBS 13384T; MycoBank no. MB810547) are proposed for the two novel yeast species.

Pseudomonas matsuisoli sp. nov., isolated from a soil sample

An aerobic, Gram-stain-negative, rod-shaped and polar-flagellated bacterium, designated strain CC-MHH0089T, was isolated from a soil sample taken on Matsu Island (Taiwan). Strain CC-MHH0089T grew at 15–30 °C and pH 5.0–10.0 and tolerated ≤8 % (w/v) NaCl. 16S rRNA gene sequence analysis showed high pairwise sequence similarity to Pseudomonas azotifigens 6H33bT (97.3 %) and Pseudomonas balearica SP1402T (96.7 %) and lower sequence similarity to other strains (<96.0 %). In DNA–DNA reassociation experiments, the relatedness of strain CC-MHH0089T to P. azotifigens JCM 12708T was 38.3 % (reciprocal value 19.5 %). Evolutionary trees reconstructed on the basis of 16S rRNA, gyrB and rpoB gene sequences revealed a varying phylogenetic neighbourhood of strain CC-MHH0089T with regard to the most closely related type strains. The predominant quinone system was ubiquinone 9 (Q-9) and the DNA G+C content was 63.6 mol%. The major fatty acids were C12 : 0, C16 : 0, C17 : 0, C19 : 0 cyclo ω8c and summed features 2 (C14 : 0 3-OH/iso-C16 : 1 I), 3 (C16 : 1ω7c/C16 : 1ω6c) and 8 (C18 : 1ω7c/C18 : 1ω6c). The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. According to its distinct phylogenetic, phenotypic and chemotaxonomic features, strain CC-MHH0089T is proposed to represent a novel species within the genus Pseudomonas , for which the name Pseudomonas matsuisoli sp. nov. is proposed. The type strain is CC-MHH0089T ( = BCRC 80771T = JCM 30078T).

Methylobacterium pseudosasicola sp. nov. and Methylobacterium phyllostachyos sp. nov., isolated from bamboo leaf surfaces

Two strains of Gram-negative, methylotrophic bacteria, isolated because of their abilities to promote plant growth, were subjected to a polyphasic taxonomic study. The isolates were strictly aerobic, motile, pink-pigmented, facultatively methylotrophic, non-spore-forming rods. The chemotaxonomic characteristics of the isolates included the presence of C18 : 1ω7c as the major cellular fatty acid. The DNA G+C contents of strains BL36T and BL47T were 69.4 and 69.8 mol%, respectively. 16S rRNA gene sequence analysis of strains BL36T and BL47T placed them under the genus Methylobacterium, with the pairwise sequence similarity between them and the type strains of closely related species ranging from 97.2 to 99.0 %. On the basis of their phenotypic and phylogenetic distinctiveness and the results of DNA–DNA hybridization analysis, the isolates represent two novel species within the genus Methylobacterium , for which the names Methylobacterium pseudosasicola sp. nov. (type strain BL36T = NBRC 105203T = ICMP 17621T) and Methylobacterium phyllostachyos sp. nov. (type strain BL47T = NBRC 105206T = ICMP 17619T) are proposed.