Genome-based reclassification of Paenibacillus jamilae Aguilera et al. 2001 as a later heterotypic synonym of Paenibacillus polymyxa (Prazmowski 1880) Ash et al. 1994.

Paenibacillus is one of the genera that has high species diversity and Paenibacillus polymyxa, the type species of the genus, is mainly isolated from plant-associated environments. Among the plant-associated species, Paenibacillus jamilae B.3T (=CECT 5266T=DSM 13815T=KACC 10925T=KCTC 13919T) was proposed to be a novel species according to 16S rRNA gene similarity and DNA-DNA relatedness with related species, including Paenibacillus polymyxa. Nevertheless, in the description of Paenibacillus jamilae the used strain of Paenibacillus polymyxa was not the type strain of this species. In this work we found that the type strains of both species showed 16S rRNA gene similarity of 99.6 %. Therefore, in this study, we sequenced the genome of Paenibacillus jamilae KACC 10925T and compared it with those of the type strain of Paenibacillus polymyxa ATCC 842T and other phylogenetically related species. Genome relatedness value calculated by DNA-DNA hybridization between type strains of Paenibacillus polymyxa and Paenibacillus jamilae was 73.5 %, which is higher than the threshold value (70 %). For more objective and repeatable results of genome relatedness, we analysed an average nucleotide identity (ANI) between two strains. Our results showed that ANI value between the type strains of Paenibacillus jamilae and Paenibacillus polymyxa is 98.5 %, a phylogenetic distance also higher than the threshold values (95~96 %). These values were proposed by Yoon et al. (2017). In addition, their phylogenetic distance based on 92 bacterial core genes is highly close compared to other species. These mean that Paenibacillus jamilae and Paenibacillus polymyxa should be reclassified as a single species. Based on the results from genomic level comparison as well as reexamination results of physiological and chemotaxonomic features, we propose reclassification of Paenibacillus jamilae as a later heterotypic synonym of Paenibacillus polymyxa.

Genome-based reclassification of Weissella jogaejeotgali as a later heterotypic synonym of Weissella thailandensis.

Members of the genus Weissella are mostly found in fermented plant material. Among the Weissella species, two species, Weissella thailandensis and Weissella jogaejeotgali, were isolated from foods fermented from marine animals. The two species showed a high level of 16S rRNA gene similarity (99.39 %), whereas they exhibited a moderate level of DNA-DNA hybridization relatedness (63.9 %) in an earlier study. In this study, we determined the whole genome sequence of W. thailandensis KCTC 3751T and compared it to those of W. jogaejeotgali FOL01T and other related species. The average nucleotide identity value between the type strains of W. thailandensis and W. jogaejeotgali was 96.4 %, which is clearly higher than the cut-off proposed for bacterial species. We, therefore, propose to reclassify W. jogaejeotgali as a later heterotypic synonym of W. thailandensis.

Blastococcus atacamensis sp. nov., a novel strain adapted to life in the Yungay core region of the Atacama Desert.

A polyphasic study was undertaken to establish the taxonomic status of a Blastococcus strain isolated from an extreme hyper-arid Atacama Desert soil. The isolate, strain P6T, was found to have chemotaxonomic and morphological properties consistent with its classification in the genus Blastococcus. It was shown to form a well-supported branch in the Blastococcus 16S rRNA gene tree together with the type strains of Blastococcus capsensis and Blastococcus saxobsidens and was distinguished from the latter, its close phylogenetic neighbour, by a broad range of phenotypic properties. The draft genome sequence of isolate P6T showed 84.6 % average nucleotide identity, 83.0 % average amino acid identity and a digital DNA-DNA hybridisation value of 27.8 % in comparison with the genome sequence of B. saxobsidens DSM 44509T, values consistent with its assignment to a separate species. Based on these data it is proposed that isolate P6T (NCIMB 15090T=NRRL B-65468T) be assigned to the genus Blastococcus as Blastococcus atacamensis sp. nov. Analysis of the whole genome sequence of B. atacamensis P6T, with 3778 open reading frames and a genome size of 3.9 Mb showed the presence of genes and gene clusters that encode for properties that reflect its adaptation to the extreme environmental conditions that prevail in Atacama Desert soils.

Leeuwenhoekiella polynyae sp. nov., isolated from a polynya in western Antarctica.

A Gram-stain-negative, motile by gliding, rod-shaped bacterial strain, designated SOJ2014-1(T) was isolated from surface water of a polynya in the Antarctic Ocean. A comparative 16S rRNA gene sequence analysis showed that strain SOJ2014-1(T) belongs to the genus Leeuwenhoekiella and is most closely related to Leeuwenhoekiella marinoflava DSM 3653(T) (97.5% 16S rRNA gene sequence similarity). The G+C content of the genomic DNA of strain SOJ2014-1(T) was 38.8 mol%. Its predominant cellular fatty acids were summed feature 3 (composed of C16 : 1ω6c and/or C16 : 1ω7c), iso-C17 : 0 3-OH, iso-C15 : 0, iso-C15 : 1 G and summed feature 9 (composed of iso-C17 : 1ω9c and/or 10-methyl C16 : 0). DNA-DNA relatedness between strain SOJ2014-1(T) and close relatives, L. marinoflava DSM 3653(T) and Leeuwenhoekiella aequorea LMG 22550(T), was below 49%. The respiratory quinone was MK-6. The major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The strain grew at 0-35 °C (optimum, 25 °C) with 0-14.0% (w/v) NaCl (optimum, 1.0-5.0%). It was strictly aerobic and had different carbohydrate utilization traits compared with L. marinoflava DSM 3653(T). Based on the phenotypic, chemotaxonomic and phylogenetic analyses, strain SOJ2014-1(T) is proposed as a representative of a novel species, Leeuwenhoekiella polynyae. The type strain is SOJ2014-1(T) ( =KCTC 42185(T) =JCM 30387(T)).

Triglyceride-Catabolizing Lactiplantibacillus plantarum GBCC_F0227 Shows an Anti-Obesity Effect in a High-Fat-Diet-Induced C57BL/6 Mouse Obesity Model.

Given the recognized involvement of the gut microbiome in the development of obesity, considerable efforts are being made to discover probiotics capable of preventing and managing obesity. In this study, we report the discovery of Lactiplantibacillus plantarum GBCC_F0227, isolated from fermented food, which exhibited superior triglyceride catabolism efficacy compared to L. plantarum WCSF1. Molecular analysis showed elevated expression levels of α/ß hydrolases with lipase activity (abH04, abH08_1, abH08_2, abH11_1, and abH11_2) in L. plantarum GBCC_F0227 compared to L. plantarum WCFS1, demonstrating its enhanced lipolytic activity. In a high-fat-diet (HFD)-induced mouse obesity model, the administration of L. plantarum GBCC_F0227 mitigated weight gain, reduced blood triglycerides, and diminished fat mass. Furthermore, L. plantarum GBCC_F0227 upregulated adiponectin gene expression in adipose tissue, indicative of favorable metabolic modulation, and showed robust growth and low cytotoxicity, underscoring its industrial viability. Therefore, our findings encourage the further investigation of L. plantarum GBCC_F0227's therapeutic applications for the prevention and treatment of obesity and associated metabolic diseases.