International journal of systematic and evolutionary microbiology最新文献

Fifteen Gram-stain-negative, rod-shaped bacterial strains, motile by means of a monopolar flagellum, were isolated from glaciers located on the Tibetan Plateau, P.R. China. These strains, designated MDT1-19^T, MDB2-8^T, HLS12-2^T, HLX7-2^T, LB2P49^T, LB2P70^T, LB3P112^T, LB3P118^T, LB2P10^T, RB2R34^T, ZB1P44^T, RB2P8^T, GB1R12^T, GB4P2^T and RT4P48^T, belong to the genus Janthinobacterium based on 16S rRNA gene sequences analysis. The average nucleotide identity and digital DNA-DNA hybridization values between these strains and species with validly published names were below 96% and 70%, respectively. Based on the phylogenetic, genotypic and phenotypic evidence, these 15 strains are proposed to represent fifteen novel species within the genus Janthinobacterium, with the following proposed names: Janthinobacterium algoris sp. nov. (MDT1-19^T=CGMCC 1.9797=NBRC 116353^T), Janthinobacterium breve sp. nov. (MDB2-8^T=CGMCC 1.9853^T=NBRC 116354^T), Janthinobacterium darwini sp. nov. (HLS12-2^T=CGMCC 1.9980^T=NBRC 116355^T), Janthinobacterium woesei sp. nov. (HLX7-2^T=CGMCC 1.9990^T=NBRC 116356^T), Janthinobacterium salmonicoloratum sp. nov. (LB2P49^T=CGMCC 1.11246^T=NBRC 116357^T), Janthinobacterium violaceum sp. nov. (LB2P70^T=CGMCC 1.11252^T=NBRC 116358^T), Janthinobacterium leeuwenhoeki sp. nov. (LB3P112^T=CGMCC 1.11294^T=NBRC 116359^T), Janthinobacterium pasteuri sp. nov. (LB3P118^T=CGMCC 1.11299^T=NBRC 116360^T), Janthinobacterium paucivorans sp. nov. (LB2P10^T=CGMCC 1.11332^T=NBRC 116361^T), Janthinobacterium longum sp. nov. (RB2R34^T=CGMCC 1.11894^T=NBRC 116362^T), Janthinobacterium glycogeni sp. nov. (ZB1P44^T=CGMCC 1.23234^T=NBRC 116363^T), Janthinobacterium kochi sp. nov. (RB2P8^T=CGMCC 1.23776^T=NBRC 116364^T), Janthinobacterium goodfellowi sp. nov. (GB1R12^T=CGMCC 1.24272^T=NBRC 116365^T), Janthinobacterium lyxosi sp. nov. (GB4P2^T=CGMCC 1.24307^T=NBRC 116366^T) and Janthinobacterium amylolyticum sp. nov. (RT4P48^T=CGMCC 1.24355^T=NBRC 116367^T).

Two novel endophytic actinomycete strains, NRAIS3^T and NRAIS4, belonging to the genus Streptomyces, were isolated from Mitragyna speciosa leaves. Their taxonomic status was determined using a polyphasic approach. Both strains grew at temperatures ranging from 25 to 37 °C and at pH values between 6 and 10. Strain NRAIS3ᵀ tolerated up to 5% (w/v) NaCl, whereas strain NRAIS4 tolerated up to 7% (w/v) NaCl. Both strains contained ll-diaminopimelic acid in their cell-wall peptidoglycan, and their whole-cell hydrolysates contained ribose and glucose. The predominant cellular fatty acids were anteiso-C_15:0, anteiso-C_17 : 0, iso-C_16:0 and iso-C_15:0. The polar lipids detected included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. Based on 16S rRNA gene sequence analysis, strains NRAIS3^T and NRAIS4 showed the highest similarity (99.4%) to the type strains Streptomyces fodineus TW1S1^T, Streptomyces puniciscabiei DSM 41929^T and Streptomyces filipinensis JCM 4369^T. The average nucleotide identity based on MUMmer and digital DNA-DNA hybridization values between the genomes of the two strains and those of related type strains were significantly below the Streptomyces species delineation thresholds of 96.7% and 70%, respectively. The ethyl acetate crude extract of NRAIS3^T exhibited antibacterial activity against Gram-positive and Gram-negative pathogenic bacteria. It showed the highest activity against Listeria monocytogenes ATCC 7644, followed by Staphylococcus epidermidis ATCC 12228, and Enterococcus faecium ATCC 35667. Liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry analyses revealed diverse antimicrobial metabolites, including aminoquinolines, ergopeptines, isoflavones, hydroxycinnamic acids, N-alkyl piperazines, benzotriazoles, benzimidazoles, phenylacetamides, as well as volatile compounds such as 2,5,5-trimethylcyclohexane-1,3-dione, hexamethyl-cyclotrisiloxane and 1,4-bis(trimethylsilyl) benzene. Based on the taxonomic results, strains NRAIS3^T and NRAIS4 represent a novel species within the genus Streptomyces, for which the name Streptomyces mitragynae sp. nov. is proposed. The type strain is NRAIS3^T (=LMG 34056^T=TBRC 20459^T).

A peach-pigmented strain FW153^T and a yellow-pigmented FW199^T were isolated from marsh water located at Fort Whyte, Manitoba, Canada. Both produce an anoxygenic photosynthetic apparatus, with a reaction centre encircled by a light-harvesting I complex containing bacteriochlorophyll a. They do not produce RuBisCo and do not grow anaerobically or autotrophically, supporting the classification of both as aerobic anoxygenic phototrophs. Sequencing of the 16S rRNA gene showed similarity to Rhizorhabdus phycosphaerae (99.93%), Rhizorhabdus wittichii (98.73%) and Rhizorhabdus histidinilytica (98.52%) for FW153^T, while for FW199^T, it was Sphingomonas molluscorum (97.47%), Sphingomonas dokdonensis (97.44%) and Sphingomonas kyeonggiensis (97.08%). Polyphasic analysis identified differences in physiology and cellular fatty acid composition, as well as within the genome, with average nucleotide identity (<95%) and digital DNA-DNA hybridization values (<70%) between each strain and their closest relatives supporting species designation. Therefore, we propose that FW153^T (=NCIMB 15610^T=DSM 120042^T) and FW199^T (=NCIMB 15611^T=DSM 120043^T) be classified as the type strains of new species with the names Rhizorhabdus antheiae sp. nov. and Sphingomonas eleionomae sp. nov., respectively.

Seven strains representing a novel ascomycetous yeast species were isolated from the leaf phylloplane (DMKU-SG60) and the floral surface (DMKU-FF11, DMKU-FF12, DMKU-FD2, DMKU-FD6, DMKU-FS1 and ST-387) of mangrove trees in Thailand. Pairwise sequence analysis indicated that the strains were identical or differed by one to two nucleotide substitution(s) in the D1/D2 domains of the large subunit (LSU) rRNA gene. They also were identical or differed by one to four nucleotide substitution(s) in the internal transcribed spacer (ITS) region. blastn searches of the GenBank database revealed that the closest related species was Metschnikowia rancensis, differing by 28 (5.5-6.0%) and 30-33 (8.0-8.9%) nucleotide substitutions in the D1/D2 domains of the LSU rRNA gene and the ITS region, respectively. Moreover, whole-genome sequencing was used to further confirm the separation of this species. In comparison with other related species, average nucleotide identity values of 74.6-76.5% and digital DNA-DNA hybridization values of 12.8-13.3% were obtained. Phylogenetic analysis based on the concatenated sequences of the ITS region and the D1/D2 domains of the LSU rRNA gene, as well as phylogenomic analysis, showed that these strains belong to the genus Metschnikowia, but at a distinct position relative to other recognized species. Based on molecular analyses and phenotypic characteristics, the strains represent a novel species, for which the name Metschnikowia sanitii f.a., sp. nov. is proposed. The holotype is TBRC 19861^T, and the ex-type culture is PYCC 10335 (DMKU-FF11). The MycoBank number is MB 860254.

Two Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated AW1-3^T (strictly aerobic) and AW1-7 ^T (facultatively aerobic), both catalase- and oxidase-positive, were isolated from a reed wetland in South Korea. Strain AW1-3^T grew at 15-35 °C, pH 6.0-7.0 and in 0.0-0.5% (w/v) NaCl, whereas strain AW1-7^T grew at 10-35 °C, pH 6.0-7.0 and in 0-0.5% NaCl. The major fatty acids (>10%) were iso-C_15:0 and summed feature 3 (C_16:1  ω7c and/or C_16 :1  ω6c) in strain AW1-3^T and C_16:0, summed feature 3, C_18:0 and iso-C_15:0 in strain AW1-7^T. Phosphatidylethanolamine was the major polar lipid in both strains, and menaquinone-7 was the sole respiratory quinone. The genomic DNA G+C contents were 43.9 mol% (AW1-3^T) and 43.2 mol% (AW1-7^T). The two strains shared 94.9% 16S rRNA gene sequence similarity, with ANI and dDDH values of 70.9% and 20.0%, respectively, indicating they represent distinct species. Phylogenetic and phylogenomic analyses based on 16S rRNA gene and whole-genome sequences placed strains AW1-3^T and AW1-7^T in close association with Mucilaginibacter rivuli HMF5004ᵀ and Mucilaginibacter ginsenosidivorax KHI28ᵀ, respectively. However, strain AW1-3^T shared 16S rRNA gene sequence similarity/ANI/dDDH values of 97.7%/73.7%/19.8% with M. rivuli HMF5004^T, and strain AW1-7ᵀ shared 98.5%/88.6%/36.6% with M. ginsenosidivorax KHI28ᵀ, all below the species delineation thresholds, supporting their recognition as novel species. Based on phenotypic, chemotaxonomic and genomic characteristics, the names Mucilaginibacter aureus sp. nov. (AW1-3^T=KACC 23848^T=JCM 37500^T) and Mucilaginibacter sediminis sp. nov. (AW1-7^T=KACC 23849^T=JCM 37501^T) are proposed.

A novel Agromyces strain, designated as M3QZ16-3^T, was isolated from the rhizosphere soil of Excoecaria agallocha, collected from the Maowei Sea Mangrove Nature Reserve in the Guangxi Zhuang Autonomous Region, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain M3QZ16-3^T was closely related to species of the genus Agromyces and shared the highest similarity of 99.26% with Agromyces kandeliae Q22^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain M3QZ16-3^T and the type strain of A. kandeliae Q22^T were 88.2% and 34.4%, respectively. The polar lipids of strain M3QZ16-3^T comprised diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid, one unidentified polar lipid and two unidentified lipids. The major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0, iso-C_15:0 and iso-C_16:0, and the predominant menaquinones (MK; vitamin K₂) were MK-12 (78.3%) and MK-11 (14.3%). Cell-wall amino acids were 2,4-diaminobutyric acid, glutamic acid, glycine and alanine. The genome size of strain M3QZ16-3^T was 3.8 Mb, with a DNA G+C content value of 71.7 mol%. Based on the above descriptions, we propose strain M3QZ16-3^T to represent a novel species of the genus Agromyces, for which the name Agromyces excoecariae sp. nov. is proposed. The type strain is M3QZ16-3^T (=MCCC 1K07179^T=JCM 34940^T).

The obligately anaerobic, Gram-stain-positive coccobacilli strains OB7620^T and OB7656^T were isolated from faecal samples of healthy Japanese volunteers. Strain OB7620^T showed the highest 16S rRNA gene sequence similarity to Coprococcus comes ATCC 27758^T (98.4%) and Clostridium nexile DSM 1787^T (96.3%). Strain OB7656^T showed the highest 16S rRNA gene sequence similarity to 'Gluceribacter canis' NATH-2371^T (97.7%), C. nexile DSM 1787^T (94.8%) and Faecalimonas umbilicata EGH7^T (94.8%). These findings indicate that the two strains represent novel species. Genomic analysis clarified the phylogenetic relationship of C. comes with the species cluster designated as Coprococcus sensu stricto, which includes the type species, C. eutactus. As C. comes is distinct from the species of Coprococcus sensu stricto, C. comes is reclassified into a novel genus, Allocoprococcus, as Allocoprococcus comes gen. nov., comb. nov. Although strain OB7620^T is closely related to C. comes, it is a distinct species. Therefore, we propose the name Allocoprococcus similis gen. nov., sp. nov. The type strain is OB7620^T (=DSM 118890^T=JCM 37173^T). Because Coprococcus catus differs from Coprococcus sensu stricto, it has been placed in a novel genus, Pseudocoprococcus, as Pseudocoprococcus catus gen. nov., comb. nov. We also concluded that Coprococcus immobilis and Coprococcus intestinihominis are the same species and belong to the new genus Pseudocoprococcus. As C. immobilis has priority, we propose the name Pseudocoprococcus immobilis gen. nov., comb. nov. We also concluded that C. nexile and Clostridium phoceensis are the same species in the genus Faecalimonas. As C. nexile has priority, we propose the name Faecalimonas nexilis comb. nov. Coprococcus mobilis and 'G. canis' should also be reclassified within the genus Faecalimonas. Therefore, we propose the name Faecalimonas mobilis comb. nov. and Faecalimonas canis sp. nov. As strain OB7656^T is related to 'G. canis' but is a different species, we propose the name Faecalimonas hominis sp. nov. The type strain is OB7656^T (=DSM 118889^T=JCM 37172^T).