The taxonomic positions of two novel strains isolated from a soil sample collected in Japan using Glucose-Peptone-Meat extract (GPM) agar plates supplemented with superoxide dismutase or superoxide dismutase plus catalase were investigated based on the results of chemotaxonomic, phenotypic and genotypic characteristics. Strains were Gram-positive, catalase-positive, non-motile bacteria with L-ornithine as a diagnostic diamino acid of the peptidoglycan. The acyl type of the peptidoglycan was N-glycolyl. The major menaquinones were MK-12 and 13. Mycolic acids were not detected. The G+C content of the DNA was 70 mol%. Comparative 16S rRNA studies on the two isolated strains revealed that they belong to the genus Microbacterium. DNA-DNA relatedness data revealed that KV-448T and KV-769 are a new species of the genus Microbacterium. From these results, we propose that these bacteria should be classified in the genus Microbacterium as Microbacterium terricolae sp. nov. The type strain of Microbacterium terricolae is KV-448T (=NRRL B-24468T, NBRC 101801T).
Eighteen rod-shaped homofermentatives, six heterofermentatives, and a coccal homofermentative lactic acid bacteria were isolated from fermented tea leaves (miang) produced in the northern part of Thailand. The isolates were placed in a monophyletic cluster consisting of Lactobacillus and Pediococcus species. They were divided into seven groups by phenotypic and chemotaxonomic characteristics, DNA-DNA similarity, and 16S rRNA gene sequences. Groups I to VI belonged to Lactobacillus and Group VII to Pediococcus. All of the strains tested produced DL-lactic acid but those in Group IV produced L-lactic acid. The strains tested in Groups I, II and V had meso-diaminopimelic acid in the cell wall. Six strains in Group I were identified as Lactobacillus pantheris; five strains in Group II as Lactobacillus pentosus; and four strains in Group V as Lactobacillus suebicus. Two strains in Group VI showed high DNA-DNA similarity for each other and MCH4-2 was closest to Lactobacillus fermentum CECT 562T with 99.5% of 16S rRNA gene sequence similarity. Five strains in Group III are proposed as Lactobacillus thailandensis sp. nov., and MCH5-2T (BCC 21235T=JCM 13996T=NRIC 0671T=PCU 272T) is the type strain which has 49 mol% G+C of DNA. Two strains in Group IV are proposed as Lactobacillus camelliae sp. nov., and the type strain is MCH3-1T (BCC 21233T=JCM 13995T=NRIC 0672T=PCU 273T) which has 51.9 mol% G+C of DNA. One strain in Group VII is proposed as Pediococcus siamensis sp. nov., and MCH3-2T (BCC 21234T=JCM 13997T=NRIC 0675T=PCU 274T) is the type strain which has 42 mol% G+C of DNA.
Two nonribosomal peptide synthetase genes responsible for the biosynthesis of microcystin and micropeptin in Microcystis aeruginosa K-139 have been identified. A new nonribosomal peptide synthetase gene, psm3, was identified in M. aeruginosa K-139. The gene is a cluster extending 30 kb and comprising 13 bidirectionally transcribed open reading frames arranged in two putative operons. psm3 encodes four adenylation proteins, one polyketide synthase, and several unique proteins, especially Psm3L consisting of halogenase, acyl-CoA binding protein-like protein, and acyl carrier protein. Alignment of the binding pocket of the adenylation domain and an ATP-PPi exchange analysis using a recombinant protein with the adenylation domain of Psm3B showed that Psm3G and Psm3B activate aspartic acid and tyrosine, respectively. Although disruption of psm3 did not reveal the product produced by Psm3, we identified microviridin B and aeruginosin K139 in the cells of M. aeruginosa K-139. The above-mentioned results indicated that M. aeruginosa possesses at least five nonribosomal peptide synthetase gene clusters.
Two actinomycete strains, 2-19(6)T and 2-30-b(28)T, which produced single, non-motile noduler to warty spore surfaces, were isolated from sandy soil in Chokoria, Cox's Bazar, Bangladesh. A polyphasic study was carried out to establish the taxonomic position of these strains. Morphological and chemotaxonomic characteristics of these strains coincided with those of the genus Micromonospora. Phylogenetic analysis using 16S rDNA sequences indicated that these strains should be classified in the genus Micromonospora. The 16S rDNA sequence of strain 2-19(6)T showed closest similarity to the type strains of M. mirobrigensis (98.9%) and M. carbonacea (98.8%), and the strain 2-30-b(28)T to the type strains of M. purpureochromogenes (99.4%), M. halophytica (99.3%) and M. aurantiaca (99.2%). Furthermore, a combination of DNA-DNA hybridization results and some differential physiological and biochemical properties indicated that these strains were distinguished from the phylogenetically closest relatives. These strains therefore represent two novel species, for which the name Micromonospora chokoriensis sp. nov. and Micromonospora coxensis sp. nov. are proposed. The type strains are 2-19(6)T (=JCM 13247T =MTCC 8535T) and 2-30-b(28)T (=JCM 13248T=MTCC 8093T).
Three actinomycete strains were isolated from soil samples collected in Bangladesh. The cultures formed spherical sporangia on short sporangiophores directly above the surface of the substrate mycelium. The sporangia developed singly or in clusters and each sporangium contained several nonmotile spherical to oval spores with a smooth surface. The strains 3-9(24)T, 3-21(27) and 7-40(26)T contained meso-diaminopimelic acid in the cell walls, predominant menaquinone MK-9(H6) and MK-9(H4) and glucose, xylose, galactose, mannose, rhamnose, ribose and arabinose in the whole-cell hydrolysates. Diagnostic phospholipid is phosphatidylethanolamine and branched anteiso-C17 : 0 (30.0–38.0%), anteiso-C15 : 0 (12.5–14.0%), iso-C16 : 0 (10.0–15.0%) and iso-C15 : 0 (10.0–12.0%) were detected as the major cellular fatty acids. The acyl type of the peptidoglycan was glycolyl and mycolic acids were not detected. The G+C content of the DNA was 71 mol%. The chemotaxonomic data indicate that these strains belong to the family Micromonosporaceae. Phylogenetic analysis based on 16S rRNA gene sequence data suggested that the strains 3-9(24)T, 3-21(27) and 7-40(26)T fall within the family Micromonosporaceae. On the basis of phylogenetic analysis and characteristic patterns of signature nucleotides as well as morphological and chemotaxonomic data, Luedemannella gen. nov. is proposed for our 3 isolates. DNA-DNA hybridization experiment and phenotypic characterization indicated that the new genus was constituted of 2 species, as Luedemannella helvata sp. nov. for the strain 3-9(24)T (=JCM 13249T=MTCC 8091T) and Luedemannella flava for the strain 7-40(26)T (=JCM 13250T=MTCC 8095T) in the family Micromonosporaceae.