- Volume 68, Issue 11, 2018

Strain 6GN-30T, a Gram-stain-negative, aerobic, non-spore-forming, rod-shaped, motile bacterium was isolated from Ephedra sinica roots in the Kumtag Desert. On the basis of the 16S rRNA gene sequence, the isolate represented a member of the genus Mesorhizobium of the family Phyllobacteriaceae . The results of a phylogenetic analysis indicated that 6GN-30T was phylogenetically related to Mesorhizobium soli NHI-8T. Strain 6GN-30T grew at a salinity of 0–1.0 % (w/v) NaCl (with optimum growth in the absence of NaCl), pH 6.0–9.0 (optimum 7.0–8.0) and 15–45 °C. The major cellular fatty acids were summed feature 8 (C_18 : 1ω7c/C_18 : 1ω6c), C_19 : 0cyclo ω8c, iso-C_17 : 0, C_18 : 0, and C_16 : 0. The draft genome of 6GN-30T was 6.11 Mb long, with a DNA G+C content of 66.4 mol%. The average nucleotide identity to M. soli NHI-8T was 84.32 %. The strain contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine,aminophospholipids and phospholipids. The chemotaxonomic, phylogenetic and phenotypic data indicate that 6GN-30T represents a novel species of the genus Mesorhizobium for which the name Mesorhizobium ephedrae sp. nov. is proposed. The type strain is 6GN-30T (=ACCC 60073T=KCTC 62410T).

A novel bacterial strain, designated PR1016AT, was isolated from a car air conditioning system. This rod-shaped strain showed catalase and oxidase activities, was aerobic and methylotrophic, and had a reddish pink colour. The genomic DNA G+C content of strain PR1016AT was 70.2 mol%, as determined by genome sequencing. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain PR1016AT was most closely related to Methylobacterium aquaticum GR16T (98.86 %), M. variabile GR3T (98.43 %), M. platani PMB 02T (98.36 %) and M. tarhaniae N4211T (98.14 %). The average nucleotide identity and digital DNA–DNA hybridization values between strain PR1016AT and M. aquaticum GR16T, M. platani PMB02T and M. variabile GR3T were 88.61, 88.14 and 87.88 %, and 36.4, 35.8 and 34.7 %, respectively. Numerous insertion sequences are present in the genome of strain PR1016AT, which has a larger genome than the four Methylobacterium species described above. Cells grew at 18–42 °C (optimum, 30 °C), at pH 4.0–9.0 (optimum, pH 7.0) and in the presence of 0–1.0 % (w/v) NaCl (optimum, 0 %). The major respiratory quinone was Q10. Fatty acid methyl ester analysis revealed that summed feature 8 (C_18 : 1ω7c and/or C_18 : 1ω6c) was the predominant cellular fatty acid in strain PR1016AT. Two-dimensional TLC indicated that the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The genotypic and phenotypic characteristics indicate that strain PR1016AT represents a novel species of the genus Methylobacterium , for which the name Methylobacterium currus sp. nov. is proposed. The type strain is PR1016AT (=KACC 19662T=JCM 32670T).

A Gram-stain-negative, aerobic, motile bacterial strain, shQ-4T, was isolated from a pear tree in Henan Province, China. The strain grew at 10–41 °C, at pH 4.0–8.0 and in the presence of 1–3 % (w/v) NaCl. It shared highest 16S rRNA gene sequence similarity (96.66 %) with Herbaspirillum chlorophenolicum CPW301T. The phylogenetic tree based on 16S rRNA gene sequences showed that strain shQ-4T formed a distinct branch next to reference species in the genus Herbaspirillum . The profile of major polar lipids of strain shQ-4T contained phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and an unidentified aminophospholipid (APL). The major respiratory quinone was Q-8. The major fatty acids of this strain were C_16 : 0, summed feature 3 (C_16 : 1ω6c/C_16 : 1ω7c), C_17 : 0 cyclo and C_18 : 0. Strain shQ-4T is considered to represent a novel species of the genus Herbaspirillum , with the proposed name Herbaspirillum piri sp. nov. The type strain is shQ-4T (=CFCC 14641T=KCTC 52804T).

Strain DMKU13-2T, representing a novel anamorphic yeast species in the class Microbotryomycetes, subphylum Puccinomycotina, phylum Basidiomycota, was isolated from a soft coral collected in the sea off Ko Mu island, Thailand. The phylogenetic analysis based on the concatenated sequences of the internal transcribed spacer (ITS) region and the D1/D2 region of the large subunit ribosomal RNA (LSU rRNA) gene indicated that this strain was a novel species in the genus Spencerozyma and distant from Spencerozyma crocea, the only species of the genus. The novel species differed from the type of S. crocea (CBS 2029T) by 5.2 % nucleotides (31 nucleotide substitutions out of 594 bp) in the D1/D2 region of the LSU rRNA gene and 9.0 % nucleotides (66 nucleotide substitutions out of 735 bp) in the ITS region. The name Spencerozyma siamensis sp. nov. is proposed. The type is DMKU13-2T (=CBS 14683=TBRC 7039). The MycoBank number is MB 824889.

Nontuberculous mycobacteria, particularly the Mycobacterium avium complex (MAC) bacteria, are increasingly recognized as opportunistic pathogens of humans. As a result, studies on antibiotic treatment and taxonomy of the MAC are intensifying, but an updated definition of what constitutes the MAC, either for taxonomical studies or for clinical purposes, is lacking. On the basis of literature review and phylogenetic analyses, we propose to define the MAC as a grouping of slow-growing mycobacteria that show corresponding values in at least two of the following targets against either M. avium ATCC 25291T or Mycobacterium intracellulare ATCC 13950T: >99.4 % sequence identity for the full 16S rRNA gene, >98.7 % for the partial (5′) 16S rRNA gene, >97.3 % for hsp65 and >94.4 % for rpoB region V. A >97.5 % value in concatenated analyses of >2500 bp that includes 16S rRNA, hsp65 and rpoB gene sequence data or ≥85 % average nucleotide identity to M. avium ATCC 25291T or M. intracellulare ATCC 13950T on basis of whole genome sequencing data is recommended. This molecular definition is based on the distances observed between the classical members of the MAC, M. avium and M. intracellulare . Applying this definition, the complex currently consists of 12 validly published species: Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium chimaera, Mycobacterium colombiense, Mycobacterium arosiense, Mycobacterium vulneris, Mycobacterium bouchedurhonense, Mycobacterium timonense, Mycobacterium marseillense, Mycobacterium yongonense, Mycobacterium paraintracellulare and Mycobacterium lepraemurium.