白色杆菌属一新种的分离鉴定及其系统发育学分析

从热带土壤中分离到一株好氧、革兰氏阳性、不产芽孢的杆状菌株F8，该菌株含有MK11为主要醌组份；细胞壁肽聚糖的氨基酸组分为2，4氨基丁酸和γ氨基丁酸等；细胞壁糖组分为鼠李糖、半乳糖和葡萄糖；DNA的G+C含量为68mol%。16SrRNA基因测序和系统发育学分析的结果表明，菌株F8与驹形白色杆菌(Leucobacter komagatae)亲缘关系最近，其16S rRNA基因的同源率为96%。两者的总DNA杂交率为62%，生理生化特征也有差异，故可把菌株F8定为一个新种，即热带白色杆菌(Leucobacter tropicalissp.nov.)。

CHARACTERIZATIONANDPHYLOGENETICANALYSISOFTHENEW SPECIESOFTHE LEUCOBACTERTROPICALISSP.NOV.

A new aerobic, gram-positive, non-sporulating, rod-shaped organism is described. Strain F-8 was isolated from tropical soil, and has the following characteritics: the menaquinone contains a side chain with 11 isoprenyl units(MK-11); 2,4-diaminobutyric acid, glutamic acid, alanine, glycine and a small amount of gamma-aminobutyric acid present in the cell wall at a molar ratio of 0.77:1.0:1.66:0.95. The major cellular sugar were rhamnose, galactose and glucose. The G + C content of DNA is 68 mol%. The 16S rRNA gene was amplified, cloned and sequenced, a phylogenetic tree was constructed on the 16S rRNA gene sequences. The tree clearly indicated that strain F-8 forming the same lineage with leucobacter komagatae, the level of binary sequence similarity between strain F-8 and L. komagatae is 96%. Based on the characteristics, allow the placement of strain F-8 into the genus Leucobacter, but F-8 showed some differences in biochemical and physical characters from the reported species L. komagae. A new species name, Leucobacter tropicalis sp. nov. was proposed for this isolate. The type strain is designated F-8.