Prabahar Vadivel, Dube Smita, Reddy G S N, Shivaji S
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India.
Syst Appl Microbiol. 2004 Feb;27(1):66-71. doi: 10.1078/0723-2020-00249.
Strain DVS 5a1 was isolated from a moraine sample from the McMurdo Dry Valleys region of Antarctica. The strain is aerobic, Gram-positive, with white aerial mycelia and brown substrate mycelia, sporulating, has meso-diaminopimelic acid, arabinose and galactose in the cell wall, MK-8 (H4) as the major menaquinone and a mol% G+C content of DNA of 71% thus confirming to the description of the genus Pseudonocardia. Phylogenetic analysis based on the 16S rRNA gene sequence analysis further confirms that DVS 5al which forms a robust clade with P. alni, P. compacta, P. autotrophica and P. kongjuensis is closely related to the genus Pseudonocardia and exhibits maximum similarity of 99.7% with Pseudonocardia alni. However, at whole genome level as determined by DNA-DNA hybridisation DVS 5al exhibits a similarity of only 50% with Pseudonocardia alni. Further, DVS 5al differs from Pseudonocardia alni in that it does not produce acid from D-arabinose, meso-erythritol, melizitose, sorbitol, sucrose, D-trehalose; but produces acid from D-mannitol, D-galactose, D-maltose, D-mannose, inulin, D-ribose and D-xylose. Further, compared to Pseudonocardia alni, it has two additional fatty acids namely Me-C(18:0) and Me-C(19:0) and also possesses one additional unidentified lipid. It also shows distinct differences with P. compacta, P. autotrophica and P. kongjuensis and the other species of Pseudonocardia. It is proposed to assign DVS 5a1 the status of a new species for which the name Pseudonocardia antarctica sp. nov. is suggested.
菌株DVS 5a1是从南极洲麦克默多干谷地区的冰碛样本中分离出来的。该菌株为需氧菌，革兰氏阳性，有白色气生菌丝体和棕色基内菌丝体，可形成孢子，细胞壁中含有内消旋二氨基庚二酸、阿拉伯糖和半乳糖，以MK-8（H4）作为主要甲基萘醌，DNA的鸟嘌呤与胞嘧啶含量为71mol%，因此符合假诺卡氏菌属的描述。基于16S rRNA基因序列分析的系统发育分析进一步证实，与桤木假诺卡氏菌、紧密假诺卡氏菌、自养假诺卡氏菌和孔州假诺卡氏菌形成一个稳健分支的DVS 5a1与假诺卡氏菌属密切相关，与桤木假诺卡氏菌的最大相似度为99.7%。然而，通过DNA-DNA杂交测定，在全基因组水平上，DVS 5a1与桤木假诺卡氏菌的相似度仅为50%。此外，DVS 5a1与桤木假诺卡氏菌的不同之处在于，它不能利用D-阿拉伯糖、内消旋赤藓醇、蜜二糖、山梨醇、蔗糖、D-海藻糖产酸；但能利用D-甘露醇、D-半乳糖、D-麦芽糖、D-甘露糖、菊粉、D-核糖和D-木糖产酸。此外，与桤木假诺卡氏菌相比，它还有另外两种脂肪酸，即甲基-支链脂肪酸（Me-C(18:0)）和甲基-支链脂肪酸（Me-C(19:0)），并且还拥有一种额外的未鉴定脂质。它与紧密假诺卡氏菌、自养假诺卡氏菌、孔州假诺卡氏菌以及假诺卡氏菌属的其他物种也表现出明显差异。建议将DVS 5a1指定为一个新物种，命名为南极假诺卡氏菌（Pseudonocardia antarctica sp. nov.）。
