Institute for Limnology, Austrian Academy of Sciences, Mondseestrasse 9, A-5310 Mondsee, Austria.
Institute of Hydroecology and Ichthyology of Scientific Centre of Zoology and Hydroeocology of National Academy of Sciences of Republic of Armenia, St Paruyr Sevak 7, 0014 Yerevan, Armenia.
Int J Syst Evol Microbiol. 2012 Feb;62(Pt 2):376-383. doi: 10.1099/ijs.0.031393-0. Epub 2011 Mar 25.
Strain AM-8B5(T), isolated from Lake Sevan in Armenia, was characterized phenotypically, chemotaxonomically and phylogenetically. This chemo-organoheterotrophic, aerobic, facultatively anaerobic, catalase- and oxidase-positive, non-motile strain grew on NSY medium at NaCl concentrations of 0.0-0.2 % (w/v) and at 4-30 °C. Whole-cell fatty acids were dominated by summed feature 3 (including C(16 : 1)ω7c and iso-C(15 : 0) 2-OH), C(16 : 0) and C(18 : 1)ω7c. C(12 : 0) 2-OH and C(16 : 1) 2-OH were the only hydroxylated fatty acids detected. Phylogenetic analysis as well as phenotypic and chemotaxonomic similarities indicated that the novel isolate was affiliated with the genus Polynucleobacter. 16S rRNA gene similarity values with the four previously described Polynucleobacter species ranged from 96.2 to 98.7 %. DNA-DNA hybridization experiments showed that the isolate did not belong to any of the previously described Polynucleobacter species. The isolate could be distinguished from all previously established Polynucleobacter species based on chemotaxonomic and phenotypic traits. The bacterium possessed a free-living lifestyle and represents a group of bacteria inhabiting the water column of many freshwater lakes. Based on the revealed phylogeny, and chemotaxonomic and phenotypic differences to previously described Polynucleobacter species, it is proposed that the isolate represents a novel species, Polynucleobacter difficilis sp. nov.; the type strain is AM-8B5(T) ( = DSM 22349(T) = CIP 110078(T)).
从亚美尼亚塞凡湖分离到的 AM-8B5(T)菌株，在表型、化学分类学和系统发育方面进行了特征描述。该化学异养、需氧、兼性厌氧、过氧化氢酶和氧化酶阳性、非运动菌株可在 NSY 培养基中生长，NaCl 浓度为 0.0-0.2%（w/v），温度为 4-30°C。细胞脂肪酸主要由特征脂肪酸 3（包括 C(16：1)ω7c 和 iso-C(15：0) 2-OH）、C(16：0) 和 C(18：1)ω7c 组成。检测到的唯一羟基脂肪酸是 C(12：0) 2-OH 和 C(16：1) 2-OH。系统发育分析以及表型和化学分类学相似性表明，新分离株与 Polynucleobacter 属有关。16S rRNA 基因与先前描述的四种 Polynucleobacter 种的相似性值为 96.2-98.7%。DNA-DNA 杂交实验表明，该分离株不属于任何先前描述的 Polynucleobacter 种。该分离株可根据化学分类学和表型特征与所有先前建立的 Polynucleobacter 种区分开来。该细菌具有自由生活的生活方式，代表了栖息在许多淡水湖水柱中的细菌群体。基于揭示的系统发育以及与先前描述的 Polynucleobacter 种的化学分类学和表型差异，建议该分离株代表一个新的物种，即 Polynucleobacter difficilis sp. nov.；其模式菌株为 AM-8B5(T)（=DSM 22349(T)=CIP 110078(T)）。
