Bozal Núria, Montes Ma Jesus, Miñana-Galbis David, Manresa Angeles, Mercadé Elena
Laboratori de Microbiologia, Facultat de Farmacia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain.
Int J Syst Evol Microbiol. 2009 Feb;59(Pt 2):336-40. doi: 10.1099/ijs.0.000737-0.
Two strains of psychrotolerant bacteria, designated M7(T) and M5, isolated from Antarctic coastal marine environments were studied to determine their taxonomic position. The organisms comprised Gram-negative, rod-shaped, facultatively anaerobic cells that were motile by means of single polar flagella. Neither of the bacterial isolates had a requirement for Na(+). These two psychrotolerant strains grew at temperatures ranging from -4 to 30 degrees C. Both strains were capable of producing H(2)S from thiosulfate and were able to use sodium nitrate and trimethylamine N-oxide as terminal electron acceptors during anaerobic growth. 16S rRNA gene sequence analysis placed M7(T) and M5 within the genus Shewanella; the strains showed the highest similarity (99.9 and 99.2 % respectively) with respect to the type strains of Shewanella livingstonensis and Shewanella frigidimarina. However the levels of gyrB sequence similarity between strain M7(T) and the type strains of S. livingstonensis and S. frigidimarina were 87.6 and 87.4 %, respectively. DNA-DNA hybridization experiments performed between the Antarctic isolate M7(T) and S. livingstonensis LMG 19866(T) and S. frigidimarina LMG 19475(T) revealed levels of relatedness of 32 and 35 %, respectively. Strain M5 showed 100 % DNA relatedness with respect to strain M7(T). The DNA G+C content of these bacteria was 42 mol%. Several phenotypic characteristics, the cellular fatty acid compositions and the quinone content of strains M7(T) and M5 served to differentiate them from related shewanellae. On the basis of the data from this polyphasic taxonomic study, M7(T) and M5 constitute a single genospecies. They represent a novel species of the genus Shewanella, for which the name Shewanella vesiculosa sp. nov. is proposed. The type strain is M7(T) (=LMG 24424(T) =CECT 7339(T)).
对从南极沿海海洋环境中分离出的两株耐冷菌（分别命名为M7(T)和M5）进行了研究，以确定它们的分类地位。这些微生物由革兰氏阴性、杆状、兼性厌氧细胞组成，通过单根极鞭毛运动。这两株细菌均不需要Na(+)。这两株耐冷菌在-4至30℃的温度范围内生长。两株菌都能够从硫代硫酸盐产生H(2)S，并且在厌氧生长期间能够使用硝酸钠和三甲胺N-氧化物作为末端电子受体。16S rRNA基因序列分析将M7(T)和M5归入希瓦氏菌属；这两株菌与利文斯顿希瓦氏菌和嗜冷希瓦氏菌的模式菌株相似度最高（分别为99.9%和99.2%）。然而，菌株M7(T)与利文斯顿希瓦氏菌和嗜冷希瓦氏菌模式菌株之间的gyrB序列相似度分别为87.6%和87.4%。在南极分离株M7(T)与利文斯顿希瓦氏菌LMG 19866(T)和嗜冷希瓦氏菌LMG 19475(T)之间进行的DNA-DNA杂交实验表明，相关性水平分别为32%和35%。菌株M5与菌株M7(T)的DNA相关性为100%。这些细菌的DNA G+C含量为42 mol%。M7(T)和M5菌株的一些表型特征、细胞脂肪酸组成和醌含量有助于将它们与相关希瓦氏菌区分开来。基于这项多相分类研究的数据，M7(T)和M5构成一个单一的基因种。它们代表希瓦氏菌属的一个新物种，为此提出名称希瓦氏菌泡囊新种。模式菌株是M7(T)（=LMG 24424(T)=CECT 7339(T)）。
