嗜盐碱球菌湛江新种的系统分类鉴定(英文)

Natronococcus zhanjiangensis sp. nov., a halophilic archaeon isolated from a saltern sediment in Zhan Jiang,Guangdong Province,China

根据经典微生物划线纯培养方法从湛江一个盐田泥样中分离获得1个嗜盐碱古菌菌株SCSIOCD13T,通过形态、细胞化学分类及分子发育等对其进行系统分类鉴定研究。经鉴定该菌细胞球形,好氧,革兰染色不定,在最适pH 8.5和37℃培养条件下,能够耐受2.5～5.5 mol/L盐浓度生长。16S rRNA基因序列比对分析显示,该菌株与嗜盐碱古菌Natronococcus属成员N.jeotgali B1T(99.2%),N.occultus NCMB 2192T(96.8%)和N.amylolyticus Ah-36T(95.8%)最相近,且系统发育树和细胞化学特征与Natronococcus属相一致。然而,系统发育树上显示该菌株与最相似菌种形成单独分支,且生理学特性显示出与最相似的3个物种具有明显的差异,包括盐浓度、pH耐受,镁离子需求,H2S产生,淀粉、明胶水解,抗生素敏感性等。另外,杂交结果显示,菌株SCSIO CD13T与最相似菌种Natronococcus jeotgali B1T的杂交值为23%;综合多相分类结果,菌株SCSIO CD13T应为Natronococcus属的一个新成员,将其命名为湛江嗜盐碱球菌新种(Natronococcus zhanjian-gensis),典型菌株SCSIO CD13T。

A novel halophilic archaeon, strain CD13T, was isolated from sahern sediment of Zhan Jiang, Guangdong Province, China, by using classical spread plate method. And it was characterized on the basis of phenotypic, chemo- taxonomic and phylogenetic features. Results showed that the cells of strain CD13T, were aerobic, gram-variable and cocci. It could grow at 2.5 ~ 5.5 mol/L NaC1 with the optima of pH 8.5 and 37 ~C. Magnesium was not required for growth. Partial 16S rRNA gene sequence analysis showed that the isolate was closest to Natronococcus jeotgali B1T （99.2% , sequence similarity） , Natronococcus occultus NCMB 2192T （96.8%） and＂ Natronococcus amylolyticus Ah- 36T（95.8% ）. The constructed phylogenetic tree based on 16S rRNA gene sequences showed that t strain CD13T formed a distinct cluster with N.jeotgali B1T, N. occultus NCMB 2192T and N. amylolyticus Ah-36T. In addition, ehe- motaxonomic properties including polar lipids and menaquinones componentes are consistent with those of the genus Natronococcus. However, strain SCSIO CDI3T could be differentiated from its closest phylogenetic neighbours by phys- iological and chemical characteristics. Furthermore, DNA-DNA hybridization level between strain CD13T and its clo- sest phylogenetie neighbor Ncc jeotgali B1T was 23% , which was far below the 70% cut-off point. Based on the polyphasic taxonomic data, strain SCSIO CD13T represents a hitherto unknown species of the genus Natronococcus, for which the name Natronococcus zhaniiangensis sv. nov. was proposed. The type strain is SCSIO CD13T.