Spring Stefan, Merkhoffer Birgit, Weiss Norbert, Kroppenstedt Reiner M, Hippe Hans, Stackebrandt Erko
DSMZ - Deutsche Sammlung von Mikroorganismen und Zellkulturen, Mascheroder Weg 1b, 38124 Braunschweig, Germany.
Int J Syst Evol Microbiol. 2003 Jul;53(Pt 4):1019-1029. doi: 10.1099/ijs.0.02554-0.
Taxonomic studies were performed on four strains (D-1/D-an/IIT, C/C-an/B1T, A-1/C-an/C1T and A-1/C-an/IT) of anaerobic, gram-positive, spore-forming bacteria originally isolated from a mat sample retrieved from a shallow, moated area around Lake Fryxell, an Antarctic freshwater lake. Phylogenetic analyses based on 16S rRNA gene sequence data indicated that these strains are affiliated with cluster I clostridia and form a coherent group with Clostridium estertheticum and Clostridium laramiense. Similarity values among 16S rRNA gene sequences within this assemblage ranged between 96.7 and 99.8%. Despite the close phylogenetic relationship, several distinguishing phenotypic traits were found among the novel strains using a polyphasic approach. All strains were psychrophilic, but the temperature optimum for growth differed markedly, ranging from 4 to 16 degrees C. In addition, substrate utilization patterns, fermentation end products, cellular fatty acid profiles and morphological traits enabled a clear differentiation between the strains. DNA-DNA hybridization experiments revealed that each of the four novel strains represents a distinct species, with DNA-DNA similarity values to related strains in the range 16-62%. In contrast, the type strains of C. estertheticum and C. laramiense shared 79% DNA-DNA similarity, indicating a close relationship at the species level. On the basis of genetic and phenotypic properties, it is proposed to designate four novel species of the genus Clostridium to harbour the newly isolated strains: Clostridium frigoris sp. nov. (type strain D-1/D-an/IIT=DSM 14204T=ATCC BMAA-579T), Clostridium lacusfryxellense sp. nov. (type strain C/C-an/B1T=DSM 14205T=ATCC BAA-580T), Clostridium bowmaniisp. nov. (type strain A-1/C-an/C1T=DSM 14206T=ATCC BAA-581T) and Clostridium psychrophilum sp. nov. (type strain A-1/C-an/IT=DSM 14207T=ATCC BAA-582T). It is also proposed to unite C. laramiense and C. estertheticum under C. estertheticum. The subspecies C. estertheticum subsp. laramiense subsp. nov. is established, represented by strain ATCC 51254T (=DSM 14884T). The type strain of C. estertheticum subsp. estertheticum remains NCIMB 12511T (=DSM 8809T).
对从南极淡水湖弗里克塞尔湖周边浅护城河区域采集的一块垫样中最初分离出的4株厌氧、革兰氏阳性、产芽孢细菌（菌株D-1/D-an/IIT、C/C-an/B1T、A-1/C-an/C1T和A-1/C-an/IT）进行了分类学研究。基于16S rRNA基因序列数据的系统发育分析表明，这些菌株隶属于梭菌属第一类群，与雅致梭菌（Clostridium estertheticum）和拉腊米梭菌（Clostridium laramiense）形成一个连贯的类群。该类群内16S rRNA基因序列间的相似性值在96.7%至99.8%之间。尽管亲缘关系密切，但采用多相分类法在这些新菌株中发现了几个显著的表型特征。所有菌株均为嗜冷菌，但生长的最适温度差异显著，范围为4至16℃。此外，底物利用模式、发酵终产物、细胞脂肪酸谱和形态特征使得这些菌株之间能够明显区分。DNA-DNA杂交实验表明，这4株新菌株各自代表一个独特的物种，与相关菌株的DNA-DNA相似性值在16%至62%之间。相比之下，雅致梭菌和拉腊米梭菌的模式菌株共享79%的DNA-DNA相似性，表明在种水平上关系密切。基于遗传和表型特性，建议指定梭菌属的4个新物种来容纳新分离的菌株：嗜冷梭菌（Clostridium frigoris）新种（模式菌株D-1/D-an/IIT = DSM 14204T = ATCC BMAA-579T）、弗里克塞尔湖梭菌（Clostridium lacusfryxellense）新种（模式菌株C/C-an/B1T = DSM 14205T = ATCC BAA-580T）、鲍曼氏梭菌（Clostridium bowmanii）新种（模式菌株A-1/C-an/C1T = DSM 14206T = ATCC BAA-581T）和嗜冷梭菌（Clostridium psychrophilum）新种（模式菌株A-1/C-an/IT = DSM 14207T = ATCC BAA-582T）。还建议将拉腊米梭菌和雅致梭菌归为雅致梭菌。建立了雅致梭菌拉腊米亚种（Clostridium estertheticum subsp. laramiense）新亚种，由菌株ATCC 51254T（= DSM 14884T）代表。雅致梭菌酯亚种的模式菌株仍为NCIMB 12511T（= DSM 8809T）。
