Baer Marcie L, Ravel Jacques, Piñeiro Silvia A, Guether-Borg Diana, Williams Henry N
Department of Biomedical Sciences, University of Maryland at Baltimore, 666 W. Baltimore Street, Baltimore, MD 21201, USA.
Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 East Pratt Street, Baltimore, MD 21202, USA.
Int J Syst Evol Microbiol. 2004 Jul;54(Pt 4):1011-1016. doi: 10.1099/ijs.0.02458-0.
Bdellovibrios are unique, predatory bacteria with an intraperiplasmic growth and multiplication phase within their prey, which consists of many Gram-negative bacteria. Until recently, all bacteria that exhibited these traits were included in the genus Bdellovibrio. However, analysis of 16S rDNA sequences and other studies have demonstrated substantial genotypic, phenotypic and ecotypic diversity among the organisms in this genus (Baer et al., 2000; Snyder et al., 2002). This has resulted in reclassification of Bdellovibrio stolpii and Bdellovibrio starrii into the newly constructed genus Bacteriovorax (Baer et al., 2000). In this study, examination of marine isolates of Bdellovibrio (designated SJT, AQ and JS5T) has revealed them to be related more closely to the newly designated genus Bacteriovorax. Phylogenetic analysis of 16S rRNA gene sequences revealed that marine isolates SJT, AQ and JS5T clustered in a separate clade from Bdellovibrio bacteriovorus 100T as part of the clade that contains Bacteriovorax spp., indicating a much closer taxonomic relationship to the latter. DNA-DNA hybridization experiments also demonstrated <5 % similarity between Bdellovibrio bacteriovorus 100T and the marine isolates. Distinct differences between the salt-water group and Bdellovibrio spp. were also observed by determination of DNA G+C content, salinity growth testing and antibiotic sensitivity analysis. On the basis of the results from the studies described above, it is proposed that marine isolates SJT (=ATCC BAA-682T=DSM 15412T) and JS5T (=ATCC BAA-684T=DSM 15409T) should be classified within the genus Bacteriovorax as the type strains of Bacteriovorax marinus sp. nov. and Bacteriovorax litoralis sp. nov., respectively.
蛭弧菌是一类独特的捕食性细菌，它们在猎物（包括许多革兰氏阴性菌）的周质空间内经历生长和繁殖阶段。直到最近，所有表现出这些特征的细菌都被归入蛭弧菌属。然而，对16S rDNA序列的分析及其他研究表明，该属中的生物在基因型、表型和生态型上存在显著差异（Baer等人，2000年；Snyder等人，2002年）。这导致了斯托尔普蛭弧菌和斯塔尔蛭弧菌被重新分类到新建立的食菌蛭弧菌属（Baer等人，2000年）。在本研究中，对海洋来源的蛭弧菌分离株（命名为SJT、AQ和JS5T）的检测表明，它们与新指定的食菌蛭弧菌属关系更为密切。16S rRNA基因序列的系统发育分析显示，海洋分离株SJT、AQ和JS5T聚集在一个与食菌蛭弧菌100T不同的分支中，属于包含食菌蛭弧菌属物种的分支，这表明它们与后者的分类关系更为密切。DNA-DNA杂交实验也表明，食菌蛭弧菌100T与海洋分离株之间的相似性小于5%。通过测定DNA G+C含量以及盐度生长测试和抗生素敏感性分析，还观察到了海水组与蛭弧菌属之间的明显差异。基于上述研究结果，建议将海洋分离株SJT（=ATCC BAA-682T=DSM 15412T）和JS5T（=ATCC BAA-684T=DSM 15409T）分别作为海生食菌蛭弧菌新种和沿岸食菌蛭弧菌新种的模式菌株，归入食菌蛭弧菌属。
