Süss Jacqueline, Herrmann Kerstin, Seidel Michael, Cypionka Heribert, Engelen Bert, Sass Henrik
Institut für Chemie und Biologie des Meeres, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.
Microb Ecol. 2008 Apr;55(3):371-83. doi: 10.1007/s00248-007-9282-6. Epub 2007 Sep 16.
Eastern Mediterranean sediments are characterized by the periodic occurrence of conspicuous, organic matter-rich sapropel layers. Phylogenetic analysis of a large culture collection isolated from these sediments revealed that about one third of the isolates belonged to the genus Photobacterium. In the present study, 22 of these strains were examined with respect to their phylogenetic and metabolic diversity. The strains belonged to two distinct Photobacterium populations (Mediterranean cluster I and II). Strains of cluster I were isolated almost exclusively from organic-rich sapropel layers and were closely affiliated with P. aplysiae (based on their 16S rRNA gene sequences). They possessed almost identical Enterobacterial Repetitive Intergenic Consensus (ERIC) and substrate utilization patterns, even among strains from different sampling sites or from layers differing up to 100,000 years in age. Strains of cluster II originated from sapropels and from the surface and carbon-lean intermediate layers. They were related to Photobacterium frigidiphilum but differed significantly in their fingerprint patterns and substrate spectra, even when these strains were obtained from the same sampling site and layer. Temperature range for growth (4 to 33 degrees C), salinity tolerance (5 to 100 per thousand), pH requirements (5.5-9.3), and the composition of polar membrane lipids were similar for both clusters. All strains grew by fermentation (glucose, organic acids) and all but five by anaerobic respiration (nitrate, dimethyl sulfoxide, anthraquinone disulfonate, or humic acids). These results indicate that the genus Photobacterium forms subsurface populations well adapted to life in the deep biosphere.
东地中海沉积物的特征是周期性出现明显的、富含有机物的腐殖质层。对从这些沉积物中分离出的大量培养物进行系统发育分析表明，约三分之一的分离物属于发光杆菌属。在本研究中，对其中22株菌株的系统发育和代谢多样性进行了检测。这些菌株属于两个不同的发光杆菌种群（地中海簇I和II）。簇I的菌株几乎完全从富含有机物的腐殖质层中分离出来，并且与海兔发光杆菌密切相关（基于它们的16S rRNA基因序列）。即使在来自不同采样地点或年龄相差达10万年的层的菌株之间，它们也具有几乎相同的肠杆菌重复基因间共有序列（ERIC）和底物利用模式。簇II的菌株源自腐殖质层以及表层和贫碳中间层。它们与嗜冷发光杆菌相关，但即使这些菌株来自相同的采样地点和层，它们在指纹图谱和底物谱方面也有显著差异。两个簇的生长温度范围（4至33摄氏度）、耐盐性（5至千分之一百）、pH要求（5.5 - 9.3）以及极性膜脂的组成相似。所有菌株都通过发酵（葡萄糖、有机酸）生长，除了五株外所有菌株都通过厌氧呼吸（硝酸盐、二甲基亚砜、蒽醌二磺酸盐或腐殖酸）生长。这些结果表明，发光杆菌属形成了适应深层生物圈生活的地下种群。
