Widespread distribution and high abundance of Rhizobium radiobacter within Mediterranean subsurface sediments.
Widespread distribution and high abundance of Rhizobium radiobacter within Mediterranean subsurface sediments.
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地中海地下沉积物中放射根瘤菌分布广泛且丰度高。
DOI：
10.1111/j.1462-2920.2006.01058.x
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发表时间：
2006
影响因子：
5.1
通讯作者：
B. Engelen
中科院分区：
文献类型：
--
作者：
J. Süss;K. Schubert;H. Sass;H. Cypionka;J. Overmann;B. Engelen
东地中海沉积物的特点是出现独特的，富含有机物的层，称为腐泥。与邻近的贫碳中间层相比，这些港湾的微生物数量增加。最近从这些沉积物中获得的培养物收集物由20%的菌株组成，这些菌株与以前被归类为根癌农杆菌的辐射根瘤菌密切相关。为了证实和定量R的原位丰度。在放射免疫法中，开发了高度特异性的定量聚合酶链反应（PCR）方案。为了将定量结果转化为细胞数，测定每个基因组的rrn操纵子的拷贝数。Southern杂交结果表明，我们的分离物含有四个操纵子。最后，定量PCR应用于45沉积物样品获得整个东地中海。辐射根瘤菌存在于45个样品中的38个，表明几乎无处不在的分布。总共检测到25-40 000个细胞/克沉淀物，相当于0.001-5.1%的细菌细胞。一般来说，R.放射性随深度增加而增加，腐泥中放射性高于中间层。这表明R.放射性生物在20万年前的腐泥中形成了一个活跃的种群。本研究首次表明，在这种环境中培养的地下细菌非常丰富。
Eastern Mediterranean sediments are characterized by the occurrence of distinct, organic-rich layers, called sapropels. These harbour elevated microbial numbers in comparison with adjacent carbon-lean intermediate layers. A recently obtained culture collection from these sediments was composed of 20% of strains closely related to Rhizobium radiobacter, formerly classified as Agrobacterium tumefaciens. To prove and quantify the in situ abundance of R. radiobacter, a highly specific quantitative polymerase chain reaction (PCR) protocol was developed. To convert quantification results into cell numbers, the copy number of rrn operons per genome was determined. Southern hybridization showed that our isolates contained four operons. Finally, quantitative PCR was applied to 45 sediment samples obtained across the eastern Mediterranean. Rhizobium radiobacter was present in 38 of 45 samples indicating an almost ubiquitous distribution. In total, 25-40 000 cells per gram of sediment were detected, corresponding to 0.001-5.1% of the bacterial cells. In general, the relative and absolute abundance of R. radiobacter increased with depth and was higher in sapropels than in intermediate layers. This indicates that R. radiobacter forms an active population in up to 200 000 years old sapropels. The present study shows for the first time that a cultivated subsurface bacterium is highly abundant in this environment.
影响因子：
5.1
作者：
Alavi, M;Miller, T;Belas, R
通讯作者：
Belas, R