Desulfofrigus sp. prevails in sulfate-reducing dilution cultures from sediments of the Benguela upwelling area.
Desulfofrigus sp. prevails in sulfate-reducing dilution cultures from sediments of the Benguela upwelling area.
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DOI：
10.1111/1574-6941.12039
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发表时间：
2013-04
影响因子：
4.2
通讯作者：
B. Kraft;B. Engelen;T. Goldhammer;Yu‐Shih Lin;H. Cypionka;M. Könneke
中科院分区：
文献类型：
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作者：
B. Kraft;B. Engelen;T. Goldhammer;Yu‐Shih Lin;H. Cypionka;M. Könneke
沿海上升流区域的沉积物通常以有机碳含量高为特征，主要通过厌氧微生物过程降解，包括硫酸盐还原作为主要的最终氧化步骤。尽管硫酸盐还原在这些沉积物中非常重要，但硫酸盐还原菌（SRB）的身份仍然几乎未知。在这里，我们采用基于培养的方法，利用选择性富集条件，研究沿着垂直于纳米比亚海岸大陆坡的横断面沉积物中活性SRB的多样性和分布（流星巡航M76/1）。为了促进最丰富的 SRB 的生长，制备了稀释系列并用氢气、乙酸盐或代表 SRB 典型底物的单体混合物进行了修正。在所有电子供体存在的情况下以及从 4 m 深的沉积物中都可以检测到 SRB 的生长。基于16S rRNA基因的DGGE分析和测序揭示了SRB与嗜冷菌相关的优势，特别是Desulfofrigus属，占微生物群落总数的1%，绝对丰度高达4.8×10(7)个细胞mL(-1)。一般来说，培养的 SRB 丰度随深度和不同采样点之间的变化而变化，并与先前报道的有机碳含量相关。化学营养型SRB在相对较高的稀释步骤中的生长以及产甲烷菌和产乙酸菌在较深沉积物中的富集表明本格拉上升流区域深层沉积物中利用氢的微生物过程及其生物地球化学意义之间的竞争。
Sediments of coastal upwelling areas are generally characterized by a high content of organic carbon that is mainly degraded via anaerobic microbial processes including sulfate reduction as a major terminal oxidation step. Despite the high importance of sulfate reduction in these sediments, the identity of sulfate-reducing bacteria (SRB) has remained almost unknown. Here, we applied a cultivation-based approach using selective enrichment conditions to study the diversity and distribution of active SRB in sediments along a transect perpendicular to the continental slope off the coast of Namibia (Meteor-cruise M76/1). To promote growth of the most abundant SRB, dilution series were prepared and amended with hydrogen, acetate, or a mixture of monomers representing typical substrates for SRB. Growth of SRB could be detected in the presence of all electron donors and from sediment down to 4 m depth. 16S rRNA gene-based DGGE analysis and sequencing revealed the predominance of SRB related to psychrophiles in particular to the genus Desulfofrigus, which made up 1 % of the total microbial community, accounting for an absolute abundance of up to 4.8 × 10(7) cells mL(-1) . In general, the abundance of cultured SRB changed with depth and between the different sampling sites and correlated with the content of organic carbon as previously reported. Growth of chemolithotrophic SRB in relatively high dilution steps and the enrichment of methanogens as well as acetogens from deeper sediment point to a competition between hydrogen-utilizing microbial processes and their biogeochemical significance in deep sediment layers of the Benguela upwelling area.