Rusch Antje, Amend Jan P
Department of Earth and Planetary Sciences, Washington University, One Brookings Drive, St. Louis, MO 63130, USA.
Microb Ecol. 2008 May;55(4):723-36. doi: 10.1007/s00248-007-9315-1.
The microbial population of geothermally heated sediments in a shallow bay of Vulcano Island (Italy) was characterized with respect to metabolic activities and the putatively catalyzing hyperthermophiles. Site-specific anoxic culturing media, most of which were amended with combinations of electron donors (glucose or carboxylic acids) and acceptors (sulfate), were used for selective enrichment of metabolically defined subpopulations. The mostly archaeal chemoautotrophs produced formate at rates of 3.25 and 0.46 fmol cell(-1) day(-1) with and without sulfate, respectively. The glucose fermenting heterotrophs produced acetate (18 fmol cell(-1) day(-1)) and lactate (2.6 fmol cell(-1) day(-1)) and were identified as predominantly Thermus sp. and coccoid archaea. These archaeal cells also metabolized lactate (5.6 fmol cell(-1) day(-1)), but neither formate nor acetate. The heterotrophic culture enriched on formate/ acetate/propionate/sulfate utilized mainly formate (27 fmol cell(-1) day(-1)) and lactate (89-195 fmol cell(-1) day(-1)), and consumed sulfate (38-68 fmol cell(-1) day(-1)). These formate or lactate consuming sulfate reducers were dominated by Archaeoglobales (7% in situ) and unidentified Archaea. The in situ benthic community comprised 15% Crenarchaeota, a significant group only in the autotrophic cultures, and 3% Thermus sp., the putatively predominant group involved in fermentative metabolism. The role of Thermoccales (4% in situ) remained undisclosed in our experiments. This first comprehensive data set established plausible links between several groups of hyperthermophiles in shallow marine hydrothermal systems, their metabolic function within the benthic microbial community, and biogeochemical turnover rates.
对意大利武尔卡诺岛一个浅湾中地热加热沉积物的微生物群落，就其代谢活动和推测起催化作用的嗜热菌进行了表征。使用特定地点的缺氧培养基，其中大部分添加了电子供体（葡萄糖或羧酸）和受体（硫酸盐）的组合，用于选择性富集代谢定义的亚群。大多数为古菌的化学自养菌在有硫酸盐和无硫酸盐的情况下，产甲酸的速率分别为3.25和0.46飞摩尔细胞⁻¹天⁻¹。发酵葡萄糖的异养菌产生乙酸盐（18飞摩尔细胞⁻¹天⁻¹）和乳酸盐（2.6飞摩尔细胞⁻¹天⁻¹），主要鉴定为嗜热栖热菌属和球状古菌。这些古菌细胞也代谢乳酸盐（5.6飞摩尔细胞⁻¹天⁻¹），但既不代谢甲酸盐也不代谢乙酸盐。在甲酸盐/乙酸盐/丙酸盐/硫酸盐上富集的异养培养物主要利用甲酸盐（27飞摩尔细胞⁻¹天⁻¹）和乳酸盐（89 - 195飞摩尔细胞⁻¹天⁻¹），并消耗硫酸盐（38 - 68飞摩尔细胞⁻¹天⁻¹）。这些消耗甲酸盐或乳酸盐的硫酸盐还原菌以古生球菌目（原位占7%）和未鉴定的古菌为主。原位底栖生物群落包括15%的泉古菌门，这是仅在自养培养物中显著的一个类群，以及3%的嗜热栖热菌属，这是推测参与发酵代谢的主要类群。在我们的实验中，栖热菌目（原位占4%）的作用仍未明确。这组首个全面的数据集在浅海热液系统中的几组嗜热菌、它们在底栖微生物群落中的代谢功能以及生物地球化学周转率之间建立了合理的联系。
