Potential for quantifying expression of the Geobacteraceae citrate synthase gene to assess the activity of Geobacteraceae in the subsurface and on current-harvesting electrodes
Potential for quantifying expression of the Geobacteraceae citrate synthase gene to assess the activity of Geobacteraceae in the subsurface and on current-harvesting electrodes
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DOI：
10.1128/aem.71.11.6870-6877.2005
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发表时间：
2005-11-01
影响因子：
4.4
通讯作者：
Lovley, DR
中科院分区：
文献类型：
--
作者：
Holmes, DE;Nevin, KP;Lovley, DR
土杆菌科柠檬酸合酶在遗传上与其他原核生物不同，是土杆菌科代谢中心的关键酶。因此，在纯培养研究和四种不同的土杆菌科占主导地位的环境中，评估了使用柠檬酸合酶mRNA水平来估计Geolectin代谢率的潜力。用从在以Fe（III）作为电子受体的恒化器中或以电极作为电子受体的分批中生长的Geetylsulfurreducens培养物中提取的mRNA进行的定量逆转录-PCR研究表明，柠檬酸合酶基因gltA的转录水平随着生长/Fe（III）减少或电流产生速率的增加而增加，而组成型表达的管家基因recA、rpoD、而proC保持相对恒定。从地下水中收集的U（VI）污染的网站进行原位铀生物修复提取的mRNA的分析显示，在地下水中的乙酸水平和gltA的成绩单水平之间的显着的对应关系。gltA的表达也显着更大的RNA提取地下水下的公路径流补给池，暴露于钙镁醋酸盐在6月，当醋酸盐浓度高，比在10月，当水平显着下降。它也可以检测gltA转录电流收集阳极部署在淡水沉积物。这些结果表明，它是可能的，通过跟踪柠檬酸合酶基因的表达监测原位代谢率的土杆菌科。
The Geobacteraceae citrate synthase is phylogenetically distinct from those of other prokaryotes and is a key enzyme in the central metabolism of Geobacteraceae. Therefore, the potential for using levels of citrate synthase mRNA to estimate rates of Geobacter metabolism was evaluated in pure culture studies and in four different Geobacteraceae-dominated environments. Quantitative reverse transcription-PCR studies with mRNA extracted from cultures of Geobacter sulfurreducens grown in chemostats with Fe(III) as the electron acceptor or in batch with electrodes as the electron acceptor indicated that transcript levels of the citrate synthase gene, gltA, increased with increased rates of growth/Fe(III) reduction or current production, whereas the expression of the constitutively expressed housekeeping genes recA, rpoD, and proC remained relatively constant. Analysis of mRNA extracted from groundwater collected from a U(VI)-contaminated site undergoing in situ uranium bioremediation revealed a remarkable correspondence between acetate levels in the groundwater and levels of transcripts of gltA. The expression of gltA was also significantly greater in RNA extracted from groundwater beneath a highway runoff recharge pool that was exposed to calcium magnesium acetate in June, when acetate concentrations were high, than in October, when the levels had significantly decreased. It was also possible to detect gltA transcripts on current-harvesting anodes deployed in freshwater sediments. These results suggest that it is possible to monitor the in situ metabolic rate of Geobacteraceae by tracking the expression of the citrate synthase gene.