Mechanisms for Growth of Sulfate-Reducing Bacteria under Syntrophic Conditions

厌氧环境分布在整个地球上，氢气总是作为有机化合物分解的中间产物存在。在自然条件下，某些能够消耗H2的厌氧细菌将H2浓度维持在阈值水平(硫酸盐还原环境中为1-2 NM)。环境微生物学家对氢气消耗的生理学很感兴趣，因为这一过程具有全球意义。然而，在基因水平上研究这一点的能力是最近才出现的。科学家们现在准备解决硫酸盐还原细菌在自然条件下生长的机制问题。将以脱硫弧菌G20作为模式生物。初步实验将包括筛选菌株G20的5760个转座子突变体文库，以了解其在H2上与苯甲酸消耗H2的细菌Syntrous acidrophicus一起生长的能力。该筛选过程使用对签名标记突变过程的修改。不能在合养生长过程中产生的H2上生长的突变株(在共培养中)将被鉴定以确定发生突变的基因。我们预测，我们将通过这种方式识别10-20个功能和调节基因。功能基因将通过比较突变体之间的氢气消耗动力学来表征，以确定这些蛋白质是否直接参与氢气加工。更广泛的影响包括使用新的方法进行本科生学习。此外，这些研究的结果可以提供有用的信息，以帮助开发用于生产或消费氢气的生物过程。

Anaerobic environments are distributed over the entire earth and H2 is always present as an intermediate in the decomposition of organic compounds. Under natural conditions, certain anaerobic bacteria capable of H2 consumption, maintain the H2 concentration at threshold levels (1-2 nM for sulfate reducing environments). The physiology of H2 consumption is of interest to environmental microbiologists because of the global significance of this process. However, the ability to study this at the genetic level has only recently emerged. Scientists are now poised to address the question of the mechanism for growth of sulfate reducing bacteria under natural conditions. Desulfovibrio desulfuricans G20 will be used as the model organism. Initial experiments will involve screening a library of 5760 transposon mutants of strain G20 for the ability to grow on H2 together with the benzoate-consuming-H2 producing bacterium Syntrophus aciditrophicus. The screening process uses a modification of the signature tagged mutagenesis procedure. Mutants unable to grow on the H2 produced during syntrophic growth (within the coculture) will be characterized to determine the gene that has been mutated. We predict that we will identify 10-20 functional and regulatory genes in this way. Functional genes will be characterized by comparing the kinetics of H2 consumption among the mutants in order to determine whether these proteins are involved directly in H2 processing. Broader impacts include the use of novel approaches to undergraduate learning. As well, results of these studies could provide useful information to aid in development of biological processes for H2 production or consumption.