Methanosarcina Genomics

该项目将利用最近完成的醋酸甲烷八叠球菌的基因组序列来确定两个关键生理过程的新基因/蛋白。将采用功能基因组学方法进一步了解(I)乙酸乙酯发酵为甲烷(全球甲烷产量的三分之二是通过该途径产生的)，以及(Ii)醋酸菌和古生菌对环境胁迫的反应。被测序的微生物基因组的很大比例的开放读框与任何已知蛋白质没有显著的推论一致性；因此，预计将发现新的蛋白质和酶，它们的特征将揭示新的生化原理。全基因组DNA微阵列和双向凝胶电泳法将被用来识别在醋酸盐、甲醇或甲胺以及在高盐和低盐的介质中生长过程中差异表达的基因。这些结果有望(I)确定乙酸盐形成甲烷的特定基因，以及(Ii)揭示古生菌适应不断变化的环境条件的一般原理。差异表达的基因将通过转录图谱进行表征，并将分析基因序列以获取有关其潜在功能的信息。将进行基因敲除实验，以验证它们在醋酸盐发酵途径或渗透胁迫中的作用，并帮助确定它们的特定功能。通过更详细地阐明生理过程，该项目有望通过揭示乙酸杆菌如何对变化的环境条件做出反应，以及它如何与构成全球碳循环中厌氧环节的微生物群落中的其他成员相互作用，从而增加对生物复杂性的理解。此外，来自每个学术机构的学生将接触到来自每个合作学术机构的各种实验途径和方法。研究的基本互动性将为参与研究的学生提供广泛的遗传学、基因组学、发酵、微生物生理学和酶特性的接触。这种广泛的培训旨在为未来的研究提供人员，这些研究将基于未来十年乃至更长时间内预期的过多基因组信息。

This project will exploit the recently completed genomic sequence of Methanosarcina acetivorans to identify novel genes/proteins for two key physiological processes. A functional genomics approach will be taken to further the understanding of (i) the fermentation of acetate to methane (the pathway by which two-thirds of the global output of methane is produced) by M. acetivorans, and (ii) the response to environmental stress by M. acetivorans and the Archaea in general. A large percentage of the open reading frames of sequenced microbial genomes have no significant deduced identity to any known proteins; thus it is expected that novel proteins and enzymes will be discovered and that their characterization will uncover new biochemical principles. Whole genome DNA microarray and two-dimensional gel electrophoresis methods will be employed to identify genes that are differentially expressed during growth on acetate versus methanol or methylamines, and in media containing high and low salt. The results are expected to (i) identify genes specific for methane formation from acetate and (ii) uncover general principles of Archaeal adaptation to changing environmental conditions. The differentially expressed genes will be characterized by transcriptional mapping and the gene sequences will be analyzed for information regarding their potential function. Gene knockout experiments will be performed to validate their role in the acetate fermentation pathway or osmotic stress, and also to aid in the determination of their specific function. Selected genes will be over-expressed and the gene products characterized to determine their biochemical properties and specific physiological functionBy elucidating physiological processes in greater detail, the project is expected to increase the understanding of biocomplexity by revealing how M. acetivorans reacts to changing environmental conditions and how it interacts with other members in microbial consortia that comprise the anaerobic link in the global carbon cycle. In addition, students from each academic institution will be exposed to a wide variety of experimental approaches and methods from each of the collaborating academic institutions . The fundamental interactive nature of the research will provide participating students with broad exposure to genetics, genomics, fermentation, microbial physiology, and enzyme characterization. This type of broad training is designed to provide personnel for future research that will be based on the plethora of genomic information expected in the next decade and beyond