Ecophysiology of Vacuolate Marine Sulfur Bacteria

液泡海洋硫细菌的生态生理学

• 批准号: 0526653
• 负责人: Douglas Nelson
• 金额: $ 39.29万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0526653&HistoricalAwards=false
• 关键词: Ecophysiology; Vacuolate; Marine; Sulfur; Bacteria

Large, vacuolate, nitrate-accumulating bacteria such as Beggiatoa can oxidize a majority of the sulfide produced in a variety of marine niches. Closely related sulfur bacteria (vacuolated attached filaments or VAF) that do not accumulate nitrate are abundant on surfaces at marine sulfidic vents. Collectively, these phylogenetically coherent organisms are the only Proteobacteria known to contain vacuoles and it is clear that they play a significant role in the nitrogen and sulfur cycles of a variety of marine environments. Beggiatoa species are also members of the bacterial consortium known as "black band disease" that constitutes a widespread and lethal disease of corals. The principal investigator has isolated a stable culture of a 7-micron diameter vacuolate Beggiatoa from black band disease (strain BBD) that accumulates nitrate and seems to be capable of dinitrogen fixation. This cultured strain and a number of natural populations of VAF and nitrate-accumulating Beggiatoa are the focus of this project. The investigator will use microelectrode and molecular analyses to understand the relative importance of nitrate- vs. oxygen-based respiration of sulfide in subgroups of vacuolate sulfur bacteria. The investigator will survey the vertical distribution and abundance of vacuolate Beggiatoa spp. and determine how vacuolar nitrate affects nitrogen fixation, and will derive and use probes of important nitrogen cycle genes (nifD, nifH and a nrfA homologue). In addition to training a graduate student, the project will specifically target disadvantaged and underrepresented undergraduates through interaction with the Biology Undergraduate Scholars Program at UC-Davis.

大型的、空泡状的、硝酸盐积累细菌，如贝贾托菌，可以氧化各种海洋生态位中产生的大部分硫化物。 不积累硝酸盐的密切相关的硫细菌（空泡附着细丝或VAF）在海洋硫化物喷口的表面上很丰富。总的来说，这些遗传上连贯的生物体是已知的唯一含有液泡的变形菌门，很明显，它们在各种海洋环境的氮和硫循环中发挥着重要作用。贝贾托物种也是被称为“黑带病”的细菌群落的成员，这种细菌群落构成了珊瑚的一种广泛和致命的疾病。主要研究者从积累硝酸盐的黑带病（BBD株）中分离出一种直径为7微米的空泡状贝氏菌的稳定培养物，该菌似乎能够固定二氮。该培养菌株和一些VAF和硝酸盐积累Beggiatoa的自然种群是该项目的重点。研究人员将使用微电极和分子分析来了解空泡硫细菌亚群中硫化物的硝酸盐呼吸与氧呼吸的相对重要性。调查人员将调查空泡贝氏菌属的垂直分布和丰度。并确定液泡硝酸盐如何影响固氮，并将获得和使用重要的氮循环基因（nifD，nifH和nrfA同源物）的探针。除了培养研究生外，该项目还将通过与加州大学戴维斯分校生物学本科生学者项目的互动，专门针对弱势和代表性不足的本科生。