Biofilm Population Structure in the Gangetic Delta

恒河三角洲生物膜种群结构

• 批准号: 6998932
• 负责人: Gary K Schoolnik
• 金额: $ 3.24万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-15 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6998932
• 关键词: Bangladesh; Crustacea; Vibrio cholerae; biofilm; carbonates; cell population study; chitin; fluorescent in situ hybridization; invertebrate cuticle; microorganism metabolism; molecular probes; nucleic acid sequence; oligonucleotides; plastics; polymerase chain reaction; seasons; water environment; water microbiology

DESCRIPTION (provided by applicant) The research project summarized below, a collaboration between Drs. Schoolnik and Md. Sirajul Islam, will be performed mainly in Bangladesh at the International Center for Diarrhoeal Diseases Research (ICDDR,B) as an extension of NIH grant RO1 AI43422. Observational field studies performed in Bangladesh and elsewhere indicate that Vibrio cholerae, the agent of Asiatic cholera, is a normal member of natural aquatic habitats. In the rivers and estuaries that compose the Gangetic Delta, V. cholerae is believed to be associated with phyto- and zoo- plankton and to reside in mixed-species biofilms on a variety of surfaces. One such surface, the chitinous exoskeletons of copepods, can be degraded by V. cholerae chitinases, thus providing a source of nitrogen, carbon and energy. Other surfaces, including sand particles in the benthic layer of the estuary, are nutrient-poor. Biofilm bacteria on non-nutritive surfaces of this kind must obtain nutrients from the water column. In turn, the nutrient content and chemical features of the water column are dramatically affected by the monsoon seasonal cycle. As a result, the movement of V. cholerae between these sites in its aquatic reservoir and the human host is believed to be determined, in part, by the effects of the monsoon climate on the physicochemical features of this habitat. To begin to understand how these seasonal changes affect V. cholerae- containing mixed-species biofilms in the Ganges Delta, Drs. Islam and Schoolnik recently completed a one year pilot study (supported as a supplement to the parent grant) that showed the following: (1) V. cholerae resides in mixed species biofilms that form on non-nutritive plastic surfaces submerged in the Ganges Delta near Matlab, Bangladesh; and (2), the species composition of the biofilm changes during the year. These observations and the importance and abundance of chitin as a nutritive surface led to the following hypothesis: the population structure of V. cholerae-containing mixed-species biofilms varies as a function of the surface substratum (chitin compared to non-nutritive surfaces) and season (pre-monsoon, monsoon or post-monsoon). To test this hypothesis, the work proposed here will .use a culture-independent, 16S rRNA sequence-based method to determine the population structure of biofilm consortia on chitin or polycarbonate surfaces submerged at the Matlab sampling site during the pre-monsoon, monsoon .and post-monsoon periods. The identified species-specific sequences will then be used to design labeled pligonucleotide probes for fluorescence in situ hybridization (FISH) assays; these probes will be used in the last two years of the project to determine the population structure of monthly biofilm samples from chitin and polycarbonate surfaces. These results will be correlated with changes in water chemistry and cholera case rates. The transfer of each component of these key molecular ecology methods to the ICDDR,B--achieved by a training program for Bangladeshi scientists at the ICDDR,B and at Stanford--will significantly enhance the research capacity of this important Center.

描述（由申请人提供） 下面的研究项目总结了DRS之间的合作。 Schoolnik andMd。SirajulIslam将主要在孟加拉国举行，以延长NIH Grant RO1 AI43422的延伸，在孟加拉国国际腹泻疾病研究中心（ICDDR，b）进行。在孟加拉国和其他地方进行的观察性野外研究表明，亚洲霍乱的毒蛇弧菌是天然水生栖息地的正常成员。在构成恒河三角洲的河流和河口中，霍乱弧菌被认为与植物和动物群有关，并驻留在多种表面上的混合物种生物膜中。一种这样的表面，即copepods的几丁质外骨骼，可以被霍乱念珠菌酶降解，从而提供氮，碳和能量的来源。其他表面，包括河口底栖层中的砂颗粒，是营养贫困的。这种类型的非营养表面上的生物膜细菌必须从水柱中获得营养。反过来，水柱的养分含量和化学特征受到季风季节周期的极大影响。结果，据信，这些地点在其水生储层中的这些地点与人类宿主之间的运动部分通过季风气候对该栖息地的物理化学特征的影响确定。为了开始了解这些季节性变化如何影响哥伦比亚葡萄球菌的霍乱谷，恒河三角洲的混合物种生物膜。伊斯兰教和学校最近完成了一项为期一年的试点研究（作为父母补助金的补充），该研究表明：（1）V。霍乱属于混合物种生物膜，这些物种在孟加拉国Matlab附近的恒河塑料表面上形成的混合物种生物膜； （2），生物膜的物种组成在一年中变化。这些观察结果以及几丁质作为营养表面的重要性和丰度导致了以下假设：含霍乱的混合物种生物膜的种群结构随表面底层（与非营养性表面）和季节（季前，季风，季风或季度或季前外或季型）相比而变化。为了检验这一假设，这里提出的工作将使用与基于培养的16S rRNA序列的方法来确定在蒙蒙区前蒙索恩（Monsoon），季风后期和月球后期的MATLAB采样位点浸入Matlab采样位点上的几丁质或聚碳酸酯表面生物膜结构的种群结构。然后，确定的物种特异性序列将用于设计标记为荧光原位杂交（FISH）测定的标记的pligon核苷酸探针。这些探针将在项目的最后两年中使用，以确定来自几丁质和聚碳酸酯表面的每月生物膜样品的种群结构。这些结果将与水化学和霍乱病例率的变化相关。这些关键分子生态学方法的每个组成部分向ICDDR的转移，由ICDDR，B和Stanford的孟加拉国科学家进行的培训计划所完成，这将显着提高该重要中心的研究能力。