MICROFILARIAL CHITINASE AND TRANSMISSION OF FILARIASIS

微丝虫几丁质酶与丝虫病的传播

• 批准号: 2003868
• 负责人: JULIET A FUHRMAN
• 金额: $ 15.64万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-12-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2003868
• 关键词: Culicidae; Filarioidae; SDS polyacrylamide gel electrophoresis; chemical binding; chitin; disease vectors; enzyme activity; enzyme inhibitors; epitope mapping; filariasis; gerbil /jird; glycosylation; host organism interaction; isozymes; life cycle; molecular cloning; polymerase chain reaction; posttranslational modifications; protein sequence; protein structure function; proteolysis; virulence

Brugia malayi is a parasitic nematode that causes lymphatic filariasis in man. Transmission of the parasite depends upon a complex sequence of migration and development of the parasitic larvae within the mosquito vector. The role of microfilarial chitinase in transmission of brugian filariasis will be studied. Microfilarial chitinase was identified by a transmission-blocking monoclonal antibody, MF1. The appearance of the chitinase during microfilarial development coincides with the onset of the larva's ability to infect the mosquito vector. Chitinase enzyme activity in native and recombinant molecules will be examined, and known inhibitors of chitinase (allosamidin and related compounds) will be tested for their effects in vitro. It is hypothesized that the microfilarial chitinase is composed of two separate domains: one with enzymatic activity, and one that functions to localize the secreted enzyme by binding to the cuticular surface of the larva. This will be tested by proteolytic dissociation of the native molecule, and by mutagenesis of the cloned recombinant. Three possible roles for the chitinase during larval infection of the mosquito are postulated: 1) chitinase degrades a worm-derived structure that would otherwise inhibit development and moulting; 2) the enzyme degrades a mosquito-derived structure that blocks larval migration; or 3) the enzyme releases ligands that block defensive agglutinins elaborated by the mosquito. To distinguish among these alternatives, infective microfilariae will be fed to susceptible mosquitoes in the presence of inhibitors of chitinase, and phenotypically chitinase- negative microfilariae will be fed in the presence of oligosaccharides or recombinant enzyme. the progress of infection will be monitored in each case to ascertain the time and site of action of chitinase during the natural infection process. The two isozymes that comprise the MF1 antigen, p70 and p75, will be compared at the level of protein structure and function. Differences in primary sequence and post-translational modifications will be analyzed. The existence of two separate genes, or differentially processed messages, will be investigated. These studies will elucidate the role of this enzyme in parasite-vector interactions, and may thereby clarify the molecular mechanisms that operate during transmission. Furthermore, understanding the enzyme's structure and activity may point to novel control strategies for nematode parasites and the diseases they cause.

马来丝虫是一种引起淋巴丝虫病的寄生线虫 在人身上。 寄生虫的传播取决于一系列复杂的序列 蚊子体内寄生幼虫的迁移和发育 向量。 微丝虫几丁质酶在布鲁氏菌传播中的作用 将研究丝虫病。 通过传输阻断鉴定微丝蚴几丁质酶 单克隆抗体，MF1。 几丁质酶的出现 微丝蚴的发育与幼虫能力的开始同时发生 感染蚊子媒介。 天然和中性几丁质酶活性 将检查重组分子，以及已知的几丁质酶抑制剂 （阿洛糖脒和相关化合物）将在以下环境中测试其效果： 体外。 据推测，微丝蚴几丁质酶的组成 两个独立的结构域：一个具有酶活性，另一个具有酶活性 通过与角质层结合来定位分泌的酶 幼虫的表面。 这将通过蛋白水解离来测试 天然分子，以及通过克隆重组体的诱变。 几丁质酶在幼虫感染过程中的三种可能作用 蚊子被假设：1）几丁质酶降解蠕虫衍生的结构 否则会抑制发育和换羽； 2）酶 降解阻止幼虫迁移的蚊子衍生结构；或者 3）酶释放阻断防御性凝集素的配体 由蚊子详细阐述。 为了区分这些替代方案， 感染性微丝蚴将被喂给易感蚊子 几丁质酶抑制剂的存在，以及几丁质酶的表型- 阴性微丝蚴将在寡糖存在的情况下被喂养 或重组酶。 感染的进展将受到监测 每个病例都要确定几丁质酶作用的时间和部位 自然感染过程。 构成 MF1 抗原的两种同工酶 p70 和 p75 将是 在蛋白质结构和功能水平上进行比较。 差异在于 将分析初级序列和翻译后修饰。 存在两个独立的基因，或经过差异处理 消息，将进行调查。 这些研究将阐明其作用 这种酶在寄生虫-载体相互作用中的作用，从而可以阐明 传播过程中起作用的分子机制。 此外， 了解酶的结构和活性可能会带来新的发现 线虫寄生虫及其引起的疾病的控制策略。