ADAPTATION OF LEISHMANIA TO NATURAL DIETS OF THE VECTOR

利什曼原虫对媒介自然饮食的适应

• 批准号: 3147104
• 负责人: YOSEF SCHLEIN
• 金额: $ 10.02万
• 依托单位: HEBREW UNIVERSITY OF JERUSALEM
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-04-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3147104
• 关键词: Leishmania major; arthropod borne communicable disease; communicable disease control; communicable disease transmission; diet; dietary carbohydrates; disease vectors; endopeptidases; environmental adaptation; field study; host organism interaction; leishmaniasis; nutrition related tag; pathologic process; plants; proteolysis; radiotracer; trypsin

Leishmania resides in the alimentary tract of vector sandflies, in a medium comprising the food of the fly mixed with digestive enzymes. We shall determine whether variations in the composition of the food influence the course of development of the pathogen and whether such factor may affect the natural force of transmission. One series of experiments will correlate the presence of various naturally occurring food plants and honeydew, found in the Jordan Valley, with the course of L. major infection in P. papatasi. First, these foods will be provided to laboratory-reared infected flies and the effect of each diet characterized by estimating parasite density, mortality and morphological abberations, in stained preparations of gut-contents. The criteria deduced from these experiments will be used to screen putative field diets for their effect on natural infections in vector flies. Then, we shall evaluate how frequently each of these foods are ingested in nature, by examining the guts of wild-caught flies. The prevalence of Leishmania will be correlated with the presence of particular food sources. A companion series of experiments will investigate whether blood of different animals, endemic to the Jordan Valley, affects the course of infection in sandflies. Thus, we shall determine whether leishmanial infection is diminished or eliminated after infected flies feed on particular naturally occurring animals. Because midgut proteolysis in vector sandflies varies between different kinds of hosts and the major glycoconjugates of the Leishmania influences these digestive enzymes, we shall compare the trypsin-like enzymes secreted in sandflies after feeding on this array of hosts. The proposed analysis of the diet of the vector as a factor that affects vector competence and the force of leishmanial transmission constitutes a novel approach to the epidemiology of the leishmaniases. We anticipate that these results will contribute to a basic understanding of vector- pathogen interactions and may provide methods useful in the control of these infections.

利什曼原虫存在于媒介白蛉的消化道中，在介质中 由苍蝇的食物与消化酶混合而成。 我们将 确定食物成分的变化是否会影响 病原体的发展过程以及该因素是否会影响 自然的传播力。 一系列实验将把各种自然现象的存在联系起来 在约旦河谷发现的食用植物和蜜露， P. papatasi 中 L. Major 感染的过程。 首先，这些食物 提供给实验室饲养的感染苍蝇以及每种饮食的效果 其特点是估计寄生虫密度、死亡率和形态 肠道内容物染色制剂中的畸变。 推导出来的标准 这些实验中的结果将用于筛选假定的野外饮食 它们对媒介苍蝇自然感染的影响。 那么，我们将 评估每种食物在自然界中被摄入的频率，通过 检查野生苍蝇的内脏。 利什曼原虫的流行将 与特定食物来源的存在相关。 一系列伴随实验将调查血液是否 约旦河谷特有的不同动物影响着 白蛉感染。 因此，我们将确定利什曼原虫是否 受感染的苍蝇进食后，感染就会减少或消除 特定的自然存在的动物。 因为中肠蛋白水解作用 媒介白蛉在不同种类的宿主和主要宿主之间有所不同 利什曼原虫的糖复合物影响这些消化酶，我们 应比较喂食后白蛉中分泌的类胰蛋白酶 在此主机阵列上。 建议对媒介饮食作为影响因素进行分析 媒介能力和利什曼原虫传播力构成了 利什曼病流行病学的新方法。 我们预计 这些结果将有助于对向量的基本理解 病原体相互作用，并可能提供可用于控制病原体的方法 这些感染。