Larval mosquito feeding and microbial interactions

蚊子幼虫的摄食和微生物相互作用

• 批准号: 7526788
• 负责人: Edward D Walker
• 金额: $ 36.74万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-12-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7526788
• 关键词: Adult; Affect; Arbovirus Infections; Bacillus (bacterium); Biological; Biological Metamorphosis; Biomass; Blood; Body Size; Cellulases; Characteristics; Chitinase; Condition; Crying; Culex pipiens; Culicidae; Data; Development; Ecosystem; Environment; Enzymes; Female; Filariasis; Flavobacteria; Flavobacterium genus; Food; Genes; Genetic; Germ-Free; Goals; Growth; Growth and Development function; Habitats; Human; Individual; Longevity; Malaria; Measures; Metabolic; Modeling; Molecular; Molecular Genetics; Numbers; Nutrient; Nutritional; Ochlerotatus; Outcome; Particulate; Plants; Population; Production; Property; Proteins; Public Health; Rate; Relative (related person); Research; Resources; Role; Simulate; Source; Staging; Structure; System; Testing; Time; Toxin; Trees; Variant; base; cellulase; comparative; feeding; fitness; life history; member; microbial; microbial community; microorganism; microorganism interaction; pathogen; research study; response; survivorship; tool; trait; transmission process; vector

DESCRIPTION (provided by applicant): The growth and production of adult mosquitoes from the aquatic larval habitats is constrained by conversion of refractile organic material into ingestible and digestible microbial biomass. Rates of conversion of organic matter into microbial biomass are tempered by the quality of particulate substrates that is manifested in dual roles of inhibition and stimulation of microbial and larval growth. Our long-term goal is to delineate the biological basis for and constraints on mosquito production, to identify the efficiency of utilization of these resources, and to elaborate a realistic model of larval growth. We have identified the tree hole ecosystem for study, harboring the species Ochlerotatus triseriatus, Ochlerotatus japonicus, and Culex pipiens, two vectors of human pathogens and one an exotic invader. Research approaches include an axenic (germ-free) experimental system into which individual food sources including microorganisms can be provisioned; stable isotopic analyses (13C/12C; 15N/14N) to track larval foods to their sources; molecular analyses of microbial community structure; a functional gene array analysis of microbial genes encoding enzymes involved in large biomolecule degradation, including xylanases, cellulases, and chitinases; and microcosm and naturalistic experiments in which microbial biomass and metabolic activity relative to larval growth are quantified. A growth model is proposed in which developmental time to, and mass at, metamorphosis (i.e., pupation) are postulated to be flexible life history traits whose minima are nutritionally and genetically constrained into a pupation window defining body size and affecting adult survivorship; both are key fitness parameters and both important components of vectorial capacity. Experiments will delineate relationships among them, and reveal environmental and genetic components contributing to their variation. The current understanding of larval growth rates requires conversion efficiencies (mg food assimilated per mg food ingested) far higher than observed, thus we will iteratively test growth responses relative to natural microbial food sources of various qualities, fit observed growth data to models, and revise conversion efficiency estimates accordingly. The three mosquito species sharing the same larval habitat and resources will be compared to assess growth rates under conditions of intense intra- and interspecific competition, both to make predictions of competitive outcomes and potential for ecological displacement, and to quantify comparative efficiency of utilization of larval foods. Manipulation of the Flavobacterium component of the microbial community a dominant member with molecular genetic tools to express genes encoding proteins having larval toxin and growth inhibiting properties will be conducted, including cry toxin genes from Bacillus, and chitinases. PUBLIC HEALTH RELEVANCE Mosquitoes are responsible for transmission of large number of human pathogens, including those causing malaria, filariasis, and arboviral infections. Abundance and longevity of adult, female mosquitoes (the blood feeding and pathogen transmitting stage) are dependent upon the nutritional and other factors operating in the larval environment, the constraints of which are the focus of the research here.

描述（由申请人提供）：从水生幼虫栖息地中的成年蚊子的生长和生产受到将冷疗法有机材料转化为可观且易消化的微生物生物量的限制。有机物转化为微生物生物量的速率通过颗粒底物的质量来调节，这表现在抑制和刺激微生物和幼虫生长的双重作用中。我们的长期目标是描绘蚊子生产的生物学基础和限制，以确定这些资源利用的效率，并详细说明幼虫生长的现实模型。我们已经确定了研究的树洞生态系统，含有triseriatus ochlerotatus triseriatus，ochlerotatus japonicus和Culex pipiens，两个人类病原体的两个载体和一个外来的入侵者。研究方法包括一种轴承（无菌）实验系统，可以在其中提供包括微生物在内的各个食物来源；稳定的同位素分析（13c/12c； 15n/14n）跟踪幼虫食品的来源；微生物群落结构的分子分析；对大型生物分子降解的酶的微生物基因的功能基因阵列分析，包括木聚糖酶，纤维酶和几丁质酶；微生物和自然主义实验，其中微生物生物量和代谢活性相对于幼虫生长进行了量化。提出了一个生长模型，其中的发育时间和质量是变形（即，化合物）是柔性的生活历史特征，其最小值在营养和遗传上被限制为定义身体大小并影响成人生存的化合物窗口；两者都是关键适应性参数，也是矢量能力的重要组成部分。实验将描绘它们之间的关系，并揭示有助于其变异的环境和遗传成分。当前对幼虫生长速率的理解需要转化效率（每毫克食品摄入的食物）的转化效率远高，因此相对于自然品质的自然微生物食品来源，我们将迭代测试生长反应，拟合了观察到的生长数据对模型的拟合，并对转化效率进行了相应的修订效率估计。将比较具有相同幼虫栖息地和资源的三种蚊子物种，以评估强烈的内部和种间竞争条件下的增长率，既可以预测竞争成果和生态流离失所的潜力，又可以量化幼虫食品利用的比较效率。对微生物群落的黄杆菌成分操纵具有分子遗传工具的主要成员，以表达编码具有幼虫毒素和生长抑制特性的蛋白质的基因，包括来自芽孢杆菌的哭泣毒素基因和几丁质酶。公共卫生相关性蚊子负责传播大量人类病原体，包括引起疟疾，丝虫病和弧病毒感染的病原体。成人，雌性蚊子（血液喂养和病原体传播阶段）的丰度和寿命取决于在幼虫环境中运行的营养和其他因素，其限制是这里研究的重点。