Cellular and molecular mechanisms of ion transport and excretion in insect and crustaceans

本研究探讨了运输上皮细胞如何分泌毒素，并调节昆虫和甲壳类动物体内的水，离子，酸和碱的水平。上皮是在两个隔室之间形成屏障的细胞层，并且其运输诸如无机盐（钠、氯化物等）的物质。以及水在一个流体填充隔室（通常是外部隔室）和第二内部隔室之间。外部隔室中的流体的实例包括流过水生物种的鳃的水、消化道的内容物以及排泄系统内包含的尿液或血液滤液。“内部”隔室中的流体的实例包括血液和细胞外液，其将营养物输送到肠道和排泄系统或从肠道和排泄系统输送营养物。上皮细胞分泌或再吸收离子、营养物、废物、毒素或来自特定隔室的水的活动可以通过释放到循环系统中的激素来控制。这些激素与细胞膜上的受体结合并激活细胞内第二信使系统。这种信号级联反应通常导致转运特定离子的膜蛋白的活化。对昆虫中运输上皮细胞的机制和控制的研究提供了三个益处：1）了解昆虫害虫物种中运输上皮细胞的细胞机制和激素控制有助于合理设计新颖的和环境友好的控制措施。例如，了解上皮细胞排泄有毒物质的机制有助于开发在害虫中阻断这种排泄的化合物。2)了解运输上皮细胞的机制对于了解昆虫和甲壳类动物如何适应不同的环境以及自然或人为变化（例如环境污染）如何对这些动物产生有害影响至关重要。 3)昆虫和甲壳类动物的上皮组织为理解排泄和离子转运的细胞机制提供了有用的模型系统。使用遗传特征良好的物种，如果蝇，使我们能够检查控制特定上皮转运蛋白表达的基因突变的影响。

This research examines how transporting epithelia excrete toxins and regulate the levels of water, ions, acids and bases within insects and crustaceans. Epithelia are layers of cells which form a barrier between two compartments, and which transport materials such as inorganic salts (sodium, chloride, etc.) and water between one fluid-filled compartment, often external, and a second internal compartment. Examples of fluids in external compartments include water flowing over the gills of an aquatic species, the contents of the digestive tract, and urine or blood filtrate contained within the excretory system. Examples of fluids in 'internal' compartments include the blood and extracellular fluids which transport nutrients to or from the gut and excretory system. The activities of epithelia which secrete or reabsorb ions, nutrients, waste materials, toxins or water from particular compartments can be controlled by hormones released into the circulatory system. The hormones bind to receptors in cell membranes and activate intracellular second messenger systems. This cascade of signaling often leads to activation of membrane proteins which transport particular ions. Research into the mechanisms and control of transporting epithelia in insects provides three benefits: 1) Knowledge of the cellular mechanisms and hormonal control of transporting epithelia in pest species of insect facilitates rational design of novel and environmentally-benign control measures. For example, understanding the mechanisms of excretion of toxic materials by epithelia aids development of compounds which block such excretion in pest insects. 2) Understanding the mechanisms of transporting epithelia is central to understanding how insects and crustaceans adapt to different environments, and how natural or man-made changes (e.g. environmental pollution) may have deleterious effects on these animals. 3) Epithelial tissues of insects and crustaceans provide useful model systems for understanding the cellular mechanisms of excretion and ion transport. The use of genetically well-characterized species, such as the fruit fly, allows us to examine the effects of mutations in genes controlling the expression of specific epithelial transporters.