The Role of Vacuolization in Rapid Fluid Secretion by InsectMalpighian Tubules

弹簧液泡化是指细胞内膜结合的“囊”或液泡的形成。在过去的三十年里，液泡存在于各种参与细胞运输的动物组织中，包括哺乳动物的肾、肾、肝脏、乳腺和脊椎动物的附睾，以及无脊椎动物的排泄器官（触角腺和马氏小管），这些都被记录在科学文献中。尽管液泡的存在不再有争议，但液泡的功能和对流体输送的总体贡献仍然是推测性的。Drs。Spring和Felgenhauer假设这些液泡参与胞吞作用（流体和溶质在细胞间的运动），并对快速流体运输有重要贡献。通过使用生理方法和显微镜（光，共聚焦扫描和透射电子显微镜），pi的目标是在运动方向，来源，内容，体积和目的地方面表征液泡。pi还将研究细胞的结构元素（细胞骨架）对液泡运动的贡献，并假设这些液泡与围绕管腔（顶端）的膜融合，如果有的话，液泡对液体分泌的贡献是直接的，还是作为改变顶端膜的机制，或者作为渗透物的来源。蟋蟀的马氏小管提供了一个很好的模型系统来研究细胞运输，因为它们的可用性、相对容易的实验操作和与其他运输组织（包括肾小管）惊人的细胞相似性。此外，蟋蟀马尔比氏小管的快速液体分泌总是与广泛的空泡化有关。这项研究的结果将有助于进一步了解分泌过程的基本机制，其应用范围从昆虫控制到脊椎动物肾脏生理学。

9807948 Spring Vacuolization refers to the formation of membrane-bound "sacs" or vacuoles within cells. Over the past thirty years, the presence of vacuoles in a variety of animal tissues involved in cellular transport, including the mammalian kidney nephron, liver, mammary glands and epididymis of vertebrates as well as the excretory organs of invertebrates (antennal glands and Malpighian tubules), has been documented throughout scientific literature. Although their presence is no longer argued, vacuole function and overall contribution to fluid transport remains speculative. Drs. Spring and Felgenhauer hypothesize that these vacuoles are participating in transcytosis (movement of fluid and solutes across cells) and contribute significantly to rapid fluid transport. By employing both physiological methods and microscopy (light, confocal scanning and transmission electron microscopy), the PIs objective is to characterize the vacuoles in terms of direction of movement, source, content, volume, and destination. The PIs will also investigate the contribution of the structural elements of the cell (cytoskeleton) to vacuolar movement and assuming that these vacuoles fuse with membrane surrounding the lumen (apical), what contribution, if any, do vacuoles make to fluid secretion either directly, or as a mechanism to alter the apical membrane, or as a source of osmolytes. The Malpighian tubules of the house cricket provide an excellent model system to investigate cellular transport due to their availability, relative ease of experimental manipulation and striking cellular similarities to other transport tissues including kidney tubules. In addition, rapid fluid secretion in cricket Malpighian tubules is always associated with extensive vacuolization. The results of this investigation will serve to further our knowledge of basic mechanisms of secretory processes in general with applications ranging from insect control to vertebrate renal physiology.