King D G
Department of Anatomy, School of Medicine, Southern Illinois University, Carbondale 62901.
J Morphol. 1988 Jun;196(3):253-82. doi: 10.1002/jmor.1051960302.
The peritrophic membrane of Drosophila melanogaster consists of four layers, each associated with a specific region of the folded epithelial lining of the cardia. The epithelium is adapted to produce this multilaminar peritrophic membrane by bringing together several regions of foregut and midgut, each characterized by a distinctively differentiated cell type. The very thin, electron-dense inner layer of the peritrophic membrane originates adjacent to the cuticular surface of the stomadeal valve and so appears to require some contribution by the underlying foregut cells. These foregut cells are characterized by dense concentrations of glycogen, extensive arrays of smooth endoplasmic reticulum, and pleated apical plasma membranes. The second and thickest layer of the peritrophic membrane coalesces from amorphous, periodic acid-Schiff-positive material between the microvilli of midgut cells in the neck of the valve. The third layer of the peritrophic membrane is composed of fine electron-dense granules associated with the tall midgut cells of the outer cardia wall. These columnar cells are characterized by cytoplasm filled with extensive rough endoplasmic reticulum and numerous Golgi bodies and by an apical projection filled with secretory vesicles and covered by microvilli. The fourth, outer layer of the peritrophic membrane originates over the brush border of the cuboidal midgut cells, which connect the cardia with the ventriculus.
黑腹果蝇的围食膜由四层组成，每层都与贲门折叠上皮衬里的特定区域相关联。上皮组织通过将前肠和中肠的几个区域聚集在一起，适应产生这种多层围食膜，每个区域都以独特分化的细胞类型为特征。围食膜非常薄且电子致密的内层起源于口道瓣的角质表面附近，因此似乎需要下面的前肠细胞做出一些贡献。这些前肠细胞的特征是糖原浓度高、滑面内质网广泛排列以及顶端质膜呈褶皱状。围食膜的第二层也是最厚的一层，由瓣膜颈部中肠细胞微绒毛之间的无定形、过碘酸 - 希夫阳性物质融合而成。围食膜的第三层由与贲门外壁高大的中肠细胞相关的细电子致密颗粒组成。这些柱状细胞的特征是细胞质中充满广泛的粗面内质网和大量高尔基体，顶端突起充满分泌小泡并被微绒毛覆盖。围食膜的第四层也是最外层，起源于立方中肠细胞的刷状缘上方，这些细胞将贲门与心室连接起来。
