Fig. 2. Localization of CA mRNA in a whole-mount preparation of early fourth instar Ae. aegypti midgut. (A) The whole-mount gut preparation localizes CA message to specific cells of the gastric caeca (GC) and posterior midgut (PMG). The anterior midgut (AMG) epithelial cells and the malpighian tubules (MT) showed little or no labeling. (B) A subset of cardia (arrows) and GC cells display the CA message. The distal lobes of the GC, called Cap cells, display no staining (asterisks). (C) There is a distinctive labeling pattern of CA message within a specific band of PMG epithelial cells. In addition, numerous trachea are heavily labeled along the length of the midgut (arrows). Scale bars, 300 µm (A), 150 µm (B), 75 µm (C).