Insect Biochemistry - Excretion. Kuang-Hui Lu Department of Entomology National Chung Hsing University. CONTENTS. Introduction The Malpighian tubules Ultrastructure of Malpighian tubule cells Formation of primary urine in Malpighian tubules
Department of Entomology
National Chung Hsing University
Fig. A generalized scheme of excretion showing the collection of fluid in the Malpighian tubules, and extensive reabsorption of water, K+, and useful substances from the hindgut, primarily the rectum.
By analyzing the primary urine formed in the droplets, it was discovered that it was isosmotic with the hemolymph, but with potassium concentrations up to 20 times higher.
dehygrogenaseFig. Pathway for the synthesis of uric acid from nucleic acids and protein.
e.g. blowfly larvae and some cockroaches and locusts.
Fig. The general structure of a Malpighian tubule cell from the proximal tubule segment of the last instar of Drosophila melanogaster that illustrates extensive basal infoldings, a relatively short path across the narrow cell, and long microvilli on the apical surface of the cells.
(from the stick insect Carausius morosus)