BRUSH-BORDER MEMBRANE AND AMINO-ACID-TRANSPORT

Fundamental differences in midgut structure, physiology, brush border proteins, and transporters among Leptinotarsa decemlineata, lepidopter an caterpillars, other insect taxa, and vertebrates are reviewed. The effects of dietary protein concentration on Manduca sexta midgut amino acid transport and brush border membrane proteins are reported. M. se xta fed diet with reduced protein had elevated levels of leucine amino peptidase in the brush border membrane. No changes in amino acid trans port or alkaline phosphatase activity due to dietary differences were detected. Changes in brush border proteins could affect the toxicity a nd pathogenicity of microbial agents. (C) 1996 Wiley-Liss, Inc.