ABSTRACT
In this chapter, the insect cell line will be an interesting tool to investigate the primary mode of action of various inhibitors, including the benzoylphenylureas. Used in biochemical screening systems, it will facilitate the molecular identification of new targets for alternative arthropod-specific growth regulators. In general, solubilization attempts with different detergents deteriorate insect chitin synthase activity with only low concentrations of octyl-ß-d-thioglucopyranoside (OTG) being compatible. After OTG treatment the decrease in activity could be restored at best with phosphatidylcholine-1 and phosphatidylserine, whereas other phospholipids were inefficient, indicating a selective requirement of chitin synthase for these membrane components. The distribution of chitin synthase activity in all membrane fractions tested may indicate that chitin formation takes place at various compartments in the cell. GTP binding proteins are known to mediate exocytosis, which is assumed to play a role in secretion of chitin during cuticle synthesis.
