VENOM PROTEINS OF THE ENDOPARASITIC WASP CHELONUS NEAR CURVIMACULATUS - CHARACTERIZATION OF THE MAJOR COMPONENTS

The venom apparatus of Chelonus near curvimaculatus (Braconidae) has a simple (type 2) morphology. Most of the venom is accumulated in a thin‐walled venom reservoir at the distal end of the gland filament as a 10–17% protein solution. The best results for isolation of the proteins were obtained using 7.5% sucrose in phosphate buffer, pH 7.4. There are four major proteins, with respective Mr values of 32,500, 47,000, 53,000, and 131,000. Of these, those of Mr 32,500, 53,000, and 131,000 contain carbohydrate. Most of the venom proteins are acidic with pI values between 4.9 and 6.9. The venom does not show proteolytic activity corresponding to serine or thiol proteinases, nor does it show antitrypsin or antichymotrypsin activity. Using immunoblotting techniques, it was established that during parasitization of a single host egg (Trichoplusia ni) about 1/200 of a venom reservoir equivalent is injected. All major venom proteins have been found in stung T. ni eggs; thus, no detectable changes in their molecular weight occur during injection or shortly after injection into the host. Copyright © 1990 Wiley‐Liss, Inc.