Isolation and characterization of the 32.5 kDa protein from the venom of an endoparasitic wasp.

The major venom proteins from the endoparasitic wasp were analyzed for distribution in the venom gland. A 32.5 kDa protein was purified from the venom gland of the Chelonus near curvimaculatus wasp. The protein accounts for about 25% of the total protein content of the venom and each gland contains 3-6 pmol of this component. The protein is acidic in nature and anion-exchange chromatography facilitated the purification of the protein to apparent homogeneity. On testing the purified protein by in vivo bioassay, it was found to elicit an effect comparable with the complete venom. The protein does not appear to have any disulfide bonds of major structural importance exposed under SDS-denaturing conditions. Products of chemical partial digest of the purified protein at the methionyl residues by cyanogen bromide were analyzed by SDS-PAGE. The 27.6 kDa fragment retained an epitope to an antibody raised against total Chelonus venom proteins, whereas no epitopes were detected for 4.9 and 0.6 kDa fragments.

Kinins in ant venoms--a comparison with venoms of related Hymenoptera.

1. Venom preparations have been made of six ant, one pompilid wasp, two mutillid wasp, and four social wasp species. 2. The venoms were analysed pharmacologically in order to detect kinin-like activity. 3. Due to the small amounts of venoms available only a cascade of smooth muscle preparation could be used. 4. Kinin activities have been found in five ant venoms and in four social wasp venoms. 5. No kinin activity has been found in the venoms of the pompilid and mutillid wasps. 6. All ant venoms also contain unidentified agonists for vertebrate smooth muscle preparations.

Identification of the octapeptide lophyrotomin in the European birch sawfly (Arge pullata).

Larvae of the European birch sawfly Arge pullata were shown to contain lophyrotomin, an octapeptide liver toxin containing four D-amino acids. Lophyrotomin was previously isolated from Lophyrotoma interrupta sawfly larvae in Australia.

Two kinins isolated from an extract of the venom reservoirs of the solitary wasp Megascolia flavifrons.

From an extract of the venom reservoirs of the wasp Megascolia flavifrons two kinins have been isolated. The sequences of amino acids are: Arg-Pro-Pro-Gly-Phe-Thr-Pro-Phe-Arg (Thr6-bradykinin) and Arg-Pro-Pro-Gly-Phe-Thr-Pro-Phe-Arg-Lys-Ala (Thr6-bradykinin-Lys-Ala). The bradykinin-like effects of the venom on a number of vertebrate smooth muscle preparations can be explained by the actions of these kinins.

Retinoid composition in the compound eyes of insects.

Retinoids in the compound eyes of insects in ten orders were extracted by the oxime method and analysed by HPLC. Four geometrical isomers (13-cis, 11-cis, 9-cis and all-trans) of syn and anti retinal oximes, and syn and anti 3-hydroxyretinal oximes were separated in a single analysis by a stepwise eluent condition. The amounts of the two isomers, syn 11-cis and syn all-trans, were quantified. 11-Cis 3-hydroxyretinal was detected in six orders: Lepidoptera, Diptera, Coleoptera, Neuroptera, Hemiptera and Odonata, and retinal and 3-hydroxyretinal were found together in the compound eyes of some species of Coleoptera and Odonata. We conclude that early in their phylogeny, insects had the ability to use 3-hydroxyretinal as the chromophore of visual pigment. Peaks corresponding to syn 9-cis and 13-cis 3-hydroxyretinal oximes were observed on the chromatogram of extracts from fly heads and compound eyes of cicadas. Retinol and 3-hydroxyretinol were also analysed and quantified relative to retinal and 3-hydroxyretinal. Larger amounts of the alcohols than the aldehydes were found in the compound eyes of butterflies, hornets, cicadas and grasshoppers, which are diurnal insects. 3-Dehydroretinal has not been detected in insects.

Purification and properties of a presynaptically acting neurotoxin, mandaratoxin, from hornet (Vespa mandarinia).

A hornet (Vespa mandarinia) neurotoxin, mandaratoxin (MDTX), was purified by simple procedures with column chromatography made on Sephadex G-50 and CM-Sephadex by using an acetate buffer. The molecular weight of homogeneous MDTX was calculated to be approximately 20000 by gel filtration, NaDodSO4 disc gel electrophoresis, and amino acid analysis. MDTX is a single-chain polypeptide. MDTX did not migrate electrophoretically in a basic buffer at pH 8.3 but did so when the buffer was acidic, at pH 4.3. The isoelectric point of the toxin was determined at 9.1 by isoelectric focusing. A relatively high amount of lysine was found in the amino acid analysis. A280nm1% was 15.1. Glucosamine and galactosamine were not detectable by amino acid analysis. MDTX had neither hemolytic nor enzymatic activity. The toxin was heat labile. By use of neuromuscular junctions of a lobster walking leg, it was found that the nanomole range of MDTX irreversibly blocked the excitatory postsynaptic potential without appreciable change in the resting conductance of the postsynaptic membrane. Intracellular recording from the presynaptic nerve fiber showed that MDTX blocked the action potential mainly by reducing the sodium current.

An insect glycoprotein: a study of the particles responsible for the resistance of a parasitoid's egg to the defence reactions of its insect host.

A study has been carried out of the chemical composition and physical structure of small particles, 130 nm in diameter, isolated from the calyx of the ichneumon, Nemeritis canescens. The particles are vesicular, consisting of a densely-staining core surrounded by an outer membrane. The core of the particles is made up of protein and carbohydrate in the ratio 100:17; no nucleic acid was detected. The basic chemical subunit of the core of the particles appears to be a glycoprotein of molecular mass ca. 45 000. The basic structural subunit of the core, however, is a short, hollow cylinder, about 10 nm across. It seems likely that several chemical subunits make up one structural subunit, and that many structural subunits, surrounded by the membrane, make up a single particle.

Vespulakinins: new carbohydrate-containing bradykinin derivatives.

Two structurally similar and highly active glycopeptides have been isolated from extracts of yellow jacket venom sacs by ion-exchange and droplet countercurrent chromatography procedures. Vespulakinin 1 (heptadecapeptide) and vespulakinin 2 (pentadecapeptide) are both highly basic and contain the nonapeptide bradykinin at their carboxy termini. Most unique is the presence of carbohydrate. Vespulakinins are the first reported naturally occurring glycopeptide derivatives of bradykinin and the first reported vasoactive glycopeptides.