Activities of Bacillus thuringiensis insecticidal crystal proteins Cyt1Aa and Cyt2Aa against three species of sheep blowfly.

The toxicity of Bacillus thuringiensis Cyt1Aa protein to sheep blowfly larvae depends on its solubilization and proteolytic activation. Cyt1Aa crystals were not toxic. Full-length and trypsin-digested Cyt1Aa proteins were toxic to larvae of three species of sheep blowfly. Neither full-length nor trypsin-digested Cyt2A soluble crystal proteins were toxic.

Surface morphology of gregarine spores found in the haemocoel of some New Zealand hepialids (Lepidoptera, Insecta).

The spores of three gregarine species which produce cysts in the haemocoel of New Zealand hepialids are described and their host species are listed. One of the species, Diplocystis oxycani Dumbleton, has been previously described, but the other two are undescribed. Since the undescribed species form haemocoelic cysts in insects and because their vegetative stages are unknown, they have temporarily been designated Pseudomonocystis, and named P. spinosus n. sp. and P. hexaporcatus n. sp. The spores of each species were examined with the SEM and each was found to be biconical with a polar cap. However, they could be distinguished by their very distinctive surface ornamentation. Spores of D. oxycani were covered with short ridges arranged in a helical pattern, those of P. spinosus n. sp. were covered with spines, and those of P. hexaporcatus had six longitudinal ridges. The ultrathin sections showed that the spore wall of D. oxycani comprised up to six layers. D. oxycani was recorded from Wiseana umbraculata, W. jocosa, W. copularis, and Aoraia aurimaculata. P. spinosus was recorded from W. umbraculata and A. aurimaculata, and P. hexaporcatus was recorded from an unidentified hepialid collected from the Great Moss Swamp, Otago, New Zealand.

Factors affecting the use of immunoosmophoresis for the detection of two insect riboviruses.

Some of the factors affecting the formation of precipitin lines during immunoosmophoresis were investigated using two unrelated insect riboviruses, Flock House virus (FHV) and cricket paralysis virus (CrPV). Precipitin lines formed in under 90 min. Concentrations of 200-400 ng/ml of FHV were routinely detected but occasionally the end-point was as low as 50 ng/ml. With CrPV, 1500 ng/ml was the routine detectable level. The sensitivity of the assay was largely unaffected by the presence of insect homogenate. Maximum detection of virus was obtained when the antigens and antibodies were at optimal proportion and excess of either reagent resulted in the blurring of precipitin lines. Immunoosmophoresis proved to be a rapid and inexpensive method of detecting negatively charged viruses in crude insect extracts and can, in some cases, have a sensitivity approaching that of more sophisticated serological techniques.