Digestive processes of hematophagous insects X. Effects of mammalian sera upon two trypsins from female horse flies and deer flies (Diptera: Tabanidae)

In this further part of a series [see RAE/B 65, 1086, etc., 2168], the effects are described of sera from cow, dog, horse, man, pig, rabbit and sheep on trypsins partially purified from tabanids by means of Sephadex gel filtration and DEAE-cellulose chromatography at a pH of 7. Trypsins from all the 3 species of Chrysops and the 6 species of Hybomitra tested that were eluted from DEAE-cellulose with 0.1 or 0.2 M potassium chloride were inhibited by mammalian sera. Trypsins from 2 species of Chrysops and 4 of Hybomitra eluted from DEAE-cellulose with 0.3 or 0.4 M potassium chloride were activated by mammalian sera. The effects of cow serum upon trypsin from C. frigidus O.-S., H. lasiophthalma (Macq.) and H. nuda (McDunn.) were found to depend on the degree of purification of the trypsin. A trypsin activator was found in the mid-gut of C. frigidus and H. nuda.