ACID-PHOSPHATASE-ACTIVITY IN HEMOLYMPH OF THE MIGRATORY GRASSHOPPER, MELANOPLUS-SANGUINIPES, DURING BEAUVERIA-BASSIANA INFECTION

The distribution and abundance of acid phosphatase (AP) in hemolymph ( HL), plasma (PM) and hemocyte lysate supernatant (HLS) of the migrator y grasshopper, Melanoplus sanguinipes infected with Beauveria bassiana (strain GK 2016) has been examined. AP activity was determined at int ervals from 30 min to 60 h postinjection of 2 mul of 1 x 10(8) conidia /ml per grasshopper. The enzyme was detected with the substrate beta-g lycerophosphate in sodium acetate acetic acid buffer form hemocytes (H C) and with p-nitrophenol phosphate sodium salt for HL, PM and HLS. In results of experiment 1 proportion of HC showing AP activity increase d 1-2 h, then returned to normal after 4 h. However, in B. bassiana-in jected grasshoppers, a second increase was noted 24 h later which was not seen in the Tween-80-injected insects. Uninjected controls showed no change with time in the proportion of HC with AP activity. Studies were also made of the distribution of AP activity in the HL, PM, and H LS. AP activity in HL appeared to vary with the sex of the grasshopper s. Females showed increase in AP activity in HL 18-24 h after injectio n with B. bassiana, whereas males only showed an increase 1 h after in jection. Assay of HLS showed that the level of AP activity did not cha nge significantly throughout the experiment. Changes in AP activity in PM, in both B. bassiana - and Tween-80-injected insects (both sexes) paralleled those of the HL, indicating that the enzyme is released fro m the HC. The observations are discussed in terms of the possible role of AP in the immune response of M. sanguinipes.