MORPHOFUNCTIONAL STRUCTURE OF THE HEMOCYT E POPULATION IN GALLERIA-MELLONELLA L. (LEPIDOPTERA, PYRALIDAE) DURING INFECTION

Using marker enzymes, we have identified certain cell pools in the sub population of hemocytes in hemolymph of W-th instar larvae of G. mello nella. The markers used were phenoloxidase, peroxidase, and esterase. We studied changes in the population structure of hemocytes during the infection process and in response to suboptimal temperature (22 degre es C). Esterase activity was present in virtually all hemocytes (90-97 %) irrespective type. The amount of cells with esterase activity did n ot change either upon infection with Bacillus thuringiensis ssp. galle riae or in response to the low temperature. Peroxidase activity could be found in all granulocytes and in part of plasmatocytes and prohemoc ytes. The number of peroxidase-positive hemocytes did not change durin g the infection, irrespectively of the technique used to infect the la rvae, but diminished drastically at the lower temperature (from 73 to 3%). When bacteria were injected into the larvae, the amount of phenol oxidase-positive cells increased (maximally up to 10% after one day) a nd sharply diminished three days after the injection. When the infecti on was achieved by the oral route, the decrease in the number of pheno loxidase-positive cells (down to 0.1%) could be seen one day later. Th e suboptimal temperature did not affect the amount of phenoloxidase-po sitive hemocytes. Reduction of nitroblue tetrazolium (NET) in plasmato cytes and granulocytes has been demonstrated. The amount of cells capa ble of reducing nitroblue tetrazolium increased 4 h after the injectio n of bacteria into the larval hemocel. When luminol was used, we did n ot find any significant increase in chemiluminescence.