Search

The tritium-labeled bis-norleucine analog of Helicoverpa zea pheromone biosynthesis-activating neuropeptide ([3H]NLPBAN) was incubated in vitro with hemolymph from Manduca sexta or H. zea adult females. The incubations resulted in the formation of several tritium-labeled degradation products. At a [3H]NLPBAN concentration of 0.9 microM the degradation proceeded at a very slow but physiologically plausible rate (2-10 fmol/min/microliters hemolymph). The primary [3H]NLPBAN degradation reaction in M. sexta hemolymph was not inhibited by 20 microM leupeptin, 0.1 mM amastatin, 1 mM EDTA, 1 mM EGTA, 1 mM 1,10-phenanthroline, or 2 mM 4-(2-aminoethyl)benzenesulfonyl fluoride; but secondary reactions may have been affected, as some of the inhibitors changed the radio-HPLC profile of the degradation products. It is concluded that hemolymph of M. sexta and H. zea contains peptidase(s) capable of inactivating circulating PBAN.

Catalase (CAT), glutathione S-transferase (GST) and superoxide dismutase (SOD) activi- ties were determined in postmitochondrial fractions of tissue homogenates (spermathecae, muscle and ventriculi), in hemolymph plasma, and in semen of honey bees. The highest CAT activity was found in semen (4.8 mU/μg fresh weight), and the enzyme was confined to the spermatozoa. CAT and GST activities of ventriculi exceeded those of other tissues and hemolymph, CAT being highest in mated queen ventriculi (2.7 mU/μg) and GST highest in worker ventriculi (10 mU/mg). Spermathecae of mated queens had higher CAT and GST activities (0.84 mU/μg, and 2.4 mU/mg, re- spectively) than virgin spermathecae (0.15 mU/μg, and 1.6 mU/mg). SOD activities (15-59 mU/μg) varied less than activities of CAT or GST between tissues. Seminal plasma contained two thirds of the total SOD activity of semen and one third was in the spermatozoa. The substantial activities of all three enzymes in spermathecae of mated queens suggest their involvement in the long-term protec- tion of the spermatozoa from oxidative stress. Apis mellifera / catalase / glutathione S-transferase / superoxide dismutase