Juvenile hormone activity in Dysdercus cingulatus Fabr by juvenile hormone esterase inhibitor, OTFP.

Application of juvenile hormone esterase inhibitor 3-octylthio-1,1,1- trifluropropan-2-one (OTFP) to 5th instar nymphs and virgin females of D. cingulatus revealed the profound role played by juvenile hormone esterase (JHE) in metamorphosis and reproduction. The ability of OTFP to cause delay and the formation of malformed nymphs, suggests that inhibition of JHE in vivo maintains a higher than normal hemolymph JH titer. It is obvious that OTFP does inhibit in vivo JHE activity in late instar nymphs. Further, the application of JHE inhibitor, OTFP to virgin females demonstrates that substituted trifluropropanones can indirectly stimulate egg development by inhibiting JHE activity in virgin females.

Modulatory influence of juvenile hormone analogue (JHa) and 20-hydroxyecdysone on lipophorin synthesis in red cotton bug, Dysdercus cingulatus Fabr.

Topical supply of methoprene, a juvenile hormone analogue (JHa) caused notable morphological disturbance in insects. Topical supply of methoprene to newly emerged adult female D. cingulatus caused notable disturbance and induced a dramatic reduction in the total haemolymph protein pattern and lipophorin production in tissues like fat body, ovary and haemolymph. Total protein concentration in haemolymph also showed significant reduction in 1 day old insects but increased slightly as age advanced. Application of 20-hydroxyecdysone (20-HE) to 2-day-old adult female stimulated protein synthesis intensively. Lipophorin levels in fat body and ovary also simultaneously increased. Densitometric analysis revealed that methoprene inhibits while 20-HE stimulates lipophorin production in D. cingulatus.

Tissue localization and partial characterization of pheromone biosynthesis activating neuropeptide in Achaea janata.

Female sex pheromone production in certain moth species have been shown to be regulated by a cephalic endocrine peptidic factor: pheromone biosynthesis activating neuropeptide (PBAN), having 33 amino acid residues. Antisera against synthetic Heliothis zea-PBAN were developed. Using these polyclonals, immunoreactivity was mapped in the nervous system of Achaea janata. Three distinct groups of immunopositive secretory neurons were identified in the suboesophageal ganglion; and immunoreactivity was observed in the corpora cardiaca, thoracic and in the abdominal ganglia. From about 6000 brain sub-oesophageal ganglion complexes, the neuropeptide was isolated; and purified sequentially by Sep-pak and reversed phase high performance liquid chromatographic methods. Identity of purified PBAN fraction was confirmed with polyclonal antibody by immunoblotting. Molecular mass of the isolated peptide was determined by matrix-assisted laser desorption/ionization mass spectrometry, and was found to be 3900 Da, same as that of known H. zea-PBAN. Radiochemical bioassay confirmed the pheromonotropic effect of the isolated neuropeptide in this insect.

Hormonal modulation of glycogen reserves In the fat body of castor semilooper Achaea janata Linn (Lepidoptera, Noctuidea).

Histochemical details of the fat body in the fifth instar larval stage, pupa and adult moth of the castor semilooper Achaea janata were elucidated in detail using light and electron microscopy in conjunction with glycogen storage patterns using polyacrylamide gel electrophoresis. The periodic-acid Schiff staining for glycogen in fat body was maximum in the spinning stage of the larva, when compared to the feeding stage and prepupal stages, and higher in the pupa than in the larva and the adult moth. In insulin injected and juvenile hormone treated fat body, glycogen deposition was more than in glucagon injected tissues. The periodic-acid Schiff stained bands in PAGE had electrophoretic mobility similar to the corresponding protein band numbers, indicating their glycoprotein nature.

Protective action of aspirin in experimental myocardial infarction induced by isoproterenol in rats and its effect on lipid peroxidation.

The protective action of aspirin in experimental myocardial infraction induced by isoproterenol was studied in rats. Aspirin treated rats showed lower mortality rate and smaller changes in the myocardium on histopathological examination when compared to corresponding animals given isoproterenol alone. Changes were also observed in the different lipid fractions studied. The ratio of cholesterol to phospholipids decreased in the heart in aspirin treated animals when compared to control rats given isoproterenol alone. The levels of lipid peroxide also showed a decrease while the activity of superoxide dismutase (SOD) and catalase registered an increase in the aspirin treated animals given isoproterenol when compared to corresponding animals given isoproterenol alone.

Effect of vitamin E on the severity of myocardial infarction induced by isoproterenol.

The effect of vitamin E administration on the severity of myocardial infarction induced by isoproterenol on rats was studied. Judging from serum enzyme activity (CPK 714 micromoles; GOT 291.7 micromoles; and GPT 155.5 micromoles), mortality rate (60 to 65% survived) and histopathological observation, vitamin E has been observed to offer very little protection to the myocardium during experimental myocardial infarction when compared to control animals given isoproterenol alone (CPK 775.8 micromoles; GOT 336.2 micromoles; and GPT 168 micromoles), mortality rate (60 to 65% survived) and histopathological observation (more or less similar). The level of lipid peroxides namely hydroperoxides (control 3.15; vitamin E + iso. 14.8); conjugated diene (4.45 and 6.85) and malondialdehyde (1.22 and 2.55) in the heart were higher in the vitamin E treated animals given isoproterenol when compared to control animals given vitamin E alone. The level of cholesterol and phospholipid was more or less similar in the control animals given vitamin E alone (183.6 and 3.12) and vitamin E treated animals given isoproterenol (170.25 and 2.49), but the ratio of cholesterol to phospholipid was higher in the vitamin E treated animals given isoproterenol when compared to control animals given vitamin E alone.