Insect growth inhibition,antifeedant and antifungal activity of compounds isolated/derived from Zingiber officinale Roscoe (ginger) rhizomes

Fresh rhizomes of Zingiber officinale (ginger), when subjected to steam distillation, yielded ginger oil in which curcumene was found to be the major constituent. The thermally labile zingiberene‐rich fraction was obtained from its diethyl ether extract. Column chromatography of ginger oleoresin furnished a fraction from which [6]‐gingerol was obtained by preparative TLC. Naturally occurring [6]‐dehydroshogaol was synthesised following condensation of dehydrozingerone with hexanal, whereas zingerone and 3‐hydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)butane were obtained by hydrogenation of dehydrozingerone with 10% Pd/C. The structures of the compounds were established by ¹H NMR, ¹³C NMR and mass (EI‐MS and ES‐MS) spectral analysis. The test compounds exhibited moderate insect growth regulatory (IGR) and antifeedant activity against Spilosoma obliqua, and significant antifungal activity against Rhizoctonia solani. Among the various compounds, [6]‐dehydroshogaol exhibited maximum IGR activity (EC₅₀ 3.55 mg ml ^?1) while dehydrozingerone imparted maximum antifungal activity (EC₅₀ 86.49 mg litre^?1). © 2001 Society of Chemical Industry     

Growth-inhibiting activity of azadirachtin onCorcyra cephalonica

The growth-inhibiting properties of azadirachtin, a bioeffective triterpenoid compound isolated from neem (Azadirachia indica A. Juss) seeds, was evaluated on the rice moth,Corcyra cephalonica Staint., a serious pest of stored products. By topical application of various azadirachtin doses (0.5 to 10 μg/larva) in methanol to last-instar spinning stage larvae, development was inhibited. The effect was dose-dependent; at higher doses, many of the insects remained in the larval stage (55% with 10 μg/larva). Disturbance of both larval-pupal and pupal-adult molting is discussed and interpreted as interference with the morphogenetic hormone pool size.     

Genetics of soybean-Heterodera glycines system

Genetics of resistance to soybean cyst nematode (SCN), Heterodera glycines Ichinohe is very complex. Crosses involving PI 437654, which is resistant to all races of cyst nematodes with other sources of resistance (Peking, PI 88788, and PI 90763) indicated that resistance to race 3 was controlled by four genes, two of which were dominant resistance genes and the other two were recessive resistance genes. For race 5, a four gene model with two recessive and two dominant resistance genes in epistasis has been proposed. For race 14, the results suggested a three gene model with one dominant and two recessive alleles. Several other plant introductions have been isolated which have different genes conditioning resistance. Most of the currently grown soybean varieties derived resistance from Peking and/or PI 88788. Resistance to SCN in these soybean varieties has broken down because of the emergence of several new races and populations of SCN. The use of PI 437654 or Hartwig and other plant introductions with different genes for resistance will broaden genetic diversity and stabilize yield.     

The effects of bovine respiratory syncytial on normal ovine lymphocyte responses to mitogens or antigens in vitro

In the present study peripheral blod mononuclear cells (MNC) obtained from normal uninfected lambs were used to study the possible effects of bovine respiratory syncytial virus (BRSV) on lymphocyte responses to the mitogens, phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) in vitro. Live BRSV had a depressive effect on the proliferative responses of normal MNC to PHA, Con A and PWM. Inactivated BRSV and a commercial preparation of prostaglandin E2 were also found to depress the proliferative responses of normal ovine MNC to PHA but recombinant tumour necrosis factor-alpha (TNF-alpha) had no such effect. Serum samples obtained from BRSV-infected lambs contained substances inhibitory to PHA-driven lymphocyte blastogenesis. Memory blastogenic responses to border disease virus (BDV) of lymyphocytes obtained from lambs previously primed with BDV were significantly reduced when lymphocytes were exposed to infectious BRSV.     

Comparative pathogenesis of serotype 1 and variant serotype 1 isolates of infectious bursal disease virus and their effect on humoral and cellular immune competence of specific-pathogen-free chickens

Specific-pathogen-free chickens inoculated with isolate VA (variant A) or isolate IM of infectious bursal disease virus (IBDV) were examined for mitogenic response to T-cell mitogens, primary and secondary antibody response to sheep erythrocytes and Brucella abortus, and gross and histologic lesions in thymus and bursa. Both isolates induced comparable depression in the mitogenic and antibody response, and both caused extensive gross and histologic lesions in the bursa of Fabricius. However, bursal necrosis induced by the IM isolate was accompanied by an inflammatory response, whereas the inflammatory component was lacking in the lesion induced by the VA isolate. Furthermore, the IM isolate induced extensive lesions in the thymus, but the VA isolate did not.     

Evaluation of Cytotoxic Responses Caused by Selected Organophosphorus Esters in Chick Sympathetic Ganglia Cultures

Ten day old chick sympathetic ganglia cultured in a microslide assembly were treated with a selected group of organophosphate pesticides to evaluate their cytotoxicity ranges, and the usefulness of such a model for screening pesticides. Examination by phase contrast and light microscopy for chemically-induced morphological alteration of nerve fibers, glial cells and neurons provided the criteria for quantitation and assessment of the toxic effects. Concentrations that produced half-maximal effects ranged from 1 × 10^-6M (severely toxic) for methylparathian, diazinon, paraoxon, mevinphos, diisopropylfluorophosphate, tri-o-tolyl phosphate and its mixed isomers to a 1 × 10^-3M (intermediate) for malathion, leptophos, coumaphos, mono- and dicrotophos. Some or no effects were evident at 1 × 10^2-M for O'ethyl-O-p-nitrophenyl phenyl phosphonothioate, tri-m-tolylphosphate, chlorpyriphos and triphenyl phosphate. In all instances, nerve fibers were more sensitive than neurons or glial cells to insecticides. All cellular growth was inhibited at 1 × 10^-2M (except triphenyl phosphate). Below 1 x 10^-7M, no inhibitory effects were evident. The secondary abnormalities included decreased cellular migration, diffuse cellular growth pattern, increased vacuolization, nerve fiber swelling and cellular degeneration. The cytotoxic effects of these chemicals do not appear to be related to in vivo toxicity or cholinesterase inhibition potential.     

Detection of rinderpest antibodies

Rinderpest antibodies were detected by employing the fluorescent antibody test (FAT) and the immunoperoxidase test (IPT) and the results were compared with the counterimmuno electrophoresis test (CIE). FAT was found to be the most sensitive in detecting post-vaccinal antibodies followed by IPT and CIE tests.