Antifeedant activity of a novel 6-(4,7-hydroxy-heptyl) quinone? from the leaves of the milkweed Pergularia daemia on the cotton bollworm Helicoverpa armigera (Hub.) and the tobacco armyworm Spodoptera litura (Fab.)

The effects of crude extracts and an isolated compound from the leaves of milkweed, Pergularia daemia (Forssk) Choiv., on the antifeedant activity against two important lepidopteran pests, Helicoverpa armigera (Hub.) and Spodoptera litura (F.), were studied. Maximum antifeedant activity was recorded in ethyl acetate crude extract against H. armigera (70.3%) and S. litura (71.82%) at 1% concentration. Ethyl acetate crude extract was further subjected to column chromatography, which was performed using hexane as initial solvent and then by increasing the polar strength using ethyl acetate. Fractions collected at hexane and ethyl acetate (80:20) yielded 6-(4,7-hydroxy-heptyl) quinone, a novel compound which showed significant antifeedant activity against H. armigera (80.22% at 2000 ppm) and S. litura (68.31% at 2000 ppm).     

Antifungal activity of 1,3-disubstituted symmetrical and unsymmetrical thioureas

1,3-disubstituted aliphatic and aromatic symmetrical and unsymmetrical thioureas were synthesised by novel routes and the antifungal activities of these compounds against two plant pathogens, Pyricularia oryzae and Drechslera oryzae were studied in Czapek-Dox medium at four different concentrations using acetone as the control and the structure-activity relationship among the substituted thioureas is reported. © 1998 SCI.     

Genetic resources for arcelin,a stored product insect antimetabolic protein from various accessions of pulses of Leguminosae

Pulses, the most important source of high-quality dietary proteins are prone to serious damage due to insect pests, of which 20–25% damage was inflicted by stored product bruchid pest, Callosobruchus maculatus (F.). An alternative approach to control these insect pests apart from fumigation is the use of primary metabolites involved in plant defense mechanism. In the present study, one of such molecule, an insect anti-metabolic protein, arcelin was screened from nine different wild and cultivated varieties of pulses. Insect feeding bioassay with C. maculatus revealed that seven of these seed varieties were not infested by the bruchid insect pest. Additionally, the presence of arcelin polypeptide subunits (27–42 kDa) was demonstrated in the seeds of Phaseolus limensis L. and Phaseolus lunatus L. whereas, an insignificant amount was observed in Lablab purpureus L. Besides, seed kernel extract of P. lunatus registered a highest HA activity against native human-A erythrocytes and this activity was increased to several fold when the erythrocytes were treated with proteolytic enzymes revealing the characteristic feature of arcelin. Similarly, HA activity was observed when rat and mouse erythrocyte was treated with pronase, whereas, no titer value was observed upon treatment with its native erythrocytes. Of the 24 carbohydrates tested, only acetylated amino sugar, N-acetyl-d-galactosamine inhibited the agglutinating activity of crude seed extract against human-A RBC. Among the three glycoproteins tested, none were found potential to competitively inhibit the agglutination activity against human-A erythrocytes. Overall, this study reveals the presence of arcelin, an anti-metabolic insecticidal protein in seeds of P. lunatus.     

Protein Hydrolysates from Shrimp (Metapenaeus dobsoni) Head Waste: Optimization of Extraction Conditions by Response Surface Methodology

Utilization of shrimp head waste from the processing industry offers a solution to environmental pollution and also produces valuable bioactive peptides. The present study was aimed to optimize the alcalase assisted extraction conditions by response surface methodology (RSM) to obtain protein hydrolysates from shrimp (Metapenaeus dobsoni) head waste with maximum antioxidant activity. Based on the models derived by RSM, the optimized conditions for maximum degree of hydrolysis (DH) were pH 8.2, temperature of 45.4°C, and enzyme/substrate (E/S) of 1.8%. Meanwhile, the optimized conditions for maximum antioxidant activity of protein hydrolysates as measured by 2, 2-diphenyl-1-picrylhydrozyl (DPPH) and ferric reducing antioxidant power (FRAP) assays were pH 8.2 and 8.1, temperatures of 49.7 and 59.4°C, and E/S of 2.1 and 2.7%, respectively. The maximum predicted values for DH, DPPH, and FRAP were 42.44%, 39.64% inhibition, and 8.3 μM Fe (II)/g wet wt. of sample, respectively. The extraction of protein hydrolysates at optimal conditions derived by these models resulted in DH, DPPH, and FRAPs of 40.31%, 38.93%, and 8.21 μM Fe (II)/g of sample, respectively, demonstrating the fitness of the models. The present study demonstrates the potential of Metapenaeus dobsoni head waste as a source of protein hydrolysates with prospective antioxidant activity.     

Sudden cardiac death in a dog during Holter recording—R on T phenomenon

A 6-year-old castrated male Golden Retriever was diagnosed with severe subaortic stenosis with severe left atrial enlargement and high heart rate due to atrial fibrillation. Treatment with digoxin and diltiazem to control ventricular response rate was initiated. Ambulatory electrocardiographic monitoring (Holter monitoring) was performed at the beginning of treatment and was repeated to evaluate the patient's response to drug therapy. Drug dose adjustments were made based on response to therapy as assessed by Holter monitoring. The dog experienced sudden death at home 19 days after beginning treatment while wearing the Holter monitor. Analysis of the Holter recording revealed marked increase in number and complexity of ventricular arrhythmias. A ventricular premature complex occurring on a T wave (R on T) was noted preceding the polymorphic ventricular tachycardia. This arrhythmia immediately degenerated into ventricular fibrillation followed by asystole. This case report describes the arrhythmia that preceded cardiac arrest and reviews the risk factors that could have potentiated the fatal arrhythmia in this dog.     

Neem oil as a potential seed dresser for managing Homopterous sucking pests of Okra (Abelmoschus esculentus (L.) Moench)

Insecticidal seed treatment is an alternative method to spray and granular applications. It can protect the crop right from germination to reproductive stage. Recurrent use of chemical insecticides destabilizes the ecosystem and enhances the development of resistance in pest population. Use of biopesticides like neem oil (NO) is a promising one in this situation. Two field experiments were conducted to test the efficacy of NO as a seed dresser (20 ml kg⁻¹) and the effect was compared with systemic chemical insecticides imidacloprid (7 g kg⁻¹) and carbosulfan (7 g kg⁻¹) and Pseudomonas fluorescens (10 g kg⁻¹). Field studies revealed that the neem oil 60EC (C) (NO 60EC (C)) recorded minimum population of sucking pests Leafhopper—Amrasca biguttula biguttula Ishida and Aphids—Aphis gossypii Glover (Homoptera: Cicadellidae and Aphididae), i.e., below the ETL (2 number per leaf) up to 45 days after sowing and provided better yield compared to control. Although the systemic chemical insecticide imidacloprid performed better by recording 11,280 and 11,580 kg ha⁻¹ of marketable fruit yield, NO 60EC (C) also recorded about twofold increase in marketable fruit yield 11,000 and 10,620 kg ha⁻¹, respectively, in 2001 and 2002 experiments. Results of this study suggest that NO could be used as a potential seed dresser for managing sucking pests in okra.     

Effect of combined inoculation of Azospirillum and Rhizobium on nodulation and N2-fixation of winged bean and soybean

Different strains of winged bean and soybean Rhizobium were tested with several strains of Azospirillum for combined inoculation in winged bean and soybean under temperate and tropical conditions.Substantial increases in nodulation, N₂-fixation, shoot dry matter production and N-gain due to the mixed inoculation were obtained in some combinations of these bacteria.The response to combined inoculation was mainly dependent upon the genotypes (strains) of these organisms. The influence of Rhizobium-genotype in expressing the associative effect was more decisive than that of Azospirillum. Cell-free extract of Azospirillum produced the same effect as that of the organism itself, while the culture supernatant also showed the same in some instances. The cell-free extract of Azospirillum strain KUL-X considerably reduced nodulation, N₂-fixation and N-gain of the Rhizobium strain RRIM-56, which was not otherwise affected by mixed inoculation. The combination of Azospirillum strain KUL-Y and Rhizobium strain KUL-BH produced the highest values of nodulation, N₂ - fixation and N-gain of all the Azospirillum—Rhizobium combinations in winged bean.     

In vitro studies on the selective cytotoxic effect of crocetin and quercetin

Crocetin (5-20 microg/ml), quercetin (10-40 microg/ml), and cisplatin (60-180 microg/ml) used as a positive control drug, were tested against human rhabdomyosarcoma (RD) cells and African green monkey kidney (Vero) cells. The cell viability, morphological changes, and lactate dehydrogenase activity were assessed. RD cell growth was found to be inhibited dose dependently by the three tested compounds. Morphological observation by phase contrast microscopy revealed that both crocetin and quercetin caused intense damage only on the malignant (RD) cells, whereas mild toxic effect was seen with cisplatin also on normal (Vero) cells.     

Estimating carbon sequestration potential of existing agroforestry systems in India

India launched National Agroforestry Policy on 10th February, 2014 which has the potential to substantially reduce poverty in rural India and revive wood based industry, besides integrating food production with environmental services. The policy is not only crucial to India’s ambitious goal of achieving 33 per cent forest and tree cover but also to mitigate GHG emissions from agriculture sector. Dynamic CO2FIX-v3.1 model has been used to estimate the carbon sequestration potential (CSP) of existing agroforestry systems (AFS) for simulation period of 30 years in twenty six districts from ten selected states of India. The observed number of trees on farmers’ field in these districts varied from 1.81 to 204 per hectare with an average value of 19.44 trees per hectare. The biomass in the tree component varied from 0.58 to 48.50 Mg DM ha^?1, whereas, the total biomass (tree and crop) ranged from 4.96 to 58.96 Mg DM ha^?1. The soil organic carbon ranged from 4.28 to 24.13 Mg C ha^?1. The average estimated carbon sequestration potential of the AFS, representing varying edapho-climatic conditions, on farmers field at country level was 0.21 Mg C ha^?1yr^?1. At national level, existing AFS are estimated to mitigate 109.34 million tons CO₂ annually, which may offsets one-third (33 %) of the total GHG emissions from agriculture sector.