Bioactivities of caffeic acid methyl ester (methyl-(E)-3-(3,4-dihydroxyphenyl)prop-2-enoate): a hydroxycinnamic acid derivative from Solanum melongena L. fruits

Feeding deterrent and growth inhibitory effects of caffeic acid methyl ester (CME) isolated from the fruit extract of eggplant, Solanum melongena L. along with two known phenolic acids, caffeic acid (CA) and chlorogenic acid (CG) and azadirachtin (taken as active control), were evaluated against Spodoptera litura Fab. and Achaea janata L. (Lep., Noctuidae). The structure of CME was determined on the basis of extensive spectroscopic (UV, FTIR, ¹H, and ¹³C NMR) data analysis. CME has exhibited strong feeding deterrent activity against S. litura and A. janata larvae with ED₅₀ values of 52.02 and 41.02 μg/cm² leaf area, respectively. CA and CG were relatively less effective compounds when compared with CME. The results also revealed that the isolated compound CME caused marked larval growth inhibition in S. litura and A. janata larvae after 7 days of feeding on a treated diet. The effect on growth of larvae was concomitant with the reduced feeding and digestibility of ingested food. So the activities of digestive proteases within the midgut of larvae were examined using specific substrates to understand the digestive physiology in the larval guts. The bulk of the activity was associated with serine proteases comprising trypsin-, chymotrypsin-, and elastase-like enzymes, which decreased in diets containing CME, whereas, interestingly increased with CG. From the results, we conclude that CME isolated from S. melongena fruit extract shows feeding deterrent and larval development inhibitory activities that may prove useful in the management of S. litura and A. janata larvae.     

Design of a farm layout for irrigation with limited discharges

In order to improve the irrigation efficiencies of small farms employing cavity wells for their water supply, an experimental study was conducted at the Central Soil Salinity Research Institute, Karnal. The cavity wells of the Karnal region do not have any discharge regulating devices for improving the irrigation efficiencies. The only way of improving these efficiencies is by designing an efficient irrigation layout, so that uniform water application is accomplished. The present study involves field determination of the opportunity time at each point along the border from advance and recession curves and computing the depth of cumulative infiltration from the infiltration rate curve. The irrigation efficiencies are also calculated from soil moisture measurements made before and after each irrigation.The results of this study show that a realistic field assessment of the irrigated border efficiencies is obtained through a soil moisture measurement procedure. The procedure, based on opportunity time and infiltration, overestimates the irrigation efficiencies due to the empirical nature of the infiltration equation. For small farms, with a limited discharge of 10 l/s, an irrigation layout of borders of 50–70 m in length and 6–8 m in width is recommended.     

Influence of Solar Radiation and Vapour Pressure Deficit on Transpiration Efficiency of Rainfed Sorghum

Besides assimilation, plant water relations are important aspects of physiological basis of productivity of crops in water limited environment. The relationships of photosynthesis rate, transpiration rate, leaf water potential and stomatal conductance with photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) during pre-flowering (panicle initiation to ear emergence) and grain filling (from anthesis to maturity) stages of a sorghum hybrid (cv. CSH-6 ) grown under rainfed conditions were studied. Photosynthesis rate declined when PAR was above 1300 μmol m⁻² s⁻¹. during both the growth stages. Higher transpiration rate during grain filling stage at higher PAR caused the transpiration efficiency to be lower than during pre-flowering stage when PAR was above 1200 μmol m⁻²s⁻¹.Leaf water potential and stomatal conductance decreased with increase in PAR. Leaf water potential was higher during pre-flowering than during grain filling stage but maximum photosynthesis rate was similar during both the growth stages. Changes in VPD did not qualitatively alter the relationships of the physiological variables with PAR.
Decreasing photosynthesis rate and LWP at high PAR suggest that photosynthesis rate was limited by low leaf water potential when PAR was optimal, and by low PAR even when leaf water potential was high in rainfed sorghum during rainy season.     

Characterization of carboxylesterase in skin mucus of Cirrhinus mrigala and its assessment as biomarker of organophosphate exposure

Presence of carboxylesterase (CbE) activity in the skin mucus of Cirrhinus mrigala was investigated. CbE activity in skin mucus showed higher substrate preference for α-naphthyl acetate over p-nitrophenyl acetate. Four CbE isozymes—CbE-1, CbE-2, CbE-3, and CbE-4 were observed in skin mucus during zymography. The isozyme CbE-4 was characterized as typical serine esterase, whereas CbE-1, CbE-2, and CbE-3 were identified as sulphhydryl group-dependent serine esterases. In vitro treatment of skin mucus with the organophosphorus insecticide, Nuvan^® showed strong inhibition of CbE activity. In vivo exposure of the fish to sublethal test concentrations (5 and 15 mg/l) of the insecticide also revealed significant inhibition of CbE activity in mucus. After the cessation of exposure, CbE activity recovered to its control level during the recovery periods. Thus, CbE activity in skin mucus could be considered a biomarker of the organophosphorus insecticide exposure to fish and a useful tool in monitoring environmental toxicity.     

Environmentally benign scouring of wool fibers using mesophile acidic lipase

Surfaces of raw wool fibers possess high amounts of greasy substances that need to be removed prior to further processing. Acidic lipases using Bacillus licheniformis (MTCC 2618) were produced with the optimum activity levels closer to the room temperature. Scouring of wool fibers using mesophile acidic lipase has been attempted, in the present work, as an alternative to the existing alkaline treatment and the samples were assessed in terms of weight loss, moisture regain, tenacity, elongation, surface appearance, and friction of the fibers. The lipase scoured wool fibers showed moisture regain and weight loss values comparable to that of alkaline treatment, with lower static and dynamic frictional coefficients. Higher tenacity and elongation values were observed in the lipase scoured fibers compared to the alkaline scoured samples and clear appearance of the surface, compared to the raw wool fibers, was also observed in the lipase scoured samples.     

Protective immune responses of recombinant VP2 subunit antigen of infectious bursal disease virus in chickens

Infectious bursal disease virus (IBDV) is the causative agent of Gumboro disease and poses a huge threat to poultry industry. The risks associated with conventional attenuated viral vaccines make it indispensable to probe into the development of novel and rationally designed subunit vaccines which are safer as well as effective. VP2 is the major host-protective antigen found in IBDV capsid. It encompasses different independent epitopes responsible for the induction of neutralizing antibody. Here, we report the efficacy of the immunodominant fragment of VP2 which induces both humoral and cellular immunity against infectious bursal disease. A 366bp fragment (52-417bp) of the VP2 gene from an IBDV field isolate was amplified and expressed in Escherichia coli as a 21kDa recombinant protein. The efficacy of rVP2(52-417) antigen was compared with two commercial IBDV whole virus vaccine strains. The rVP2(52-417) induced significantly high antibody titres in chicken compared to commercial vaccines and the anti-rVP2(52-417) sera showed reactivity with viral antigens from both commercial strains (P<0.0001) and field isolates. Also, the chicken splenocytes from rVP2(52-417) immunized group showed a significantly high proliferation (P<0.01) compared to other groups, which implies that the rVP2(52-417) fragment contains immunogenic epitopes capable of eliciting both B and T cell responses. Further, rVP2(52-417) conferred 100% protection against vIBDV challenge in the immunized chickens which was significantly higher (P<0.001) compared to 55-60% protection by commercial vaccine strains. Hence, the study confirms the efficacy of the immunodominant VP2 fragment that could be used as a potent vaccine against IBDV infection in chicken.     

Bioactivities of <Emphasis Type="Italic">Cocos nucifera</Emphasis> L. (Arecales: Arecaceae) and <Emphasis Type="Italic">Terminalia catappa</Emphasis> L. (Myrtales: Combretaceae) leaf extracts as post-harvest grain protectants against four major stored product pests

Compounds extracted from the leaves of coconut palm, Cocos nucifera L. (Arecales: Arecaceae) and the Indian almond, Terminalia catappa L. (Myrtales: Combretaceae) were assessed as potential grain protectants against four major pests of stored grains, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), and Callosobruchus chinensis (L.) (Coleoptera: Bruchidae). The crude leaf extracts and their fractions were obtained by solvent elution and bioassayed in the laboratory, focusing on (a) the duration of protection and (b) their effects on progeny production. Results showed that adults of C. chinensis, S. oryzae, and T. castaneum were equally susceptible to the fumigant toxicity of C. nucifera and T. catappa crude extracts as well as their column eluted fractions. On the contrary, adults of R. dominica showed tolerance to all the extracts tested in both fumigation and contact mode bioassays. Cocos nucifera crude extracts were highly effective in offering long-term protection in residual toxicity trials and along with the crude extracts of T. catappa showed strong repellent properties against the tested species except for R. dominica in a Y-tube olfactometer. Generally, the chromatographic fractions of crude leaf extracts eluted with ethyl acetate were significantly more effective than methanol, chloroform or hexane-eluted fractions. Further, all the tested plant extracts demonstrated a negative impact on several biological parameters such as feeding activity and progeny production of the tested species. These results highlight the potential of C. nucifera and T. catapa extracts as potent insecticides, feeding deterrents and progeny production inhibitors and consequently are suitable for the control of pests in stored commodities.     

Development of a radioimmunoassay procedure for aflatoxin B1 measurement

A radioimmunoassaay (RIA) procedure to measure aflatoxin B(1) (AfB(1)) in agricultural commodities was developed. AfB(1) oxime derivative was synthesized, characterized, and used for preparation of (125)I-labeled AfB(1). Antiaflatoxin B(1) serum was raised in-house using AfB(1)-bovine serum albumin conjugate as immunogen. The assay system was optimized in the range of 0.2-5 ng/mL, using a liquid phase (PEG) as well as a solid phase (coated polystyrene beads) separation system. Inter-assay and intra-assay variations, recovery, and parallelism studies validated the assay. AfB(1) analysis was carried out in nearly 130 samples of different agricultural commodities. The correlation coefficient was determined using commercial ELISA and in-house-developed RIA methods.