Characterization of Trypsin Like Protease from <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> (Hubner) and Its Potential Inhibitors

Helicoverpa armigera is the most devastating pest of important crops causing heavy yield losses. The larval midgut harbours proteases and their inhibition starves insects to death or may disrupt their normal metabolism. So there is need to characterize gut protease and its potential inhibitors. A serine protease (trypsin like) from H. armigera gut was purified ~37 folds with 22 % yield and its molecular weight was found to be ~18.8 kilo Dalton. The Michaelis constant using N-α-benzoyl-DL-arginine-p-nitroanilide as a substrate was 0.31 mM. Maximum reaction rate was determined to be 3.47 nmol p-nitroaniline/min. Free energy of binding was found to be ?20.8 kJ/mol. The optimum temperature of enzyme was found to be 50 °C and around 17 % activity was maintained on heating at 80 °C for 30 min. The optimum pH for trypsin like activity was 11 with wide range of activity between 9 and 12 indicating that midgut digestive trypsin of H. armigera is active over wide range of alkaline pH. Metal ions Cu²⁺, Zn²⁺, Cd²⁺ and Hg²⁺ were found to have the potential to inhibit the enzyme. Maximum inhibition was observed with Cu²⁺ (73 %) and minimum inhibition with Cd²⁺ (47 %). Copper inhibited trypsin non-competitively and zinc inhibited uncompetitively. Ascorbic acid, EDTA, leupeptin and benzamidine were found to be competitive inhibitors of H. armigera gut protease. The K_i values for Cu²⁺, ascorbic acid, EDTA, leupeptin and benzamidine were found to be 1.32, 38.23, 2.51 mM, 37.13 µM and 5.66 mM respectively.     

Erratum

Simian virus 40 (SV40) large tumor (T) antigen was isolated from SV40-infected permissive and -transformed cells by immunoprecipitation with anti-T sera and purified by electrophoresis on solubilizable SDS-polyacrylamide gels. This method proved to be a rapid and efficient procedure for purifying T antigen as 74% of the immunoprecipitated T antigen was subsequently recovered. The purified, SDS-denatured large T antigen retained its ability to react with anti-T antibody and to immunize mice against a challenge of syngeneic SV40 tumor cells, indicating that the antigenic sites present on the large T antigen molecule that induce a tumor rejection response in vivo are resistant to denaturation by SDS.     

Evaluation of vitreoretinal interface changes in patients receiving intravitreal anti-VEGF therapy

Purpose

To study the effects of repeated intravitreal injection of anti-VEGF drug bevacizumab on the vitreoretinal interface (VRI).

Methods

Patients undergoing intravitreal injection of bevacizumab were enrolled. Eyes with media haze, uveitis, high myopia, history of cataract surgery or laser capsulotomy in last 6 months and complicated pseudophakia were excluded. VRI evaluation was done monthly for a minimum of 6 months. The nature and timing of the change(s) event was recorded.

Results

A total of 100 eyes were evaluated. Thirty-seven eyes developed new vitreoretinal interface change event (VICE). Pseudophakia (OR = 5.23, 95% CI = 1.99–14.07, p = 0.001), pre-injection VRI abnormality (OR = 2.63, 95% CI = 1.13–6.14, p = 0.024) and older age at enrollment (62.6 ± 13.9 vs. 56.3 ± 14 years) were risk factors for development of VICE. Eighty percent of interface events occurred in the first 3 months of therapy. Eight needed surgical intervention for consequences of vitreoretinal separation.

Conclusion

VICE is not infrequent in eyes receiving anti-VEGF therapy though rarely need surgical intervention. The first 3 months are the critical months to watch out for these events. The treating ophthalmologists must keep the risk factors for development of in mind and monitor and counsel patients accordingly.

     

Abiotic Stress Tolerance of Chickpea Genotypes Depends Upon Antioxidative Potential and Nutritional Quality of Seeds

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Seeds of thirty chickpea genotypes were evaluated for their stress tolerance capacity and nutritional status....     

Radiation dose of CT coronary angiography in clinical practice: objective evaluation of strategies for dose optimization

Background

CT coronary angiography (CTCA) is an evolving modality for the diagnosis of coronary artery disease. Radiation burden associated with CTCA has been a major concern in the wider application of this technique. It is important to reduce the radiation dose without compromising the image quality.

Objectives

To estimate the radiation dose of CTCA in clinical practice and evaluate the effect of dose-saving algorithms on radiation dose and image quality.

Methods

Effective radiation dose was measured from the dose-length product in 616 consecutive patients (mean age 58 ± 12 years; 70% males) who underwent clinically indicated CTCA at our institution over 1 year. Image quality was assessed subjectively using a 4-point scale and objectively by measuring the signal- and contrast-to-noise ratios in the coronary arteries. Multivariate linear regression analysis was used to identify factors independently associated with radiation dose.

Results

Mean effective radiation dose of CTCA was 6.6 ± 3.3 mSv. Radiation dose was significantly reduced by dose saving algorithms such as 100 kV imaging (−47%; 95% CI, −44% to −50%), prospective gating (−35%; 95% CI, −29% to −40%) and ECG controlled tube current modulation (−23%; 95% CI, −9% to −34%). None of the dose saving algorithms were associated with a significant reduction in mean image quality or the frequency of diagnostic scans (P = non-significant for all comparisons).

Conclusion

Careful application of radiation-dose saving algorithms in appropriately selected patients can reduce the radiation burden of CTCA significantly, without compromising the image quality.     

Apple flavonols and n-3 polyunsaturated fatty acid–rich fish oil lowers blood C-reactive protein in rats with hypercholesterolemia and acute inflammation

Both quercetin glycosides and omega-3 polyunsaturated fatty acids (n-3 PUFA) are well established for their individual health benefits in ameliorating metabolic disease. However, their combined effects are not well documented. It was hypothesized that the beneficial properties of quercetin glycosides can be enhanced when provided in combination with n-3 PUFA. Therefore, the aim of the present study was to investigate the effects of apple flavonols (AF) and fish oil (FO), alone and in combination, on proinflammatory biomarkers and lipid profiles in rats fed a high-fat diet. Sixty male Wistar rats were randomly divided into 5 groups (n = 12) and fed a high-fat diet for 4 weeks. One of the 5 groups of rats was used as the high-fat control. The other 4 groups of rats were injected with lipopolysaccharide (LPS) (5 mg/kg body weight) intraperitoneally, 5 hours before euthanization. One of these 4 groups was used as the hypercholerolemic and inflammatory control (high-fat with lipopolysaccharide [HFL]), and the other 3 received AF (HFL + 25 mg/kg per day AF), FO (HFL + 1 g/kg per day FO), or the combination (HFL + AF + FO). Compared to the HFL group, the AF, FO, and AF + FO groups showed lower serum concentrations of interleukin-6 and C-reactive protein (CRP) levels. The AF, FO, and AF + FO also had lowered serum triacylglycerol and non–high-density lipoprotein cholesterol (HDL-C) concentrations, but higher HDL-C levels relative to the HFL group. An additive effect was observed on serum CRP in the AF + FO group as compared with the AF or FO groups. The results demonstrated that AF and FO inhibited the production of proinflammatory mediators and showed an improved efficacy to lower serum CRP when administered in combination, and they significantly improved blood lipid profiles in rats with diet-induced hyperlipidemia and LPS-induced acute inflammation.