No abstract

Oxidative stress was found to have a role in many viral diseases including AIDS, hepatitis and influenza. In the present study the pathology of influenza viral infection in the lungs, which may lead to oxidative stress, was investigated and an attempt was made to study the efficacy of anti-oxidants as therapeutic agents. Adult male mice of Swiss albino type were infected with influenza virus (A/Hong Kong/8/68) and studied for the antioxidant status in the lungs by evaluating the lung enzymatic anti-oxidant system including superoxide dismutase and catalase. Superoxide radical generation, which might increase by the activated alveolar macrophages, was estimated by nitroblue-tetrazolium reduction assay. We have also estimated lipid peroxidation levels in lung through thiobarbutiric acid reactive substances assay. We also examined the ability of flavonoid quercetin in protecting from influenza virus-induced oxidative stress. The influenza-infected group showed decreased levels of superoxide dismutase and catalase; however, anti-oxidant supplemented groups showed these activities to be the same as in the control group. The lipid peroxide levels were increased in virus-infected mice. Administration of quercetin lowered the lipid peroxide levels significantly. Formazan positive cells were increased by 80% in the virus-infected group and supplementation with quercetin reduced their number to 44%.

No abstract

Xanthan is an heteropolysaccharide produced by Xanthomonas campestris. Xanthan gum fermentation by a local isolate of X. campestris using different carbon sources was studied. The production of polysaccharide was in¯uenced by the carbon source used. The production of the xanthan was 15.654 g/l with synthetic medium. Production of xanthan at various temperatures ranging between 25°C and 40°C was studied. The growth and production was maximum between 25±30°C. Xanthan production was maximum at pH 7.0±7.5.

Two mutant strains of Amycolatopsis mediterranei VA17 and VA18 were isolated using physical (UV) and chemical (NTG) mutagens gave high rifamycin B than the parent type when grown in the same fermentation medium with a pH of 7.2, temperature 32°C for a period of 12 days. The cultural conditions of both mutant strains are similar to the parent strain except temperature which was higher by 4°C. By this mutation and selection study, rifamycin B production was improved from 1400 mg/l to 2450 mg/l.