Human neutrophil peptide defensins induce single strand DNA breaks in target cells

To investigate whether target cell DNA injury participates in cytolysis by human neutrophil defensins (HNP), we analyzed HNP-treated cells for single strand breaks by the alkaline unwinding assay and the activation of ADPribose polymerase, a DNA repair enzyme. Strand breaks and ADP-ribosylation were first detected in K562 and Raji targets 6-8 hr after incubation with HNP and increased to maximal levels by 18 hr. DNA was not degraded into nucleosome-sized fragments. To assess the impact of DNA injury on cytolysis, we increased strand breakage by coincubating targets with HNP and two inhibitors of ADPribose polymerase, 3-aminobenzamide, or nicotinamide. Concurrently with inhibiting polymerase activity and increasing DNA injury, these agents significantly enhanced HNP-mediated cytolysis. Enhancement occurred only at time points (over 6 hr) and in targets (only nucleated targets) where HNP-induced DNA injury could be occurring. These data indicate that neutrophil defensins can induce DNA injury in targets and suggest such injury may be involved in target cell death.     

Isolation of autosomal mutations in Drosophila melanogaster without setting up lines

Summary Mutants of Drosophila melanogaster are being used increasingly for studying different biological mechanisms. However, most attempts to identify new mutations have been restricted to the X-chromosome. It has been very difficult to identify new loci on the autosomes, as recessive mutations have to be made homozygous by setting up independent cultures for each mutagenized chromosome. We introduce a mutagenesis scheme which does not require setting up independent cultures. It uses meiotic recombination in compound autosomes to make recessive mutations homozygous and allows the screening of tens of thousands of mutagenized chromosomes with relatively little effort. In a pilot experiment, we tested about 33,300 chromosomes for temperature-sensitive paralytic mutations. We obtained 62 independent paralytic mutations and a large number of other mutations. Eight out of 25 of the paralytic mutations are on the autosomes. This method makes autosomes, which constitute about 80% of the Drosophila genome, more accessible for mutational analysis of various biological mechanisms.     

Protective effect of glutathione and selenium against alloxan induced lipid peroxidation and loss of antioxidant enzymes in erythrocytes

Alloxan is a diabetogenic drug and is known to induce diabetes through generation of free radicals. The toxic oxygen species can be detoxified by antioxidant enzyme system and thus reduce the deleterious effect of lipid peroxidation. Erythrocytes exposed to alloxan induced lipid peroxidationin vivo as well asin vitro. Although alloxan treatment produced a deleterious effect on antioxidant enzymes, pretreatment with glutathione and selenium led to a recovery of the activities of superoxide dismutase and glutathione peroxidase. However, catalase activity increased on alloxan treatment. Alloxan reduced blood glucose level significantly within 60 min but thereafter a slow and steady rise was observed.     

Selection of a substratum for composing biofilm system of a textile-effluent decolourizing bacteria

Summary Some abundantly and cheaply available substrates were used to develop biofilms of textile-effluent decolourizing bacteria. These biofilm systems were compared for their decolourization efficiency in packed bed system. Biofilm systems using mineral material, sea-shells or nylon web as substratum decolourized effluent (100%) in 9 –12 h without major release of free cells into the medium.     

Blinded sample size recalculation in multiple composite population designs with normal data and baseline adjustments

The increasing interest in subpopulation analysis has led to the development of various new trial designs and analysis methods in the fields of personalized medicine and targeted therapies. In this paper, subpopulations are defined in terms of an accumulation of disjoint population subsets and will therefore be called composite populations. The proposed trial design is applicable to any set of composite populations, considering normally distributed endpoints and random baseline covariates. Treatment effects for composite populations are tested by combining p-values, calculated on the subset levels, using the inverse normal combination function to generate test statistics for those composite populations while the closed testing procedure accounts for multiple testing. Critical boundaries for intersection hypothesis tests are derived using multivariate normal distributions, reflecting the joint distribution of composite population test statistics given no treatment effect exists. For sample size calculation and sample size, recalculation multivariate normal distributions are derived which describe the joint distribution of composite population test statistics under an assumed alternative hypothesis. Simulations demonstrate the absence of any practical relevant inflation of the type I error rate. The target power after sample size recalculation is typically met or close to being met.     

Involvement of Asada-Halliwell Pathway During Phytoremediation of Chromium (VI) in Brassica juncea L. Plants

Brassica juncea (Indian mustard) L. plants were exposed to different concentrations (0.0, 0.1, 0.3 and 0.5 mM) of Chromium (Cr) and harvested after 30 and 60 days of sowing for the analysis of growth parameters, metal uptake and oxidative stress markers. Significant accumulation of Cr (VI) by B. juncea L. plants resulted in the reduced growth and modulations in the pool of various biochemical stress markers. The toxic effects of Cr (VI) on growth and other stress markers (protein content, lipid peroxidation and antioxidative enzymes viz.SOD, CAT, POD, APOX, GR, DHAR and MDHAR) in B. juncea L. were observed to be concentration and time dependent. Effect of Cr (VI) on biochemical parameters was differential and their maximum activities of SOD, POD, APX, GR, DHAR and lipid peroxidation were recorded at 0.5 mM concentration in 30 days old plants. Whereas, trend in the activities of most of the stress markers was reversed in 60 days old plants. The results obtained from the study suggested that Cr (VI) stress inhibited growth of B. juncea L. plants is directly interrelated with its accumulation and resulted in the modulation in activities of various stress markers.