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Cytotoxicity by anthracycline antibiotics is attributed to several pathways. Important among them are formation of free-radical intermediates. However, their generation makes anthracyclines cardiotoxic which is a concern on their use as anticancer agents. Hence, any change in redox behavior that address cardiotoxicity is welcome. Modulation of redox behavior raises the fear that cytotoxicity could be compromised. Regarding the generation of free radical intermediates on anthracyclines, a lot depends on the surrounding environment (oxic or anoxic), polarity and pH of the medium. In case of anthracyclines, one-electron reduction to semiquinone or two-electron reduction to quinone-dianion are crucial both for cytotoxicity and for cardiotoxic side effects. The disproportion-comproportionation equilibria at play between quinone-dianion, free quinone and semiquinone control biological activity. Whatever is the form of reduction, semiquinones are generated as a consequence of the presence of anthracyclines and these interact with a biological target. Alizarin, a simpler anthracycline analogue and its Mn II complex were subjected to electrochemical reduction to realize what happens when anthracyclines are reduced by compounds present in cells as members of the electron transport chain. Glassy carbon electrode maintained at the pre-determined reduction potential of a compound was used for reduction of the compounds. Nucleobases and calf thymus DNA that were maintained in immediate vicinity of such radical generation were used as biological targets. Changes due to the generated species under aerated/de-aerated conditions on nucleobases and on DNA helps one to realize the process by which alizarin and its Mn II complex might affect DNA. The study reveals alizarin was more effective on nucleobases than the complex in the free radical pathway. Difference in damage caused by alizarin and the Mn II complex on DNA is comparatively less than that observed on nucleobases; the complex makes up for any inefficacy in the free radical pathway by its other attributes.

Blast disease of rice is generally considered the most important rice disease worldwide for its extensive distribution and also for its destructiveness under favourable environmental conditions. The disease incidence and development in time scale in relation to different parameters can be predicted through epidemiological study. Plant disease forecasting is a management system used to predict the occurrence or change in severity of plant diseases. A field experiment was conducted for three consecutive year in kharif season at two different sampling sites in North 24 Parganas, W est Bengal to find out the effect of meteorological factors on severity of blast disease. The aim of the present study is to prepare models for predicting the severity, with the aim of helping to prevent or at least mitigate the spread of blast disease. For forecasting of disease severity, the comparative study of three years meteorological data was made. The congenial weather conditions for the infection of blast disease pathogen viz. Pyricularia oryzae was recorded. The crop phases during which rapid development of disease takes place were also recorded. Multiple regression analysis (MRA) of PDI values with the age of the plant, respective pathogenic spore concentration and with five meteorological parameters was performed. From step down equation, it was found that if the age of the plant and airborne spore concentration, RH and rain fall are increased, disease severity also increases significantly in both the seasons. From Cumulative logit model the covariates with their odds ratios were determined. From all the findings it can be concluded that among meteorological parameters high relative humidity, rain fall and comparatively low temperature are the common factor for disease incidence and severity.

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