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The newly developed DNA-biosensor is a very promising tool for the investigation and study of the action of drugs specifically designed to interact with DNA. In this work the electrochemical reduction of nitroimidazole drugs was studied in the presence of DNA immobilized onto the surface of a glassy carbon electrode. This enabled preconcentration of the drug onto the electrode surface, which was then electrochemically reduced to the corresponding hydroxylamine which followed by reoxidation give the nitroso compound and subsequently an azoxycompound. Moreover, as the target of the nitroimidazole action was the DNA, the damage caused to DNA on the electrode surface by a reduction product of this drug could be detected in situ.

A bacterial disease causing stalk rot of maize was observed in Portugal, during the summer of 1991, in overhead sprinkler-irrigated fields. Affected plants showed symptoms of a soft rot disease and isolations made from infected tissues consistently yielded a bacterium. On the basis of morphological, cultural, biochemical, physiological and pathological properties, the pathogen was identified as Erwinia chrysanthemi. According to biovar discrimination tests, the maize isolates were allocated to biovars 2 and 3 of E. chrysanthemi.