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An investigation of the potential role of the reduced cofactor NADH in the regulation of the expression of the adhE gene, the encoder of the fermentative alcohol dehydrogenase of Escherichia coli, gave indications that the enzymatic activity of the AdhE protein regulates the level of NADH under anaerobic conditions, thus indirectly regulating its own expression. The expression of the adhE gene correlated with the ratio of NADH to NAD.

The regulation of the adhE gene, which encodes the fermentative alcohol dehydrogenase (ADH) of Escherichia coli, was investigated by using gene fusionsand by two-dimensional protein gel electrophoresis. The induction under anaerobic conditions of the adhE protein and its overproduction in regulatory mutants were demonstrated. The results indicate that the induction of ADH underfermentative conditions is due to the synthesis of increased levels of protein and that anaerobic regulation is at the transcriptional level.

A variety of borate glass compositions are shown to be effective in inhibiting bacterial growth on their surfaces. Both Gram-negative (Escherichia coli and Salmonella typhimurium) and Gram-positive bacteria (Stapphylococcus aureus) were effectively killed by lithium borate and lithium potassium borate glasses of high and low alkali contents. The surface environment was shown to become acidic for low metal contents, halting growth, and alkaline for higher metal contents. The alkaline surface layer proved to be more efficient in eliminating bacteria. The more alkaline sample also appeared to act especially rapidly in preventing growth. Micro-Raman measurements were taken to characterize the surface layer responsible for the bacterial inhibition. [ABSTRACT FROM AUTHOR]