Elder, Robert L. (Johns Hopkins University, Baltimore, Md.), and Roland F. Beers, Jr. Nonphotoreactivating repair of ultraviolet light-damaged transforming deoxyribonucleic acid by Micrococcus lysodeikticus extracts. J. Bacteriol. 90:681-686. 1965.-Extracts from Micrococcus lysodeikticus repair Haemophilus influenzae transforming deoxyribonucleic acid (DNA) damaged by ultraviolet light radiation. The repair is demonstrable over a wide dose range, with a constant dose reduction factor for a given concentration of DNA. The active component in the crude extract may be separated into a heat-stable dialyzable and a heat-labile nondialyzable component. The dialyzable fraction contains at least one component which appears to limit the maximal level of repair. Mg(2+) ions are required for the repair process.