RAPID SCREENING OF LACTIC-ACID BACTERIA FOR RESTRICTION-ENDONUCLEASE ACTIVITY

A rapid microscale heparin Sepharose CL-6B affinity gel procedure was developed for detecting restriction endonuclease (RE-Nase) activity in a variety of lactic acid bacteria. RE-Nase-containing extracts free o f DNA, RNA and nonspecific nuclease activity can be produced for forty or more strains daily and only 10-12 ml of each log phase culture was required for screening. RE-Nase activity was detected in several stre ptococci and lactobacilli. With appropriate modifications, this proced ure should allow rapid detection of RE-Nase activity in other bacteria l species.