ISOLATION AND CHARACTERIZATION OF RESTRICTION-ENDONUCLEASE IN PLESIOMONAS-SHIGELLOIDES AND AEROMONAS SPECIES

Fine restriction endonucleases (ENases) and one ENase were found in a screen of 196 strains of Plesiomonas shigelloides and 147 strains of A evomonas species. Plesiomonas and Aeromonas species are classified as Vibrionaceae, identified as food-poisoning bacteria, are closely genet ically related to each other, and their ENases producing abilities hav e not been reported. ENases were detected at relatively low frequencie s in these species as compared to those in other species, such as Salm onella species and Vibrio parahaemolyticus. All ENases were shown to b e isoschizomers of already known ENases. One of the Plesiomonas ENases , designated PshBI, recognizing the sequence 5'-AT/TAAT-3' should be u seful, since PshBI ENase is produced at a higher yield of 7000 units/g of wet cells. The specificities of other ENases are also described in this paper.