Isolation and characterization of restriction endonuclease in Plesiomonas shigelloides and Aeromonas species

Five restriction endonucleases (ENases) and one ENase were found in a screen of 196 strains of Plesiomonas shigelloides and 147 strains of Aeromonas species. Plesiomonas and Aeromonas species are classified as Vibrionaceae, identified as food-poisoning bacteria, are closely genetically related to each other, and their ENases producing abilities have not bee reported. ENases were detected at relatively low frequencies in these species as compared to those in other species, such as Salmonella species and Vibrio parahaemolyticus. All Enases were shown to be isoschizomers of already known ENases. One of the Plesiomonas ENases, designated PshBI, recognizing the sequence 5'-AT/TAAT-3' should be useful, since PshBI ENase is produced at a high yield of 7000 units/g of wet cells. The specificities of other ENases are also described in this paper.