A Virus Lysing Halophilic Bacteria

Abstract

The study on a virus lysing halophilic bacteria is very interesting, as the synthesis of protein and nucleic acid at high salt concentration may be rather easily investigated.The halophilic bacterium we used is Bacillus circulans var. Yamada 107 strain, which grows optimally in the nutrient broth containing 5 / NaCI and can grow considerably well even in the medium containing 10% NaCI. Onishistrain of its bacteriophage was originally isolated from the soil obtained near our Institute.Pure culture of this strain was secured by six serial cultivations from isolated plaque on agar plates. A high titer phage stock solution (ca. 5 x 1010 phages/ml) was produced by means of the ordinary method. In the following experiments, the final concentration of mixed bacteria and phages were always ca. 5 x 108/ml, respectively. 1) Rate of adsorption One ml of 18 hours' bacterial culture containing 5 % NaCI (ca. 5 x 108 cells/ml) was added to each 9 ml of nutrient broth containing 3, 5, and 7 % NaCI respectively, and grown to a concentration of ca. 5 x 108 cells/ml at 37°C with aeration.Appropriate amounts of phage were added to this bacterial culture and the rate of adsorption was determined at known time intervals.