The Stability of Bacterial Viruses in Solutions of Salts

Abstract

Burnet and McKie (1) in 1930 published a report on balanced salt action as manifested in bacteriophage phenomena. They found that coli and staphylococcal bacteriophages when diluted in 0.1 N solutions of sodium, potassiam, and ammonium salts were much more susceptible to the inactivating effects of temperature (60°C.) than were the same phages diluted in broth. The addition of a small amount of calcium, magnesium, or barium salt partially or completely prevented this inactivation. They interpreted this phenomenon as another example of the physiological ion antagonism studied by Ringer, Jacques Loeb, and many other physiologists. Gratia (2) has drawn similar conclusions from experiments on the stability of a megatherium phage in salt solutions.In a study of the properties of the coli-dysentery phages in chemically defined media we have found that these phages exhibit a similar phenomenon, which, however, cannot be explained on the basis of ion antagonism. The present paper is a report on the kinetics of inactivation of phages in the presence of various ions and on the effect of the environment on the rate of inactivation. Materials and MethodsThe group of seven coU-dysentery phages studied by Demerec and Fano 0) was used. Certain properties of this group of bacterial viruses have been summarized by Delbriick (4). These phages were grown on Escherichia coli, strain B, in a chemically defined medium containing per liter 1 gin. NH4CI, 0.1 gin. MgSO~, 1.5 gm. KH~PO4, 3.5 gin. Na~HPO4, and 9 gm. lactic acid. The medium was adjusted to pH 6.5 by the addition of NaOH. Since phage T5 is not produced in the absence of calcium ion, calcium chloride to a final concentration of 0.001 ~x was added when preparing stocks of this phage. All phage stocks used contained between 10 ° and 101° plaque-forming particles per ml. All phage assays were made on strain B of E. coli using the agar layer technique of Gratia as modified by Hershey (5). The plating medium was Difco nutrient agar to which 0.5 per cent of sodium chloride was added. The broth used in certain experiments was Difco nutrient broth with 0.5 per cent of sodium chloride. The pH of these broth-containing media was 6.8.All glassware used in this study was cleaned with acid dichromate and repeatedly rinsed with hot distilled water since, as will be shown later, very small amounts of * Aided by a grant from the

Uncoupling Phosphorylation in Spinach Chloroplasts by Absence of Cations

“…Mitochondria ( 15) bacteriophages ( 1,13,16) and bacterial protoplasts (11,12,15) are damaged in the al)sence of cations, and protected from damage when cations are present. In these other systems monovalent ions (lo not seem to be effective, and often spermine and sperimidine are unusually effective protective agents.…”

The Heat Inactivation of Vaccinia Virus

“…Adams (1949) found that the inactivation of bacteriophage by heat was exponential, and increased very rapidly over the 10" range from 63" to 73'. Bronson and Scott & Lauffer (1946) were unable to show that influenza virus haemagglutinin was destroyed as a first-order reaction when heated.…”

The Influence of Some Metal Ions and pH on the Inactivation of Vaccinia Virus by Heat

“…Several authors (Burnet & McKie, 1930;Adams, 1949;Lark & Adams, 1953;Northrop, 1955) have shown that the heat stability of bacteriophage suspensions depends on the concentrations of cations in the suspending fluids. Stability was generally increased when small concentrations of divalent cations were added to a basic concentration of monovalent cation, although monovalent cations by themselves conferred less protection than distilled water (Burnet & McKie, 1930).…”