Adhesion of cholera phage to glass surfaces at high inactivation temperatures.

Decimal dilutions of cholera phage heated in test tubes at the temperature range of 65 degrees to 70 degrees showed an erratic behaviour in that the residual counts had no relationship to the quantity of phage originally present in the tubes. If the contents of the heated tubes were decanted off and the empty tubes washed repeatedly with broth, the recovery of phage from successive washings of the tubes was much higher than what would be expected on the basis of the simple dilution effect of washings. The data presented indicate that the heating causes loose adhesion of phage to the wall of the glass tubes from where they can be detached by washing or shaking. The facts that E. coli phage T1 and also cholera phages tested with two different broths have given similar results, suggest that some general property of the phage itself is responsible for the phenomenon observed. The phenomenon appears to be different from the adsorption of phage to glass filters at lower temperature range described by earlier workers.

Thermal inactivation of cholera phages.

Thermal inactivation of seven cholera phages have been tested over the temperature range between 50 degrees to 70 degrees C. It was found that the phages vary widely in their heat sensitivity, Mukerjee's phages III being the most sensitive of the whole group. With all the phages over the temperature range studies, the inactivation curve seem to follow the pattern of virus thermal inactivation in general, the inactivation proceeding initially at a rapid rate, which in about 15 minutes time, gradually changes to a slower rate, each component tending to follow kinetics of the first order. The difficulty of explaining this phenomenon on the basis of population heterogeneity has been discussed.