Bacteriophagy in the Developing Chick Embryo

Abstract

The chorio-allantoic membrane of chick embryos was employed for in vivo bacteriophage studies. A dysentery phage containing 3 types was selected. The culture of Shigella paradysenteriae used, was lysed by high dilutions of this phage for 72 hrs.; then a secondary culture resistant .to one of the types appeared. In all, 83 eggs with actively motile 10-day embryos were inoculated with a 0.1 ml. of a diluted broth culture (approx. 500 organisms). After 5 hrs. incubation, 44 of the eggs were given 0.1 ml. of bacteriophage; the 39 controls were given broth alone. 32 of the embryos treated with phage survived the 6-day exptl. period; all but one of the controls died in 3 days. Culture and bacteriophage detns. were made on the mixture of yolk and membrane fluid. The secondary culture mentioned above was isolated from those phage treated eggs which died. Some survivors also carried this secondary culture. The titer of bacteriophage dropped in the eggs with dead embryos; there was multiplication of phage in those that survived. Evidently chick embryos are a favorable medium for in vivo study of bacteriophagy.