Effects of type A botulinus toxin on primary chick embryo cell culture.

Type A botulinus toxin was studied for its ability to inhibit the DNA, RNA, and protein synthesis of a chick embryo primary cell culture. 3H-thymidine, 3H-uridine, and 14C-leucine were employed as tracers for measuring the synthesis of DNA, RNA, and protein, respectively. In the presence of large doses (2 x 10(6) MLD/ml) of type A botulinus toxin, RNA synthesis was inhibited to a lesser extent than DNA synthesis, and a very weak inhibition of protein synthesis was observed. The effect of type A botulinus toxin on DNA synthesis of a chick embryo brain cell suspension culture was also tested. The DNA synthesis of the brain cells was strongly inhibited by this toxin.