FORMATION OF A MICRONUCLEI-LIKE STRUCTURE INDUCED BY COLCHICINE TREATMENT IN SACCHAROMYCES-CEREVISIAE

Minute nuclei named ''smaller nuclei'' were generated when the cells o f Saccharomyces cerevisiae were treated with colchicine. The formation of ''smaller nuclei'' seemed to be related to nuclear division becaus e those nuclei were only produced under conditions suitable for nuclea r division. The fact that the average DNA content of ''smaller nuclei' ' was almost one tenth of that of the isolated normal diploid nuclei s howed that the ''smaller nuclei'' are not condensed nuclei but aneuplo id nuclei like micronuclei in animal cells. It appeared therefore like ly that a micronuclei-like structure could be produced by colchicine t reatment in S. cerevisiae.