DAVOR MILlClC and MERCEDES WRISCHER

G o l d i n (1963) found in Kazakhstan an interesting strain of tobacco mosaic virus (TMV). B r e a k (1978) established that this Kazakhstan strain (Ka strain) of TMV was defective and that it infected tobacco plants very slowly or the systemic infection was lacking. Its thermal inactivation point lay between 75 and 80° C. In fresh infective sap virus particles of normal length were found very rarely and very long particles of various length were often present. These data were also confirmed by M i 1 i c i c et al. (1979) and M i 1 i c i c and W r i s c h e r (1980) who mostly studied the fine structure of inclusion bodies and the form of virus particles.