Abstract: By using microcalorimetry method,we have studied ura-auxotrophic mutant of saccharomyces cerevisiae AY,and 3 strains transformed from saccharomyces cerevisiae AY by plasmids.Inoculated in basic medium,ura-auxotrophic mutant of saccharomyces cerevisiae AY shows no heat effect,which means that it can not grow; but it grows in peptone-gluocose medium,and grows vigorously in YPD medium.Adding ura to the basic medium,ura-auxotrophic mutant of saccharomyces cerevisiae AY is then able to grow,and the constant of specific growth rate increases as more ura is added.All of the 3 transformed strains grow in the basic medium,but the thermogenic gragh differs because the plasmids differ in their structure and function.The result shows the difference of genetic characteristics among the target strains.

Key words: Saccharomyces cerevisiae AY, Plasmid, Archaeobacteria promoter, 　Microcalorimetry, Thermokinetics