Microcalorimetric study of <Emphasis Type=”Italic”>Bacillus thuringiensis</Emphasis> growth with different plasmid numbers and various promoters

Summary

A microcalorimetric technique was used to investigate the influence of plasmid copy number and various promoters on the green fluorescent protein expression in <Emphasis Type=”Italic”>Bacillus thuringiensis.</Emphasis> The power-time curves of the growth metabolism of <Emphasis Type=”Italic”>B. thuringiensis</Emphasis> have been determined by using an LKB-2277 bioactivity monitor at 28&deg;C. For evaluation of the results, the maximum peak-heat output power (<Emphasis Type=”Italic”>P</Emphasis><Subscript>max</Subscript>), the generation time (<Emphasis Type=”Italic”>t</Emphasis><Subscript>G</Subscript>), the growth rate constants (<Emphasis Type=”Italic”>k</Emphasis>) in the log phase, the total heat effect (<Emphasis Type=”Italic”>Q</Emphasis><Subscript>total</Subscript>) for the growth metabolism of <Emphasis Type=”Italic”>Bacillus thuringiensis</Emphasis> were determined. The results firstly indicated that the more plasmid copy number per cell the more protein synthesization, and <Emphasis Type=”Italic”>promoter BtI-BtII</Emphasis> had a stronger impact on the gene expression than promoter 3A investigated by the method of microcalorimetry.