Increasing plasmid transformation efficiency of natural spizizen method in Bacillus Subtilis by a cell permeable peptide

Some of bacterial species are able to uptake DNA molecule from environment، the yield of this process depends on some conditions such as plasmid size and host type. In the case of Bacillus subtilis، DNA uptake has low efficacy. Using Spizizen minimal medium is common method in plasmid transformation into B. subtilis، but rate of this process is not suitable and noteworthy. The aim of this study was investigation of novel method for improvement of DNA transformation into B. subtilis based on CM11 cationic peptide as a membrane permeable agent.

In this study، for optimization of pWB980 plasmid transformation into B. subtilis، the CM11 cationic peptide was used. For this purpose، B. subtilis competent cell preparation in the present of different concentration of peptide was implemented by two methods. In the first method، after treatment of bacteria with different amount of peptide for 14h، plasmid was added. In the second method، several concentration of peptide with plasmid was exposed to bacteria simultaneously. Bacteria that uptake DNA were screened on LB agar medium containing kanamycin. The total transformed bacteria per microgram of DNA was calculated and compared with the control.

Plasmid transformation in best conditions was 6. 5 folds higher than the control. This result was statistically significant (P value <0. 001). Discussion and

This study showed that CM11 cationic peptide as a membrane permeable agent was able to increase plasmid transformation rate into B. subtilis. This property was useful for resolution of low transformation efficacy.