Effect Of Fluorine On Expression Of GFP Gene And Protein In E.coli

Objective:To study the effect of NaF on expression of GFP mRNA and protein in E.coli.Method:The BL21with GFP plasmid obtained as subject investigation were divided randomly into five groups, such as the control group and four experimental groups (100mmol/L,10mmol/L, lmmol/L,0.1mmol/L). All groups were shaked culture after the gradient treatment with NaF for some time. The growth of E.coli was observed by calculate viable count, the fluorescence intensity values of GFP protein were determined by Fluorospectrophotometry. After the gradient treatment with NaF for6h, extracting RNA, the expression levels of GFP gene were quantified by the real-time RT-PCR. After the gradient treatment with NaF for6h, extracting Protein, the expression levels of GFP protein were determined by SDS-PAGE analysis techniques.Results:1. The BL21with GFP plasmid were induced for different time under different levels Fluoride, the result showed that:Within four hours and eight hours, compared with the control group, high doses of NaF (100mmol/L) was obviously inhibited growth rate of E.coli (p<0.05). However, low doses of NaF (0.1mmol/L, lmmol/L) was a certain accelerated growth of E.coli (p<0.05).2. After treated with fluoride for6h, the Fluorescence values of GFP in E.coli were determined by970CRT Fluorospectrophotometer. Under the same bacterial quantities, Fluorescence value of the blank group was not collected, the result showed that, there were no GFP plasmids in blank group. The fluorescence signal strength was declined in high doses of fluoride (100mmol/L,10mmol/L) compared with the control group, the level fluorescence value was down24.17%and11.90%respectively (p<0.01). However, the fluorescence signal strength was increased in low doses of fluoride (1mmol/L,0.1mmol/L) compared with the control group, was up21.04%and2.51%respectively (p<0.01), especially the fluorescence value of1mmol/L was increased significantly compared with the control group (p<0.01).3. After treated with fluoride for6h, the expression levels of GFP gene mRNA were decreased in high doses of fluoride (100mmol/L,10mmol/L) compared with the control group, the gene expression levels of100mmol/L group and10mmol/L group were down88.97%and66.09%respectively (p<0.01). the gene expression levels of low doses of NaF were increased compared with the control group, the gene expression levels were up7.59%and30.47%respectively, while the group of lmmol/L was increased significantly (p<0.01). 4. After treated with fluoride for6h, the expression levels of GFP protein was significant declined in high doses of fluoride (100mmol/L,10mmol/L) compared with the control group, the protein expression levels of100mmol/L group and10mmol/L group were down75.65%and10.39%, respectively (p<0.01). However, the protein expression levels of GFP were increased in low doses of fluoride (lmmol/L,0.1mmol/L) compared with the control group, the protein expression levels of1mmol/L group and0.1mmol/L group were up15.06%and14.77%, respectively (p<0.01).Conclusion:Within a certain time, the gene mRNA expression and protein expression of GFP were accelerated in low doses of fluoride, the gene mRNA expression and protein expression of GFP were inhibited in high doses of fluoride. The result showed that, transcription of gene and translation of protein were affected by fluoride in E.coli.