The effects of insulin and glucose on growth and expression of mar regulon in E. coli

Aim:Host factors
are known to modulate virulence, antibiotic susceptibility and growth of
bacteria. In the present study we aimed to investigate the effect of human
insulin and glucose on growth and expression of mar regulon (marA, marR, ompF, acrA, acrB and tolC) of E. coli SPC105. Material and Methods:E. coli SPC105 was
grown in tryptic soy broth (TSB-control) and TSB containing 20 µU/mL insulin,
200 µU/mL insulin, 0.1% glucose and 200 µU/mL insulin + 0.1% glucose. Growths
were determined via turbidimetric method. 
Quantitative polymerase chain reaction (qPCR) was used to determine the
gene expression levels. Statistical analysis were performed via Tukey’s post
hoc-test. Results:According to
absorbance values, it has been shown that 0.1% glucose and 200 µU/mL insulin +
0.1% glucose have led a significant decrease on growth. Expression of acrA gene was shown to be decreased in
the presence of 200μIU insulin. Expressions of marR and marA were also
decreased in 200μU insulin, 0.1 % glucose+200μU insulin and 0.1% glucose added
TSB. Decreasing of marA, marR and acrA expressions were shown to be statistically significant
(p<0.05).

Conclusion:The results
of the present study has shown once more that host factors may influence the
growth of a bacterium as well as gene expressions associated with antibiotic
susceptibilities.