The effect of starvation stress on the porin protein expression of Escherichia coli in lake water.

AIMS

The aim was to identify changes in outer membrane proteins (omps), OmpA, OmpC and OmpF, in Escherichia coli under starvation conditions in lake water microcosms studied at different temperatures.

METHODS AND RESULTS

Escherichia coli was incubated in lake water microcosms at a variety of temperatures and the omps studied using quantitative densitometric analysis of protein bands of sodium dodecyl sulphate gels of omp preparations. The amount of OmpF increased over the incubation period relative to that of OmpC whereas the relative abundance of OmpA declined, most notably at 25 and 37 degrees C. This change was linked to changes in peak cell volume as determined by cell measurements.

CONCLUSIONS

Major changes to the omps of E. coli accompany the adaptation of the organism to starvation conditions in lake water microcosms.

SIGNIFICANCE AND IMPACT OF THE STUDY

Prolonged starvation affects the relative amounts of outer membrane porins. This study furthers the understanding of the role played by changes in the omp composition in E. coli during survival in lake water environments.