One Individual Really Could Make a DifferenceLaura Norton 4100741
As antibiotic resistance is a growing problem, the means by which bacteria produce resistance need to be thoroughly understood in order to combat it. The SOS response is known to be responsible for generating adaptive mutations and resistance in bacteria, which is why understanding this mechanism could be the key to reducing or eliminating antibiotic resistance.
Whole populations of Escherichia coli’s SOS Response have been examined, but Friedman et al. (2005) have shown that the individual cell’s response is quite different to the response of the population. They studied the SOS genes by the use of a green fluorescent protein as a reporter for the promoter activity of the response after activation by ultraviolet irradiation. They found that in individual cells, the SOS response exhibits very structured and discrete activation peaks which have precise timing. The peaks correlate with the cell’s growth rate, but not with the stage in the cell cycle. They found that the number of peaks increases with UV dose, their timing is constant and their amplitude reaches saturation.
This study shows the importance of looking at individual cells to see exactly what is happening in the response, as a nonhomologous population can mask individual effects.
http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pbio.0030238
Reference
Friedman, N, Alon, U, Ronen, M, Stavans, J and Vardi, A 2005, ‘Precise temporal modulation in the response of the SOS DNA repair network in individual bacteria’, PLoS Biology, vol. 3, no. 7, pp. 1261 – 1268.
