A quick and efficient method for interruption of bacterial conjugation

Abstract

Jacob & Wollman (1961) produced interruption of chromosome transfer during conjugation in E. coli K-12 by exposing conjugating pairs to high shear forces created by a propeller-type mixer (a Waring blendor). In our laboratory, efforts to use this method were not completely successful because of the relatively long times required to ‘blend’ each sample and the large variations from sample to sample in the efficiency of separating mating couples (‘blending efficiency’). The variations in blending efficiency were thought to be due to lack of homogeneity of mixing in the blendor chamber. We have obtained much more satisfactory results by using a vibratory mixer which shakes the entire sample chamber and thoroughly agitates all the cells. Furthermore this vibratory blendor is much easier to use and permits taking at least twice as many samples per unit time, as compared to the usual blendor method.