[Automatic synchronization of growth of "Escherichia coli" (author's transl)]

Abstract

Growth of bacteria in a fermentor is limited by an essential nutrient here inorganic phosphate. After starvation, the culture is diluted by an automatic device in such a way that the limiting nutrient concentration allows exactly one doubling. After 10 to 16 automatic cycles, which can be achieved overnight, synchronous bacterial cycles can be observed to occur spontaneously in non-limiting culture conditions, i.e. open systems. The operating procedures of the prototype are outlined. This "Automatic Synchronizer" has a capacity of about 0.1 g dry bacterial weight per cycle. Synchrony and homogeneity index are suggested, and applied to concrete examples of synchronous growth in closed and open systems. The maintenance of good synchrony in an open system throughout 6 cell cycles allows one to consider microbial growth and metabolism in a culture as reflecting the time schedule of the individual cell instead of being related to the statistical mean of a random cell population. The contradiction between the generation time variability observed under the microscope for individual clones and the amazing maintenance of good synchrony in our culture, is also discussed.