Can Synchronous Cultures of Bacteria Be Manufactured?

Abstract

The bacterial cell cycle is simpler and different than that of the typical eukaryotic cell cycle. The selective pressure during evolution has been directed to achieve optimal growth of the individual free-living microbial cell instead of a variety of replication rates of the differentiated cell within an entire multicellular organism. This means that for most bacterial cells division depends more critically on their success in acquiring and using resources than is the case for most eukaryotic cells. The further implication is that bacterial cells somehow measure their own success in growth and from this ‘decide’ when they should attempt cell cycle events such as cell division and chromosome replication. On the assumption that bacterial division is responsive, directly or indirectly, to cell size, the cell cycle is analyzed here through Monte Carlo simulations.

The results are used to consider the possibility of generating bacterial cultures growing synchronous. Because the precision of the size-at-division is surprisingly good, it appears that some organisms, at least, have a sensory mechanism that responds to their success in cell growth. It is known that the division size of some strains, however, is more precisely regulated than in others. Also, some strains are more precise in dividing the mother's cell cytoplasm to give the same sized daughters. Because some strains are much more precise than others, the possibility is raised that useful synchrony could be obtained with selected strains that are precise in these two aspects. These cultures would useful in studying other aspect of the physiology of cell growth.

KEY WORDS::

• sensing growth
• division in response to growth
• CV of the size-at-division
• equal sizes of daughter cells
• Monte Carlo simulations
• synchronous cultures