HOW DO ARCHAEA CO-ORDINATE THE EVENTS OF CELL DIVISION?

Mutations that block essential processes such as cell division must, of necessity, be conditional, i.e., effective under certain conditions but not others. A number of temperature-sensitive mutants of S. acidocaldarius were isolated in 1992 with the help of UCLA undergraduate Ellie Medigholi. Later screening of this collection by collaborator Rolf Bernander at Uppsala University identified several mutants that showed defects in cell division when shifted from the permissive to the restrictive temperature (70º to 81º). The panels below show two mutants which stopped dividing but continued to grow after the shift. In one of these (DG132, left), chromosome replication stopped and the normal nucleoid configuration was lost. In the other (DG134, right), chromosome replication and nucleoid configuration were maintained, resulting in cells with multiple nucleoids [publication 11].  [more Sulfolobus research]