Buchnik D, Woldringh C L, Zaritsky A
Department of Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Ann Inst Pasteur Microbiol. 1987 Sep-Oct;138(5):537-47. doi: 10.1016/0769-2609(87)90039-1.
The transition from rod-shaped to spheroidal cells was studied in a temperature-sensitive strain (SP45) of Escherichia coli K12, carrying a mutation (pbpA) in the gene coding for penicillin-binding protein 2 (PBP-2). This transition imposed by the restrictive temperature was associated with reduction of peptidoglycan/surface area and of cellular osmotic stability. Addition of nalidixic acid (20 micrograms/ml) at the temperature shift from 30 to 42 degrees C resulted in lysis of some cells and appearance of spheroidal bulges along the cylinders in other cells, consistent with the hypothesis of envelope weakening due to inactivation of PBP-2.
