Peptidoglycan Synthesis in Salmonella Typhimurium
The rate and topography of peptidoglycan synthesis during the division cycle of Salmonella typhimurium strain 2616 was determined by comparing incorporation of diaminopimelic acid (DAP) into peptidoglycan to incorporation of radioactive amino acids into protein (Cooper, 1988). The observed ratio of DAP incorporation to amino acid incorporation during the division cycle led to the development of a consistent description of peptidoglycan synthesis. It was proposed that (1) the cytoplasm increases exponentially during the division cycle; (2) the surface of the gram-negative cell grows in response to the increase in cytoplasm; (3) the surface grows in such a way as to produce an exponential increase in cell volume; (4) the exponential increase in cell volume accounts for constant cell density during the division cycle; and (5) the synthesis of peptidoglycan is smoothly partitioned between the poles and the cylindrical side walls, allowing exponential increase in cell volume. Similar experimental results were found with Escherichia coli (Cooper and Hsieh, 1988) suggesting that the rate and topography of peptidoglycan synthesis is similar in all rod-shaped, gram-negative bacteria.
KeywordsSingle Strand Cell Wall Synthesis Diaminopimelic Acid Amino Acid Incorporation Peptidoglycan Synthesis
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