Affiliation:
1. Robert Koch-Institut, D-13 353 Berlin, Germany
Abstract
SUMMARY
The primary goal of this review is to provide a compilation of the complex architectural features of staphylococcal cell walls and of some of their unusual morphogenetic traits including the utilization of murosomes and two different mechanisms of cell separation. Knowledge of these electron microscopic findings may serve as a prerequisite for a better understanding of the sophisticated events which lead to penicillin-induced death. For more than 50 years there have been controversial disputes about the mechanisms by which penicillin kills bacteria. Many hypotheses have tried to explain this fatal event biochemically and mainly via bacteriolysis. However, indications that penicillin-induced death of staphylococci results from overall biochemical defects or from a fatal attack of bacterial cell walls by bacteriolytic murein hydrolases were not been found. Rather, penicillin, claimed to trigger the activity of murein hydrolases, impaired autolytic wall enzymes of staphylococci. Electron microscopic investigations have meanwhile shown that penicillin-mediated induction of seemingly minute cross wall mistakes is the very reason for this killing. Such “morphogenetic death” taking place at predictable cross wall sites and at a predictable time is based on the initiation of normal cell separations in those staphylococci in which the completion of cross walls had been prevented by local penicillin-mediated impairment of the distribution of newly synthesized peptidoglycan; this death occurs because the high internal pressure of the protoplast abruptly kills such cells via ejection of some cytoplasm during attempted cell separation. An analogous fatal onset of cell partition is considered to take place without involvement of a detectable quantity of autolytic wall enzymes (“mechanical cell separation”). The most prominent feature of penicillin, the disintegration of bacterial cells via bacteriolysis, is shown to represent only a postmortem process resulting from shrinkage of dead cells and perturbation of the cytoplasmic membrane. Several schematic drawings have been included in this review to facilitate an understanding of the complex morphogenetic events.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology,Infectious Diseases
Reference146 articles.
1. Abraham
E. P.
From penicillins to cephalosporins
50 years of penicillin application—history and trends.
Kleinkauf
H.
von Döhren
H.
1993
7
23
Technische Universität Berlin
Berlin Germany
2. Further observations on penicillin;Abraham E. P.;Lancet,1941
3. Scanning electron microscopy of Staphylococcus;Amako K.;J. Ultrastruct. Res.,1977
4. Concentric circular structure of the cell wall of Staphylococcus epidermidis revealed by scanning electron microscope;Amako K.;J. Electron Microsc.,1978
5. Bacteriophage SP50 as a marker for cell wall growth in Bacillus subtilis
Cited by
244 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献