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Sodium dodecyl sulfate-sensitive septation in a mitomycin C-sensitive, mtc, mutant of Escherichia coli
Abstract:
A mitomycin C-sensitive, mtc, mutant of Escherichia coli has an altered cell surface and is sensitive to sodium dodecyl sulfate (SDS). The mutant, M27, formed multinucleate nonseptated filaments in the presence of a low concentration of SDS (50 microgram/ml). When the culture grown at that concentration of SDS was diluted with an SDS-free medium, the filaments began to divide at a very rapid rate after a lag of about 20 min. Chloramphenicol inhibited this recovery division when added within 10 min after SDS dilution but did not inhibit the division when added 20 min after dilution. Penicillin G at a low concentration, which is enough to cause filamentation, had virtually no effect on the recovery division of SDS-induced filaments. The division of penicillin G-induced filaments was inhibited by SDS.
Insights
A mitomycin C-sensitive Escherichia coli mutant (M27) exhibits altered cell surface properties, becoming sensitive to sodium dodecyl sulfate (SDS). SDS induces filamentation, but recovery division occurs upon SDS removal, influenced by chloramphenicol timing.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Escherichia coli mutants can exhibit altered cell surface properties affecting growth and division.
- Sodium dodecyl sulfate (SDS) is an anionic surfactant known to impact bacterial cell membranes.
Purpose of the Study:
- To investigate the cell surface alterations and SDS sensitivity in a mitomycin C-sensitive Escherichia coli mutant (M27).
- To characterize the filamentation and recovery division responses of the M27 mutant to SDS exposure and removal.
Main Methods:
- Culturing the M27 mutant in the presence of low-concentration SDS (50 µg/ml) to induce filamentation.
- Diluting SDS-treated cultures into SDS-free medium to observe recovery division.
- Assessing the effect of chloramphenicol and penicillin G on SDS-induced filamentation and recovery division.
Main Results:
- The M27 mutant formed multinucleate, nonseptated filaments in low SDS concentrations.
- Rapid recovery division occurred after SDS dilution, with a lag phase of approximately 20 minutes.
- Chloramphenicol inhibited recovery division if added within 10 minutes of SDS dilution, but not after 20 minutes.
- Low-concentration penicillin G did not affect SDS-induced filament recovery division, while SDS inhibited penicillin G-induced filament division.
Conclusions:
- The M27 mutant's altered cell surface renders it sensitive to SDS, leading to filamentation.
- Recovery from SDS-induced filamentation is a time-dependent process sensitive to protein synthesis inhibition.
- Differential sensitivity of SDS-induced and penicillin G-induced filaments to SDS and recovery conditions suggests distinct underlying mechanisms.