Induction of autolysis in Streptococcus faecium

Area of Science:

• Microbiology
• Bacterial Autolysis

Background:

• Autolysis is a critical process in bacterial cell death and remodeling.
• Understanding the triggers and mechanisms of bacterial autolysis is essential for controlling microbial populations.

Purpose of the Study:

• To investigate the induction of autolysis in Streptococcus faecium using physical and chemical methods.
• To identify the role of endogenous bacterial autolysins in this process.

Main Methods:

• Exponential-phase Streptococcus faecium cells were pretreated by freezing-thawing in Tris buffer.
• Incubation at 37 degrees C in Tris buffer was performed to induce autolysis.
• Autolysis was assessed in the presence of autolysin inhibitors and in autolytic-defective mutants.
• Cell damage and leakage of intracellular components (K+, UV-absorbing substances) were measured.

Main Results:

• Freezing-thawing in Tris buffer effectively promoted autolysis in S. faecium, dependent on Tris concentration.
• Pretreatment caused ultrastructural damage, K+ loss, and leakage of UV-absorbing components.
• Autolysis was inhibited by N-bromosuccinimide and by prior growth in chloramphenicol or tetracycline.
• Autolytic-defective mutants did not lyse, confirming the role of endogenous autolysin.
• Imidazole could also induce autolysis, though to a lesser extent than Tris.

Conclusions:

• The lysis of S. faecium induced by freezing-thawing in Tris buffer is mediated by endogenous bacterial autolysin activity.
• Tris buffer acts as an inducer and potentially an activator for bacterial autolysis.
• This study provides insights into the regulation and induction of bacterial autolysis.