Formation of protoplasts from Streptococcus faecalis by lysozyme.

Area of Science:

• Microbiology
• Cell Biology

Background:

• Streptococcus faecalis possesses a complex cell wall structure.
• Understanding cell wall composition is crucial for bacterial physiology.

Purpose of the Study:

• To investigate the effect of lysozyme on Streptococcus faecalis cell walls.
• To characterize the resulting protoplasts and their membranes.

Main Methods:

• Incubation of whole cells with crystalline egg-white lysozyme and sucrose.
• Methyl pentose determination of cell walls and protoplast membranes.
• Centrifugation and microscopy (phase-contrast and electron) for structural analysis.

Main Results:

• Lysozyme treatment yielded discrete, osmotically fragile spherical structures (protoplasts).
• Cell walls contained rhamnose, which was absent in protoplast membranes.
• Lysozyme rendered cell walls soluble, with 96% of rhamnose not sedimenting after treatment.

Conclusions:

• Lysozyme effectively removes the cell wall from the studied group D Streptococcus strain.
• Protoplast membranes are devoid of the characteristic cell wall polysaccharide rhamnose.
• This enzymatic degradation provides insight into bacterial cell wall structure and lysis.