On the physiological functions of teichoic acids

Area of Science:

• Microbiology
• Cell Biology
• Biochemistry

Background:

• Pneumococcal teichoic acids, typically containing choline, can be biosynthetically altered.
• Replacing choline with analogs like ethanolamine (EA) causes pleiomorphic changes in cell physiology, including resistance to lysis and inhibited cell separation.

Purpose of the Study:

• To investigate the physiological mechanisms behind detergent resistance and inhibited cell separation in pneumococci with modified teichoic acids.
• To elucidate the role of choline and autolysin in pneumococcal cell wall integrity and division.

Main Methods:

• Pneumococci were grown on various amino alcohols to modify teichoic acid composition.
• Physiological studies were conducted to assess cell wall composition, autolysin activity, lysis sensitivity, and cell morphology.
• Kinetics of lysis sensitivity and autolysin reappearance were monitored upon reintroduction of choline.

Main Results:

• Pneumococcal cell walls grown on amino alcohols maintained consistent amino sugar and amino acid composition.
• Both choline- and EA-containing teichoic acids segregated conservatively during cell growth and division.
• Lysis sensitivity in pneumococci was linked to the co-localization of lysis-sensitive cell walls and autolysin at the growth zone.
• Reintroducing choline to EA-grown cells restored lysis sensitivity and active autolysin with specific kinetics.
• Ethanolamine-grown pneumococcal chains exhibited normal cross walls and fully compartmentalized cells.

Conclusions:

• The presence of choline in pneumococcal teichoic acids is crucial for susceptibility to detergent-induced lysis.
• Autolysin activity and its localization are key factors in pneumococcal cell wall integrity and division.
• Biosynthetic modification of teichoic acids provides a tool to study fundamental bacterial cell wall biology.