Occurrence of the bacteriophage lambda receptor in some enterobacteriaceae

Area of Science:

• Microbiology
• Bacteriology
• Virology

Background:

• The lambda receptor, an outer membrane protein in Escherichia coli K-12, plays a role in phage lambda inactivation.
• While lambda receptor activity is widespread in E. coli, many strains do not support phage growth due to in vivo receptor masking or other blocks.
• The maltose regulon influences lambda receptor presence in Shigella, with most Mal+ strains possessing it.

Purpose of the Study:

• To investigate the presence and activity of the lambda receptor in various bacterial strains.
• To understand the relationship between maltose metabolism (Mal+) and lambda receptor expression in Shigella.
• To explore the reasons for phage lambda's failure to grow on certain E. coli and Shigella strains.

Main Methods:

• Analysis of lambda receptor activity in bacterial extracts.
• Testing phage lambda adsorption and plaque formation on different bacterial strains.
• Comparison of receptor presence in Mal+ and Mal- strains of Shigella.

Main Results:

• Lambda receptor activity was detected in most wild-type E. coli strains, but in vivo masking often prevented phage growth.
• Most Mal+ Shigella strains exhibited lambda receptor activity, suggesting regulation by the maltose regulon.
• Phage lambda adsorbed to and formed plaques on some Mal+ Shigella strains, albeit at low frequencies. No receptor activity was found in Salmonella or Levinea.

Conclusions:

• The lambda receptor is a common outer membrane protein in E. coli and Shigella, with its expression linked to the maltose regulon in Shigella.
• In vivo receptor masking is a significant factor limiting phage lambda propagation in E. coli.
• Further investigation is needed to elucidate the mechanisms blocking phage growth when adsorption occurs.