Coliphage HK243: biological and physicochemical characteristics

Area of Science:

• Microbiology
• Virology
• Bacteriology

Background:

• Coliphage HK243 infects specific strains of Escherichia coli, forming opaque plaques.
• The phage exhibits a virulent life cycle, with no lysogenic survivors detected.

Purpose of the Study:

• To characterize the biological and genetic properties of coliphage HK243.
• To investigate phage-host interactions and potential genetic mapping.

Main Methods:

• One-step growth experiments to determine eclipse and latent periods.
• Plaque assays on different E. coli strains.
• Analysis of phage-infected cell survival and resistance.
• Electron microscopy for virion morphology.
• DNA extraction and base composition analysis.

Main Results:

• HK243 forms 1-2 mm opaque plaques on E. coli C and K-12, clearing with chloroform.
• Eclipse and latent periods are 20 and 30 minutes, respectively.
• Infected cells produce phage for up to 80 minutes; high MOI leads to lysis.
• Maltose-negative, lambda-resistant mutants isolated from survivors.
• Virions have tadpole morphology; genome is linear, duplex DNA (approx. 44x10^6 Da).
• DNA base composition: 33% A, 31% T, 16% G, 20% C.

Conclusions:

• HK243 is a virulent coliphage with defined growth kinetics and morphology.
• Genetic analysis suggests a circular linkage map.
• Phage-host interactions reveal potential for isolating specific bacterial mutants.