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Isolation and characterization of a filamentous phage, Vf33, specific for Vibrio parahaemolyticus
Abstract:
Phage Vf33, a filamentous phage about 1,400 nm long and 7 nm wide, specific for Vibrio parahaemolyticus, was isolated and characterized. The buoyant density of Vf33 in CsCl was 1.292 g/cm3. As with other filamentous phages, the lytic activity of Vf33 was resistant to heating below 80 C and to treatment with diethylether, acetone or methanol but sensitive to chloroform. The nucleic acid of this phage is single-stranded circular DNA 8.4 kb in size. The viral genome was converted to a double-stranded replicative form in the host-cell. Among the strains tested, only V. parahaemolyticus strains possessing K38 antigen was sensitive to the phage.
Insights
A novel filamentous phage, Vf33, targeting Vibrio parahaemolyticus was identified. This phage specifically infects strains with the K38 antigen, offering potential for targeted Vibrio parahaemolyticus control.
Area of Science:
- Microbiology
- Virology
- Bacteriology
Background:
- Vibrio parahaemolyticus is a significant foodborne pathogen.
- Filamentous phages are viruses that infect bacteria and have potential applications in therapy and diagnostics.
- Characterization of specific phages is crucial for understanding their biological properties and potential uses.
Purpose of the Study:
- To isolate and characterize a novel filamentous phage, designated Vf33.
- To determine the host specificity and physical and chemical properties of phage Vf33.
- To investigate the nature of the nucleic acid within the phage genome.
Main Methods:
- Isolation and purification of phage Vf33 from infected bacterial cultures.
- Determination of phage morphology (length, width) and buoyant density.
- Assessment of phage lytic activity under various physical (heat) and chemical (solvents) conditions.
- Analysis of phage nucleic acid type (DNA/RNA, single/double-stranded, circular/linear) and size.
- Testing phage sensitivity against different strains of Vibrio parahaemolyticus, including those with specific antigens.
Main Results:
- Phage Vf33 was isolated and characterized as a filamentous phage (1,400 nm long, 7 nm wide) specific for Vibrio parahaemolyticus.
- Its buoyant density was determined to be 1.292 g/cm3 in CsCl.
- Vf33 exhibited resistance to heat (below 80°C) and certain organic solvents (diethylether, acetone, methanol) but was sensitive to chloroform.
- The phage genome consists of single-stranded circular DNA, 8.4 kb in size, which converts to a double-stranded replicative form in the host cell.
- Only Vibrio parahaemolyticus strains possessing the K38 antigen were sensitive to phage Vf33.
Conclusions:
- Phage Vf33 is a newly identified filamentous phage with distinct physical and chemical properties.
- Its host specificity is restricted to Vibrio parahaemolyticus strains carrying the K38 antigen.
- The characterization of Vf33 provides insights into filamentous phage biology and suggests potential for targeted applications against specific Vibrio parahaemolyticus strains.