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Properties of "diplophage": a lipid-containing bacteriophage
Abstract:
We describe the purification and properties of Dp-1, a bacteriophage isolated from Diplococcus pneumoniae. The phage was sensitive to the organic solvents deoxycholate and Sarkosyl, and its infectivity was reduced by treatment with phospholipase C. Electron microscopy indicated the presence of a double-layered coat around the phage particles. Purified phage preparations contained lipid amounting to about 8.5% of the dry weight of the phage, and thin-layer chromatography resolved the lipids into four components. The phage had a buoyant density in CsCl of 1.47 g/cm3, and a sedimentation constant in 0.1 M NaCl of 313S. Analysis in acrylamide gel electrophoresis indicated the presence of three major proteins. Dp-1 DNA shows a density of 1.681 g/cm3. Neutralizing antisera against the phage have a low potency (K less than 120/min).
Insights
Researchers purified and characterized Dp-1, a bacteriophage from Diplococcus pneumoniae. This study details its structural, chemical, and physical properties, including lipid and protein composition and DNA characteristics.
Area of Science:
- Microbiology
- Virology
- Biochemistry
Background:
- Bacteriophages are viruses that infect bacteria and play crucial roles in microbial ecosystems.
- Understanding phage structure and properties is essential for applications in biotechnology and medicine.
Purpose of the Study:
- To purify and characterize the bacteriophage Dp-1 isolated from Diplococcus pneumoniae.
- To elucidate the physical, chemical, and structural properties of Dp-1.
Main Methods:
- Bacteriophage isolation and purification techniques.
- Sensitivity assays using organic solvents and enzymes (phospholipase C).
- Electron microscopy for structural analysis.
- Biophysical characterization including buoyant density and sedimentation analysis.
- Biochemical analysis of lipid and protein composition using chromatography and electrophoresis.
- DNA density determination.
Main Results:
- Dp-1 is sensitive to deoxycholate, Sarkosyl, and phospholipase C, indicating a lipid-containing structure.
- Electron microscopy revealed a double-layered coat.
- Lipids constitute approximately 8.5% of the dry weight, resolved into four components.
- Analysis identified three major proteins and determined DNA density.
- Buoyant density in CsCl was 1.47 g/cm³, and sedimentation constant was 313S.
Conclusions:
- Dp-1 possesses a complex structure with a lipid envelope and protein components.
- The characterized properties provide a foundation for further research into Dp-1's biology and potential applications.