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Purification & characterisation of haemolysin from Serratia marcescens B-91
R P Tiwari1, J Singh, J S Grewal
1Department of Microbiology, Panjab University, Chandigarh.
Background & Objectives:
Serratia marcescens an opportunistic human pathogen, is frequently encountered in a variety of debilitating diseases. Relatively little is known about its virulence traits though most clinical isolates secrete a distinct haemolysin which is considered as a useful marker for pathogenicity of Serratia. In this study purification and characterisation of S. marcescens B-91 haemolysin have been attempted.
Methods:
S. marcescens B-91 haemolysin was purified to homogeneity from the growth medium using ammonium sulphate fractional precipitation and gel filtration through Sephadex G-75 column. Homogeneity was determined by gel electrophoresis and purified haemolysin was tested for its stability and other characteristics.
Results:
The haemolysin was characterised to be a 45 kDa molecular weight protein on SDS-polyacrylamide gel electrophoresis. It was inactivated at 60-100 degrees C within 30 min, and on overnight treatment with 2 per cent formaldehyde. It was also susceptible to the action of pronase, protease and trypsin.
Interpretation & Conclusions:
The results indicate that the fragile stability of S. marcescens haemolysin is dependent on the storage temperature. The purified haemolysin can be used for understanding the role of haemolysin in the pathogenesis of S. marcescens and also for evaluation of immunoprophylactic activity.
Insights
This study purified and characterized Serratia marcescens haemolysin, a key virulence factor. The purified haemolysin showed fragile stability, offering insights into its role in pathogenicity and potential for immunoprophylaxis.
Area of Science:
- Microbiology
- Biochemistry
Background:
- Serratia marcescens is an opportunistic pathogen linked to various diseases.
- Haemolysin secretion is a common virulence trait in clinical S. marcescens isolates and a marker for pathogenicity.
Purpose of the Study:
- To purify and characterize the haemolysin produced by S. marcescens B-91.
- To investigate the haemolysin's stability and biochemical properties.
Main Methods:
- Purification of S. marcescens B-91 haemolysin using ammonium sulphate precipitation and Sephadex G-75 gel filtration.
- Assessment of homogeneity via gel electrophoresis.
- Characterization of haemolysin stability and properties.
Main Results:
- The purified haemolysin has a molecular weight of 45 kDa.
- It is inactivated by heat (60-100°C), formaldehyde, and proteolytic enzymes (pronase, protease, trypsin).
- Haemolysin stability is temperature-dependent.
Conclusions:
- S. marcescens haemolysin exhibits fragile stability influenced by storage temperature.
- The purified haemolysin is valuable for studying S. marcescens pathogenesis and evaluating immunoprophylactic strategies.
