[Characterization of haemolysis of the Vibrio parahaemolyticus no.93]

Area of Science:

• Microbiology
• Food Safety
• Bacterial Pathogenesis

Background:

• Vibrio parahaemolyticus is a significant cause of foodborne illness.
• Haemolysin is a key virulence factor in Vibrio parahaemolyticus infections.
• Understanding the specific virulence factors of clinical strains is crucial for public health.

Purpose of the Study:

• To characterize the haemolysin produced by a clinical isolate of Vibrio parahaemolyticus from Taiwan.
• To investigate the enzymatic activities and protein profile of the extracellular haemolytic factor.
• To determine if the haemolysin possesses protease activity against gelatin and hemoglobin.

Main Methods:

• Isolation and characterization of Vibrio parahaemolyticus strain No.93 from Taiwan.
• Hemolytic activity assay on Wagatsuma medium with varying NaCl concentrations.
• DNA hybridization to detect tdh and trh genes.
• Analysis of extracellular protein using SDS-PAGE, gelatin-SDS-PAGE, and hemoglobin-SDS-PAGE.
• Evaluation of heat tolerance and enzyme activities of the crude extracellular protein.

Main Results:

• Vibrio parahaemolyticus No.93 exhibited weak hemolysis on 7% NaCl medium but significant hemolysis on 3% NaCl medium with human blood.
• The strain lacked the tdh and trh genes, commonly associated with virulence.
• The crude extracellular protein was thermolabile and showed protease activity against gelatin and hemoglobin, with distinct bands observed at 62 kDa, 52 kDa, and 41 kDa on zymography gels.
• A 64 kDa protein band was observed on standard SDS-PAGE.

Conclusions:

• The clinical Vibrio parahaemolyticus strain No.93 produces a haemolysin that lacks typical virulence genes (tdh, trh).
• This haemolysin possesses protease activities capable of degrading gelatin and hemoglobin.
• Further research is needed to confirm if these proteases are indeed the virulence factors responsible for the pathogenicity of this strain.