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Genetic analysis of Streptococcus uberis plasminogen activators
1Institute for Animal Health, Compton Laboratory, Compton, Berkshire, RG20 7NN, UK. phil.ward@bbsrc.ac.uk
The Indian Journal of Medical Research
|July 3, 2004
Summary
Plasminogen activators like PauA are widespread in Streptococcus uberis, a cause of bovine mastitis. This study confirms PauA
Area of Science:
- Bacteriology
- Microbial Pathogenesis
- Molecular Biology
Background:
- Streptococci secrete plasminogen activators that convert host plasminogen to plasmin, aiding pathogenesis.
- PauA was the first identified plasminogen activator from Streptococcus uberis, a bovine mastitis pathogen.
- A second activator, PauB, was found in S. uberis, occupying the same genetic locus as pauA.
Purpose of the Study:
- To investigate the distribution, chromosomal location, and sequence variation of plasminogen activators PauA and PauB in mastitis-associated streptococci.
- To assess the prevalence of these putative virulence factors in various isolates.
Main Methods:
- Southern analysis was used to examine a diverse panel of streptococci and other bovine mastitis-associated bacteria.
- Nucleotide sequence analysis was performed on amplified pauA alleles to assess protein-level sequence variation.
Main Results:
- Plasminogen activators were universally distributed among Streptococcus uberis strains.
- A pauA allele was found in nearly all S. uberis strains; one strain possessed a pauB allele instead at the same locus.
- PauA exhibited very low sequence variation, with changes concentrated in specific residues.
Conclusions:
- The high prevalence of PauA in S. uberis field isolates suggests it provides a significant advantage for bacterial colonization and growth.
- PauA plays a critical role in the pathogenesis of Streptococcus uberis infections.