DNA polymorphisms and subpopulations in Babesia bovis

Area of Science:

• Molecular Biology
• Parasitology
• Veterinary Science

Background:

• Babesia bovis isolates exhibit limited polypeptide differences, with some potentially acting as host protective antigens.
• Avirulent Babesia bovis strains differ from virulent ones by only a few polypeptides.

Purpose of the Study:

• To identify genes encoding polypeptides that distinguish between Babesia bovis isolates and virulence states.
• To develop molecular tools for differentiating Babesia bovis strains.

Main Methods:

• Construction of a cDNA library from the K-avirulent isolate (KA) poly(A)+ RNA.
• Screening of cDNA clones using colony hybridization with probes from avirulent and virulent isolates.
• Analysis of gene expression patterns and genomic DNA using Southern blotting.

Main Results:

• Identified three cDNA clones (pK4, pK5, pK6) with distinct expression patterns across isolates.
• Clone pK5 specifically hybridized to RNA predominantly expressed in avirulent parasites.
• Southern blot analysis revealed isolate heterogeneity and suggested subpopulation selection during tick passage.

Conclusions:

• Specific genes are differentially expressed between Babesia bovis isolates and virulence states.
• Molecular markers can distinguish between Babesia bovis strains, aiding in epidemiological studies.
• Tick passage can select for specific Babesia bovis subpopulations, influencing parasite characteristics.