Characterization of Prototheca zopfii associated with outbreak of bovine clinical mastitis in herd of Beijing, China.

Prototheca zopfii (P. zopfii) has become an important cause of bovine mastitis in many countries. In the present study, to better understand the occurrence of one clinical mastitis (CM) outbreak due to P. zopfii, the molecular characterization and resistance patterns of the microalga were described. P. zopfii strains were isolated from 17 of 23 quarters, which suffered CM in the outbreak, and 7 of 46 CM recovered quarters before the outbreak, as well as 2 of 75 environmental samples in the dairy farm. All strains were identified as genotype 2 by genotype-specific PCR analysis. Results of in vitro antimicrobial and antifungal susceptibility tests indicated that these strains were resistant to majority of tested drugs, with the only exception of amphotericin B, nystatin, streptomycin, gentamicin, and amikacin. This is the first report about CM outbreak caused by P. zopfii in China. These data suggest that P. zopfii may represent a serious risk in the studied herd, and this microalga could be an important potential pathogen causing mastitis in dairy herds of Beijing.

[Relationships between copy number variations and human disease and its perspective in animal disease-resistant breeding].

Copy number variations (CNVs) refer to the deletion, insertion, and duplication of genes over 1 kb in length. CNVs were widely found in human and other mammalian genomes. Here, we mainly reviewed the impacts of CNVs on the human diseases, and introduced the general detecting methods for CNVs. We also discussed the potential relationship between CNVs and disease-resistant breeding of animals. Because of the significant effects of CNVs on the resistance and susceptibility of disease, CNVs can be used in the marker-assisted selection, QTL fine mapping, and disease-resistant breeding of livestocks by means of biotechnologies.