زهرا رودباری

Background: Mastitis is one of the health disorders with large effect on dairy farms and animal welfare it is caused by infection of pathogenic microorganisms such as Escherichia coli, Streptococcus uberis and Staphylococcus aureus. Alterations in milk composition, reduced milk quality and the production and treatment costs all contribute to the economic impact of this disease. Mastitis causes concern regarding both animal welfare and human health. For the development of effective strategies to control mastitis it is important to gain an in-depth understanding of the molecular mechanisms underlying the host immune response to the infection. Objective: the objective of this study was to identify the biological pathways affected in mastitis that show most gene expression changes in the bovine mammary gland that has an intramammary infection with E.coli using publicly available transcriptomic data. Methods: Transcriptomics data from Sipka et al was used in the present study (GSE50685). They measured gene expression in bovine mammary gland infected with E. coli. They compared gene expression after treatment with the antibiotic cefapirin and prednisolone with untreated bovine mammary gland tissue. Gene expression analysis was performed with the Affymetrix Bovine Genome Array. The data quality was evaluated and data normalization was performed using ArrayAnalysis.org. All arrays passed quality control and were analyzed further. Pathway analysis on differentially regulated genes was performed using PathVisio . Results: The regulation of mastitis is possibly the result of interaction of physiological and immunological processes which affects the bovine mammary tissue, identifying these processes with pathway analysis can help to understand mechanisms of cellular signaling pathways involving in mastitis. Pathway analysis revealed thirty-tree pathways that were signi/cantly different (z-score > 1.96), ten of which were known to be involved in immune system regulation and meta