Project description:Analysis of gene expression changes in milk somatic cells (MSCs) that occur with Staph Aureus mastitis. We used in house microarrays to indicate the changes that occur in gene expression in the BMCs as a result of mastitis Keywords: single time point, comparison mastitis animal vs control animal
Project description:Analysis of gene expression changes in blood mononuclear cells (BMCs) that occur with Staph Aureus mastitis. We used in house microarrays to indicate the changes that occur in gene expression in the BMCs as a result of mastitis Keywords: Comparison mastitis animal vs control animal
Project description:Background: S. aureus is one of the main pathogen involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable and ranges from subclinical to gangrenous mastitis. Such variability implies host as well as staphylococcal factors. This work is an in-depth characterization of S. aureus mastitis isolates to identify factors involved in mastitis severity. Methods and findings: We combined three “omic” approaches to comprehensively compare two clonally related S. aureus strains that were isolated from and shown to reproducibly induce severe (strain O11) and milder (strain O46) mastitis in ewes. The genomes of O11 and O46 were sequenced (Illumina technology) to determine their respective gene content and comparative transcriptomic and proteomic analyses were carried out on both strains grown in conditions mimicking mastitis context. High differences were highlighted in mobile genetic elements, iron acquisition and metabolism, transcriptional regulation and exoprotein production. In particular, O11 overproduced exoproteins, including toxins and proteases when compared to O46. This was confirmed in 4 other S. aureus strains isolated from subclinical or clinical mastitis cases. Dose-dependant production of some staphylococcal factors seem to play a role in hypervirulence of strains isolated from severe mastitis. Mobile genetic elements, transcriptional regulators, exoproteins or strain ability to deal with iron starvation constitute good targets for further research to better define the underlying mechanisms of mastitis severity. Conclusions: Differences observed in mastitis severity likely result from the ability of the strains to adapt and to express virulence factors in the mastitis context rather than from deep variations in gene content. Expression of S. aureus O46 from subclinical mastitis and O11 from a lethal gangrenous mastitis were compared at two different times
Project description:Background: S. aureus is one of the main pathogen involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable and ranges from subclinical to gangrenous mastitis. Such variability implies host as well as staphylococcal factors. This work is an in-depth characterization of S. aureus mastitis isolates to identify factors involved in mastitis severity. Methods and findings: We combined three “omic” approaches to comprehensively compare two clonally related S. aureus strains that were isolated from and shown to reproducibly induce severe (strain O11) and milder (strain O46) mastitis in ewes. The genomes of O11 and O46 were sequenced (Illumina technology) to determine their respective gene content and comparative transcriptomic and proteomic analyses were carried out on both strains grown in conditions mimicking mastitis context. High differences were highlighted in mobile genetic elements, iron acquisition and metabolism, transcriptional regulation and exoprotein production. In particular, O11 overproduced exoproteins, including toxins and proteases when compared to O46. This was confirmed in 4 other S. aureus strains isolated from subclinical or clinical mastitis cases. Dose-dependant production of some staphylococcal factors seem to play a role in hypervirulence of strains isolated from severe mastitis. Mobile genetic elements, transcriptional regulators, exoproteins or strain ability to deal with iron starvation constitute good targets for further research to better define the underlying mechanisms of mastitis severity. Conclusions: Differences observed in mastitis severity likely result from the ability of the strains to adapt and to express virulence factors in the mastitis context rather than from deep variations in gene content.
Project description:Mastitis in dairy cattle can result from infection by a range of microorganisms but is principally caused by coliform bacteria and gram positive bacteria such as Staphylococcus aureus (S. aureus). The former species are often acquired by environmental contamination while S. aureus is particularly problematic due to its resistance to antibiotic treatments and ability to reside within mammary tissue in a chronic, subclinical state. The transcriptional and translational responses within bovine mammary epithelial tissue subjected to intramammary challenge with S. aureus are poorly characterised, particularly at the earliest stages of infection. A Bovine Innate Immune Microarray was employed to measure changes in gene expression occurring in bovine mammary tissues sampled from three dairy cows after a brief and graded intramammary challenge with a virulent strain of S. aureus. Keywords: dose response, disease state analysis
Project description:Mastitis in dairy cattle can result from infection by a range of microorganisms but is principally caused by coliform bacteria and gram positive bacteria such as Staphylococcus aureus (S. aureus). The former species are often acquired by environmental contamination while S. aureus is particularly problematic due to its resistance to antibiotic treatments and ability to reside within mammary tissue in a chronic, subclinical state. The transcriptional and translational responses within bovine mammary epithelial tissue subjected to intramammary challenge with S. aureus are poorly characterised, particularly at the earliest stages of infection. A Bovine Innate Immune Microarray was employed to measure changes in gene expression occurring in bovine mammary tissues sampled from three dairy cows after a brief and graded intramammary challenge with a virulent strain of S. aureus. Keywords: dose response, disease state analysis
Project description:Mastitis in dairy cattle can result from infection by a range of microorganisms but is principally caused by coliform bacteria and gram positive bacteria such as Staphylococcus aureus (S. aureus). The former species are often acquired by environmental contamination while S. aureus is particularly problematic due to its resistance to antibiotic treatments and ability to reside within mammary tissue in a chronic, subclinical state. The transcriptional and translational responses within bovine mammary epithelial tissue subjected to intramammary challenge with S. aureus are poorly characterised, particularly at the earliest stages of infection. A Bovine Innate Immune Microarray was employed to measure changes in gene expression occurring in bovine mammary tissues sampled from three dairy cows after a brief and graded intramammary challenge with a virulent strain of S. aureus. Keywords: dose response, disease state analysis
Project description:Purpose: To identify the expression profiling of miRNA in peripheral blood of dairy cows in response to S. aureus-infected mastitis and explore the biomarkers for early diagnosis of S. aureus-infected mastitis. Methods: RNAseq technology was used to determine the expression profiles of microRNA (miRNA) from peripheral blood of Chinese Holstein cows infected with S. aureus at 0, 1, 3, 5, and 7 days. Results: Ttal of 288 differentially expressed miRNAs (DIE-miRNA) including 108 known and 180 novel predicted miRNAs, involved in 10 immune system-related signaling pathways. Compare with the 0 dpi, the number of DIE-miRNAs in 1, 3, 5, and 7 dpi groups were 12, 21, 75, and 48, respectively. It was also found that the expression variation of up-regulated expression of miR-320a, miR-19a, and miR-19b as well as down-regulated expression of miR-143, miR‑205, and miR‑24 reached a significant level on the 5 dpi and 7 dpi. However, at different times after S. aureus infection, miR-1301 was significantly up-regulated in peripheral blood. miR-2284r was significantly down-regulated. Conclusion: miR-1301 and miR-2284r might be the new blood biomarkers for S. aureus-infected dairy cow mastitis. The above results laid a new foundation for the research and development of molecular diagnosis and biological therapy technology for S. aureus-infected mastitis in dairy cow.