title: Keratin and S100 calcium-binding proteins are major constituents of the bovine teat canal lining.
abstract: The bovine teat canal provides the first-line of defence against pathogenic bacteria infecting the mammary gland, yet the protein composition and host-defence functionality of the teat canal lining (TCL) are not well characterised. In this study, TCL collected from six healthy lactating dairy cows was subjected to two-dimensional electrophoresis (2-DE) and mass spectrometry. The abundance and location of selected identified proteins were determined by western blotting and fluorescence immunohistochemistry. The variability of abundance among individual cows was also investigated. Two dominant clusters of proteins were detected in the TCL, comprising members of the keratin and S100 families of proteins. The S100 proteins were localised to the teat canal keratinocytes and were particularly predominant in the cornified outermost layer of the teat canal epithelium. Significant between-animal variation in the abundance of the S100 proteins in the TCL was demonstrated. Four of the six identified S100 proteins have been reported to have antimicrobial activity, suggesting that the TCL has additional functionality beyond being a physical barrier to invading microorganisms. These findings provide new insights into understanding host-defence of the teat canal and resistance of cows to mastitis.
authors.affiliation: Dairy Foods, AgResearch Ltd, Ruakura Research Centre, Hamilton, 3240, New Zealand. grant.smolenski@agresearch.co.nz.|University of Waikato, Hamilton, 3240, New Zealand. grant.smolenski@agresearch.co.nz.
authors.forename: Grant A
authors.initials: GA
authors.lastname: Smolenski
authors.affiliation: University of Waikato, Hamilton, 3240, New Zealand. rtmc@waikato.ac.nz.
authors.forename: Ray T
authors.initials: RT
authors.lastname: Cursons
authors.affiliation: CSIRO, Agriculture Flagship, Chiswick, Armidale, NSW 2350, Australia. brad.hine@csiro.au.
authors.forename: Brad C
authors.initials: BC
authors.lastname: Hine
authors.affiliation: Dairy Foods, AgResearch Ltd, Ruakura Research Centre, Hamilton, 3240, New Zealand. tom.wheeler@agresearch.co.nz.
authors.forename: Thomas T
authors.initials: TT
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D002417:Cattle / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D007633:Keratins / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D013058:Mass Spectrometry; D020543:Proteome; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D020543:Proteome; D009418:S100 Proteins; D007633:Keratins