title: Peptidomic analysis of healthy and subclinically mastitic bovine milk.
abstract: A variety of proteases release hundreds of endogenous peptide fragments from intact bovine milk proteins. Mass spectrometry-based peptidomics allows for high throughput sequence assignment of a large number of these peptides. Mastitis is known to result in increased protease activity in the mammary gland. Therefore, we hypothesized that subclinically mastitic milks would contain higher concentrations of released peptides. In this work, milks were sampled from three cows and, for each, one healthy and one subclinically mastitic teat were sampled for milk. Peptides were analyzed by nano-liquid chromatography quadrupole time of flight tandem mass spectrometry and identified with database searching. In total, 682 peptides were identified. The total number of released peptides increased 146% from healthy to subclinically mastitic milks (p< 0.05), and the total abundance of released peptides also increased significantly (p< 0.05). Bioinformatic analysis of enzyme cleavage revealed increases in activity of cathepsin D and elastase (p< 0.05) with subclinical mastitis.
authors.affiliation: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Andres
authors.initials: A
authors.lastname: Guerrero
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States ; Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: David C
authors.initials: DC
authors.lastname: Dallas
authors.affiliation: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Contreras
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Aashish
authors.initials: A
authors.lastname: Bhandari
authors.affiliation: Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Angela
authors.initials: A
authors.lastname: Cánovas
authors.affiliation: Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Alma
authors.initials: A
authors.lastname: Islas-Trejo
authors.affiliation: Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Medrano
authors.affiliation: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Evan A
authors.initials: EA
authors.lastname: Parker
authors.affiliation: Dairy Science and Technology Group, Food Quality and Design Group, Wageningen University, Bomenweg 2, Wageningen, 6703 HD, The Netherlands.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.affiliation: Dairy Science and Technology Group, Food Quality and Design Group, Wageningen University, Bomenweg 2, Wageningen, 6703 HD, The Netherlands.
authors.forename: Kasper
authors.initials: K
authors.lastname: Hettinga
authors.affiliation: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Chee
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States ; Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: J Bruce
authors.initials: JB
authors.lastname: German
authors.affiliation: Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States ; Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Daniela
authors.initials: D
authors.lastname: Barile
authors.affiliation: Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
authors.forename: Carlito B
authors.initials: CB
authors.lastname: Lebrilla