The proteomic advantage: label-free quantification of proteins expressed in bovine milk during experimentally induced coliform mastitis.

Coliform mastitis remains a primary focus of dairy cattle disease research due in part to the lack of efficacious treatment options for the deleterious side effects of exposure to LPS, including profound intra-mammary inflammation. To facilitate new veterinary drug approvals, reliable biomarkers are needed to evaluate the efficacy of adjunctive therapies for the treatment of inflammation associated with coliform mastitis. Most attempts to characterize the host response to LPS, however, have been accomplished using ELISAs.

Proteomic analysis of the temporal expression of bovine milk proteins during coliform mastitis and label-free relative quantification.

The discovery of biomarkers in milk indicative of local inflammation or disease in the bovine mammary gland has been hindered by the extreme biological complexity of milk, the dynamic range of proteins in the matrix that renders the identification of low-abundance proteins difficult, and the challenges associated with quantifying changes during disease in the abundance of proteins for which no antibody exists. The objectives of the current study were to characterize the temporal expression of milk proteins following Escherichia coli challenge and to evaluate change in relative abundance of identified proteins using a liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) label-free semiquantitative approach. Liquid chromatography-MS/MS conducted on whey from milk samples collected just before infusion with E.

Extension of microwave-accelerated residue-specific acid cleavage to proteins with carbohydrate side chains and disulfide linkages.

This laboratory has introduced a chemical method for residue-specific protein cleavage and has provided a preliminary assessment of the suitability of microwave accelerated acid cleavage as a proteomic tool. This report is a continuing assessment of the fate of common protein modifications in microwave-accelerated acid cleavage. We have examined the cleavage of ribonuclease A and the related N-linked glycoprotein ribonuclease B, and the O-linked glycoprotein alpha crystallin A chain, using MALDI-TOF and LC-ESI-MS to identify the peptide products.

Primary sequence and site-selective hydroxylation of prolines in isoforms of a major peanut allergen protein Ara h 2.

The Ara h 2 proteins are major determinants of peanut allergens. These proteins have not been fully studied at the molecular level. It has been previously proposed that there are two isoforms of Ara h 2, based on primary structures that were deduced from two reported cDNA sequences.

Proteomic analysis of differentially expressed proteins in bovine milk during experimentally induced Escherichia coli mastitis.

The objectives of the current study were to profile changes in protein composition using 2-dimensional gel electrophoresis on whey samples from a group of 8 cows before and 18 h after infection with Escherichia coli and to identify differentially expressed milk proteins by peptide sequencing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry post source decay. Only proteins present in whey fractions of all 8 cows were sequenced to avoid reporting a protein response unique to only a subset of infected cows. Despite the overwhelming presence of casein and beta-lactoglobulin, the low abundance proteins transthyretin, lactadherin, beta-2-microglobulin precursor, alpha-1-acid glycoprotein, and complement C3 precursor could be identified in whey samples from healthy cows.