Identification of potential protein biomarkers for early detection of pregnancy in cow urine using 2D DIGE and label free quantitation.

BACKGROUND: An early, reliable and noninvasive method of early pregnancy diagnosis is prerequisite for efficient reproductive management in dairy industry. The early detection of pregnancy also help in to reduce the calving interval and rebreeding time which is beneficial for industries as well as farmers. The aim of this work is to identify potential biomarker for pregnancy detection at earlier stages (16-25 days). To achieve this goal we performed DIGE and LFQ for identification of protein which has significant differential expression during pregnancy. RESULTS: DIGE experiment revealed a total of eleven differentially expressed proteins out of which nine were up regulated having fold change ≥1.5 in all time points. The LFQ data analysis revealed 195 differentially expressed proteins (DEPs) out of 28 proteins were up-regulated and 40 down regulated having significant fold change ≥1.5 and ≤0.6 respectively. Bioinformatics analysis of DEPs showed that a majority of proteins were involved in regulation of leukocyte immunity, endopeptidase inhibitor activity, regulation of peptidase activity and polysaccharide binding. CONCLUSION: This is first report on differentially expressed protein during various time points of pregnancy in cow to our best knowledge. In our work, we identified few proteins such MBP, SERPIN, IGF which were differentially expressed and actively involved in various activities related to pregnancy such as embryo implantation, establishment and maintenance of pregnancy. Due to their involvement in these events, these can be considered as biomarker for pregnancy but further validation of is required.

Early pregnancy diagnosis in bovines: current status and future directions.

An early and accurate diagnosis of reproductive dysfunctions or aberrations is crucial to better reproductive management in livestock. High reproductive efficiency is a prerequisite for high life-time production in dairy animals. Early pregnancy diagnosis is key to shorten the calving interval through early identification of open animals and their timely treatment and rebreeding so as to maintain a postpartum barren interval close to 60 days. A buffalo, the most important dairy animal in the Indian subcontinent, is known for problems related to high calving interval, late puberty, and high incidence of anestrus. Lack of reliable cow-side early pregnancy diagnosis methods further aggravates the situation. Several methods of pregnancy diagnosis are being practiced in bovine species, yet none qualifies as the ideal pregnancy diagnosis method due to the inherent limitations of sensitivity, accuracy, specificity, speed, and ease of performing the test. The advancement of molecular techniques like proteomics and their applications in animal research has given a new hope to look for pregnancy biomarker molecules in these animals. This review attempts to examine common pregnancy diagnosis methods available for dairy animals, while assessing the usefulness of the modern technologies in detecting novel pregnancy markers and designing future strategies for research in this area.

Profiling of urinary proteins in Karan Fries cows reveals more than 1550 proteins.

Urine is a non-invasive source of biological fluid, which reflects the physiological status of the mammals. We have profiled the cow urinary proteome and analyzed its functional significance. The urine collected from three healthy cows was concentrated by diafiltration (DF) followed by protein extraction using three methods, namely methanol, acetone, and ammonium sulphate (AS) precipitation and Proteo Spin urine concentration kit (PS). The quality of the protein was assessed by two-dimensional gel electrophoresis (2DE). In-gel digestion method revealed more proteins (1191) in comparison to in-solution digestion method (541). Collectively, 938, 606 and 444 proteins were identified in LC-MS/MS after in-gel and in-solution tryptic digestion of proteins prepared by AS, PS and DF methods, respectively resulting in identification of a total of 1564 proteins. Gene ontology (GO) using Panther7.0 grouped the majority of the proteins into cytoplasmic (location), catalytic activity (function), and metabolism (biological processes), while Cytoscape grouped proteins into complement and coagulation cascades; protease inhibitor activity and wound healing. Functional significance of few selected proteins seems to play important role in their physiology. Comparative analysis with human urine revealed 315 overlapping proteins. This study reports for the first time evidence of more than 1550 proteins in urine of healthy cow donors. This article is part of a Special Issue entitled: Proteomics in India.