Identification of free oligosaccharides in human and animal milk:principle study by bovine mammary epithelial cells

Free oligosaccharides are generated from lipid-linked oligosaccharides by a pyrophosphatase activity and oligosaccharyltransferase and from misfolded glycoproteins by peptide: N-glycanase in both the ER and cytoplasm. Oligosaccharides are constituted by 3-10 monosaccharide units formed with 5 basic monosaccharides: L-fucose, D-glucose, D-galactose, N-acetyl-D-glucosamine and N-acetyl-D-neuraminic acid. Glycosylation is the important post-transport modification for proteins and play important roles in the structure and functions of proteins. Protein glycosylation have been widely investigated in medical field and illness related fields. Formation of glycosylation on proteins result in corresponding changes in proteins’ structure and functions. Numerous studies mentioned that the glycan chains in glycoproteins and free oligosaccharides are considered involved in many biological functions such as immune, signalling and cell-cell recognition. Breastfeeding takes the short and long terms for growth and development of infants. However, the bovine milk based infant formulas play a key role when the human milk is not enough or breastfeeding is not possible. The differences in constitutions between human milk and bovine milk might lead to defects in infant’s development. The aim of this project is to first explore the different constitutions between human and bovine milk in conjunction glycoproteins and oligosaccharides, thus further investigate and regulated the milk synthesis in vitro situation. It provides a systematic approach for elucidating the effects of hormones and sugars supplement on formation of oligosaccharides. Bovine mammary epithelial cells belong to bovine mammary gland tissue and should have the ability to secrete the milk components during the lactation. Here, we first verify the feasibility of the bovine mammary epithelial cells working as cell model to investigate the milk synthesis in cell vitro situation and investigate the pathways for the sugars and amino acids in the cells in order to better understand the milk synthesis in BMECs. It can be benefits to regulate milk synthesis in cows which aim to improve the quality and nutrients value of milk.