Annotation and structural elucidation of bovine milk oligosaccharides and determination of novel fucosylated structures

Abstract

Bovine milk oligosaccharides (BMOs) are recognized by the dairy and food industries, as well as by infant formula manufacturers, as novel, high-potential bioactive food ingredients. Recent studies revealed that bovine milk contains complex oligosaccharides structurally related to those previously thought to be present in only human milk. These BMOs are microbiotic modulators involved in important biological activities, including preventing pathogen binding to the intestinal epithelium and serving as nutrients for a selected class of beneficial bacteria. Only a small number of BMO structures are fully elucidated. To better understand the potential of BMOs as a class of biotherapeutics, their detailed structure analysis is needed. This study initiated the development of a structure library of BMOs and a comprehensive evaluation of structure-related specificity. The bovine milk glycome was profiled by high-performance mass spectrometry and advanced separation techniques to obtain a comprehensive catalog of BMOs, including several novel, lower abundant neutral and fucosylated oligosaccharides that are often overlooked during analysis. Structures were identified using isomer-specific tandem mass spectroscopy and targeted exoglycosidase digestions to produce a BMO library detailing retention time, accurate mass and structure to allow their rapid identification in future studies.

Adherence inhibition of enteric pathogens to epithelial cells by bovine colostrum fractions

“…Milk from humans and nonhuman mammals contain an abundant, complex, and diverse assortment of glycans and oligosaccharides (Aldredge et al, 2013;Urashima, Saito, Nakamura, & Messer, 2001). Many of these have biological activity, influencing gut maturation (Kuntz, Kunz, & Rudloff, 2009), the immune system (Lane, O'Callaghan, Carrington, & Hickey, 2013;Rescigno & Sabatino, 2009), and the intestinal microbiota (LoCasio et al, 2007;Marcobal et al, 2010;Sela et al, 2011;Ward, Niñonuevo, Mills, Lebrilla, & German, 2007).…”

“…The separation method was already described in our previous publication (Aldredge et al, 2013). The dried samples were dissolved in 1 mL of water and diluted ten times, and 1 mL aliquots were injected.…”

“…Tri-and tetrasaccharides account for the majority of bovine milk OS. Acidic OS account for about 70% of the total content in colostrum, with sialyllactose the most abundant (Aldredge et al, 2013;Tao et al, 2009).…”

Advances in Fractionation and Analysis of Milk Carbohydrates

“…Using this method, >200 HMO structures can be separated. More recently, oligosaccharides in bovine colostrum were investigated by Aldredge et al [102], who employing nano-liquid chromatography tandem mass spectrometry, identified five fucosylated oligosaccharides that were found to be in common with human milk. Nano-LC chip/TOF MS offers an orthogonal dimension of retention time and accurate mass, making it possible to separate isomeric HMOs, with and without sialic acids, in a single-chromatographic separation.…”

Rapid Quantification of Functional Carbohydrates in Food Products

“…The compounds were extracted and matched to a BMO library [13] using the reproducible retention times and the accurate masses of each compound. The relative abundance of BMOs was determined.…”