Epi Taufik

Recent Advances in Studies on Milk Oligosaccharides of Cows and Other Domestic Farm Animals

Human mature milk and colostrum contain 12-13 g/L and 22-24 g/L of milk oligosaccharides respectively, and the structures of least 115 human milk oligosaccharides (HMOs) have been characterized to date. By way of comparison, bovine colostrum collected immediately post partum contains only around 1 g/L of oligosaccharides, and this concentration rapidly decreases after 48 h. It was recently recognized that HMOs have several biological functions, and this study area has become very active, as illustrated by a recent symposium, but it appears that advances in studies on the milk oligosaccharides of domestic farm animals, including cows, have been rather slow compared with those on HMOs. Nevertheless, studies on bovine milk oligosaccharides (BMOs) have progressed recently, especially in regard to structural characterization, with the development of methods termed glycomics. This review is concerned with recent progress in studies on the milk oligosaccharides of domestic farm animals, especially of BMOs and bovine glycoproteins, and it discusses the possibility of industrial utilization in the near future.

Structural characterization of neutral and acidic oligosaccharides in the milks of strepsirrhine primates: greater galago, aye-aye, Coquerel’s sifaka and mongoose lemur

The structures of milk oligosaccharides were characterized for four strepsirrhine primates to examine the extent to which they resemble milk oligosaccharides in other primates. Neutral and acidic oligosaccharides were isolated from milk of the greater galago (Galagidae: Otolemur crassicaudatus), aye-aye (Daubentoniidae: Daubentonia madagascariensis), Coquerel’s sifaka (Indriidae: Propithecus coquereli) and mongoose lemur (Lemuridae: Eulemur mongoz), and their chemical structures were characterized by 1H-NMR spectroscopy. The oligosaccharide patterns observed among strepsirrhines did not appear to correlate to phylogeny, sociality or pattern of infant care. Both type I and type II neutral oligosaccharides were found in the milk of the aye-aye, but type II predominate over type I. Only type II oligosaccharides were identified in other strepsirrhine milks. α3′-GL (isoglobotriose, Gal(α1-3)Gal(β1-4)Glc) was found in the milks of Coquerel’s sifaka and mongoose lemur, which is the first report of this oligosaccharide in the milk of any primate species. 2′-FL (Fuc(α1-2)Gal(β1-4)Glc) was found in the milk of an aye-aye with an ill infant. Oligosaccharides containing the Lewis x epitope were found in aye-aye and mongoose lemur milk. Among acidic oligosaccharides, 3′-N-acetylneuraminyllactose (3′-SL-NAc, Neu5Ac(α2-3)Gal(β1-4)Glc) was found in all studied species, whereas 6′-N-acetylneuraminyllactose (6′-SL-NAc, Neu5Ac(α2-6)Gal(β1-4)Glc) was found in all species except greater galago. Greater galago milk also contained 3′-N-glycolylneuraminyllactose (3′-SL-NGc, Neu5Gc(α2-3)Gal(β1-4)Glc). The finding of a variety of neutral and acidic oligosaccharides in the milks of strepsirrhines, as previously reported for haplorhines, suggests that such constituents are ancient rather than derived features, and are as characteristic of primate lactation is the classic disaccharide, lactose.

Chemical characterization of milk oligosaccharides of the eastern quoll (Dasyurus viverrinus)

Structural characterizations of marsupial milk oligosaccharides have been performed in four species to date: the tammar wallaby (Macropus eugenii), the red kangaroo (Macropus rufus), the koala (Phascolarctos cinereus) and the common brushtail possum (Trichosurus vulpecula). To clarify the homology and heterogeneity of milk oligosaccharides among marsupials, the oligosaccharides in the carbohydrate fraction of eastern quoll milk were characterized in this study. Neutral and acidic oligosaccharides were separated and characterized by 1H-nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The structures of the neutral oligosaccharides were Gal(β1–3)Gal(β1–4)Glc (3’-galactosyllactose), Gal(β1–3)Gal(β1–3)Gal(β1–4)Glc (3”,3’-digalactosyllactose), Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novopentaose I), Gal(β1–3)Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (galactosyl lacto-N-novopentaose I), Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–3)Gal(β1–4)Glc (galactosyl lacto-N-novopentaose II), Gal(β1–3)[Gal(β1–3)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (galactosyl lacto-N-novopentaose III) and Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novooctaose). The structures of the acidic oligosaccharides detected are Neu5Ac(α2–3)Gal(β1–4)Glc (3’-sialyllactose), Gal(β1–3)(O-3-sulfate)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novopentaose I sulfate a), Gal(β1–3)[Gal(β1–4)(O-3-sulfate)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto-N-novopentaose I sulfate b), Neu5Ac(α2–3)Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyl lacto-N-novopentaose a), Gal(β1–3)[Neu5Ac(α2–3)Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (sialyl lacto-N-novopentaose c), Neu5Ac(α2–3) Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc, and Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc with an α(2–3) Neu5Ac linked to β(1–4)Gal residue of either branch of Gal(β1–4)GlcNAc(β1–6) units. The most predominant oligosaccharides in the carbohydrate fraction of mid-lactation milk were found to be lacto-N-novopentaose I and lacto-N-novooctaose, i.e., branched oligosaccharides that contain N-acetylglucosamine. The predominance of these branched oligosaccharides, rather than of a series of linear β(1–3) linked galacto oligosaccharides, appears to be the main feature of the eastern quoll milk oligosaccharides that differentiates them from those of the tammar wallaby and the brushtail possum.