Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture & Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan,
Glycoconj J. 2013 Nov;30(8):801-11. doi: 10.1007/s10719-013-9484-8. Epub 2013 Jul 4.
Previous structural characterizations of marsupial milk oligosaccharides had been performed in only two macropod species, the tammar wallaby and the red kangaroo. To clarify the homology and heterogeneity of milk oligosaccharides among marsupial species, which could provide information on their evolution, the oligosaccharides of the koala milk carbohydrate fraction were characterized in this study. Neutral and acidic oligosaccharides were separated from the carbohydrate fraction of milk of the koala, a non-macropod marsupial, and characterized by (1)H-nuclear magnetic resonance spectroscopy. The structures of the neutral saccharides were found to be Gal(β1-4)Glc (lactose), 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) and Gal(β1-3){Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6)}Gal(β1-4)Glc (fucosyl lacto-N-novopentaose I), while those of the acidic saccharides were Neu5Ac(α2-3)Gal(β1-4)Glc (3'-SL), Neu5Ac(α2-3)Gal(β1-3)Gal(β1-4)Gal (sialyl 3'-galactosyllactose), 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(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyl lacto-N-novopentaose b), Gal(β1-3)[Neu5Ac(α2-3)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyl lacto-N-novopentaose c), and Neu5Ac(α2-3)Gal(β1-3){Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6)}Gal(β1-4)Glc (fucosyl sialyl lacto-N-novopentaose a). The neutral oligosaccharides, other than fucosyl lacto-N-novopentaose I, a novel hexasaccharide, had been found in milk of the tammar wallaby, a macropod marsupial, while the acidic oligosaccharides, other than fucosyl sialyl lacto-N-novopentaose a had been identified in milk carbohydrate of the red kangaroo. The presence of fucosyl oligosaccharides is a significant feature of koala milk, in which it differs from milk of the tammar wallaby and the red kangaroo.
先前对有袋目动物奶寡糖的结构特征研究仅在两种有袋目大型动物物种，即短尾矮袋鼠和红袋鼠中进行过。为了阐明有袋目动物物种之间奶寡糖的同源性和异质性，这可能为它们的进化提供信息，本研究对考拉奶碳水化合物部分的寡糖进行了表征。从非大型有袋目有袋动物考拉的奶碳水化合物部分中分离出中性和酸性寡糖，并通过（1）H 核磁共振波谱进行了表征。发现中性糖的结构为 Gal(β1-4)Glc（乳糖）、Gal(β1-3)Gal(β1-4)Glc（3'-半乳糖基乳糖）、Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc（3',3″-二半乳糖基乳糖）、Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc（乳糖-N-新戊四糖 I）和 Gal(β1-3){Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6)}Gal(β1-4)Glc（岩藻糖基乳糖-N-新戊四糖 I），而酸性糖的结构为 Neu5Ac(α2-3)Gal(β1-4)Glc（3'-SL）、Neu5Ac(α2-3)Gal(β1-3)Gal(β1-4)Gal（唾液酸 3'-半乳糖基乳糖）、Neu5Ac(α2-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc（唾液酸乳糖-N-新戊四糖 a）、Gal(β1-3)[Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc（唾液酸乳糖-N-新戊四糖 b）、Gal(β1-3)[Neu5Ac(α2-3)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc（唾液酸乳糖-N-新戊四糖 c）和 Neu5Ac(α2-3)Gal(β1-3){Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6)}Gal(β1-4)Glc（岩藻糖基唾液酸乳糖-N-新戊四糖 a）。除了岩藻糖基乳糖-N-新戊四糖 I 之外，中性寡糖，一种新的六糖，在有袋目大型动物短尾矮袋鼠的奶中被发现，而除了岩藻糖基唾液酸乳糖-N-新戊四糖 a 之外的酸性寡糖，在红袋鼠的奶碳水化合物中被鉴定出来。岩藻糖基寡糖的存在是考拉奶的一个显著特征，这使其与短尾矮袋鼠和红袋鼠的奶不同。
