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Sialic acid, which occurs at the non reducing ends of carbohydrate moieties of animal glycoproteins and gangliosides, and of free oligosaccharides in milk colostrum, 1 3) has many biological functions. 4) It is generally considered that sialic acid inhibits the attachment of pathogenic viruses, bacteria and bacterial toxins to the epithelial cells in the colon, bronchus and lung, etc. 5,6) and that sialic acid in brain gangliosides participates in synaptogenesis and neural transmission. 3,7) As sialic acid is also contained in carbohydrate moieties of the glycoconjugates in foods, including milk or colostrums, 8 11) both infants and adults consume sialic acid in their diets. Wang and Brand Miller have suggested that sialic acid from glycoconjugates of milk may be absorbed in the infant small intestine and be used for brain ganglioside formation. 3,7)The absorption of sialic acid in the small intestine has not, however, been fully established to date.In this study, we fed sialyllactose, which has been found in bovine colostrum and cheese whey, or galactosylated N acetylneuraminic acid, which had been synthesized as described in our previous study, 12) to adult rats, and studied their swimming learning behavior and brain lipid composition. MATERIAL AND METHODS Materials.Free N acetylneuraminic acid (Neu5Ac) was commercially obtained from Snow Brand Milk Products Co., Ltd. Galactosylated N acetylneuraminic acid (GN) was synthesized from Neu5Ac and lactose with Bacillus circulans β galactosidase as described in our previous paper.12) GN was a mixture of Gal(β1 8)Neu5Ac (45%), Gal(β1 9)Neu5Ac (45%) and Gal(β1 3)Gal(β1 8) Neu5Ac (10%). Sialyllactose (SL) was separated from cheese whey as follows. 13,14) Cheese whey (1500 kg) was concentrated by evaporation and the lactose partially removed by crystallization. The supernatant was passed through an anion exchange resin (Dowex 1 × 4), which was then eluted with a large volume of water to wash out non acidic solutes. The SL, which had been adsorbed by the resin, was eluted using a linear gradient of 0 0.06 M sodium acetate. The eluate was deionized using electron dialysis and lyophilized to obtain 96% pure SL of which 87% was Neu5Ac(α2 3)Gal(β1 4)Glc and 13% was Neu5 Ac(α2 6)Gal(β1 4)Glc, as determined by high performance liquid chromatography. Galactooligosaccharide (GL) was prepared by a transglycosylation reaction catalyzed by Aspergillus oryzae β galactosidase according to the method of Deya et al .15) The GL was purified by charcoal column chromatography. The composition of GL was 75% trisaccharide, 20% tetrasaccharide and 5% pentasaccharide. The main structure was Gal(β1 6)Gal(β1 4)Glc.Animals and Diets. Thirty six male Sprague Dawley (SD) rats (8 weeks: Charles River Inc.), with an initial mean weight of 300 g, were housed under controlled ambient temperature (22±2 C) conditions with 55±5% humidity and lighting (light cycle from to 12 h) with free access to food and water. The control group (n=6) was fed the AIN 96G (Oriental Yeast Co., Ltd.) diet while the treated...

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SummaryLactitol-oligosaccharide (LO) was prepared from lactitol by transglycosylation reaction with Aspergillus oryzae ƒÀ-galactosidase.

Staphylococcal enterotoxin H (SEH) is predicted to be involved in staphylococcal food poisoning. To characterize SEH-producing Staphylococcus aureus isolates from staphylococcal food poisoning cases in Japan, we investigated the relationship between SEH production and coagulase serotype, which is an epidemiological marker, and compared the properties of SEH production with those of staphylococcal enterotoxins A (SEA) and B (SEB). SEH production was determined by a newly developed sandwich enzyme-linked immunosorbent assay. Eighty-six (59.7%) of 144 isolates from staphylococcal food poisoning cases produced SEH. Seventy-one of the SEH-producing isolates simultaneously produced SEA, SEB, or both. All SEH-producing isolates belonged to coagulase type VII, which was the predominant type, representing 99 (68.8%) of 144 isolates. The amount of SEH produced in brain heart infusion was almost the same as the amount of SEA and approximately 10-fold lower than that of SEB. SEH and SEA were produced mainly during the late exponential phase of growth, whereas SEB was produced mostly during the stationary phase. The production levels of SEH and SEA were gradually affected by decreases in water activity, but the production of SEB was greatly reduced under conditions of low water activity. These findings indicate that SEH-producing S. aureus isolates are of high prevalence in staphylococcal food poisoning cases. Given the unique epidemiological characteristic of these isolates, SEH and SEA probably are responsible for food poisoning.