Human Milk Glycans with degree of polymerization of 5 and 6]--3; 1--6-beta-D-Glucooligosaccharides with polymerization degree of 5-6 were obtained from laminaran and analyzed by the previously developed method [1] by using them as donors and p-nitrophenyl beta-D-glucoside as the acceptor in the transglycosylation reaction catalysed by endo-1--3-beta-D-glucanase LIV. The resulting homologous p-nitrophenyl beta-1,3-laminarioligosides with polymerization degree of 2-6 and the corresponding derivatives of mixed beta-1,3; 1,6-glucooligosaccharides with the same polymerization degree were analyzed by HPLC. The latter compounds exhibited higher retention times than the former with the same polymerization degree. Isomeric tetra-, penta-, and hexameric compounds were detected, and some of them were structurally characterized by means of NMR. The suggested method of analysis of oligosaccharide mixtures is simple, informative, and consumes a minimal quantity Rhizobium nodulation protein NodA is a host-specific determinant of the transfer of fatty acids in Nod factor biosynthesis.In the biosynthesis of lipochitin oligosaccharides (LCOs) the Rhizobium nodulation protein NodA plays an essential role in the transfer of an acyl chain to the chitin oligosaccharide acceptor molecule.

The presence of nodA in the nodABCIJ operon makes genetic studies difficult to interpret. In order to be able to investigate the biological and biochemical functions of NodA, we have constructed a test system in which the nodA, nodB and nodC genes are separately present on different plasmids. Efficient nodulation was only obtained if nodC was present on a low-copy-number vector. Our results confirm the notion that nodA of Rhizobium leguminosarum biovar viciae is essential for nodulation on Vicia. Surprisingly, replacement of R. l. by viciae nodA by that of Bradyrhizobium sp.

ANU289 results in a nodulation-minus phenotype on Vicia. Further analysis revealed that the Bradyrhizobium sp. ANU289 NodA is active in the biosynthesis of LCOs, but is unable to direct the transfer of the R. l. by, viciae nodFE-dependent multi-unsaturated fatty acid to the chitin oligosaccharide acceptor. These results lead to the conclusion that the original notion that nodA is a common nod gene should be revised.Influence of glycosidic linkages and molecular weight on the fermentation of maltose-based oligosaccharides by human gut bacteria.

2'-fucosyllactose -function study was carried out to increase knowledge of how glycosidic linkages and molecular weights of carbohydrates contribute toward the selectivity of fermentation by gut bacteria. Oligosaccharides with maltose as the common carbohydrate source were used. Potentially prebiotic alternansucrase and dextransucrase maltose acceptor products were synthesized and separated into different molecular weights using a Bio-gel P2 column. These fractions were characterized by matrix-assisted laser desorptionionization time-of-flight. Nonprebiotic maltooligosaccharides with degrees of polymerization (DP) from three to seven were commercially obtained for comparison. Growth selectivity of fecal bacteria on these oligosaccharides was studied using an anaerobic in vitro fermentation method. In general, carbohydrates of DP3 showed the highest selectivity towards bifidobacteria; however, oligosaccharides with a higher molecular weight (DP6-DP7) also resulted in a selective fermentation.

Oligosaccharides with DPs above seven did not promote the growth of beneficial bacteria. The knowledge of how specific structures modify the gut microflora could help to find new prebiotic oligosaccharides.Human Milk Oligosaccharides as a Missing Piece in Combating Nutritional Issues Cipto Mangunkusumo General Hospital, Jakarta, Indonesia.Cipto Mangunkusumo General Hospital, Jakarta, Indonesia.Extensive studies have shown that breast milk is the best source of nutrition for infants, especially during the first six months, because it fulfills almost all of their nutritional needs. Among the many functional building blocks in breast milk, human milk oligosaccharides (HMOs) have been receiving more attention recently. Furthermore, it is the third most common group of compounds in human milk, and studies have demonstrated the health benefits it provides for infants, including improved nutritional status.

HMOs were previously known as the 'bifidus factor' due to their 'bifidogenic' or prebiotic effects, which enabled the nourishment of the gastrointestinal microbiota. Healthy gastrointestinal microbiota are intestinal health substrates that increase nutrient absorption and reduce the incidence of diarrhea.