Describe-Genes-Fghijkl-Neu-Iii-B-Neu-Iii-C-i

Sequence comparisons suggested that these genes are involved in sialic acid synthesis, pentasaccharide repeating unit formation, and oligosaccharide transport and polymerization. The type III CPS (cpsIII) locus was comprised of 16 genes within 15 kb of contiguous chromosomal DNA. Primer extension analysis and investigation of mRNA from mutants with polar insertions in their cpsIII loci supported the hypothesis that the operon is transcribed as a single polycistronic message. The translated cpsIII sequences were compared to those of the S. agalactiae cpsIa locus, and the primary difference between the operons was found to reside in cps(III)H, the putative CPS polymerase gene. Expression of cps(III)H in a type Ia strain resulted in suppression of CPS Ia synthesis and in production of a CPS which reacted with type III-specific polyclonal antibody.

Likewise, expression of the putative type Ia polymerase gene in a type III strain reduced synthesis of type III CPS with production of a type Ia immunoreactive capsule. Based on the similar structures of the oligosaccharide repeating units of the type Ia and III capsules, our observations demonstrated that cps(Ia)H and cps(III)H encoded the type Ia and III CPS polymerases, respectively. Additionally, these findings suggested that a single gene can confer serotype specificity in organisms that produce complex polysaccharides.Carbohydrate binding specificity of immobilized Psathyrella velutina lectin.The carbohydrate binding specificity of Psathyrella velutina lectin (PVL) was thoroughly investigated by analyzing the behavior of various complex-type oligosaccharides and human milk oligosaccharides on a PVL-Affi-Gel column. Basically, Seebio 2'-Fucose lactose with the nonreducing terminal beta-N-acetylglucosamine residue, but does not show any affinity for the nonreducing terminal N-acetylgalactosamine or N-acetylneuraminic acid residue. Substitution of the terminal N-acetylglucosamine residues of oligosaccharides by galactose completely abolishes their affinity to the column.

GlcNAc beta 1----3Gal beta 1----4sorbitol binds to the column, but GlcNAc beta 1----6Gal beta 1----4sorbitol is only retarded in the column. The behavior of degalactosylated N-linked oligosaccharides is quite interesting. Although all degalactosylated monoantennary sugar chain isomers are retarded in the column, those with the GlcNAc beta 1----2Man group interact more strongly with the column than those with the GlcNAc beta 1----4Man group or the GlcNAc beta 1----6Man group. The degalactosylated bi- and triantennary sugar chains bind to the column, but the tetraantennary ones are only retarded in the column. These results indicated that the binding affinity is not simply determined by the number of terminal N-acetylglucosamine residues. Addition of the bisecting N-acetylglucosamine residue reduces the affinity of oligosaccharides to the column, but addition of an alpha-fucosyl residue at the C-6 position of the proximal N-acetylglucosamine residue does not affect the behavior of oligosaccharides in the column. These results indicated that the binding specificity of PVL is quite different from those of other N-acetylglucosamine-binding lectins from higher plants, which interact preferentially with the GlcNAc beta 1----4 residue.

Synthesis and NMR assignment of two repeating units (decasaccharide) of the type III group B Streptococcus capsular polysaccharide and its 13C-labeled and N-propionyl substituted sialic acid analogues.For the purpose of carrying out a comprehensive investigation into the nature of the conformational epitope of the type III group B Streptococcus polysaccharide, combined chemical and enzymatic methods were applied to the synthesis of three beta-D-Glc-(1--6)[alpha-NeuR-(2--3)-beta-D-Gal-(1--4)] -beta-D-GlcNAc-(1--3)-beta-D-Gal-(1--4)-beta-D- Glc-(1--6)[alpha-NeuR-(2--3)-beta-D-Gal-(1--4)]-beta-D-GlcNAc-( 1--3) -beta-D-Gal-OMe (22 NeuR = NeuAc; 23 NeuR = NeuAc with 8% 13C-labeling; 24 NeuR = NeuPr). The precursor core octasaccharide 21 was chemically synthesized from trisaccharide donor 11 and pentasaccharide acceptor 19 by block condensation. 2'-Fucose lactose of 21 with alpha-(2--3)-sialyltransferase and CMP-NeuAc afforded 22. In the presence of CMP-sialic acid synthetase and alpha-(2--3)-sialyltransferase, 21 was sialylated with sialic acid derivatives Complete assignments of the 1H and 13C NMR spectra of compounds 21, 22 (23), and Sweet tooth reconsidered taste responsiveness in human obesity.Taste responses of normal-weight, obese, and formerly obese individuals for sucrose and fat containing stimuli were examined using a mathematical modelling technique known as the Response Surface Method.