A selective method for sequential splitting of O- and N-linked glycans from N,O-glycoproteins.

O-Linked oligosaccharides from N,O-glycoproteins were selectively split off by treatment with alkaline sodium borohydride in the presence of cadmium salt. The side reaction of reductive cleavage of N-glycosylamide and peptide bonds, observed under standard conditions of splitting of O-linked chains (M NaBH4 and 50mM NaOH, 16 h, 50 degrees), was inhibited by addition of 50-10 mM cadium acetate and 5-10mM EDTA.Na4, as shown by treatment of model compounds and several glycoproteins (ovomucoid, group-specific glycoproteins H and B, fetuin, and asialofetuin). This treatment, in combination with the previously developed procedure for the release of the N-linked oligosaccharide chains by lithium borohydride, allows a sequential, selective cleavage of O-, and then N-linked oligosaccharides from N,O-glycoproteins by chemical methods.     

A convenient synthesis of 1,2-O-benzylidene and 1,2-O-ethylidene derivatives of carbohydrates

N.m.r., enzymic, and chemical techniques have been used to characterise the d-galactose-containing tri- and tetra-saccharides produced on hydrolysis of carob and L. leucocephalad-galacto-d-mannans by Driselase β-d-mannanase. These oligosaccharides were shown to be exclusively 6¹-α-d-galactosyl-β-d-mannobiose and 6¹-α-d-galactosyl-β-d-mannotriose. Furthermore, these were the only d-galactose-containing tri- and tetra-saccharides produced on hydrolysis of carob d-galacto-d-mannan by β-d-mannanases from other sources, including Bacillus subtilis, Aspergillus niger, Helix pomatia gut solution, and germinated legumes. Acid hydrolysis of lucerne galactomannan yielded 6¹-α-d-galactosyl-β-d-mannobiose and 6²-α-d-galactosyl-β-d-mannobiose.     

A new synthesis of 6-N-hydroxy-4-(2-methyl-l,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-ylmethyl)benzamide, tubastatin a, a highly selective inhibitor of histone deacetylase

A highly selective inhibitor of histone deacetylase 6, tubastatin A, was synthesized in four steps under smooth and safe reaction conditions.     

Leishmania donovani: structural insignt in the recognition of C-methylated analogues of spermidine as natural polyamine

The ability of alpha-, beta-, gamma- and omega-methylated spermidine analogues to restore the growth of L. donovani promastigotes that were depleted of putrescine and spermidine was investigated. Only beta-methylated spermidine, like natural spermidine was capable of restoring the growth of L. donovani, while the remaining three analogues turned out to be inactive. Considering that alpha-methylated spermidine is a functionally active spermidine surrogate both in vivo and in vitro, this analogue can be considered as an antidote in the host-parasite system, especially in cases where inhibitors of polyamine biosynthesis are used for the therapy of leishmaniasis.     

Rhizosphere strain of <Emphasis Type="Italic">Pseudomonas chlororaphis</Emphasis> capable of degrading naphthalene in the presence of cobalt/nickel

Combination of genetic systems of degradation of polyaromatic hydrocarbons, resistance to heavy metals, and promotion of plant growth/protection is one of the approaches to the creation of polyfunctional strains for phytoremediation of soils after co-contamination with organic pollutants and heavy metals. A plant-growth-promoting rhizosphere strain Pseudomonas chlororaphis PCL1391 (pBS216^*, pBS501) has been obtained, in which the nah operon of plasmid pBS216 provides naphthalene biodegradation and the cnr-like operon of plasmid pBS501 provides resistance to cobalt and nickel due to the extrusion of heavy metal cations from the cells. In the presence of 100 μM of nickel, the viability, growth rate, and naphthalene biodegradation efficiency of the resistant strain PCL1391 (pBS216^*, pBS501) were much higher as compared with the sensitive PCL1391 (pBS216). During the growth of the resistant strain, in contrast to the sensitive strain, nickel (100 μM) had no inhibiting effect on the activity of the key enzymes of naphthalene biodegradation. Original Russian Text ? T.V. Siunova, T.O. Anokhina, A.V. Mashukova, V.V. Kochetkov, A.M. Boronin, 2007, published in Mikrobiologiya, 2007, Vol. 76, No. 2, pp. 212–218.     

Antigenic polysaccharides of bacteria. 17. The structure of O-specific polysaccharide chain of Pseudomonas aeruginosa X (Meitert) lipopolysaccharide

O-Specific polysaccharide composed of L-rhamnose and 2-acetamido-2-deoxy-D-mannose was obtained on mild acid degradation of P. aeruginosa X (Meitert classification) lipopolysaccharide. On the basis of non-destructive analis using 1H, 13C NMR spectroscopy and Klyne's rule calculation, as well as chemical methods (acid hydrolysis, methylation, Smith degradation), it was established that the polysaccharide is built up of disaccharide repeating units of the following structure: ----4)-alpha-L-Rha-(1----3)-beta-D-ManNAc-(1----.