The first committed enzyme in GDP-L-fucose formation from GDP-D-mannose is GDP-D-mannose 4,6-dehydratase, which forms GDP-4-keto-6-deoxy-D-mannose. The uncertain enzymatic steps beyond this point were examined in this study. Assays were developed for the epimerase and reductase activities which the putative pathway would predict. A protein was isolated exhibiting homogeneity by several criteria...

A positive selectable marker system was adapted for transformation of mature embryo-derived calli of Indica rice (Oryza sativa L.) utilizing the PMI gene encoding for phosphomannose-isomerase that converts mannose-6-phosphate to fructose-6-phosphate. The transformed cells grew on medium supplemented with 3% mannose as carbon source and calli were selected on media containing various concentrati...

Twenty-four mutacin-producing Streptococcus mutans strains were screened for their propensity to produce class II one-peptide bacteriocin using a deferred antagonism assay. Streptococcus salivarius and 3 mutants defective in their mannose phosphotransferase systems (mannose-PTS) were used as sensitive strains to identify which mannose-PTS could act as the docking site for class II one-peptide b...

An enzyme system from fruits of the flax plant is described that catalyzes the synthesis of the sugar nucleotide guanosine 5'-diphosphate l-fucose from guanosine 5'-diphosphate d-mannose with the intermediate formation of guanosine 5'-diphosphate 4-keto-6-deoxy-d-mannose. Tritium from-[(3)H]H(2)O was incorporated into the l-fucose portion of the sugar nucleotide in the course of the reaction, a...

In the interest of classifying cases of male factor infertility, we have paid particular attention to the sugar ligand binding properties of the human sperm surface and the functional capacity of the acrosome for exocytosis--key parameters for assessing sperm fertilizing ability. Zona recognition and binding involve the interactions of sperm surface mannose receptors (lectins) with mannose liga...

OBJECTIVE Upregulated expression of endothelial adhesion molecules and subsequent binding to cognate monocytic receptors are established paradigms in atherosclerosis. However, these proteins are the scaffolds, with their posttranslational modification with sugars providing the actual ligands. We recently showed that tumor necrosis factor-α increased hypoglycosylated (mannose-rich) N-glycans on ...

1. A lactating rabbit mammary-gland microsomal system catalysed the incorporation of mannose from GDP-[U-14C]mannose into three endogenous acceptors, (i) polyprenyl phosphate mannose, (ii) lipid-linked oligosaccharide and (iii) protein. 2. Synthesis of polyprenyl phosphate mannose was stimulated by addition of dolichol phosphate to the incubation medium and was reversed by addition of GDP. The ...

The macrophage mannose receptor (MMR) is a 175-Kd cellsurface transmembrane glycoprotein that is expressed on tissue macrophages where it functions both to mediate the uptake of mannose-rich glycoproteins and as a phagocytic receptor for bacteria, yeasts, and other pathogenic microorganisms. In this report we describe the cloning of the full-length cDNA of the mouse macrophage mannose receptor ...

Upon intravenous injection into rats, the plant toxin ricin was rapidly cleared from the circulation by the liver. Among the different liver cell populations, most of the injected ricin associated with the sinusoidal endothelial cells (EC), whereas the liver parenchymal cells (PC) and Kupffer cells (KC) yielded minor contributions to the total liver uptake in vivo. Co-injection of mannan strong...

Many mannose-binding proteins inhibit divergent strains of human immunodeficiency virus type 1 (HIV-1) in in vitro models of viral infectivity, suggesting that targeting mannose residues in vaccine applications might offset the strain restriction typically observed in antibody responses to HIV vaccine preparations. Concanavalin A (ConA) behaves like neutralizing antibodies that do not interfere...