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Melibiose
About: Melibiose is a research topic. Over the lifetime, 1002 publications have been published within this topic receiving 27300 citations. The topic is also known as: Melibiose.
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TL;DR: The results demonstrated that highly purified RCG1 induced large cell aggregates and revealed cell-type-specific growth inhibition, and galectin-1-mediated growth inhibition was specifically suppressed by the corresponding sugar, lactose, but not by sucrose or even the structurally similar sugar, melibiose.
Abstract: Galectin-1 from American bullfrog, RCG1, was isolated to high purity, and its growth inhibitory properties against human cells were examined. The results demonstrated that highly purified RCG1 induced large cell aggregates and revealed cell-type-specific growth inhibition. It significantly inhibited all human leukemia cell lines tested such as HL-60, U937, and K562 cells but did not inhibit human colon cancer cell line, Colo 201, or mouse mammary tumor cell line FM3A cells. Although most of the galectin-induced growth inhibitions are known to be apoptic, RCG1 induced growth arrest and neither apoptosis nor necrosis. RCG1-mediated growth inhibition was specifically suppressed by the corresponding sugar, lactose, but not by sucrose or even the structurally similar sugar, melibiose. Several studies have reported that galectin-mediated biological functions were modulated by charge modification. Since the high purity of RCG1 was demonstrated but a moderate degree of growth inhibition occurred, it is possible protein charge modification was examined by isoelectric focusing, and it was found to be highly heterogeneous in charge. RCG1 binding proteins in human cells were analyzed by lectin blotting using biotinylated RCG1, and lectin blotting revealed that in human cell extracts the specific proteins at molecular weight 37 and 50 kDa possessed the responsive features of RCG1 binding and lactose competition.
01 Jan 1993
TL;DR: Results confirm the role of the multiple sugarmetabolism operon inthetransport and metabolism of melibiose, raffinose, andisomaltosaccharides in the transport andabolism of Streptococcus mutans.
Abstract: Themultiple sugarmetabolism (msm)operonofStreptococcus mutansisresponsible fortheuptake and metabolism ofavariety ofsugars.Inorder tofurther characterize thesubstrate specificities ofthetransport system, a 12-kbregion ofDNA containing theentire msm operonwas cloned, viaa novel two-step integration strategy, intothechromosomes oftwoheterologous streptococcal strains, Streptococcus gordonii Challis and Streptococcus anginosus Is57, aswell asthechromosome ofanatural isolate ofS.mutanswithadeletion ofthe msm region. Thesestrains areunable totransport orferment melibiose, raffinose, orisomaltosaccharides, but thenewlyconstructed recombinants gained theability toferment allofthese sugars.TheS.gordonii Challis construct containing msm was showntotransport radiolabelled melibiose, raffinose, isomaltotriose, and isomaltotetraose, andthetransport function was also subjected toinduction byraffinose, an inducer ofthemsm operoninS.mutans.Theresults confirm theroleofthemsm operon inthetransport andmetabolism of melibiose, raffinose, andisomaltosaccharides. Sugar fermentation plays animportant role inmaintaining Streptococcus mutansontooth surfaces, whereitcancause dental caries (11). Investigations overthepastdecade (14) haveshownthatthemajoruptake mechanism formost sugars inS.mutansisthephosphoenolpyruvate-dependent phosphotransferase system(PTS). ThePTSsugars include glucose, mannitol, sorbitol, lactose, sucrose, mannose, fructose,maltose, N-acetylglucosamine, andtrehalose. Al
TL;DR: Manninotriose undecaacetate has been prepared from melibiose as discussed by the authors, which was shown to give 6′-O-trityl-β-melibiose heptaacetate.
Abstract: Manninotriose undecaacetate has been prepared from melibiose. Tritylation of melibiose, followed by acetylation gave 6′-O-trityl-β-melibiose heptaacetate. Detritylation of the compound gave hepta-O-acetyl-β-melibiose, which was condensed with tetra-O-benzyl-D-galactopyranosyl chloride. Deacetylation of the condensation product, followed by hydrogenolysis and acetylation afforded the title compound.
01 Jan 1999
TL;DR: SAM-1095, the most potent of the glycopeptides synthesized, was resynthesized on a large scale, and this compound was assessed for in vivo pharmacology, along with the non-glycosylated version SAM-995, which demonstrates an analgesic effect similar to that of the narcotic morphine.
Abstract: The synthesis of a series of N-9-fluorenylmethoxycarbonyl (N-FMOC) protected amino acid glycosides is reported. These (1-2)-trans glycosides came directly from Koenigs-Knorr type glycosylations under Hanessian's silver triflate conditions, except for the synthesis of N-acetylgalactosamine FMOC amino acid in which silver perchlorate conditions were used to promote α-glycoside formation. The effect of D-amino acid aglycones was investigated under glucosylation conditions, and a yield dependence on amino protection was seen in the enantiomers of threonine. Due to this match vs. mismatch dichotomy, both O'Donnell Schiff bases and FMOC-amino aglycones were used in the subsequent glycosylation reactions. Glycosides were made using the monosaccharides xylose, mannose, glucose, galactose, N-acetylglucosamine, N-acetylgalactosamine, and disaccharides lactose [galactose-β-(1-4)-glucose], cellobiose [glucose-β-(1-4)-glucose] and melibiose [galactose-α-(1-6)-glucose]. All glycosides were converted to their respective FMOC-amino acid forms for direct use in solid-phase glycopeptide synthesis (SPGPS) using established methodology. A strategy into the synthesis of an FMOC-amino acid trisaccharide of Lewis ˣ (Leˣ) was also investigated in an effort to expand on the established glycoside methodology. Preliminary work with D-glucosamine and L-fucose is reported. Our synthetic rationale was based on retaining the peptide pharmacophore or message sequence constant as DCDCE (D-cys²ʼ⁵-enkephalin) with a serine-glycine tether, and making changes only in the environment of the amino-acid glycoside. Changes in amino acid, amino acid chirality, and in the sugar moiety itself would provide a stereochemical investigation into the requisite orientation and electronics for optimum blood-brain barrier (BBB) penetration, opiate receptor binding, and analgesia. Several glycopeptides were synthesized, and all were purified in both reduced and oxidized forms (if containing cysteine). A highly optimized glycopeptide synthetic strategy has been developed and will be presented and critiqued. Pharmacological analysis involving serum stability studies, BBB-penetration studies, GPI/MVD physicochemical studies and mu/delta-opiate receptor studies were completed on all glycopeptides. SAM-1095, the most potent of the glycopeptides synthesized, was resynthesized on a large scale, and this compound was assessed for in vivo pharmacology, along with the non-glycosylated version SAM-995. Preliminary results demonstrate an analgesic effect similar to that of the narcotic morphine. Assessment of all pharmacology will afford a platform for future SAR-based glycopeptide investigations.
04 Apr 2023
TL;DR: In this article , two new yeast strains designated as 20-27-1 and 20-28 were isolated from the fruiting body of Tricholoma gambosum and Marasmius maximus and were collected in Wudaogou, Weichang county, Chengde area, Hebei Province, China.
Abstract: Two new yeast strains designated as 20-27-1 and 20-28 were isolated from the fruiting body of Tricholoma gambosum and Marasmius maximus , respectively, which were collected in Wudaogou, Weichang county, Chengde area, Hebei Province, China. Analysis of the sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions showed that the two new strains differed from each other by one nucleotide substitutions in the D1/D2 domains and were identical in the ITS regions. The combined ITS and D1/D2 sequences phylogenetic analysis showed that the two strains were closely related to Nakazawaea ernobii and Nakazawaea holstii and differed from them by 99.3% (substitution: deletion 3: 1) and 98.7% (substitution: deletion 6: 1) similarity in D1/D2 domains, respectively. About 97.1% similarity of ITS sequences was presented between the two new strains and the two known species. Physiologically, those two new strains differed from N. ernobii and N. holstii by assimilation of melibiose, inulin, D-glucosamine, soluble starch and DL-lactate. The phenotypic and phylogenetic analyses indicated that those two strains represent a novel species of the genus Nakazawaea . Therefore, the name Nakazawaea tricholomae sp. nov. was proposed for those two strains. The holotype is deposited in China General Microbiological Culture Collection Center as CGMCC 2.7006 . The new species name is registered in Fungal Names as FN 571492.