Removal Of Sugars Research Articles

A spoonful of sugar helps the medicine go down? Perspectives on the use of sugar in children's medicines

This analysis examines the policy issues involved in the removal of sugar from paediatric medicines. It reports a study which investigates the perspectives of professionals, consumers, and the pharmaceutical industry. Interviews were conducted with: parents of children receiving long term medication, dental professionals involved in influencing policy or caring for such children, and drug companies who produce medication for long term use by children. Results showed that the parent group preferred the tablet over the liquid form of medication; this was also considered acceptable by the key dental professionals interviewed. The removal of sugar from liquid medicine (rather than the alternative use of smaller tablets) was not therefore a policy generally preferred by the groups involved in the issue. It was concluded that the singular concern of the dentist, doctors and pharmacists to remove sugar from liquid paediatric medicines was a reflection of their altruistic intentions. The limited biomedical perspective of clinically trained occupations prevented them from exploring the wider issues of the various needs of consumers. Thus, the analysis highlights the problems which have been introduced by professional dominance in the issue of medication caries.

A novel, glycan-dependent epitope in the V2 domain of human immunodeficiency virus type 1 gp120 is recognized by a highly potent, neutralizing chimpanzee monoclonal antibody.

An anti-gp120 monoclonal antibody (MAb), C108G (gamma 1, kappa), was isolated from a chimpanzee that had been infected with strain IIIB of human immunodeficiency virus type 1 (HIV-1IIIB) and subsequently immunized with the recombinant glycoprotein rgp160MN. This MAb is specific for the IIIB strain of HIV-1 and related clones and exhibits very potent neutralization of these viruses; e.g., 100% neutralization of approximately 8 x 10(3) infectious units of HXB2 was achieved with 125 ng of C108G per ml. Commensurate with this potent neutralizing activity, the apparent affinity of C108G for rgp160LAI was very high, i.e., approximately 3 x 10(10) liters/mol. The C108G epitope was not destroyed by reduction of gp120 disulfide bonds but was profoundly disrupted by removal of N-linked sugars from gp120. Despite the importance of a glycan(s) in forming the C108G epitope, specific binding of C108G to synthetic peptides overlapping in amino acids 162 to 169 of the V2 region was detected, albeit with an affinity approximately 2,000-fold lower than that of C108G's binding to glycosylated envelope protein. This epitope mapping correlated with results of competition assays using MAbs of known epitope specificities. To our knowledge, this is the first description of an anti-V2 MAb raised in response to HIV-1 infection. Its potent neutralizing activity and epitope specificity indicate that the V2 domain of gp120 may be an effective target of the protective immune response and, therefore, potentially an important component of HIV vaccines.

Vinculin is a major platelet protein that undergoes Ca2+-dependent tyrosine phosphorylation

When intracellular Ca2+ pools are released during platelet stimulation by thrombin, elevation of platelet cytosolic Ca2+ concentration induces tyrosine phosphorylation of a 130 kDa protein, and refilling the pools mediates dephosphorylation of this protein [Vostal, Jackson and Shulman (1991) J. Biol. Chem. 266, 16911-16916]. In the present work the 130 kDa protein was identified as vinculin by the following criteria. (1) It is detected on protein immunoblots of thrombin-activated platelets by both monoclonal anti-phosphotyrosine and anti-vinculin antibodies. (2) Removal of N-linked sugars with peptide-N-glycosidase or reduction did not change the molecular mass of vinculin or of the 130 kDa protein on SDS/PAGE. (3) The 130 kDa tyrosine-phosphorylated protein associates with Triton-soluble fraction of platelets as does vinculin. (4) The 130 kDa protein immunoprecipitated by anti-vinculin monoclonal antibody reacts with anti-phosphotyrosine antibody; when immunoprecipitated by anti-phosphotyrosine antibody it reacts with anti-vinculin antibody. (5) The 130 kDa tyrosine-phosphorylated protein and vinculin focus isoelectrically at pI 5.4-5.8. Our finding that vinculin is a major platelet protein that undergoes Ca(2+)-dependent tyrosine phosphorylation during platelet activation may provide clues to the function of this protein.

The use of enzyme recycling and the influence of sugar accumulation on cellulose hydrolysis by Trichoderma cellulases

The enzymatic hydrolysis of cellulose was initially investigated using the alkaline peroxide-treated fraction derived from steam-exploded Eucalyptus viminalis chips and a cellulase mixture of the commercial Celluclast and Novozym preparations. Nearly complete saccharification of the substrate was obtained when hydrolysis was carried out at a substrate concentration of 6% (w/v) and an enzyme loading of 10 FPU g −1 of cellulose. Lower rates of hydrolysis were observed when high sugar concentrations accumulated in the reaction mixture. The removal of soluble sugars liberated during hydrolysis enhanced the efficiency of hydrolysis of the residual substrate. Most of the cellulase activity was shown to be associated with the undydrolyzed residue. The enzyme mixture used to obtain complete hydrolysis of the substrate at a 2% (w/v) concentration was successfully recycled for five consecutive steps, with an elapsed time of 48 h between each recycling step. This same enzyme preparation could be reused an additional four times if the duration of hydrolysis was extended to 120 h; however, the efficiency of cellulose hydrolysis gradually decreased with each subsequent recycling step.

Lactic acid fermentation influence on sugar content and colour of deep-fried carrot chips

Carrot chips with a light red-yellow colour were obtained by lactic acid fermentation of carrot slices in a brine prior to deep-frying. The fermentation process decreased the content of reducing sugars up to 75%, thereby restricting the extent of Maillard reactions during heating. Rinsing the slices after fermentation but prior to deep-frying enhanced sugar removal. Three strains of Lactobacillus were tested. Strain NCIMB 40450 reduced sugar levels faster than strains NCDO 1193 and NCDO 1752. The best colour properties were obtained when carrot slices were deep-fried after 24 h fermentation.

Role of carbohydrate moieties in cross-reactivity between different components of Parietaria judaica pollen extract.

Cross-reactivity between the different components in Parietaria judaica pollen extract has been investigated by polyclonal as well as monoclonal antibodies before and after chemical deglycosylation obtained by trifluoromethanesulphonic acid (TFMS) treatment of the extract. In western blotting a polyclonal rabbit antiserum, obtained by injecting purified Par j I, was able to recognise many components of the native extract. However, its reactivity was restricted, after chemical deglycosylation of the extract, to the major allergen alone, indicating that its cross-reactivity was due to sugar moieties. Moreover, out of several monoclonal antibodies raised by injecting the whole Parietaria judaica extract, one (1A4/2F8) was also able in western blotting to recognise an epitope shared by many components of the extract except the major allergen Par j I. However, in this case the broad reactivity of the antibody was not affected by the deglycosylating procedure. When the reactivity of Parietaria judaica extract was tested before and after sugar removal, against specific IgE from a pool of patient sera, no differences could be demonstrated, thus indicating that carbohydrates are not strongly involved in the binding of Parietaria judaica-specific IgE. The results indicate that both proteic and carbohydratic cross-reactive epitopes are shared by many components of Parietaria judaica pollen extract.

Potential reduction of nonstructural carbohydrate losses by juice expression prior to ensiling sweet sorghum

Both the nonstructural carbohydrate (sugar) and structural carbohydrate (fiber) components of sweet sorghum must be collected and utilized, if it is to be competitive as an ethanol feedstock. Sugar collected in juice expressed from chopped whole stalks equaled 42% of whole-stalk sugar. Potential increase in press performance resulting from removal of a rind-leaf function was investigated. A fractionation ratio of 0.25 (rind-leaf fraction equal to 25% whole-stalk mass separated prior to juice expression) gave maximum collection of sugar in the juice. Collected sugar was 52% of whole-stalk sugar. Extraction ratio (mass of juice divided by input mass) increased from 0.36 for chopped whole stalks to 0.60 for the 0.25 fractionation ratio ( F r = 0.25) sorghum. For higher fractionation ratios, the increase in extraction ratio was not sufficient to offset sugar loss due to rind-leaf removal. Assuming press capacity (Mg h −1) is the same for both chopped whole-stalk and F r = 0.25 sorghum, press performance (juice sugar collected per h) will increase by 67%. Removal of juice sugar reduced expected sugar conversion during ensiling from 92% of initial sugar (chopped whole stalk) to 40% (combination silage produced from residues from F r = 0.25 processing). An expression was derived to calculate nonstructural carbohydrate (NC) content of combination silage produced by combining the pith presscake and rind-leaf fractions. Minimum NC occurred for F r = 0.25.

Effects of processing on the oligosaccharides of oilseed and legume protein meals

The effects of (alkanol)-hexane, (alkanol/water)-hexane and (alkanol/ammonia/water)-hexane extraction systems on the removal of low-molecular-weight sugars from soybean, cottonseed, field pea and mung bean were studied. The total content of soluble sugars of hexane-extracted meals varied between 4.79 and 12.12%, depending on the type of seed and solvent extraction system used. The predominant sugar of cottonseed was raffinose. Sucrose and stachyose were present in smaller quantities. However, glanded cottonseed contained about four times more stachyose than glandless seeds. Seeds were extracted with methanol, ethanol and isopropanol, with or without 10% (w/w) ammonia, possibly containing 50% (v/v) water. The above extraction systems removed up to 81% of the total flatulence-causing sugars. Methanol was the most effective alkanol used, while isopropanol exhibited the poorest extraction efficiency. (Methanol/ammonia)-treated meals contained from 0.38 to 2.86% raffinose; however, all extraction systems were less effective in removing stachyose and verbascose. Results of this study imply that the removal of flatulence-causing sugars depends on their molecular weight, the seed's structural parameters, interaction within the seed components and polarity of the solvent systems used.

Stripping interfering sugars from samples using adapted bacteria

Bacteria adapted to individual sugars quickly remove targeted sugars — stripping them — from samples in which unwanted sugars interfere. Adapted bacteria are equivalent to specific reagents for removal of sugars down to bacterial Km values, micromolar to submicromolar concentrations. Bacterial stripping is a simple method, useful when background sugars in micro-to millimolar concentrations (or larger) interfere with analysis of sought-for sugars. Bacteria such as Escherichia coli and Klebsiella are easily adapted to individual sugars such as lactose, fructose, etc., by growing the bacteria on them. Hence one can easily create (and store) many kinds of cells ready to sponge up or strip out unwanted compounds. E. coli specifically remove several sugars from samples containing 100–500 nmol of sugars, using 1–5 mg of adapted cells, and 25°C temperatures. Stripping requires 1–5 min and consists of mixing cells and sample, spinning down the cells, and withdrawal of stripped supernate. A 1–5 min interval is adequate for uptake and stripping, but far too short for cells to metabolize the sugars that were taken up. Hence the cells do not leak metabolites, but act as specific adsorbants without injection of appreciable byproducts into the sample.

Differential regulation by trophic conditions of phosphorylating and non-phosphorylating NADP +-dependent glyceraldehyde-3-phosphate dehydrogenases in Chlorella fusca

The two NADP +-dependent glyceraldehyde-3-phosphate dehydrogenases present in the green alga Chlorella fusca, namely, the phosphorylating (chloroplastic) enzyme and the non-phosphorylating (cytosolic) enzyme, are differently affected by the trophic conditions prevailing in the cell cultures. The addition of metabolizable sugars to cell cultures growing in the light promotes a marked decrease of the phosphorylating enzyme activity down to a barely detectable cellular level. In contrast, the cellular level of the non-phosphorylating enzyme is even enhanced in the presence of such sugars. These effects are not observed, however, with a number of non-assimilable sugar analogs. After sugar removal, a recovery of the phosphorylating activity-in a process which is inhibited by cycloheximide but not by lincomycin- is observed in illuminated cells but not in darkness, thus indicating a light-dependent nuclear synthesis of the chloroplastic enzyme. It seems therefore that the two dehydrogenases are adaptative enzymes subject to differential regulation by nutritional conditions.

Removal of Flatulence-Causing Sugars from Legumes and Oilseeds

The frequency response (FR) of the large-scale power system shows significant frequency spatial distribution characteristics (FSDC), still using uniform frequency models may cause large errors in the FR solution, and the FSDC should be preserved in the modeling. In this paper, a three-machine equivalent system frequency response (TM-SFR) model is proposed to preserve the FSDC by the parameter equivalent aggregation method, including load, network, and generator. The TM-SFR model is further simplified into a solvable forced vibration equation by loop-opening and approximation, and its closed-form solution (CFS) is obtained by the modal superposition method, to analytically solve the FR following a major disturbance. Case studies are introduced to verify the performance of the TM-SFR model and its CFS over the WSCC 9-bus system, the New England 39-bus system, and the IEEE 118-bus system. The results prove that the proposed model can preserve the intermachine frequency oscillation caused by the FSDC in various scenarios, and improve the FR solution accuracy at high solution speed, which can provide a more reliable basis for frequency stability emergency control.

Selective Removal of Sugars from Aqueous Solutions by Adsorption on Precipitated Iron(III) Hydroxide

Abstract The removal of various mono-, di-, oligo-, and poly-saccharides from aqueous solutions by adsorptive binding to precipitated iron(III) hydroxide was very selective in respect of their stereo-chemistry and chain length.

Immunosuppressive activity of tamm-horsfall glycoprotein oligosaccharides: Effect of removal of outer sugars and conjugation with a protein carrier

Tamm-Horsfall (TH) glycoprotein, the major protein of human urine, is, in vitro, a powerful immunosuppressive agent and the activity resides in its oligosaccharide chains. In this study we investigated structural features required for the inhibitory activity of TH glycoprotein oligosac-charides in the one-way mixed lymphocyte reaction (MLR). We found that both high-mannose and complex-type TH glycopeptides, fractionated from Pronase-digested TH glycoprotein, behaved as inhibitors. Sequential exoglycosidase digestion of complex-type TH glycopeptide results in a slight increase of the inhibitory activity, with a maximum after desialylation and β-galactosidase treatment. These results suggest that the immunosuppressive activity resides in the central portion of TH glycoprotein N-linked oligosaccharides. The conjugation of complex-type TH glycopeptides to a protein carrier, such as bovine serum albumin, greatly enhanced the inhibitory activity. This effect occurred if the TH-glycopeptide conjugate was added to MLR within the first 24 hr. These results indicate that (i) the immunosuppressive activity is strongly dependent on a multivalent interaction between TH oligosaccharides and ligand(s) at the lymphocyte surface; (ii) an early step of cell-cell recognition is the target of the immunosuppressive conjugate; (iii) TH oligosaccharides compete with a carbohydrate recognition system between effector and stimulator cells which contributes to the MLR-induced blastogenesis.

Effect of cocultivation of ruminal chytrid fungi with Methanobrevibacter smithii on lucerne stem degradation and extracellular fungal enzyme activities

Pentoses and hexoses were removed simultaneously from lucerne (Medicago sativa) stem by Piromonas communis and Neocallimastix frontalis growing axenically or in coculture with Methanobrevibacter smithii. In monocultures, more arabinose (68–71%) than glucose (52–53%) or xylose (25–30%) was removed. In cocultures, xylose solubilization from cell walls increased for P. communis whereas glucose solubilization increased for both fungi. The rates of sugar removal were monosaccharide-dependent. For both fungi, the specific activities of extracellular hydrolytic enzymes were markedly elevated in methanogenic cocultures.

Identification of an Antigenic Determinant on Anionic Peanut Peroxidase by Monoclonal Antibodies

Two monoclonal antibodies (46-12-C12 and 23-6-C12) raised against anionic peanut peroxidase were found to have independent epitope sites. These topographic sites were found to be located within a tryptic glycopeptide (Atgp) from the anionic isozyme by both indirect and non-competive ELISA and Western blotting. The Atgp has a Mr equal to 11 000 of which 70% is carbohydrate and the peptide is probably highly hydrophobic as determined by its high RF (0-83) value and the amino acid composition. McAb 23-6-C12 recognized a contiguous epitope which encompassed also the sole N-linked oligosaccharide on the anionic isozyme. That the monoclonal antibody also recognized the oligosaccharide on the «-amylase, /3-glucosidase, acid phosphatase, and horse-radish peroxidase may be related to similarities in sugars. Sugar removal from the Atgp or from the cross-reactive peptide of enzymes caused loss of antibody affinity. The monoclonal antibody 46-12-C12 recognized specifically a conformational epitope near the region of the cysteine, tryptophane and methionine residue on Atgp. Digestion of the anionic isozyme by trypsin resulted in a 40-fold loss of affinity with this monoclonal antibody. Moreover, treatment of the Atgp with performic acid or trifluoromethane sulphonic acid caused a loss of affinity between the treated Atgp and this monoclonal antibody.

A human monoclonal antibody against the CD4-binding site of HIV1 gp120 exhibits potent, broadly neutralizing activity

A human monoclonal antibody (HuMAb) against HIV1, 1125H, was isolated from an asymptomatic, seropositive haemophiliac. This antibody was specific for gp 120, and its binding to gp 120 was inhibited by soluble CD4, indicating that its epitope was in or near the CD4-binding site. 1125H antibody recognized a variety of divergent HIV1 strains, including most laboratory strains tested as well as some early passage isolates. Commensurate with its specificity and high apparent affinity, 1125H exhibited potent neutralizing activity against IIIB, MN, RF and SF-2 strains. The epitope recognized by 1125H was destroyed by reduction of disulphide bonds, but not by removal of N-linked sugars. Thus, the epitope was conformationally determined and did not involve carbohydrate. Data from radioimmunoprecipitation/SDS-PAGE analysis of proteolytically cleaved viral lysate further indicated that the epitope of 1125H was not affected by cleavage at the V3 loop of gp 120, provided that gp 120 disulphide bonds remained intact. The potential use of HuMAb 1125H in passive immunotherapy against HIV is discussed as well as the importance of including its epitope in an AIDS vaccine.

The role of carbohydrate in recombinant human erythropoietin

1. Recombinant human erythropoietin has N-linked sugar [Tsuda et al., (1988) Biochemistry 27, 5646-5654]. Here we have demonstrated the presence of O-linked sugar (0.85 mol/mol erythropoietin) composed of sialic acid and Gal beta(1-3)GalNAc. 2. To investigate the role of these sugars, erythropoietins deglycosylated to different extents were prepared using specific glycosidases. Sugars are not essential for in vitro biological activity of erythropoietin, because the fully deglycosylated erythropoietin had the full activity when assayed with in vitro bioassay methods. Asialylation yielded erythropoietin with higher affinity to the receptor than the undigested hormone and therefore an increased in vitro activity. Although erythropoietin from which N-linked or total sugars were removed also had higher affinity for the receptor, their in vitro activity remained unchanged compared with that of the undigested erythropoietin for unknown reasons. On the other hand, removal of sialic acids or N-linked sugar abolished the in vivo biological activity completely, indicating that the presence of N-linked sugar with terminal sialic acids is required for the hormone to reach target sites; full deglycosylation resulted in total loss of the in vivo biological activity of erythropoietin. 3. Incubation of asialo-erythropoietin and fully deglycosylated recombinant human erythropoietin at 70 degrees C for 15 min decreased the biological activity to 35% and 11% of the initial activity, respectively, while the undigested erythropoietin lost no activity. Thus resistance of erythropoietin to thermal inactivation is largely due to the presence of sugars, and terminal sialic acids greatly contribute to the stability.

Isolation and characterization of 5T4, a tumour‐associated antigen

The monoclonal antibody (MAb) 5T4 defines a human trophoblast antigen marker with a restricted pattern of expression in normal adult tissues but this antigen is expressed on a variety of carcinomas. The purification of 5T4 antigenic molecules is described from term syncytiotrophoblast by a combination of lectin- and immunoaffinity chromatography and gel filtration giving up to 10,000-fold purification with 70% yield. The antigen is carried by non-associated glycoprotein molecules with an apparent molecular weight of 72 kDa on SDS-PAGE and a neutral pI. Removal of N-linked sugars by N-glycanase reveals a core protein of 42 kDa. Treatment with enzymes that cleave O-linked sugars does not substantially alter the molecular size. The native 5T4 molecules are very resistant to proteolysis until the N-linked sugars are removed or the glycoprotein is denatured and reduced. Glycopeptides generated by these approaches will be suitable for amino acid sequencing.

Method for the determination of residues of the herbicide glyphosate and its principal metabolite, aminomethylphosphonic acid, in plant materials by nitrogen-selective gas chromatography

A method has been developed for the determination of residues of glyphosate and its major metabolite, aminomethylphosphonic acid, in stem tissues of blueberries and raspberries. This method involves extraction with water, removal of pigments by charcoal treatment followed by column chromatography using a cation-exchange resin for removal of sugar, a single-step derivatization reaction, and quantification by gas chromatography with a nitrogen-phosphorus detector. Limits of detection for glyphosate and its metabolite were 0.03 and 0.01 mg kg −1, respectively, for both blueberry and raspberry stems.

P-glycoproteins encoded by mdr 1b in murine gravid uterus and multidrug resistant tumor cell lines are differentially glycosylated

There are 3 members of the multidrug-resitance gene family expressed in mouse. Only one of these, mdr lb, and its gene product P-glycoprotein are induced to high levels in the mouse endometrium during pregnancy. It is shown here that P-glycoprotein in the gravid uterus is significantly larger ( M r 155000) compared to P-glycoprotein encoded by mdr lb in a murine multidrug-resistant cell line ( M r 140000). However, both species co-migrate after enzymatic removal of N-linked sugars ( M r 125000). These results demonstrate that differential glycosylation of the mdr lb gene product contributes to molecular heterogeneity found in P-glycoprotein from normal and multidrug-resistant cells.