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PubMed1986

The dietary intake of added and natural sugars in 405 English adolescents.

A number of reports have urged a reduction in sugars intake. Implementing this advice depends upon knowledge of sugars intake by target groups. This paper reports the added and natural sugars intake by one target group--young adolescents. The diet of 405 children was recorded using a 3-day diary with interview repeated five times between September 1979 and July 1981. Food tables (Paul & Southgate, 1978) were used and the values for the sugars content of the food items altered to provide both added sugars and natural sugars concentration. The mean daily intake of added and natural sugars respectively, for the 193 boys was 85 g (s.d. 22), 39 g (s.d. 12), and for the 212 girls was 78 g (s.d. 24), 35 g (s.d. 12). Added sugars contributed, on average, 69 per cent of total sugars and 15 per cent of energy intake. Confectionery, table sugar and soft drinks together contained 71 per cent of the added sugars intake, while milk, fruit and their products provided the majority of the natural sugars. It is considered that major reductions of sugars intake would be possible in these children by restricting the intake of a small number of groups of foods of low nutrient density. Food labelling of sugars content would enable consumers to make sensible choices of foods.

Adolescent↗

PubMed1990

Estimation of elution times on reverse-phase high-performance liquid chromatography of pyridylamino derivatives of sugar chains from glycoproteins.

Addition of a sugar residue to a pyridylamino (PA) sugar chain affects its elution time on reverse-phase HPLC and the contribution of the sugar residue is not influenced by the other sugar residues [S. Hase, S. Natsuka, H. Oku, and T. Ikenaka (1987) Anal. Biochem. 167, 321-326]. The partial relative elution times (Ei) of 22 sugar residues were calculated from the relative elution times (the elution time relative to Man5Glc-NAc2-PA) of three kinds of PA-sugar chain: the oligomannose and N-acetyllactosamine types and sugar chains with a xylose residue. The relative elution time of a PA-sugar chain can be calculated by summing the Ei values of all of the constituent sugar residues. The calculated relative elution times of 44 PA-sugar chains agreed well with the observed values. This method can be used to estimate the relative elution times of PA-sugar chains that are not yet available, and to estimate the structures of sugar chains in limited amounts of glycoproteins by a combination of sugar composition analysis and exoglycosidase digestion.

Aminopyridines↗

PubMedDate not supplied

Sugar-dependent rats show enhanced intake of unsweetened ethanol.

Rats show signs of dependence on sugar when it is available intermittently, including bingeing, withdrawal, and cross-sensitization with amphetamine. In the current study, we sought to determine whether sugar-dependent rats would show increased intake of unsweetened ethanol and, conversely, whether intermittent access to ethanol would augment sugar consumption. In Experiment 1, with intermittent versus ad libitum access to ethanol, Sprague-Dawley rats were given escalating concentrations of ethanol (1%, 2%, 4%, 7%, and 9%) over the course of 20 days. Rats in the intermittent ethanol access group, with 12-h daily access, consumed more 4%, 7%, and 9% ethanol during the first hour of access, and more 9% ethanol daily, than did rats in the ad libitum ethanol access group. In Experiment 2, with ethanol as a gateway to sugar intake, the rats from Experiment 1 were switched to 10% sucrose with 12-h daily access for 1 week. Rats in the intermittent ethanol access group consumed significantly more sugar than was consumed by rats in a control group with no prior ethanol experience. In Experiment 3, with sugar as a gateway to ethanol to determine whether sugar dependence leads to increased ethanol intake, four groups were maintained for 21 days according to the following designations: intermittent access to sugar and chow, ad libitum access to sugar and chow, intermittent access to chow, or ad libitum access to chow. Four days later, all groups were switched to intermittent ethanol access, as described in Experiment 1. The group with intermittent access to sugar and chow consumed the most 9% ethanol, supporting the suggestion that sugar dependence alters a rat's proclivity to drink ethanol. These results may relate to the co-morbidity between binge-eating disorders and alcohol intake and the tendency of people abstaining from alcohol to consume excessive amounts of sugar. In conclusion, bingeing on either ethanol or sugar fosters intake of the other.

Alcohol Drinking↗

PubMed2006

Sugars as tobacco ingredient: Effects on mainstream smoke composition.

Sugars are natural tobacco components, and are also frequently added to tobacco during the manufacturing process. This review describes the fate of sugars during tobacco smoking, in particular the effect of tobacco sugars on mainstream smoke composition. In natural tobacco, sugars can be present in levels up to 20 wt%. In addition, various sugars are added in tobacco manufacturing in amounts up to 4 wt% per sugar. The added sugars are usually reported to serve as flavour/casing and humectant. However, sugars also promote tobacco smoking, because they generate acids that neutralize the harsh taste and throat impact of tobacco smoke. Moreover, the sweet taste and the agreeable smell of caramelized sugar flavors are appreciated in particular by starting adolescent smokers. Finally, sugars generate acetaldehyde, which has addictive properties and acts synergistically with nicotine in rodents. Apart from these consumption-enhancing pyrolysis products, many toxic (including carcinogenic) smoke compounds are generated from sugars. In particular, sugars increase the level of formaldehyde, acetaldehyde, acetone, acrolein, and 2-furfural in tobacco smoke. It is concluded that sugars in tobacco significantly contribute to the adverse health effects of tobacco smoking.

Acetaldehyde↗

PubMed1991

Inhibitions of sugar transport produced by ligands binding at opposite sides of the membrane. Evidence for simultaneous occupation of the carrier by maltose and cytochalasin B.

This study examines inhibitions of human erythrocyte D-glucose uptake at ice temperature produced by maltose and cytochalasin B. Maltose inhibits sugar uptake by binding at or close to the sugar influx site. Maltose is thus a competitive inhibitor of sugar uptake. Cytochalasin B inhibits sugar transport by binding at or close to the sugar efflux site and thus acts as a noncompetitive inhibitor of sugar uptake. When maltose is present in the uptake medium, Ki(app) for cytochalasin B inhibition of sugar uptake increases in a hyperbolic manner with increasing maltose. When cytochalasin B is present in the uptake medium, Ki(app) for maltose inhibition of sugar uptake increases in a hyperbolic manner with increasing cytochalasin B. High concentrations of cytochalasin B do not reverse the competitive inhibition of D-glucose uptake by maltose. These data demonstrate that maltose and cytochalasin B binding sites coexist within the glucose transporter. These results are inconsistent with the simple, alternating conformer carrier model in which maltose and cytochalasin B binding sites correspond to sugar influx and sugar efflux sites, respectively. The data are also incompatible with a modified alternating conformer carrier model in which the cytochalasin B binding site overlaps with but does not correspond to the sugar efflux site. We show that a glucose transport mechanism in which sugar influx and sugar efflux sites exist simultaneously is consistent with these observations.

Binding Sites↗

PubMed2003

The scientific basis of recent US guidance on sugars intake.

Most fruits and dairy products are high in sugars, and thus naturally occurring sugars are consumed as part of a healthy diet. Sugars are also added to foods during processing or preparation, primarily to enhance taste. Monosaccharides and disaccharides added to foods are chemically indistinguishable from naturally occurring forms. However, concern has been expressed about the apparent increasing consumption of added sugars and their possible role in displacing or diluting nutrients in the diet and contributing to the epidemic of obesity in developed countries. One of the 2000 Dietary Guidelines for Americans states, "Choose beverages and foods to moderate your intake of sugars." The Dietary Guidelines Advisory Committee discussed whether to specify added sugars rather than the broader term sugars but decided that it was not possible to conclude that added sugars per se play a negative role in the public's health. The Dietary Guidelines Advisory Committee issued a call for more definitive studies of the role of sugars in current diets and the potential effect of a reduction in added sugars on both dietary quality and energy intake. The American Heart Association recently released a statement advising consumers to limit sugars consumption. The macronutrient report for the dietary reference intakes addresses many of these same issues; the expert panel concluded that it was not appropriate to set a tolerable upper intake level for added sugars but suggested a maximal intake level of 25% of energy from added sugars because of concerns about reduced intakes of essential micronutrients.

Adolescent↗

PubMed2003

Characterization of mutants in Arabidopsis showing increased sugar-specific gene expression, growth, and developmental responses.

Sugars such as sucrose serve dual functions as transported carbohydrates in vascular plants and as signal molecules that regulate gene expression and plant development. Sugar-mediated signals indicate carbohydrate availability and regulate metabolism by co-coordinating sugar production and mobilization with sugar usage and storage. Analysis of mutants with altered responses to sucrose and glucose has shown that signaling pathways mediated by sugars and abscisic acid interact to regulate seedling development and gene expression. Using a novel screen for sugar-response mutants based on the activity of a luciferase reporter gene under the control of the sugar-inducible promoter of the ApL3 gene, we have isolated high sugar-response (hsr) mutants that exhibit elevated luciferase activity and ApL3 expression in response to low sugar concentrations. Our characterization of these hsr mutants suggests that they affect the regulation of sugar-induced and sugar-repressed processes controlling gene expression, growth, and development in Arabidopsis. In contrast to some other sugar-response mutants, they do not exhibit altered responses to ethylene or abscisic acid, suggesting that the hsr mutants may have a specifically increased sensitivity to sugars. Further characterization of the hsr mutants will lead to greater understanding of regulatory pathways involved in metabolite signaling.

Abscisic Acid↗

PubMed2006

Interaction between rice MYBGA and the gibberellin response element controls tissue-specific sugar sensitivity of alpha-amylase genes.

Expression of alpha-amylase genes during cereal grain germination and seedling growth is regulated negatively by sugar in embryos and positively by gibberellin (GA) in endosperm through the sugar response complex (SRC) and the GA response complex (GARC), respectively. We analyzed two alpha-amylase promoters, alphaAmy3 containing only SRC and alphaAmy8 containing overlapped SRC and GARC. alphaAmy3 was sugar-sensitive but GA-nonresponsive in both rice (Oryza sativa) embryos and endosperms, whereas alphaAmy8 was sugar-sensitive in embryos and GA-responsive in endosperms. Mutation of the GA response element (GARE) in the alphaAmy8 promoter impaired its GA response but enhanced sugar sensitivity, and insertion of GARE in the alphaAmy3 promoter rendered it GA-responsive but sugar-insensitive in endosperms. Expression of the GARE-interacting transcription factor MYBGA was induced by GA in endosperms, correlating with the endosperm-specific alphaAmy8 GA response. alphaAmy8 became sugar-sensitive in MYBGA knockout mutant endosperms, suggesting that the MYBGA-GARE interaction overrides the sugar sensitivity of alphaAmy8. In embryos overexpressing MYBGA, alphaAmy8 became sugar-insensitive, indicating that MYBGA affects sugar repression. alpha-Amylase promoters active in endosperms contain GARE, whereas those active in embryos may or may not contain GARE, confirming that the GARE and GA-induced MYBGA interaction prevents sugar feedback repression of endosperm alpha-amylase genes. We demonstrate that the MYBGA-GARE interaction affects sugar feedback control in balanced energy production during seedling growth and provide insight into the control mechanisms of tissue-specific regulation of alpha-amylase expression by sugar and GA signaling interference.

Gene Expression Regulation, Plant↗

PubMed1994

Chemostat cultivation as a tool for studies on sugar transport in yeasts.

Chemostat cultivation enables investigations into the effects of individual environmental parameters on sugar transport in yeasts. Various means are available to manipulate the specific rate of sugar uptake (qs) in sugar-limited chemostat cultures. A straightforward way to manipulate qs is variation of the dilution rate, which, in substrate-limited chemostat cultures, is equal to the specific growth rate. Alternatively, qs can be varied independently of the growth rate by mixed-substrate cultivation or by variation of the biomass yield on sugar. The latter can be achieved, for example, by addition of nonmetabolizable weak acids to the growth medium or by variation of the oxygen supply. Such controlled manipulation of metabolic fluxes cannot be achieved in batch cultures, in which various parameters that are essential for the kinetics of sugar transport cannot be controlled. In sugar-limited chemostat cultures, yeasts adapt their sugar transport systems to cope with the low residual sugar concentrations, which are often in the micromolar range. Under the conditions, yeasts with high-affinity proton symport carriers have a competitive advantage over yeasts that transport sugars via facilitated-diffusion carriers. Chemostat cultivation offers unique possibilities to study the energetic consequences of sugar transport in growing cells. For example, anaerobic, sugar-limited chemostat cultivation has been used to quantify the energy requirement for maltose-proton symport in Saccharomyces cerevisiae. Controlled variation of growth conditions in chemostat cultures can be used to study the differential expression of genes involved in sugar transport and as such can make an important contribution to the ongoing studies on the molecular biology of sugar transport in yeasts.

Biological Transport↗

PubMed2003

Structure-function relationships affecting the insecticidal and miticidal activity of sugar esters.

Synthetic sugar esters are a relatively new class of insecticidal compounds that are produced by reacting sugars with fatty acids. The objective of this research was to determine how systematic alterations in sugar or fatty acid components of sugar ester compounds influenced their insecticidal properties. Sucrose octanoate, sorbitol octanoate, sorbitol decanoate, sorbitol caproate, xylitol octanoate, xylitol decanoate and xylitol dodecanoate were synthesized and evaluated against a range of arthropod pests. Dosage-mortality studies were conducted on pear psylla (Cacopsylla pyricola Foerster) on pear, tobacco aphid (Myzus nicotianae) Blackman and tobacco hornworm (Manduca sexta [Johannson]) on tobacco, and twospotted spider mite (Tetranychus urticae Koch) on apple in laboratory bioassays. These sugar esters were compared with insecticidal soap (M-Pede, Dow AgroSciences L.L.C., San Diego, CA), to determine how toxicologically similar these materials were against the arthropod pests. Substitutions in either the sugar or fatty acid component led to significant changes in the physical properties and insecticidal activity of these compounds. The sugar esters varied in their solubility in water and in emulsion stability, yet, droplet spread upon pear leaves occurred at low concentrations of 80-160 ppm and was strongly correlated with psylla mortalities (R2 = 0.73). Sequentially altering the sugar or fatty acid components from lower to higher numbers of carbon chains, or whether the sugar was a monosaccharide or disaccharide did not follow a predictable relationship to insecticidal activity. Intuitively, changing the hydrophile from sorbitol (C6) to xylitol (C5) would require a decrease in lipophile chain length to maintain hydrophilic-lipophilic balance (HLB) relationships, yet an increase in lipophile chain length was unexpectedly needed for increasing insecticidal activity. Thus, the HLB of these materials did not correlate with pear psylla mortalities. Initial insect bioassays and dosage-mortality data found significant differences among sugar ester compounds' toxicity to the range of arthropod species. Sucrose octanoate high in monoester content had the highest activity against the range of arthropod pests at low concentrations of 1200-2400 ppm. No single chemical structure for the xylitol or sorbitol esters were optimally effective against the range of arthropods we tested and sorbitol octanoate and xylitol decanoate had the highest insecticidal activity of this group. All of the sugar ester materials produced high T. urticae mortalities on apple at very low concentrations of 400 ppm. Overall, most of the sugar esters that were examined had superior insecticidal activity compared with insecticidal soap. Sugar ester chemistry offers a unique opportunity to design an insecticide or miticide specific to certain arthropod pests which would be valuable in crop integrated pest management (IPM) programs. Sucrose esters are currently used as additives in the food industry which makes them especially attractive as safe and effective insecticides.

Animals↗

PubMed1984

Substrate properties of 5-fluorouridine diphospho sugars detected in hepatoma cells.

Nucleotide sugars derived from 5-fluorouridine were studied in cultured AS-30D hepatoma cells as well as in kinetic enzyme assays in vitro in comparison with the physiologic uridine diphospho sugars. Hepatoma cells converted 5-fluoro [14C]uridine to 5-fluorouridine diphospho (FUDP) glucose, FUDP-galactose, FUDP-N-acetylglucosamine, FUDP-N-acetylgalactosamine, and trace amounts of FUDP-glucuronate, as analyzed by different systems of high-performance liquid chromatography. 5-Fluoro[14C]uridine and [14C]uridine, at concentrations of 5 microM in the culture medium, were phosphorylated by the cells during 60 min to similar amounts of FUTP and UTP, respectively, while the synthesis of [14]FUDP-sugars was reduced to 14% as compared to that of [14C]UDP-sugars. FUDP-sugars, synthesized by chemical and enzymatic procedures, were assayed in vitro as substrates for enzymes of UDP-sugar metabolism. Km and V values in a range comparable to that of the respective UDP-sugars were determined for FUDP-sugars in the reactions catalyzed by UDP-glucose pyrophosphorylase, galactose-1-phosphate uridylyltransferase, UDP-glucose 4-epimerase, UDP-N-acetylglucosamine 2-epimerase, glycogen synthase, and UDP-glucose dehydrogenase. Our experiments in hepatoma cells and with enzymes in vitro have revealed additional reactions of FUDP-sugar metabolism demonstrating a metabolite pattern analogous to that of UDP-sugars. The amounts of FUDP-sugars formed relative to UDP-sugars in intact cells were smaller than suggested on the basis of their kinetic comparison in vitro.

Animals↗

PubMed2003

Fat-sugar see-saw in school lunches: impact of a low fat intervention.

PURPOSE: To determine the long-term effects of a low fat intervention on sugar content in school lunches METHODS: We calculated contributions of total sugars, 6 specific sugars, and selected nutrients in National School Lunch Program meals served in 56 former intervention, 20 randomly selected control schools that had participated 3 years before in a low fat intervention, and 12 additional schools from neighboring school districts that had never been exposed to the intervention, whose goal was the lowering of total fat to under 30% of calories and saturated fat to under 10% calories. Analysis of variance adjusted for region was used to compare treatment groups. Pearson partial correlations controlling for the effects of region and treatment group were used to assess the strength of sugar and fat relationships. RESULTS: Three years after the low fat intervention, former intervention, control and unexposed schools lunches were similar in mean total sugars (25% of calories), and "added" sugars (e.g. sucrose, glucose, galactose, and maltose) at 15% of calories; and differed only in their lactose content. As percent of calories from fat or saturated fat in lunches decreased, that from sugars increased. Lunches that met reduced saturated fat goals were significantly higher than those not meeting goals in percent of calories from sugars both in meals as offered (27.6 +/- 0.3% vs. 26.2 +/- 0.3 SE p =.004) and as served (26.5 +/- 0.4 vs. 23.9 +/- 0.4 p =.009). Lunches meeting reduced total fat goals were significantly higher only in percent of calories from sugars as served. Seventy-five percent of total sugar in lunches offered was from chocolate milk, fruit/fruit juices, and white milk. More "added" sugar came from high micronutrient foods, such as fruit, fruit juices, and chocolate milk than from desserts and entrees. CONCLUSIONS: The existence of a fat-sugar "see-saw" makes it important to emphasize substitutions of fat and saturated fat with starches and fiber in school lunches.

Adolescent↗

PubMed2005

Quench-flow analysis reveals multiple phases of GluT1-mediated sugar transport.

Standard models for carrier-mediated nonelectrolyte transport across cell membranes do not explain sugar uptake by human red blood cells. This means that either (1) the models for sugar transport are incorrect or (2) measurements of sugar transport are flawed. Most measurements of red cell sugar transport have been made over intervals of 10 s or greater, a range which may be too long to measure transport accurately. In the present study, we examine the time course of sugar uptake over intervals as short as 5 ms to periods as long as 8 h. Using conditions where transport by a uniform population of cells is expected to be monophasic (use of subsaturating concentrations of a nonmetabolizable but transported sugar, 3-O-methylglucose), our studies demonstrate that red cell sugar uptake is comprised of three sequential, protein-mediated events (rapid, fast, and slow). The rapid phase is more strongly temperature-dependent than the fast and slow phases. All three phases are inhibited by extracellular (maltose or phloretin) or intracellular (cytochalasin B) sugar-transport inhibitors. The rate constant for the rapid phase of uptake is independent of the 3-O-methylglucose concentration. The magnitude (moles of sugar associated with cells) of the rapid phase increases in a saturable manner with [3-O-methylglucose] and is similar to (1) the amount of sugar that is retained by red cell membrane proteins upon addition of cytochalasin B and phloretin and (2) the d-glucose inhibitable cytochalasin B binding capacity of red cell membranes. These results are consistent with the hypothesis that previous studies have both under- and overestimated the rate of erythrocyte sugar transport. These data support a transport mechanism in which newly bound sugars are transiently sequestered within the translocation pathway where they become inaccessible to extra- and intracellular water.

3-O-Methylglucose↗

PubMed1999

Stop-flow analysis of cooperative interactions between GLUT1 sugar import and export sites.

The human erythrocyte sugar transporter is thought to function either as a simple carrier (sugar import and sugar export sites are presented sequentially) or as a fixed-site carrier (sugar import and sugar export sites are presented simultaneously). The present study examines each hypothesis by analysis of the rapid kinetics of reversible cytochalasin B binding to the sugar export site in the presence and absence of sugars that bind to the sugar import site. Cytochalasin B binding to the purified, human erythrocyte glucose transport protein (GLUT1) induces quenching of GLUT1 intrinsic tryptophan fluorescence. The time-course of GLUT1 fluorescence quenching reflects a second-order process characterized by simple exponential kinetics. The pseudo-first-order rate constant describing fluorescence decay (kobs) increases linearly with [cytochalasin B] while the extent of fluorescence quenching increases in a saturable manner with [cytochalasin B]. Rate constants for cytochalasin B binding to GLUT1 (k1) and dissociation from the GLUT1.cytochalasin B complex (k-1) are obtained from the relationship: kobs = k-1 + k1[cytochalasin B]. Low concentrations of maltose, D-glucose, 3-O-methylglucose, and other GLUT1 import-site reactive sugars increase k-1(app) and reduce k1(app) for cytochalasin B interaction with GLUT1. Higher sugar concentrations decrease k1(app) further. The simple carrier mechanism predicts that k1(app) alone is modulated by import- and export-site reactive sugars and is thus incompatible with these findings. These results are consistent with a fixed-site carrier mechanism in which GLUT1 simultaneously presents cooperative sugar import and export sites.

3-O-Methylglucose↗

PubMed2006

Self-reported sugar-sweetened beverage intake among college students.

OBJECTIVE: To characterize sugar-sweetened beverage intake of college students. RESEARCH METHODS AND PROCEDURES: Undergraduates in an urban southern community campus were surveyed anonymously about sugared beverage consumption (soda, fruit drinks, energy drinks, sports drinks, sweet ice tea) in the past month. RESULTS: Two hundred sixty-five undergraduates responded (66% women, 46% minority, 100% of volunteers solicited). Most students (95%) reported sugared beverage intake in the past month, and 65% reported daily intake. Men were more likely than women to report daily intake (74% vs. 61%, p = 0.035). Soda was the most common sugar-sweetened beverage. Black undergraduates reported higher sugared beverage intake than whites (p = 0.02), with 91% of blacks reporting sugar-sweetened fruit drink intake in the past month and 50% reporting daily consumption. Mean estimated caloric intake from combined types of sugar-sweetened beverages was significantly higher among black students than whites, 796 +/- 941 vs. 397 +/- 396 kcal/d (p = 0.0003); the primary source of sugar-sweetened beverage calories among blacks was sugared fruit drinks (556 +/- 918 kcal/d). Younger undergraduates reported significantly higher intake than older students (p = 0.025). DISCUSSION: Self-reported sugar-sweetened beverage consumption among undergraduates is substantial and likely contributes considerable non-nutritive calories, which may contribute to weight gain. Black undergraduates may be particularly vulnerable due to higher sugared beverage intake. Obesity prevention interventions targeting reductions in sugar-sweetened beverages in this population merit consideration.

Adult↗

PubMed2005

Micronutrient dilution associated with added sugar intake in elderly black South African women.

OBJECTIVES: To investigate the association between added sugar and macronutrient and micronutrient intakes, and to assess whether added sugar intake is related to biochemical indices of nutritional status, Mini-Nutritional Assessment (MNA) score, body mass index (BMI) and performance on physical function tests. DESIGN: A cross-sectional, analytical study. SETTING AND SUBJECTS: Convenient sample of 285 institutionalised and community-dwelling black South African men and women aged 60+ y. METHODS: An interviewer-administered 24-h dietary recall and MNA were performed. Serum albumin, vitamin B12, ferritin, cholesterol, haemoglobin, red blood cell (RBC) folate and plasma vitamin C were measured. Handgrip strength, BMI, 'sit-to-stand' and 'get-up-and-go' tests were measured. Outcome variables were analysed according to tertiles of added sugar, in grams and as a percentage of total energy (% E). RESULTS: In each tertile of sugar intake, mean MNA score fell in the 'at-risk' classification. In women, energy, protein, % E protein, fibre, thiamin, riboflavin, niacin, vitamin B6, folate, pantothenic acid, biotin, vitamin C, calcium, iron, magnesium, phosphorus, zinc, copper and selenium intake were significantly lowest in subjects in the highest % E sugar tertile. In men, no differences were found for micronutrient intake according to tertiles of total added sugar or % E added sugar. Physical function declined with increasing sugar intake, and suboptimal RBC folate and plasma ascorbic acid status was associated with increasing sugar intake (in women). No relationship was found between added sugar intake and the very high prevalence (65%) of obesity in women. CONCLUSION: A nutrient-diluting effect of added sugars intake was demonstrated in elderly black South African women. Further studies in this population are required in order to develop food-based dietary guidelines, which include messages on added sugar intake.

Activities of Daily Living↗

PubMed2000

Remodeling of sugar chain structures of human interferon-gamma.

Natural human interferon (IFN)-gamma has mainly biantennary complex-type sugar chains and scarcely has multiantennary structures. We attempted to remodel the sugar chain structures using IFN-gamma as a model glycoprotein. To obtain the branching glycoforms of IFN-gamma, we introduced the genes for GnT-IV (UDP-N-acetylglucosamine:alpha-1,3-D-mannoside beta-1, 4-N-acetylglucosaminyltransferase) and/or GnT-V (UDP-N-acetylglucosamine:alpha-1,6-D-mannoside beta-1, 6-N-acetylglucosaminyltransferase) into Chinese hamster ovary (CHO) cells producing human IFN-gamma. The parental CHO cells produced IFN-gamma with biantennary sugar chains mainly. When the GnT-IV activity was increased, triantennary sugar chains with a branch produced by GnT-IV increased up to 66.9% of the total sugar chains. When the GnT-V activity was increased, triantennary sugar chains with a corresponding branch increased up to 55.7% of the total sugar chains. When the GnT-IV and -V activities were increased at a time, tetraantennary sugar chains increased up to 56.2% of the total sugar chains. The proportion of these multiantennary sugar chains corresponded to the intracellular activities of GnT-IV and -V. What is more, lectin blot and flow cytometric analysis indicated that the multi-branch structure of the sugar chains was increased not only on IFN-gamma, one of the secretory glycoproteins, but also on almost CHO cellular proteins by introducing either or both of the GnT genes. The results suggest that the branching structure of sugar chains of glycoproteins could be controlled by cellular GnT-IV and GnT-V activities. This technology can produce glycoforms out of natural occurrence, which should enlarge the potency of glycoprotein therapeutics.

Animals↗

PubMed2003

Water relations link carbon and oxygen isotope discrimination to phloem sap sugar concentration in Eucalyptus globulus.

A strong correlation was previously observed between carbon isotope discrimination (Delta(13)C) of phloem sap sugars and phloem sap sugar concentration in the phloem-bleeding tree Eucalyptus globulus Labill. (J. Pate, E. Shedley, D. Arthur, M. Adams [1998] Oecologia 117: 312-322). We hypothesized that correspondence between these two parameters results from covarying responses to plant water potential. We expected Delta(13)C to decrease with decreasing plant water potential and phloem sap sugar concentration to increase, thereby maintaining turgor within sieve tubes. The hypothesis was tested with analyses of E. globulus trees growing on opposite ends of a rainfall gradient in southwestern Australia. The Delta(13)C of phloem sap sugars was closely related to phloem sap sugar concentration (r = -0.90, P < 0.0001, n = 40). As predicted, daytime shoot water potential was positively related to Delta(13)C (r = 0.70, P < 0.0001, n = 40) and negatively related to phloem sap sugar concentration (r = -0.86, P < 0.0001, n = 40). Additional measurements showed a strong correspondence between predawn shoot water potential and phloem sap sugar concentration measured at midday (r = -0.87, P < 0.0001, n = 30). The Delta(13)C of phloem sap sugars collected from the stem agreed well with that predicted from instantaneous measurements of the ratio of intercellular to ambient carbon dioxide concentrations on subtending donor leaves. In accordance, instantaneous ratio of intercellular to ambient carbon dioxide concentrations correlated negatively with phloem sap sugar concentration (r = -0.91, P < 0.0001, n = 27). Oxygen isotope enrichment (Delta(18)O) in phloem sap sugars also varied with phloem sap sugar concentration (r = 0.91, P < 0.0001, n = 39), consistent with predictions from a theoretical model of Delta(18)O. We conclude that drought induces correlated variation in the concentration of phloem sap sugars and their isotopic composition in E. globulus.

Carbohydrate Metabolism↗