Effects Of Various Carbohydrates Research Articles

Effect of Various Carbohydrates in Aqueous Solutions on Color Stability and Degradation Kinetics of Selected Anthocyanins During Storage.

Anthocyanins are flavonoid substances of plant origin with potential antioxidant effects. Because of their intense colors, they are used as natural dyes in food. However, their stability in food matrices is limited. This study aimed to verify the effect of selected carbohydrates on the stability of anthocyanins (cyanidin-3-O-β-glucopyranoside, cyanidin-3-O-β-galactopyranoside, cyanidin-3-O-β-rutinoside and delphinidin-3-O-β-rutinoside) during the accelerated storage test, since carbohydrates help to preserve the typical color of anthocyanins, increase their shelf-life and availability in the organism, and reduce losses during processing. Moreover, the kinetic parameters of anthocyanin degradation (Ea, k, t1/2) were determined. Sucrose was found to have the greatest potential for retarding anthocyanin degradation during storage, whereas fructose exerted an accelerating effect. Glycosidation of anthocyanin aglycone had no significant effect in terms of their stability. Anthocyanin degradation was significantly positively correlated with the change in the a* parameter (redness), and subsequently, a significant positive correlation was observed in the determination of the kinetic parameters for anthocyanins and the a* parameter. The highest stability of anthocyanins was observed in the presence of sucrose and their degradation can be predicted by the value of the a* parameter, which would also be a very fast and non-destructive method for food processing companies.

The Effects of Various Carbohydrates and Tannic Acid on the Food Consumption and Growth Performance of Uresiphita gilvata (Lepidoptera: Crambidae)

The effects of carbohydrates and tannen on the development and food preferences of Uresiphita gilvata larvae were investigated in this study. In addition, with the addition of tannin, the importance of plant-herbivore co-evolution in the food choice of the larvae was mentioned. For this reason, thirteen different artificial diets were prepared. Each diet contains sucrose, glucose, galactose, maltose, fructose, arabinose, mannose, or starch at the same concentration. To investigate the effect of tannic acid, 5 % tannic acid was added to the diets each containing sucrose, starch, glucose or maltose at the same concentration. According to the results of the study, sucrose was consumed by larvae more than glucose and fructose. However, the maximum food consumption of U. gilvata larvae was on the diet containing arabinose and their minimum consumption was on the diet containing mannose. Galactose is more consumed by larvae. However, intake galactose can not converted to pupal lipid by larvae. The addition of tannin to the diet reduced the amount of consumption of diet the dry pupal weight and lipid amount of pupae. However, the addition of tannin to the diet increased the amount of protein and extended the development time of pupae.

The role of dietary carbohydrates in organismal aging.

Carbohydrates are essential nutrients that are used as a primary source of energy. Carbohydrate utilization should be properly controlled, as abnormal regulation of carbohydrate metabolism is associated with diseases, such as diabetes, cardiovascular diseases, and stroke. These metabolic syndromes have become a serious problem in developed countries, and there is an increased need for research examining the influence of carbohydrates on animal physiology. Diets enriched in glucose, a major carbohydrate, are also associated with accelerated aging in several model organisms, including yeast and Caenorhabditis elegans (C. elegans). Genetic factors that mediate the effects of high glucose diets on aging have been identified during the last decade, mostly through the use of C. elegans. In this review, we describe studies that determine the effects of carbohydrate-enriched diets on aging by focusing on the mechanisms through which evolutionarily conserved pathways mediate the lifespan-altering effects of glucose in C. elegans. These include the insulin/insulin-like growth factor-1, sterol-regulatory element-binding protein, and AMP-activated protein kinase signaling pathways. We also discuss the effects of various carbohydrates and carbohydrate-derived metabolites on aging in model organisms and cultured mammalian cells. Finally, we discuss how dietary carbohydrates influence health and aging in humans.

Fermentable Carbohydrates Differentially Affect Colon Tumor Formation in Azoxymethane-Induced Male Fischer 344 Rats

Background: The role of fermentation compared with the source or type of the fermentable material in colon tumorigenesis remains an issue in refining the definition of dietary fiber (DF).Objective: The aim of this study was to investigate the fermentation and source-specific effects of various carbohydrates in a medium-term colon tumorigenesis model.Methods: Six-week-old male Fischer 344 rats were randomly allocated into 6 groups (n = 36/group) to receive either AIN-93G (control) or diets containing fructooligosaccharides, wheat bran (WB), oat bran (OB), polydextrose, or high-amylose maize starch (HAMS), each adjusted to contain a total DF concentration of 7% (wt:wt) and have a fermentability of 3% (wt:wt). After 2 wk, 24 rats/group received 2 subcutaneous doses of azoxymethane (at 15 mg/kg body weight) 1 wk apart while 12 rats/group were injected with a saline vehicle; all rats were maintained on the assigned diets for 24 wk postinjection and then killed. Colon tumor outcomes and pathology together with cecal short-chain fatty acid composition were assessed.Results: No tumors were found in saline-injected rats, and all subsequent analyses were restricted to azoxymethane-injected rats. Colon tumor incidence was significantly lower in the polydextrose (21%) and WB (13%) groups than in the control group (63%; P < 0.05) but not different from the fructooligosaccharide (58%), HAMS (46%), and OB (33%) groups. In comparison to the control group (8 proximal/31 total tumors), fermentable materials reduced the number of tumors (P < 0.05) originating in the proximal colon: HAMS (5/15), polydextrose (2/7), OB (2/9), fructooligosaccharides (1/21), and WB (1/3). The mean ± SEM number of tumors/tumor-bearing rats was significantly lower in the WB (1.00 ± 0.00), OB (1.13 ± 0.13), and HAMS (1.36 ± 0.15) groups than in the control group (2.07 ± 0.27; P < 0.02); other groups did not differ. The mean ± SEM tumor burden/diet group was lower in the WB (1.2 ± 0.7 mm2), polydextrose (6.7 ± 3.2 mm2), and OB (7.0 ± 3.0 mm2) groups than in the control (21.4 ± 5.9 mm2) and fructooligosaccharide (22.1 ± 7.1 mm2; P < 0.05) groups but not significantly different from the HAMS group (15.1 ± 6.1 mm2). Total cecal SCFA concentrations did not differ among diet groups (overall mean ± SEM: 81 ± 4 μmol/g wet weight).Conclusion: The rate and extent of fermentation of the carbohydrate material as well as the characteristics of the material in the lumen of the lower gastrointestinal tract all appear to have an important role in tumor outcomes in the azoxymethane-induced rat colon tumorigenesis assay.

Combined albumin and bicarbonate induces head-to-head sperm agglutination which physically prevents equine sperm-oviduct binding.

In many species, sperm binding to oviduct epithelium is believed to be an essential step in generating a highly fertile capacitated sperm population primed for fertilization. In several mammalian species, this interaction is based on carbohydrate-lectin recognition. D-galactose has previously been characterized as a key molecule that facilitates sperm-oviduct binding in the horse. We used oviduct explant and oviduct apical plasma membrane (APM) assays to investigate the effects of various carbohydrates; glycosaminoglycans; lectins; S-S reductants; and the capacitating factors albumin, Ca(2+) and HCO3(-) on sperm-oviduct binding in the horse. Carbohydrate-specific lectin staining indicated that N-acetylgalactosamine, N-acetylneuraminic acid (sialic acid) and D-mannose or D-glucose were the most abundant carbohydrates on equine oviduct epithelia, whereas D-galactose moieties were not detected. However, in a competitive binding assay, sperm-oviduct binding density was not influenced by any tested carbohydrates, glycosaminoglycans, lectins or D-penicillamine, nor did the glycosaminoglycans induce sperm tail-associated protein tyrosine phosphorylation. Furthermore, N-glycosidase F (PNGase) pretreatment of oviduct explants and APM did not alter sperm-oviduct binding density. By contrast, a combination of the sperm-capacitating factors albumin and HCO3(-) severely reduced (>10-fold) equine sperm-oviduct binding density by inducing rapid head-to-head agglutination, both of which events were independent of Ca(2+) and an elevated pH (7.9). Conversely, neither albumin and HCO3(-) nor any other capacitating factor could induce release of oviduct-bound sperm. In conclusion, a combination of albumin and HCO3(-) markedly induced sperm head-to-head agglutination which physically prevented stallion sperm to bind to oviduct epithelium.

Combining blood glucose testing with analysis of a classic paper in an endocrine physiology lab activity

Endocrine physiology lab activities can be challenging to do with limited resources, due to the complex nature of hormone regulation and the expense of measuring serum hormone levels. Simulated labs are available from various publishers, but hands‐on labs often require animal models, surgeries, and/or expensive reagents. In contrast, blood glucose testing requires relatively inexpensive equipment and can be performed in a 3‐hour lab period by students with little prior training in lab procedures. Consumption of different beverages (for example, water, orange juice, low‐sugar or high‐sugar nutritional shakes) followed by blood glucose testing at one or more time points allows students to see the effects of different amounts and types of carbohydrates on blood glucose levels. To extend this activity and illustrate the effects of various carbohydrates on insulin production, students read an article (Am. J. Physiol 1963;205:638‐644). This classic paper describes perfusion of isolated rat pancreas with various carbohydrates and measurement of insulin by radioimmunoassay (RIA). Students were asked to diagram the methods and interpret the data from the article. They also had to consider the evidence from the paper on effects of different sugars on insulin secretion when analyzing the class data on blood glucose levels over time after consuming various sugar combinations. Students were enthusiastic about the activity as a whole. The use of the classic paper helped to complete the conceptual framework of blood glucose homeostasis illustrated in part by blood glucose testing. In addition, students responded much more positively to this lab experience than to simulated labs on endocrine physiology offered in a previous semester.

An acetylation site in lectin domain modulates the biological activity of polypeptide GalNAc-transferase-2

Polypeptide GalNAc-transferases (ppGalNAc-Ts) are a family of enzymes that catalyze the initiation of mucin-type O-glycosylation. All ppGalNAc-T family members contain a common (QXW)3 motif, which is present in the R-type lectin group. The acetylation site K521 is part of the QKW motif of β-trefoil in the lectin domain of ppGalNAc-T2. We used a combination of acetylation and site-directed mutagenesis approaches to examine the functional role of K521 in ppGalNAc-T2. Binding assays of non-acetylated and acetylated forms of the mutant ppGalNAc-T2K521Q to various naked and αGalNAc-glycosylated mucin peptides indicated that the degree of interaction of lectin domain with αGalNAc depends on the peptide sequence of mucin. Studies of the inhibitory effect of various carbohydrates on the interactions of ppGalNAc-T2 with MUC1αGalNAc indicate that point K521Q mutation enhance the carbohydrate specificity of lectin domain for αGalNAc. K521Q mutation resulted in an enzyme activity lower than that of the wild-type ppGalNAc-T2, similar to the acetylation of ppGalNAc-T2. We conclude that an acetylation site in the QKW motif of the lectin domain modulates carbohydrate recognition specificity and catalytic activity of ppGalNAc-T2 for partially preglycosylated acceptors and a certain naked peptide. Posttranslational modifications of ppGalNAc-Ts, such as acetylation, may play key roles in modulating the functions of the R-type lectin domains in cellular homeostasis.

Hydroxyl distribution in sugar structure and its contributory role in the inhibition of Stachybotrys microspora β-glucosidase (bglG)

Stachybotrys microspora is a filamentous fungus that produces various β-glucosidases, of which two have already been characterized. The present study reports on the production of a third one, named bglG, in the presence of d-glucose used as a sole carbon source, and on its subsequent purification and characterization. Although efficiently produced in the presence of d-glucose, bglG continues to be highly inhibited by this sugar. In fact, the addition of d-glucose significantly decreases the glucose formation rates during the hydrolysis of pNPG. This work reports on the effect of various carbohydrates on bglG activity in order to understand the mechanisms adopted by d-glucose to inhibit this enzyme. The findings indicate that bglG is strongly inhibited by d-glucose (44% of the relative activity at 5mM), d-glucitol (96% of the relative activity), d-mannose (56% of the relative activity), cellobiose and maltose (72% and 71% of the relative activity, respectively). On the other hand, d-galactose, d-fructose, lactose, and sucrose have no effect on bglG activity. Similarly, several isomers, such as 2-acetamido-2-deoxy-d-glucose and 2-deoxy-d-arabino-hexose (2-deoxy-d-glucose) were noted to bring no change on the relative activity of bglG. d-xylose and xylitol, on the other hand, enhanced bglG activity up to 123% and 120% of relative activity, respectively. Accordingly, the configuration, epimerisation, isomerisation, and substitutions played key roles in bglG inhibition. The effect of the combination of iron (the best activator of bglG, 161%) with some of those additives was also investigated. The findings revealed that, while a combination of iron at a concentration of 10mM with d-glucose resulted in a two-fold decrease in bglG inhibition (84% at 5mM), iron maintained the same effect with the remainder of the additives being tested.

Effect of Carbohydrates on the Ability of Bull Sperm to Bind to Bovine Oviduct Epithelial Cells

In the present study, we investigated the effect of various carbohydrates on the ability of bovine spermatozoa to bind to the bovine oviduct epithelial cells (OECs). We also examined the fertilization competence and motility of spermatozoa that bind to OECs in the presence of carbohydrates. Frozen-thawed spermatozoa were incubated with OECs, with and without various carbohydrates. The sperms were then divided into two fractions: OEC-binding sperms (B-sperm) and non-OEC binding sperms (NB-sperm). The fertilization rate, ability to bind the zona pellucida, and membrane integrity of the spermatozoa as determined using a hypo-osmotic-swelling test (HOST) were lower in NB-sperm than in the unseparated spermatozoa (control). The motility of the B-sperm was maintained for a longer time than that of the control spermatozoa. The addition of N-acetyl-d-glucosamine (GlcNAc, 5 mm) to the sperm-OEC mixture increased the number of B-sperm. D-mannose (5 mm) and D-fucose (5 mm) had no effect on the number of B-sperm. The motility of B-sperm, which bound to OECs in the presence of GlcNAc, however, was not maintained. When either OECs or the spermatozoa were treated with GlcNAc prior to sperm-OEC co-incubation, only sperm-side treatment enhanced sperm-OEC binding, but B-sperm motility was not maintained. The motility of spermatozoa incubated with GlcNAc was lower than that of controls. These results indicate that GlcNAc enhances sperm binding to OECs, probably via sperm surface modification, but does not promote increased sperm survival.

Water‐Soluble Fluorescent Boronic Acid Compounds for Saccharide Sensing: Substituent Effects on Their Fluorescence Properties

Four new naphthalene-based boronic acid compounds (1-4) were synthesized. The effect of various carbohydrates on their fluorescence properties has been studied in aqueous phosphate buffer at pH 7.4. Different substitutions on the aniline group of the naphthalene ring resulted in significant differences in fluorescence properties for these four compounds. Compound 1 shows ratiometric fluorescence changes upon addition of a sugar. Compounds 2 and 3 do not show ratiometric fluorescence changes but show very large fluorescence intensity changes (about 70-fold fluorescence intensity increase). In addition to the quantifiable fluorescence property changes upon sugar addition, the fluorescence color changes of 1-3 are also visible to the naked eye. However, amidation of the aniline nitrogen atom significantly diminishes the fluorescence intensity of compound 4. The crystal structure of one boronic acid provided some insight into the structural features that are important for the fluorescence properties of these compounds.

Maturation and Conversion of Somatic Embryos of Three Genetically Diverse Rose Cultivars

Embryogenic callus cultures of three genetically diverse cultivars of rose (Rosa hybrida L.), the floribunda `Trumpeter', the multiflora `Dr. Huey', and the hybrid tea `Tineké', were used to study the effect of various carbohydrates and osmotically active compounds on somatic embryo maturation and conversion. Cotyledonary-stage embryos were produced by dispersing callus in liquid medium followed by filtration to isolate globular-stage embryos. Quantitative experiments were conducted to determine maturation and conversion of the three rose cultivars in response to medium with sucrose, glucose, fructose, or maltose as the primary carbon source and also in response to various concentrations of either myo-inositol, polyethylene glycol, or mannitol in combination with 3% sucrose. Conversion of 27% was achieved for `Trumpeter' embryos following their maturation on 3% fructose. `Dr. Huey' embryos required maturation on medium containing 3% sucrose supplemented with either 2.5% or 5% mannitol for 36% and 61% conversion, respectively. Maturation of `Tineké' embryos on either 3% sucrose, 3% glucose, or 3% fructose resulted in a maximum 12% conversion.

Selection of ergot alkaloid producers by induced mutagenesis

Using the induced mutagenesis technique, A series of genetically modified Claviceps sp. VKM F-2609 strains that display high levels of agroclavine and elymoclavine synthesis were selected by induced mutagenesis. Compared to the parent strain, c106 displayed a 40-fold higher level of agroclavine synthesis, and c66 displayed an eightfold higher level of elymoclavine synthesis. The levels of synthesis of other alkaloids were decreased in these strains. The effects of various carbohydrates on the strain growth and ergot alkaloid biosynthesis was then investigated in both the parent strain and c106. The largest amount of agroclavine was synthesized by c106 strain growing on a medium with maltose.

Osmotic Stress Induced by Carbohydrates Enhances Expression of Foreign Proteins in Escherichia coli

Arabinose has been serendipitously observed to enhance the expression of P450s in Escherichia coli. To understand the mechanism of this arabinose-dependent enhancement, the effects of various carbohydrates were investigated. Surprisingly, a series of sugars, including pentoses and hexoses, enhanced the foreign gene expression in a manner similar to arabinose. Furthermore, glycerol, a poor carbon source, also enhanced P450 expression. These results indicate that the enhancement is independent of the specific efficiency of the carbon source and also suggest the involvement of osmotic stress. Therefore, the effect of the ςs (also termed ς38) factor, a sigma subunit of RNA polymerase that plays a central role in regulating the expression of osmotic stress response genes, has been examined. We found that the glycerol-dependent increase in P450 expression was not observed in ςs-deficient E. coli, indicating that carbohydrates enhance the foreign gene expression in E. coli via the induction of the osmotic stress response. The results suggest the important role of the osmotic stress response in posttranscriptional processes required for producing functional proteins.

Inhibitory effects of carbohydrates on cholesterol esterase biosynthesis in Streptomyces lavendulae H646-SY2

The inhibitory effects of various carbohydrates on cholesterol esterase (CHE) biosynthesis were investigated in a CHE-producing Streptomyces lavendulae H646-SY2. A marked decrease in CHE production and preferential utilization of glucose were observed when glucose was added to a medium containing palmitic acid as the sole carbon source and an inducer of CHE production. This catabolite repression was also caused by other carbohydrates such as sucrose, glycerol, galactose and arabinose. Sucrose, however, did not inhibit the utilization of palmitic acid by the strain, suggesting that the mechanism of the catabolite repression by sucrose is different from that by glucose.

Release of glucagon-like peptide-1 (GLP-1) by carbohydrates in the perfused rat ileum.

The effect of various carbohydrates on glucagon-like peptide-1 (GLP-1) release was studied in the in vivo perfused rat ileum. GLP-1 concentrations in the mesenteric venous effluent increased significantly after luminal perfusion with substrates of a sodium/glucose co-transporter (D-glucose, D-galactose, methyl-alpha D-glucoside, and 3-O-methyl-D-glucose). D-Fructose induced a sodium-independent release of GLP-1. Carbohydrates like 2-deoxy-D-glucose and N-acetyl-D-glucosamine, which are not substrates of a luminal sodium/glucose or fructose transporter, did not affect GLP-1 release. Since methyl-alpha D-glucoside is not a substrate of the basolateral glucose transport mechanism and 3-O-methyl-D-glucose is not metabolized within intestinal cells, it is concluded that intracellular metabolism of carbohydrates and intracellular removal are not essential to induce GLP-1 secretion in rats.

Availability of calcium for absorption in the small intestine and colon from diets containing available and unavailable carbohydrates: an in vitro assessment.

An in vitro method simulating conditions in the small intestine and colon was used to study the effects of various carbohydrates on Ca release from basal diet (BD) containing dairy products. During enzymatic digestion of BD, 28.5 +/- 0.3% of the Ca was released. This was reduced by 3, 22 and 27% by adding bread, psyllium or pectin to BD, respectively (P < 0.05). After enzymatic digestion, the residue from BD was fermented releasing 11.9 +/- 1.2% of the Ca, a value which was significantly less than with pectin (13.7 +/- 0.9%) and greater than with psyllium (4.4 +/- 0.2%) addition. The total Ca release ranged from 26.5 +/- 0.8 to 42.2 +/- 1.0% with bread>BD>pectin>psyllium. Lactulose did not differ significantly from BD. These results suggest that carbohydrates may bind Ca and reduce its availability for absorption in the small intestine. However, if the carbohydrate is fermented, bound Ca may be released for potential absorption in the colon, whereas less fermented carbohydrates may continue to bind Ca in the colon. The in vitro method described may be useful for estimating total Ca availability. However, studies in humans are required to validate these results.

Induction of endo-β-xylanase in the fungus Thermomyces lanuginosus

The effect of various carbohydrates on the production of inducible β-xylanase of Thermomyces lanuginosus was investigated. Xylanase was found to be constitutively produced at a low level and induced by a number of substances. All d-pentoses as well as xylan and xylobiose were identified as inducers. The induction of xylanase by xylan was delayed by about 2 h as compared to the induction by xylose. Xylose, xylobiose, and xylan caused an induction in concentrations from 10.0 to 333.3 mg l −1. The effect of d-lyxose, d-arabinose, d-ribose, and l-arabinose was significantly not as pronounced. d-Xylose is proposed to be a natural inducer. The time for induction was shown to be dependent on the concentration of fungal mycelium. Xylanase induction was subject to glucose repression.

Glycation reaction of aspartate aminotransferase by various carbohydrates in an in vitro system

Effects of various carbohydrates on cytosolic aspartate aminotransferase were studied in an in vitro system. When the purified aminotransferase was incubated with glucose or glucose-6-phosphate, the enzymatic activity and isoelectric points were essentially unaffected. On the other hand, fructose, fructose-6-phosphate, and ribose lowered both the enzymatic activities and isoelectric points in the absence of pyridoxal phosphate, and such alteration of the enzyme was partially prevented by the presence of pyridoxal phosphate. We suggest that these carbohydrates may bind to the Lys258 residue of the enzyme, which is the binding site of pyridoxal phosphate. Glyceraldehyde and dihydroxyacetone had powerful effects on the enzymatic activity and shifted the isoelectric points to the anodic side. In these cases, the addition of pyridoxal phosphate showed little effect on such alterations of the enzyme. Carbohydrates, except for glucose and glucose-6-phosphate, also resulted in fragmentation and polymerization of the enzyme. It was found that six and seven of the lysyl residues of the enzyme per subunit were modified with glyceraldehyde and dihydroxyacetone, respectively, based on the analysis of amino acid composition.

Carbohydrates and human appetite

Experiments indicate that exposure to high-carbohydrate foods can give rise to a clear modulation of the expression of human appetite. The potency and time course of the effects of various carbohydrates on satiety vary with the amount consumed and the chemical structure. There is evidence that this biological effect can modulate the temporal profile of hunger and the eating pattern of meals and snacks. One important issue is the action of carbohydrate foods on satiation (within meals) and satiety (after meals). These effects can be compared with the effects of high-fat foods. The physiological mechanisms through which carbohydrates exert an action on appetite are not completely identified, although plasma glucose values are likely to play a role. The experimental evidence suggests that it is possible to design high-carbohydrate diets that provide good nutrition with adequate control over appetite and a beneficial effect on body weight.

The effects of various carbohydrates on sympathetic activity in heart and interscapular brown adipose tissue of the rat

The present studies were undertaken to determine the effect of various carbohydrates on sympathetic nervous system (SNS) activity. Tritiated-norepinephrine (3H-NE) turnover was measured in heart and interscapular brown adipose tissue (IBAT) of rats fed either chow or chow plus 50% caloric supplements of fructose, sucrose, dextrose, or corn starch. Additional studies were performed to examine whether absorption of carbohydrate plays a role in the SNS response, and to determine whether sweet taste in the from of artificial sweeteners may influence SNS activity. After five to ten days on the respective diets, 3H-NE turnover was increased to a similar extent by all carbohydrates tested (from 38% to 160% greater than controls in different studies). Addition of acarbose (which impairs sucrose absorption) to a sucrose-supplemented diet abolished the SNS stimulatory response, whereas cholestyramine (a drug that blocks fat absorption) had no effect. Finally, the addition of saccharin or aspartame to a chow diet failed to alter SNS activity. Thus, caloric supplementation with several carbohydrates, in addition to sucrose, stimulates both cardiac and IBAT SNS activity, absorption of carbohydrate is required for this effect, and noncaloric sugar substitutes do not alter SNS function.