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Biomedical subjects

S C Ziesenitz

Publications and source records attributed to S C Ziesenitz.

15 recordsLinked to original sources
PubMed1989

Nutritional assessment in humans and rats of leucrose [D-glucopyranosyl-alpha(1----5)-D-fructopyranose] as a sugar substitute.

Leucrose [D-glucosyl-alpha(1----5)-D-fructopyranose], prepared by an enzyme-catalyzed transglycosidation from sucrose with greater than 99% purity, has previously been shown to be noncariogenic and was found in the present study to be apparently easily digestible when given to humans as a single oral dose of 100 g, or when fed to rats at a level of 35 g/kg body wt daily. Weanling rats fed a 25% leucrose diet grew as well as rats fed a diet containing 25% sucrose or corn starch. When 1 g of leucrose was given intravenously to adult rats, 70% of this disaccharide was excreted in the urine within 24 h, and feeding and drinking behavior of the rats was not altered. No adverse effects on their general health were observed. The substrate properties of leucrose for alpha-glucosidase from yeast and for carbohydrases from human jejunal mucosa were determined, and these data were then compared with those of maltose and sucrose. The cleavage rate of leucrose in vitro by human digestive carbohydrases was 31% that of maltose and 63% that of sucrose. Hydrogenated leucrose (leucritol) was cleaved 10 times slower, with a Michaelis constant close to that of leucrose. Blood glucose and fructose profiles in humans given leucrose per os tended to be lower than those in humans given sucrose, while insulin and C-peptide profiles were unaltered.

Administration, Oral↗
PubMed1989

Cariological assessment of leucrose [D-glucopyranosyl-alpha(1----5)-D-fructopyranose] as a sugar substitute.

Leucrose [D-glucosyl-alpha(1----5)-D-fructopyranose] prepared by microbial-enzymatic transglycosidation from sucrose, is the first alpha(1----5)-linked disaccharide which possesses excellent nutritional properties with regard to metabolic utilization and is well tolerated. The aim of the present work was to assess its cariogenic potential. Yeast invertase was shown to be inhibited by leucrose in a noncompetitive way, while hydrogenated leucrose (leucritol) acted as an activator. Plaque polysaccharide forming glucosyltransferases from Streptococcus cricetus AHT were not influenced by leucrose, but by leucritol. Essentially no acid formation was observed after incubation of leucrose with suspensions of human dental plaque, S. mutans NCTC 10449, Lactobacillus casei LSB 132 and Actinomyces viscosus Ny 1 No. 30. Leucrose was a competitive inhibitor of the acid formation from sucrose by S. mutans NCTC 10449 at neutral pH. Furthermore, leucrose inhibited at neutral pH considerably the uptake of sucrose by S. mutans NCTC 10449. The uptake of fructose and maltose was also inhibited but that of glucose not at all. In Cara rats as the animal model, leucrose was compared to sucrose and to corn starch for its cariogenic potential. In sharp contrast to the group fed with 30% sucrose, caries scores of the 30% leucrose group were not significantly different from the starch group. pH telemetry with an indwelling electrode in man proved lueucrose to be 'safe for teeth' since plaque pH did not drop below pH 5.7. Leucrose is a novel noncariogenic disaccharide and thus represents a highly promising sugar substitute for caries prevention.

Actinomyces↗
PubMed1988

Uptake of saccharin and related intense sweeteners by Streptococcus mutans NCTC 10449.

In a 1-octanol/phosphate buffer system, saccharin was much more lipophilic than would be inferred from its dissociation constant which, however, determined the partition behavior of acesulfame and cyclamate. The uptake of saccharin into Streptococcus mutans led to a 30 to 40-fold higher concentration of this intense sweetener within cells than in the incubation medium. Acesulfame and cyclamate were distributed between cells and medium essentially in a diffusion-controlled manner. The uptake of saccharin into S. mutans was found to depend strongly on simultaneous sugar fermentation, and in addition, on external pH, sweetener concentrations, and cell densities. Without glycolysis, caused, for example, by an exhaustion of added sucrose, too acidic external pH, or the addition of glycolysis inhibitors, the uptake of saccharin was diffusion-controlled as in the case of acesulfame and cyclamate. The uptake of saccharin was inhibited by a reversal of the direction of the lactate gradient from in----out to out----in. The activation energy of saccharin uptake into glycolyzing S. mutans was near 18 kJ/mol, while glycolysis itself required 82-98 kJ/mol as activation energy, depending somewhat on experimental conditions. Up to 100 attomol of saccharin per bacterial cell was observed. It was concluded that the cytomembrane of S. mutans was involved in mediating the inhibitory effects of saccharin by an antiport of saccharin into cells in exchange for lactate.

Chromatography, High Pressure Liquid↗
PubMed1987

In vitro assessment of nystose as a sugar substitute.

Nystose represents a fructooligosaccharide with two fructose molecules linked via beta(1----2) bonds to the fructosyl moiety of sucrose. This tetrasaccharide was subjected to an array of in vitro tests designed for the assessment of potential sugar substitutes before animal or human studies. beta-Fructosidase from yeast cleaved nystose at about 5% of the initial rate observed with sucrose. The terminal fructose was released first. Glycosyltransferase from Streptococcus mutans #620 did not utilize nystose for the formation of a glucan-type polysaccharide. Anaerobic fermentation of nystose by a suspension of mixed dental plaque microorganisms and by S. mutans NCTC 10449 was about half as fast as with sucrose. Thin-layer chromatography at various reaction times with S. mutans NCTC 10449 indicated the terminal fructose as the site of first attack. Analyses for free monosaccharides confirmed these data because free fructose exceeded free glucose at early reaction times far more than would follow from the 3:1 ratio of fructose to glucose in the nystose molecule. High pressure liquid chromatography assays demonstrated lactic and acetic acids as the main fermentation products. Carbohydrases from human jejunal mucosa did not attack nystose. However, cecal anaerobic microorganisms of the rat fermented nystose rapidly into acids.

Animals↗
PubMed1986

[A stepwise method of evaluating sugar substitutes--a preliminary study using enzymes. 1. Alpha-glucosidase from yeast].

alpha-Glucosidase from yeast was checked for its catalytic potency under a variety of experimental conditions. Michaelis constants and maximal velocities are reported for 7 disaccharides of the glucosyl-fructosyl or glucosyl-glucosyl type, 4 disaccharide alcohols, and 2 mixtures of each 2 disaccharide alcohols. Reduction of a carbonyl group is of less importance for the substrate properties than the type of the glycoside bond; consequences for the suitability of potential sugar substitutes are derived.

Disaccharides↗
PubMed1986

[A stepwise method of evaluating sugar substitutes--a preliminary study using enzymes. 2. Beta-fructosidase from yeast].

No D-glucosylfructoses except sucrose, neither the alpha(1----1)- nor the alpha(1----3)- or the alpha(1----5)- or the alpha(1----6)-disaccharide possess substrate properties for beta-fructosidase from yeast. The two latter ones, leucrose and isomaltulose, however, are non-competitive (leucrose) or uncompetitive (isomaltulose, Palatinose) inhibitors of beta-fructosidase from yeast. Due to the high substrate specificity of invertase, assays of its activity have predictive power for cariological aspects of sugar substitutes carrying glycoside bonds between glucose and fructose.

Disaccharides↗
PubMed1986

[A stepwise method of evaluating sugar substitutes--a preliminary study using enzymes. 3. Carbohydrases from the human jejunal mucosa].

Mixed carbohydrases from human jejunal mucosa were characterized by Michaelis constants and maximal velocities of hydrolysis of 15 disaccharides and disaccharide alcohols, mainly of the glucosylfructose series. The presumed fate of such substances after oral ingestion may be foreseen from the km and vmax data. There is principal agreement that wholesomeness in man and animals as well as energetic utilization of disaccharides and split products correlate well with the enzymological data. Therefore the metabolic fate of sugar substitutes in the human body is partially predictable from such enzymic studies.

Disaccharidases↗
PubMed1985

Acesulfame K, cyclamate and saccharin inhibit the anaerobic fermentation of glucose by intestinal bacteria.

The caecal microflora of Cara rats was incubated in the pH stat with glucose under anaerobic conditions, and the acid production was measured. In the presence of the sweeteners Acesulfame K, Cyclamate and Saccharin, inhibition of the fermentation of glucose was observed with ED50 values of 260, 251, and 140 mM, respectively. The nutritional relevance of these observations is probably slight; an interpretation in terms of bacterial physiology leads to the proposal that the sweeteners may act on glucose transport systems at the bacterial cytomembrane.

Anaerobiosis↗