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Sugar composition of O-antigenic lipopolysaccharides isolated from Vibrio parahaemolyticus.

Vibrio parahaemolyticus, a causative bacterium of food poisoning unique for its particular primary association with sea products, is now divided serologically into 11 or 12 O-forms based on agglutination and agglutinin-absorption tests. We determined the sugar composition of the somatic O-antigens, i.e., lipopolysaccharides (LPS), of representative strains of each O-form. Of particular interest is the absence of evidence for the presence of 2-keto-3-deoxy-octonic acid (KDO), a regular sugar component of gram-negative bacterial LPS, in any LPS examined, with the exception of 06. Furthermore, 07 and 012 LPS contained a KDO-like compound that is, however, not identical with KDO. Glucose, glucosamine, and L-glycero-D-mannoheptose were found as common sugar constituents. Three unidentified amino sugars, designated here as P1, P2, and P3, were found. Various combinations of each of these unidentified amino sugars, and of galactose, fucose, arabinose, D-glyucero-D-mannoheptose, galactosamine, KDO, and the KDO-like substance were detected in accordance with the O-form of LPS. On the basis of the sugar composition, LPS of the 12 O-forms of V. parahaemolyticus can be classified into nine chemotypes, because 03, 05, and 011 LPS belong to the same chemotype and 07 and 012 to another chemotype.

Antigens, Bacterial↗

Starvation-induced stimulation of sugar uptake in Streptococcus mutans is due to an effect on the activities of preexisting proteins of the phosphotransferase system.

We examined the effects of sugar concentration in the medium on sugar uptake and phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS) activities in Streptococcus mutants GS-5. Kinetic analyses of sucrose uptake in cells harvested under conditions of sucrose excess or sucrose limitation showed that increased uptake under the latter condition was almost completely due to an increase in the Vmax of the high-affinity PTS. In a series of experiments in which cells growing under conditions of sucrose or glucose excess were shifted to a medium lacking sugar, starvation resulted in a stimulation of sugar uptake and a parallel increase in PTS activity. These starvation-induced increases in PTS-mediated uptake were not affected by the presence of either chloramphenicol or rifampin during the starvation period, indicating that neither protein nor RNA synthesis was necessary for the stimulation. In vivo labeling experiments with 32Pi revealed that uptake stimulation during starvation was accompanied by a loss of acid-stable phosphate covalently bound to the phosphocarrier protein HPr of the PTS. We conclude, therefore, that stimulation of PTS-mediated uptake of sucrose and glucose during sugar limitation in S. mutans GS-5 is at least partially the result of increased activities of preexisting PTS proteins and that this may be due, at least in part, to dephosphorylation of a previously identified site in S. mutans HPr that can be phosphorylated by an ATP-dependent kinase.

Biological Transport, Active↗

Adenylate cyclase is required for chemotaxis to phosphotransferase system sugars by Escherichia coli.

We report that in Escherichia coli, chemotaxis to sugars transported by the phosphotransferase system is mediated by adenylate cyclase, the nucleotide cyclase linked to the phosphotransferase system. We conclude that adenylate cyclase is required in this chemotaxis pathway because mutations in the cyclase gene (cya) eliminate or impair the response to phosphotransferase system sugars, even though other components of the phosphotransferase system known to be required for the detection of these sugars are relatively unaffected by such mutations. Moreover, merely supplying the mutant bacteria with the products of this enzyme, cyclic AMP and cyclic GMP, does not restore the chemotactic response. Because a residual chemotactic response is observed in certain strains with residual cyclic GMP synthesis but no cyclic AMP synthesis, it appears that the guanylate cyclase activity rather than the adenylate cyclase activity of the enzyme may be required for chemotaxis to sugars transported by the phosphotransferase system. Mutations in the cyclic nucleotide phosphodiesterase gene, which increase the level of both cyclic AMP and cyclic GMP, also reduce chemotaxis to these sugars. Therefore, it appears that control of the level of a cyclic nucleotide is critical for the chemotactic response to phosphotransferase system sugars.

3',5'-Cyclic-AMP Phosphodiesterases↗

Renal sugar transport in the winter flounder. II. Galactose transport system.

The structural specificity of the transport of 0.5 mM D-galactose and 2-deoxy-D-galactose by teased renal tubules of the winter flounder Pseudopleuronectes americanus was investigated. The sugar uptake reflects preponderantly transport at the antiluminal membrane of tubular cells. Both sugars compete for the transport sites, indicating the sharing of a common carrier. 1) The structural requirements for the hexose-carrier interaction were defined by an inhibiton analysis using 12 structurally analogous sugars (5 mM): a (pyranose) ring structure; a free hydroxyl on C1; free hydroxyls (equatorial configuration) on C3 and C4; an oxygen on C6. Close packing in the vicinity of C2 is indicated. 2) Consonant with the requirement of a free C1-OH, beta-methyl-D-galactoside is not transported 3) Increasing concentrations (0.05-0.5 mM) of phlorizin and phloretin inhibit sugar uptake by lowering cellular levels of phosphorylated hexoses, whereas the levels of free sugars are not depressed. The possibility of an interaction of the sugar at C1-0H with a phosphorylated group at the carrier as the first step in the translocation process of both hexoses across the basal membrane is raised.

Animals↗

The effect 3,5,3'-triiodo-L-thyronine on the kinetic parameters of sugar transport in cultured chick embryo heart cells.

The effect of 3,5,3'-triiodo-L-thyronine (T3; 10(-8)M) on sugar transport was studied in cultured chick embryo heart cells. T3 did not increase the uptake of L-glucose, a sugar which enters the cell by simple diffusion. The effect of T3 on the kinetic parameters of the uptake of both 3-0-methyl-D-glucose (3-OMET) and 2-deoxy-D-glucose (2-DOG) was studied after 6 and 24 h exposure to T3. T3 had no effect on the Km for either sugar. T3 increased the Vmax for the first 6 h or exposure for 3-OMET, a sugar which is only transported, and increased the Vmax after 6 and 24 h for 2-DOG, a sugar both transported and phosphorylated. T3 also increased the relative phosphorylation of 2-DOG within the cells in the period between 6 and 24 h. The data show a biphasic effect of T3 on sugar accumulation, an early effect on transport along and a later effect on phosphorylation as well.

Animals↗

A novel UDP-sugar, UDP-3-ketoglucosamine or UDP-4-ketoglucosamine, from bovine heart muscle reduces metmyoglobin with NAD(P)H.

3-Ketoglucose and similar ketosugars have been identified in microorganisms only and little is known about their functions. UDP-sugars are widely found as an intermediate in sugar metabolism in living organisms. Yet what role UDP-sugars play, or whether they play a direct role in metabolism, is still unknown. UDP-sugars were isolated and purified from bovine heart muscle, and a UDP-sugar fraction capable of NAD(P)H-dependent catalytic reduction of metmyoglobin was detected. Subsequent identification revealed that the active UDP-sugar was UDP-3- or UDP-4-ketoglucosamine. These compounds were purified from bovine cardiac muscle by ultrafiltration, anion-exchange column chromatography and reverse-phase chromatography. They were further characterized by determination of their chemical reducing activity, by comparison with synthetic UDP-3- or UDP-4-ketoglucosamine standards using high-performance liquid chromatography, by estimation of molecular mass using fast atom bombardment mass spectrometry, and by Fourier transform infrared microspectroscopy and electron probe microanalysis. The results suggest that UDP-3- or UDP-4-ketoglucosamine reduces metmyoglobin in bovine cardiac muscle. It is important that the reducing activity displayed by this ketosugar is not the effect of UDP-3- or UDP-4-ketoglucosamine alone but depends on NAD(P)H. In other words, this action of UDP-3- or UDP-4-ketoglucosamine is catalytic.

Animals↗

The formation of DNA sugar radicals from photoexcitation of guanine cation radicals.

In this investigation of radical formation and reaction in gamma- irradiated DNA and model compounds, we report the conversion of the guanine cation radical (one-electron oxidized guanine, G(.+)) to the C1' sugar radical and another sugar radical at the C3' or C4' position (designated C3'(.)/C4'(.)) by visible and UV photolysis. Electron spin resonance (ESR) spectroscopic investigations were performed on salmon testes DNA as well as 5'-dGMP, 3'-dGMP, 2'-deoxyguanosine and other nucleosides/nucleotides as model systems. DNA samples (25- 150 mg/ml D(2)O) were prepared with Tl(3+) or Fe(CN)(3-)(6) as electron scavengers. Upon gamma irradiation of such samples at 77 K, the electron-gain path in the DNA is strongly suppressed and predominantly G(.+) is found; after UV or visible photolysis, the fraction of the C1' sugar radical increases with a concomitant reduction in the fraction of G(.+). In model systems, 3'- dGMP(+.) and 5'-dGMP(+.) were produced by attack of Cl(.-)(2) on the parent nucleotide in 7 M LiCl glass. Subsequent visible photolysis of the 3'-dGMP(+.) (77 K) results predominantly in formation of C1'(.) whereas photolysis of 5'-dGMP(+.) results predominantly in formation of C3'(.)/C4'(.). We propose that sugar radical formation is a result of delocalization of the hole in the electronically excited base cation radical into the sugar ring, followed by deprotonation at specific sites on the sugar.

Animals↗

Development and validation of whole-genome SSR markers in sugar beet (Beta vulgaris L.).

Sugar beet (Beta vulgaris L.) is an important sugar and cash crop worldwide. To systematically characterize SSR (Simple Sequence Repeat) loci across sugar beet chromosomes and enable the precise identification of germplasm resources, this study conducted a genome-wide scan for SSR loci, analyzed their distribution patterns, and determined their genotypes using resequencing data from 123 sugar beet varieties. The results revealed an abundance of SSR loci in the sugar beet genome, with a total of 135, 379 identified, from which 135, 344 pairs of SSR primers were designed (135, 344 primer pairs successfully designed; 35 loci failed to meet design criteria). Specifically, 31, 748 primer pairs were designed based on SSRs located in unassigned scaffolds, and 103, 596 primer pairs from SSRs assigned to the nine chromosomes. Through bioinformatic analysis, we identified 28, 768 SSR primers located in multi-copy genes with PIC (Polymorphism Information Content) ≥ 0.5, and 2, 326 SSR markers located in single-copy genes residing in various genic regions (among which 543 had PIC ≥ 0.5, with the highest reaching 0.776). PCR (Polymerase Chain Reaction) validation confirmed 20 robust and polymorphic markers producing clear and reproducible bands. Among them, 10 SSR primers located in multi-copy genes exhibited three or more polymorphic types, and 10 markers located in single-copy genes displayed 2-3 polymorphic types. The most polymorphic marker, YCD-4-2, detected 11 polymorphic types across 48 varieties. Furthermore, to explore markers with potential functional significance, we annotated the genes harboring SSR markers located in single-copy genes. The results showed that 1, 264 SSRs located in single-copy genes were localized to 967 genes, which are significantly enriched in pathways related to carbohydrate metabolism, stress responses, and plant-pathogen interactions. The 20 validated markers and the 2, 326 SSRs located in single-copy genes provided in this study can be directly applied to fingerprinting of sugar beet varieties, seed purity testing, and marker-assisted selection, thus representing a practical resource for molecular breeding.

genome-wide↗

Microbiological aspects of some caloric sugar substitutes.

Several caloric sugar substitutes are available today, e.g. maltitol, Lycasin, sorbitol, xylitol, palatinit, sorbose, coupling sugar, palatinose, fructose and invert sugar. When evaluating the cariogenicity of these sugar substitutes from a bacteriological point of view, different analytical procedures should be considered. In vitro studies on the capacity of pure oral bacterial strains and dental plaque material to decompose the substitute to acid. Studies on the catabolism of the substitute. Possible adaptation of the oral microflora to metabolize the substitute in vivo as well as in vitro. Studies on any inhibitory effect of the substitute on the microbial activities in dental plaque and on the oral microflora. The capacity of oral bacteria, e.g. Streptococcus mutans, to induce caries in animal experiments should also be considered. Results from such microbiological studies make it possible to classify the caloric sugar substitutes into different groups. The first, most suitable, group seems to consist of xylitol and sorbose. These substitutes are fermented by few oral bacteria and no negative adaptation of the oral flora has been observed. A reducing effect upon dental plaque formation and on acid production from glucose has been reported. A second group consists of maltitol, palatinite, palatinose, sorbitol and Lycasin. These substitutes are fermented by certain groups of organisms within the oral genera Actinomyces, Lactobacillus and Streptococcus. Adaptation of oral bacteria to palatinose and to sorbitol, resulting in a more pronounced acid production, has been observed. No inhibitory effects have been reported. The results from experimental studies suggest that these sugar substitutes have no or little cariogenic action in rodents inoculated with S. mutans.(ABSTRACT TRUNCATED AT 250 WORDS)

Acids↗

Effect of amino sugars on platelet aggregation and on fibrinogen binding.

The amino sugars glucosamine, galactosamine and mannosamine (30 mM) inhibited aggregation of human or rabbit platelets induced by ADP, collagen, thrombin, PAF or high concentrations of sodium arachidonate. 125I-fibrinogen binding during ADP-induced aggregation, and release of amine storage granule contents were also inhibited. Increasing the calcium concentration of the suspending medium to 5 mM did not overcome the inhibitory effect on the release reaction. The amino sugars deaggregated rabbit platelets that had been aggregated by ADP, collagen or thrombin, but deaggregated human platelets readily only when ADP was used as the aggregating agent. Fibrinogen-induced aggregation of chymotrypsin-treated platelets was blocked by the amino sugars. They did not inhibit platelet adherence to a collagen-coated glass surface, nor affect release of granule contents from the adherent platelets. Aggregation and release induced by low concentrations of sodium arachidonate or the divalent cation ionophore A23187 were potentiated, indicating that the effects of the amino sugars on platelets are more complex than simple inhibition of the lectin-like activity that becomes available on the surface of platelets that have undergone the release reaction. One of the effects of the amino sugars, however, is interference with the binding of fibrinogen to platelets. The effects of the amino sugars are shared by other primary amines.

Adenosine Diphosphate↗

Substitution of sugar cane bagasse in the chicken diet and immune response.

Total proteins and protein electrophoresis were made in the sera of broiler chicken (Arber Acres) to evaluate the effect of substitution of basal diet for 4 weeks by either 8% sugar cane bagasse +2% wheat germ or 16% sugar cane bagasse +4% wheat germ whether untreated or incubated with rumen liquor for 72 h and then sterilized with 2 Mrad gamma-irradiation (treated). Both levels of untreated sugar can bagasse (8 and 16%) showed significant decrease in gamma globulins but this decrease had no effect on broiler chicken (45 days) while there was significant increase in total proteins in treated sugar cane bagasse 8% with concomitant increase in alpha 2, beta 1, beta 2 and gamma globulins. These results denoted that addition of rumen liquor to 8% sugar cane bagasse diet have resulted in an improvement in the transportation of micro nutrients and immune response most probably due to its high content of microorganisms constituting high quality animal protein; also more vaccines were recommended in feeding of chicken with sugar cane bagasse for a longer period e.g. laying hens to overcome its suppressive effect on the gamma globulins.

Animals↗

Bacterial adherence to cell surface sugars.

Bacterial adherence to animal cell surfaces is of interest because of its relation to pathogenicity and the insight it provides into determinants of intercellular recognition. The attachment of various strains of Escherichia coli and Salmonella spp. to epithelial cells and phagocytes is inhibited by D-mannose, and the adherence of other bacteria is inhibited by sugars such as L-fucose and D-galactose, suggesting that sugar-mediated adherence is widespread. This intercellular recognition is thought to be mediated by sugar residues (e.g. D-mannose) on the surface of animal cells, to which bacteria attach by a sugar-binding substance on their surface. The nature of the receptors on the animal cells is unknown. There is evidence that E. coli produces lectin-like substances specific for D-mannose, by which it binds to the cells. The most common form of these lectin-like substances appears to be the bacterial pili, which can be reversibly dissociated into their protein subunits. The lectin can also be in the form of bacterial flagella or tightly attached to the outer membrane of the bacteria. Mannose-specific attachment may assist bacteria in colonizing and invading their hosts: methyl alpha-D-mannoside (but not methyl alpha-D-glucoside) significantly reduced infection of the urinary tract of mice by virulent strains of E. coli. Once bacteria penetrate the host their ability to binding sugars on phagocytes may impair their virulence by facilitating phagocytosis. Further studies of the sugar-mediated bacterial adherence by organisms growing in vivo and the structural identification of the host cell receptors may lead to the design of more effective adherence inhibitors that may help to prevent certain bacterial infections.

Adhesiveness↗

Effect of sugar type on the survival of frozen-thawed rhesus monkey (Macaca mulatta) sperm.

Sperm-freezing extenders supplemented with sugar or a combination of different sugars are widely used for the cryopreservation of nonhuman primate spermatozoa. Understanding which sugar or combination of sugars offers the highest level of cryoprotection would be beneficial for the development of sperm-freezing extenders. In the present study we aimed to investigate the effect of glucose, lactose, and raffinose separately or in combination on the cryosurvival of rhesus monkey spermatozoa. Toward that end, we prepared eight extenders by adding various types of sugars to a basic medium (BM): G-BM (0.3 M glucose), L-BM (0.3 M lactose), R-BM (0.3 M raffinose), LG-BM (0.15 M lactose+0.15 M glucose), RG-BM (0.15 M raffinose+0.15 M glucose), LR-BM (0.15 M lactose+0.15 M raffinose), and LRG-BM (0.1 M lactose+0.1 M raffinsoe+0.1 M glucose). A saline control (0.157 M sodium chloride) was also used. The results showed no significant difference in post-thaw motility when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, but the post-thaw motility was significantly lower when it was frozen with R-BM, LR-BM, and the saline control. The highest plasma membrane integrity was achieved when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, and the highest acrosome integrity was achieved with G-BM, L-BM, LG-BM, RG-BM, LRG-BM, and the saline control. The results indicate that the various sugars offered different protective effects. For the cryopreservation of rhesus monkey spermatozoa, glucose (monosaccharide) and lactose (disaccharide) were shown to be more suitable than raffinose (trisaccharide) for preserving spermatozoal motility, plasma membrane, and acrosome. Specifically, raffinose was detrimental to sperm acrosome integrity.

Acrosome↗

Induction of apoptosis in human leukemia cells by naturally fermented sugar cane vinegar (kibizu) of Amami Ohshima Island.

Naturally fermented vinegar such as Kibizu (sugar cane vinegar in Amami Ohshima, Japan), Kurozu (black rice vinegar in Kagoshima, Japan), Kouzu (black rice vinegar in China) and red wine vinegar in Italy had potent radical-scavenging activity analyzed by DPPH method. For the elucidation of food factor for cancer prevention contained in naturally fermented vinegar, the induction of apoptosis in human leukemia cell HL-60 was investigated with sugar cane vinegar Kibizu. Fraction eluted by 40% methanol from Amberlite XAD 2 chromatography of sugar cane vinegar showed potent radical scavenging activity. The fraction also showed the activity repressing growth of typical human leukemia cells such as HL-60, THP-1, Molt-4, U-937, Jurkat, Raji and K-562. On the other hand, the fraction did not have any growth inhibition activity against human fetal lung cell TIG-1. The most potent radical-scavenging activity and the growth repression activity of the leukemia cell were observed in the same chromatographic fraction of methanol 40%. From cell sorting FACS analyses, electron microscopic observations and cytochemical staining of chromatin and nuclear segments in human leukemia cell HL-60 treated with the active fraction, it was concluded that apoptosis was induced in the leukemia cell by the fraction of sugar cane vinegar and resulted in the repression of growth of the human leukemia cells. Chromatographic fraction of sugar cane juice eluted by 20% methanol showed potent activities of radical-scavenging and growth repression of HL-60. These results led us the consideration that active components in sugar cane juice could be converted to more lipophilic compounds with activity to induce apoptosis in HL-60 by microbial fermentation with yeast and acetic acid bacteria.

Acetic Acid↗

Influence of electrostatic interactions on the sugar-phosphate backbone conformation in DNA.

The influence of sugar ring flexibility in DNA on the mechanism of the B <===> A conformational transition is studied. The dipole moment of the deoxyribose as a function of its puckered states is calculated by the quantum-mechanical method using the MINDO/3 approximation. The interaction of the sugar dipole with the neighbor molecular groups in polynucleotide chains is estimated. The sugar dipole interaction with phosphate groups and counterions is shown to be strong and capable to deform the pseudorotation potential of deoxyribose. The effective pseudorotation potential of sugar ring in the B and A helices is obtained. The results are used to explain the behavior of Raman bands in the region of sugar-phosphate vibrations. The mechanism of the effect of electrostatic forces on the sugar-phosphate backbone conformation, which is essential for the B <===> A and other structure transitions, is offered.

Calorimetry↗

Reduced protein adsorption at solid interfaces by sugar excipients.

Sugar excipients are shown to reduce the adsorption of ribonuclease A, bovine serum albumin, and hen egg white lysozyme at the liquid-solid interface. The amount of protein adsorbed decreased as the concentration of the sugar increased. At the same sugar concentration, the ability of sugars to reduce protein adsorption followed the trend: trisaccharides > disaccharides > 6-carbon polyols > monosaccharides. This trend in adsorbed protein amounts among sugars was explained by stabilization of the protein native state in solution by the sugar excipients. The heat of solution of the amorphous saccharide was found to correlate with the amount of protein adsorbed.

Adsorption↗

Enzymatic basis of sugar structures of alpha-fetoprotein in hepatoma and hepatoblastoma cell lines: correlation with activities of alpha 1-6 fucosyltransferase and N-acetylglucosaminyltransferases III and V.

alpha-Fetoproteins (AFPs) were purified from 2 hepatoma cell lines (Hep G2 and HuH-7) and a hepatoblastoma cell line (HuH-6), and the structures of pyridylaminated (PA) derivatives of their sugar chains were analyzed by HPLC. Simultaneously, the activities of alpha 1-6 fucosyltransferase (alpha 1-6FT) and N-acetylglucosaminyltransferase III (GnT-III), IV (GnT-IV) and V (GnT-V) were assayed in these cell lines. For all 3 cell lines the major sugar chain detected was a fucosylated biantennary structure. Hep G2 cells contained a high level of GnT-V, which catalyzes the formation of a tri'-antennary structure, and in fact a substantial percentage of the AFP sugar chains in these cells had the tri'-antennary structure. alpha 1-6FT was also high, and fucosylated tri' structures were detected, which suggests that high activities of transferases affect the AFP sugar chains. In HuH-6 cells, GnT-III, which catalyzes the formation of bisecting GlcNAc, was elevated. Correspondingly, a fucosylated, bisected biantennary structure was found as a major sugar chain. In the HuH-7 cell line, the contents of bisecting GlcNAc and tri' structure were low and neither GnT-III nor GnT-V was elevated. These data indicate that the sugar structures of AFP in these cell lines correlate well with the activities of alpha 1-6 FT, GnT-III and GnT-V.

Carbohydrates↗

Sugar-mediated chitosan/poly(ethylene glycol)-beta-dicalcium pyrophosphate composite: mechanical and microstructural properties.

The microstructural and mechanical properties of sugar-mediated chitosan/poly(ethylene glycol)-based scaffolds and composites, which are composed of beta-dicalcium pyrophosphate (beta-DCP) and sugar-mediated scaffolds, were investigated. All of the scaffolds were prepared by various freeze-drying protocols. The differences in the freeze-drying process of the sugar-mediated chitosan/poly(ethylene glycol) scaffold for three types of sugar (sucrose, glucose, and D-fructose) were determined by scanning electron microscopic observation, water retention, density, and porosity analyses. The sugar-mediated scaffolds prepared by scheme I of the freeze-drying process show large pores, poorly connective interlayers, and disintegrated inner structures, different from the small pores and well-connective channel structures as shown in the scheme II freeze-drying process. The key factors for controlling pore structure and size in the scheme I freeze-drying process were formulation and composition, but for the scheme II freeze-drying process, the key factor was freeze protocol. The composite scaffolds were macroporous, and the microstructure changed considerably with added beta-DCP content. The incorporation of beta-DCP granules caused a significant enhancement of compressive modulus and yield strength. The increased mechanical strength may be attributable not only to the physical complexation between the sugar-mediated scaffold and beta-DCP, but also the chemical reaction to apatite formed on the cell wall.

Biodegradation, Environmental↗