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Marta Pitek-Hnat Kuba Bomba Janusz P. Kowalski-Stankiewicz Jakub Pksiski Agnieszka Kozowska Jacek G. Sonicki Tomasz J. Idzik Beata Schmidt Krzysztof Kowalczyk Marta Walo Grzegorz Mikoajczak Agnieszka Kochmaska 《Materials》2021,14(7)
Poly(xylitol dicarboxylate-co-diol dicarboxylate) elastomers can by synthesized using wide variety of monomers with different chain lengths. Obtained materials are all biodegradable, thermally stable elastomers, but their specific properties like glass transition temperature, degradation susceptibility, and mechanical moduli can be tailored for a specific application. Therefore, we synthesized eight elastomers using a combination of two dicarboxylic acids, namely suberic and sebacic acid, and four different diols, namely ethanediol, 1,3-propanediol, 1,4-buanediol, and 1,5-pentanediol. Materials were further modified by e-beam treatment with a dose of 100 kGy. Materials both before and after radiation modification were tested using tensile tests, gel fraction determination, 1H NMR, and 13C NMR. Thermal properties were tested by Differential Scanning Calorimetry (DSC), Dynamic Thermomechanical Analysis (DMTA) and Thermogravimetric Analysis (TGA). Degradation susceptibility to both enzymatic and hydrolytic degradation was also determined. 相似文献
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《Acta odontologica Scandinavica》2013,71(6):397-403
The aim was to study eventual physico-chemical changes occurring in whole saliva due to sweetened and unsweetened stimulators. The assay was carried out in 10 female subjects with regard to changes of pH, buffering capacity and electrolytes in saliva as influenced by chewing of fructose, sucrose, sorbitol and xylitol gum, gum base and paraffin. The flow rate of saliva was measured in relation to use of xylitol and sucrose chewing gum and unsweetened gum base. These sweeteners increased significantly the salivary flow rate in comparison to the unsweetened gum base. Generally, xylitol and sorbitol on one hand, and sucrose and fructose on the other, behaved in an almost similar way. Increased buffering capacity and elevation of pH in saliva was found in the presence of the polyols tested. 相似文献
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Kurola P Tapiainen T Sevander J Kaijalainen T Leinonen M Uhari M Saukkoriipi A 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2011,119(2):135-142
Xylitol inhibits the growth of Streptococcus pneumoniae. In clinical trials, xylitol decreased the occurrence of acute otitis media in day-care children, but did not decrease nasopharyngeal carriage of pneumococci. We hypothesized that xylitol inhibits biofilm formation of pneumococci, and measured biofilm formation and gene expression levels of the capsule gene cpsB and two other genes: autolysin encoding gene lytA and competence gene comA in different growth media in vitro. Twenty pneumococcal isolates were grown on polystyrene plates for 18 h in test media containing 0.5% xylitol, 0.5% glucose, 0.5% xylitol and 0.5% glucose, 0.5% fructose, 0.5% xylitol and 0.5% fructose or brain heart infusion (BHI) medium supplemented with 10% horse serum. Gene expression levels were measured after 5 h of growth using a relative quantification method with calibrator normalization. Exposure to xylitol lowered OD values, which were used as an indication of biofilm, compared with BHI medium, but when the medium was supplemented with glucose or fructose, biofilm formation was enhanced and the inhibitory effect of xylitol on biofilm formation was not observed. Xylitol also lowered lytA expression levels. Changes in biofilm formation in response to different sugar compounds may partly explain the efficacy of xylitol to prevent acute otitis media in previous clinical trials. 相似文献
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Xylitol inhibition of anaerobic acid production by Streptococcus mutans at various pH levels 总被引:1,自引:0,他引:1
Xylitol inhibits the glycolysis and growth of Streptococcus mutans. We studied the inhibitory effect of xylitol on the acid production of S. mutans at several pH levels under the strictly anaerobic conditions found in the deep layer of dental plaque. Xylitol inhibited the rate of acid production from glucose and changed the profile of acidic end products to formate-acetate dominance, with a decrease in the intracellular level of fructose 1,6-bisphosphate and an intracellular accumulation of xylitol 5-phosphate (X5P). These results were notable at pH 5.5-7.0, but were not evident at pH 5.0. Since the activity of phosphoenolpyruvate phosphotransferase for xylitol was greater at higher pH, it is suggested that xylitol could be incorporated more efficiently at higher pH and that the resultant accumulation of X5P could inhibit the glycolysis of S. mutans more effectively. 相似文献
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The aim of the present study was to examine xylitol metabolism by dental plaque collected immediately after the use of xylitol gum. Plaque was collected from 12 individuals immediately before and after xylitol exposure. The effect on xylitol metabolism by dental plaque of a 3 d discontinuation of the xylitol exposure was also examined. Xylitol metabolism by the plaque suspensions was initiated by adding [14 C]xylitol and analyzed by HPLC. The results showed increased xylitol metabolism after 11 wk of chewing xylitol-containing gum. The ability to metabolize xylitol was rapidly reduced after the discontinuation of the xylitol exposure. It is suggested that an induction of enzymes in one or more of the species of plaque bacteria may have caused this effect. Glucose metabolism, which also was studied in the plaque samples, was decreased after xylitol exposure, but increased again 3 d after cessation of the xylitol exposure. It is suggested that the reduced glycolysis was caused by accumulation of intracellular xylitol-5-phosphate in some plaque bacteria during the xylitol exposure. 相似文献
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Xylitol-induced elevated expression of the gbpC gene in a population of Streptococcus mutans cells 总被引:1,自引:0,他引:1
Xylitol possesses a unique property distinct from the other caries-preventive sweeteners. This sugar alcohol cannot be metabolized to acids but is taken up by Streptococcus mutans and accumulated as a toxic sugar-phosphate in the cells, resulting in growth inhibition. Due to the accumulation, xylitol induces biological responses including the emergence of xylitol-insensitive populations. Therefore, we expected another response induced by xylitol and found a new phenomenon, that cells repeatedly cultured in the presence of xylitol evolved into those exhibiting an elevated dextran-dependent aggregation phenotype. This phenotype was found to result from expression of the gbpC gene, which was previously reported to be expressed only under certain stress conditions. Construction of a Strep. mutans isogenic mutant carrying the gbpC::lacZ fusion gene indicated that gbpC expression of cells repeatedly cultured in the presence of xylitol was elevated 20-fold. DNA transfer experiments indicated that this phenotypic change did not appear to be due to a mutation. These cells also exhibited decreased adhesion to glass surfaces when grown in the presence of sucrose. This may be one of the ways by which some populations of Strep. mutans are removed from dental plaques. 相似文献
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