Cyanobacteria produce a wide range of metabolites of interest for industrial or medical use. The cultivation of freshwater Nostoc cf. linckia yielded 5.4 g/L of a crude exopolysaccharide (cEPS) with a molecular weight of 1.31 × 105 g/mol. Ion-exchange chromatography of cEPS yielded two dominant fractions, EPS-1 and EPS-2, differing in molecular weight. The lower molecular weight fraction (EPS-1) was subjected to structural studies. Results of chemical and spectroscopic analyses showed that three of the four dominant sugars, glucose, galactose and xylose are 1,4-linked in the backbone in the following order: [→4)-β-D-Xylp-(1 → 4)-β-D-Glcp-(1 → 4)-α-D-Galp-(1 → 4)-β-D-Glcp-(1→]n. Terminal mannose residues were identified as side chains linked at C3 of every third backbone xylose and every second glucose is branched at C6 by 3-O-lactyl-β-D-glucuronic acid (nosturonic acid). Antioxidant properties of EPS were tested using two in vitro methods. Both assays showed that the cEPS was more active than purified EPS-1 and EPS-2 fractions and deproteinized EPS.
- MeSH
- antioxidancia chemie MeSH
- bakteriální polysacharidy analýza chemie MeSH
- galaktosa chemie MeSH
- glukosa chemie MeSH
- kyselina glukuronová chemie MeSH
- magnetická rezonanční spektroskopie metody MeSH
- molekulární struktura MeSH
- molekulová hmotnost MeSH
- Nostoc chemie MeSH
- xylosa chemie MeSH
- Publikační typ
- časopisecké články MeSH
The synthesis and biological evaluation of novel guanidino sugars as isonucleoside analogs is described. 5-Guanidino xylofuranoses containing 3-O-saturated/unsaturated hydrocarbon or aromatic-containing moieties were accessed from 5-azido xylofuranoses via reduction followed by guanidinylation with N,N'-bis(tert-butoxycarbonyl)-N''-triflylguanidine. Molecules comprising novel types of isonucleosidic structures including 5-guanidino 3-O-methyl-branched N-benzyltriazole isonucleosides and a guanidinomethyltriazole 3'-O-dodecyl xylofuranos-5'-yl isonucleoside were accessed. The guanidinomethyltriazole derivative and a 3-O-dodecyl (N-Boc)guanidino xylofuranose were revealed as selective inhibitors of acetylcholinesterase (Ki =22.87 and 7.49 μM, respectively). The latter also showed moderate antiproliferative effects in chronic myeloid leukemia (K562) and breast cancer (MCF-7) cells. An aminomethyltriazole 5'-isonucleoside was the most potent molecule with low micromolar GI50 values in both cells (GI50 =6.33 μM, 8.45 μM), similar to that of the drug 5-fluorouracil in MCF-7 cells. Moreover, the most bioactive compounds showed low toxicity in human fibroblasts, further indicating their interest as promising lead molecules.
- MeSH
- acetylcholinesterasa MeSH
- antitumorózní látky * chemie MeSH
- lidé MeSH
- MFC-7 buňky MeSH
- molekulární struktura MeSH
- nádory prsu * MeSH
- vztahy mezi strukturou a aktivitou MeSH
- xylosa chemie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hot water extract from biomass of heterotrophic mutant green alga Parachlorella kessleri HY1 (Chlorellaceae) was deproteinised, and three polysaccharidic fractions were obtained by preparative chromatography. The low-molecular fraction (1.5 × 104g mol-1) was defined mainly as branched O-2-β-xylo-(1→3)-β-galactofuranan where xylose is partially methylated at O-4. Two high-molecular fractions (3.05 × 105 and 9.84 × 104g mol-1) were complex polysaccharides containing α-l-rhamnan and xylogalactofuranan parts in different ratios. The polysaccharides were well soluble in hot water and, upon cooling, tended to self-segregate. Immunomodulatory activities of the obtained fractions were preliminary tested using ELISA, FACS and ImmunoSpot kits. The polysaccharides increased the TNF-α production in melanoma bearing mice with much higher intensity than in healthy mice. This was in agreement with the FACS results on T and B cells indicating their possibly secondary activation by innate immunity cells.
- MeSH
- B-lymfocyty účinky léků imunologie patologie MeSH
- CD antigeny genetika imunologie MeSH
- Chlorophyta chemie MeSH
- imunologické faktory chemie izolace a purifikace farmakologie MeSH
- interferon gama genetika imunologie MeSH
- interleukin-2 genetika imunologie MeSH
- interleukin-4 genetika imunologie MeSH
- lipopolysacharidy antagonisté a inhibitory farmakologie MeSH
- melanom imunologie patologie MeSH
- metylace MeSH
- molekulová hmotnost MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nádory kůže imunologie patologie MeSH
- polysacharidy chemie izolace a purifikace farmakologie MeSH
- primární buněčná kultura MeSH
- regulace genové exprese účinky léků MeSH
- rostlinné extrakty chemie MeSH
- rozpustnost MeSH
- sacharidové sekvence MeSH
- T-lymfocyty účinky léků imunologie patologie MeSH
- TNF-alfa genetika imunologie MeSH
- voda MeSH
- xylosa chemie izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Pentose dehydration and direct transformation of xylan into furfural were performed in a water-cyclopentyl methyl ether (CPME) biphasic system under microwave irradiation. Heated up between 170 and 190 °C in the presence of Nafion NR50 and NaCl, d-xylose, l-arabinose and xylan gave furfural with maximum yields of 80%, 42% and 55%, respectively. The influence of temperature and reaction time on the reaction kinetics was discussed. This study was also completed by the survey of different reactant ratios, such as organic layer-water or catalyst-inorganic salt ratios. The exchange between proton and cation induced by an excess of NaCl was monitored, and a synergetic effect between the remaining protons and the released HCl was also discovered.
Výroba bioethanolu je jedním z často diskutovaných témat současnosti. Možnost jeho získávání z lignocelulosové biomasy - pentosových cukrů, by zvýšilo jeho celkové výnosy a zároveň umožnilo efektivně zpracovávat zemědělský odpad. V posledních 20 letech se výzkum konverze xylosy na ethanol zaměřil zejména na využití rekombinantních kmenů Saccharomyces cerevisiae, dosud ale nebyl nalezen vhodný pro průmyslové využití.
Today, production of bioethanol is one of the most frequently discussed topics. The possibility of obtaining it from lignocellulose biomass - pentose sugars, would increase its total revenue and enable efficient processing of agricultural wastes. In the last 20 years, research on the conversion of xylose to ethanol focused on using recombinant strains of Saccharomyces cerevisiae, but it did not reach suitable conditions for the industrial use.
- MeSH
- nukleosidy chemie MeSH
- stereoizomerie MeSH
- xylosa aplikace a dávkování chemie MeSH
- Publikační typ
- techniky in vitro MeSH
