Search results for "Sulfation"
showing 10 items of 26 documents
Structural determination of the lipo-chitin oligosaccharide nodulation signals produced by Rhizobium giardinii bv. giardinii H152
2003
Abstract Rhizobium giardinii bv. giardinii is a microsymbiont of plants of the genus Phaseolus and produces extracellular signal molecules that are able to induce deformation of root hairs and nodule organogenesis. We report here the structures of seven lipochitooligosaccharide (LCO) signal molecules secreted by R. giardinii bv. giardinii H152. Six of them are pentamers of GlcNAc carrying C 16:0 , C 18:0 , C 20:0 and C 18:1 fatty acyl chains on the non-reducing terminal residue. Four are sulfated at C-6 of the reducing terminal residue and one is acetylated in the same position. Six of them are N -methylated on the non-reducing GlcN residue and all the nodulation factors are carbamoylated o…
THE DISTRIBUTION OF UDP-GLUCURONOSYLTRANSFERASES IN RAT-LIVER PARENCHYMAL AND NONPARENCHYMAL CELLS
1992
Activities for the glucuronidation of 1-naphthol, morphine and bilirubin as well as for the sulfation of 2-naphthol have been determined in homogenates of parenchymal, Kupffer and endothelial cells isolated from livers of untreated and Aroclor 1254-pretreated rats. In addition, Western blot analyses using different polyclonal antibodies against UDP-glucuronosyltransferases (UDP-GTs) were performed with similar preparations. All enzymes under investigation were expressed at high levels in liver parenchymal cells. The constitutive expression and inducibility of UDP-GT isozyme(s) for 1-naphthol glucuronidation was also clearly demonstrated in Kupffer and endothelial cells. Furthermore, the pre…
A barium method for the cytochemical detection of sulfated glycosaminoglycans in mast cells and basophilic leukocytes.
1999
Barium ions precipitate inorganic as well as organic sulfate compounds and they can be detected by a reaction with sodium rhodizonate. In this work, we describe the use of a barium method for the selective demonstration of sulfated glycosaminoglycans in cytoplasmic granules of mast cells and basophilic leukocytes. Methanol-fixed smears of mouse peritoneal mast cells and rat bone marrow basophils were treated with 5% BaCl2 for 10 min, followed by staining with either 0.2% sodium rhodizonate in 50% ethanol for 2 h at 60 degrees C, or 0.01% brilliant green in distilled water for 1 min. Light microscopic observation revealed a strong staining reaction of the cytoplasmic granules of these cell t…
Dose-dependent metabolic disposition of hydroxytyrosol and formation of mercapturates in rats
2013
Hydroxytyrosol (HT), one of the major polyphenols present in olive oil, is known to possess a high antioxidant capacity. The aim of the present study was to investigate dose dependent (0, 1, 10 and 100 mg/kg) alterations in the metabolism of HT in rats since it has been reported that metabolites may contribute to biological effects. Special attention was paid to the activation of the semiquinone quinone oxidative cycle and the formation of adducts with potential deleterious effects. Thus, we developed a novel analytical methodology to monitor the in vivo formation of the HT mercapturate, N-acetyl-5-S-cysteinyl-hydroxytyrosol in urine samples. Biomarkers of hepatic and renal toxicity were ev…
Interrelationship between demethylation of p-nitroanisole and conjugation of p-nitrophenol in rat liver
1973
The metabolism of p-nitroanisole (pNA) and p-nitrophenol (pNP) was studied in isolated rat livers perfused with a hemoglobin-free medium. The activity and viability of the surviving organ was tested by recording pH, “arterial” and “venous” oxygen tension as well as the disappearance of added pNP. pNA is converted to its primary metabolite pNP which, in turn, is excreted into the perfusion medium as conjugates. The coordination of pNA oxidation and the conjugation reactions of pNP were investigated. When 50 μM pNA is added as substrate 0.4±0.1 nmoles×ml−1×(g liver)−1 are excreted as pNP-glucuronide and 3.5±0.2 nmoles×ml−1×(g liver)−1 as the sulphate within 90 min. When pNP itself (50 μM) is …
Characterization of thyroid hormone sulfotransferases
1998
Sulfation is an intriguing pathway of thyroid hormone metabolism since it facilitates the degradation of the hormone by the type I deiodinase (D1). This study reports the preliminary characterization of iodothyronine sulfotransferase activities of rat and human liver cytosol and recombinant rSULT1C1 and hSULT1A1 isoenzymes. All these enzyme preparations catalyzed the sulfation of--in decreasing order of efficiency--3,3'-diiodothyronine (3,3'-T2)3,3',5-triiodothyronine (T3) approximately 3,3',5'-triiodothyronine (rT3)thyroxine (T4). 3,3'-T2 sulfotransferase activity was found to be higher in male than in female rat liver, which has also been shown by others for the expression of rSULT1A1 and…
Gut and microbial resveratrol metabolite profiling after moderate long-term consumption of red wine versus dealcoholized red wine in humans by an opt…
2012
Resveratrol exerts a variety of biological and pharmacological activities, which are observed despite its extremely low bioavailability and rapid clearance from the circulation due to extensive sulfation and glucuronidation in the intestine and liver. In order to more accurately quantify all known resveratrol metabolites, a sensitive and optimized analytical assay was developed and validated by pure standards. Methodology improvements aimed to the chromatographic detection of disulfates and sulfoglucuronides, improving resolution of sulfates, by using a buffered solution, with recovery values of resveratrol and its metabolites, even of sulfates, of 99%. The adapted methodology was then appl…
Sulphation and Hydrolysis Improvements of Bioactivities, and Immuno-Modulatory Properties of Edible Amanita hemibapha Subspecies javanica (Corner and…
2021
In this study, the mucilage polysaccharide (MP) from Amanita hemibapha subspecies javanica was prepared by hot water extraction and ethanol precipitation and then fractionated using anion-exchange chromatography equipped with a DEAE Sepharose fast flow column. The most immune-enhancing polysaccharide fraction 2 (MPF2) was subjected to a structural modification such as hydrolysis or over-sulphation. The sulphate and molecular weight (Mw) of over-sulphated (OS1-3) and hydrolysed (HS1-3) derivatives of MPF2 differed between 9.85% and 14.2% and 32.8 and 88.1 × 103 g/mol, respectively. Further, the immune-enhancing properties of MPF2 and its derivatives were tested on RAW264.7 and NK cells throu…
Evaluation of the enantioselective binding of imazalil to human serum albumin by capillary electrophoresis
2015
In this work, a methodology for the evaluation of enantioselective binding of imazalil (IMA) enantiomers to human serum albumin (HSA) that does not require the separation of free and bound to HSA fractions is developed. This methodology comprises the incubation of IMA–HSA designed mixtures for 30 min directly in the capillary electrophoresis system and the subsequent direct injection and chiral separation of IMA employing highly sulfated β-cyclodextrin as chiral selector and the complete filling technique. Two mathematical approaches were used to estimate apparent affinity constants (K1), protein binding and enantioselectivity (ES) for both enantiomers of IMA. Moderate enantioselective bind…
Sulfotransferase-mediated activation of mutagens studied using heterologous expression systems
1998
Abstract Sulfation is a common final step in the biotransformation of xenobiotics and is traditionally associated with inactivation. However, the sulfate group is electron-withdrawing and may be cleaved off heterolytically in some molecules leading to electrophilic cations which may form adducts with DNA and other important cellular structures. Since endogenous sulfotransferases do not appear to be expressed in indicator cells of standard mutagenicity tests, rat and human sulfotransferases have been stably expressed in his−Salmonella typhimurium strain TA1538 and Chinese hamster V79 cells. Using these recombinant indicator cells, sulfotransferase-dependent genotoxic activities were detected…