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BACKGROUND: Chondroitin and glucosamine sulphates (CGS) are considered structure-modifying drugs and have been studied in the prevention, delay or reversal of structural morphological changes in joints caused by osteoarthritis. OBJECTIVE: The aim of the present study was to investigate the action of CGS on the progression of chemically induced osteoarthritis in the temporomandibular joint (TMJ) of rabbits by evaluating the serum levels of tumour necrosis factor (TNF-α) and collagen in the articular discs. MATERIALS AND METHODS: A sample of 36 male rabbits was divided into three groups: control (CG), osteoarthritis (OG) and treatment (TG). The disease was induced by intra-articular injection of sodium monoiodoacetate (10 mg/mL) in the OG and TG groups bilaterally. After 10 days, the TG animals received subcutaneous injection of chondroitin sulphates and glucosamine (7.5 mg/kg) and the OG and CG received saline solution (50 µL). Euthanasia times were subdivided into 40 and 100 days. Collagen quantification was performed by biochemical and histological analysis and for the quantification of serum levels of TNF-α, an enzyme immunoassay was used. RESULTS: The TG showed an increase in the collagen area of the articular disc when compared to the CG and the OG. The increase collagen concentration in the discs did not show a statistically significant difference between the groups. Post-treatment TNF-α levels were significantly lower in TG compared to OG. CONCLUSIONS: The results indicate that CGS treatment delayed the degeneration of the collagen in the TMJ articular disc and reduced serum TNF-α levels, indicating a preventive effect on OA progression.

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Glucosamine-chitosan synthesized by the Maillard reaction was combined with montmorillonite to obtain a nanohybrid composite to immobilize horseradish peroxidase. The material combines the advantageous properties of clay with those of the chitosan derivative; has improved water solubility and reduced molecular weight and viscosity; involves an eco-friendly synthesis; and exhibits ion exchange capacity, good adhesiveness, and a large specific surface area for enzyme adsorption. The physicochemical characteristics of the composite were analyzed by infrared spectroscopy and X-ray diffraction to determine clay-polycation interactions. The electrochemical response of the different polyphenols to glassy carbon electrodes modified with the composite was evaluated by cyclic voltammetry. The sensitivity and detection limit values obtained with the biosensor toward hydroquinone, chlorogenic acid, catechol, and resorcinol are (1.6 ± 0.2) × 102 µA mM-1 and (74 ± 8) nM; (1.2 ± 0.1) × 102 µA mM-1 and (26 ± 3) nM; (16 ± 2) µA mM-1 and (0.74 ± 0.09) µM; and (3.7± 0.3) µA mM-1 and (3.3 ± 0.2) µM, respectively. The biosensor was applied to quantify polyphenols in pennyroyal and lemon verbena extracts.

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The bacterial genus Rhodococcus comprises organisms performing oleaginous behaviors under certain growth conditions and ratios of carbon and nitrogen availability. Rhodococci are outstanding producers of biofuel precursors, where lipid and glycogen metabolisms are closely related. Thus, a better understanding of rhodococcal carbon partitioning requires identifying catalytic steps redirecting sugar moieties to storage molecules. Here, we analyzed two GT4 glycosyl-transferases from Rhodococcus jostii (RjoGlgAb and RjoGlgAc) annotated as α-glucan-α-1,4-glucosyl transferases, putatively involved in glycogen synthesis. Both enzymes were produced in Escherichia coli cells, purified to homogeneity, and kinetically characterized. RjoGlgAb and RjoGlgAc presented the "canonical" glycogen synthase activity and were actives as maltose-1P synthases, although to a different extent. Then, RjoGlgAc is a homologous enzyme to the mycobacterial GlgM, with similar kinetic behavior and glucosyl-donor preference. RjoGlgAc was two orders of magnitude more efficient to glucosylate glucose-1P than glycogen, also using glucosamine-1P as a catalytically efficient aglycon. Instead, RjoGlgAb exhibited both activities with similar kinetic efficiency and preference for short-branched α-1,4-glucans. Curiously, RjoGlgAb presented a super-oligomeric conformation (higher than 15 subunits), representing a novel enzyme with a unique structure-to-function relationship. Kinetic results presented herein constitute a hint to infer on polysaccharides biosynthesis in rhodococci from an enzymological point of view.

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Purpose:Tau hyperphosphorylation is a modification frequently observed after brain ischemia which has been related to the aggregation of this protein, with subsequent cytoskeletal damage, and cellular toxicity. The present study tests the hypothesis of using glucosamine, an agent that increases protein O-GlcNAcylation, to decrease the levels of phosphorylation in Tau during ischemia-reperfusion.Material and methods: Transient focal ischemia was artificially induced in male Wistar rats by occlusion of the middle cerebral artery (MCAO) with an intraluminal monofilament. A single dose of intraperitoneal glucosamine of 200 mg/kg diluted in normal saline (SSN) was administered 60 min before ischemia. Histological brain sections were processed using indirect immunofluorescence with primary antibodies (anti-O-GlcNAc and anti pTau-ser 396). The Image J software was used to calculate the immunofluorescence signal intensity.Results: The phosphorylation of Tau at the serine residue 396 had a significant decrease with the administration of glucosamine during ischemia-reperfusion compared with the administration of placebo.Conclusions: These results show that glucosamine can reduce the phosphorylation levels of Tau in rodents subjected to ischemia and cerebral reperfusion, which implies a neuroprotective role of glucosamine.

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The cell wall (CW) of fungi exhibits a complex structure and a characteristic chemical composition consisting almost entirely of interacting crystalline and amorphous polysaccharides. These are synthesized by a number of sugar polymerases and depolymerases encoded by a high proportion of the fungal genome (for instance, 20% in Saccharomyces cerevisiae). These enzymes act in an exquisitely coordinated process to assemble the tridimensional and the functional structure of the wall. Apart from playing a critical role in morphogenesis, cell protection, viability and pathogenesis, the CW represents a potential target for antifungals as most of its constituents do not exist in humans. Chitin, ß-glucans and cellulose are the most frequent crystalline polymers found in the fungal CW. The hexosamine biosynthesis pathway (HBP) is critical for CW elaboration. Also known as the Leloir pathway, this pathway ends with the formation of UDP-N-GlcNAc after four enzymatic steps that start with fructose-6-phosphate and L-glutamine in a short deviation of glycolysis. This activated aminosugar is used for the synthesis of a large variety of biomacromolecules in a vast number of organisms including bacteria, fungi, insects, crustaceans and mammalian cells. The first reaction of the HBP is catalyzed by GlcN-6-P synthase (L-glutamine:D-fructose-6-phosphate amidotransferase; EC 2.6.1.16), a critical enzyme that has been considered as a potential target for antifungals. The enzyme regulates the amount of cell UDP-N-GlcNAc and in eukaryotes is feedback inhibited by the activated aminosugar and other factors. The native and recombinant forms of GlcN-6-P synthase has been purified and characterized from both prokaryotic and eukaryotic organisms and demonstrated its critical role in CW remodeling and morphogenesis after exposure of some fungi to agents that stress the cell surface by interacting with wall polymers. This review deals with some of the cell compensatory responses of fungi to wall damage induced by Congo Red and Calcofluor White.

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The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells.(AU)

Investigou-se o efeito de métodos para remover o conteúdo de proteínas nas propriedades do cloridrato de glucosamina das conchas de camarão de pernas brancas (Litopenaeus vannamei) e camarão de tigre preto (Penaeus monodon). A quitina das cascas de camarão foi obtida por desmineralização em HCl a 6% por 12 h, desproteinização por dois métodos diferentes (primeiro grupo embebido em NaOH a 8% por 36 h e segundo grupo tratado na enzima Alcalase na concentração de 0,2% por 36 h). Duas amostras de grupo foram convertidas em cloridrato de glucosamina por imersão em solução de 12M HCl por 5 h a 85 °C. Os resultados das análises de FTIR, solubilidade e rendimento de recuperação mostraram que os métodos de desproteinização não afetaram significativamente as propriedades do cloridrato de glucosamina. No entanto, o cloridrato de glucosamina de cascas de camarão de pernas brancas continha maior rendimento e solubilidade de recuperação do que as cascas de camarão tigre preto.(AU)

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The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells.

Investigou-se o efeito de métodos para remover o conteúdo de proteínas nas propriedades do cloridrato de glucosamina das conchas de camarão de pernas brancas (Litopenaeus vannamei) e camarão de tigre preto (Penaeus monodon). A quitina das cascas de camarão foi obtida por desmineralização em HCl a 6% por 12 h, desproteinização por dois métodos diferentes (primeiro grupo embebido em NaOH a 8% por 36 h e segundo grupo tratado na enzima Alcalase na concentração de 0,2% por 36 h). Duas amostras de grupo foram convertidas em cloridrato de glucosamina por imersão em solução de 12M HCl por 5 h a 85 °C. Os resultados das análises de FTIR, solubilidade e rendimento de recuperação mostraram que os métodos de desproteinização não afetaram significativamente as propriedades do cloridrato de glucosamina. No entanto, o cloridrato de glucosamina de cascas de camarão de pernas brancas continha maior rendimento e solubilidade de recuperação do que as cascas de camarão tigre preto.

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Abstract The objective of the present study is to develop and validate a simple, selective and accurate hydrophilic interaction liquid chromatography - a high performance liquid chromatography incorporating an evaporative light scattering detector (HILIC-HPLC-ELSD) method for simultaneously determining glucosamine hydrochloride and chondroitin sulfate in dietary supplements. The chromatographic separation was carried out on a ZIC-HILIC column (150 mm x 4.6 mm x 5µm) in isocratic system mode with a mobile phase of acetonitrile, 30 mM ammonium formate and water (77:20:3, v/v/v) at pH 4.5, a column temperature of 35°C, a flow rate of 1 mL.min-1, and an injection volume of 5 µL. An evaporative light scattering (ELS) detector was used. Effective separation was achieved by means of analyte resolution of more than 1.5 with an analysis run time of approximately 20 minutes. The linearity of glucosamine hydrochloride and chondroitin sulfate ranged from 0.4 to 2.5 mg.mL-1. The limits of the detection and quantification of glucosamine hydrochloride were 20 and 80 mg.mL-1 respectively, while for chondroitin sulfate they were 80 and 400 mg.mL-1. All validation parameters satisfied the acceptance criteria in accordance with International Conference on Harmonisation (ICH) guidelines. The method was successfully applied to the assay of commercial dietary supplement samples

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ABSTRACT: The effect of methods to remove protein content on the properties of glucosamine hydrochloride from the shells of white leg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon) was investigated. Chitin from shrimp shells was obtained by demineralization in 6% HCl for 12h, deproteinization by two different methods (first group soaked in 8% NaOH for 36h and second group treated in Alcalase enzyme at the concentration of 0.2% for 36h). Two group samples were converted to glucosamine hydrochloride by soaking in 36.76% HCl solution for 5h at 85 °C. The results of fourier transform infrared spectroscopy (FTIR), solubility and recovery yield analysis showed that deproteinization methods did not significantly affect the properties of glucosamine hydrochloride. However, glucosamine hydrochloride from white leg shrimp shells contained higher recovery yield and solubility than black tiger shrimp shells.

RESUMO: Investigou-se o efeito de métodos para remover o conteúdo de proteínas nas propriedades do cloridrato de glucosamina das conchas de camarão de pernas brancas (Litopenaeus vannamei) e camarão de tigre preto (Penaeus monodon). A quitina das cascas de camarão foi obtida por desmineralização em HCl a 6% por 12 h, desproteinização por dois métodos diferentes (primeiro grupo embebido em NaOH a 8% por 36 h e segundo grupo tratado na enzima Alcalase na concentração de 0,2% por 36 h). Duas amostras de grupo foram convertidas em cloridrato de glucosamina por imersão em solução de 12M HCl por 5 h a 85 °C. Os resultados das análises de FTIR, solubilidade e rendimento de recuperação mostraram que os métodos de desproteinização não afetaram significativamente as propriedades do cloridrato de glucosamina. No entanto, o cloridrato de glucosamina de cascas de camarão de pernas brancas continha maior rendimento e solubilidade de recuperação do que as cascas de camarão tigre preto.

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GNPDA2 has been associated with human obesity and type-2 diabetes by using a GWAS approach. GNPDA2 is an enzyme involved in the hexosamine biosynthesis pathway, which is known to be important for nutrient sensing in various organism. Its counter enzyme, GFAT, has previously been shown to be important to the development of insulin resistance in diabetes. The implication of GNPDA2 and GFAT in metabolism is scarce and the effect of both enzymes over appetite and glucose homeostasis is unknown. Aim: Identify the role of GNPDA2 and GFAT in nutrient sensing circuits of the CNS that are important for the regulation of both appetite and glucose homeostasis. Methods: Using Long Evans rats, we administered either a GNPDA2 or GFAT antagonist or vehicle in i3vt. Key Findings: GNPDA2 is highly expressed in hypothalamus and adipose tissue, followed by muscle and liver. GNPDA2 is expressed in different hypothalamic nuclei (ARC, DMH, LHA, PVN). GNPDA2 is downregulated in hypothalamus under diet-induced obesity (as previously described), but GFAT expression does not change. Moreover, i3vt infusion of GNPDA2 or GFAT inhibitor resulted in increased c-Fos in areas related to appetite and glucose homeostasis control as PVN and DMH and to a lesser extent in the LHA and ARC. Central inhibition of GNPDA2 does not alter either acute food intake or body weight; however, GFAT inhibition diminished appetite and body weight due to visceral illness. In addition, central administration of the GNPDA2 antagonist, prior to an intraperitoneal glucose tolerance test, resulted in glucose intolerance in comparison to vehicle without altering insulin levels. Significance: These results suggest that central GNPDA2 does not control appetite, but regulates glucose homeostasis.