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Ammonium Citrate (ammonium + citrate)
Kinds of Ammonium Citrate Selected AbstractsDirect determination of gentamicin components by capillary electrophoresis with potential gradient detectionELECTROPHORESIS, Issue 1 2005LingLing Yuan Abstract A simple and fast method was developed to determine non-UV active compounds directly without derivatization. The usefulness of the method was demonstrated by detecting the major components in aminoglycoside antibiotic mixtures using capillary zone electrophoresis with potential gradient detection. Under optimized separation conditions (0.2 mM cetyltrimethylammonium bromide (CTAB), 1 mM ammonium citrate, pH 3.5), gentamicin was separated into three major peaks (C1, C1a, and C2+C2a) within 15 min. This method showed better sensitivity than other capillary electrophoresis (CE) methods for determining underivatized gentamicin. The linear range was from 10 to 500 ppm. Because of its good repeatability and simplicity, this new method could be a good alternative for the current assays given by US Pharmacopoeia and European Pharmacopoeia. [source] Iron regulatory protein-independent regulation of ferritin synthesis by nitrogen monoxideFEBS JOURNAL, Issue 16 2006Marc Mikhael The discovery of iron-responsive elements (IREs), along with the identification of iron regulatory proteins (IRP1, IRP2), has provided a molecular basis for our current understanding of the remarkable post-transcriptional regulation of intracellular iron homeostasis. In iron-depleted conditions, IRPs bind to IREs present in the 5,-UTR of ferritin mRNA and the 3,-UTR of transferrin receptor (TfR) mRNA. Such binding blocks the translation of ferritin, the iron storage protein, and stabilizes TfR mRNA, whereas the opposite scenario develops when iron in the intracellular transit pool is plentiful. Nitrogen monoxide (commonly designated nitric oxide; NO), a gaseous molecule involved in numerous functions, is known to affect cellular iron metabolism via the IRP/IRE system. We previously demonstrated that the oxidized form of NO, NO+, causes IRP2 degradation that is associated with an increase in ferritin synthesis [Kim, S & Ponka, P (2002) Proc Natl Acad Sci USA99, 12214,12219]. Here we report that sodium nitroprusside (SNP), an NO+ donor, causes a dramatic and rapid increase in ferritin synthesis that initially occurs without changes in the RNA-binding activities of IRPs. Moreover, we demonstrate that the translational efficiency of ferritin mRNA is significantly higher in cells treated with SNP compared with those incubated with ferric ammonium citrate, an iron donor. Importantly, we also provide definitive evidence that the iron moiety of SNP is not responsible for such changes. These results indicate that SNP-mediated increase in ferritin synthesis is, in part, due to an IRP-independent and NO+ -dependent post-transcriptional, regulatory mechanism. [source] Different combinations of salts affect the growth and bacteriocin production by Lactobacillus salivarius CRL 1328JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2010María Silvina Juárez Tomás Abstract BACKGROUND: The culture medium for optimal growth of vaginal Lactobacillus salivarius CRL 1328 is different from that for optimal bacteriocin production. To simultaneously obtain high amount of biomass and bacteriocin of this microorganism, the effects of different basal culture media and salts on both responses were evaluated. The study was performed by using a complete factorial experimental design 26, with central points. Sixty-four different growth media, which resulted from the combinations of two basal culture media and two concentrations of five salts (ammonium citrate, sodium acetate, MgSO4, MnSO4, and K2HPO4) were assayed. RESULTS: Only the addition of MnSO4 to each culture medium significantly stimulated the growth of L. salivarius. The presence of sodium acetate or MgSO4 stimulated the bacteriocin production, while MnSO4 and K2HPO4 exerted an inhibitory effect. However, the simultaneous addition of MnSO4 and sodium acetate to both basal culture media allowed high bacteriocin levels to be reached, attenuating the inhibitory effect of Mn2+. CONCLUSIONS: The application of a complete experimental design contributed to simultaneous optimization of the biomass and bacteriocin production of L. salivarius CRL 1328. The results obtained are potentially applicable to the technological production of probiotic bacteria and antagonistic substance to be included in a probiotic pharmaceutical product. Copyright © 2009 Society of Chemical Industry [source] Divalent metal transporter 1 up-regulation is involved in the 6-hydroxydopamine-induced ferrous iron influxJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2007Ning Song Abstract The reasons underlying the high iron content found in the substantia nigra (SN) of Parkinson's disease (PD) are largely unknown. We suppose, based on our previous studies, that the newly discovered iron transporter divalent metal transporter 1 (DMT1) might be involved in this SN iron accumulation process. To investigate this, we first observed the cellular expression of DMT1 in rat SN, both with the iron response element (+IRE) and without the IRE (,IRE) forms. The results showed that both forms of DMT1 were expressed on neurons, astrocytes, and microglia but not on oligodendrocytes. We further observed the relationship between the increased iron influx and DMT1 expression in 6-hydroxydopamine (6-OHDA)-treated C6 cells. 6-OHDA (10 ,mol/liter) caused a significant increase in ferrous iron influx, with the increased expression of DMT1+IRE, both in protein and in mRNA levels, whereas no change was observed for DMT1,IRE. To clarify further that the increased expression of DMT1 was not due to the increased intracellular iron content, C6 cells were overloaded with ferric ammonium citrate (100 ,g/ml). Decreased expression of both forms of DMT1 was observed. Our data suggest that DMT1 is highly expressed in rat SN in a cell-specific manner. Increased DMT1+IRE expression is the mechanism behind ferrous iron influx induced by 6-OHDA treatment in C6 cells. This may give some evidence for the involvement of DMT1 in the iron accumulation in PD. © 2007 Wiley-Liss, Inc. [source] Curcumin reduces the toxic effects of iron loading in rat liver epithelial cellsLIVER INTERNATIONAL, Issue 1 2009Donald J. Messner Abstract Background/Aims: Iron overload can cause liver toxicity and increase the risk of liver failure or hepatocellular carcinoma in humans. Curcumin (diferuloylmethane), a component of the food spice turmeric, has antioxidant, iron binding and hepatoprotective properties. The aim of this study was to quantify its effects on iron overload and the resulting downstream toxic effects in cultured T51B rat liver epithelial cells. Methods: T51B cells were loaded with ferric ammonium citrate (FAC) with or without the iron delivery agent 8-hydroxyquinoline. Cytotoxicity was measured by methylthiazolyldiphenyl-tetrazolium bromide assay. Iron uptake and iron bioavailability were documented by chemical assay, quench of calcein fluorescence and ferritin induction. Reactive oxygen species (ROS) were measured by a fluorescence assay using 2,,7,-dichlorodihydrofluorescein diacetate. Oxidative stress signalling to jnk, c-jun and p38 was measured by a Western blot with phospho-specific antibodies. Results: Curcumin bound iron, but did not block iron uptake or bioavailability in T51B cells given FAC. However, it reduced cytotoxicity, blocked the generation of ROS and eliminated signalling to cellular stress pathways caused by iron. Inhibition was observed over a wide range of FAC concentrations (50,500 ,M), with an apparent IC50 in all cases between 5 and 10 ,M curcumin. In contrast, desferoxamine blocked both iron uptake and toxic effects of iron at concentrations that depended on the FAC concentration. The effects of curcumin also differed from those of ,-tocopherol, which did not bind iron and was less effective at blocking iron-stimulated ROS generation. Conclusions: Curcumin reduced iron-dependent oxidative stress and iron toxicity in T51B cells without blocking iron uptake. [source] Crystallization and preliminary X-ray analysis of the chemokine-binding protein from orf virus (Poxviridae)ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Rafael Miguez Couñago The parapoxvirus orf virus (ORFV) encodes a chemokine-binding protein (CBP) that functions to downregulate the host's immune response at the site of infection by blocking the chemokine-induced recruitment of immune cells. In order to shed light on the structural determinants of CBP,chemokine binding, ORFV CBP was crystallized as part of an ongoing structure,function study on this protein. ORFV CBP crystals were obtained by the sitting-drop vapour-diffusion technique using ammonium citrate as a precipitant. The crystal quality was greatly improved through the addition of small-molecule additives to the crystallization mother liquor. ORFV CBP crystals diffracted X-rays to 2.50,Å resolution and belonged to the hexagonal space group P6122 or its enantiomorph P6522, with unit-cell parameters a = b = 75.62, c = 282.49,Å, , = 90, , = 90, , = 120°. [source] Improved Fermentation Processes for NS0 Cell Lines Expressing Human Antibodies and Glutamine SynthetaseBIOTECHNOLOGY PROGRESS, Issue 1 2003Jonathan Dempsey To meet the increasing requirement for therapeutic antibodies to conduct clinical trials, an enhanced culture medium and fed-batch process was developed for GS-NS0 cell lines. This process was shown to produce high concentrations of monoclonal antibodies for several cell lines expressing different antibodies. Cells were adapted to growth in a glutamine- and serum-free medium containing bovine serum albumin (BSA), cholesterol, and transferrin. A number of amino acids were found to be depleted during cell culture. The concentrations of these amino acids were increased, and further cell culture analyses were performed. This process of cell growth and analysis was repeated over multiple cycles until no depletion was detected. This resulted in an amino acid supplement that was shown to be generic and enhanced antibody productivity up to 5-fold for the three cell lines tested. Transferrin was replaced using tropolone, a lipophilic iron chelator and ferric ammonium citrate. Cell growth was equivalent to that in transferrin-containing medium over the wide ranges tested. A concentrated feed solution, based on the amino acid supplement and the components of the serum-and protein-free supplements, was formulated. Addition of this feed in response to metabolic requirements resulted in a harvest titer a further 2-fold higher than the enhanced culture medium. Harvest antibody titers of up to 600 mg/L were achieved for three cell lines expressing different antibodies, representing an increase of 10-fold over the starting concentrations. [source] Electrodeposition, Structure and Corrosion Resistance of Nanocrystalline Ni-W AlloyCHINESE JOURNAL OF CHEMISTRY, Issue 3 2004Fang-Zu Yang Abstract Ni,W alloy was electrodeposited from the electrolyte solution containing sodium tungstate, nickel sulfate and ammonium citrate. The electrodeposition, heat treatment, structure, surface morphology and corrosion resistance in w=0.03 NaCl solution, of Ni,W alloys were studied by means of DSC, XRD, SEM and electrochemical techniques. The results showed that the obtained Ni,W alloy electrodeposit with W weight content (ww=0.471) was presented in more typical nanocrystalline. After heat treatment at 400 C for 1 h, the phase structure of the deposits was not obviously changed whereas the agglomerate for the reunion of tiny grains on deposit surface caused the granule in a more smooth morphology, the microhardness was slightly increased and the corrosion resistance was enhanced. [source] | |||||||||||||