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Soluble Fraction (soluble + fraction)
Selected AbstractsSwelling behavior of pH- and temperature-sensitive copolymers containing 2-hydroxy-ethyl methacrylate and N -vinyl-2-pyrrolidone crosslinked with new crosslinkersPOLYMER INTERNATIONAL, Issue 11 2004Prof. Ayman M Atta Abstract Copolymers of 2-hydroxyethyl methacrylate (HEMA) and N -vinyl-2-pyrrolidone (VP) and homopolymers of HEMA and VP were crosslinked in the presence of different mol% of melamine trimethacrylamide (MMAm) and melamine triacrylamide (MAAm) as crosslinkers by bulk radical polymerization. The resultant xerogels were characterized by extracting the soluble fractions and measuring the equilibrium water content. Lower critical solution transition temperatures (LCST) were measured by DSC. The properties of crosslinked HEMA and VP copolymers, VP and HEMA series were evaluated in terms of compositional drift of polymerization, heterogeneous crosslinking, and chemical structure of the relevant components. Soluble fractions of the crosslinked networks were reduced by varying the MAAm and MMAm concentrations. The influence of environmental conditions such as temperature and pH on the swelling behavior of these polymeric gels was investigated. The swelling behaviors of the resulting gels show pH sensitivity. This behavior is explained on the basis that amide groups of VP or crosslinkers could be hydrolyzed to form negatively charged carboxylate ion groups in the produced networks in response to an external pH variation. Copyright © 2004 Society of Chemical Industry [source] Role of myosin II activity and the regulation of myosin light chain phosphorylation in astrocytomasCYTOSKELETON, Issue 1 2008Bodour Salhia Abstract The generation of contractile force mediated by actin-myosin interactions is essential for cell motility. Myosin activity is promoted by phosphorylation of myosin light chain (MLC). MLC phosphorylation in large part is controlled by kinases that are effectors of Rho family GTPases. Accordingly, in this study we examined the effects of ROCK and Rac1 inhibition on MLC phosphorylation in astrocytoma cells. We found that low concentrations of the ROCK inhibitor Y27632 increased the phosphorylation state of the Triton X-100 soluble fraction of MLC, whereas higher concentrations of Y27632 decreased soluble phospho-MLC. These effects of Y27632 were dependent on Rac1. The soluble form of phospho-MLC comprises about 10% of total phospho-MLC in control cells. Interestingly, ROCK inhibition led to a decrease in the phosphorylation state of total MLC, whereas Rac1 inhibition had little effect. Thus, the soluble form of MLC is differentially regulated by ROCK and Rac1 compared with MLC examined in a total cell extract. We also observed that astrocytoma migration is stimulated by low concentrations of the myosin II inhibitor blebbistatin. However, higher concentrations of blebbistatin inhibit migration leading us to believe that migration has a biphasic dependence on myosin II activity. Taken together, our data show that modulation of myosin II activity is important in determining optimal astrocytoma migration. In addition, these findings suggest that there are at least two populations of MLC that are differentially regulated. Cell Motil. Cytoskeleton 2008. © 2007 Wiley-Liss, Inc. [source] Proteome analysis of human liver tumor tissue by two-dimensional gel electrophoresis and matrixassisted laser desorption/ionization-mass spectrometry for identification of disease-related proteinsELECTROPHORESIS, Issue 24 2002Jina Kim Abstract Hepatocellular carcinoma (HCC) is a common malignancy worldwide and is a leading cause of death. To contribute to the development and improvement of molecular markers for diagnostics and prognostics and of therapeutic targets for the disease, we have largely expanded the currently available human liver tissue maps and studied the differential expression of proteins in normal and cancer tissues. Reference two-dimensional electrophoresis (2-DE) maps of human liver tumor tissue include labeled 2-DE images for total homogenate and soluble fraction separated on pH 3,10 gels, and also images for soluble fraction separated on pH 4,7 and pH 6,9 gels for a more detailed map. Proteins were separated in the first dimension by isoelectric focusing on immobilized pH gradient (IPG) strips, and by 7.5,17.5% gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels in the second dimension. Protein identification was done by peptide mass fingerprinting with delayed extraction-matrix assisted laser desorption/ionization-time of flight-mass spectrometry (DE-MALDI-TOF-MS). In total, 212 protein spots (117 spots in pH 4,7 map and 95 spots in pH 6,9) corresponding to 127 different polypeptide chains were identified. In the next step, we analyzed the differential protein expression of liver tumor samples, to find out candidates for liver cancer-associated proteins. Matched pairs of tissues from 11 liver cancer patients were analyzed for their 2-DE profiles. Protein expression was comparatively analyzed by use of image analysis software. Proteins whose expression levels were different by more than three-fold in at least 30% (four) of the patients were further analyzed. Numbers of protein spots overexpressed or underexpressed in tumor tissues as compared with nontumorous regions were 9 and 28, respectively. Among these 37 spots, 1 overexpressed and 15 underexpressed spots, corresponding to 11 proteins, were identified. The physiological significance of the differential expressions is discussed. [source] Water soluble fraction of solar-simulated light-exposed crude oil generates phosphorylation of histone H2AX in human skin cells under UVA exposureENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 6 2007Yuko Ibuki Abstract Crude oil contains compounds, which have toxic and cancer-causing properties to humans. The oil spilled in environments is usually exposed to sunlight; however, the toxicity of sunlight-exposed oil is poorly understood. In this study, we found that the water soluble fraction (WSF) of crude oil irradiated with solar-simulated light (SSL) generated phosphorylation of histone H2AX (,-H2AX) in human skin cells under UVA irradiation, which was due to the formation of DNA double strand breaks (DSBs). Crude oil was exposed to SSL for ,7 days. The WSF obtained from unexposed crude oil showed no toxicity, whereas the WSF obtained from crude oil pre-exposed to SSL induced acute cell death on exposure to UVA irradiation (induction of phototoxicity), which was more remarkable in human skin fibroblasts than human skin keratinocytes. ,-H2AX was detected in both cell lines immediately after treatment with the WSF plus UVA. Interestingly, ,-H2AX was detectable even at low SSL- and UVA-doses, which induced no cytotoxicity. The WSF of crude oil irradiated with SSL, generated DSBs under UVA irradiation, which were detected by biased sinusoidal field gel electrophoresis. This was confirmed using xrs-5 cells isolated from CHO-K1 cells, which are deficient in a repair enzyme for DSBs; the WSF plus UVA induced a more dramatic decrease in survival in xrs-5 cells than CHO-K1 cells. These findings demonstrate that exposure of crude oil to sunlight makes the WSF phototoxic, generating DSBs accompanying the appearance of ,-H2AX in human skin cells. Environ. Mol. Mutagen., 2007. © 2007 Wiley-Liss, Inc. [source] Transfer and efflux of cadmium and silver in marine snails and fish fed pre-exposed mussel preyENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2007Ma-Shan Cheung Abstract Subcellular metal distribution may play an important role in the bioaccumulation and trophic transfer of metals in marine food chains. In the present study, we preexposed the green mussel Perna viridis to Ag and Cd and quantified their trophic transfer efficiencies to two predators (whelks [Thais clavigera] and fish [Terapon jarbua]). For the mussels, more Ag was distributed in the metal-rich granule (MRG) fraction following Ag exposure, and more Cd was distributed in the metallothionein-like protein following Cd exposure. In addition, Cd was mainly bound with the proteins having a molecular size of approximately 20 kDa. After being fed with metal-exposed mussels, the assimilation efficiencies of Ag decreased significantly (from 77 to 29,60% in whelks and from 9 to 2% in fish) with an increasing percentage of Ag deposited in the MRG fraction of the prey. In contrast, the assimilation efficiencies of Cd remained comparable (81,85% in whelks and 6,8% in fish), because its partitioning in the soluble fraction of different treatments of the prey was similar. The efflux of Ag and Cd in the two predators was comparable after feeding on preexposed mussel prey. Our results imply that the subcellular distribution of metals in prey may affect the dietary assimilation of metals in predators, but such influence is clearly metal-specific. The present study may lead to a better understanding of metal trophic transfer in different marine food chains. [source] Dynamics of metal subcellular distribution and its relationship with metal uptake in marine musselsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2005Tania Y-T. Abstract We examined the dynamics of subcellular distribution of metals (Cd, Ag, and Zn) in the marine green mussel Perna viridis by partitioning the metals into the insoluble fraction (IF), heat-sensitive proteins (HSP), and metallothionein-like proteins (MTLP) during metal uptake and elimination. Variations in metal uptake and elimination then were correlated with the subcellular distributions of these metals. The IF and HSP were the first ligands to bind with the metals during the dissolved exposure, and more metals were found in the HSP when the metal influx rate was higher. However, to minimize toxicity, metals were redistributed from HSP to MTLP afterwards. The subcellular distribution of metals was dependent of the exposure route in the mussels. During dietary metal exposure, the metals attained equilibrium before they were assimilated and the metal assimilation efficiency was independent of the metal partitioning in different subcellular fractions. During the efflux, metals in the soluble fraction mediated depuration, whereas metals in the insoluble fraction acted as a final storage pool. Redistribution also may occur between the metal-sensitive and inactive pools without significant depuration as a secondary protective mechanism. We further demonstrated that the higher efflux rate of Ag and Cd was related to a higher partitioning in the MTLP and a lower partitioning in the IF. Our study shows that subcellular pools other than MTLP were involved in immediate metal handling in the bivalves. The wide dynamics of subcellular metal distribution suggests that the relevance of individual subcellular fractions is dependent on the exposure pathway. [source] Small intestinal digestibility of microbial and endogenous amino acids in dairy cowsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2001M. Larsen The small intestinal digestibility of microbial amino acids and the apparent re-absorption of endogenous amino acids were estimated in three ruminal, duodenal and ileal fistulated lactating dairy cows. The cows were assigned to a 3 × 3 Latin square and fed diets low in amino acids, composed of straw, starch, molasses and urea. The treatments were three straw to concentrate ratios. The digestibilities and re-absorptions were estimated from duodenal and ileal flows of amino acids from feed, microbial and endogenous sources. The duodenal distribution of amino acids between different origins was determined by the difference method and by the amino acid profile method. The ileal distribution was estimated by a simple method where the feed fraction was estimated by the mobile bag method, the endogenous fraction as the water soluble fraction and the microbial fraction as the rest. In ileal samples, 8.0 ± 1.1, 52.2 ± 2.9 and 39.8 ± 2.6% of total amino acid nitrogen (AAN) were of feed, microbial and endogenous origin, respectively, compared with 5.1 ± 0.9, 61.6 ± 6.6 and 32.7 ± 6.9% in duodenal samples. The small intestinal digestibility of microbial AAN was estimated to be 75.1 ± 1.8% and the apparent re-absorption of endogenous AAN to be 62.3 ± 11.1%. [source] Effect of aroclor 1248 and two pure PCB congeners on phospholipase D activity in rat renal tubular cell culturesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2007Mercedes Fernández Santiago Abstract This paper elucidates the effect of different polychlorinated biphenyls (PCBs) on the phospholipase D (PLD) activity in soluble and particulate fractions of rat renal proximal tubular culture cells. Treatment with Aroclor 1248 (a commercial PCB mixture) caused a marked increase in the activity of PLD in intact renal tubular cells. The PLD activity was increased by Aroclor 1248 in the particulate fraction while the enzyme activity was unaffected in the soluble fraction. This work also shows that PCB 153 (2,2',4,4',5,5'-hexachlorobiphenyl, a di-ortho-substituted nonplanar congener) can increase the activity of PLD only in the particulate fraction. The exposure of cell cultures to PCB 77 (3,3',4,4'-tetrachlorobiphenyl, a non-ortho-substituted planar congener) does not alter PLD activity. These results suggest that PCB effects are structure dependent. Therefore, in order to clarify the molecular mechanism of activation of PLD by PCBs, the contents of immunoreactive PLD were examined by immunoblot analysis. Renal tubular cells expressed a PLD protein of 120 kDa corresponding with the PLD1 mammalian isoform in both the particulate and the soluble fraction. Aroclor 1248, PCB 153, and PCB 77 do not induce changes in the levels of PLD protein. These data indicate that PCBs, particularly nonplanar congeners, increase PLD activity. Moreover, these changes could not be demonstrated in the enzyme content in rat renal tubular cell cultures. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:68,75, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20160 [source] Functional and Thermal Gelation Properties of Squid Mantle Proteins Affected by Chilled and Frozen StorageJOURNAL OF FOOD SCIENCE, Issue 6 2003M.C. Gómez-Guillén ABSTRACT: Fresh squid (Loligo vulgaris) mantles that underwent chilled and frozen storage were studied for their ability to form thermal gels as well as the effects of changes to the functional and chemical properties of the muscle proteins during storage. Assays of protein extractability in 5% NaCl, apparent viscosity, autolytic activity, and SDS-PAGE (of the soluble fraction) were carried out periodically. After 4 d of chilled storage, there was a significant drop in protein functionality that negatively affected the thermal gelation profile. The rate of proteolysis remained very high throughout frozen storage, however functional properties and thermal behavior remained very stable. [source] LC-MSMS identification of Arabidopsis thaliana heat-stable seed proteins: Enriching for LEA-type proteins by acid treatmentJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2007E. Oliveira Abstract Protein identification in systems containing very highly abundant proteins is not always efficient and usually requires previous enrichment or fractionation steps in order to uncover minor proteins. In plant seeds, identification of late embryogenesis abundant (LEA) proteins is often masked by the presence of the large family of storage proteins. LEA-proteins are predicted to play a role in plant stress tolerance. They are highly hydrophilic proteins, generally heat-stable, and correlate with dehydration in seeds or vegetative tissues. In the present work, we analyze the protein composition of heat-stable Arabidopsis thaliana seed extracts after treatment with trichloroacetic acid (TCA). The composition of the proteins that precipitate and those that remain in solution in 3% TCA was analyzed by two different approaches: 1D SDS-PAGE coupled to LC-ESI-MSMS analysis and a gel-free protocol associated with LC-MALDI-MSMS. Our results indicate that treating total heat-soluble extracts with 3% TCA is an effective procedure to remove storage proteins by selective precipitation and this fractionation step provides a soluble fraction highly enriched in Lea-type proteins. The analysis and determination of protein identities in this acid-soluble fraction by MS technology is a suitable system for large-scale identification of Lea-proteins present in seeds. Copyright © 2007 John Wiley & Sons, Ltd. [source] Protective up-regulation of CK2 by mutant huntingtin in cells co-expressing NMDA receptorsJOURNAL OF NEUROCHEMISTRY, Issue 3 2008Mannie M. Y. Fan Abstract Huntington's disease is caused by a polyglutamine expansion in the huntingtin (htt) protein, and previous data indicate that over-activation of NMDA receptors (NMDARs) may be involved in the selective degeneration of cells expressing NR1/NR2B NMDARs. We used KinetworksÔ multi-immunoblotting screens to examine expression of 76 protein kinases, 18 protein phosphatases, 25 heat shock/stress proteins, and 27 apoptosis proteins in human embryonic kidney 293 cells transfected with NR1/NR2B and htt containing 15 (htt-15Q; wild-type) or 138 (htt-138Q; mutant) glutamine repeats. Follow-up experiments revealed several proteins involved in the heat-shock response pathway to be up-regulated in the soluble fraction from cells expressing htt-138Q, including protein phosphatase 5 and cyclin-dependent kinase 5. Increased expression in the soluble fraction of htt-138Q-expressing cells was also noted for the stress- and calcium-activated protein-serine/threonine kinase casein kinase 2, a change which was confirmed in striatal tissue of yeast artificial chromosome transgenic mice expressing full-length mutant htt. Inhibition of casein kinase 2 activity in cultured striatal neurons from these mice significantly exacerbated NMDAR-mediated toxicity, as assessed by labeling of apoptotic nuclei. Our findings are consistent with up-regulation of components of the stress response pathway in the presence of polyglutamine-expanded htt and NR1/NR2B which may reflect an attempt at the cellular level to ameliorate the detrimental effects of mutant htt expression. [source] Effect of lucerne preservation method on the feed value of forageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2009Donato Andueza Abstract BACKGROUND: Natural climatic wilt (NCW) and induced industrial wilt (IIW) are widely used as preservation methods for lucerne. Both of these methods reduce the quality of green forage due to respiration under NCW and heat damage under IIW. We compared the influence of these two preservation methods on nutritive value across a wide range of harvest conditions. RESULTS: Cell wall content and cell wall-linked nitrogen values were higher (P < 0.05) in IIW than NCW. The preservation methods differed significantly (P < 0.05) in terms of soluble fraction, insoluble potentially degradable fraction of dry matter and effective degradability of dry matter. Nitrogen disappearance kinetics showed that the interactions of preservation by cut and preservation by phenological state were significant for the effective degradability of nitrogen. Organic matter digestibility was higher in lucerne preserved by NCW than IIW whereas cell wall digestibility was higher in lucerne preserved by IIW than NCW. Digestible organic matter intake did not differ between preservation methods (P > 0.05). CONCLUSION: Natural climatic wilt forage hay presents similar feed value to the induced industrial wilt alfalfa. Copyright © 2009 Society of Chemical Industry [source] Antioxidant activity of the ethanolic extract from the bark of Chamaecyparis obtusa var. formosanaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2008Palanisamy Marimuthu Abstract BACKGROUND:Chamaecyparis obtusa var. formosana (Taiwan hinoki) is an endemic conifer in Taiwan and the purpose of this study is to evaluate the antioxidant activity of various fractions obtained from the bark of this plant material. The ethanolic extract of the bark was sequentially separated into three fractions, including n -hexane, ethyl acetate and ethanol soluble fractions, by liquid,liquid partition. Then the antioxidant activities of crude extract and three fractions along with 13 subfractions obtained from the ethyl acetate (EA) soluble fraction were tested for several antioxidant assays. RESULTS: The total phenolic content of the samples varied from 27.71 to 102.86 mg GAE g,1 dry weight for fractions, and from 49.94 to 206.46 mg GAE g,1 for subfractions (where GAE is milligrams of gallic acid per gram of extract). The Trolox equivalent antioxidant capacity (TEAC) ranged from 0.15 to 0.26 mmol L,1 Trolox equivalents. The EA soluble fraction was found to be the best antioxidant-rich fraction in terms of DPPH and reducing power assays. With further data analysis it was found that there was a positive correlation between the total phenolic content of extracts and TEAC is R2 = 0.61. CONCLUSION: Results from various antioxidant assays showed that the EA fraction possessed strong antioxidant activity. This would provide additional information about the antioxidant activity of bark extract of this plant species. Copyright © 2008 Society of Chemical Industry [source] Angiotensin converting enzyme inhibition of fish protein hydrolysates prepared from alkaline-aided channel catfish protein isolateJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2007Ann E Theodore Abstract Peptides derived from aquatic animals have been shown to have inhibitory activity against angiotensin converting enzyme (ACE), which is a key enzyme behind elevated blood pressure. In this study a catfish protein isolate was prepared and hydrolyzed to 5%, 15% and 30% degrees of hydrolysis (% DH) and soluble peptides separated from the total hydrolysate. The hydrolysate and its soluble peptide fraction were studied separately. Increased hydrolysis produced smaller peptides, with the smallest peptides remaining in the soluble fraction. Both hydrolysates and its soluble fraction had high ACE inhibition activities, from 70% to 90.6%, depending on fraction and % DH. Results suggested that there is not a simple relationship between average peptide size and extent of % DH and ACE inactivation, but clearly the soluble fraction of the hydrolysate, containing the smallest peptides, is responsible for most of the ACE inhibition activity of the hydrolysate. Hydrolysates prepared from a pure and uniform catfish protein isolate substrate do therefore show a potential for ACE inhibition and may find use as bioactive ingredients. Copyright © 2007 Society of Chemical Industry [source] Cloning and some properties of Japanese pear (Pyrus pyrifolia) polyphenol oxidase, and changes in browning potential during fruit maturation,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2003Makiyo Nishimura Abstract A PCR-amplified genomic DNA fragment encoding Japanese pear (Pyrus pyrifolia) polyphenol oxidase (PPO) was cloned and sequenced. The DNA appears to encode a 66 kDa precursor protein consisting of a 56 kDa mature protein and a 9.5 kDa N-terminal transit peptide. The amino acid sequence showed high homology with apple PPO. The PPO mainly existed as a soluble fraction in cells and was limitedly proteolysed, while the mature form (56 kDa) was detected in plastids. Immature fruits showing high browning potential had high PPO activity and a high level of phenolics, while mature fruits showing little browning had high PPO activity but a low level of phenolics. Copyright © 2003 Society of Chemical Industry [source] In vitro proteolysis of myofibrillar and sarcoplasmic proteins of European sea bass (Dicentrarchus Labrax L) by an endogenous m-calpainJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2002Véronique Verrez-Bagnis Abstract The effects of m-calpain isolated from the skeletal muscle of sea bass on sarcoplasmic and myofibrillar proteins isolated from the same tissue were examined in vitro. Incubation of sarcoplasmic proteins with m-calpain resulted in only a slight decrease (0.7,kDa) in the molecular weight (MW) of a 26.5,kDa protein. Degradation of myofibrils, monitored by quantification of TCA-soluble peptides generated, resulted in the maximum amount of peptides being generated after 1,h of incubation at 25,°C. Noticeable modifications in the SDS-PAGE profile of digested myofibrils were observed, including partial denaturation of myosin heavy chain and the release of tropomyosin, ,69 and ,27,kDa doublet bands and a few polypeptides of MW lower than 20,kDa in the soluble fraction. Examination of the degradation patterns of myofibrillar proteins using Western blotting showed that ,-actinin was partially degraded, with release of native ,-actinin and its fragments from myofibrils, whereas desmin was highly degraded after 2,h of digestion. © 2002 Society of Chemical Industry [source] Organic,Inorganic Interactions in Poly(trimethylene carbonate),Titania HybridsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 21 2009Elisa Cortecchia Abstract Polycarbonate,titania hybrids have been synthesized by a sol,gel reaction, starting from poly(trimethylene carbonate) (PTMC) and titanium isoproproxide in different ratios. PTMC with a given chain length was obtained by ring opening polymerization. FT-IR spectra reveal the presence of TiOC covalent bonds between organic and inorganic phases, and their number increases with increasing inorganic phase content. Solvent extractions show that hybrid soluble fraction contains low PTMC chains with isopropoxide ends, which suggests that TiOC bond formation is mainly promoted by transesterification reactions of isopropyl alcohol onto the polymer chain, catalyzed by Ti compounds. Hybrid thermal properties reflect the combined effect of the decrease of PTMC molecular weight and of bond formation between PTMC and the inorganic network. The nanometric dimension of the TiO2 domains, confirmed by atomic force microscopy, provides optically transparent hybrids. [source] Cationic Polymerization of 2-Vinylthiophene by Chloroarylmethanes as Surface Initiators on Silica and Consecutive Hydride Abstraction by AcceptorsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 12 2004Susanne Höhne Abstract Summary: 2-Vinylthiophene (2-VT) has been cationically polymerized using chloroarylmethane derivatives as the surface polymerization initiator on silica. By applying this procedure a soluble fraction of poly(vinylthiophene) (PVT) and PVT/silica composites can be simultaneously synthesized. The mass balance of the products (soluble fraction and hybrid particle fraction) depends significantly on temperature and 2-VT/silica ratio. The hydride abstraction reaction of PVT both in solution and immobilized on silica particle surface has been studied using 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ), tetrachloro-1,4-quinone (chloranile,=,ClA) and triphenylmethylium as reagents. The transformation process of PVT towards conjugated polymers has been studied with UV-vis spectroscopy and ESR spectroscopy. Cyclic voltammetry shows that chloranil is complexated with the formed polymer. Radical formation increases with increasing degree of conversion. The soluble fraction of the conjugated PVT sections formed is capable of reacting with each other as evidenced by GPC data. Structure of PVT/silica and resulting hybrid materials have been investigated by solid state 13C {1H} CP MAS NMR-spectroscopy showing a reaction of methine and methylene hydrogen atoms after treatment with DDQ or chloranil as hydride acceptors. For all poly-(2-vinylthiophene)/hydride acceptor systems studied, chloranil has been found to be the best reagent for the transformation of PVT towards conjugated polymers. Transformation of PVT in poly(2-ethinylthiophene) (PET) and PVT-PET copolymers. [source] Structural determination of diterpenes from Daphne genkwa by NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2006Kalsoom Akhtar Abstract Five daphnane type diterpenes have been isolated from the chloroform soluble fraction of Daphne genkwa. The structure of the new compound (1) was assigned as 5,-hydroxyresiniferonol-6,,7,-epoxy-12,-acetoxy-9,13,14- ortho -2E -decenoate by extensive NMR studies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Leaf respiratory CO2 is 13C-enriched relative to leaf organic components in five species of C3 plantsNEW PHYTOLOGIST, Issue 3 2004Cheng-yuan Xu Summary ,,Here, we compared the carbon isotope ratios of leaf respiratory CO2 (,13CR) and leaf organic components (soluble sugar, water soluble fraction, starch, protein and bulk organic matter) in five C3 plants grown in a glasshouse and inside Biosphere 2. One species, Populus deltoides, was grown under three different CO2 concentrations. ,,The Keeling plot approach was applied to the leaf scale to measure leaf ,13CR and these results were compared with the ,13C of leaf organic components. ,,In all cases, leaf respiratory CO2 was more 13C-enriched than leaf organic components. The amount of 13C enrichment displayed a significant species-specific pattern, but the effect of CO2 treatment was not significant on P. deltoides. ,,In C3 plant leaves, 13C-enriched respiratory CO2 appears widespread. Among currently hypothesized mechanisms contributing to this phenomenon, non-statistical carbon isotope distribution within the sugar substrates seems most likely. However, caution should be taken when attempting to predict the ,13C of leaf respiratory CO2 at the ecosystem scale by upscaling the relationship between leaf ,13CR and ,13C of leaf organic components. [source] Role of Xanthurenic Acid 8- O -,- d -Glucoside, a Novel Fluorophore that Accumulates in the Brunescent Human Eye Lens,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2002Geetha Thiagarajan ABSTRACT We have been able to identify a blue fluorophore from the low-molecular weight soluble fraction of human adult nondiabetic brunescent cataract lenses as xanthurenic acid 8- O -,- d -glucoside (XA8OG) (excitation = 338 nm and emission = 440 nm). To determine the role of this fluorophore in the lens, we have examined its photophysical and photodynamic properties. We found XA8OG to have a fluorescence quantum yield (,) of 0.22 and a major emission lifetime of 12 ns. We found it to be a UVA-region sensitizer, capable of efficiently generating singlet oxygen species but little of superoxide. We also demonstrated that XA8OG oxidizes proteins when irradiated with UVA light, causing photodynamic covalent chemical damage to proteins. Its accumulation in the aging human lens (and the attendant decrease of its precursor O -,- d -glucoside of 3-hydroxykynurenine) can, thus, add to the oxidative burden on the system. XA8OG, thus, appears to be an endogenous chromophore in the lens, which can act as a cataractogenic agent. [source] Fatty acid synthase inhibitory activity of dibenzocyclooctadiene lignans isolated from Schisandra chinensisPHYTOTHERAPY RESEARCH, Issue S2 2010MinKyun Na Abstract Inhibition of fatty acid synthase (FAS) has been proposed to be a new therapeutic target for the treatment of cancer and obesity. In our preliminary screening study on the FAS inhibitory activity, a n -hexane soluble fraction prepared from the fruit of Schisandra chinensis (Schisandraceae) was found to inhibit FAS activity at 100,,g/mL. Nine dibenzocyclooctadiene lignans were isolated from the active fraction and were evaluated for their inhibitory effect on FAS for the first time. The compounds possessing a benzoyl or tigloyl group in the dibenzocyclooctadiene skeleton entirely inhibited the FAS activity in a dose dependent manner. The findings may be partially related to the anticancer effect of the medicinal plant, suggesting a further study on the anticancer potential of dibenzocyclooctadiene derivatives. Copyright © 2010 John Wiley & Sons, Ltd. [source] Isolation of coumarins and ferulate from the roots of Angelica purpuraefolia and the antitumor activity of khellactonePHYTOTHERAPY RESEARCH, Issue 5 2007Hyeong-Kyu Lee Abstract A new coumarin, hydroxylomatin (1), was isolated from the CHCl3 -soluble fraction of the roots of Angelica purpuraefolia, along with one ferulate (2) and three other known coumarins (3,5) including khellactone (3). The structure of hydroxylomatin (1) was determined to be 3,,,5,-dihydroxy-3,,4,-dihydroseselin (1) by spectroscopic means including 2D-NMR. The modified Mosher's method was used to determine the chiral center at C-1 of compound 2. Khellactone (3) is a major compound of the roots of A. purpuraefolia. This study also examined the antitumor activity of khellactone (3) using a LLC mouse lung carcinoma in the BDF-1 mice and a NCI-H460 human lung carcinoma in a human tumor xenograft model in nude mice. This compound (3) inhibited LLC tumor growth with a T/C (mean value of treated group/mean value of control group) value of 12.9% at a dose of 5 mg/kg and 33.2% at a dose of 10 mg/kg, respectively, in a dose-dependent manner. In addition, it suppressed the growth of NCI-H460 tumor cells, accounting for 81.4% at a dose of 10 mg/kg in nude mice. Copyright © 2007 John Wiley & Sons, Ltd. [source] Island clustering analysis for the comparison of the membrane and the soluble protein fractions of human brain proteomePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2008Kyung-Hoon Kwon Abstract A protein identified in multiple separate bands of a 1-D gel reflects variation in the molecular weight caused by alternative splicing, endoproteolytic cleavage, or PTMs, such as glycosylation or ubiquitination. To characterize such a protein distribution over the bands, we defined an entity called an ,island' as the band region including the bands of the same protein identified sequentially. We quantified the island distribution using a new variable called an Iscore. Previously, as described in Park et al.. (Proteomics 2006, 6, 4978,4986.), we analyzed human brain tissue using a multidimensional MS/MS separation method. Here, the new method of island analysis was applied to the previous proteome data. The soluble and membrane protein fractions of human brain tissue were reanalyzed using the island distribution. The proteome of the soluble fraction exhibited more variation in island positions than that of the membrane fraction. Through the island analysis, we identified protein modifications and protein complexes over the 1-D gel bands. [source] Physicochemical properties of the thermal gel of water-washed meat in the presence of the more soluble fraction of porcine sarcoplasmic proteinANIMAL SCIENCE JOURNAL, Issue 1 2007Yuji MIYAGUCHI ABSTRACT We investigated the physicochemical properties of the thermal gel of water-washed pork meat (WWM) in the presence of the soluble fraction of porcine sarcoplasmic protein (SP) obtained with ammonium sulfate at 75 percent saturation. Two precipitated fractions of SP were obtained at 0,50 percent and 50,75 percent saturation, named SP-f1 and SP-f2, respectively, and the soluble fraction obtained at 75 percent saturation, SP-f3, was used. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that SP-f3 contained mainly glyceraldehyde-3-phosphate dehydrogenase (GAPDH), while SP-f1 and SP-f2 had other SPs such as phosphorylase b, enolase, actin and phosphoglycerate mutase. The gel strength of WWM was greater when SP-f3 rather than one of various animal proteins such as bovine plasma (BP), egg white, or whey protein isolates (WPI), was added and SP-f3 had a gel-enhancing effect as good as that of polyphosphate (PP). The gel strength of WWM with added SP-f3 increased significantly with NaCl at 0.15 mol/L or more, but not in the absence of NaCl (0 mol/L). The effect of SP-f3 was evident at neutral pH and maximum gel strength was obtained at a pH above 6.0. Differential scanning calorimetric (DSC) analysis showed that an endothermic peak corresponding to myosin heads in WWM shifted to a lower temperature with the addition of SP-f3, as in the case of PP, though there was no such shift in the presence of other animal proteins (BP, egg white and WPI), suggesting that SP-f3 increases the gel strength of WWM through the dissociation of actomyosin similar to PP. Scanning electron microscopy (SEM) revealed wall-like structures among the protein strands in the WWM gel matrix in the presence of SP-f3. The results of DSC and SEM indicated that the formation of a gel network in meat products is reinforced with GAPDH in SP after the interaction between GAPDH and myofibrillar protein. [source] Purification, crystallization and preliminary X-ray analysis of Caenorhabditis elegans ubiquitin-conjugation enzyme M7.1ACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2003José A. Gavira M7.1 is a class IV ubiquitin-conjugation enzyme (UBC) that belongs to the ubiquitination cascade in Caenorhabditis elegans. The clone for this UBC has been overexpressed in Escherichia coli and the 16.7,kDa protein was purified from the soluble fraction. M7.1 was crystallized by sitting-drop vapor diffusion in 10% ethanol, 1.5,M NaCl at 277.5,K. Crystals diffracted to 1.75,Å and belong to the orthorhombic space group P212121, with unit-cell parameters a = 44.3, b = 54.3, c = 60.2,Å. The asymmetric unit contains a single monomer. A molecular-replacement model has been determined and refinement is in progress. [source] Plasmodium falciparum Rab6 GTPase: expression, purification, crystallization and preliminary crystallographic studiesACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2000Debasish Chattopadhyay The Plasmodium falciparumrab6 gene encodes a 208 amino-acid polypeptide. Two recombinant versions of P. falciparum Rab6 protein were expressed in Escherichia coli: the full-length protein and a truncated form containing residues 1,175. Both forms were purified from the soluble fraction of bacterial extract and were purified by ion-exchange chromatography and size-exclusion chromatography. Purified proteins were crystallized at pH 6.5 using the hanging-drop vapor-diffusion technique at room temperature. The full-length protein diffracted to 2.4,Å and belongs to the tetragonal space group P43212 or P41212, with unit-cell parameters a = b = 80.6, c = 90.4,Å. The crystals of the truncated protein were isomorphous with those of the full-length construct and diffracted X-rays to 2.2,Å resolution. [source] Purification of a crystallin domain of Yersinia crystallin from inclusion bodies and its comparison to native protein from the soluble fractionBIOMEDICAL CHROMATOGRAPHY, Issue 9 2006M. K. Jobby Abstract It has been established that many heterologously produced proteins in E. coli accumulate as insoluble inclusion bodies. Methods for protein recovery from inclusion bodies involve solubilization using chemical denaturants such as urea and guanidine hydrochloride, followed by removal of denaturant from the solution to allow the protein to refold. In this work, we applied on-column refolding and purification to the second crystallin domain D2 of Yersinia crystallin isolated from inclusion bodies. We also purified the protein from the soluble fraction (without using any denaturant) to compare the biophysical properties and conformation, although the yield was poor. On-column refolding method allows rapid removal of denaturant and refolding at high protein concentration, which is a limitation in traditionally used methods of dialysis or dilution. We were also able to develop methods to remove the co-eluting nucleic acids during chromatography from the protein preparation. Using this protocol, we were able to rapidly refold and purify the crystallin domain using a two-step process with high yield. We used biophysical techniques to compare the conformation and calcium-binding properties of the protein isolated from the soluble fraction and inclusion bodies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Long-term effects of crop rotation and fertilization on soil organic matter compositionEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2007M. Kaiser Summary Long-term effects of crop rotation and fertilization are mostly observed with respect to the amount of soil organic matter (SOM) and measured in terms of soil organic carbon (SOC). In this paper, we analyze the SOM composition of samples from long-term agricultural field experiments at sandy and clayey sites that include complex crop rotations and farm-yard manure applications. The organic matter (OM) composition of the soil samples, OM(Soil), and that of sequentially extracted water, OM(W), and sodium pyrophosphate, OM(PY), soluble fractions was analyzed using Fourier Transform Infrared Spectroscopy (FTIR). The fraction OM(PY) represented between 13 and 34% of SOC, about 10 times that of OM(W). Site specific differences in OM(Soil) composition were larger than those between crop rotations and fertilizer applications. The smaller C=O group content in FTIR spectra of OM(W) compared with OM(PY) suggests that analysis of the more stable OM(PY) fraction is preferable over OM(W) or OM(Soil) for identifying long-term effects, the OM(Soil) and OM(W) fractions and the content of CH groups being less indicative. Farm-yard manure application leads to a more similar content of C=O groups in OM(PY) between crop rotations and fertilizer plots at both sites. Short-term effects from soil tillage or potato harvesting on composition of OM require further studies. [source] The effect of additives in silages of pure timothy and timothy mixed with red clover on chemical composition and in vitro rumen fermentation characteristicsGRASS & FORAGE SCIENCE, Issue 3 2003M. Hetta Abstract The aim was to compare the effects of additives on direct cut silages of pure timothy and timothy mixed with tetraploid red clover. First and second growth cuts were ensiled during three consecutive years, 1994, 1995 and 1996, either without any additive or with the addition of formic acid, or lactic acid bacteria in combination with molasses. Effects of the additives on the degradation characteristics of the herbage and the silages were analysed using an automatic in vitro gas production (GP) technique. At the end of the in vitro procedures, organic matter and neutral-detergent fibre (NDF) degradabilities were determined. The tetraploid red clover persisted in the leys during the 3 years and was the dominant species at the second growth in the mixed leys. The herbage from the mixed crops had lower dry-matter contents, higher crude protein concentrations and higher buffering capacity compared with the pure timothy at both cuts. In general, the additives reduced pH, and the concentrations of ammonium-N and acetic acid in the silages. The treated silages had a more rapid faster GP in both crops. The silages from the mixed crop benefited more from the additives compared with the grass silages. The additives affected the soluble fractions as well as the NDF degradability of the silages of the mixed crop more than those fractions of the grass silages. The addition of molasses in combination with a commercial inocula resulted in increased production of lactic acid and ethanol in silages from both crops. The silages without additives could not meet the requirements for good silages according to the standards of the Swedish dairy industry. [source] | ||||||||||||||||||||||||||||||||||