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1.
To study the ability of long-chain trans fatty acids (FA) to be incorporated and metabolized into endothelial cells, bovine aortic endothelial cells were incubated with medium enriched eicosapentaenoic acid (EPA) bound to albumin (M2) or one of its geometrical isomers: 20∶5 5c,8c,11t,14c,17c(M3), 20∶5 5c,8c,11c,14c,17t(M4), or 20∶5 5c,8c,11t,14c,17t(M5). After 48 h of incubation, supernatant and cells were harvested and their lipids were analyzed, including prostacyclin synthesis. EPA and 22∶5n−3 of endothelial cells incubated with M2 were, respectively, three and two times higher than in control cells (incubated in M1, without any fatty acid added), whereas 22∶6n−3 increased only in the supernatant, suggesting its release after biosynthesis. However, 18∶2n−6 and 22∶4n−6 decreased (about 30%). Trans 20∶5 isomers represented 4.7, 3.9, and 5.2% of total phospholipid FA in endothelial cells incubated with M3, M4, and M5, respectively. They were elongated into trans 22∶5 and trans 24∶5, as revealed by gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared analysis. In cells incubated with M2, M3, M4, and M5, prostacyclin synthesis was inhibited by 49.0, 62.5, 60.5, and 72.0%, respectively. This effect may be due to less available arachidonic acid in the cells and to a competition between EPA isomers and AA at the level of cyclooxygenase pathway, as it was demonstrated that 20∶5 Δ17t was metabolized by this enzyme.  相似文献   

2.
Ascorbic acid is one of the important antioxidant nutrients that can aid in the prevention of oxidative cellular damage. Adequate dietary intake is essential as humans can not synthesize this vitamin. It has been reported that smokers require higher dietary intakes to maintain their serum levels. The objective of this study was to determine serum levels of ascorbic acid in young male smokers and non smokers in the city of Hermosillo, Sonora, Mexico. In addition, their dietary intake of ascorbic acid was determined by a 24 h dietary recall. The dietary intake of ascorbic acid in 12 smokers was 64 +/- 11 mg/d and in 13 non smokers it was 70 +/- 12 mg/d. The smokers in this study did not meet the dietary recommendation of 100 mg/d. Serum ascorbic acid values in smokers and non smokers were 24.2 +/- 6.9 mumol/L and 30.9 +/- 3.7 mumol/L respectively. No significant difference was found among the 2 groups. Although the average serum ascorbic acid values fell within the range considered normal, 50% of the smokers had individual values that were below 23 mumol/L, indicating that these subjects have hipovitaminosis. A positive correlation between intake and serum levels was obtained for smokers (r = 0.71; p = 0.03). The results of this study suggest smokers may be at increased risk for chronic diseases due to their low intake and low serum levels of ascorbic acid.  相似文献   

3.
Consumption of trans fatty acids (TFA) has been associated with a higher risk of coronary heart diseases. In our daily food pattern two different sources of TFA can be distinguished: ruminant TFA and industrial TFA. Controversy exists between the health effects of both sources. Now, new findings are available in which both TFA sources are investigated in intervention studies. Also, an epidemiological study is published in which a wide intake of ruminant TFA is investigated. These data suggest that there is no nutritional difference between the sources. However, total TFA intake in most European countries is nowadays already reduced to recommendation levels, so that the risk of coronary heart diseases is not increased anymore. Focus should be addressed to other issues like reduction of saturated fatty acids.  相似文献   

4.
Conjugated linoleic acid (CLA) mixtures were isomerized with p-toluenesulfinic acid or I2 catalyst. The resultant mixtures of the eight cis/trans geometric isomers of 8,10-, 9,11-, 10,12-, and 11,13-octadecadienoic (18∶2) acid methyl esters were separated by silver ion-high-performance liquid chromatography (Ag+-HPLC) and gas chromatography (GC). Ag+-HPLC allowed the separation of all positional CLA isomers and geometric cis/trans CLA isomers except 10,12–18∶2. However, one of the 8,10 isomers (8cis, 10trans-18∶2) coeluted with the 9trans,11cis18∶2 isomer. There were differences in the elution order of the pairs of geometric CLA isomers resolved by Ag+-HPLC. For the 8,10 and 9,11 CLA isomers, cis,trans eluted before trans,cis, whereas the opposite elution pattern was observed for the 11,13–18∶2 geometric isomers (trans,cis before cis,trans). All eight cis/trans CLA isomers were separated by GC on long polar capillary columns only when their relative concentrations were about equal. Large differences in the relative concentration of the CLA isomers found in natural products obscured the resolution and identification of a number of minor CLA isomers. In such cases, GC-mass spectrometry of the dimethyloxazoline derivatives was used to identify and confirm coeluting CLA isomers. For the same positional isomer, the cis,trans consistently eluted before the trans,cis CLA isomers by GC. High resolution mass spectrometry (MS) selected ion recording (SIR) of the molecular ions of the 18∶1 18∶2, and 18∶3 fatty acid methyl esters served as an independent and highly sensitive method to confirm CLA methyl ester peak assignments in GC chromatograms obtained from food samples by flame-ionization detection. The high-resolution MS data were used to correct for the nonselectivity of the flame-ionization detector.  相似文献   

5.
Sillimanite, kyanite and andalusite areadvantageous natural refractory raw materials foraluminosilicate refractories to attain improved keyproperties. This paper are divided into two parts tointroduce their resource and technical characteristicin the first part, and their applications in refracto-ries in the second part to be succeeded. In this part,based on authors' knowledge and sources, informa-tion on their reserve, distribution, composition and  相似文献   

6.
Sillimanite,kyanite and andalusite are advantageous natural refractory raw materials for aluminosilicate refactories to attain improved key properties.This paper are divided into parts to introduce their resource and technical characteristic in the first part,and their applications in refractories in the second aprt to be succeeded.In this part,based on authors‘ knowledge and sources,information on their reserve,distribution,composition and characteristic is provided,to bring it to light that China is rich in the reserve of them,in particular andalusite.The sillimanite group minerals are characterized by their phase transformation to form primary mullite and secondary mullite when added in high alumina system,accompanied by volume expansion,which can be taken use to improve creep resistances and thermal shock resistance of the related refractories.  相似文献   

7.
Near-infrared (NIR)-emitting fluorescent probes are widely used for molecular imaging at the whole-body level. However, NIR-emitting fluorescent probes emitting over λ=700 nm are not suitable for molecular imaging at the cellular level, because most of the conventional fluorescence microscopes have very low optical sensitivity in the NIR region. Thus, to achieve fluorescence imaging at the cellular and whole-body levels by using single probes, visible and NIR-emitting dual-color fluorescent probes are desirable. For dual-color fluorescence molecular imaging, we synthesized fluorescent, recombinant-protein-conjugated, NIR-emitting quantum dots (QDs), in which the recombinant protein consists of enhanced green fluorescent protein (EGFP) and the immunoglobulin binding domain (B1) of protein G. This dual-color fluorescent QD probe binds the Fc region of immunoglobulin G (IgG) through its B1 domain at the QD surface and acts as a molecular-imaging probe at both the cellular and whole-body levels. In this paper, we present the synthesis of fluorescent, recombinant protein (HisEGFP-GB1)-conjugated, NIR-emitting QDs and their application to the dual-color molecular imaging of breast cancer cells in vitro and in vivo.  相似文献   

8.
1 INTRODUCTION 2-Methyl-6-acetylnaphthalene (2,6-MAN) is a type of white or pale yellow, powdery crystal, with a melting point of 332.15K. It is an important interme- diate[1] used for producing 2,6-naphthalene dicarbox- ylic acid (2,6-NDA), which has very extensive appli- cations in not only the light, electronic, and defense industries, but in many other areas. In particular, 2,6-NDA is an important monomer of liquid crystal polyester material (LCP) and polyethylene naphtha- lene-2…  相似文献   

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It is known that fatty acids (FA) regulate lipid metabolism by modulating the expression of numerous genes. In order to gain a better understanding of the effect of individual FA on lipid metabolism related genes in rainbow trout (Oncorhynchus mykiss), an in vitro time‐course study was implemented where twelve individual FA (butyric 4:0; caprylic 8:0; palmitic (PAM) 16:0; stearic (STA) 18:0; palmitoleic16:1n‐7; oleic 18:1n‐9; 11‐cis‐eicosenoic 20:1n‐9; linoleic (LNA) 18:2n‐6; α‐linolenic (ALA) 18:3n‐3; eicosapentenoic (EPA) 20:5n‐3; docosahexaenoic (DHA) 22:6n‐3; arachidonic (ARA) 20:4n‐6) were incubated in rainbow trout liver slices. The effect of FA administration over time was evaluated on the expression of leptin, PPARα and CPT‐1 (lipid oxidative related genes). Leptin mRNA expression was down regulated by saturated fatty acids (SFA) and LNA, and was up regulated by monounsaturated fatty acids (MUFA) and long chain PUFA, whilst STA and ALA had no effect. PPARα and CPT‐1mRNA expression were up regulated by SFA, MUFA, ALA, ARA and DHA; and down regulated by LNA and EPA. These results suggest that there are individual and specific FA induced modifications of leptin, PPARα and CPT‐1 gene expression in rainbow trout, and it is envisaged that such results may provide highly valuable information for future practical applications in fish nutrition.  相似文献   

13.
本文研究了反式,反式-1,4-二苯基-1,3-丁二烯(DPB)在沸石NaZSM-5中的光敏氧化反应.在溶液中9,10-二氰基蒽(DCA)敏化光氧化反应有两种机制:单重态氧机制和电子转移产生超氧负离子机制.我们把DPB吸附在沸石ZSM-5孔道中,DCA溶解于沸石外部溶剂季戊四醇三甲醚中,溶剂和敏化剂都不能进入沸石孔道.光照反应后,在沸石孔道中只得到DPB的单重态氧的反应产物,没有电子转移的产物产生.反应产物产率为100%.大大提高了反应的选择性  相似文献   

14.
Quantitative procedures employing liquid-chromatography/particle beam mass spectrometry (LC/PB-MS) and gas chromatography-mass spectrometry (GC-MS) were applied to the determination of the endogenous and 13C-labeled β-carotene, lutein, and retinol in plasma of a subject who consumed kale (Brassica oleracea) that had been grown in a 13CO2-enriched atmosphere. All compounds were analyzed in the negative chemical ionization (NCI) mode using methane as the moderating reagent gas. β-Carotene and lutein were analyzed using LC/PB-MS applying reversed-phase high-performance liquid chromatography (HPLC) separation procedures to resolve the analytes. The concentrations of the β-carotene isotopomers in the plasma over a several-week period were determined using 2H8-β-carotene as an internal standard. The total plasma concentrations of all trans-lutein were quantified by HPLC analysis with a photodiode array detector using β-apo-8′-carotenal as an internal standard, and the ratio of the 13C∶12C isotopomers of lutein was determined by PB-MS. The retinol isotopomers were collected from individual HPLC fractions of the plasma extract and then analyzed as the trimethylsilyl ethers by GC-MS in the NCI mode. The 13C-and 12C-retinol isotopomers were quantified using 2H4-retinol as an internal standard. These methods demonstrate the application of highly sensitive procedures empolying NCI MS for the quantitative determination of carotenoids and vitamin A for the purpose of conducting metabolism studies of phytonutrients.  相似文献   

15.
Glioblastoma (GBM) is one of the most aggressive tumors of the central nervous system, characterized by a wide range of inter- and intratumor heterogeneity. Accumulation of fatty acids (FA) metabolites was associated with a low survival rate in high-grade glioma patients. The diversity of brain lipids, especially polyunsaturated fatty acids (PUFAs), is greater than in all other organs and several classes of proteins, such as FA transport proteins (FATPs), and FA translocases are considered principal candidates for PUFAs transport through BBB and delivery of PUFAs to brain cells. Among these, the CD36 FA translocase promotes long-chain FA uptake as well as oxidated lipoproteins. Moreover, CD36 binds and recognizes thrombospondin-1 (TSP-1), an extracellular matrix protein that was shown to play a multifaceted role in cancer as part of the tumor microenvironment. Effects on tumor cells are mediated by TSP-1 through the interaction with CD36 as well as CD47, a member of the immunoglobulin superfamily. TSP-1/CD47 interactions have an important role in the modulation of glioma cell invasion and angiogenesis in GBM. Separately, FA, the two membrane receptors CD36, CD47, and their joint ligand TSP-1 all play a part in GBM pathogenesis. The last research has put in light their interconnection/interrelationship in order to exert a cumulative effect in the modulation of the GBM molecular network.  相似文献   

16.
Astrans-2-nonenal (T2N) acts as an insect repellent, an insecticide, and a flavor compound, it would be desirable to manipulate its concentration in plants. Simple, rapid, and accurate trapping on cartridges of activated charcoal detected T2N in headspace over carrot roots and regenerants. Concentrations ranged from 0.07 to 0.43 ppm total volatiles over the homogenized roots of a range of European carrot cultivars with the following statistically significant differences: Long Chantenay > Sytan > Vertou > Touchon Prima. This suggests that the expression of T2N is determined genetically. Given the potential for genetic manipulation byin vitro techniques, the release of T2N and other terpenoids was monitored in carrot cell suspensions and in hairy root cultures of cv. Gelbe Rheinische. T2N concentrations were 6.23 ppm and 0.005 ppm, respectively, as compared with 0.15 ppm over the homogenized root of the same cultivar. Two terpenoids additional to T2N were detected from cell suspension cultures as compared with 14 from hairy root cultures. The ready detection in regenerants of this significant aldehyde indicates that its presence could be monitored in derivatives of otherin vitro manipulations.  相似文献   

17.
以三种脂肪醇正辛醇、月桂醇和肉豆蔻醇为原料,合成得到三种谷氨酸二烷基酯核糖醇(2C8GE、2C12GE和2C14GE),比较了不同谷氨酸二烷基酯核糖醇及其浓度和所用溶剂,以及缓冲液pH、包衣时间、温度和干燥方式对包衣Lactobacillus helveticus L7菌体酶活的影响。确定了制备包衣菌体的条件为:表面活性剂为谷氨酸二十二烷基酯核糖醇(2C12GE),配制成质量百分比1.0%(w/w)的丙酮溶液;菌体用pH5.8的磷酸盐缓冲液重悬;在4℃下处理4 h经冷冻干燥而成。在以亚油酸为底物时包衣菌体中亚油酸异构酶的Km为35.7 mM,Vmax为5.6 mM/h。经包衣处理后,菌体中亚油酸异构酶和底物的亲和力有所降低。  相似文献   

18.
The heating of cis-[ReO2I(PPh3)2] at reflux in benzene in air led to the isolation of the rhenium(VI) complex [ReO2I2(PPh3)2] (1). The compound is centrosymmetric around the octahedrally coordinated rhenium center, and the ReO bond length of 1.797(2) Å is longer than in typical trans-dioxorhenium(V) complexes. The asymmetric ReO stretching frequency occurs at 744 cm 1. Density functional theory has been used for the calculation of the vibrational spectrum density which confirms the experimental asymmetric ReO stretching frequency. DFT calculation within the polarizable continuum model shows that complex 1 is more stable in CH2Cl2 than in the gas phase. EPR spectroscopy confirms a single d electron in 1. The crystal structure was determined by X-ray single crystal diffraction. In addition, infra-red, redox and electronic properties are also reported.  相似文献   

19.
Ti x SiBEA zeolites (x = 1.5, 3.2 and 5.8 Ti wt%) are prepared by a two-step postsynthesis method involving (1) dealumination of TEABEA zeolite by nitric acid leading to nests of SiO–H groups in vacant T-atom sites and (2) incorporation of Ti into SiBEA zeolite by reacting TiCl4 vapor with those silanol groups. The incorporation of Ti into the SiBEA framework is evidenced by XRD, 29Si MAS NMR, 1H–29Si CP MAS NMR and 1H MAS NMR. DR UV–vis and XPS investigations show that, for low Ti content, mainly framework tetrahedral Ti(IV) ions are present in Ti x SiBEA zeolites. On the basis of XPS data, the quantification of framework tetrahedral Ti(IV) and framework and/or extra-framework octahedral Ti(IV) ions is followed as a function of Ti content.  相似文献   

20.
The viceroy-monarch and viceroy-queen butterfly associations are classic examples of mimicry. These relationships were originally classified as Batesian, or parasitic, but were later reclassified as Müllerian, or mutalistic, based on predator bioassays. The Müllerian reclassification implies that viceroy is unpalatable because it too is chemically defended like the queen and the monarch. However, unlike the queen and the monarch, the viceroy defensive chemistry has remained uncharacterized. We demonstrate that the viceroy butterfly (Limenitis archippus, Nymphalidae) not only sequesters nonvolatile defensive compounds from its larval host-plant, the Carolina willow (Salix caroliniana, Salicaceae), but also secretes volatile defensive compounds when disturbed. We developed liquid chromatography-mass spectrometry-mass spectrometry methods to identify a set of phenolic glycosides shared between the adult viceroy butterfly and the Carolina willow, and solid phase microextraction and gas chromatography-mass spectrometry methods to identify volatile phenolic compounds released from stressed viceroy butterflies. In both approaches, all structures were characterized based on their mass spectral fragmentation patterns and confirmed with authentic standards. The phenolics we found are known to deter predator attack in other prey systems, including other willow-feeding insect species. Because these compounds have a generalized defensive function at the concentrations we described, our results are consistent with the Müllerian reclassification put forth by other researchers based on bioassay results. It seems that the viceroy butterfly possesses chemical defenses different from its monarch and queen butterfly counterparts (phenolic glycosides vs. cardiac glycosides, respectively), an unusual phenomenon in mimicry warranting future study.  相似文献   

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