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1.
The extract of Gynostemma pentaphyllum was tested to control the melanogenesis in B16 melanoma. Cytotoxic effect by the extract was observed when the dose concentration was higher than 2 mg/L. Most of the inhibitory effect was obtained by the reduced accumulation of extra-cellular melanin. When the extract was dosed as 2 mg/L, the extra-cellular melanin produced was only 24% of the control. Proteome analysis with 2-D PAGE showed that various proteins involved in melanogenesis were down-regulated by Gynostemma pentaphyllum. In addition to other proteins related to the intra-cellular melanogenesis, Rab-27b and Rab-38 could explain the remarkable decrease in extra-cellular melanin accumulation by reduced melanin transfer to keratinocyte.  相似文献   

2.
Bifunctional catalysts containing (0.1–0.5 wt%) Nickel and 0.1 wt% of Pd supported on H-β zeolite were synthesized by incipient wetness impregnation method and characterized by XRD, TEM, XPS, TPD and TPR techniques. The catalytic activity of Ni containing and Ni free Pd/H-β Catalysts was studied, and it was found that Ni up to a threshold value (0.3 wt% on β) produced increased the n-decane conversion and isomerization selectivity. When Ni content exceeds the threshold value, the conversion increases but isomerized products decrease. Moreover, Ni containing Pd/H-β showed increased sustainability and favored the protonated cyclopropane (PCP) intermediate mechanism in n-decane isomerization. The catalyst containing 0.3 wt% Ni 0.1 wt% Pd is adjudged as one performing better than other catalysts studied because of the isomerized mixture from it shows better octane number.  相似文献   

3.
Western flower thrips (Frankliniella occidentalis) has become a key insect pest of agricultural and horticultural crops worldwide. Little is known about host plant resistance to thrips. In this study, we investigated thrips resistance in F 2 hybrids of Senecio jacobaea and Senecio aquaticus. We identified thrips-resistant hybrids applying three different bioassays. Subsequently, we compared the metabolomic profiles of these hybrids applying nuclear magnetic resonance spectroscopy (NMR). The new developments of NMR facilitate a wide range coverage of the metabolome. This makes NMR especially suitable if there is no a priori knowledge of the compounds related to herbivore resistance and allows a holistic approach analyzing different chemical compounds simultaneously. We show that the metabolomes of thrips-resistant and -susceptible hybrids differed considerably. Thrips-resistant hybrids contained higher amounts of the pyrrolizidine alkaloids (PA), jacobine, and jaconine, especially in younger leaves. Also, a flavanoid, kaempferol glucoside, accumulated in the resistant plants. Both PAs and kaempferol are known for their inhibitory effect on herbivores. In resistant and susceptible F 2 hybrids, young leaves showed less thrips damage than old leaves. Consistent with the optimal plant defense theory, young leaves contained increased levels of primary metabolites such as sucrose, raffinose, and stachyose, but also accumulated jacaranone as a secondary plant defense compound. Our results prove NMR as a promising tool to identify different metabolites involved in herbivore resistance. It constitutes a significant advance in the study of plant–insect relationships, providing key information on the implementation of herbivore resistance breeding strategies in plants. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

4.
α-amylase from Bacillus licheniformis was successfully immobilized on developed support, which was prepared by coating a chitosan-casein film on silica, at 20 °C, pH 6.0 for 5 hr with microbial transglutaminase (MTG) as the cross-linking factor. The optimal support was obtained when 1% chitosan and 1% casein were used in the coating mixture. The optimal condition for immobilization catalyzed by MTG was confined to be at MTG concentration of 15 U/mL, pH 6.0, reacting for 6 hr at 20 °C. The highest specific activity of immobilized α-amylase was achieved as 236 U/g. After immobilization, the obtained enzyme showed broader pH profile and maintained more than 70% of the original activity after 20 reuses.  相似文献   

5.
TPD studies of n-hexane and n-heptane from NaX, Y and ZSM-5 (Na+ or H+ exchanged) in the experimental system with a TCD detector were performed, using pure He or He/n-alkane mixture as a carrier gas. The TPD profiles with one desorption peak for Y and two peaks for ZSM-5, measured using He/hydrocarbon mixture, were similar to the previously reported equilibrated thermodesorption results. TPD profiles were accurately fitted with a model based on the equilibrium control of the desorption and the adsorption functions derived from the Langmuir or dual site Langmuir isotherms.  相似文献   

6.
The effects of key parameters on the preparation and regeneration of protoplast from the β-carotene-producing fungus Blakeslea trispora were discussed in this paper, including the combination of various enzymes, mycelial age, digesting time and temperature, pH value, osmotic stabilizers, pretreatment, culture medium and culture method. Under the condition of mixed enzymes in osmotic stabilizer (0.6 M NaCl) combined with 2% lysozyme, 3% cellulase and 3% snailase, the highest protoplast yield, as high as 7.48×106 protoplasts/mL, was obtained when mycelial age was 60 h at pH 5.0–6.0 with digesting for 14–16 h at 28 °C. After purification of the obtained protoplasts, they were regenerated in PDA regenerative medium using bilayer plate culture method. To validate the usability of the protoplasts, a novel plasmid with green fluorescent protein (GFP) was used in transformation for easy visual observation. The results showed that the protoplasts prepared by the optimized method were active and applicable in further gene manipulation experiments. This work was presented at 13 th YABEC symposium held at Seoul, Korea, October 20–22, 2007.  相似文献   

7.
Dietary trans fatty acids (TFA) are of major concern because of their adverse effects on blood lipid levels and coronary heart disease. In Canada, margarines were significant sources of TFA during the 1980s and 1990s. However, this is expected to change with increased public awareness over their adverse health effects and the introduction of new legislature to include TFA content on the Nutritional Facts table of food labels. In this study, the TFA content of the top-selling 29 Canadian margarines, which represented 96.3% of the market share, was determined by capillary gas-liquid chromatography in order to assess the influence of regulatory development during the 3-year transition period between the announcement of new food labelling regulations in Canada that require mandatory declaration of the trans fat content in most pre-packaged foods in January 2003 and its enforcement on 12 December 2005. The 29 margarines included 15 tub margarines made from non-hydrogenated vegetable oils (NHVO-tub margarines), 11 tub margarines made from partially hydrogenated vegetable oils (PHVO-tub margarines) and three print margarines, which were also made from partially hydrogenated vegetable oils (PHVO-print margarines). The 15 NHVO tub-margarines accounted for 71% of the total margarine market share and generally contained less than 2% TFA (mean value 0.9 ± 0.3% of total fatty acids). The mean total TFA contents of PHVO-tub margarines and PHVO-print margarines, were 20.0 ± 4.5% and 39.6 ± 3.5%, and their market shares were 19.3 and 6.0%, respectively. Although during the last 10 years, increasing number of soft tub margarines that contained very little trans fats have been made available in Canada, the PHVO-tub- and -print margarines still contain high levels of trans fats similar to those margarines that were sold in the 1990s. The market share data suggest that the margarines prepared using NHVO and containing almost no TFA were preferred by Canadians over those margarines prepared using PHVO, even before the mandatory declaration of TFA content came into effect on 12 December 2005.  相似文献   

8.
The oil and meal from Monechma ciliatum (black mahlab) and Prunus mahaleb (white mahlab) seeds were characterized for their physicochemical properties. The oil content was found to be 30.95 and 13.15% in white and black mahlab seeds, respectively. The refractive indices of white mahlab oil (WMO) and black mahlab oil (BMO) were 1.475 and 1.470, and specific gravities were 0.8511 and 0.8167 g/cm3, respectively. Saponification values were 184.23 and 180.3 mg KOH/g, peroxide values were 2.54 and 4.43 meq/kg, and unsaponifiable matter was 0.92 and 0.66%, respectively. The major fatty acids were palmitic 4.5%, stearic 16.0%, oleic 47.3%, and linoleic 31.4% in BMO, while in WMO they were palmitic 5.7%, oleic 45.0%, and linoleic acid 47.0%. A moderate amount of tocopherols were found at 45.2 and 28.5 mg/100 g in BMO and WMO, respectively. Protein content was found to be 21% in black and 28% in white mahlab seeds. The total amount of amino acids in black and white mahlab seeds was found to be 783.3 and 1,223.2 mg/g N, respectively. The concentration (on ppm dry-weight basis) of major elements (Ca, K, and Mg) and of minor elements (Al, Pb Ni, Mn, Cu, Cr, Co, and Fe) was also determined in the meals.  相似文献   

9.
Reaction selectivities were determined in multicompetitive reactions mediated by Rhizomucor miehei (RM) lipase at water activity of 0.19 in hexane. Saturated FA (C4–C18 even chain) and oleic acid (C18∶1) were reacted with a single alcohol, glycerol, or α-or β-MAG containing C4, C10, C16, or C18∶1 individually as alcohol cosubstrate. Similar patterns of broad FA selectivity toward C8–C18 FA were generally observed for esterification into specific acylglycerol (AG) pools with the different α/β-CX-MAG cosubstrates. Exceptions were enrichment of C18 in the MAG pool with α-C16-MAG substrate, and a general suppression of C4/C6 FA reactivity and a specific discrimination toward >C8 FA incorporation into the TAG pool, both for reactions with α-C10- and α-C16-MAG. RM lipase selectivity toward MAG was in descending order: β-C18∶1-MAG>α/β-C4-MAG∼β-C10-MAG∼β-C16-MAG>α-C18∶1-MAG >α-C10-MAG∼α-C16-MAG. Selectivity in channeling CX of the original CX-MAG substrates into higher AG species was in descending order: α-C10-MAG∼α-C16-MAG>β-C10-MAGβ-C16-MAG>α-C18∶1-MAG>β-C18∶1-MAG∼ α/β-C4-MAG. Aside from their characteristic FA selectivity, Burkholderia cepacia (PS-30) and RM lipases behaved similarly in terms of MAG selectivity as well as a general conservation of FA selectivity throughout the sequential steps of TAG assembly from FA and glycerol for processes designed to yield specifically structured TAG.  相似文献   

10.
Age-related changes of antennal-active components of male labial gland extracts were studied in two closely related bumblebee species, Bombus terrestris and B. lucorum. In B. terrestris, compounds eliciting electroantennogram (EAG) responses of virgin queens were ethyl dodecanoate, 2,3-dihydrofarnesal, 2,3-dihydrofarnesol, hexadecan-1-ol, octadeca-9,12,15-trien-1-ol, and geranylcitronellol. Compounds that elicited EAG responses from queens of B. lucorum were ethyl dodecanoate, ethyl tetradec-7-enoate, ethyl tetradec-9-enoate, ethyl hexadec-9-enoate, hexadecan-1-ol, hexadec-7-enal, octadeca-9,12-dien-1-ol, octadeca-9,12,15-trien-1-ol, and octadecan-1-ol. Quantities of these compounds in the labial glands changed significantly over the lifetime of the respective males of the two species. In both species, concentrations of the respective compounds reached their maximum within seven days after eclosion. Subsequently, a rapid decrease in the amount of EAG-active compounds occurred in B. terrestris, whereas in B. lucorum the amount of active compounds stayed approximately constant or decreased at a slow rate. Microscopy showed that in B. terrestris secretory cells of the labial glands undergo apoptosis from the fifth to the tenth day of life, whilst in B. lucorum labial gland cells remain unchanged throughout the life of the males.  相似文献   

11.
Acacia nilotica var. tomentosa trees from the Diarra protected forest located in the Senegal River valley were identified for the assessment of both biological nitrogen fixation, using the natural abundance method, and soil bio-functioning parameters (nodulation, root biomass, total microbial biomass, and potential N mineralization). The presence and the genetic diversity of indigenous rhizobia nodulating A. nilotica var. tomentosa was also investigated, taking into account distance from the trunk (0, 1, 2, and 3 m) and depth (0–25, 25–50, and 50–75 cm). Surprisingly, no nodules on the trees root systems were found, whereas under laboratory conditions the presence of indigenous rhizobia nodulating A. nilotica var. tomentosa was demonstrated in the analyzed soils (90% of the nodules harvested on the trapped plants were occupied by the same Inter-Genic Spacer (IGS) group, IGS1). There was no significant influence of trees and/or depth on total microbial biomass and potentials of nitrogen mineralization. Some assumptions were formulated on the possible combined effect of flooding, which usually occurs annually during 4–7 months, and the clayey soils in the Diara forests. Although a deeply natural nodulation of A. nilotica var. tomentosa trees by indigenous rhizobia is not excluded, but it still remains to be demonstrated.  相似文献   

12.
Most epidemiological surveys have confirmed the association of low HDL-cholesterol and high triglyceride levels with cholesterol gallstones. Our objective was to analyze the relationship between plasma lipid levels and common polymorphisms of ABCB11 (encoding the bile salt export pump, BSEP) and ABCB4 (encoding the phospholipid transporter into bile, MDR3) genes. Plasma lipids were measured in 108 index patients of sib pairs with gallstones and in 260 controls. Using PCR-based assays with 5′-nuclease and fluorescence detection (TaqMan), the ABCB11 coding SNP p.A444V and four haplotype-tagging SNPs covering the ABCB4 gene (c.504C > T, c.711T > A, p.R652G, rs31653 in intron 26) were genotyped. Plasma lipids were compared in carriers of the common versus rare allele of these polymorphisms using Student’s t test and Pearson’s correlation. BMI and triglyceride levels were higher and HDL-cholesterol levels were lower in affected siblings than in controls. Among cases, triglyceride and cholesterol levels were higher in carriers of the common versus rare (hetero/homozygous carriers) allele of the SNPs p.A444V of ABCB11 and C.504C > T of ABCB4. HDL-cholesterol was lower in carriers of the common allele of rs31653. In controls, significant differences of cholesterol and HDL-cholesterol levels were found in carriers of ABCB4 polymorphisms. Our results do not support the hypothesis of a link between ABCB4 and ABCB11 polymorphisms, lithogenic dyslipidemia, and gallstone risk.  相似文献   

13.
The present work reports the characterization and comparison of Moringa concanensis seed oil from Tharparkar (a drought hit area), Pakistan. The hexane-extracted oil content of M. concanensis seeds ranged from 37.56 to 40.06% (average 38.82%). Protein, fiber, moisture and ash contents were found to be 30.07, 6.00, 5.88 and 9.00%, respectively. The extracted oil exhibited an iodine value of 67.00; a refractive index (40 °C) of 1.4648; its density (24 °C) was 0.8660 mg mL−1; the saponification value (mg of KOH g−1 of oil) was 179.00; unsaponifiable matter 0.78%; color (1 in. cell) 1.90R + 19.00Y; and acidity (% as oleic acid) 0.34%. Tocopherols (α, γ, and δ) in the oil accounted for 72.11, 9.26 and 33.87 mg kg−1, respectively. Specific extinctions at 232 and 270 nm were 3.17 and 0.65, respectively. The peroxide and p-anisidine values of the oil were found to be 1.75 and 1.84 meq kg−1, respectively. The induction periods (Rancimat, 20 L h−1, 120 °C) of the crude oil was 10.81 h and reduced to 8.90 h after degumming. The M. concanensis oil was found to contain high levels of oleic acid (up to 68.00%) followed by palmitic, stearic, behenic, and arachidic acids up to levels of 11.04, 3.58, 3.44 and 7.09%, respectively. The results of the present analytical study, compared with those for other Moringa species and different vegetable oils, showed M. concanensis to be a potentially valuable non-conventional seed crop for high quality oil.  相似文献   

14.
The electrochemical behavior of a new G-2-s-triazine-based dendrimer, 2,4,6-tris-{4-{4,6-bis-{4-{4,6-bis-[(1S,2S)-1,3-dihydroxy-1-(4-nitrophenyl)-prop-2-ylamino]-s-triazin-2-yl}-piperazin-1-yl}-s-triazin-2-yl}-piperazin-1-yl}-s-triazine, (I), was studied in dimethylsulfoxide solution by cyclic voltammetry, on platinum and graphite electrodes. The electrochemical properties of I were compared with that of one of its precursor, N-{4,6-bis{4-{4,6-bis[(1S,2S)-1,3-dihydroxy-1-(4-nitrophenyl)-prop-2-ylamino]-s-triazin-2-yl}-piperazin-1-yl}-triazin-2-yl}-piperazine), (II), together with that of the starting material, (1S,2S)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol (“p-nitrophenylserinol”), (III).  相似文献   

15.
In the present study, a series of ionic poly(N-t-butylacrylamide-co-acrylamide) [P(NTBA-co-AAm)] hydrogels were synthesized by free-radical crosslinking copolymerization of N-t-butylacrylamide (NTBA) and acrylamide (AAm) monomers in fixed amount, but changing amount of maleic acid (MA) comonomer in methanol using N,N-methylene-bis-acrylamide (BAAm) as the crosslinker, ammonium persulfate (APS) as the initiator, and N,N,N′,N′-tetramethylethylenediamine (TEMED) as the activator. The swelling behavior of these hydrogels was analyzed in buffer solutions at various pHs. The prepared hydrogels also were investigated swelling-deswelling transition in water depending on the temperature. For the bovine serum albumin (BSA) adsorption, the effect of pH, temperature, initial protein concentration and adsorption rate were investigated. Maximum BSA adsorption was observed at pH 5.0 which is close to the isoelectric pH of BSA (pH 4.8). The highest adsorption rate was achieved in about 12 h. and also, maximum BSA adsorption was found at +5°C.  相似文献   

16.
The electrochemical synthesis of poly(o -phenylenediamine) (PoPD) from an aqueous medium was suitably modified by controlling the switching potential to enhance the growth of the polymer. The charge–discharge data for the cell Zn/1 M ZnSO4 (pH 4)/PoPD are presented. The polymer was modified by incorporating Pt microparticles into its matrix during electropolymerization. The PoPD-Pt composite electrode was also characterized as a cathode active material in aqueous cells.  相似文献   

17.
To develop a novel skin depigmenting agent from natural sources, the inhibition of melanogenesis by the Chinese herb, Sterculia lynchnophera (SL), was evaluated. Treatment of B16F10 melanoma cells and melan-a cells with SL exhibited a 32.9% and 68.2% inhibition of melanin synthesis without cytotoxicity at a concentration of 200 μg/ml, respectively. This herb possessed a high free radical scavenging activity with IC50=11.02 μM. The methanol extract of SL slightly inhibited in vitro mushroom tyrosinase activity (23.4% at a concentration of 200 μg/ml) and had a significant inhibitory effect on cellular tyrosinase activivity (48.65% and 88.56% inhibition at the concentration 200 μg/ml in B16F10 cells and C57BL/6 melan-a cells, respectively). From the western blotting results, SL inhibited the expression of tyrosinase and tyrosinase related protein 1 (TRP-1). Taken together, we suggest that SL may be a safe and effective depigmentation agent.  相似文献   

18.
The objective of this study was to explore the extent of microbial conversion of lesquerolic acid (14-hydroxy-cis-11-eicosenoic acid; LQA) by whole cell catalysis and to identify the newly converted products. Among compost isolates including NRRL strains B-23212 (Sphingobacterium multivorum), B-23213 (Acinetobacter sp.), B-23257 (Enterobacter cloacae B), B-23259 (Escherichia sp.) and B-23260 (Pseudomonas aeruginosa) the S. multivorum strain was the only microorganism that converted LQA to produce a new product identified as 14-oxo-cis-11-eicosenoic acid by GC-MS and NMR analyses. The conversion yield was 47.4% in 48 h at 200 rpm and 28°C in small shake flask experiments. In comparison, both Acinetobacter and Pseudomonas strains failed to convert LQA to major new products but used LQA apparently as an energy source during fermentation. For structural analysis, 6.88 g of 14-oxo-cis-11-eicosenoic acid was produced from converting 11 g LQA (a 62% yield) in 72 h at 200 rpm and 28 °C in Fernbach flasks using 18-h-old NRRL B-23212 cultures and an improved medium that also contained EDTA and glycerol in lieu of glucose as carbon source. NRRL B-23212 was further identified by 16S rRNA gene sequence analysis as a unique strain of S. multivorum. Therefore, S. multivorum NRRL B-23212 possesses an enzymatic activity presumably a secondary alcohol dehydrogenase for converting LQA to produce 14-oxo-cis-11-eicosenoic acid, a first report that demonstrates the functional modification of LQA by whole cell catalysis.  相似文献   

19.
A series of comb like poly(p-n-alkylstyrene)s with linear alkyl groups, containing even numbers of carbon atoms from 12 up to 22 were synthesized by radical polymerization and characterized by FTIR, 1H NMR, TGA, TVA DSC, and WAXS. All polymers were obtained in good yields and were soluble in organic solvents as chloroform, dichloromethane or tetrahydrofuran and insoluble in methanol; they are stable up to temperatures near 300 °C. On the other hand, the alkylic side chains of all series are able to crystallize in a paraffinic phase in which the melting temperature and enthalpy increase with the methylene number of the n-alkyl chain.  相似文献   

20.
We tested differences in female pheromone production and male response in three species of the genus Adoxophyes in Korea. Females of all three species produced mixtures of (Z)-9-tetradecenyl acetate (Z9–14:OAc) and (Z)-11-tetradecenyl acetate (Z11–14:OAc) as major components but in quite different ratios. The ratio of Z9–14:OAc and Z11–14:OAc in pheromone gland extracts was estimated to be ca. 100:200 for Adoxophyes honmai, 100:25 for Adoxophyes orana, and 100:4,000 for Adoxophyes sp. Field tests showed that males of each species were preferentially attracted to the two-component blends of Z9–14:OAc and Z11–14:OAc mimicking the blends found in pheromone gland extracts of conspecific females. The effects of minor components identified in gland extracts on trap catches varied with species. Addition of 10-methyldodecyl acetate (10me-12:OAc) or (E)-11-tetradecenyl acetate (E11–14:OAc) to the binary blend of Z9–14:OAc and Z11–14:OAc significantly increased captures of A. honmai males, whereas E11–14:OAc exhibited a strongly antagonistic effect on catches of Adoxophyes sp. males. Moreover, (Z)-9-tetradecen-1-ol (Z9–14:OH) or (Z)-11-tetradecen-1-ol (Z11–14:OH) added to the binary blends increased attraction of male A. orana but not A. honmai and Adoxophyes sp. males, suggesting that these minor components, in addition to the relative ratios of the two major components, play an important role in reproductive isolation between Adoxophyes species in the southern and midwestern Korea where these species occur sympatrically.  相似文献   

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