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1.
ABSTRACT

The coat colour in mammals is determined by the relative amounts of eumelanin (black/brown) and phaeomelanin (red/yellow), produced in melanocytes, which are controlled by melanocyte stimulating hormone receptor (MSH-R). Melanocyte stimulating hormone receptor is activated by α-melanocyte-stimulating hormone (α-MSH). Stimulated MSH-R activates adenylyl cyclase (AC), thereby increasing the amount of cyclic AMP in the cell, which activates the enzyme tyrosinase resulting in eumelanin synthesis. In this study the complete coding sequences of five alleles of the MSH-R gene found in Holstein, Red Holstein, Simmental, and Brown Swiss cattle were cloned into a mammalian expression vector and transfected into human embryonic kidney (HEK) 293 cells. The expressed receptors were analyzed for their ability to increase intracellular cAMP in response to stimulation by α-MSH. The recessive red allele (e) found in Red Holstein and Simmental and the dominant black allele (ED) found in Holstein were unresponsive to a wide range of α-MSH concentrations. Two alleles from Brown Swiss (Ed1, Ed2) and one allele found in the Simmental breed (ef) responded to stimulation by α-MSH in a dose-dependent manner. When compared to Ed1 and Ed2, the cells transfected with the ef MSH-R allele, however, reached the corresponding intracellular cAMP concentrations at a 10-fold higher concentration of α-MSH. In conjunction with the mode of inheritance of coat colour, the results indicate that the e MSH-R allele is a non-functional receptor, ED is constitutively activated receptor, and Ed1 and Ed2 are hormonally activated receptors. The delay in ef MSH-R response may explain the similarity between the e and ef phenotypes.  相似文献   

2.
Seven new triterpene glycosides, erylosides R1 (1), T1 (3), T2 (4), T3 (5), T4 (6), T5 (7), and T6 (8) along with the known formoside (2) were isolated from the sponge Erylus formosus collected along the Caribbean coast of Mexico. Glycoside 1 was determined as a trisaccharide, glycoside 2 as a tetrasaccharide while glycosides 38 were hexasaccharide. Their carbohydrate chains were unprecedented and have never been found in oligosaccharides from other biological sources, except Erylus spp. Three carbohydrate chains in the glycosides 3 and 6, 4 and 7, 5 and 8 correspondingly are new. The glycosides 15 have penasterol as aglycone while glycosides 68 proved to be glycoconjugates of 24-methylene-14-carboxy-lanost-8(9)-en-3β-ol.  相似文献   

3.
A useful route is described for obtaining Z and E unsaturated alkylating agents 3 and 4. Coupling 6-azauracils 5 and 6 with unsaturated alkylating agent followed by the deprotection with H+ resin gave acyclonucleosides 11–14 in good overall yields. Unsaturated acyclonucleosides phosphonates 19 and 20 were prepared using potassium carbonate as base and 4-bromobut-2-enyl diethyl phosphonate 16 as the alkylating agent. The introduction of a propargyl group at the N-3 position of acyclonucleosides 7, 8, 17, 18, 19, and 20 was achieved using potassium carbonate in DMF.  相似文献   

4.
Abstract

Various routes to the targets 1, 2, 3, 1-deoxy-psicofuranosyl nucleoside analogues related to anti-HIV agents, are reported. Two routes afforded their 6′-benzylated derivatives 9, 10 and 15. Only the epoxide 12 and deoxynucleosides 19 and 22 were able to be deprotected leading in the first case to 16 and its ring opening derivative 17 and in the second case to 20 and to the target 3.  相似文献   

5.

The Z- and E-thymine and cytosine pronucleotides 3d, 4d, 3e, and 4e of methylenecyclopropane nucleosides analogues were synthesized, evaluated for their antiviral activity against human cytomegalovirus (HCMV), herpes simplex virus 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human immunodeficiency virus type 1 (HSV-1), and hepatitis B virus (HBV) and their potency was compared with the parent compounds 1d, 2d, 1e, and 2e. Prodrugs 3d and 4d were obtained by phosphorylation of parent analogues 1d or 2d with reagent 8. A similar phosphorylation of N4-benzoylcytosine methylenecyclopropanes 9a and 9b gave intermediates 11a and 11b. Deprotection with hydrazine in pyridine–acetic acid gave pronucleotides 3e and 4e. The Z-cytosine analogue 3e was active against HCMV and EBV. The cytosine E-isomer 4e was moderately effective against EBV.  相似文献   

6.
Conferin (1), a new isoflavone, has been isolated from the ethyl acetate soluble fraction of Caragana conferta Benth. along with seven known compounds, namely biochanin A (2), p-hydroxybenzoic acid (3), 3,5- dimethoxybenzoic acid (4), ursolic acid (5), erythrodiol (6), pinoresinol (7), and syringresinol (8), reported for the first time from this species. The structure of the new isoflavone was deduced on the basis of spectroscopic studies. Compounds 1 and 2 were investigated for biological activities and showed significant anti-inflammatory activity in carrageenan induced paw edema of rats. Evaluation of antioxidant activity by the radical scavenging method indicated that compound 1 is a potent antioxidant while 2 is moderately active. It was also shown that the reducing capability of compound 2 was remarkably increased in a concentration dependent manner as compared to 1. Compound 1 showed moderate inhibitory activity against the enzyme lipoxygenase, while 2 showed weak activity.  相似文献   

7.
The generalised anomeric effect (GAE) and gauche effect (GE) associated with donor–acceptor delocalisations, dipole–dipole interactions and total steric exchange energies (TSEE) on the conformational properties of 2-methoxy- (1), 2-methylthio- (2), 2-methylseleno- (3), 2-fluoro- (4), 2-chloro- (5) and 2-bromocyclohexanone (6) have been studied by means of ab initio and hybrid density functional theory methods and natural bond orbital (NBO) analysis. All methods used showed that the axial conformation stability increased from 2-methoxy- (1) to 2-methylselenocyclohexanone (3) and also from 2-fluoro- (4) to 2-bromocyclohexanone (6), which is in agreement with reported NMR data. The results obtained by complete basis set 4 (CBS-4), B3LYP/6-311+G** and HF/6-311+G** levels for compounds 1, 5 and 6 are very similar, but the CBS-4 results for compound 4 are not in agreement with the reported experimental data (vapour phase). The NBO analysis showed that the GAE increases from compounds 1 to 3 and also from compounds 4 to 6. The low axial conformer populations of compounds 1 and 4 can be reasonably explained by their small GAE. GE does not have significant impact on the conformational behaviours of compounds 16 and GAE succeeds in accounting qualitatively for the increase in the axial preferences in both series of compounds. The results showed that the calculated Δ(TSEEeq–ax) values decrease from compounds 4 to 6 which contradicts the suggested arguments in the literature about these compounds. On the other hand, the calculated differences between the dipole moment values of the axial and equatorial conformations, Δ(μeq ? μax), increase from compounds 1 to 2, but decrease from compounds 2 to 3 and also decrease from compounds 4 to 6. The calculated GAE values are more significant for the explanation of the conformational preferences of compounds 16 than the dipole–dipole repulsion effects. The correlations between the GAE, GE, dipole–dipole interactions, Wiberg Bond Index, TSEE, donor and acceptor orbital energies and occupancies, structural parameters and conformational behaviour of compounds 16 have been investigated.  相似文献   

8.
A methanolic extract of dried leaves of Polygala japonica Houtt (Polygalaceae) significantly attenuated nitric oxide production in lipopolysaccharide-simulated BV2 microglia. Five anthraquinones chrysophanol (1), emodin (2), aloe-emodin (3), emodin 8-O-β-D-glucopyranoside (4) and trihydroxy anthraquinone (5), and four flavonoids kaempferol (6), chrysoeriol (7), kaempferol 3-gentiobioside (8) and isorhamnetin (9) were isolated from the methanolic extract using bioactivity-guided fractionation. Among them, compounds 14, 6 and 7 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia at the concentrations ranging from 1.0 to 100.0 μM.  相似文献   

9.
Regioselective alkylation of 5-(3-chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole (1) with hydroxy alkylating agents 2, 3, 13, and the 2,3-O-isopropylidene-1-O-(p-tolylsulfonyl)-glycerol (10) afforded the corresponding S-alkylated derivatives 6, 7, 11, and 14 under both conventional and microwave irradiation conditions; bentonite as a solid support gave better results, with no change in regioselectivity. A facile intramolecular dehydrative ring closure of 6, 7, 11, and 14 using K2CO3 in DMF afforded the corresponding fused triazolo-thiazines and thiazolo-triazole 17–19. The isopropylidenes and acetyl derivatives of the products were prepared.  相似文献   

10.
New acylated 5‐thio‐β‐d‐glucopyranosylimino‐disusbstituted 1,3,4‐thiadiazols 8, and 11 were prepared, via spontaneous rearrangements, by cycloaddition of the glycosyl isothiocyanate 2 with the reactive intermediates 1‐aza‐2‐azoniaallene hexachloroantimonates 4 and 6, respectively. Reaction of 2 with aminoacetone or chloroethylamine afforded the acylated 5‐thio‐β‐d‐glucopyranosyl‐4‐imidazoline‐2‐thione nucleoside 16 and glucopyranosylamino‐2‐thiazoline derivative 18, respectively. Deblocking of 8, 11, 17 and 19 furnished the free nucleoside analogues 9, 12, 18 and 20, respectively. Analogously, treatment of 2 with chloroethylamine in the 1:2 ratio afforded the thioureylendisaccharide 21. No in vitro antiviral activity against HIV‐1, HIV‐2, human cytomegallovirus (HMCV), has been found for the new synthesized compounds.  相似文献   

11.
New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.  相似文献   

12.
This study describes the changes undergone by cells of the salivary glands of unfed and feeding (at day two and four post-attachment) Rhipicephalus sanguineus males, as well as new cell types. In unfed males, types I and II acini are observed with cells “undifferentiated”, undefined 1 and 2 (the latter, with atypical granules), a, c1 and c3; type III is composed of cells d and e; and type IV present cells g. In males at day two post-attachment, type I acini exhibit the same morphology of unfed individuals. An increase in size is observed in types II, III, and IV, as cells are filled with secretion granules. Some granules are still undergoing maturation. In type II acinus, cells a, b and c1c8 are observed. Cells c7 and c8 are described for the first time. Cells c7 are termed as such due to the addition of polysaccharides in the composition of the secretion granules (in unfed individuals, they are termed undefined 1). Type III acini exhibit cells d and e completely filled with granules, and in type IV, cells g contain granules in several stages of maturation. In males at day four post-attachment, type I acini do not exhibit changes. Granular acini exhibit cells with fewer secretion granules, which are already mature. In type II acini, cells a, b, c1c5 are present, type III exhibit cells d and e, and type IV contain cells g with little or no secretion. This study shows that in the salivary glands of R. sanguineus males, cells a, c1, and c3 of type II acinus, and cells d and e of type III do not exhibit changes in granular content, remaining continuously active during the entire feeding period. This indicates that during the intervals among feeding stages, gland cells reacquire the same characteristics found in unfed individuals, suggesting that they undergo reprogramming to be active in the next cycle.  相似文献   

13.
Abstract

To develop naphthyridine derivatives as anticancer candidates, pharmacokinetic (PK) evaluations of 10 novel derivatives of 1,4-dihydro-4-oxo-1-proparagyl-1,8-naphthyridine-3-carboxamide, with potent anticancer activity were done using in vitro ADME (absorption, distribution, metabolism, excretion) and pharmacokinetic--pharmcodynamic (PK/PD) assays. Only derivatives 5, 6, 9 and 10 showed better metabolic stability, solubility, permeability, partition coefficient and cytochrome P450 (CYP) inhibition values. PK of derivatives 5, 6, 9 and 10 in rat showed comparable PK profile for derivative 5 (C0?=?6.98?µg/mL) and 6 (C0?=?6.61?µg/mL) with no detectable plasma levels for derivatives 9 and 10 at 5.0?mg/kg i.v. dose. PK/PD assay of derivatives 5 and 6 in tumor-bearing mice (TBM) showed comparable PK but tumor plasma index (TPI) of derivative 6 (4.02) was better than derivative 5 (2.50), suggesting better tumor uptake of derivative 6. Derivative 6, as lead compound, showed highest tumor growth inhibition (TGI) value of 33.6% in human ovary cancer xenograft model.  相似文献   

14.
为了解苦槛蓝(Myoporum bontioides)的化学成分,采用色谱分离法从叶中分离得到11个化合物,分别鉴定为:5,7,3’-三羟基-4’-甲氧基黄酮(1)、3,5,7,4’-四羟基-3’-甲氧基黄酮(2)、5,7,4’-三羟基-3’,5’-二甲氧基黄酮(3)、木犀草素(4)、山奈酚(5)、鼠李黄素(6)、5,7-二羟基二氢黄酮(7)、7,4’-二羟基二氢黄酮(8)、5,7,3’,4’-四羟基二氢黄酮(9)、5-O-乙酰基-3,7,3’,4’-四羟基二氢黄酮(10)和7-甲氧基香橙素(11)。除化合物4、7、11之外,其他化合物均为首次从苦槛蓝叶中分离得到。菌丝生长速率法测试表明化合物4、7~9和11对荔枝霜疫霉菌具有较好的抑菌活性。  相似文献   

15.
Lithospermum (Boraginaceae) comprises approximately 40 species in both the Old and New Worlds, with a center of diversity in the southwestern United States and Mexico. Using ten cpDNA regions, a phylogeny of Lithospermum and related taxa was reconstructed. Lithospermum (including New World and Old World species) and related New World members of Lithospermeae form a monophyletic group, with Macromeria, Onosmodium, Nomosa, Lasiarrhenum, and Psilolaemus nested among species of Lithospermum. New World Lithospermeae also is a monophyletic group, with Eurasian species of Lithospermum sister to this group. Because Lithospermum is not monophyletic without the inclusion of the other New World genera, species from these genera are transferred to Lithospermum, and appropriate nomenclatural changes are made. New combinations are Lithospermum album, Lithospermum barbigerum, Lithospermum dodrantale, Lithospermum exsertum, Lithospermum helleri, Lithospemum leonotis, Lithospermum notatum, Lithospermum oaxacanum, Lithospermum pinetorum, Lithospermum rosei, Lithospermum trinverium, and Lithospermum unicum; new names are Lithospermum chiapense, Lithospermum johnstonii, Lithospermum macromeria, Lithospermum onosmodium, Lithospermum rzedowskii, and Lithospermum turneri.  相似文献   

16.

The sorptive behavior of bacteria—iron oxide composites was investigated in batch metal sorption assays using ferrihydrite in isolation (0.13 and 0.14 g/L ferrihydrite in cadmium and lead systems, respectively) as well as in combination with Bacillus subtilis (0.25 g/L adsorbent mixture) and Escherichia coli (0.27 g/L adsorbent mixture). A pH range from 3.0 to 6.5 was studied using total metal concentrations of 1.0 × 10 ? 4.0 and 3.2 × 10 ? 5 M with adsorbent mixtures proportioned on a 1:1 mass/volume basis. The log of the apparent surface complex formation constants (log K S M ) and sorption capacity (S max ) values were determined by fitting the experimental data to one-site Langmuir sorption isotherms. The one-site model effectively described the sorption data (r 2 > 0.9), where Cd 2 + exhibited somewhat lower sorption affinities (log K S M = ?3 for ferrihydrite, ?1.7 for B. subtilis–ferrihydrite, and ?1.1 for E. coli–ferrihydrite) than Pb 2 + (log K S M = ?0.9 for ferrihydrite, ? 0.2 forB. subtilis–ferrihydrite, and –0.1 for E. coli–ferrihydrite). The corresponding S max values for Cd 2 + and Pb 2 + on ferrihydrite were 0.78 mmole/g and 1.34 mmole/g, respectively. For the B. subtilis–ferrihydrite composites, Cd 2 + and Pb 2 + S max values were lower at 0.29 mmole/g and 0.5 mmole/g, respectively. Similar values were determined for the E. coli–ferrihydrite composites (0.15 mmole/g and 0.68 mmole/g for Cd 2 + and Pb 2 + , respectively). The sorption of Cd 2 + and Pb 2 + by each of the sorbent systems exhibited a strong dependence on pH with sorption edges in the range of pH 4.0 to 7.3. The observed S max of the composites were lower than values predicted upon available site additivity (Cd 2 + B. subtilis ?ferrihydrite : 0.29 mmole/g (observed) < 0.57 mmole/g (calculated); Cd 2 + E. coli ?ferrihydrite : 0.15 mmole/g (observed) < 0.44 mmole/ g (calculated); Pb 2 + B. subtilis ?ferrihydrite : 0.5 mmole/g (observed) < 0.805 mmole/g (calculated); Pb 2 + E. coli –ferrihydrite : 0.68 mmole/g (observed) < 0.775 mmole/g (calculated)), implying that a masking of reactive surface sites by attachment had occurred between the bacteria and ferrihydrite. Electrophoretic mobility analysis indicated that the ferrihydrite surface properties dominate the net surface charge for each composite system with lesser contributions from the bacteria.  相似文献   

17.
ABSTRACT

A new isoflavone derivative compound 1 (psoralenone) was isolated from soybean inoculated with a marine fungus Aspergillus terreus C23-3, together with seven known compounds including isoflavones 26, butyrolactone I (7) and blumenol A (8). Their structures were elucidated by MS, NMR, and ECD. Psoralenone displayed moderate in vitro anti-inflammatory activity in the LPS-induced RAW264.7 cell model. Compound 2 (genistein) showed moderate acetylcholinesterase (AChE) inhibitory activity whereas compounds 2, 5 (biochanin A), 6 (psoralenol), and 7 exhibited potent larvicidal activity against brine shrimp. Compounds 3 (daidzein), 4 (4?-hydroxy-6,7-dimethoxyisoflavone), and 57 showed broad-spectrum anti-microbial activity, and compound 7 also showed moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity.  相似文献   

18.
Abstract

In order to approach the detailed structure-function relationships of aromatase, we studied the inhibitory and inactivatory potencies of several steroidal androstenedione analogues (1: 4-hydroxyandrostenedione, 2: 4-acetoxyandrostenedione and 3: 7α-(4'-amino)phenylthio-4-androstene-3, 17-dione) and non-steroidal imidazole derivatives (4: ketoconazole, 5: miconazole and 6: fadrozole) on equine aromatase in placental microsomes, a well established mammalian model. Human placental microsomes and the purified enzyme from equine testis were also used to compare inhibition by 1 and 2. In equine microsomes, all compounds tested exhibited a competitive inhibition, with Ki values of 4.1, 26 and 1.8 nM for 1, 2 and 3, and of 2400, 1.4 and 4 nM for 4, 5, and 6, respectively. The Km for androstenedione, the substrate mainly used in these studies, was 1.8 ± 0.13 nM. The three non-steroidal derivatives did not inactivate equine aromatase, but 1 and 2 acted as comparable inactivators to a much higher degree than 3. Compound 1 inhibited in a similar manner (89–94%) purified or equine and human microsomal aromatases, whereas 2 inhibited microsomal aromatase more efficiently in the horse than in man (92% and 33% inhibition, respectively). There was only a 40% inhibition with 2 on the purified equine enzyme, which is no more in the natural membrane environment. The comparisons between equine and human microsomal aromatases allow precise functional and structural differences to be observed with these enzymes.  相似文献   

19.
Summary Two plant communities, both dominated by Carex sempervirens but growing at different altitudes of the Northern Calcareous Alp region (IS: 600 m; KS: 1200 m) and one Carex ferruginea — dominated community (KC: 1200 m) are compared as to changes in dry matter, nitrogen, phosphorus, and potassium content of living and dead overground and underground phytomass.The soils of the montanic sites KS and KC are better provided with water and the three nutrients than that of the prealpine site IS. KC has the highest potassium content in the soil and in the phytomass.The dry matter increase (g/m2) of the living overground phytomass during the growing season is about 200 in IS, 360 in KS, and 340 in KC with maxima of 365 in IS, 550 in KS and 375 in KC.The increase of dead overground phytomass is highest in KS, indicating that the total annual overground production exceeds the mere increase in living parts. Furthermore, there is an increase of underground phytomass in KS and KC. The average ratio of total underground/living overground phytomass is 4.6 in IS, 3.7 in KS, but 7.5 in KC.The annual fluctuation of nitrogen (g/m2) in the living overground phytomass increases from 2.5 in IS to 3.8 in KS and to 5.9 in KC. For KS and KC these values approach the nitrogen mineralization values of the soils observed during the growing season. There is an obvious increase of nitrogen in the underground phytomass of KS and KC toward the end of the growing season. It is concluded that in KC, there is a more pronounced annual oscillation of nitrogen between overground and underground phytomass, which is not observed in IS, and which in KS is intermediate.  相似文献   

20.
Mutilin (4) and deoxy analogues 2 and 3 are biosynthetic precursors of pleuromutilin (1) in the later stage of biosynthesis. Precursors 2 and 3 are required for studies on the oxygenation steps in biosynthesis, and were synthesized from readily available 1 via 4 by deoxygenation of the hydroxy groups. Feeding experiments with the 2H-labeled precursors confirmed their microbial conversion into 1.  相似文献   

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