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1.
2.
The study was devoted to the synthesis of pentyl glucosides (PenGn) and isopentyl glucosides (Iso-PenGn) by transglycosylation using recombinant cyclodextrin glycosyltransferase from Bacillus circulans A11, β-cyclodextrin as a glucosyl donor and 1-pentanol and isopentanol as acceptors. TLC and MS analysis indicated at least 3 products which were in accordance with PenGn and IsoPenGn having glucose, maltose and maltotriose attached to the alkyl groups of both alcohols. Two products of each glucoside were purified by preparative TLC and their structures were identified by NMR technique to be pentyl-α-D-glucopyranoside (PenG1), pentyl-α-D-maltopyranoside (PenG2), isopentyl-α-D-glucopyranoside (IsoPenG1) and isopentyl- α-D-maltopyranoside (IsoPenG2). The effect of water-in-hexadecane emulsion on emulsion-forming properties showed that PenG2 had the highest emulsifying activity. Adding PenG2 to the insoluble Corynebacterium glutamicum amylomaltase from Escherichia coli transformants (A406R), helped to perform it to more soluble conformation. Moreover, it was found that PenG1,2 exhibited a higher antibacterial activity against E. coli ATCC 25922 than that of IsoPenG1,2. Hence, the biological properties of the synthesized products may be useful for their applications as emulsifying, solubilizing and antibacterial agents.  相似文献   

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4.
α-Tocopheryl phosphate (α-TP), a water-soluble analogue of α-tocopherol, is found in humans, animals, and plants. α-TP is resistant to both acid and alkaline hydrolysis and may exert its own function in this form in vivo. In this study, the uptake, hydrolysis, and antioxidant action of α-TP were measured using α-TP with a deuterated methyl group, CD(3), at position 5 of the chroman ring (α-TP(CD3)). The hydrolysis of α-TP(CD3) was followed by measuring α-tocopherol containing the CD(3) group, α-T(CD3), in comparison to unlabeled α-tocopherol, α-T(CH3). α-TP(CD3) was incubated with cultured cells, and the intracellular α-T(CD3) formed was measured with HPLC-ECD and GC-MS. α-TP(CD3) was also administered to mice for 4 weeks by mixing in the diet, and α-T(CD3) was measured in plasma, liver, brain, heart, and testis to compare with endogenous unlabeled α-T(CH3). It was found that α-TP(CD3) was taken in and hydrolyzed readily to α-T(CD3) in cultured cells and in mice. The hydrolysis of α-TP(CD3) in cell culture medium was not observed. α-TP protected primary cortical neuronal cells from glutamate-induced cytotoxicity, and α-TP given to mice reduced the levels of lipid peroxidation products in plasma and liver. These results suggest that α-TP is readily hydrolyzed in vivo to α-T, which acts as an antioxidant, and that α-TP may be used as a water-soluble α-T precursor in intravenous fluids, in eye drops, or as a dietary supplement.  相似文献   

5.
Classical cadherins play a crucial role in establishing intercellular adhesion, regulating cortical tension, and maintaining mechanical coupling between cells. The mechanosensitive regulation of intercellular adhesion strengthening depends on the recruitment of adhesion complexes at adhesion sites and their anchoring to the actin cytoskeleton. Thus, the molecular mechanisms coupling cadherin-associated complexes to the actin cytoskeleton are actively being studied, with a particular focus on α-catenin and vinculin. We have recently addressed the role of these proteins by analyzing the consequences of their depletion and the expression of α-catenin mutants in the formation and strengthening of cadherin-mediated adhesions. We have used the dual pipette assay to measure the forces required to separate cell doublets formed in suspension. In this commentary, we briefly summarize the current knowledge on the role of α-catenin and vinculin in cadherin-actin cytoskeletal interactions. These data shed light on the tension-dependent contribution of α-catenin and vinculin in a mechanoresponsive complex that promotes the connection between cadherin and the actin cytoskeleton and their requirement in the development of adhesion strengthening.  相似文献   

6.
The binding of [3H]progesterone and [3H]16,17-cycloalkanoprogesterones to proteins from rat, rabbit, and human uteri and other organs was studied. We found that 16,17-cycloalkanoprogesterone derivatives display affinities for the uterine progesterone receptors comparable with that of the natural hormone and no substantial species differences in the affinity. Rabbit uterus was found to have no proteins distinct from the progesterone receptor that specifically bind [3H]16,17-cycloalkanoprogesterones. At the same time, in the human uterus, we found another protein that binds some of these progesterone derivatives; it turned out to be similar to the protein from rat uterus. A similar protein with the same selectivity and affinity for steroids was also found in rat and human kidneys. Blood serum, liver, lung, and a number of other tissues were found to contain a protein of the third type that binds the same 16,17-cycloalkanoprogesterones and exhibits submicromolar K d values for these steroids and a very low affinity for progesterone. We speculated that the introduction of a bulky substituent adjacently to the 17-side chain of progesterone could result in a change in the general biodynamics of the derivative including its transport, uptake, and accumulation in tissues, which may determine the selectivity of its effect.  相似文献   

7.

Background

Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder for which new diagnostic and therapeutic approaches are required. Hallmarks of COPD are matrix destruction and neutrophilic airway inflammation in the lung. We have previously described two tri-peptides, N-α-PGP and PGP, which are collagen fragments and neutrophil chemoattractants. In this study, we investigate if N-α-PGP and PGP are biomarkers and potential therapeutic targets for COPD.

Methods

Induced sputum samples from COPD patients, healthy controls and asthmatics were examined for levels of N-α-PGP and PGP using mass spectrometry and for the ability to generate PGP de novo from collagen. Proteases important in PGP generation in the lung were identified by the use of specific inhibitors in the PGP generation assay and by instillation of proteases into mouse lungs. Serum levels of PGP were compared between COPD patients and controls.

Results

N-α-PGP was detected in most COPD sputum samples but in no asthmatics or controls. PGP was detected in a few controls and in all COPD sputum samples, where it correlated with levels of myeloperoxidase. COPD sputum samples had the ability to generate N-α-PGP and PGP de novo from collagen. PGP generation by COPD sputum was blocked by inhibitors of matrix metalloproteases (MMP''s) 1 and 9 and prolyl endopeptidase. MMP''s 1 and 9 and prolyl endopeptidase acted synergistically to generate PGP in vivo when instilled into mouse lungs. Serum levels of PGP were also significantly higher in COPD patients than in controls

Conclusion

N-α-PGP and PGP may represent novel diagnostic tests and biomarkers for COPD. Inhibition of this pathway may provide novel therapies for COPD directed at the chronic, neutrophilic, airway inflammation which underlies disease progression.  相似文献   

8.
Previous studies have shown that breast tissues and breast cell lines convert progesterone (P) to 5α-dihydroprogesterone (5αP) and 3α-dihydroprogesterone (3αHP) and that 3αHP suppresses, whereas 5αP promotes, cell proliferation and detachment. The objectives of the current studies were to determine if the 5αP- and 3αHP-induced changes in cell numbers are due to altered rates of mitosis and/or apoptosis, and if 3αHP and 5αP act on tumorigenic and non-tumorigenic cells, regardless of estrogen (E) and P receptor status. The studies were conducted on tumorigenic (MCF-7, MDA-MB-231, T47D) and non-tumorigenic (MCF-10A) human breast cell lines, employing several methods to assess the effects of the hormones on cell proliferation, mitosis, apoptosis and expression of Bcl-2, Bax and p21. In all four cell lines, 5αP increased, whereas 3αHP decreased cell numbers, [3H]thymidine uptake and mitotic index. Apoptosis was stimulated by 3αHP and suppressed by 5αP. 5αP resulted in increases in Bcl-2/Bax ratio, indicating decreased apoptosis; 3αHP resulted in decreases in Bcl-2/Bax ratio, indicating increased apoptosis. The effects of either 3αHP or 5αP on cell numbers, [3H]thymidine uptake, mitosis, apoptosis, and Bcl-2/Bax ratio, were abrogated when cells were treated simultaneously with both hormones. The expression of p21 was increased by 3αHP, and was unaffected by 5αP. The results provide the first evidence that 5αP stimulates mitosis and suppresses apoptosis, whereas 3αHP inhibits mitosis and stimulates apoptosis. The opposing effects of 5αP and 3αHP were observed in all four breast cell lines examined and the data suggest that all breast cancers (estrogen-responsive and unresponsive) might be suppressed by blocking 5αP formation and/or increasing 3αHP. The findings further support the hypothesis that progesterone metabolites are key regulatory hormones and that changes in their relative concentrations in the breast microenvironment determine whether breast tissues remain normal or become cancerous.  相似文献   

9.
The gonads are known to produce numerous hormones and also neurotrophins and their receptors. Here we demonstrate expression of glial-cell-line-derived neurotrophic factor (GDNF) family ligands and related receptors in adult mice gonads by in situ hybridization. GDNF mRNA was expressed in the ovary, but was not detectable in testis. Neurturin (NTN), another ligand in this family, gave rise to strong mRNA hybridization signals in a mosaic pattern in the seminiferous tubules of the testis at stages IX-XII and I-II of the cycle. NTN mRNA signals were also found in uterus and the oviduct. In testis, the transducing receptor RET as well as GDNF receptor alpha-1 (GFR)alpha-1 and GFRalpha-2 were distributed in complementary and overlapping patterns, the former at stages XI-XII-I and the latter at stages VII and VIII. GFRalpha-3 could not be detected. Expression of these trophic molecules suggests involvement of GDNF family ligands and related receptor components in reproduction.  相似文献   

10.
Selective acid-catalysed methanolysis of 2,3,2′,3′-tetra-O-benzyl-4,6:4′,6′-di-O-benzylidene-α,α-trehalose yielded the monobenzylidene derivative, which was converted into the 4,6-dimesylate. Selective nucleophilic displacement of the primary sulphonyloxy group then gave 2,3-di-O-benzyl-6-deoxy-6-fluoro-4-O-mesyl-α-d-glucopyranosyl 2,3-di-O-benzyl-4,6-O-benzylidene-α-d-glucopyranoside. Removal of the protecting groups then yielded 6-deoxy-6-fluoro-α,α-trehalose. In addition, 6-deoxy-6-fluoro-4-O-mesyl-α,α-trehalose and a derivative of 4-chloro-4,6-dideoxy-6-fluoro-α-d-galactopyranosyl α-d-glucopyranoside were also prepared from the same substrate. Iodide displacement of 2,3-di-O-benzyl-4,6-di-O-mesyl-α-d-glucopyranosyl 2,3-di-O-benzyl-4,6-di-O-mesyl-α-d-glucopyranoside afforded the 6-iodide and 6,6′-di-iodide in yields of 31 and 36%, respectively. Similarly, the 6-azide and 6,6′-diazide were isolated in yields of 17 and 21%, respectively.  相似文献   

11.
The 3α,5α- and 3α,5β-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone enhance GABAergic neurotransmission and produce inhibitory neurobehavioral and anti-inflammatory effects. Despite substantial information on the progesterone derivative (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP, allopregnanolone), the physiological significance of the other endogenous GABAergic neuroactive steroids has remained elusive. Here, we describe the validation of a method using gas chromatography–mass spectrometry to simultaneously identify serum levels of the eight 3α,5α- and 3α,5β-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone. The method shows specificity, sensitivity and enhanced throughput compared to other methods already available for neuroactive steroid quantification. Administration of pregnenolone to rats and progesterone to women produced selective effects on the 3α,5α- and 3α,5β-reduced neuroactive steroids, indicating differential regulation of their biosynthetic pathways. Pregnenolone administration increased serum levels of 3α,5α-THP (+1488%, p < 0.001), (3α,5α)-3,21-dihydroxypregnan-20-one (3α,5α-THDOC, +205%, p < 0.01), (3α,5α)-3-hydroxyandrostan-17-one (3α,5α-A, +216%, p < 0.001), (3α,5α,17β)-androstane-3,17-diol (3α,5α-A-diol, +190%, p < 0.01). (3α,5β)-3-hydroxypregnan-20-one (3α,5β-THP) and (3α,5β)-3-hydroxyandrostan-17-one (3α,5β-A) were not altered, while (3α,5β)-3,21-dihydroxypregnan-20-one (3α,5β-THDOC) and (3α,5β,17β)-androstane-3,17-diol (3α,5β-A-diol) were increased from undetectable levels to 271 ± 100 and 2.4 ± 0.9 pg ± SEM, respectively (5/8 rats). Progesterone administration increased serum levels of 3α,5α-THP (+1806%, p < 0.0001), 3α,5β-THP (+575%, p < 0.001), 3α,5α-THDOC (+309%, p < 0.001). 3α,5β-THDOC levels were increased by 307%, although this increase was not significant because this steroid was detected only in 3/16 control subjects. Levels of 3α,5α-A, 3α,5β-A and pregnenolone were not altered. This method can be used to investigate the physiological and pathological role of neuroactive steroids and to develop biomarkers and new therapeutics for neurological and psychiatric disorders.  相似文献   

12.
The reduction of 3-ethylenedioxy-7-oximino-5-androsten-17β-yl acetate and of its 17β-tetrahydropyranyl ether analog with sodium in ethanol, followed by thin-layer chromatography, allowed the isolation of the corresponding 17β-hydroxy- and 17β-tetrahydropyranyioxy-5-en-7β- and 7α-amines which were also characte-rized as 7-acetamides. The acylation of the two epimeric 17β-hydroxy-5-en-7-amines with succinic anhydride followed by selective saponification of the 17β-hemisuccinate group and diazomethane esterification, gave the corresponding 17β-hydroxy-5-en-7β- and 7α-hemisuccinamido methyl esters characterized also as 17β-acetates. On the other hand, the acylation of the two 17β-tetrahydropyranyl-oxy-5-en-7-amines with the acid chloride of terephthalic acid monomethyi ester led to the more rigid 7β- and 7α-terephthalamido methyl ester side-chains. The acidolysis of the 3-ethyleneketal protecting group of the preceding 5-en-7-N-acyl derivatives regenerated the 4-en-3-oxo function while the 17β-tetrahydropyranyl ether group was cleaved simultaneously into the 17β-alcohol. The four desired 7β- and 7α-hemisuccinamido- and terephthalamido carboxylic side-chain derivatives of 17β-hydroxy-4-androsten-3-one (testosterone) were finally obtained by saponification of the corresponding methyl esters.  相似文献   

13.
14.
Interest in the structural requirements of a sterol or bile acid for maximal activity by an hepatic microsomal steroid 12α-hydroxylase prompted the preparation of 5α-cholestane-3α, 7α, 25-triol and 5α-analogs of 3α, 7α-dihydroxy-5β-cholane-24-carboxylic acid. Methyl 3α, 7α-dihydroxy-5β-cholane-24-carboxylate derived from methyl chenodeoxycholate via the Arndt-Eistert reaction was allomerized with Raney nickel in boiling p-cymene to provide a number of products of which methyl 3,7-dioxo-5β- and 5α-cholane-24-carboxylates, methyl 3-oxo-7α-hydroxy-5β-and 5α-cholane-24-carboxylates, were identified. Reduction with K-Selectride of methyl 3-oxo-7α-hydroxy-5β-cholane-24-carboxylate, provided a high yield of methyl 3α, 7α-dihydroxy-5α-cholane-24-carboxylate. Treatment of this ester with an excess of methyl magnesium iodide afforded 5α-cholestane-3α, 7α, 25-triol. The products were characterized by thin-layer and gas liquid chromatography, proton resonance, infrared and mass spectrometry.  相似文献   

15.
In order to study the effect of glycosylation on its biological activities, and to develop IL-1α with less deleterious effects, recombinant human IL-1α was chemically coupled with N-acetylneuraminic acid (α1-6) galactose (Neu5Ac-Gal). Glycosylated IL-1α (Neu5Ac-Gal-IL-1α) was purified by anion-exchange chromatography and average number of carbohydrate molecules introduced per molecule of IL-1α was 2.5. Neu5Ac-Gal-IL-1α exhibited reduced activities about 1/15-fold compared to IL-1α in all the activities performed in vitro. Binding affinities of Neu5Ac-Gal-IL-1α to Type I and Type II IL-1 receptors were decreased to 1/15 and 1/10, respectively. Neu5Ac-Gal-IL-1α exhibited reduction in activities in vivo, including induction of serum amyloid A and NO$_x$, and down-regulation of serum glucose. However, Neu5Ac-Gal-IL-1α exhibited comparable activity to IL-1α in improvement of the recovery of peripheral white blood cells from myelosuppression in 5-fluorouracil-treated mice. In addition, tissue level of Neu5Ac-Gal-IL-1α was relatively high compared to IL-1α. These results indicate that coupling with Neu5Ac-Gal enabled us to develop neoIL-1α with selective activities in vivo. Published in 2004. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

16.
Schober  Andreas  Arumäe  Urmas  Saarma  Mart  Unsicker  Klaus 《Brain Cell Biology》2000,29(3):209-213
Glial cell line-derived neurotrophic factor (GDNF), an important factor for developing and lesioned pre- and postganglionic sympathetic neurons, and its congeners signal through a receptor complex consisting of the tyrosine kinase c-Ret and a lipid-anchored α receptor (GFRα-1-4). Using in situ hybridization we show now that the mRNA for GFRα-2 is abundant in the adult rat adrenal medulla and its chromaffin cells. Coexpression of c-Ret and GFRα-1 mRNA's is restricted to a scarce subpopulation of medullary sympathetic neurons. Both GFRα-1 and GFRα-2 mRNA's are associated with preganglionic nerve trunks in the adrenal cortex. It is conceivable therefore that GDNF and related factors may activate chromaffin and preganglionic Schwann cells through a GFR-α receptor in absence of c-Ret.  相似文献   

17.
Cell‐wall components are hydrolysed by numerous plant glycosidase and glycanase activities. We investigated whether plant enzymes also modify xyloglucan structures by transglycosidase activities. Diverse angiosperm extracts exhibited transglycosidase activities that progressively transferred single sugar residues between xyloglucan heptasaccharide (XXXG or its reduced form, XXXGol) molecules, at 16 μm and above, creating octa‐ to decasaccharides plus smaller products. We measured remarkably high transglycosylation:hydrolysis ratios under optimized conditions. To identify the transferred monosaccharide(s), we devised a dual‐labelling strategy in which a neutral radiolabelled oligosaccharide (donor substrate) reacted with an amino‐labelled non‐radioactive oligosaccharide (acceptor substrate), generating radioactive cationic products. For example, 37 μm [Xyl3H]XXXG plus 1 mm XXLG‐NH2 generated 3H‐labelled cations, demonstrating xylosyl transfer, which exceeded xylosyl hydrolysis 1.6‐ to 7.3‐fold, implying the presence of enzymes that favour transglycosylation. The transferred xylose residues remained α‐linked but were relatively resistant to hydrolysis by plant enzymes. Driselase digestion of the products released a trisaccharide (α‐[3H]xylosyl‐isoprimeverose), indicating that a new xyloglucan repeat unit had been formed. In similar assays, [Gal3H]XXLG and [Gal3H]XLLG (but not [Fuc3H]XXFG) yielded radioactive cations. Thus plants exhibit trans‐α‐xylosidase and trans‐β‐galactosidase (but not trans‐α‐fucosidase) activities that graft sugar residues from one xyloglucan oligosaccharide to another. Reconstructing xyloglucan oligosaccharides in this way may alter oligosaccharin activities or increase their longevity in vivo. Trans‐α‐xylosidase activity also transferred xylose residues from xyloglucan oligosaccharides to long‐chain hemicelluloses (xyloglucan, water‐soluble cellulose acetate, mixed‐linkage β‐glucan, glucomannan and arabinoxylan). With xyloglucan as acceptor substrate, such an activity potentially affects the polysaccharide’s suitability as a substrate for xyloglucan endotransglucosylase action and thereby modulates cell expansion. We conclude that certain proteins annotated as glycosidases can function as transglycosidases.  相似文献   

18.
The effects of 1α,25-dihydroxyvitamin D3, 24R,25-dihydroxyvitamin D3 and 1α,24R,25-trihydroxyvitamin D3 on active calcium and phosphate transport by rat duodenum were studied in vitamin D-deficient rats that either underwent sham surgery or were bilaterally nephrectomized. Both 1α, 25-dihydroxy- and 1α,24R,25-trihydroxyvitamin D3 markedly stimulated calcium and phosphate absorption with similar effects in shamoperated and nephrectomized rats. A 10-fold higher dose of 24R,25-dihydroxyvitamin D3 was required for an equivalent stimulation of absorption in sham-operated rats, and this compound had no effect on duodena from nephrectomized rats. These data provide the first evidence that 24R,25-dihydroxy- and 1α,24R,25-trihydroxyvitamin D3 can stimulate the active intestinal absorption of phosphate. The lack of response to 24R,25-dihydroxyvitamin D3 in nephrectomized rats confirms prior results which indicated that renal metabolism of this secosteroid to 1α,24,25-trihydroxyvitamin D3 is required for biological activity. In addition, we describe a simple bioassay technique which apparently reflects, with reasonable accuracy, the changes in duodenal calcium and phosphate absorption which occur under more rigorous short-circuited conditions and, in particular, can be used for screening putative 1α-hydroxyl analogs of vitamin D in nephrectomized rats.  相似文献   

19.
Interferon-α (IFN-α) genes have been cloned from a variety of animals, but information regarding crane IFN-α has not been reported to date. In this study, we cloned a full-length Red-crowned Crane interferon-α (crIFN-α) gene sequence consisting of a 486 bp partial 5′ UTR, 741 bp complete ORF and 559 bp partial 3′ UTR. This gene encodes a protein of 246 amino acids and shares 60 to 80% identity with avian IFN-α and less than 45% identity with mammalian IFN-α. The expression of crIFN-α with an N-terminal His-tag was investigated in Escherichia coli, and the protein was purified on a nickel column. To obtain activated proteins, crIFN-α inclusion bodies were renatured by dialysis. In vitro cytopathic inhibition assays indicated that the recombinant crIFN-α could inhibit the replication of vesicular stomatitis virus in chicken fibroblasts. These antiviral activities were abrogated by rabbit anti-crIFN-α antibodies in vitro. In addition, an immunofluorescence assay indicated that crIFN-α could be expressed in chicken fibroblasts and was primarily located in the cytoplasm. Taken together, our results suggest that the crIFN-α gene may play an important role in inhibiting the replication of viruses.  相似文献   

20.
《Carbohydrate research》1998,310(4):229-238
Eight positional isomers of 61,6m-di-O-α-d-mannopyranosyl-cyclomaltooctaose (γCD) (m=2–5) and 6-O-α-(n-O-α-d-mannopyranosyl)-d-mannopyranosyl-γCD (n=2, 3, 4, and 6) in a mixture of products from γCD and d-mannose by condensation reaction of α-mannosidase from jack bean were isolated by HPLC. The structures of four isomers of 6-O-α-(n-O-α-d-mannopyranosyl)-d-mannopyranosyl-γCD were elucidated by NMR spectroscopy. On the other hand, four positional isomers of 61,6m-di-O-α-d-mannopyranosyl-γCD were determined by LC–MS analysis of degree of polymerization of the branched oligosaccharides produced by enzymatic degradation with bacterial saccharifying α-amylase (BSA), and combination of BSA and glucoamylase. Similarly cyclomaltodextrin glucanotransferase also digested these isomers.  相似文献   

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