共查询到20条相似文献,搜索用时 15 毫秒
1.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):605-609
Abstract β-D-pentofuranonucleoside derivatives of 2-azidoadenine and 6-azidopurines have been synthesized. The azido-tetrazolo tautomerism observed on such nucleoside analogues has been studied. The compounds were tested for their activity against HIV and HBV but they did not show significant antiviral effect. 相似文献
2.
Abstract 3′-Deoxy-β-L-erythro- (3), 3′-deoxy-β-L-thero- (6), 2′-fluoro- (7) and 2′-azido-2′,3′-dideoxy-β-L-erythro- (10) pentofuranonucleoside derivatives of thymine have been synthesized and their antiviral properties examined. All these derivatives were stereospecifically prepared by glycosylation of thymine with a suitable peracylated 3-deoxy-L-erythro-pentofuranose sugar (1), followed by appropriate chemical modifications. The prepared compounds were tested for their activity against HIV, but they did not show an antiviral effect. 相似文献
3.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):861-863
Abstract β-D- and β-L-pentofuranonucleoside derivatives bearing 5-trifluoromethylcytosine as the base have been synthesized. The compounds were tested for their activity against HIV and HBV, but they did not show significant antiviral effect. 相似文献
4.
Sivak K. V. Stosman K. I. Muzhikyan A. A. Alexandrov A. G. Viktorov N. B. Vaulina D. D. Gomzina N. A. 《Russian Journal of Bioorganic Chemistry》2019,45(5):425-429
Russian Journal of Bioorganic Chemistry - The synthesis of two derivatives of lignan 4'-O-methylhonokiol (MH), i.e., 4'-methoxy-5-propyl-1,1'-biphenyl-2-ol (III) and... 相似文献
5.
Naoki Kashimura Kichitaro Kawaguchi 《Bioscience, biotechnology, and biochemistry》2013,77(8):1621-1624
Sequential oxidation and reduction of aryl 4, 6-O-benzylidene-β-d-glucosides with dimethyl sulfoxide-phosphorus pentoxide mixture (DMSO–P2O5) and sodium borohydride were carried out as a new means for the preparation of aryl β-d-mannopyranoside derivatives. p-Nitrophenyl 4, 6-O-benzylidene-β-d-mannopyranoside was obtained in 22% yield from the corresponding glucoside 3-O-acetate, whereas from the unprotected acetal, 4, 6-O-benzylidene acetals of the corresponding mannoside and alloside were isolated in the yields of 6.7 and 2.1%, respectively. Similarly, phenyl 4, 6-O-benzylidene β-d-mannoside, alloside, and altroside were obtained from the corresponding glucoside in 2.2, 0.8 and 2.1% yields, respectively. 相似文献
6.
Heller C Kühn MC Mülders-Opgenoorth B Schott M Willenberg HS Scherbaum WA Schinner S 《American journal of physiology. Endocrinology and metabolism》2011,301(5):E864-E872
The Wnt-signaling pathway regulates β-cell functions. It is not known how the expression of endogenous Wnt-signaling molecules is regulated in β-cells. Therefore, we investigated the effect of antidiabetic drugs and glucose on the expression of Wnt-signaling molecules in β-cells. Primary islets were isolated and cultured. The expression of Wnt-signaling molecules (Wnt-4, Wnt-10b, Frizzled-4, LRP5, TCF7L2) and TNFα was analyzed by semiquantitative PCR and Western blotting. Transient transfections were carried out and proliferation assays of INS-1 β-cells performed using [(3)H]thymidine uptake and BrdU ELISA. Insulin secretion was quantified. A knockdown (siRNA) of Wnt-4 in β-cells was carried out. Exendin-4 significantly increased the expression of Wnt-4 in β-cells on the mRNA level (2.8-fold) and the protein level (3-fold) (P < 0.001). The effect was dose dependent, with strongest stimulation at 10 nM, and it was maintained after long-term stimulation over 4 wk. Addition of exd-(9-39), a GLP-1 receptor antagonist, abolished the effect of exendin-4. Treatment with glucose, insulin, or other antidiabetic drugs had no effect on the expression of any of the examined Wnt-signaling molecules. Functionally, Wnt-4 antagonized the activation of canonical Wnt-signaling in β-cells. Wnt-4 had no effect on glucose-stimulated insulin secretion or insulin gene expression. Knocking down Wnt-4 decreased β-cell proliferation to 45% of controls (P < 0.05). In addition, Wnt-4 and exendin-4 treatment decreased the expression of TNFaα mRNA in primary β-cells. These data demonstrate that stimulation with exendin-4 increases the expression of Wnt-4 in β-cells. Wnt-4 modulates canonical Wnt signaling and acts as regulator of β-cell proliferation and inflammatory cytokine release. This suggests a novel mechanism through which GLP-1 can regulate β-cell proliferation. 相似文献
7.
Henrik M. Pfundheller Poul Nielsen Jesper Wengel 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1439-1442
Abstract The stereoselective synthesis of 3′-C-Allyluridine derivative 2 has been accomplished. This nucleoside was used as a key synthon for the synthesis of oligodeoxynucleotides containing 3′-C-(3-benzoyloxypropyl)thymidine (X) or bicyclo nucleoside (Y+Z) monomers. Preliminary thermal experiments are reported. 相似文献
8.
Gerhard Müller Markus Albers Gerhard He?ler? Thomas E. Lehmann Hiromi Okigami Masaomi Tajimi 《Journal of enzyme inhibition and medicinal chemistry》2013,28(4):309-312
Terephthalic acid based derivatives containing β- and γ-amino acid residues were prepared as antagonists of the leukocyte cell adhesion process that is mediated through the interaction of the very late antigen 4 (VLA-4) and the vascular cell adhesion molecule 1 (VCAM-1). The compounds 2, 10–12, 14, and 16–17 inhibited the adhesion in a cell based assay in the low and sub micromolar range. 相似文献
9.
10.
Monakhova M. V. Kubareva E. A. Romanova E. A. Semkina A. S. Naberezhnov D. S. Rao D. N. Zatsepin T. S. Oretskaya T. S. 《Russian Journal of Bioorganic Chemistry》2019,45(2):144-154
Russian Journal of Bioorganic Chemistry - Diketone DNA derivatives have been proposed to modify the guanidine group of Arg in proteins. The β-diketo group at the C2' atom of the sugar... 相似文献
11.
Twenty-five bacterial species were cultured in basal broth plus 1 of 19 different carbohydrates which were sterilized by Seitz filtration, autoclaving (112 C, 10 min), or exposure to 0.2% β-propiolactone (BPL). No significant differences were found either in the visual observations for acid and gas, pH, or titrable acidity determinations after 3 days of incubation with any of the three preparations tested. An effort was made to further determine the effect of BPL and heat on carbohydrates by assaying for glucose before and after treatment. Results indicated that glucose was not degraded by 0.2% BPL, however, it was shown that autoclave temperatures caused extensive degradation. Statistical treatment of the results from Warburg studies indicated that BPL-treated glucose showed no appreciable toxic effects, although the actual oxygen uptake was not as great as with Seitz- or autoclave-treated glucose. The application of the BPL sterilization process was discussed. 相似文献
12.
Malenkovskaya M. A. Shipilov D. A. Grachev M. K. 《Russian Journal of Bioorganic Chemistry》2020,46(1):71-76
Russian Journal of Bioorganic Chemistry - The synthesis of amphiphilic cationic β-cyclodextrin derivatives that contain the residues of some pharmacologically important acids have been... 相似文献
13.
Administration of β-phenylethylamine (PEA), the simplest endogenous neuroamine, and various methylated PEA derivatives including α-methyl PEA (amphetamine, AMP) elicits analgesia in mice. Five or 20 min after intraperitoneal PEA injection of as little as 6 mg/kg resulted in an increased latency response time (from 2.4 ± 0.4 to 8.5 ± 2.3 or 7.0 ± 3.0 s, respectively) to the thermal stimulus (hot-plate test), which reached statistical significance at the 15 mg/kg (20 min; 13.1 ± 0.4 s) or 25 mg/kg dose (5 min; 15.3 ± 4.1 s). This PEA effect, was dose-dependent (albeit non-linear: 6, 12, 15, 25, 50 and 100 mg/kg), reached the cut-off time of 45 s at the upper PEA dose (5 min), and it was consistently enhanced by pretreatment with the monoamine oxidase inhibitor pargyline (P). Methylated PEA derivatives (15 and 100 mg/kg dose) produced various degrees of analgesia (in decreasing order p-Me PEA > PEA > N,N-diMe PEA > N-Me PEA) which, likewise to PEA itself, were consistently increased by P and declined over time (mice tested 5, 20 and 60 min after amine injection); small but statistically significant o- and β-Me PEA antinociceptive effects (5 min) were observed only at the higher dose (in the presence of P for β-Me PEA). A small analgesic effect was observed after the administration of AMP (5 or 10 mg/kg) which failed, even after P, to reach statistically significance. Independent of the amine and concentration tested, individual compound’s antinociceptive properties were reliably increased by P (exception of AMP), decreased by reserpine (R) or haloperidol (H), and remained essentially unchanged after naloxone (N) administration suggesting the involvement of catecholamines, but not opioid peptides, in their observed analgesic effects. Injection of P + N produced results similar to those seen after P alone. Under the experimental conditions described neither P, R, H or N had any effects by themselves. These findings suggest additional understanding of the mechanism of action responsible for the analgesic effects of these amines would be of interest, leading further to controlled studies on their alleged usefulness as weight reducing agents and sport performance enhancers. 相似文献
14.
Two different artificial chaperone systems were evaluated in this work using either detergents or CDs as the stripping agents.
Upon dilution of urea-denatured α-amylase to a non-denaturing urea concentration in the presence of the capturing agent, complexes
of the detergent and non-native protein molecules are formed and thereby the formation of protein aggregates is prevented.
The so-called captured protein is unable to refold from the detergent-protein complex states unless a stripping agent is used
to remove the detergent molecules. Our results by fluorescence, UV, turbidity measurement, circular dichroism, surface tension
and activity assay indicated that the extent of refolding assistance was different due to different inter- and intra- molecular
interactions in the two different systems. However, the high activity recovery in the presence of detergents, as the stripping
agent, suggests that they can constitute suitable replacement for the more expensive and common stripping agent of cyclodextrins. 相似文献
15.
Masahiko Seki Tamon Moriya Kazuo Matsumoto 《Bioscience, biotechnology, and biochemistry》2013,77(11):3033-3038
(3S, 4R)-3-Methoxycarbonylamino-4-phenyl-4-butanolide (4a) was prepared from l-aspartic acid by stereoselective reduction of ethyl (*S)-3-methoxycarbonylamino-4-oxo-4-phenylbutyrate (3a). 相似文献
16.
John A. Secrist III Anita Shortnacy-Fowler L. Lee Bennett Jr. John A. Montgomery 《Nucleosides, nucleotides & nucleic acids》2013,32(5):1017-1029
Abstract A series of 8-substituted purine ribonucleosides were prepared from 2′, 3′, 5′-tri-O-acetyl-8-bromoadenosine and evaluated for cytotoxicity and antiviral activity. Four of these nucleosides (6b-9b) were significantly toxic to both HEp-2 and L1210 cells in culture but the most cytotoxic one (9b) was inactive against the P388 leukemia in mice. None of these nucleosides showed significant antiviral activity against Herpes Simplex 1 or 2, vaccinia, or influenza A. 相似文献
17.
Activity of β-glucuronidase in Root Tips of Different Types of Transgenic Sugar Beet Plants 总被引:1,自引:0,他引:1
S. Vitha J.P. Phillips J.S. Gartland K.M.A. Gartland K. Beneš M.C. Elliott 《Biologia Plantarum》1997,40(4):531-541
Expression of the -glucuronidase (GUS) reporter gene driven by the CaMV 35S, rolC, nos and mas promoters was assessed in the tips of 12 independent clones of transgenic sugar beet (Beta vulgaris) roots. Three questions were addressed: 1) expression pattern specific for a given promoter, 2) expression pattern variability, and 3) relationship between gene expression and cell differentiation. Characteristic patterns of tissue-specific expression were distinguished for each promoter. Striking differences, however, were found between some clones, bearing the same construct. Statistical analysis of the pattern variability proved that the variability is significantly lower within the construct than between constructs. rolC-GUS clones exhibited the lowest and CaMV 35S clones the highest pattern variability. Comparisons between the four promoters showed consistent GUS activity in areas playing a key role in tissue determination (the elongation zone) where cells switch from frequent mitosis and mostly isodiametrical growth, typical for the promeristem, to rapid elongation and differentiation. All of the clones were highly GUS-positive in the elongation zone of stele. Activity was commonly localised in the stele of the maturation zone for CaMV 35S, rolC and mas-GUS clones. CaMV 35S-GUS clones were highly active in the promeristem. 相似文献
18.
Christopher F. Spurney Hee-Jae Cha Arpana Sali Gouri S. Pandey Emidio Pistilli Alfredo D. Guerron Heather Gordish-Dressman Eric P. Hoffman Kanneboyina Nagaraju 《PloS one》2010,5(1)
Thymosin beta-4 (Tβ4) is a ubiquitous protein with many properties relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory mediators. We studied the effects of chronic administration of Tβ4 on the skeletal and cardiac muscle of dystrophin deficient mdx mice, the mouse model of Duchenne muscular dystrophy. Female wild type (C57BL10/ScSnJ) and mdx mice, 8–10 weeks old, were treated with 150 µg of Tβ4 twice a week for 6 months. To promote muscle pathology, mice were exercised for 30 minutes twice a week. Skeletal and cardiac muscle function were assessed via grip strength and high frequency echocardiography. Localization of Tβ4 and amount of fibrosis were quantified using immunohistochemistry and Gomori''s tri-chrome staining, respectively. Mdx mice treated with Tβ4 showed a significant increase in skeletal muscle regenerating fibers compared to untreated mdx mice. Tβ4 stained exclusively in the regenerating fibers of mdx mice. Although untreated mdx mice had significantly decreased skeletal muscle strength compared to untreated wild type, there were no significant improvements in mdx mice after treatment. Systolic cardiac function, measured as percent shortening fraction, was decreased in untreated mdx mice compared to untreated wild type and there was no significant difference after treatment in mdx mice. Skeletal and cardiac muscle fibrosis were also significantly increased in untreated mdx mice compared to wild type, but there was no significant improvement in treated mdx mice. In exercised dystrophin deficient mice, chronic administration of Tβ4 increased the number of regenerating fibers in skeletal muscle and could have a potential role in treatment of skeletal muscle disease in Duchenne muscular dystrophy. 相似文献
19.
S. Tam M. Holman R. S. Klein M. Mitsuya S. Broder 《Nucleosides, nucleotides & nucleic acids》2013,32(5-6):1109-1110
Abstract In this paper we report the synthesis of 2′,3′-dideoxy-9-dearaadenosine (2) and the corresponding 2′,3′-unsaturated- and 3′-deoxy- analogs, 6 and 8. These C-nucleosides are very stable towards acid and thus overcome one of the main drawbacks of 2′,3′-dideoxy-purine-nucleosides, such as the antiviral agent 2′,3′-dideoxyadenosine (ddA). However, evaluation of these compounds and some related 2′-deoxy derivatives (10-14) in the antiviral assay for the human immunodeficiency virus has revealed no significant activity. 相似文献
20.
Abstract 3′-O-Ethyl-4′-C-(hydroxymethyl)thymidine (5) was synthesized and converted into the phosphoramidite building block 8. Novel oligodeoxynucleotide analogues containing 4′-C-hydroxymethyl phosphodiester internucleoside linkages were synthesized on an automated DNA-synthesizer. The hybridization properties and enzymatic stability were studied on oligomers with one to four modifications. The 3′-end modified oligodeoxynucleotides were resistent towards 3′-exonuclease degradation and showed only moderate lowered affinity towards complementary DNA compared with oligodeoxynucleotides bearing modifications in the middle. 相似文献