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1.
Ketan Shah Iqbal Mehdi A. W. Khan V. C. Vora 《Applied microbiology and biotechnology》1980,10(1-2):167-169
Summary
Arthrobacter
simplex, Serratia
marcescens, Fusarium and Mycobacterium were tested for their ability to transform phytosterol to Androsta 1, 4 diene 3, 17 dione (ADD). Arthrobacter
simplex ATCC 6946 was found to be more efficient than the other species tested. 相似文献
2.
The kinetics of the cellular uptake of iron-transferrin complex was studied in L1210 murine leukemia cells and rat reticulocytes using 125I-transferrin. Saturation of transferrin with iron was necessary for optimal uptake. Following the incubation of cells with the radiolabeled complex a biphasic pattern of uptake was observed. The initial phase was rapid and relatively temperature-independent and was not altered by ethylamine, an inhibitor of transglutaminase activity which is necessary for receptor-mediated endocytosis. This phase was considered to result from receptor-ligand interaction which could be reversed to a great degree by replacement with unlabeled transferrin. A plateau was then reached, indicating a saturation of receptors. After 30 min a second phase of uptake was indicated by the second rise in the curve. This phase was slow, relatively temperature-dependent and could be abolished by ethylamine. It was interpreted as evidence of internalization of the ligand. Analysis of the data from competition studies with unlabeled transferrin indicated that the first phase might itself comprise a reversible and an irreversible step with a ratio of 5 to 1.4 for bound transferrin. Thus, the cellular uptake of iron-transferrin complex may consist of a reversible ligand-receptor interaction. Conformational changes may render this interaction irreversible and the internalization of the ligand may then follow. 相似文献
3.
Mehdi Adib Fariba Peytam Reihaneh Shourgeshty Maryam Mohammadi-Khanaposhtani Mehdi Jahani Somaye Imanparast Mohammad Ali Faramarzi Bagher Larijani Ali Akbar Moghadamnia Ensieh Nasli Esfahani Fatemeh Bandarian Mohammad Mahdavi 《Bioorganic & medicinal chemistry letters》2019,29(5):713-718
Twenty three fused carbazole–imidazoles 6a–w were designed, synthesized, and screened as new α-glucosidase inhibitors. All the synthesized fused carbazole-imidazoles 6a-w were found to be more active than acarbose (IC50?=?750.0?±?1.5?µM) against yeast α-glucosidase with IC50 values in the range of 74.0?±?0.7–298.3?±?0.9?µM. Kinetic study of the most potent compound 6v demonstrated that this compound is a competitive inhibitor for α-glucosidase (Ki value?=?75?µM). Furthermore, the in silico studies of the most potent compounds 6v and 6o confirmed that these compounds interacted with the key residues in the active site of α-glucosidase. 相似文献
4.
Ben Khalaf N De Muylder G Ratnam J Kean-Hooi Ang K Arkin M McKerrow J Chenik M 《Journal of biomolecular screening》2011,16(5):545-551
The use of a high-throughput technique to perform a pilot screen for Leishmania major protein disulfide isomerase (LmPDI) inhibitors identification is reported. In eukaryotic cells, protein disulfide isomerase (PDI) plays a crucial role in protein folding by catalyzing the rearrangement of disulfide bonds in substrate proteins following their synthesis. LmPDI displays similar domain structure organization and functional properties to other PDI family members and is involved in Leishmania virulence. The authors used a method based on the enzyme-catalyzed reduction of insulin in the presence of dithiothreitol. The screen of a small library of 1920 compounds was performed in a 384-well format and led to the identification of 27 compounds with inhibitory activity against LmPDI. The authors further tested the cytotoxicity of these compounds using Jurkat cells as well as their effect on Leishmania donovani amastigotes using high-content analysis. Results show hexachlorophene and a mixture of theaflavin monogallates inhibit Leishmania multiplication in infected macrophages derived from THP-1 cells, although the inhibitory effect on LmPDI enzymatic activity does not necessarily correlate with the antileishmanial activity. 相似文献
5.
Salehi Jouzani G Seifinejad A Saeedizadeh A Nazarian A Yousefloo M Soheilivand S Mousivand M Jahangiri R Yazdani M Amiri RM Akbari S 《Canadian journal of microbiology》2008,54(10):812-822
The characterization of nematode-effective strains and cry genes in the Iranian Bacillus thuringiensis (Bt) collection (70 isolates) is presented. Characterization was based on PCR analysis using 12 specific primers for cry5, cry6, cry12, cry13, cry14, and cry21 genes encoding proteins active against nematodes, crystal morphology, and protein band patterns as well as their nematicidal activity on root-knot nematode (Meloidogyne incognita) and two free-living nematodes (Chiloplacus tenuis and Acrobeloides enoplus). PCR results with primers for these genes showed that 22 isolates (31.5%) contain a minimum of one nematode-active cry gene. Strains containing the cry6 gene were the most abundant and represent 22.8% of the isolates. Bt strains harboring cry14 genes were also abundant (14.2%). cry21 and cry5 genes were less abundant, found in 4.2% and 2.8% of the strains, respectively. In total, six different nematode-active cry gene profiles were detected in this collection. Four isolates did not show the expected PCR product size for cry5, cry6, and cry21 genes; they might contain potentially novel insecticidal crystal protein genes. Twenty-two Bt isolates containing nematode-active cry genes were selected for preliminary bioassays on M. incognita. Based on these bioassays, four isolates were selected for detailed bioassays. Isolates YD5 and KON4 at 2 x 10(8) CFU/mL concentrations showed 77% and 81% toxicity on M. incognita, respectively. The free-living nematodes C. tenuis and A. enoplus were more susceptible and the highest mortality was observed within 48 h of incubation at all of the concentrations tested. Maximum mortality was recorded for isolates SN1 and KON4 at 2 x 10(8) CFU/mL concentrations and resulted in 68% and 77% adults deaths of C. tenuis and 68% and 72% for A. enoplus, respectively. Our results showed that PCR is a useful technique for toxicity prediction of nematicidal Bt isolates. 相似文献
6.
PD98059 and U0126 are organic compound inhibitors frequently used to block the activity of the MEK-1/2 protein kinase. In the present work, promoter activation analyses of xanthine oxidoreductase (XOR) in epithelial cells uncovered the unexpected opposite effect of these inhibitors on activation of XOR. Activation of an XOR-luciferase fusion gene was studied in stably transfected epithelial cells. The XOR reporter gene was activated by the epidermal growth factors (EGF), prolactin, and dexamethasone and by the acute phase cytokines (APC) IL-1, IL-6, and TNFalpha as previously reported for its native gene, and insulin further stimulated activation induced with acute phase cytokines or growth factors. Activation of the proximal promoter was blocked by inhibitors of the glucocorticoid receptor (GR), p38 MAP kinase, and U0126. Unexpectedly, PD98059 activated the promoter and significantly enhanced expression induced by insulin, APC, or growth factors. Analysis of the XOR upstream DNA and proximal promoter revealed primary roles for the GR and STAT3 in mediating the effects of PD98059 on XOR activation and protein complex formation with the promoter. STAT3 phosphotyrosine-705 was rapidly induced by PD98059, dexamethasone, and insulin. XOR activation by PD98059, dexamethasone, or insulin was superinduced by a constitutively active derivative of STAT3, while a dominant negative derivative of STAT3 blocked the enhancing effect of PD98059 on XOR activation. These data demonstrate a previously unrecognized effect of PD98059 on STAT3 and the GR that could have unanticipated consequences when used to infer the involvement of the MEK-1/2 protein kinase. 相似文献
7.
Matts RL Brandt GE Lu Y Dixit A Mollapour M Wang S Donnelly AC Neckers L Verkhivker G Blagg BS 《Bioorganic & medicinal chemistry》2011,19(1):684-692
Several Hsp90 modulators have been identified including the N-terminal ligand geldanamycin (GDA), the C-terminal ligand novobiocin (NB), and the co-chaperone disruptor celastrol. Other Hsp90 modulators elicit a mechanism of action that remains unknown. For example, the natural product gedunin and the synthetic anti-spermatogenic agent H2-gamendazole, recently identified Hsp90 modulators, manifest biological activity through undefined mechanisms. Herein, we report a series of biochemical techniques used to classify such modulators into identifiable categories. Such studies provided evidence that gedunin and H2-gamendazole both modulate Hsp90 via a mechanism similar to celastrol, and unlike NB or GDA. 相似文献
8.
Naima Maouche Nadia Ktari Idriss Bakas Najla Fourati Chouki Zerrouki Mahamadou Seydou François Maurel Mohammed Mehdi Chehimi 《Journal of molecular recognition : JMR》2015,28(11):667-678
A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4‐hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co‐exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
Davoud Nouri Inanlou Bagher Yakhchali Hossein Khanahmad Mossa Gardaneh Hesam Movassagh Reza Ahangari Cohan Mehdi Shafiee Ardestani Reza Mahdian Sirous Zeinali 《Biotechnology letters》2010,32(11):1615-1621
We have developed an integrase-defective lentiviral (LV) vector in combination with a gene-targeting approach for gene therapy
of β-thalassemia. The β-globin gene-targeting construct has two homologous stems including sequence upstream and downstream
of the β-globin gene, a β-globin gene positioned between hygromycin and neomycin resistant genes and a herpes simplex virus
type 1 thymidine kinase (HSVtk) suicide gene. Utilization of integrase-defective LV as a vector for the β-globin gene increased the number of selected clones
relative to non-viral methods. This method represents an important step toward the ultimate goal of a clinical gene therapy
for β-thalassemia. 相似文献
10.
(Z)-4',5'-Didehydro-5'-deoxy-5'-fluoroadenosine (I), 5'-deoxy-5'-difluoroadenosine (II), and 4',5'-didehydro-5'-deoxy-5'-fluoroarabinosyl-adenosine (III) are inhibitors of rat liver S-adenosyl-L-homocysteine hydrolase. Compounds I and II are time-dependent and irreversible inhibitors of the enzyme. Both I and II are oxidized by E.NAD to produce E.NADH, and fluoride anion is formed in the inactivation reaction (0.7 to 1.0 mole fluoride/mole of enzyme subunit, and 1.7 moles fluoride/mole of enzyme subunit from I and II, respectively). The enzyme is stoichiometrically labeled with [8-3H]-I, but the label is lost upon denaturation of the protein either with or without treatment of the labeled complex with sodium borohydride. The compound III, the arabino derivative of I, is a competitive inhibitor of the enzyme. The mechanism of the inhibition of S-adenosyl-L-homocysteine hydrolase by these inhibitors is discussed. 相似文献