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891.
Purified glucoamylase from Arachniotus citrinus was immobilized on polyacrylamide gel with 70% yield of immobilization. The immobilization improved the pH optima, temperature optima, values of K(m), V(max), and activation energy. Irreversible thermal denaturation studies of soluble and immobilized glucoamylase indicated that immobilization decreased the entropy and enthalpy of deactivation by magnitudes and made the immobilized glucoamylase thermodynamically more stable. 相似文献
892.
Usman H Hakim EH Harlim T Jalaluddin MN Syah YM Achmad SA Takayama H 《Zeitschrift für Naturforschung. C, Journal of biosciences》2006,61(3-4):184-188
A new flavanone, 7-hydroxy-5,6-dimethoxyflavanone (1), together with three other flavonoids, didymocarpin (2), 2',4'-dihydroxy-5',6'-dimethoxychalcone (3), and isodidymocarpin (4), had been isolated from the methanol extract of the tree bark of Cryptocarya costata. The structures of these compounds were determined based on spectral evidence, including UV, IR, 1-D and 2-D NMR, and mass spectra. Cytotoxic properties of compounds 1-4 were evaluated against murine leukemia P-388 cells. The chalcones 3 and 4 were found to have substantial cytotoxicity with IC50 of 5.7 and 11.1 microM, respectively. 相似文献
893.
Muzna Zahur Asma Maqbool Muhammad Irfan Muhammad Younas Khan Barozai Bushra Rashid Shiekh Riazuddin Tayyab Husnain 《Molecular Biology》2009,43(4):578-585
The 949 bp promoter fragment upstream from the translation initiation site of the GUSP gene encoding a universal stress protein was isolated from the genomic DNA of Gossypium arboreum. Some putative cis-acting elements involved in stress responses including E-box, ABRE, DPBF-box, and MYB-core elements were found in the promoter
region. In an Agrobacterium-mediated transient expression assay, strong activation of the GUSP full promoter region occurred in tobacco leaves following dehydration, abscisic acid, salt, heavy metal, gibberellic acid
and dark treatments. Deletion analysis of the promoter revealed that the dehydration, abscisic acid and salt responses were
affected by the deletion between −208 and −949 bp and showed 2–4-fold induction. However, in response to dark, gibberellic
acid and heavy metals the induction was only 2-fold. These findings further our understanding of the regulation of GUSP expression. This is an important study as no report of this universal stress protein promoter is available in literature. 相似文献
894.
Luc Mevaa Mbaze Jean Alexandre Lado Jean Duplex Wansi Tze Chieh Shiao David Dako Chiozem Muhammad Ahmed Mesaik Muhammad Iqbal Choudhary Marie-Aleth Lacaille-Dubois Jean Wandji Ren Roy Norbert Sewald 《Phytochemistry》2009,70(11-12):1442-1447
Two amides, heitziamide A and heitziamide B and two phenylethanoids, heitziethanoid A and heitziethanoid B together with thirteen known compounds were isolated from F. heitzii (Letouzey). The structures of all compounds were established by spectroscopic analysis.Nine compounds were evaluated for oxidative burst inhibitory activity in a chemoluminescence assay and for cytotoxicity against PC-3 prostate cancer cells.All compounds exhibited a clear suppressive effect on phagocytosis response upon activation with serum opsonized zymosan at the range of IC50 = 2.0–6.5 μM, but no cytotoxic effect was observed (IC50 > 100 μM). 相似文献
895.
Ectodermal dysplasia syndromes are genetically heterogeneous group of disorders involving one or more of the classical ectodermal
appendages (hair, nail, teeth, sweat glands) in association with anomalies of other organs or systems. In the present study
a novel form of ectodermal dysplasia syndrome, ectodermal dysplasia cutaneous syndactyly (EDCS), segregating in an autosomal
recessive pattern in a Pakistani family was investigated. The clinical features of the affected individuals included large
prominent ear pinnae, tooth enamel hypoplasia, hypoplastic nails, bilateral partial cutaneous syndactyly, hypotrichosis, palmoplantar
keratoderma and hyperhidrosis. Through genetic linkage study, EDCS syndrome was mapped on human chromosome 7p21.1-p14.3 flanked
by markers D7S488 and D7S817. A maximum two-point LOD score of 2.94 (θ = 0.00) was obtained at marker D7S2496 while a maximum
multipoint LOD score of 3.07 was obtained with several markers along the disease-interval. This interval spans 19.80-cM, which
corresponds to 13.74-Mbp according to the sequence-based physical map (Build 36.1). Sequence analysis of 27 candidate genes,
located in the candidate interval, did not reveal any functional sequence variant. 相似文献
896.
Mahjabeen Saleem Muhammad Rizwan Tabassum Riffat Yasmin Muhammad Imran 《International biodeterioration & biodegradation》2009,63(8):1119-1124
An extracellular xylanase produced under optimal conditions by a thermophilic strain of Bacillus sp. XTR-10 was evaluated for its potential application in biobleaching of wood kraft pulp. Spectrophotometric analysis showed considerable release of lignin derived compounds and chromophoric material by the xylanase treated pulp samples. Xylanase was found to be effective in the liberation of reducing sugars in the pulp filtrates with increment in enzyme dose and reaction time. Eight hours pretreatment with 40 IU of xylanase/g of dry pulp resulted in 16.2% reduction of kappa number with 25.94% ISO increase in brightness as compared to the control. The same treatment slightly lowered the tensile strength and burst index, however. Enzyme pretreatment of the pulp saved 15% active chlorine charges in single step and 18.7% in multiple steps chemical bleaching with attainment of brightness at the level of the control. These results indicate the potential of enzymatic pretreatment of pulp for reduction in environmental discharge of hazardous waste from the pulp and paper industry. 相似文献
897.
898.
A rapid, simple in vitro test system for high-throughput screening of peroxisome proliferator-activated receptor (PPAR) γ agonists would be of interest for testing new antidiabetic drugs, alternative medicine, or environmental samples. A yeast two-hybrid assay based on the ligand-dependent recruitment of the coactivator CBP (CREB-binding protein) was constructed. In this system PPARγ was constitutively activated and the signal was not further increased significantly by adding agonists. In yeast we identified oleic acid as a putative endogenous ligand. Furthermore yeasts seem to lack regulatory mechanisms present in mammalian cells. Mammalian systems are an alternative for screening PPARγ agonists. 相似文献
899.
An amperometric lactate biosensor was developed based on a conducting polymer, poly-5,2′-5′,2′′-terthiophene-3′-carboxylic acid (pTTCA), and multiwall carbon nanotube (MWNT) composite on a gold electrode. Lactate dehydrogenase (LDH) and the oxidized form of nicotinamide adenine dinucleotide (NAD+) were subsequently immobilized onto the pTTCA/MWNT composite film. The modified electrode was characterized by quartz crystal microbalance (QCM), scanning electron microscopy (SEM), and electrochemical experiments. The detection signal was amplified by the pTTCA/MWNT assembly onto which a sufficient amount of enzyme was immobilized and stabilized by the covalent bond formation between the amine groups of enzyme and the carboxylic acid groups of the pTTCA/MWNT film. Experimental parameters affecting the sensor responses, such as applied potential, pH, and temperature, were assessed and optimized. Analytical performances and dynamic ranges of the sensor were determined, and the results showed that the sensitivity, stability, and reproducibility of the sensor improved significantly using pTTCA/MWNT composite film. The calibration plot was linear (r2 = 0.9995) over the range of 5 to 90 μM. The sensitivity was approximately 0.0106 μA/μM, with a detection limit of 1 μM, based on a signal/noise ratio of 3. The applicability of the sensor for the analysis of l-lactate concentration in commercial milk and human serum samples was demonstrated successfully. 相似文献
900.
Kang SM Joo GJ Hamayun M Na CI Shin DH Kim HY Hong JK Lee IJ 《Biotechnology letters》2009,31(2):277-281
Plant growth-promoting rhizobacteria with gibberellins (GA)-producing potential were isolated from soil and screened for plant
growth promotion. A new strain, Acinetobacter calcoaceticus SE370, produced extracellular GA and also had phosphate solubilising potential. It produced 10 different gibberellins, including
the bioactive GA1, GA3 and GA4 which were at, respectively, 0.45, 6.2 and 2.8 ng/100 ml. The isolate solubilised tricalcium phosphate and lowered pH of
the medium during the process. Culture filtrates of the organism after growth on broth promoted growth of cucumber, Chinese
cabbage and crown daisy.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献