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排序方式: 共有470条查询结果,搜索用时 23 毫秒
111.
Desmond Slade Ahmed M. Galal Waseem Gul Mohamed M. Radwan Safwat A. Ahmed Shabana I. Khan Babu L. Tekwani Melissa R. Jacob Samir A. Ross Mahmoud A. ElSohly 《Bioorganic & medicinal chemistry》2009,17(23):7949-7957
Nine dihydroartemisinin acetal dimers (6–14) with diversely functionalized linker units were synthesized and tested for in vitro antiprotozoal, anticancer and antimicrobial activity. Compounds 6, 7 and 11 [IC50: 3.0–6.7 nM (D6) and 4.2–5.9 nM (W2)] were appreciably more active than artemisinin (1) [IC50: 32.9 nM (D6) and 42.5 nM (W2)] against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of the malaria parasite, Plasmodium falciparum. Compounds 10, 13 and 14 displayed enhanced anticancer activity in a number of cell lines compared to the control drug, doxorubicin. The antifungal activity of 7 and 12 against Cryptococcus neoformans (IC50: 0.16 and 0.55 μM, respectively) was also higher compared to the control drug, amphotericin B. The antileishmanial and antibacterial activities were marginal. A number of dihydroartemisinin acetal monomers (15–17) and a trimer (18) were isolated as byproducts from the dimer synthesis and were also tested for biological activity. 相似文献
112.
Optimization of media components for the growth and biomass production of Halobacterium salinarum VKMM 013 was carried out using response surface methodology. A second order quadratic model was estimated and media components were determined based on quadratic regression equation generated by model. These were 6.35 g L−1 of KCl, 9.70 g L−1 of MgSO4, 13.38 g L−1 of gelatin and 12.00 g L−1 of soluble starch in nutrient broth supplemented with artificial seawater with 20% (w/v) of NaCl. In these optimal conditions, the obtained cell concentration of 0.746 g L−1 dry weight was in agreement with the predicted cell concentration. The optimized media significantly shortened the time required for cell culture to reach the stationary phase while providing a nearly 2.4-fold increase in biomass production. Furthermore, in cell cultures of three other halophilic archaea the use of optimized media enhanced growth rate and provided high-cell density. 相似文献
113.
Turgay Kacar Melvin T. Zin Christopher So Brandon Wilson Hong Ma Nevin Gul‐Karaguler Alex K.‐Y. Jen Mehmet Sarikaya Candan Tamerler 《Biotechnology and bioengineering》2009,103(4):696-705
Current biotechnological applications such as biosensors, protein arrays, and microchips require oriented immobilization of enzymes. The characteristics of recognition, self‐assembly and ease of genetic manipulation make inorganic binding peptides an ideal molecular tool for site‐specific enzyme immobilization. Herein, we demonstrate the utilization of gold binding peptide (GBP1) as a molecular linker genetically fused to alkaline phosphatase (AP) and immobilized on gold substrate. Multiple tandem repeats (n = 5, 6, 7, 9) of gold binding peptide were fused to N‐terminus of AP (nGBP1‐AP) and the enzymes were expressed in E. coli cells. The binding and enzymatic activities of the bi‐functional fusion constructs were analyzed using quartz crystal microbalance spectroscopy and biochemical assays. Among the multiple‐repeat constructs, 5GBP1‐AP displayed the best bi‐functional activity and, therefore, was chosen for self‐immobilization studies. Adsorption and assembly properties of the fusion enzyme, 5GBP1‐AP, were studied via surface plasmon resonance spectroscopy and atomic force microscopy. We demonstrated self‐immobilization of the bi‐functional enzyme on micro‐patterned substrates where genetically linked 5GBP1‐AP displayed higher enzymatic activity per area compared to that of AP. Our results demonstrate the promising use of inorganic binding peptides as site‐specific molecular linkers for oriented enzyme immobilization with retained activity. Directed assembly of proteins on solids using genetically fused specific inorganic‐binding peptides has a potential utility in a wide range of biosensing and bioconversion processes. Biotechnol. Bioeng. 2009;103: 696–705. © 2009 Wiley Periodicals, Inc. 相似文献
114.
Substituted polyaniline/chitosan(PANIs/Ch) composites were chemically synthesized by using ammonium peroxydisulfate as oxidant and characterized by measurements of conductivity, FTIR, UV–vis, SEM and TGA techniques. FTIR spectra of the composites revealed that there is a strong interaction between substituted polyanilines and chitosan. Among the substituted polyaniline/chitosan composites synthesized, poly(N-ethylaniline)/chitosan PNEANI/Ch has the highest conductivity with a value of 1.68 × 10?4 S/cm. The P2EANI/Ch composite exhibited higher thermal stability than the other composites. SEM images of the composites showed an agglomerated granular morphology of substituted polyaniline particles coated on the surface of chitosan. 相似文献
115.
Kazi TG Jalbani N Kazi N Arain MB Jamali MK Afridi HI Kandhro GA Sarfraz RA Shah AQ Ansari R 《Biological trace element research》2009,127(1):16-27
The determination of toxic metals (TMs) in the biological samples of human beings is an important clinical screening procedure.
The aim of this work is to determine total content of TMs, aluminum (Al), cadmium (Cd), nickel (Ni), and lead (Pb) in scalp
hair samples of chronic kidney male patients (CKPs) on maintenance hemodialysis, during the period of 2005–2007. The study
included 115 CKPs (all smokers) and 150 controls or referents [82 (nonsmokers) and 68 (smokers)]. Both controls and patients
(males) were of the same age group (ranged 25–55 years), socioeconomic status, localities, and dietary habits. The scalp hair
samples were analyzed by electrothermal atomic absorption spectrometer, prior to microwave-induced acid digestion. The accuracy
of the total Al, Cd, Ni, and Pb measurements was tested by simultaneously analyzing certified reference material (human hair
NCS ZC81002). No significant differences were observed between the analytical results and the certified values (paired t test at p > 0.05). The levels of TMs in scalp hair samples of patients were found to be higher as compared to control nonsmoker and
smokers. Moreover, the study shows that levels of Al, Cd, Ni, and Pb in scalp hair samples may be useful to evaluate the impact
of cigarette smoking in kidney failure patients. 相似文献
116.
B. Karabulut M.K. Gul B. Karaca G. Gorumlu S. Uzunoglu Y. Baran 《Cell biology international》2009,33(2):239-246
Docetaxel, a semi-synthetic taxane analogue, is used effectively in the treatment of metastatic prostate cancer. Zoledronic acid, the most potent member of bisphosphonates, has shown pleiotropic anti-tumoral effects on prostate cancer cells. We have explored the possible additive/synergistic effects and the apoptotic pathways induced by combination treatment of docetaxel and zoledronic acid in hormone and drug refractory, PC-3 and DU-145 prostate cancer cells. Combination of docetaxel and zoledronic acid synergistically inhibits cell growth in PC-3 and DU-145 cells. Moreover, this effect was due to downregulation of antiapoptotic protein Bcl-2 in PC-3 and DU-145 cells. In conclusion, docetaxel/zoledronic acid combination is potentially a novel and effective approach for the treatment of prostate cancer. 相似文献
117.
Gul W Hammond NL Yousaf M Bowling JJ Schinazi RF Wirtz SS de Castro Andrews G Cuevas C Hamann MT 《Bioorganic & medicinal chemistry》2006,14(24):8495-8505
As part of an investigation to generate optimized drug leads from marine natural pharmacophores for the treatment of neoplastic and infectious diseases, a series of novel isoaaptamine analogs were prepared by coupling acyl halides to the C9 position of isoaaptamine (2) isolated from the Aaptos sponge. This library of new semisynthetic products was evaluated for biological activity against HIV-1, Mtb, AIDS-OI, tropical parasitic diseases, and cancer. Compound 4 showed potent activity against HIV-1 (EC50 0.47 μg/mL), compound 19 proved to possess remarkable activity against Mycobacterium intracellulare with an IC50 and MIC value of 0.15 and 0.31 μg/mL, while compounds 4 and 17 possessed anti-leishmanial activity with IC50 values of 0.1 and 0.4 μg/mL, respectively. Compounds 16 and 17 showed antimalarial activity with EC50 values of 230 and 240 ng/mL, respectively, and compound 14 exhibited an EC50 of 0.05 μM against the Leukemia cell line K-562. 相似文献
118.
Gulay Ciftci Sena Cenesiz Gul Fatma Yarim Ozlem Nisbet Cevat Nisbet Metin Cenesiz Dilek Guvenc 《Biological trace element research》2010,133(1):51-59
This study describes the effects of fluoride exposure on the protein profile, glycoprotein pattern, and total sialic acid
concentration of serum in rabbits. For this aim; 20 healthy New Zealand rabbits were used. The rabbits were divided into two
equal groups each with ten animals according to their weighing: control group and experimental group. The rabbits in control
group were given drinking tap water containing 0.29 mg/l sodium fluoride and experimental group received the same tap water
to which was added 40 mg/l sodium fluoride for 70 days. Blood samples were taken from each rabbit on day 70. Serum fluoride
concentrations were measured by a fluoride-specific ion electrode in serum. The fluoride levels in the serum were found as
18.4 (±1.58) μg/L in control and 301.3 (±52.18) μg/L in fluoride exposed rabbits. The sialic acid levels were found as 69.2
(±0.32) mg/dL in control and 43.4 (±0.13) mg/dL in fluoride exposed group. The electrophoretic patterns of serum proteins,
glycoproteins, and total sialic acid concentration were determined. Fifteen different protein fractions with molecular weights
ranging from 22 to 249 kDa were displayed in the serum protein electrophoretic gel of both groups. The raw concentrations
of the protein fractions decreased in fluoride exposed rabbits as compared with the control rabbits. The serum glycoprotein
pattern revealed seven major protein bands from 47 to 167 kDa in experimental and control groups. The slight decrease of raw
concentration of the protein bands in glycoprotein pattern of serum was observed in fluoride toxication comparing to control.
The results suggest that serum TSA determination and serum protein electrophoresis can be used to evaluate prognosis of fluoride
exposure as a supplementary laboratory test in combination with clinical and other laboratory findings of fluorosis. 相似文献
119.
Tasneem Gul Kazi Ghulam Abbas Kandhro Hassan Imran Afridi Naveed Kazi Jameel Ahmed Baig Mohammad Balal Arain Abdul Qadir Shah Nasreen Syed Sham Kumar Nida Fatima Kolachi Sumaira Khan 《Biological trace element research》2010,134(3):265-279
In many developing countries, men and women are at high risk of goiter and iron deficiency. The aim of the recent study is to assess the interaction of (Cu), with iron (Fe), iodine/iodide (I), and thyroid hormones in goitrous patients. Sixty goitrous male (GMPs) and 72 female patients (GFPs) were evaluated for the Cu, Fe, I, and thyroid hormones status in biological samples (serum and urine), and compared to non-goitrous subjects of both genders (M?=?106, F?=?120). The biological samples were analyzed for Cu and Fe concentration using atomic absorption spectrometer, while I was measured by the potentiometric method, prior to microwave-assisted acid digestion (MD). Quality control for the method was established with certified samples. Significantly higher mean values of Cu in serum, and urine samples of GMPs and GFPs, while lower value of Fe and I were observed as compared to control subjects (p?<?0.015), respectively. The mean values of free triiodothyronine (FT3) and free thyroxin (FT4) were found to be lower in goitrous patients of both genders than in the age-matched healthy controls (p?<?0.006 and 0.002), respectively, in contrast high mean values of thyroid-stimulating hormone (TSH) were detected in patients (p?<?0.009), as compared to non-goitrous subjects. It was observed that the deficiencies of Fe, I, and thyroid hormone in goitrous patients could be influenced by efficiency of Cu. 相似文献
120.
Oxana B. Kazakova Gul’nara V. Giniyatullina Emil Yu. Yamansarov Genrikh A. Tolstikov 《Bioorganic & medicinal chemistry letters》2010,20(14):4088-4090
The synthesis of new betulin and ursolic acid derivatives and evaluation of their antiviral activity in vitro is reported. Betulin was modified at positions C-3, C-20 and C-28 to afford the derivatives with nicotinoyl-, methoxycynnamoyl-, alkyne and aminopropoxy-2-cyanoethyl-moieties. The two stage conversion of betulin to the new ursane-type triterpenoid by treatment of allobetulin with Ac2O–HClO4 is suggested. Cyanoethylation of ursonic acid oxime led to cyanoethyloximinoderivative. According to the results of antiviral screening against human papillomavirus type 11 the selectivity index for tested triterpenoids has a range from 10 to 35 with no cellular cytotoxicite, the most remarkable activity was found for 3β,28-di-O-nicotinoylbetulin. 3β,28-Dihydroxy-29-norlup-20(30)-yne was also active against HCV replicon (EC50 1.32; EC90 16.82; IC50 12.41; IC90 >20; SI50 9.4; SI90 >1.19). 28-O-Methoxycynnamoylbetulin was active against influenza type A virus (H1N1) (ЕС50 2; IC50 >200; SI >100). 相似文献