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71.
El-Menshawi BS Fayad W Mahmoud K El-Hallouty SM El-Manawaty M Olofsson MH Linder S 《Indian journal of experimental biology》2010,48(3):258-264
Most of the currently used cancer therapeutics are natural products. These agents were generally discovered based on their toxicity to tumour cells using various bioassays. Although the exact mechanisms of action of the most commonly used cancer therapeutics such as anthracyclins, podophyllotoxins and camptothecin are incompletely understood, it is becoming increasingly clear that these agents often show complex modes of action at the cellular level, interacting with numerous targets. Such complex modes of action may be the very reason for clinical efficacy. For discovering new cytotoxic anticancer drugs sophisticated screening methods were used. The principles of such screening projects conducted, using collections of purified natural products or extracts from plants have been described. By performing simple but robust prescreening tests such as the brine shrimp assay, bioactive extracts can be identified. Extracts (65) prepared from a collection of Egyptian plants were identified that showed cytotoxity on HepG2 cells. Interestingly, 22 (33%) of these raw extracts, induced > 2-fold induction of caspase-cleavage activity in a colon carcinoma cell line, consistent with induction of apoptosis. Only a fraction of the diversity of the biosphere has been tested for biological activity and novel cancer therapeutics remains to be discovered. 相似文献
72.
Purification and characterization of pullulanase from Aureobasidium pullulans. Pullulanase was purified by using gel—filtration column then on ion exchange using Q-sepharose column yielding a single
peak. Purification was further carried out on SP-sepharose column. Molecular weight of pullulanase from A. pullulans was found to be about 73 KDa on the SDS-PAGE 10%. Native-PAGE 10% showed the activity of pullulanase, using polyacrylamide
gel containing pullulan. Hydrolysis products from pullulanase activity with soluble starch, glycogen and pullulan on thin
layer chromatography appeared as one band which is maltotriose, while α-amylase with soluble starch and glycogen showed two
bands which are maltose and maltotriose but α-amylase gave negative result with pullulan on TLC chromatography only. Pullulanase
could degrade α-1,6 glycosidic linkage of the previous substrates, while amylase could degrade α-1,4 glycosidic linkage of
glycogen, soluble starch and pullulan. MALDI-Ms was employed to deduce protein sequence of pullulanase. 相似文献
73.
Meat samples from sheep, bovine, camel and poultry were collected from Amman area and were processed and tested for the presence of methicillin (oxacillin) resistantStaphylococcus aureus (MRSA). Identity ofS. aureus was ensured by Gram-staining and a battery of biochemical tests. From 1260 meat samples, 157S. aureus positive isolates were identified. Of the 157 isolates, 30 were resistant to methicillin levels greater than 2 μg/ml and only 15 weremecA-positive MRSA originating mainly from sheep and chicken. Subjecting themecA-positive MRSA to antibiotic susceptibility testing revealed that all isolates were resistant to β-lactam antibiotics (ampicillin, penicillin, and oxacillin) and were sensitive to vancomycin, trimethoprim, chloramphenicol and cephalothin. Randomamplified polymorphic DNA (RAPD) analysis ofmecA-positive animal isolates generated six different patterns. Comparing these results with results of isolates of human origin of our laboratory there is some molecular epidemiological relatedness between both and could be a possible source of infections through consuming contaminated meat products, direct contact or meat processing. 相似文献
74.
Simon Rajendran Slawomir Salwa Xuefeng Gao Sabin Tabirca Deirdre O'Hanlon Gerald C. O'Sullivan Mark Tangney 《Journal of visualized experiments : JoVE》2010,(46)
This video describes the use of patient tissue as an ex vivo model for the study of gene delivery. Fresh patient tissue obtained at the time of surgery is sliced and maintained in culture. The ex vivo model system allows for the physical delivery of genes into intact patient tissue and gene expression is analysed by bioluminescence imaging using the IVIS detection system. The bioluminescent detection system demonstrates rapid and accurate quantification of gene expression within individual slices without the need for tissue sacrifice. This slice tissue culture system may be used in a variety of tissue types including normal and malignant tissue and allows us to study the effects of the heterogeneous nature of intact tissue and the high degree of variability between individual patients. This model system could be used in certain situations as an alternative to animal models and as a complementary preclinical mode prior to entering clinical trial.Download video file.(23M, mov) 相似文献
75.
Khaled K. Aldossari Mamdouh M. Shubair Sameer Al-Ghamdi Jamaan Al-Zahrani Mansour AlAjmi Saeed Mastour Alshahrani Majid Alsalamah Badr F. Al-Khateeb Salwa Bahkali Ashraf El-Metwally 《Saudi Journal of Biological Sciences》2021,28(5):2783-2788
ObjectivesThe objective of this study was to compare the association between mental well-being between obese (classes 1 and 2), over-weight and non-obese population-based individualsMethodsA population-based cross-sectional study was conducted in Al-Kharj, Saudi Arabia. A total of 1019 Saudi nationals aged ≥ 18 years participated in the survey. BMI scores were used to categorize participants into three groups: Obese, overweighted and non-obese/non-overweight. Mental well-being was evaluated by using the validated Arabic version of the General Health Questionnaire version 12 (GHQ-12).ResultsWe used total GHQ score (Mean=12; SD=5.23) to compare mental well-being between the four BMI class categories. The overall one-way ANOVA model was statistically significant (F = 7.018, d = 6, P < 0.001). In multivariate analysis, after adjusting for sociodemographic variables, diabetes and smoking statuses we found that higher psychological distress (as evident by a higher total GHQ score) was associated with higher BMI. The unstandardized Beta regression coefficient = 2.627; P = 0.034). Females were more likely to have higher psychological distress than males (unstandardized Beta = 1.466, P = 0.003). Job status whether being unemployed or ‘civilian’ (civil worker) was significantly associated with higher psychological distress (unstandardized Beta = 1.405, P = 0.041). Being diabetic has a 1.6 times higher risk of psychological distress (unstandardized Beta = 1.604, P = 0.027).ConclusionThe study highlights the public health implications of psychological distress amongst individuals with overweight and obesity in Saudi Arabia. Future longitudinal studies should explore the temporality of this relationship. 相似文献
76.
Kebba Sabally Salwa Karboune Faustinus K. Yebaoh 《Biocatalysis and Biotransformation》2013,31(1):37-44
The enzymatic esterification of dihydrocaffeic acid with linoleyl alcohol, using immobilized lipases (Lipozyme IM 20 and Novozym 435), was investigated in selected organic solvent media. Novozym 435 was found to be more efficient for catalyzing the esterification reaction. The highest enzymatic activity of 0.89 μmol esterified linoleyl alcohol/g solid enzyme/min was obtained in a hexane/2-butanone mixture of 75:25 (v/v), with an esterification yield of 75%; however, an increase in the 2-butanone proportion in the mixture up to 50% (v/v) resulted in a decrease in enzymatic activity and esterification yield to 0.38 μmol esterified linoleyl alcohol/g solid enzyme/min and 40%, respectively. The maximum esterification yield of 99.3% was obtained with a dihydrocaffeic acid to linoleyl alcohol ratio of 1:8. The electrospray ionization-mass spectroscopic structural analysis of the end products confirmed the biosynthesis of dihydrocaffeic acid ester of linoleyl alcohol, which demonstrated an anti-radical activity using 2,2-diphenyl-1-picrylhydrazyl as a radical model. 相似文献
77.
Amany El-Wakkad Nayera El-Morsi Hassan Hiba Sibaii Salwa Refat El-Zayat 《Cytokine》2013,61(2):682-687
Several studies have investigated the correlation between central obesity and inflammatory cytokines and the anti-inflammatory cytokine adiponectin. But, the correlation between central obesity and the anti-inflammatory cytokines IL-4, IL-5 has not been studied yet. Thus, we aimed to study the IL-4 and IL-5 correlation to central obesity in adolescent Egyptian girls among proinflammatory and anti-inflammatory cytokines. The study was carried out on 86 obese adolescent girls (BMI > 95 percentile) divided into two groups according to central obesity. The group I with waist to hip ratio <0.8 as a control and group II with waist to hip ratio >0.8 (central obesity). There was a significant increase in TNF-alpha (p < 0.0001), and IL-1β (p < 0.0001), as proinflammatory cytokines in group II, as compared to their corresponding group I. Group II showed a significant increase in the anti-inflammatory cytokines IL-4 and IL-5 than group I at (p < 0.0001) and (p < 0.0005) respectively. In addition there was a significant decrease in the anti-inflammatory adiponectin and an increase in the inflammatory leptin levels in group II at (p < 0.0001) and (p < 0.0001) respectively in comparison to group I. A high positive correlation has been observed between waist to hip ratio, leptin, TNF-α, IL-1-β, IL-4 and IL-5 at (r = 0.331, p < 0.03), (r = 0.559, p < 0.001), (r = 0.435, p < 0.004), (r = 0.509, p < 0.001), (r = 0.550, p < 0.0015), in group II respectively and a high negative one with adiponectin at (r = ?0.410, p < 0.0001). We concluded that central obesity lowers adiponectin plasma level through increasing proinflammatory adipokines such as TNF-α, IL-1β, leptin. Further studies are needed to explore the positive correlation we found between central obesity and the anti-inflammatory cytokines IL-4 and IL-5 known to be associated with bronchial asthma. 相似文献
78.
The intra- and extracellular levansucrase (LS) activities produced by Bacillus amyloliquefaciens were promoted by supplementing the sucrose medium with yeast and peptone as nitrogen sources. These activities were purified by polyethylene glycol (PEG) fractionation for the first time. PEGs of low molecular weight selectively fractionated the intracellular LS activity rather than the extracellular LS activity. Contrary to other LSs, B. amyloliquefaciens LSs exhibited high levan-forming activity over a wide range of sucrose concentrations. The optimum temperatures for the intra- (25-30 °C) and extracellular (40 °C) LS transfructosylation activities were lower than those for the hydrolytic activities (45-50 °C; 50 °C). In addition, the catalytic efficiency for the transfructosylation activity of intracellular LS was higher than that of extracellular LS. These differences between intra- and extracellular LSs reveal the occurrence of certain conformational changes to LS upon protein secretion and/or purification. This study is the first to highlight that B. amyloliquefaciens LSs synthesized a variety of FOSs from various saccharides, with lactose and maltose being the best fructosyl acceptors. 相似文献
79.
Yannick R. Brunet Leon Espinosa Seddik Harchouni Tâm Mignot Eric Cascales 《Cell reports》2013,3(1):36-41
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80.
Noha Sorour Salwa Karboune Richard Saint-Louis Selim Kermasha 《Process Biochemistry》2012,47(12):1813-1819
The enzymatic synthesis of phenolic lipids (PLs) by transesterification of flaxseed oil with 3,4-dihydroxyphenyl acetic acid (DHPA) was investigated in solvent-free medium (SFM), using Novozym 435 from Candida antarctica as the biocatalyst. The effects of selected reaction parameters, water activity (aw), enzyme concentration and agitation speed, were studied and optimized. Increasing the aw of the reaction mixture from 0.18 to 0.38 resulted in a significant increase in the bioconversion yield from 62 to 77%. APCI–MS analysis confirmed the formation of six 3,4-dihydroxyphenyl acetoylated lipids, which were monolinolenyl, dioleyl, dilinolenyl, linoleyl linolenyl, oleyl linolenyl and oleyl linoleyl dihydroxyphenyl acetates. The highest enzymatic activity (178 nmol of PLs/g solid enzyme/min) was obtained using 40 mg of solid enzyme (400 PLU)/mL at agitation speed 150 rpm. Using the optimized conditions, the phenolic lipids showed a high relative proportion of linolenic acid (C18:3 n?3) that increased from 57% in the flaxseed oil to 75 and 64% in the produced phenolic mono- and diacylglycerols, respectively. In addition, the synthesized phenolic lipids demonstrated a 7.2-fold lower radical scavenging activity than that of DHPA but half that of α-tocopherol. 相似文献