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151.
Karray-Chouayekh S Trifa F Khabir A Sellami-Boudawara T Frikha M Gargouri A Mokdad-Gargouri R 《Histology and histopathology》2012,27(3):377-385
The loss of E-cadherin expression leads to absence of tissue integrity, an essential step in tumor progression. Methylation of CpG islands in the promoter region of the CDH1 gene coding E-cadherin might be an alternative for gene silencing. In the present study, we investigate the expression of E-cadherin and hormone receptors in invasive ductal breast carcinoma (IDCs). Protein expression was analysed immunohistochemically in 87 cases, including 26 familial tumors. The most interesting results revealed a significantly reduced E-cadherin expression in cases with familial history compared to sporadic tumors (p=0.009), as well as with tumors ≤5 cm (p=0.022). Moreover, HER2 over-expression was associated with distant metastasis (p=0.011) and overall survival (p log rank=0.028). Tumors displaying negative/low HER2 expression combined with E-cadherin positivity confer better patient survival (p=0.052). Triple Negative tumors (TN) were more frequently found in patients with advanced grade (GIII) (p=0.001) and TNM (III+IV) (p=0.018) which supports the aggressive behavior of TN tumors. On the other hand, hypermethylation of CDH1 gene promoter was observed in 46% of hereditary cases and strongly associated with loss of E-cadherin expression (p=0.002). Furthermore, patients with unmethylated CDH1 pattern have a better 5-year disease free survival (p=0.021). In conclusion, in patients with hereditary breast cancer, the CpG methylation event contributes to the loss of E-cadherin expression. On the other hand, HER2 over-expression is predictive of worse prognosis, either alone or combined with loss of E-cadherin expression in Tunisian patients with breast cancer. 相似文献
152.
Imen Aissa Mohamed Bouaziz Fakher Frikha Riadh Ben Mansour Youssef Gargouri 《Process Biochemistry》2012,47(12):2356-2364
New tyrosyl ester derivative, a naturally occurring phenol with interesting biological properties, has been synthesized in good yield by a direct esterification of tyrosol (Ty) with p-hydroxyphenylacetic acid (p-HPA) using Candida antarctica lipase as a catalyst. The response surface methodology was used to modulate the effects of the enzyme amount (10–50 mg), the tert-butanol/hexane (v/v) ratio (0.16–0.84), the temperature (35–55 °C) and the reaction time (15–45 h) on the tyrosyl hydroxyphenylacetate (Ty-HPA) conversion yield. Under the optimal predicted conditions (enzyme amount: 10 mg, solvents volume ratio 0.16, reaction temperature; 45 °C and 34 h of incubation), a high conversion yield of 79.33 ± 4% was reached. The obtained ester was purified and characterized by NMR, LC/MS and FT-IR methods. ABTS free radical quenching potency demonstrated that the esterified tyrosol (Ty-HPA) was more effective than the natural separated antioxidants: Ty and p-HPA. Furthermore, when used at a non-cytotoxic concentration (100 μM), tyrosyl ester showed significant effectiveness in preventing iron-induced oxidative stress in blood cells compared to the two separated compounds. The antibacterial activity of Ty, p-HPA, mixed solution of Ty + p-HPA and Ty-HPA was performed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a micro-well dilution method. Compared to the separated substrates, synthesized ester exhibits the most antibacterial effect mainly against Gram+ bacteria. 相似文献
153.
An extracellular high molecular weight β-glucosidase was secreted by a local strain P1 of Beauveria bassiana. The enzyme was produced in the presence of various carbon sources, namely glucose, maltose, lactose, glycerol, starch, wheat bran and gruel. The highest level of β-glucosidase activity was produced with wheat bran at the concentration of 3%. Glucose caused a repressor effect on the β-glucosidase expression in a dose-dependent manner. The highest enzyme production level was obtained at initial pH of 6.0 and 7.0 in the culture medium. The zymography analysis revealed that B. bassiana secreted a β-glucosidase with high molecular weight between 400 and 600 kDa. The enzymatic preparation was characterized and showed temperature and pH optima of 55°C and 5.0, respectively. The enzyme was stable at 40 and 50°C but its stability declined at 60°C. Interestingly, this β-glucosidase had high stability at acid and basic pH saving its initial activity after 24 h incubation at pH from 3.0 to 11.0. It was stable also in presence of monovalent Na+ and K+ ions saving 60% of its initial activity at 2 M salts. Bivalent metal ions preserved totally or partially the enzymatic activity; in addition, Ba2+ was revealed as an activator. This is the first report that focuses on the production and the biochemical characterization of a β-glucosidase from the entomopathogenic fungus, B. bassiana. 相似文献
154.
Ines Ayadi Omama Kamoun Hèla Trigui-Lahiani Anouar Hdiji Ali Gargouri Hafedh Belghith Mohamed Guerfali 《Journal of industrial microbiology & biotechnology》2016,43(7):901-914
Microbial lipids have drawn increasing attention in recent years as promising raw materials for biodiesel and added-value compounds production. To this end, new oleaginous yeast, Candida viswanathii Y-E4 was isolated, characterized and used for single cell oil (SCO) production. Physiologic and nutritional parameters optimization was carried out for improved biomass and lipid production. Y-E4 strain was able to use a wide range of substrates, especially C5 and C6 sugars as well as glycerol and hydrophobic substrates. The fatty acid profile analysis showed that oleic acid was the main component produced using different substrates. Batch and fed-bath fermentation were conducted using glucose as carbon source. Lipid production rate is twice higher in fed-batch culture providing a lipid content of 50 % (w/w). To minimize the SCO production cost, C. viswanathii Y-E4 was evaluated for its capacity to use different agro-industrial by-products for microbial oil production and changes in the fatty acid profile were monitored. 相似文献
155.
Riadh Ben Mansour Imtinen Ben Haj Jilani Mohammed Bouaziz Bochra Gargouri Nésrine Elloumi Hamadi Attia Zeineb Ghrabi-Gammar Saloua Lassoued 《Cytotechnology》2016,68(1):135-142
Caper plant (Capparis spinosa) extracts have been associated with diverse biological activities including anti-oxidant properties. In this work, we characterized the hydro-ethanolic extract obtained from C. spinosa leaves [hydroethanolic extract of C. spinosa (HECS)] by analyzing the content in anti-oxidant compounds such as polyphenols, flavonoids and anthocyanins. Further, we evaluated HECS antioxidant activities in vitro using bleaching of 1,1-diphenyl-2-picrylhydrazyl radical and ABTS test as well as by pretreatment of HeLa cells exposed to Fe2+ or H2O2. Our findings indicate that HECS contains high amount of total phenolic compounds and high levels of flavonoids and anthocyanins. Furthermore, HECS exhibited antioxidant activity in both chemical and biological tests. Specially, pretreatment of HeLa cells with different concentrations of the extract conferred protection against lipid peroxidation and modulated activities of two antioxidant enzymes, SOD and catalase. These results revealed HECS antioxidant effects and suggest that C. spinosa leaves are a potential source of natural antioxidant molecules with possible applications in industry and medicine. 相似文献
156.
Riadh Ben Salah Ali Gargouri Robert Verger Youssef Gargouri Hafedh Mejdoub 《World journal of microbiology & biotechnology》2009,25(8):1375-1384
The sequence corresponding to the mature lipase of Rhizopus oryzae WPG (ROLw) was subcloned in the pPIC9K expression vector, with a strong AOX1 promoter, to construct a recombinant lipase protein containing six histidine residues at the N-terminal. The His-tagged lipase
was expressed in Pichia Pastoris X33 and purified to homogeneity by a simple, one-step purification protocol using immobilized metal affinity chromatography (Ni-NTA
resin). High level expression of the lipase by Pichia Pastoris X33 cells harbouring the lipase gene containing expression vector was observed upon induction with 2.5 g/l methanol at 28°C;
the specific activity of the purified His6-ROLw was 1,500 or 760 U/mg using olive oil emulsion or tributyrin as substrates, respectively. To check the importance of
Asn 134 His substitution in the affinity and substrate selectivity of ROLw, the mutant His6-ROLw-N134H was overexpressed in Pichia Pastoris X33 and purified with the same nickel metal affinity column. The specific activity of the purified His-tagged ROLw-N134H
was 5,900 and 35 U/mg using olive oil emulsion or tributyrin as substrate. A comparative study of the wild type (His6-ROLw) and the mutant (His6-ROLw-N134H) proteins was carried out. A 3D structure model of ROLw was built using the RNL structure as template. We have
concluded that a slight increase in the exposed hydrophilic residues on the surface of ROLw as compared to RNL (ROLwN134H)
could be responsible for a higher selectivity of ROlw for long and short chain triacylglycerols at the lipid/water interface
and then explaining the importance of Asn 134 for the chain length specificity of ROLw. This property is quite rare among
Rhizopus lipases and gives this new lipase great potential for use in the field of biocatalysis. 相似文献
157.
Habib Horchani Habib Mosbah Nadia Ben Salem Youssef Gargouri Adel Sayari 《Journal of Molecular Catalysis .B, Enzymatic》2009,56(4):237-245
A newly soil-isolated Staphylococcus aureus strain secretes a non-induced lipase in the culture medium. The extracellular lipase from S. aureus (SAL3) is purified to homogeneity. The purified enzyme is a tetrameric protein (180 kDa) corresponding to the association of four lipase molecules. The 15 N-terminal amino acid residues showed a high degree of homology with other staphylococcal lipase sequences. The part of the gene encoding the mature SAL3 is cloned and sequenced. The deduced polypeptide sequence, corresponding to the mature SAL3, was very similar to the mature Staphylococcus simulans lipase sequence with two additional amino acid residues (LK) at the N-terminus of SAL3. The lipase activity is maximal at pH 9.5 and 55 °C. The specific activity of about 4200 U/mg or 3500 U/mg was measured using tributyrin or olive oil emulsion as substrate, respectively, at pH 9.5 and 55 °C.In contrast to other staphylococcal lipases previously characterised, SAL3 is found to be stable between pH 5 and 12 after 24 h incubation. The enzyme retained 50% of its activity after 60 min incubation at 60 °C. This novel lipase is able to hydrolyse its substrate in presence of various oxidizing agents as well as some surfactants and some commercial detergents, then SAL3 can be considered as a good candidate for industrial and biotechnological applications. 相似文献
158.
Inhibition of pancreatic and microbial lipases by proteins 总被引:2,自引:0,他引:2
We have compared the effect of several proteins, including melittin, beta-lactoglobulin A, serum albumin, ovalbumin and myoglobin, on the hydrolysis of tributyrin and triolein by lipases from various origins. All proteins tested inactivate pancreatic lipase in absence of colipase and bile salt. Inhibition is not significantly reversed by colipase in absence of bile salt except in systems containing tributyrin and melittin or triolein and beta-lactoglobulin A. In all other cases, activation of pancreatic lipase by colipase in presence of inhibitory protein requires the presence of bile salt. Lipase from Rhizopus delemar is also inhibited by the proteins that inactivate pancreatic lipase. In contrast, the activity of lipase from Rhizopus arrhizus is not affected by the proteins in the same concentration range. Inhibition of lipase activity by amphiphiles such as proteins or detergents appears to be a general phenomenon not directly related to a decrease in tension at the triacylglycerol-water interface. Inhibition could be the result of desorption of lipase from its substrate due to a change in interfacial quality. 相似文献
159.
Antibodies against synthetic oligopeptides allow identification of the mRNA-maturase encoded by the second intron of the yeast cob-box gene. 总被引:3,自引:2,他引:1 下载免费PDF全文
N Guiso M Dreyfus O Siffert A Danchin A Spyridakis A Gargouri M Claisse P P Slonimski 《The EMBO journal》1984,3(8):1769-1772
Genetic and biochemical evidence has strongly suggested that several introns located in yeast mitochondrial genes specifying apocytochrome b or cytochrome oxidase encode trans-acting proteins (termed mRNA-maturases) responsible for splicing the cognate intron and maturation of the mRNA. We have chemically synthesized three oligopeptides, predicted from the DNA sequence of the open reading frame (ORF) present in the second intron of the cob-box gene, and raised antibodies against them. These antibodies have allowed us to identify a protein of 42 kd as the product translated from the ORF of the wild-type intron. In two splicing-deficient mutants this protein is replaced by shorter polypeptides whose lengths and antigenic properties are in full agreement with the positions of TAA codons established by the DNA sequence of the intron's ORF. 相似文献
160.
H Moreau A Bernadac N Trétout Y Gargouri F Ferrato R Verger 《European journal of cell biology》1990,51(1):165-172
Lipase and pepsin activities were determined in rabbit gastric biopsy specimens. Lipase activity was found to be restricted to a small part of the fundic mucosa, near the cardia, whereas pepsin activity spread over about two thirds of the total fundic area, overlapping that of lipase. The cells producing these two enzymes were labeled by immunofluorescence using polyclonal antibodies against rabbit gastric lipase (RGL) or antibodies against rabbit pepsinogen. The immunocytochemical localization showed unequivocally that RGL and pepsinogen, which were both present in the cardial area, were in fact located in different gastric cells. The cells producing pepsinogen were in the lower base of the gastric fundic glands, whereas the cells producing RGL were in the upper base of the same glands. The cells producing pepsinogen and RGL showed no significant morphological differences. In the part of the fundic area, where only pepsin activity was detected, cells producing pepsinogen covered both the lower and the upper base of the gastric glands. No chief cells were observed in the antral mucosa. RGL and pepsinogen could represent useful gastric enzyme markers for cellular differentiation studies. 相似文献