排序方式: 共有63条查询结果,搜索用时 15 毫秒
1.
Youssef Arfaoui Mohamed Lotfi Efrit Néji Besbes 《Journal of molecular modeling》2013,19(10):4603-4612
The mechanism of the thermal rearrangement of substituted N-acyl-2,2-dimethylaziridines 1 has been studied using quantum chemistry methods. Geometries of reactants, transition states and products have been optimized at the B3LYP/6-311++G(2d,2p) level. Relative energies for various stationary points have been determined and reaction identified by IRC calculations. The results show that thermal rearrangements occur in three ways. Firstly, the transition state TS 1 in which a hydrogen atom of methyl groups migrates from primary carbon to oxygen of amid group to give the N-methallylamide 2. The second is via the transition state TS 2 in which the attack of oxygen to the tertiary carbon yields the oxazoline 3. The third is via the transition state TS 3 in which a hydrogen migrate from the secondary carbon to oxygen to give the vinylamide 4. In order to get insights into the factors determining the exact nature of its interactions with electrophiles, the application of reactivity parameters derived from density functional theory in a local sense, in particular the softness and Fukui function, to interpret and predict the mechanisms of the thermal decomposition of the N-acyl-2,2-dimethylaziridines 1, has been discussed. 相似文献
2.
Faten Talmoudi Olfa Kilani Wiem Ayed Nizar Ben Halim Fethi Mellouli Lamia Torjmane Lamia Aissaoui Yosra Ben Youssef Lobna Kammoun Tarek Ben Othmane Mohamed Bejaoui Neila Ben Romdhane Moez Elloumi Sondes Hadiji Sofiene Hentati Imene Chemkhi Nabila Abidli Helmi Guermani Sonia Abdelhak Ahlem Amouri 《Comptes rendus biologies》2013,336(1):29-33
Fanconi anemia (FA) is a recessive chromosomal instability syndrome that is clinically characterized by multiple symptoms. Chromosome breakage hypersensitivity to alkylating agents is the gold standard test for FA diagnosis. In this study, we provide a detailed laboratory protocol for accurate assessment of FA diagnosis based on mitomycin C (MMC) test. Induced chromosomal breakage study was successful in 171 out of 205 aplastic anemia (AA) patients. According to the sensitivity of MMC at 50 ng/ml, 38 patients (22.22%) were diagnosed as affected and 132 patients (77.17%) as unaffected. Somatic mosaicism was suspected in an 11-year-old patient with a FA phenotype. Twenty-six siblings of FA patients were also evaluated and five of them (19.23%) were diagnosed as FA. From this study, a standard protocol for diagnosis of FA was developed. It is routinely used as a diagnostic test of FA in Tunisia. 相似文献
3.
Haythem Gharsa Karim Ben Slama Elena Gómez-Sanz Carmen Lozano Naouel Klibi Ahlem Jouini Lilia Messadi Abdellatif Boudabous Carmen Torres 《Microbial ecology》2013,66(2):363-368
Nasal swabs of 100 healthy dogs were obtained in 2011 in Tunisia and tested for Staphylococcus pseudintermedius recovery. Antimicrobial resistance profile and virulence gene content were determined. Multilocus-sequence-typing (MLST) and SmaI-pulsed-field gel electrophoresis (PFGE) were investigated. S. pseudintermedius was recovered in 55 of the 100 tested samples (55 %), and one isolate per sample was further studied. All 55 S. pseudintermedius isolates were susceptible to methicillin (MSSP) but showed resistance to the following antimicrobials (% resistant isolates/resistance gene): penicillin (56.4/blaZ), tetracycline (40/tetM), trimethoprim-sulfamethoxazole (23.7), fusidic acid (9), kanamycin (3.7/aph(3´)-Ia), erythromycin-clindamycin (1.8/erm(B)), streptomycin (1.8/ant(6)-Ia), chloramphenicol (1.8) and ciprofloxacin (1.8). The following toxin genes were identified (% of isolates): lukS/F-I (98.2), expA (5.5), se-int (98.2), sec canine (1.8), siet (100), sea (5.5), seb (3.6), sec (10.9), sed (54.5), sei (5.5), sej (29.1), sek (3.6), ser (9.1), and hlg v (38.2). Ten different sequence-types were detected among 11 representative MSSP isolates: ST20, ST44, ST69, ST70, ST78, ST100, ST108, ST160, ST161, and ST162, the last three ones revealing novel alleles or allele combinations. Eleven different PFGE-patterns were identified in these isolates. The nares of healthy dogs could be a reservoir of antimicrobial resistant and virulent MSSP, highlighting the presence of the recently described exfoliating gene expA and several enterotoxin genes. 相似文献
4.
5.
This study aimed to improve understanding of the strategies developed by the Mediterranean seaweed Taonia atomaria to chemically control bacterial epibiosis. An experimental protocol was optimized to specifically extract algal surface-associated metabolites by a technique involving dipping in organic solvents whilst the integrity of algal cell membranes was assessed by fluorescent microscopy. This methodology was validated using mass spectrometry-based profiles of algal extracts and analysis of their principal components, which led to the selection of methanol as the extraction solvent with a maximum exposure time of 15 s. Six compounds (A–F) were identified in the resulting surface extracts. Two of these surface-associated compounds (B and C) showed selective anti-adhesion properties against reference bacterial strains isolated from artificial surfaces while remaining inactive against epibiotic bacteria of T. atomaria. Such specificity was not observed for commercial antifouling biocides and other molecules identified in the surface or whole-cell extracts of T. atomaria. 相似文献
6.
Biocontrol of Fusarium Wilt and Growth Promotion of Tomato Plants Using Endophytic Bacteria Isolated from Solanum elaeagnifolium Stems
下载免费PDF全文
![点击此处可从《Journal of Phytopathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rania Aydi Ben Abdallah Hayfa Jabnoun‐Khiareddine Ahlem Nefzi Sonia Mokni‐Tlili Mejda Daami‐Remadi 《Journal of Phytopathology》2016,164(10):811-824
Seven culturable bacterial isolates, obtained from the internal stem tissues of Solanum elaeagnifolium and successfully colonizing the internal stem tissues of tomato cv. Rio Grande, were screened for their in vivo antifungal activity against Fusarium oxysporum f.sp. lycopersici (FOL) and their growth‐promoting potential on tomato plants. SV101 and SV104 isolates, assessed on pathogen‐challenged tomato plants led to a significant decrease (77–83%) in Fusarium wilt severity and vascular browning extent (76%), as compared to the inoculated and untreated control. Isolates enhanced growth parameters on pathogen‐challenged and unchallenged tomato plants. SV104 and SV101 isolates were most effective in suppressing disease and enhancing plant growth. These two isolates were identified as Bacillus sp. str. SV101 ( KU043040 ) and B. tequilensis str. SV104 ( KU976970 ). They displayed antifungal activity against FOL; pathogen growth was inhibited by 64% and an inhibition zone (11.50 and 19.75 mm) against FOL could be formed using whole cell suspensions. SV101 and SV104 extracellular metabolites also inhibited FOL growth by 20 and 55%, respectively, as compared to control. B. tequilensis str. SV104 was shown to produce protease, chitinase, pectinase, IAA and siderophores. Bacillus sp. str. SV101 displayed pectinase activity and was found to be an IAA‐producing and phosphate‐solubilizing agent. To our knowledge, this is the first study reporting on S. elaeagnifolium use as a potential source of potent biocontrol and plant growth‐promoting agents. 相似文献
7.
Jamal S.M. Sabir Abdelfatteh El Omri Noor A. Shaik Babajan Banaganapalli Nahid H. Hajrah Houda Zrelli Leila Arfaoui Zuhier A. Awan Abdulkader M. Shaikh Omar Arif Mohammed Mona G. Alharbi Alawiah M. Alhebshi Robert K. Jansen Muhummadh Khan 《Saudi Journal of Biological Sciences》2019,26(7):1338-1343
Obesity is a multifactorial metabolic disorder characterized by low grade chronic inflammation. Rare and novel mutations in genes which are vital in several key pathways have been reported to alter the energy expenditure which regulates body weight. The TP53 or p53 gene plays a prominent role in regulating various metabolic activities such as glycolysis, lipolysis, and glycogen synthesis. Recent genome-wide association studies reported that tumor suppressor gene p53 variants play a critical role in the predisposition of type 2 diabetes and obesity. Till date, no reports are available from the Arabian population; hence the present study was intended to assess the association between p53 variants with risk of obesity development in the Saudi population. We have selected three p53 polymorphisms, rs1642785 (C > G), and rs9894946 (A > G), and rs1042522 (Pro72Arg; C > G) and assessed their association with obesity risk in the Saudi population. Phenotypic and biochemical parameters were also evaluated to check their association with p53 genotypes and obesity. Genotyping was carried out on 136 obese and 122 normal samples. We observed that there is significantly increased prevalence p52 Pro72Arg (rs1042522) polymorphism in obese persons when compared to controls at GG genotype in overall comparison (OR: 2.169, 95% CI: 1.086-4.334, p = 0.02716). Male obese subjects showed three-fold higher risk at GG genotype (OR: 3.275, 95% CI: 1.230-8.716, p = 0.01560) and two-fold risk at G allele (OR: 1.827, 95% CI: 1.128-2.958, p = 0.01388) of p53 variant Pro72Arg respectively. This variant has also shown significant influence on cholesterol, LDL level, and random insulin levels in obese subjects (p ≤ 0.05). In conclusion, p53 Pro72Arg variant is highly prevalent among obese individuals and may act as a genetic modifier for obesity development among Saudis. 相似文献
8.
Ben Sassi A Harzallah-Skhiri F Borgi W Chouchène N Aouni M 《Comptes rendus biologies》2007,330(3):226-230
The effect of the methanolic extract of flowers of Chrysanthemum trifurcatum (Desf.) Batt. and Trab. Var. macrocephalum (viv.) Beg. on the rat duodenum smooth muscle motility was examined in vitro. The extract has shown dose-dependent stimulator effects on the amplitude of the spontaneous contractions. With 0.1 g/ml of extract, maximal stimulation was obtained. With that dose, the variation (%) was significantly 1050 +/- 13 (P<0.001) compared with control and represented 80 +/- 5.83% (P<0.001) of the maximum effect of acetylcholine. Atropine (2 microg/ml) reduced by 81 +/- 4% (P<0.05) the spasmogenic effects of C. trifurcatum and by 92 +/- 3% (P<0.05) the acetylcholine effects, while papaverine (2 microg/ml) completely inhibited the spasmogenic effects of extract. With a fixed dose of acetylcholine added (20 microg/ml), the extract increases its effect, but acetylcholine decreases its action. These results suggested that the methanolic extract of C. trifurcatum could stimulate duodenal smooth muscle contractions through muscarinic receptors. Thy explain the respective traditional use of plant in gastrointestinal problems, especially constipation. 相似文献
9.
Bouchlaka C Othman TB Aissaoui L Elloumi H Elloumi M Amouri A Abid HB Hadiji S Slama H Makni H Saad A Abdelhak S Dellagi K;Tunisian Fanconi Anemia Study Group 《Genetic testing》2004,8(3):268-275
We report on the effectiveness of molecular studies regarding Fanconi anemia (FA) for a better selection of bone marrow graft donors and for post-transplant follow up. Ten unrelated FA patients and their families were analyzed by microsatellite markers. In 9 cases, the cytogenetic investigation of potential human leukocyte antigen (HLA)-identical related donors was normal, and the molecular analyses confirmed that they were also either normal or heterozygous carriers. For 1 patient, cytogenetic analysis of an HLA-identical sibling donor yielded ambiguous results with a relatively high number of chromosomal breakages using cross-linking agents. However, genotyping of this potential donor demonstrated his heterozygous state. Nine patients have received allogeneic bone marrow transplantation from HLA-matched related donors. Microsatellite analysis showed complete chimerism (CC) in all cases. The median follow up was 54 months (range 8-144 months). One patient out of 9 with CC rejected her graft without prior detection of a transitional mixed chimerism. Among these patients, 1 died 25 months after the transplantation of a chronic graft-versus-host-disease (GVHD). We conclude that, when the cytogenetic studies are not conclusive, molecular analyses are crucial to distinguish heterozygous carriers from asymptomatic FA Tunisian patients. Molecular analyses also allowed the evaluation of hematopoietic chimerism after allogeneic bone marrow transplantation and might be of value to identify patients with a high risk for graft rejection. 相似文献