排序方式: 共有71条查询结果,搜索用时 15 毫秒
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Asma Ait-Kaki Noreddine Kacem-Chaouche Marc Ongena Mounira Kara-Ali Laid Dehimat Karima Kahlat Philippe Thonart 《Applied biochemistry and biotechnology》2014,172(4):1735-1746
This report is to our knowledge the first to study plant growth promotion and biocontrol characteristics of Bacillus isolates from extreme environments of Eastern Algeria. Seven isolates of 14 (50 %) were screened for their ability to inhibit growth of some phytopathogenic fungi on PDA and some roots exudates. The bacteria identification based on 16S r-RNA and gyrase-A gene sequence analysis showed that 71 % of the screened isolates belonged to Bacillus amyloliquefaciens and the rest were closely related to B. atrophaeus and B. mojavensis. Most of them had high spore yields (22?×?108–27?×?108 spores/ml). They produced protease and cellulase cell wall-degrading enzymes while the chitinase activity was only observed in the B. atrophaeus (6SEL). A wide variety of lipopeptides homologous was detected by liquid chromatography–electrospray ionization–mass spectrometry analysis. Interestingly, some additional peaks with new masses were characterized, which may correspond to new fengycin classes. The isolates produced siderophores and indole-3- acetic acid phytohormone. The greenhouse experiment using a naturally infested soil with Sclerotonia sclerotiorum showed that the B. atrophaeus (6SEL) significantly increased the size of the chickpea plants and reduced the stem rot disease (P?<?0.05). These results suggest that these isolates may be used further as bio-inoculants to improve crop systems. 相似文献
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Achelhi K Masse S Laurent G Roux C Laghzizil A Saoiabi A Coradin T 《Langmuir : the ACS journal of surfaces and colloids》2011,27(24):15176-15184
Zirconia-hydroxyapatite nanocomposites were prepared by sol-gel deposition of zirconium oxide from a zirconium alkoxide in the presence of apatite colloidal suspension under ultrasonication. The material porosity evolves from mainly microporous zirconia to mesoporous hydroxyapatite, with decreasing surface area and increasing pore volume. XRD studies indicate that the apatite phase is well-preserved within the composite materials. The homogeneous dispersion of apatite colloids within the zirconia network was supported by TEM observations and nitrogen sorption measurements. (31)P solid-state NMR studies suggest that partial dissolution of apatite may have occurred during the preparation, leading to the adsorption of phosphate species on zirconia particles. This is confirmed by XRD studies of nanocomposites after thermal treatment that demonstrate the preferred formation of tetragonal over monoclinic ZrO(2) in the presence of hydroxyapatite. In order to investigate the surface properties of these novel materials, the adsorption of Pb(2+), Cr(3+), and Cr(2)O(7)(2-) was evaluated. Metal cations were preferentially adsorbed on apatite-rich composites, whereas Cr(2)O(7)(2-) shows a good affinity for the zirconia-rich phases. Zirconia-apatite materials showed the most promising performance in terms of recyclability. These nanocomposites that combine microporosity, mesoporosity and dual sorption properties for these species appear as interesting materials for metal ion remediation and may also find applications as biomaterials. 相似文献
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Nassima Leulmi Denise Sighel Andrea Defant Karima Khenaka Abderrahmane Boulahrouf 《Natural product research》2019,33(2):266-273
The present work describes the metabolites produced by a strain identified as Streptomyces youssoufiensis, whose secondary metabolites profile has not been studied so far. The crude ethyl acetate extract was analyzed by high performance liquid chromatography-electrospray ionization mass spectrometry, leading to the detection of the ionophoric polyethers nigericin, epinigericin, abierixin and the newly isolated grisorixin methyl ester. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred density functional theory computational calculations. This analysis was able to provide the relative stability of the most favored epimers, setting the basis for general structural considerations applicable to several other polyethers. Both nigericin sodium salt and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (GI50 values of 3.85 and 3.05 μM for VIPI and COMI human glioblastoma stem cells, respectively). 相似文献
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Adrián Fontana-Escartín Karima El Hauadi Sonia Lanzalaco Maria M. Pérez-Madrigal Elaine Armelin Pau Turon Carlos Alemán 《Macromolecular bioscience》2023,23(9):2300024
Virtually, all implantable medical devices are susceptible to infection. As the main healthcare issue concerning implantable devices is the elevated risk of infection, different strategies based on the coating or functionalization of biomedical devices with antiseptic agents or antibiotics are proposed. In this work, an alternative approach is presented, which consists of the functionalization of implantable medical devices with sensors capable of detecting infection at very early stages through continuous monitoring of the bacteria metabolism. This approach, which is implemented in surgical sutures as a representative case of implantable devices susceptible to bacteria colonization, is expected to minimize the risk of worsening the patient's clinical condition. More specifically, non-absorbable polypropylene/polyethylene (PP/PE) surgical sutures are functionalized with conducting polymers using a combination of low-pressure oxygen plasma, chemical oxidative polymerization, and anodic polymerization, to detect metabolites coming from bacteria respiration. Functionalized suture yarns are used for real-time monitoring of bacteria growth, demonstrating the potential of this strategy to fight against infections. 相似文献
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One-dimensional indexed bilinear (BL) models are widely used for modeling non Gaussian time series. Extending BL models to multidimensional indexed (spatial) SBL one, yields a novel class of models which are capable of taking into account the important characteristic of non Gaussianity and spatiality behavior. Our main contribution here is to extend various results on BL processes to SBL one. Our attention is thus focussed on the probabilistic structure of some SBLmodels. So, we establish necessary and sufficient conditions for the existence of regular stationary and ergodic solutions in term of their transfer functions. As a consequence, we observe that the second order structure is similar to a spatial ARMA model with some uncorrelated white noise. So, it is necessary to look into higher-order moments in order to distinguish between linear and nonlinear random fields. Our study may be applied to GARCH or ARMA random fields. 相似文献
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A sensitive and selective spectrofluorimetric method has been developed for flow injection analysis (FIA) of iron(III) based
on its fluorescence quenching effect on the water soluble 1-naphthol-2-sulfonate. The fluorescence emission spectra were collected
with excitation at 283 nm. The emission peaks of the neutral and anionic forms of 1-naphthol-2-sulfonate as well as the band
area were found to decrease linearly with iron(III) concentrations over the range 0.1–18 μg ml−1 and a detection limit of 3.4 ng ml−1 (emission at 349 nm) with FIA. Possible interferences from different cations and anions, which could affect the analytical
response, are evaluated and showed the high selectivity of the method. The effect of solution pH and 1-naphthol-2-sulfonate
concentration were examined and the reaction conditions are optimized. The method is successfully applied to determine iron(III)
in industrial effluents from different sources without any complications with recoveries of almost 100% with both manual and
flow injection methods. Results were found to be very consistent with those obtained using atomic absorption spectrometry. 相似文献
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Fazia Derridj Karima Si Larbi Julien Roger Safia Djebbar Henri Doucet 《Tetrahedron》2012,68(36):7463-7471
The palladium-catalyzed direct arylation at C2 or C5 of free NH2 substituted thiophene derivatives was found to proceed in moderate to high yields using a variety of aryl halides. The choice of potassium acetate as the base was found to be crucial to inhibit the amination reaction and to promote the direct arylation. 相似文献
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