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131.
Siri N Riolet P Bayle C Couderc F 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,793(1):151-157
We have developed an automated large-volume sample stacking (LVSS) procedure to detect fluorescein isothiocyanate-labeled peptides in the picomolar range. The injection duration is 10 min at 50 mbar to fill 62% of the capillary volume to the detection cell. The calculated limit of detection (S/N=3), filling 1% of the capillary volume, is 74 pM for bradykinin and 45 pM for L-enkephalin with samples diluted in water and analyzed in a 50 mM borate buffer, pH 9.2. With the automated LVSS system, the limits of detection are 7 pM for bradykinin, 3 pM for L-enkephalin and 2 pM for substance P. LVSS is shown to be quantitative from 500 to 10 pM. 相似文献
132.
Plants are attacked, not only by various microorganisms, but also by other enemies, such as molluscs, nematods, mites, and insects. They have evolved complex and efficient mechanisms to defend themselves against pathogens (hypersensitive response, systemic acquired resistance) and herbivores (release of volatile compounds that attract predators of the herbivores, accumulation of proteinase inhibitors). Yet, the confrontation of the plants with their invaders can also turn to the advantage of the latter. In the past, the attacks of crops regularly brought about dramatic economic losses. From the World War II onwards, the development of organic chemistry associated with a growing awareness of the problems of agriculture has resulted in the production of a constantly growing number of plant protection products. They are currently divided into about ten classes, the herbicides, fungicides, and insecticides-acaricides making up more than 90% of the world market. Most of the agrochemical products put on the market over these last three decades are used in relatively low doses and have a more favourable toxicological and ecotoxicological profile than those of the former pesticides, many of which are now withdrawn from the market. Several more or less recent families are derivatives of metabolites from various organisms. Thus, the improvement achieved in the protection of crops is outstanding. However, one on the main side-effect is an environmental imbalance that has entailed a dependency on agrochemicals. Quite judiciously, alternative strategies (elicitors, genetic engineering, etc.) have been initiated or developed over the last decade. 相似文献
133.
The goal of the present study is to construct a biophysical model of the coronary artery endothelial cell response to bradykinin. This model takes into account intracellular Ca2+ dynamics, membrane potential, a non-selective cation channel, and two Ca(2+)-dependent K+ channels, as well as intra- and extracellular Ca2+ sources. The model reproduces the experimental data available, and predicts certain quantities which would be hard to obtain experimentally, like the individual K+ channel currents when the membrane potential is allowed to freely evolve, the implication of epoxyeicosatrienoic acids (EETs), and the total K+ released during stimulation. The main results are: (1) the large-conductance K+ channel participates only very little in the overall response; (2) EETs are required in order to explain the experimental current-potential relationships, but are not an essential component of the bradykinin response; and (3) the total K+ released during stimulation gives rise to a concentration in the intercellular space which is of millimolar order. This concentration change is compatible with the hypothesis that K+ contributes to the endothelium-derived hyperpolarizing factor phenomenon. 相似文献
134.
Isabelle?Blanc Antoine?Bach Yvan?Lallemand Fabienne?Perrin-Schmitt Jean-Louis?Guénet Beno?t?RobertEmail author 《Mammalian genome》2003,14(12):797-804
Pluridigite (Pdt) is a semi-dominant mutation obtained after a mutagenesis experiment with ethyl-nitroso-urea (ENU). The mutant exhibits abnormal skeletal pattern formation characterized by the formation of extra digits (polydactyly) in the preaxial (anterior) part of the hindlimbs. The phenotype shows incomplete penetrance, depending on the genetic background. In an F2 cross with C57BL/6, the phenotype could not be associated with a single locus. Strong linkage was observed with markers located on Chromosome (Chr) 12, in a 2-cM interval between D12Mit136 and D12Mit153. This region contains the Twist gene, and we show that the [Pdt] phenotype is dependent upon a new allele of Twist. We further identified that the whole Chr 4 is associated with the [Pdt] phenotype. The Pluridigite phenotype thus results from the combination of a Twist mutant allele and at least two additional loci. 相似文献
135.
Direct somatic embryogenesis was induced in root tissues of the Cichorium hybrid `474' (C. intybus L. var. sativum×C. endivia L. var. latifolia). Addition of β-d-glucosyl Yariv reagent (βGlcY), a synthetic phenylglycoside that specifically binds arabinogalactan-proteins (AGPs), to the
culture medium blocked somatic embryogenesis in a concentration-dependent manner with complete inhibition of induction occurring
at 250 μM βGlcY. The AGP-unreactive α-d-galactosyl Yariv reagent had no biological activity in this system. Upon transfer of 250 μM βGlcY-treated roots to control
conditions, somatic embryogenesis was recovered with a time course similar to that of control roots. The βGlcY penetrated
roots and bound abundantly to developing somatic embryos, to the root epidermis and the stele. Immunofluorescence and immunogold
labelling using monoclonal antibodies (JIM13, JIM16 and LM2) revealed that AGPs were localised in the outer cell walls peripheral
cells of the globular embryo. A spatio-temporal expression of AGPs appeared to be associated with differentiation events in
the somatic embryo during the transition from the globular stage to the torpedo stage. To verify βGlcY specificity, molecules
that bound βGlcY were extracted from treated conditioned medium and identified as AGPs by using the same monoclonal antibodies.
In addition, AGPs were found to be abundantly present in the medium during embryogenic culture. All of these results establish
the implication of AGPs in embryo development, and their putative role in somatic embryogenesis is discussed.
Received: 26 August 1999 / Accepted: 28 January 2000 相似文献
136.
Fixed response thresholds and the regulation of division of labor in insect societies 总被引:2,自引:0,他引:2
Eric Bonabeau Guy Theraulaz Jean-Louis Deneubourg 《Bulletin of mathematical biology》1998,60(4):753-807
We introduce a simple mathematical model of regulation of division of labor in insect societies based on fixed-response thresholds.
Individuals with different thresholds respond differently to task-associated stimuli. Low-threshold individuals become involved
at a lower level of stimulus than high-threshold individuals. We show that this simple model can account for experimental
observations of Wilson (1984), extend the model to more complicated situations, explore its properties, and study under what
conditions it can account for temporal polyethism. 相似文献
137.
138.
Mònica Campàs Beatriz Prieto-Simón Jean-Louis Marty 《Seminars in cell & developmental biology》2009,20(1):3-9
This article gives an overview of the electrochemical biosensors that incorporate genetically modified enzymes. Firstly, the improvements on the sensitivity and selectivity of biosensors that integrate mutated enzymes are summarised. Next, new trends focused on the oriented immobilisation of mutated enzymes through specific functional groups located at their surface are reviewed. Finally, the effect of enzyme mutations on the electron transfer distance and kinetics of electrochemical biosensors is described. 相似文献
139.
Punnee Pitisuttithum Supachai Rerks-Ngarm Donald Stablein Peter Dawson Sorachai Nitayaphan Jaranit Kaewkungwal Nelson L. Michael Jerome H. Kim Merlin L. Robb Robert J. O’Connell In-Kyu Yoon Stefan Fernandez Jean-Louis Excler 《PloS one》2015,10(5)
RV144 was a community-based HIV vaccine efficacy trial conducted in HIV-uninfected adults in Thailand, where dengue virus continues to cause a large number of infections every year. We attempted to document the accuracy of clinically diagnosed dengue episodes reported as serious adverse events (SAEs) and adverse events (AEs) and examine whether dengue serology would support the clinical diagnosis. Subjects without a clinical dengue diagnosis but with an infection or idiopathic fever were selected as a control population. Dengue serology was performed by hemagglutination inhibition on plasma samples. A total of 124 clinical dengue episodes were reported (103 SAEs and 21 AEs). Overall 82.6% of the clinically diagnosed dengue episodes were supported by a positive dengue serology: 71.4% of the AEs and 85.0% of the SAEs. Of the 100 subjects with both clinical dengue and positive serology, all presented with fever, 83% with leucopenia, 54% with thrombocytopenia, and 27% with hemorrhagic symptoms. All episodes resolved spontaneously without sequellae. Only two of 15 subjects with a negative serology presented with fever. The sensitivity and specificity of clinical dengue diagnosis were 90.9% and 74.4%, respectively, when compared to the control population, and with a positive predictive value of 82.6% and negative predictive value of 84.7% when compared to dengue serology. Clinical diagnosis of dengue is an accurate method of dengue diagnosis in adults in Thailand. Large-scale clinical trials offer the opportunity to systematically study infectious diseases such as dengue and other infections that may occur during the trial. 相似文献
140.
Antoine Millon Monica Sigovan Loic Boussel Jean-Louis Mathevet Vanessa Louzier Christian Paquet Alain Geloen Nicolas Provost Zouher Majd David Patsouris Andre Serusclat Emmanuelle Canet-Soulas 《PloS one》2015,10(11)