Search results for "interactions."
showing 10 items of 1865 documents
Penser la ville durable : positionner la modélisation et l’évaluation des territoires dans les processus d’aménagement
2015
National audience; Les politiques d’aménagement du territoire sont guidées depuis deux décennies par les objectifs du développement durable. Én¬oncé dans le rapport de G.H. Brundtland (1987) réalisé pour le compte des Nations-Unies, l’expression « développement du¬rable » définit en effet un « développe¬ment qui répond au besoin du présent sans compromettre la capacité des généra¬tions futures à satisfaire leurs propres be¬soins ». Trois sphères distinctes mais qui se chevauchent sont identifiées, dans les¬quelles les principes de développement du¬rable doivent être appliqués : l’économique, le social et l’environnemental, la combi¬naison des trois faisant théoriquement at¬teindre le niveau…
Arbuscular mycorrhizal fungi positively affect growth of Ailanthus altissima (Mill.) Swingle seedlings and show a strong association with this invasi…
2015
Arbuscular mycorrhizal fungi (AMF) may promote plant invasion by enhancing plant performance and competitiveness. However, only a small number of studies have considered the interactions between local soil microbial communities and invasive plants, and even fewer have focused on alien trees. Ailanthus altissima is a serious problem in the Mediterranean Basin, where it has invaded many habitats. We investigated the symbiosis between A. altissima and indigenous AMF in two invaded, ecologically different Mediterranean woodlands. Mycorrhizal infection was high at both sites (> 60% of the root fragments were mycorrhizal), indicating that A. altissima roots may be infected by AMF under different …
Aroma release in the oral cavity after wine intake is influenced by wine matrix composition
2018
The aim of this study has been to investigate if wine matrix composition might influence the interaction between odorants and oral mucosa in the oral cavity during a “wine intake-like” situation. Aroma released after exposing the oral cavity of three individuals to different wines (n = 12) previously spiked with six target aromas was followed by an -in vivo intra-oral SPME approach. Results showed a significant effect of wine matrix composition on the intra-oral aroma release of certain odorants. Among the wine matrix parameters, phenolic compounds showed the largest impact. This effect was dependent on their chemical structure. Some phenolic acids (e.g. hippuric, caffeic) were associated t…
THE BEHAVIORAL RESPONSE OF AMPHIPODS HARBORING CORYNOSOMA CONSTRICTUM (ACANTHOCEPHALA) TO VARIOUS COMPONENTS OF LIGHT
2006
Many studies have shown that photic behavior of amphipods is subject to parasitic manipulation. However, all these investigations have focused on but one property of light (i.e., intensity). This study investigated the possibility that variable wavelength sensitivity, as a potentially important component of amphipod ecology, is subject to parasitic manipulation. The photic behavior of freshwater amphipods Hyalella azteca, infected with the duck acanthocephalan Corynosoma constrictum, was tested. The phototactic responses of infected and uninfected amphipods to various wavelengths in the visible spectrum were compared, and to delineate the effects of intensity and wavelength on behavior, the…
Carotenoids of two freshwater amphipod species (Gammarus pulex and G. roeseli) and their common acanthocephalan parasite Polymorphus minutus
2004
Carotenoid compositions of two freshwater Gammarus species (Crustacea: Amphipoda) and of their common acanthocephalan parasite Polymorphus minutus were characterized. The effect of carotenoid uptake by the parasite was addressed by comparing the carotenoid content of uninfected and infected female hosts. Using high-pressure liquid chromatography (HPLC), co-chromatography of reference pigments and electron ionization mass spectrometry of collected HPLC fractions (EI-MS), several xanthophylls and non-polar compounds were identified. Seven kinds of carotenoids, mainly xanthophylls, were identified in gammarids. Astaxanthin was predominant, amounting to 40 wt.% of total carotenoid in both uninf…
Micro-organisms interactome during wine alcoholic fermentation
2022
The study of interactions between microorganisms is of major interest in oenology for various applications, including the modulation of the aromatic profile of wines. The interactions between Saccharomyces and non-Saccharomyces yeasts are widely described in the literature. On the contrary, interactions during alcoholic fermentation between S. cerevisiae strains, known for their technological properties in oenology, have been little studied.In this work, twelve strains of S. cerevisiae and their impact on wine were characterized in pure cultures using an integrative approach that combines microbiological, chemical, metabolomic and sensory approaches. An important intraspecific diversity was…
Cercarial Production of the Trematode Rhipidocotyle fennica in Clams Kept in the Field
1998
The numbers of cercariae that trematodes produce have been previously investigated in the laboratory but not in the field. I studied cercarial production of the bucephalid trematode Rhipidocotyle fennica in the freshwater unionid clam Anodonta piscinalis kept under natural conditions. Naturally infected clams (n = 180) were collected and marked in early June 1996. Every 14 days, starting from the collection date and ending in October, these clams were taken to the laboratory where they were monitored for the emergence of trematode cercariae. Between monitoring dates, the clams were returned to the collection site. From a random subsample of infected clams (n = 12), the number of cercariae p…
Relatedness affects competitive performance of a parasitic plant (Cuscuta europaea) in multiple infections.
2004
Theoretical models predict that parasite relatedness affects the outcome of competition between parasites, and the evolution of parasite virulence. We examined whether parasite relatedness affects competition between parasitic plants (Cuscuta europaea) that share common host plants (Urtica dioica). We infected hosts with two parasitic plants that were either half-siblings or nonrelated. Relative size asymmetry between the competing parasites was significantly higher in the nonrelated infections compared to infections with siblings. This higher asymmetry was caused by the fact that the performance of some parasite genotypes decreased and that of others increased when grown in multiple infect…
Stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles-metal organic framework composite: Determination of N-nitrosamines in…
2019
Abstract A new analytical method based on the recently proposed stir bar sorptive-dispersive microextraction (SBSDME) technique has been developed to determine eight hazardous N-nitrosamines in cosmetic products. As previous step, a simple clean-up is carried out with hexane to remove those highly lipophilic compounds that disturb the SBSDME step. Subsequently, SBSDME is performed by using magnetic nanoparticles–metal organic framework composite, CoFe2O4/MIL-101(Fe), as sorbent to entrap the target analytes, which are later chemically desorbed and measured by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The experimental variables related to the SBSDME procedure were studied to…
Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutic…
2007
[EN] The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil…