Search results for "molécula"
showing 10 items of 109 documents
Genetic evidence confirms polygamous mating system in a crustacean parasite with multiple hosts.
2014
Mating systems are diverse in animals, notably in crustaceans, but can be inferred from a limited set of parameters. Baeza and Thiel (2007) proposed a model predicting mating systems of symbiotic crustaceans with three host characteristics and the risk of predation. These authors proposed five mating systems, ranging from monogamy to polygynandry (where multiple mating occurs for both genders). Using microsatellite loci, we tested the putatively mating system of the ectoparasite crab Dissodactylus primitivus. We determined the mating frequencies of males and females, parentage assignment (COLONY & GERUD software) as well as the contents of female spermathecae. Our results are globally consi…
La matriz extracelular: morfología, función y biotensegridad (parte I)
2009
La matriz extracelular (MEC) representa una red tridimensional que engloba todos los órganos, tejidos y células del organismo. Constituye un filtro biofísico de protección, nutrición e inervación celular y el terreno para la respuesta inmune, angiogénesis, fibrosis y regeneración tisular. Y representa el medio de transmisión de fuerzas mecánicas a la membrana basal, que a través de las integrinas soporta el sistema de tensegridad y activa los mecanismos epigenéticos celulares. La alteración de la MEC supone la pérdida de su función de filtro eficaz, nutrición, eliminación, denervación celular, pérdida de la capacidad de regeneración y cicatrización y alteración de la transmisión mecánica o …
Study of the different polymorphs of alumina and transitional phases appearing in the first oxidation stage of aluminium : simulation at the atomic s…
2014
The goal of this work is to develop a new SMTB-Q potential in order to study the early stages of the oxidation of aluminium by molecular dynamics (MD).Our potential is able to model different alumina polymorphs as well as transitions from the amorphous state to a crystalline phase. Our approach couples a covalent term with the charge. It uses Rapp_ and Goddard scheme for the electrostatic part and the model of alternating network developed by C. Noguera for the covalent part.The SMTB-Q potential was validated with a Monte Carlo approach. This study shows that the potential SMTB-Q gives satisfactory results for the Al-O bonding in different atomic configurations. The bonding results from the…
Molecular simulation of mixed gas hydrates in astrophysical conditions
2020
In this PhD work, numerical simulation methods have been used in order to model clathrate hydrates at the molecular scale, in thermodynamic conditions typical of astrophysical contexts. The aim was to characterize the trapping abilities of those peculiar structures of water, by means of the tools used in adsorption studies. The results presented in the present thesis are focused on a couple of chemical species which are found to be abundant in our astrophysical vicinity and are quite similar: carbon monoxide, CO, and nitrogen, N2. Thus, the single-component clathrates of CO and N2, and the mixed hydrate CO-N2 have been studied, mainly using grand canonical Monte Carlo simulations. First, th…
Development of functionalizable azaBODIPYs for the conception of theranostic agents and bimodal probes for imaging uses
2020
The in vivo use of optical imaging is still limited by the lack of near infrared emitting probes. This thesis work focuses on the optimization and valorization of a water-soluble fluorescent platform whose optical properties enable an in vivo use. Two distinct applications were investigated for this WazaBY (Water-soluble azaBODIPY) platform: use as a PET (or SPECT) / optical bimodal probe, and as a theranostic agent. Concerning the first project, we were able to develop a targetted SPECT/optical bimodal probe, which was radiometallated with indium 111. Using xenografted murine models, we were able to show a clear accumulation of the probe in the tumor 24 hours after injection. Moreover, the…
Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level
2014
Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to …
Fusarium wilt of cyclamen : early detection and biocontrol
2016
Fusarium wilt of cyclamen is one of the most damaging diseases of cyclamen. The causal agent, Fusarium oxysporum f. sp. cyclaminis, is a soil-borne fungus. Losses can reach more than 50 % of the production. Several methods of control are available, but none of them offer an efficient and environmentally friendly solution. In this context, a project was developed in collaboration with the French institute of horticulture, Astredhor, which represents the producers, the INRA of Dijon, for its expertise on F. oxysporum and the company Agrene for its expertise in biological control. The project has two goals: i) design a molecular marker specific of Fusarium oxysporum f. sp. cyclaminis allowing …
Des outils moléculaires toujours plus multifonctionnels pour l’étude de structures alternatives d’acides nucléiques.
2022
G-Quadruplexes (G4) are non-canonical secondary structure found throughout the genome and transcriptome in guanine rich sequences. Their involvement in biologically relevant processes (telomeres maintenance, transcription and translation) has been demonstrated, yet their role is still not fully elucidated. To investigate their role, we focus on the development of biomimetic molecular tools that could be used either to isolate G4 by new generation sequencing techniques or visualize them directly in cell. This class of molecular tools (TASQ: Template Assembled Synthetic Quartet) is composed by four guanine moieties linked to a central template thanks to spacers of different chemical nature. I…
Effects of mutations of wild-type alpha-synuclein on its structure and dimerization and consequences for the Parkinson's disease : answers from coars…
2022
Alpha-synuclein is a protein of 140 amino acids, intrinsically disordered and found abundantly in the brain and whose toxic aggregation there is the hallmark of the Parkinson's disease.The aim of the thesis is to understand the effects of certain mutations on the dimerization of alpha-synuclein and to contribute to understand its involvement in Parkinson's disease by using coarse-grained molecular dynamics. Coarse-grained molecular dynamics trajectories were computed using the UNited-RESidue (UNRES) program and provided unprecedented sampling (over an effective time of the order of milliseconds) of the alpha-synuclein structures in monomeric and dimeric forms. These data were generated both…
Formation de molécules dans des gaz atomiques ultra-froids par des champs quasi-résonnants
2010
We study the nonlinear mean-field dynamics of diatomic molecule formation at coherent photo- and magneto-association of ultracold atoms focusing on the case when the system is initially in the all-atomic state. We show that in the limit of strongly nonlinear interaction between an ultra-cold atomic-molecular system and a quasi-resonant electromagnetic field, the molecule formation process, depending on the characteristics of the associating field, may evolve according two different scenarios, namely, weak- and strong-oscillatory regimes. In the first case the number of molecules increases without pronounced oscillations of atom-molecule populations, while in the second case high-amplitude R…