Search results for "Porte"
showing 10 items of 1894 documents
Role of the non-infective stage of the acanthocephalan parasite Pomphorhychus laevis on the behavioural manipulation of its amphipod intermediate host
2012
In trophically-transmitted parasites, exploitation strategies of the intermediate host have been selected, in a way increasing parasites transmission probabilities to their definitive host. Particularly, numerous parasites are able to alter their intermediate host behaviour, a phenomenon called ‘behavioural manipulation’. This manipulation only occurs when the parasite developmental stage (or larval stage) is infective for the definitive host. Before reaching this stage, the development of parasite larvae is not sufficiently advanced to allow establishment in the definitive host (this stage is thus called ‘non-infective’). Early transmission of a non-infective stage therefore implies parasi…
Astrocytes and hypothalamic glucose sensing: metabolic role and involvement of astroglial connexins
2012
The hypothalamus plays a pivotal role in the nervous control of glucose homeostasis. This area contains gluco-sensitive neurons. Some of them detect increases in glucose levels and regulate glucose homeostasis by stimulating insulin secretion or inhibiting food intake. It is widely accepted that astrocytes are metabolically coupled to neurons. Lactate, resulting from the metabolism of glucose by astrocytes, is transported via the monocarboxylate transporters (MCTs). In addition, gap junctions (GJ), that form networks within astrocytes, are essential to transfer glucose from the bloodstream to the active neurons. These astroglial GJ mainly consist of connexins 43 and 30 (Cxs).The aims of my …
Les comportements préalables à la prise lactée chez le souriceau : caractérisation de sécrétions maternelles réactogènes et implication de l'expérien…
2012
Birth is one of the most delicate periods mammalian infants have to deal with. Newborns have then to adapt physiologically and behaviorally to the aerial environment, and one of their first challenges is to ingest colostrum and milk. It is paradoxical that the survival of pups is conditioned by the success of this first suckling, and that we have so little understanding of the stimuli that underlie and promote it. Thus, the present work aims to contribute to answer how immature and naïve newborns do manage to orient to a nipple, to grasp it, and to suckle efficiently? This general issue will be addressed in the mouse in focusing on: i) the nature of the chemical substrates that newborn mice…
Olfactory neurons plasticity : environment effects during development
2012
In order to investigate the consequences of postnatal odorant exposure on a specific population of olfactory sensory neurons (OSNs), we have taken the following experimental approach. MOR23-GFP mice were daily exposed to Lyral for 21 days starting at birth and three lines of investigations were carried out. Using anatomical analysis we observe that the density of OSNs expressing MOR23 decreases after odorant exposure. This decrease concerns primarily matures OSN (MOR23-OMP+). In order to study molecular changes within individual OSNs, mRNA levels for olfactory signaling pathway components were quantitatively analyzed using qPCR on GFP-labeled neurons (7 per mouse). mRNAs for CNGA2, PDE1C an…
Understanding the low consumption of pulses among French non vegetarian consumers : combining direct and indirect approaches to identify barriers and…
2020
The objective of this thesis was to understand the barriers related to the consumption of pulses by French non-vegetarian consumers, by combining direct, indirect and implicit approaches.After showing that the social representations of consumers towards pulses are very different from those of professionals of the industry, we explored the mental representations, beliefs and knowledge about pulses among consumers. We showed that, even if the participants in our study had knowledge regarding pulses, they did not choose them frequently and associated them mostly with meat, which holds the central place of their meal. The difficulty of preparation of pulses seems to be a major obstacle to their…
Olfactory neurons plasticity : environment effects during development
2012
In order to investigate the consequences of postnatal odorant exposure on a specific population of olfactory sensory neurons (OSNs), we have taken the following experimental approach. MOR23-GFP mice were daily exposed to Lyral for 21 days starting at birth and three lines of investigations were carried out. Using anatomical analysis we observe that the density of OSNs expressing MOR23 decreases after odorant exposure. This decrease concerns primarily matures OSN (MOR23-OMP+). In order to study molecular changes within individual OSNs, mRNA levels for olfactory signaling pathway components were quantitatively analyzed using qPCR on GFP-labeled neurons (7 per mouse). mRNAs for CNGA2, PDE1C an…
Réponses comportementales et préférences envers les acides gras à longue chaîne chez Drosophila melanogaster
2011
Fatty-acids (FAs) are crucial for animal survival and reproduction since these molecules are involved in many metabolic pathways and constitute a substantial store of energy. Despite the strong relationship established between excessive FA consumption and severe human etiologies (obesity, cancer, vascular diseases), our knowledge of the mechanisms underlying FA perception and preference is limited particularly in invertebrates. This is one of the reasons why we decided to investigate, during our PhD thesis, the perception of long-chain FAs (C14:0, C16:0, C18:0, C18:1, C18:2, C18:3), using the model species Drosophila melanogaster. We have also attempted to characterize some of the biologica…
Mieux comprendre le dépérissement du 161-49C
2021
Arbuscular mycorrhiza (AM): the first glomeromycotan sugar transporter is characterized by using the unique geosiphon symbiosis with cyanobacteria to…
2007
International audience; In the arbuscular mycorrhizas (AM), the symbiotic interface is the site of nutrient exchange where the mycobiont receives up to 20% of the photosynthates of the photobiont as carbohydrates. We have, for the first time, functionally characterised a monosaccharide transporter type, represented by GpMST1, putatively playing a role in this process (Schüßler, A., Martin, H., Cohen, D., Fitz, M., and Wipf, D. 2006. Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi. Nature 444:933-936.). Together with the arbuscular mycorrhizal (AM) fungi, forming endomycorrhiza with the majority of land plants, Geosiphon pyriformis belongs to the Glomeromyc…