Hexadecylphosphocholine interaction with lipid monolayers

AbstractThe phospholipid analogue miltefosine or hexadecylphosphocholine (HePC) is a drug of high interest in the treatment for fatal visceral leishmaniasis (VL) due to Leishmania donovani particularly because of its activity by oral route. In this study, the interaction of HePC with a monolayer of β-palmitoyl-γ-oleyl-phosphatidylcholine (POPC) as membrane model or sterol (ergosterol or cholesterol) was investigated. At a constant pressure of 25 mN/m, the adsorption kinetics of HePC into the monolayers showed that HePC molecules are inserted into the monolayer of lipids as monomers until the critical micellar concentration (CMC). At HePC concentrations superior to the CMC, the micelles of HePC are deployed at the interface as groups of monomers into the POPC or sterol monolayer. The study of mixture of HePC/(POPC or sterol), spread at the air–water interface, shows that a simple miscibility between HePC and POPC is observed, whereas a high condensation appears between HePC and sterols showing a high affinity between HePC and sterols. In addition, HePC does not act as detergent disturbing membrane integrity

cAMP and IP3 signaling pathways in HEK293 cells transfected with canine olfactory receptor genes.

Symposium Issue: Fifth International Conference on Advances in Canine and Feline Genomics and Inherited Diseases, Baltimore, Maryland, 22-25 September 2010. Corrigendum The overweight mixed breed cat photo that appeared as part of the cover for the Symposium issue: Fifth International Conference on Advances in Canine and Feline Genomics and Inherited Diseases, Baltimore, Maryland, 22-25 September 2010 (Issue 102-Supplement 1), was incorrectly identified as mixed breed and attributed to Bianca Haase. The photograph should have been credited to Katherine Parker, and the correct caption should have read as follows: The cover. This special issue of the Journal of Heredity presents the proceedings, of the 5th International Conference on Advances in Canine and Feline Genomics and Inherited Diseases. Photos are of study subjects for several of the research articles in this issue. Clockwise from left: Alaskan sled dogs (photo by Heather Huston), Maine coon cat (photo by Mary Lassaline), West Highland white terrier pups (photo by Joana Barros Roque), overweight Abyssinian cat (photo by Katherine Parker), Pug dogs (photo by Anne Yarbrough Photography) and Shetland sheepdogs (photo by Dayna Dreger). The Editorial Office wish to apologise for this error.International audienceOlfactory receptors (ORs) expressed at the cell surface of olfactory sensory neurons lining the olfactory epithelium are the first actors of events leading to odor perception and recognition. As for other mammalian ORs, few dog OR have been deorphanized, mainly because of the absence of good methodology and the difficulties encountered to express ORs at the cell surface. Within this work, our aim was 1) to deorphanize a large subset of dog OR and 2) to compare the implication of the 2 main pathways, namely the cAMP and inositol 1,4,5-triphosphate (IP3) pathways, in the transduction of the olfactory message. For this, we used 2 independent tests to assess the importance of each of these 2 pathways and analyzed the responses of 47 canine family 6 ORs to a number of aliphatic compounds. We found these ORs globally capable of inducing intracellular calcium elevation through the IP3 pathway as confirmed by the use of specific inhibitors and/or a cAMP increase in response to aldehyde exposure. We showed that the implication of the cAMP or/and IP3 pathway was dependent upon the ligand-receptor combination rather than on one or the other partner. Finally, by exposing OR-expressing cells to the 21 possible pairs of C6-C12 aliphatic aldehydes, we confirmed that some odorant pairs may have an inhibitory or additive effect. Altogether, these results reinforce the notion that odorant receptor subfamilies may constitute functional units and call for a more systematic use of 2 complementary tests interrogating the cAMP and IP3 pathways when deorphanizing ORs

A radiation hybrid map of the European sea bass (Dicentrarchus labrax) based on 1581 markers: Synteny analysis with model fish genomes.

International audienceThe selective breeding of fish for aquaculture purposes requires the understanding of the genetic basis of traits such as growth, behaviour, resistance to pathogens and sex determinism. Access to well-developed genomic resources is a prerequisite to improve the knowledge of these traits. Having this aim in mind, a radiation hybrid (RH) panel of European sea bass (Dicentrarchus labrax) was constructed from splenocytes irradiated at 3000 rad, allowing the construction of a 1581 marker RH map. A total of 1440 gene markers providing ~4400 anchors with the genomes of three-spined stickleback, medaka, pufferfish and zebrafish, helped establish synteny relationships with these model species. The identification of Conserved Segments Ordered (CSO) between sea bass and model species allows the anticipation of the position of any sea bass gene from its location in model genomes. Synteny relationships between sea bass and gilthead seabream were addressed by mapping 37 orthologous markers. The sea bass genetic linkage map was integrated in the RH map through the mapping of 141 microsatellites. We are thus able to present the first complete gene map of sea bass. It will facilitate linkage studies and the identification of candidate genes and Quantitative Trait Loci (QTL). The RH map further positions sea bass as a genetic and evolutionary model of Perciformes and supports their ongoing aquaculture expansion

A Radiation Hybrid map of the genome of Nile tilapia (Oreochromis niloticus)

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