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Nombre de programmes trouvés : 1785
Conférences

le (18m10s)

Prof. Maxwell Hincke - The chroriallantoic membrane: insight from proteomics.

In oviparous animals such as birds, embryonic development occurs in the egg; after oviposition, there is no further possibility of material exchange from the hen to fulfill the physiological needs of the embryo. In such a context, the egg must contain all resources required for survival and proper development of a living organism. During embryonic development, the chorioallantoic membrane (CAM) is a placenta-like structure which is the nexus for many different physiological and metabolic processes including acid-base balance, respiration, and calcium solubilization from the eggshell that is re-allocated for bone and tissue ...
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Conférences

le (20m50s)

Dr Nicolas Guyot - Phylogenetic and structural evolution of egg antimicrobial proteins and peptides

The avian egg is designed to support the autonomous development of the chick embryo in the outside environment. It initially contains all the nutrients required for embryonic growth and provides efficient physical and immune protections primarily via the calcified eggshell and the numerous antimicrobial proteins and peptides. The antimicrobial content of eggs has been shaped during evolution to cope with the microbial pressure and potential contaminations. These antimicrobials are present within all parts of the egg, although they are mostly abundant and active in the egg white and in the perivitelline layer. ...
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Conférences

le (20m39s)

Dr Claudine Blin - The innate immune function and diversity of osteoclasts

Osteoclasts are the cells responsible for bone resorption in steady state and bone destruction in chronic inflammatory diseases and osteoporosis.  Up to recently, they have been considered only as a single population of bone-resorbing cells whose differentiation and activity are increasing in pathologies associated with bone destruction. However, recent data demonstrated that besides bone resorption, osteoclasts are innate immune cells. In particular, they present antigens and activate T cell responses towards tolerance in steady state. Moreover, they are also able to stimulate inflammatory T cells in the context of chronic inflammation. Using ...
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Conférences

le (20m46s)

Dr Natalie Reznikov - Application of deep learning for segmentation of 3D images in biomineralization

Modern 3D imaging methods in biomineralization – such as X-ray tomography and dual-beam electron tomography – produce datasets that are rich in fine detail and enormous in size, often containing inevitable artifacts.  Rendering segmentations of such datasets is a daunting task.  The recent introduction of artificial neural network-based deep learning into bioimaging has made 3D segmentation reliable, accurate and fast.  A highlight of convolutional neural networks (CNNs) is that artificial "neurons" are interlinked hierarchically, similarly to how feature-forming patterns of an image are related.  Accordingly, when a raw image is presented to ...
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Conférences

le (20m6s)

Dr Frédéric Marin - Mollusk shell matrices: unexpected functions in biomineralization

To construct their skeletons, all metazoans secrete a complex array of macromolecules that are supposed to display key-functions in biomineralization, such as crystal nucleation and crystal growth orientation. These macromolecules - generally less than 1% of the skeletal weight - are occluded during skeletal growth and can be retrieved and analyzed by dissolving the mineral phase. They comprise proteins, glycoproteins, peptides, polysaccharides, and sometimes, lipids, pigments and metabolites. They constitute collectively the 'calcifying matrix', from which proteins and glycoproteins are the most studied.  In the last decade, the coupling of high-throughput screening ...
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Conférences

le (19m35s)

Dr Sophie Berland - Probing the mechanical properties and biochemical defence offered by shell matrix proteins in bivalves

Calcium carbonate is paired up with shell matrix proteins in the suited organo-mineral outer shell in molluscs. Advanced knowledge in the shell proteome is achieved with the development of proteomics providing insights in the biological control of biomineralization at the shell side. Four bivalve species of distant kinship were subjected to proteomics for sequence and function pattern analysis of their retrieved shell matrix proteins. Domains ruling for calcification mechanisms, e.g. carbonic anhydrase, chitin binding and tyrosinase remained common in all the species signing sustained calcifying control proteins. Other shell proteins were fitted ...
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Conférences

le (19m2s)

Dr Christine Paillard - The Brown Ring disease in clams, a double-edged defense mechanism for shell disease recovery!

Brown Ring disease is caused by Vibrio tapetis, which, by adhering to newly secreted shell matrices, interferes with the biomineralization process. Colonization and alteration of the matrices induce the deposit of conchiolin on the inner surface of the valves, forming a characteristic brown deposit instead of contributing to shell growth. This defense mechanism consists firstly in coating the bacteria within the organic layers of melanized matrices, and secondly in covering the brown deposit with shell layers to achieve complete healing of the shell. This defense phenotype varies greatly depending on, (1) the ...
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Conférences

le (22m38s)

Dr Robbie Rae - Biological armour used to kill parasites

The co-evolution of parasites and hosts has shaped the immune system. One such ‘arms race’ is between parasitic nematodes and their molluscan hosts. One such species (Phasmarhabditis hermaphrodita) can infect and kill several gastropod species and has been formulated into a biological control agent (Nemaslug®) for farmers and gardeners. In order to defend themselves from P. hermaphrodita infection we have recently found that several snail species encapsulate and kill nematodes by producing unknown cells which fuse them to the inner part of the shell. This is a rapid process occurring over 48 ...
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