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Nombre de programmes trouvés : 1642
Conférences

le (20m4s)

Dr Liliana D’Alba - Eggshell mineralization in relation to nesting ecology in reptiles

Egg morphology is essential for animal survival, mediating the interactions between embryos and their environment, and a result have evolved into an enormous diversity of forms and functions in modern vertebrates. Reptiles show considerable variation in the degree eggshell calcification, which through evolution shows a tendency to increase. Several hypotheses have been proposed to explain the advantages of intensified mineralization, for example that calcified eggshells increase protection of embryos from mechanical and biological stressors, modulate gas exchange and water physiology or that calcification might be a detoxification mechanism. However, these hypotheses ...
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Conférences

le (17m40s)

Dr Sophie Réhault-Godbert - The eggshell microbiome

Avian eggs possess very efficient and orchestrated systems to protect the embryo during incubation, until hatch. Although the internal components of the egg are assumed to be sterile, the surface of the eggshell is covered by microbes (essentially bacteria) that may contribute to prevent eggshell colonization by pathogenic bacteria, through direct inhibition and/or competitive exclusion. The composition of the eggshell microbiome is a heritage from both maternal microbiota (caeca/faeces) where the egg meets caecal secretions in the cloacal segment during oviposition, and from the nesting environment (contaminated litter/feathers and air environment ...
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Conférences

le (21m31s)

Dr Ian Dunn - The genetics and function of the cuticle, the eggs antimicrobial outer barrier.

Avian eggs have a proteinaceous cuticle covering the outside of the eggshell forming a barrier to the transmission of microorganisms. Although the cuticle is similar to the organic matrix, its secretion is separate from the organic matrix and occurs just prior to oviposition. Using NGS sequence it was possible to investigate genes that might be involved in cuticle deposition, which suggested that an endogenous clock may control events in the uterus, including cuticle deposition. There is considerable variation within breeds of chicken and indeed between species in the quantity of cuticle deposition. ...
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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. ...
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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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