zoo 21 lecture

zoo 21 lecture - Week Four: November 26-30 What are the...

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Week Four: November 26-30 What are the guidance patterns? NCC selectively labeled with antibody to HNK1 - HNK1 – an NCC marker protein, make the orange cells - NCC’s really do only show up in the anterior portion of the sclerotome. - The do not go into the posterior at all
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The Question??? - Are fates of NCC predetermined before beginning of migrations? - Test? – Transplant NCC into embryos of different developmental stages. Use somite number as marker for where the ncc’s come from. - Transplant to Young vs old embryos o young – no migrations of trunk ncc’s have occurred o old – one of two ventrolateral migrations have taken place – the one that goes deepest ventral occurs first The Data - Labeled cells from old donor into young host o labeled cells in both waves – so no deep ventral migration o Why don’t they go through second route? o As the first wave migrates deep ventral, they alter pathway so that next wave can’t follow. So old cells already took care of second pathway and young ncc’s don’t need to, according to the cells. Probably do this by secreting hyalaronidase, etc. - Labeled cells from young donor to old host o labeled cells in 2 nd wave only!!! Le Douarin’s “Chimeras” orthotopic heteroplastic transplants - Results show that cells are multipotential and are differentiated at final resting point. - In all cases, as development continues, fate of a cell becomes more and more channeled until it finally becomes a differentiated cell.
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Mesoderm – trunk divisions - Epimeres - somites o Dermatome – dermis o Myotome – segmented muscles of the trunk o Sclerotome – vertebrae - Mesomere – intermediate mesoderm; contributes to formation of kidney and urogenital structures - Hypomere – lateral plate mesoderm o Somatic (aka somatopleure) – peritoneum, ventral body musculature: the “parietal” mesoderm o Splanchnic – covers internal organs, circulatory system, gonads and spleen Their Positioning
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Formation of the Vertebrate - Oblique migrations of the sclerotome (see overheads) Osteogenesis – bone formation: two methods - Endochondrial ossification – mesenchyme becomes cartilage, then converts to bone, pelvis, vertebrae, axial skeleton; 5 phases – read in book, pages 455-457, mainly know signal transduction pathways involved (ex: BMP role) - Intramembranous ossification – direct conversion of mesencymal tissue to the bone, bones of skull (neural crest cells), pages 420-421 Intermediate Mesoderm - Formation of kidneys and genital system o Linked physiologically, functionally, and anatomically o Reciprocal induction Instructive Permissive o Requires cell contact
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Types of Vertebrate Kidneys - Pronephros – head kidney, most primitive, functional kidney only in anamniotes (embryonic) - Mesonephros – 2 nd kidney to form, posterior to pronephros; functional kidney of adult anamniotes and fetal amniotes - Metanephros – most advanced and most caudal, only forms in adult amniotes Pop Question 13 - Neural crest cells that migrate deep ventral in the region of somites 1-7, innervate the gut
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This note was uploaded on 07/22/2011 for the course BIOL 3156 taught by Professor Lynn,j during the Spring '08 term at LSU.

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zoo 21 lecture - Week Four: November 26-30 What are the...

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