Abnormal morphogenesis of skin and feathers in the chicken embryo induced by the l-proline analog, l-azetidine-2-carboxylic acid: a light microscopical, ultrastructural (sem and tem) and chemical analysis, 1980

Miller, Andrea L.

1980-1989

Collagen is known to play a vital role in several developing systems which depend on epithelio-mesenchymal interactions for their normal morphogenesis. The development of embryonic chick skin has been found to be dependent on interactions between mesoderm (dermis) and ectoderm (epidermis) and collagen has been implicated in the formation of feather germs and feather patterns. Since collagen is the most abundant protein found in connective tissue and the major structural constituent of skin, the problem of whether normal skin morphogenesis is dependent on normal collagen biosynthesis is the subject of concern. The use of several proline analogs has provided a useful tool in exploring the morphogenesis of several differentiating collagen-dependent systems. In vitro studies have shown that the structural proline analog, L-azetidine-2-carboxylic (LACA), interferes with the normal biosynthesis of collagen molecules. The procollagen polypeptide chains containing the analog are underhydroxylated and, therefore, do not fold into the normal triple helical conformation; this causes a delay in the secretion of the molecule into the extracellular matrix. The purpose of this investigation was, therefore, to study the abnormal morphogenetic and biochemical changes that occurred in chick embryo skin due to the administration of the proline analog, LACA, and to determine if these changes were due possibly to an interruption of collagenogenesis. Fertile eggs of the White Leghorn Variety chicken were injected with 0.6 cc of 1 mg/ml of solution of LACA through the air sacs at pre-incubation, 24 hr and at 48 hr of incubation. Single injections of 0.9 cc of 1 mg/ml of LACA solution were also given at pre-incubation, 16-18 hr, 24 hr, or 48 hr of incubation. The embryos were removed from their shells and analyzed for suppression and/or inhibition of feathers. The time at which the single injections were made proved to be critical. The highest percentage of feather suppression (30%) occurred in embryos that were injected at 16-18 hr of incubation. However, triple-injections caused an even greater percentage of feather suppressions and/or inhibitions (35%). This high percentage of feather suppressions was observed in embryos at days 11-12 as opposed to earlier or later days.

text

application/pdf

1980-08-01

dissertation

Doctor of Philosophy (PhD)

Atlanta University

Department of Biology

Hunter Jr., Roy

Clark Atlanta University

Georgia--Atlanta

http://hdl.handle.net/20.500.12322/cau.td:1980_miller_andrea_l