Morphological Aspects of Gonadal Morphogenesis inBufo bufo (Amphibia anura): Bidder's Organ Differentiation
| Autor: | Davide Dalpiaz, Rosanna Falconi, Francesco Zaccanti |
|---|---|
| Přispěvatelé: | Falconi R., Dalpiaz D., Zaccanti F. |
| Rok vydání: | 2007 |
| Předmět: |
GONADAL MORPHOGENESIS
Male Sex Differentiation Time Factors Histology Somatic cell media_common.quotation_subject Morphogenesis Cell Count Biology Basement Membrane Bufo bufo Oogonia medicine Animals Humans Meiotic Prophase I Metamorphosis Gonads Ecology Evolution Behavior and Systematics Cell Size media_common Bidder's organ ASYNCHRONOUS GERM CELLS NEST BIDDER’S ORGAN DIFFERENTIATION Stem Cells Ovary Cell Differentiation Anatomy Meiosis Germ Cells medicine.anatomical_structure Larva Oocytes Ultrastructure Female Basal lamina Stem cell Germ cell Biotechnology |
| Zdroj: | The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology. 290:801-813 |
| ISSN: | 1932-8494 1932-8486 |
| Popis: | We have described the architecture of Bidder's organ, defined its compartmented structure, and affirmed the presence of basal laminae. We did not find morphological differences between sexes in Bidder's organ. All specimens initially developed gonads with a peripheral fertile layer surrounding a thin primary cavity. The first oogenetic wave was observed early, showing all phases of meiosis, including leptotene, zygotene, and pachytene, which had been previously thought to be lacking. The peculiar presence of an asynchronous germ cell nest was discussed. Diplotene oocytes issued from the peripheral layer and migrated inside the primary cavity. They were surrounded by a single layer of follicular cells, which originated from the peripheral layer somatic cells and were delimited by a basal lamina. There were few medulla or central layer cells. At the end of metamorphosis, while the oocytes of the first oogenetic wave came into close contact with blood vessels, a second oogenetic wave took place just as the first, except for the presence of synchronous germ cell nests. The central layer was not visible and we did not observe the formation of an ovarian pocket. Stocks of stem germ cells remained in the peripheral layer during both the first and second oogenetic waves. The asymmetric model, in which there is a tendency toward a primary female differentiation, was confirmed. The female differentiation becomes stable in the Bidder's organ because of the absence of further interaction between germ and medullary somatic cells, which would have led toward a male differentiation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text