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Интеллектуальная Система Тематического Исследования НАукометрических данных |
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Fine morphology of the jaw apparatus in one species of Fissurelidae (Puncturella noachina)статья
- Авторы: Vortsepneva Elena, Ivanov Dmitry, Purschke Günter, Tzetlin Alexander
- Журнал: Journal of Morphology
- Том: 275
- Номер: 7
- Год издания: 2014
- Издательство: John Wiley & Sons Inc.
- Местоположение издательства: United States
- Первая страница: 775
- Последняя страница: 787
- DOI: 10.1002/jmor.20259
- Аннотация: Jaws of various kinds occur in virtually all groups of Mollusca, except for two taxa: Polyplacophora and Bivalvia. Molluscan jaws are formed by the buccal epithelium and constitute a single plate, a paired formation or a serial structure. Despite the presence of rather complete information about the general morphology of jaws in various gastropod groups, there are only few works on both the fine structure of jaws and peculiarities of formation and growth of the jaws. Buccal ectodermal structures in gastropods are rather different. They can be non-renewable or having final growth, like the hooks in Clione. In this case, they are formed by a single cell. Conversely, they can be renewable during the entire life span and in this case they are formed by a set of cells, like the jaws and the radula. The permanent renewal occurs due to secretory activity of gnatho- and odontoblasts. Such diversity in the structure and formation indicates a considerable functional plasticity of the ectodermal epithelium.The fine structure of the jaws was studied in the gastropod Puncturella noachina. The jaw is situated in the buccal cavity and consists of paired elongated cuticular plates. On the anterior edge of each cuticular plate there are numerous longitudinally-oriented rodlets disposed over the entire jaw surface and immersed into a cuticular matrix. The jaw can be divided into four zones situated successively towards the anterior edge: (1) posteriormost area: the zone of formation of thick cuticle covering the entire jaw and forming the electron-dense outer layer of the plate; (2) the zone of rodlet formation; (3) the zone where fully formed rodlets become arranged longitudinally and in several layers; and (4) the anterior zone: free scraping edge of the plate, or the erosion zone. In the general pattern of jaw formation, Puncturella noachina resembles the previously studied Testudinalia tessulata (Patellogastropoda). The basis of the jaw is a cuticular plate formed by the activity of strongly developed microvillar apparatus of the gnathoepithelium. However, the mechanism of renewal of the jaw anterior part in P. noachina is much more complex since its scraping edge consists not just of a thick cuticular matrix rather than of a system of denticles being the projecting endings of rodlets.
- Добавил в систему: Ворцепнева Елена Владимировна