Spermiogenesis and spermiation in a monotreme mammal, the platypus, Ornithorhynchus anatinus
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چکیده
منابع مشابه
Characterization of the Mel1c melatoninergic receptor in platypus (Ornithorhynchus anatinus)
Melatonin is a neurohormone produced in both animals and plants. It binds at least three G-protein-coupled receptors: MT1 and MT2, and Mel1cGPR. Mammalian GPR50 evolved from the reptilian/avian Mel1c and lost its capacity to bind melatonin in all the therian mammal species that have been tested. In order to determine if binding is lost in the oldest surviving mammalian lineage of monotremes we ...
متن کاملEnergetics of terrestrial locomotion of the platypus Ornithorhynchus anatinus.
The platypus Ornithorhynchus anatinus Shaw displays specializations in its limb structure for swimming that could negatively affect its terrestrial locomotion. Platypuses walked on a treadmill at speeds of 0.19-1.08 m x s(-1). Video recordings were used for gait analysis, and the metabolic rate of terrestrial locomotion was studied by measuring oxygen consumption. Platypuses used walking gaits ...
متن کاملHistological and immunohistological investigation of lymphoid tissue in the platypus (Ornithorhynchus anatinus).
The gross and histological appearance and the distribution of T and B lymphocytes and plasma cells are described for lymphoid tissues obtained from 15 platypuses. The spleen was bilobed and surrounded by a thick capsule of collagen, elastic fibres and little smooth muscle. White pulp was prominent and included germinal centres and periarterial lymphoid sheaths. Red pulp contained haematopoietic...
متن کاملOrnithorhynchus anatinus (platypus) links the evolution of immunoglobulin genes in eutherian mammals and nonmammalian tetrapods.
The evolutionary origins of mammalian immunoglobulin H chain isotypes (IgM, IgD, IgG, IgE, and IgA) are still incompletely understood as these isotypes differ considerably in structure and number from their counterparts in nonmammalian tetrapods. We report in this study that the platypus (Ornithorhynchus anatinus) Ig H chain constant region gene locus contains eight Ig encoding genes, which are...
متن کاملDiving behaviour, dive cycles and aerobic dive limit in the platypus Ornithorhynchus anatinus.
We investigated the diving behaviour, the time allocation of the dive cycle and the behavioural aerobic dive limit (ADL) of platypuses (Ornithorhynchus anatinus) living at a sub-alpine Tasmanian lake. Individual platypuses were equipped with combined data logger-transmitter packages measuring dive depth. Mean dive duration was 31.3 s with 72% of all dives lasting between 18 and 40 s. Mean surfa...
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ژورنال
عنوان ژورنال: Journal of Anatomy
سال: 2000
ISSN: 0021-8782,1469-7580
DOI: 10.1046/j.1469-7580.2000.19620217.x