About this Research Topic
Gamete physiology is part of the fertilization process. In mammals, most of the knowledge of these processes has been acquired from in vitro, and later from in vivo research on the murine and human models. However, there are several differences that distinguish domestic and wild animals from the former biological models. As examples, the stallion sperm oxidative metabolism differs from human sperm: on the contrary to model animal species such as the mouse, where hyperactivation can be elicited by cyclic adenosine monophosphate (cAMP) analogues leading to intracellular alkalinisation, hyperpolarization and extracellular calcium entry through CatSper channel, physiologically relevant conditions have not been established in stallion spermatozoa. Moreover, there is a lack of criteria for the definition of hyperactivated motility and there are no reports that deeply study signaling pathways leading to capacitation in this specie, as there isn't much information in ram sperm, either.
This Research Topic collection also aims to fill the information gap related to the effect of male and female microenvironments over sperm physiology. In this direction, as in vitro capacitation media mimic physiological fluids and most knowledge comes from murine and human models that only need ClNa, HCO3, BSA, Calcium and energy sources, bovine, stallion and ram sperm capacitation inductors have not been yet well defined. On the other side, proteomic studies demonstrated that seminal plasma composition in camelids is distinct from other mammals. Given the discovery that seminal plasma molecules regulate sperm physiology, the understanding of the molecular mechanisms in this species requires particular studies.
From the point of view of the female gamete, there are also unique features that require deeper understanding. In-vitro maturation from preantral follicles, followed by fertilization and birth of offspring, has formerly been successful in the mouse where physiological processes are accelerated. In other species with longer cycles, media conditions must stabilize the cycle of genomic activation. Lipid β-oxidation is required for the resumption of meiosis and nuclear maturation. However, physiological studies are interesting in light of mouse comparatively low levels of intracellular lipid stores compared with bovine and porcine oocytes. Additionally, most domestic and wild animal females have estrous cycles linked to the photoperiod, differently from mice and human.
This Research Topic aims to gather research on distinct molecular and cellular physiological processes in both spermatozoa and oocyte of non-murine or human models, focused on understanding reproductive competence in domestic and wild animals. This knowledge will contribute not only with animal production biotechnology, but also with the conservation of animal biodiversity, especially of wild animals.
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