ĭue to the compaction of the sperm genome and the reduction in transcription, significant changes in protein, lipid, and sugar contents are thought to be a result of the uptake of epididymal epithelial secretions. Species specific traits of the stallion sperm head include a characteristic asymmetrical head, a paraxially inserted tail, and a small acrosome relevant to other species. The post-acrosomal lamina covers the caudal nucleus, which contains the highly condensed male genome. In addition, it is theorized that the proteases and hydrolases contained within the acrosome play a role in the penetration of the oocyte cumulus complex, in addition to the zona pellucida. The acrosome covers the anterior portion of the sperm head and contains hydrolytic enzymes which are released in order for the sperm to penetrate an oocyte. The head consists of the acrosome, the post-acrosomal lamina, and the nucleus. The sperm head is an elongated, oval shape that is also relatively flat, with some variation on an individual basis. A spermatozoa consists of three main components: a headpiece, midpiece, and tail which are fully encapsulated by a plasma membrane ( Figure 2). The length of the equine spermatozoa from head to tail is approximately 60 µm. These primary spermatocytes then enter the meiosis phase, where they pass into the adluminal compartment and participate in two meiotic divisions, first becoming haploid secondary spermatocytes and, ultimately, producing haploid spermatids. This period of cell replication is known as spermatocytogenesis and, ultimately, produces preleptotene primary spermatocytes. However, A 1 cells do not express NGN3 and, therefore, will undergo several rounds of mitosis and differentiation while remaining connected by intercellular bridges (A1, A2, A3, B1, B2 stages). A aligned spermatogonia then undergo differentiation into committed A 1-spermatogonia, which also reside in the basal compartment. The basal store of cells begin as single cells (A single) and undergo either a complete mitotic division forming two single daughter cells, or several rounds of incomplete mitosis in order to create paired (A paired) and aligned (A aligned) cell groups connected by intercellular bridges. However, A-spermatogonia exist both to replenish the population of gametic stem cells and differentiate for continuation of spermatogenesis, and, therefore, a subpopulation of A-spermatogonia become committed to differentiation. A non-committed store of A-spermatogonial cells exists at the basal layer and remains undifferentiated due to the expression of the Neurogenin 3 ( NGN3) gene. The process by which mature spermatozoa are generated is a highly regulated process spanning across multiple domains of the testis. In the stallion, it has been shown that seasonal fertility is partially attributed to changes in the number of Sertoli cells in the testis, which is directly correlated with the numbers of spermatozoa ultimately produced. Specifically, Sertoli cells are stimulated by pituitary Follicle Stimulating Hormone (FSH) and secrete a variety of proteins that play a role in germ cell nourishment and development. Within the seminiferous tubules, Sertoli cells span both the basal and adluminal layers, and their role is to host germ cells as they undergo meiosis and differentiation. Leydig cells occupy the interstitial space of the testes between adjacent seminiferous tubules and serve as a key regulator of Sertoli cell function. Leydig cells, which are stimulated by Luteinizing Hormone (LH) to produce sex hormones, including testosterone, are key for regulating spermatogenesis as well as being responsible for the male phenotype. The company has not appointed an interim CFO or given details on its search for his successor.The seminiferous tubule is divided into a basal and an adluminal layer, which is fully surrounded by a basal lamina. His departure is not the result of a disagreement regarding financial disclosures, accounting matters, or any other matter relating to company operations, according to a U.S Securities and Exchange Commission filing. Williams, a 28-year veteran of the company, will leave the company on July 1. Tanger Factory Outlet Centers notified James Williams he would no longer be the company’s CFO, treasurer, and executive vice president, or hold any of his roles across company subsidiaries. James Williams | Tanger Factory Outlet Centers He previously worked at The Kraft Heinz Company as head of global internal audit and at The Hillshire Brands Company as senior vice president, corporate controller, and chief accounting officer. He was most recently executive vice president and CFO. Kelley joins the juice manufacturer from Treehouse Foods, where he has worked for the last six years.
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