Topic
Seminatrix
About: Seminatrix is a research topic. Over the lifetime, 18 publications have been published within this topic receiving 369 citations.
Papers
TL;DR: Oviducal sperm storage in the viviparous colubrid snake Seminatrix pygaea was studied by light and electron microscopy and sperm were found in the lumen and glands of the posterior uterus and anterior vagina, indicating a recent mating.
Abstract: Oviducal sperm storage in the viviparous (lecithotrophic) colu- brid snake Seminatrix pygaea was studied by light and electron microscopy. Out of 17 adult snakes examined from May-October, sperm were found in the oviducts of only two specimens. In a preovulatory female sacrificed 14 May, sperm were found in the oviducal lumen and sperm storage tubules (SSTs) of the posterior infundibulum. In a nonvitellogenic female sacrificed 9 June, sperm were found in the lumen and glands of the posterior uterus and anterior vagina, indicating a recent mating. The glands in the posterior infundibulum and vagina were simple or compound tubular, whereas glands in the uterus always were simple tubular. The epithelium of the sperm storage glands was not modified from that lining the rest of the oviduct. The cuboidal or columnar epithelium consisted of alternating ciliated and secre- tory areas. The secretory product released into the lumen by a merocrine process contained mucoprotein. Lipid droplets also were numerous in the epithelium. Portions of sperm sometimes were embedded in the apical cyto- plasm or in secretory material. A carrier matrix containing a mucoid sub- stance, desquamated epithelium, lipids, membranous structures, and possi- bly phagocytes was found around sperm in the posterior uterus. J. Morphol. Sperm storage tubules (SSTs) probably occur in the oviducts of all female snakes (Fox and Dessauer, '62; Devine, '84), and sperm storage in the female oviduct also has been reported in the other extant reptile groups, except Rhynocephalia (for reviews see Howarth, '74; Saint-Girons, '75, '82; Fox, '77; Devine, '84; Gist and Jones, '87; Birk- head and Moller, '93; Blackburn, '98). The reptilian oviduct basically consists of an an- terior infundibulum, into which eggs are ovulated from the ovary; a middle uterus where eggs are held until oviposition or em- bryos develop until parturition; and a poste- rior vagina that opens into the cloaca (Gist and Jones, '87; Blackburn, '98). In addition, turtles and crocodilians have a ''tubal'' re- gion between the infundibulum and uterus where albumen-secreting glands, absent in snakes and lizards, are found. The site of sperm storage in the oviduct of crocodilians is unknown (Davenport, '95), but in turtles SSTs occur in the tubal region (Gist and Jones, '87). In lizards and snakes, SSTs oc- cur at the junction of the infundibulum and uterus, and sperm also may be stored in furrows or glands in the vaginal mucosa (Fox, '56; Cuellar, '66; Halpert et al., '82). Detailed anatomical studies on the histol- ogy and cytology of the sperm storage re- gions of the oviduct in reptiles are few. In snakes, studies at the light microscopy level exist (chronologically) for Thamnophis sirta- lis (Rahn, '40; Fox, '56; Hoffman and Wim- satt, '72; Halpert et al., '82), Crotalus viridis
68 citations
TL;DR: This article provides the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea, and shows that synthesis of secretory product is initiated with the onset of spermatogenic activity in the spring and culminates with completion of spermiation in the fall.
Abstract: In mature male snakes and lizards, a distal portion of the nephron is hypertrophied in relation to its appearance in females and immature males. This sexual segment of the male kidney apparently provides seminal fluid that is mixed with sperm and released into the female cloaca during copulation. In this article, we provide the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea. Previous workers have indicated that the sexual segment is secretory only when the testes are spermatogenically active. The sexual segment of the kidney in S. pygaea does not go through an extended period of inactivity but does show a cycle of synthesis and secretion that can be related to the spermatogenic cycle and mating activity. We show that synthesis of secretory product is initiated with the onset of spermatogenic activity in the spring and culminates with completion of spermiation in the fall. Secretion of the product, however, occurs in a premating period in March when the testes are inactive. Secretion during this premating period is probably necessary to provide time for the passage of the products down the ureter in order to mix with sperm during mating later in spring.
59 citations
TL;DR: The distal end of the ductus deferens of Seminatrix pygaea (Cope) differs from more proximal portions of the tube by possessing a highly fluctuated epithelium, and the presence of numerous small apical vesicles indicates a role in fluid absorption.
Abstract: The distal end of the ductus deferens of Seminatrix pygaea (Cope) differs from more proximal por- tions of the tube by possessing a highly fluctuated epithe- lium. Similar morphology has been reported in this area in one lizard and some mammals and the region has been designated in these taxa as the ampulla ductus deferentis. In this study, light and transmission electron microscopy were used to study the posterior ductus deferens in S. pygaea and compare the histology in this region to more proximal regions of the duct and to descriptions of the ampulla of other species. Seminatrix pygaea stores sperm throughout the ductus deferens during the entire year. The epithelium of the ductus deferens is not secretory, but the presence of numerous small apical vesicles indicates a role in fluid absorption. In addition to the highly folded epithelium, clusters of sperm nuclei are more intimately associated with the apical ampullary epithelium than elsewhere in the ductus deferens. No evidence of phago- cytosis of sperm was found. In contrast, the ampulla of mammals and presumably the lizard Calotes versicolor is glandular and phagocytic. The common character shared by the squamates and mammals with specializations in this area is the folded epithelium, and whether this is due to shared ancestry with amniotes or is homoplastic is unresolved. J. Morphol. 262:714 -730, 2004. © 2004 Wiley-Liss, Inc.
42 citations
TL;DR: The ultrastructural study on the annual oviducal cycle in a snake was studied in 21 females of the viviparous natricine snake Seminatrix pygaea, finding the anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition.
Abstract: This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998-1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, and the vagina. The epithelium is simple throughout the oviduct and invaginations of the lining form tubular glands in all regions except the anterior infundibulum and the posterior vagina. The tubular glands are not alveolar, as reported in some other snakes, and simply represent a continuation of the oviducal lining with no additional specializations. The anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition. In these regions, the epithelium is irregular, varying from squamous to columnar, and cells with elongate cilia alternate with secretory cells. The secretory product of the infundibulum consists largely of lipids, whereas a glycoprotein predominates in the vagina; however, both products are found in these regions and elsewhere in the oviduct. In the SST area and the anterior vagina, tubular glands are compound as well as simple. The epithelium of the SST is most active after mating, and glycoprotein vacuoles and lipid droplets are equally abundant. When present, sperm form tangled masses in the oviducal lumen and glands of the SST area. The glands of the uterus are always simple. During sperm migration, a carrier matrix composed of sloughed epithelial cells, a glycoprotein colloid, lipids, and membranous structures surround sperm in the posterior uterus. During gravidity, tubular glands, cilia, and secretory products diminish with increasing development of the fetus, and numerous capillaries abut the basal lamina of the attenuated epithelial lining of the uterus.
42 citations
TL;DR: The characteristics of the anterior testicular ducts of the North American natricine snake Seminatrix pygaea are concordant with those of other amniotes, and the traditional names used for snakes are changed to conform with those used for other sauropsids and mammals.
Abstract: In this study, the anterior testicular ducts of the North American natricine snake Seminatrix pygaea are described using light and electron micros- copy. From the seminiferous tubules, the rete testis passes into the epididymal sheath, a structure along the medial border of the testis heavily invested with colla- gen fibers. The rete testis consists of simple, nonciliated cuboidal epithelium (principal cells). The intratesticular ducts of the rete testis are narrow (50-70 lm) at their junction with the seminiferous tubules, widen (80-100 lm) as they extend extratesticularly, and divide into smaller branches as they anastomose with the next tubules, the ductuli efferentes. The ductuli efferentes are lined by simple cuboidal epithelium but possess non- ciliated principal cells as well as ciliated cells. These are the only ducts in the male reproductive system with cili- ated cells. The ductuli efferentes are narrow (25-45 lm), divide into numerous branches, and are highly convo- luted. The ductus epididymis is the largest duct in diam- eter (240-330 lm), and the diameter widens and the epithelium thins posteriorly. The ductus epididymis is lined by nonciliated, columnar principal cells and basal cells. No regional differences in the ductus epididymis are apparent. Ultrastructural evidence suggests that all of the nonciliated principal cells in each of the anterior testicular ducts function in both absorption and secre- tion. Absorption occurs via small endocytic vesicles, some of which appear coated. Secretion is by a constitu- tive pathway in which small vesicles and a flocculent material are released via a merocrine process or through the formation of apocrine blebs. The secretory product is a glycoprotein. Overall, the characteristics of the ante- rior testicular ducts of this snake are concordant with those of other amniotes, and the traditional names used for snakes are changed to conform with those used for other sauropsids and mammals. J. Morphol. 271:104- 115, 2010. 2009 Wiley-Liss, Inc.
32 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2010 | 1 |
| 2009 | 1 |
| 2008 | 1 |
| 2005 | 3 |
| 2004 | 1 |
| 2002 | 1 |