Intraovarian sperm storage in Helicolenus dactylopterus dactylopterus fertilitzation, crypt formation and maintenance of stored sperm

The females of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (DelaRoche, 1809), store sperm within their ovaries for periods of up to 10 months. Twenty six females with standard lengths between 152 and 257 mm and six males with standard lengths between 253 and 209 mm were caught storage crypts with stored spermatozoa and to describe their evolution over the year. After internal fertilization and once sperm reaches the ovary, a crypt forms probably by an epithelial inclusion at the base of the lamellae of one or several spermatozoa groups that are floating freely in the interlamellar space of the ovarian lumen. Stored spermatozoa have a large cytoplasm bag surrounding their heads. This bag could serve as a nutritive reservoir during the long storage period. Many desmosonal and tight junctions between the crypt cells ensure tha male sex cells are protected against the female immune system

Spermiogenesis particularities of a sperm storage species: Helicolenus dactylopterus (Teleostei: Scorpaenidae)

A study of the spermiogenesis and spermatozoa of Helicolenus dactylopterus was conducted. Females of this species have the capacity to store sperm within their ovaries, and male gametes have a considerable cytoplasmic mass surrounding their heads to survive the long period of intraovarian sperm storage. Our observations show that early spermatids are round-shaped cells and have a spherical nucleus with diffuse chromatin. The nuclear volume decreases as a result of progressive chromatin condensation during spermiogenesis, causing the nucleus to take on a U-shape. Flagellar insertion is not central to the nucleus but consistently occurs at an oblique angle towards one side of it. The flagellum is inserted into the nuclear fossa, without subsequent nuclear rotation. In mature spermatozoa, the flagellum is adjacent to the nucleus. A comparison of the spermatozoa in the testicular lobules and those in the intraovarian storage structures suggests that the increase in volume of the cytoplasmic mass may occur in the posterior region of the testis, in the testicular duct. Spermatozoa enter the ovary in groups that reach the ovarian lumen and are surrounded by the ovarian epithelium for storage in sperm storage crypts

Histochemical study of the oviducal gland and analysis of the sperm storage tubules of Mustelus schmitti Springer, 1939 (Chondrichthyes, Triakidae)

Abstract: The paired oviducal glands of immature and mature females of Mustelus schmitti were examined macro and microscopically. Findings indicate that these glands possessed the same zonation as in most chondrichthyans from anterior to posterior: club, papillary, baffle and terminal zones. The whole gland is composed by simple tubular glands that connect with transverse grooves all along the organ. The club zone presents a typical indian club shape with a simple columnar and ciliated epithelium including secretory cells PAS (+) and AB (+). The papillary zone is characterized by lamella forming small and long cones in numbers of three. The epithelium of this zone contains ciliated cells with apical nuclei and secretory cells with basal nuclei that stain AB (+)The baffle zone consists of apically flattened lamellae alternating with spinnerets which are small projections disposed by both sides of the plateau. This whole structure is present in number of 8 or 9 units. A simple columnar ciliated epithelium covers the plateau and spinnerets and no AB or PAS staining is observed. The epithelium of the terminal zone is PAS (-) and AB (+), and elongated tubules, that run adjacent to the baffle zone are the site where groups of spermatozoa are clearly observed in the lumen. The epithelium of the sperm storage tubules do not stain with any of the dyes tested. Sperm was also observed in the baffle zone, presumably in its way to the fecundation in the oviduct because it displays no aggregation pattern and was between the folds of the epithelium. By scanning electron microscopy sperm was observed in the club and baffle zones in a gland which belonged to a pregnant female.

Intraovarian sperm storage in Helicolenus dactylopterus dactylopterus fertilitzation, crypt formation and maintenance of stored sperm

The females of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (DelaRoche, 1809), store sperm within their ovaries for periods of up to 10 months. Twenty six females with standard lengths between 152 and 257 mm and six males with standard lengths between 253 and 209 mm were caught storage crypts with stored spermatozoa and to describe their evolution over the year. After internal fertilization and once sperm reaches the ovary, a crypt forms probably by an epithelial inclusion at the base of the lamellae of one or several spermatozoa groups that are floating freely in the interlamellar space of the ovarian lumen. Stored spermatozoa have a large cytoplasm bag surrounding their heads. This bag could serve as a nutritive reservoir during the long storage period. Many desmosonal and tight junctions between the crypt cells ensure tha male sex cells are protected against the female immune system

Spermiogenesis particularities of a sperm storage species: Helicolenus dactylopterus (Teleostei: Scorpaenidae)

A study of the spermiogenesis and spermatozoa of Helicolenus dactylopterus was conducted. Females of this species have the capacity to store sperm within their ovaries, and male gametes have a considerable cytoplasmic mass surrounding their heads to survive the long period of intraovarian sperm storage. Our observations show that early spermatids are round-shaped cells and have a spherical nucleus with diffuse chromatin. The nuclear volume decreases as a result of progressive chromatin condensation during spermiogenesis, causing the nucleus to take on a U-shape. Flagellar insertion is not central to the nucleus but consistently occurs at an oblique angle towards one side of it. The flagellum is inserted into the nuclear fossa, without subsequent nuclear rotation. In mature spermatozoa, the flagellum is adjacent to the nucleus. A comparison of the spermatozoa in the testicular lobules and those in the intraovarian storage structures suggests that the increase in volume of the cytoplasmic mass may occur in the posterior region of the testis, in the testicular duct. Spermatozoa enter the ovary in groups that reach the ovarian lumen and are surrounded by the ovarian epithelium for storage in sperm storage crypts

Sperm storage structures in the ovary of Helicolenus dactylopterus dactylopterus (Teleostei : Scorpaenidae): An ultrastructural study

The ultrastructure of ovarian sperm storage of Helicolenus dactylopterus dactylopterus is described, before and after the spawning period. The spermatozoa remain inside cryptal structures that are situated in the interlamellar gaps and are connected to the ovarian lumen by a duct. This complex forms a highly specialised structure. During the long storage period, crypts are richly vascularised. Their surrounding simple epithelia have intercellular junctions that may serve to protect the spermatozoa from the female immune system. At the moment during which insemination of mature oocytes occurs, the sperm may be expelled from cryptal structures by means of a spasmodic contraction. During the post spawning period, residual spermatozoa that remain in the crypts are eliminated by cryptal phagocytes. At the end of the process the crypts contain only an amorphous material.

Sperm characteristics of Steindachneridion parahybae (Steindachner, 1877) throughout 112h of storage at four temperatures

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Testis size, sperm characteristics and testosterone concentrations in four species of shrews (Mammalia, Soricidae).

The aim of this study was to establish and compare the sperm characteristics in four shrew species in the context of the sperm competition hypothesis. As expected, the large relative testis size in promiscuous species was associated with a high number of cauda epididymal spermatozoa and a high concentration of circulating testosterone. In addition, in Sorex and Neomys, species with high intensity of sperm competition, the spermatozoa stored in cauda epididymis were characterized by high percentage of progressive motility whereas in Crocidura and Suncus, the cauda epididymal spermatozoa were motile but with very low percentage of progressive motility. This capability is achieved only following the passage through the vas gland, a specialized region for sperm storage located along the vas deferens in these shrew species. The hypothesis that sperm competition is positively correlated with spermatozoa length could not be confirmed. In Crocidura and Suncus, the total sperm length is increased by the large sperm head due to a big acrosome. This trait, specific to the subfamily Crocidurinae, may results from a selective pressure independent of the context of sperm competition, related to a specific, but as yet unclear role, for the acrosome during the fertilization.

Glutamate-induced obesity leads to decreased sperm reserves and acceleration of transit time in the epididymis of adult male rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Functional morphology of the reproductive system and sperm transfer in Stenopus hispidus (Crustacea: Decapoda: Stenopodidea), and their relation to the mating system

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Glutamate-induced obesity leads to decreased sperm reserves and acceleration of transit time in the epididymis of adult male rats

Background: Given the established fact that obesity interferes with male reproductive functions, the present study aimed to evaluate sperm production in the testis and storage in the epididymis in a glutamate-induced model of obesity. Methods: Male rats were treated neonatally with monosodium glutamate (MSG) at doses of 4 mg/kg subcutaneously, or with saline solution (control group), on postnatal days 2, 4, 6, 8 and 10. On day 120, obesity was confirmed by the Lee index in all MSG-treated rats. After this, all animals from the two experimental groups were anesthetized and killed to evaluate body and reproductive organ weights, sperm parameters, plasma hormone levels (FSH, LH and testosterone), testicular and epididymal histo-morphometry and histopathology. Results: Significant reductions in absolute and relative weights of testis, epididymis, prostate and seminal vesicle were noted in MSG-treated animals. In these same animals plasma testosterone and follicle-stimulating hormone (FSH) concentrations were decreased, as well as sperm counts in the testis and epididymis and seminiferous epithelium height and tubular diameter. The sperm transit time was accelerated in obese rats. However, the number of Sertoli cells per seminiferous tubule and stereological findings on the epididymis were not markedly changed by obesity. Conclusions: Neonatal MSG-administered model of obesity lowers sperm production and leads to a reduction in sperm storage in the epididymis of adult male rats. The acceleration of sperm transit time can have implications for the sperm quality of these rats.

Seasonal variation of peptidase activities in the reproductive tract of Crotalus durissus terrificus

Seasonal quantitative patterns of acid (APA), basic (APB), puromycin-sensitive (APN-PS) and puromycin-insensitive neutral (APN-PI), cystyl (CAP), dipeptidyl IV (DPPIV), type-1 pyroglutamyl (PAP-I) and prolylimino (PIP) aminopeptidases and prolyl oligopeptidase (POP) activities in soluble (SF) and solubilized membrane-bound (MF) fractions from ductus deferens, vagina and uterus were studied to evaluate their relationships with the reproductive cycle and the extensive long-term spermatozoa storage (LTSS) of the Neotropical rattlesnake Crotalus durissus terrificus. APB, PIP and POP were detected only in SF, while other peptidases were detected in SF and MF. APB, APN-PI and APN-PS were predominant in most tissues in all seasons. Peptidase activities had a common pattern of increment during the dry season (winter/autumn), which coincides with the mating period (autumn) and LTSS in the female (winter), as well as the reduction of spermatozoa motility and maintenance of fertilization capacity of spermatozoa. The high CAP activity in the soluble fraction of the vagina during winter, compared to summer (time of parturition) and spring, coincides with the relaxation of this tissue. In the soluble fraction, the low PAP-1 activity of the ductus deferens coincided with its high activity in the vagina during the winter; and the inverse occurred in summer, which is consistent with the physiological process of preserving spermatozoon viability. In conclusion, the studied peptidase activities had seasonal and tissue-specific characteristics, which suggest a relevant role in the reproductive physiology of C. d. terrificus. (C) 2008 Elsevier Inc. All rights reserved.

Macroscopic and microscopic anatomy of the oviduct in the sexually mature rhea (Rhea americana)

The morphological characteristics of the oviduct of 12 sexually mature rheas (Rhea americana) were studied. Only the left oviduct is developed as a long tube with a length of 122 +/- 23.1 cm, and is subdivided into infundibulum (15.2 +/- 4.0 cm), magnum (63.3 +/- 9.4 cm), isthmus (5.6 +/- 3.1 cm), uterus (16.0 +/- 4.2 cm) and vagina (11.5 +/- 1.4 cm). The mucous membrane of the oviduct, as a whole, possesses luminal folds covered by ciliated columnar epithelium with secretory cells. The infundibulum part presents a cranial opening with thin and long fimbriae with few tubular glands in caudal tubular portion. In the magnum, the largest portion of the oviduct, the folds are thicker and are filled with tubular glands. The isthmus is short and presents less bulky folds and a few tubular glands. A bag-shaped uterus in the cranial area shows thin folds, and in the caudal region (shell gland) more ramified folds with few tubular glands. The vagina has long luminal folds and a thick muscular tunic; no glands with sperm-storage characteristics have been observed. In conclusion, the oviduct in sexually mature rhea has morphological similarities with the other species of birds already described; however it presents its own characteristics to produce a big egg.

Neutral and selection-driven decay of sexual traits in asexual stick insects.

Environmental shifts and lifestyle changes may result in formerly adaptive traits becoming non-functional or maladaptive. The subsequent decay of such traits highlights the importance of natural selection for adaptations, yet its causes have rarely been investigated. To study the fate of formerly adaptive traits after lifestyle changes, we evaluated sexual traits in five independently derived asexual lineages, including traits that are specific to males and therefore not exposed to selection. At least four of the asexual lineages retained the capacity to produce males that display normal courtship behaviours and are able to fertilize eggs of females from related sexual species. The maintenance of male traits may stem from pleiotropy, or from these traits only regressing via drift, which may require millions of years to generate phenotypic effects. By contrast, we found parallel decay of sexual traits in females. Asexual females produced altered airborne and contact signals, had modified sperm storage organs, and lost the ability to fertilize their eggs, impeding reversals to sexual reproduction. Female sexual traits were decayed even in recently derived asexuals, suggesting that trait changes following the evolution of asexuality, when they occur, proceed rapidly and are driven by selective processes rather than drift.

The Influence of Male Diet on Life History Traits of Female Mosquitoes

In the field, mosquitoes characteristically feed on sugars soon after emergence and intermittently during their adult lives. Sugar meals are commonly derived from plant nectar and homopteran honeydew, and without them, adults can only survive for a few days on larval reserves. In addition to sugar, females of most species rely on blood for the initiation and maintenance of egg development; thus their reproductive success depends to some extent on the availability of blood hosts. Males, on the other hand, feed exclusively on sugars. Consequently, their sexual maturation and reproductive success is largely dependent upon access to sugar sources. Plant nectar and homopteran honeydew are the two main sugar sources utilized by mosquitoes in the wild. Previous laboratory studies had shown that differences between nectar sources can affect the survivorship and biting frequency of disease vectoring mosquitoes. However, little is known on how sugar composition influence the reproductive processes in male mosquitoes. Male mosquitoes transfer accessory gland proteins and other hormones to their mates along with sperm during mating. In the female, these seminal fluid constituents exert their influence on reproductive genes that control ovulation and vitellogenesis. The present study tests the hypothesis that the mates of males consuming different sugar meals will exhibit varying levels of induction of vitellogenin (a gene which regulates the expression of egg yolk precursor proteins). Real-time quantitative RT-PCR was used to investigate how each sugar meal indirectly influences vitellogenin mRNA abundance in female Anopheles stephensi following mating. Results indicate that mates of nectar-fed males exhibit 2-fold greater change in vitellogenin expression than the mates of honeydew-fed males. However, this response did not occur in non-blood fed controls. These findings suggest that the stimulatory effect of mating on vitellogenesis in blood meal-reliant (i.e. anautogenous) mosquitoes may only be synergistic in nature. The present study also sought to compare the potential fitness costs of mating incurred by females that do not necessarily require a blood meal to initiate a reproductive cycle (i.e., exhibit autogeny). Females of the facultatively autogenous mosquito, Culex molestus were allowed to mate with males sustained on either nectar or honedyew. Mean lifetime fecundity and survivorship of females under the two different mating regimes were then recorded. Additionally, one-dimensional gel electrophoresis was used to verify the transfer of male accessory gland proteins to the sperm storage organs of females during mating.While there was no significant difference in survival between the test treatments, the mates of nectar-fed males produced 11% more eggs on average than mates of honeydew-fed males. However, additional data are needed to justify the extrapolation of these findings to natural settings. These findings prompt further investigation as the differences caused by diet variation in males may be reflected across other life history traits such as mating frequency and insemination capacity.