Mature Testis Research Articles

Habitat use of the gnomefishes Scombrops boops and S. gilberti in the northwestern Pacific Ocean in relation to reproductive strategy

The Japanese gnomefishes Scombrops boops and S. gilberti closely resemble each other but their geographical distributions in the northwestern Pacific Ocean are markedly differ- ent. In order to understand the determinants of reproductive isolation, we examined habitat use in relation to the reproductive strategy employed by these species in the Izu-Islands region, where adults of both species coexist. We examined the species compositions of the gnomefishes based on mitochondrial sequence differences, and the maturation process of gonads using the gonado - somatic index (GSI) and by histological observation of the gonads. Genetic analysis showed that large individuals (>400 mm SL) of both species were present in the region, whereas all small gnomefish (<400 mm SL) were identified only as S. boops. Thus, the Izu-Islands region is likely utilized as a nursery by S. boops but not by S. gilberti. The GSI of adult S. gilberti showed signif- icantly higher values in March compared to the consistently low values detected for S. boops. In addition, the GSI-elevated S. gilberti had mature ovaries and testes. These results suggest that the Izu-Islands region is utilized as a spawning ground by S. gilberti but not by S. boops. It appears that S. boops spawns in the upper reaches of the Kuroshio Current and that the offspring are trans- ported to the Izu-Islands region by the current. The differences between the species-specific spawning grounds, in conjunction with the transport provided by the currents, likely determine the interspecific differences in geographical distribution.

Annual development of gonads of pumpkinseed, Lepomis gibbosus (Actinopterygii: Perciformes: Centrarchidae) from a heated-water discharge canal of a power plant in the lower stretch of the Oder River, Poland

Background. The pumpkinseed, Lepomis gibbosus (Linnaeus, 1758), known also as pumpkinseed sunfish, is native to eastern and central North America. Its introduction to Europe has resulted in fast spreading of the species over the continent. In Poland, the pumpkinseed has found favourable conditions for living and reproduction in water bodies artificially heated by thermal power plants. The aim of this study was to determine the annual cycle of gonad development of the pumpkinseed population inhabiting the warm-water canal of the Dolna Odra power plant (NW Poland), which has not been studied before at this location. Materials and methods. The pumpkinseed individuals were caught in the heated-water discharge canal of the Dolna Odra power plant. The average water temperature in the canal was by 6–8ºC higher than that of the river. The analysis of the annual cycle of gonad development was performed in both sexes using histological methods. The fish were aged 3+ to 6+. A standard paraffin technique and Heidenhain’s iron hematoxylin staining were used. Results. In the site surveyed, the spawning season for females lasted from the beginning of May through August, i.e., was longer than in the native range of this fish species. In one female caught in September, the ovaries contained oocytes in the stage of vitellogenesis. The oocytes in the stage of atresia were found rarely in the fish caught from April through June. Mature testes in males were found between late April and September, i.e., throughout the spawning period of the females. Few male anomalies of the sexual cycle were observed, e.g., in October, they were found to engage in another cycle of spermatogenesis and spermatozoa production. Moreover, the presence of large groups of degenerating cells in the seminal tubules was observed throughout the year, but was particularly evident between September and February. Conclusion. The results have confirmed the high colonisation abilities of the pumpkinseed. As a consequence of global warming, the studied canal with post-cooling water may become a starting point of expansion of this species to other bodies of water. Upon a considerable climate warming, this species could threaten the native species.

Effect of pyrimethamine treatment on male rat testicular cell population development.

Pyrimethamine (PYR) is a drug used in the treatment of newborn with congenital Toxoplasmosis. Even when PYR is highly specific against parasites, it may provoke neutropenia in the patients apart from other affectations, conditions that usually justify its suspension. Moreover, medication against congenital toxoplasmosis coincides with the proliferation stage of Sertoli and germ cells. Although, there are several reports on the effect of this drug on mature testes, records of its effects on the testes of young individuals yet in the process of growth are still lacking. This work was aimed to study the effects of in vivo administration of PYR in the first 21 days of life of male rat pups by evaluating their testicular alterations and its long-term sequels on fertility. Through the determination of the levels of seminiferous epithelium maturity, apoptotic index and cell proliferation index at 7, 14, 35 and 90 days post-natal using immunocytochemical studies. The fertility of the treated rats was evaluated at 90 days. PYR-treated animals were found to undergo some kind of delays in seminiferous epithelium maturity, decreased cell proliferation index and an increase in apoptosis when compared with the control (p < 0.05). Epididymal sperm counts were also affected (p < 0.05). The application of folic acid (FA) in newborns treated with PYR decreased the severity of the problem (p < 0.05). This study provides strong evidence that the effect of PYR on testicular development is specific. It reinforces the importance of FA application in neonates treated with PYR to prevent the effect of the later on spermatogenesis.

Transient sex change in the immature Malabar grouper, Epinephelus malabaricus, androgen treatment.

To clarify the cause of sex change recovery after the withdrawal of androgen treatment, immature female Malabar grouper were fed a diet containing 17alpha-methyltestosterone (MT) at 50 μg/g for 7 mo and then a normal diet for 6 mo. The MT brought about precocious sex change from immature ovaries to mature testes with active spermatogenesis, including the development of spermatozoa, and sex change reversed soon after MT treatment withdrawal. This result indicates that precocious sex change in immature Malabar grouper with oral MT treatment is impermanent. The expression of three steroidogenic enzymes (Cyp11a, Cyp19a1a, and Cyp11b) in the gonads of the Malabar grouper were analyzed immunohistochemically at the end of the 7-mo treatment. No apparent differences were seen in the expression pattern of these enzymes between the mature testes of MT-treated fish and the immature ovaries of control fish. In addition, serum estradiol-17beta and 11-ketotestosterone levels in treated fish were the same as those in control fish. These results indicate that in the case of immature Malabar grouper MT might have little effect on endogenous steroidogenesis during precocious sex change even though it induced active spermatogenesis in the gonads of treated fish. From these results, we also concluded that MT might have little effect on the steroidogenic endocrine pathway, and this is one cause of sex change recovery after treatment withdrawal.

Identification of novel regulatory genes in development of the avian reproductive tracts.

The chicken reproductive system is unique in maintaining its functions including production of eggs or sperm, fertilization of the egg by sperm maintained in sperm nests, production of hormones regulating its growth, development and function, and reproduction. Development of the reproductive organs is a highly regulated process that results in differentiation and proliferation of germ cells in response to predominant regulatory factors such as hormones and transcription factors. However, only a few genes are known to determine morphogenesis of the chicken reproductive tract and their mechanisms are unknown. Therefore, in the present study, we investigated the expression patterns of four genes including SNCA, TOM1L1, TTR and ZEB1 in the gonads at embryonic days 14 and 18, and in immature (12-week-old) and mature (50-week-old) chickens, as well as the reproductive tract including ovary, oviduct and testes of the respective sexes by qRT-PCR, in situ hybridization and immunofluorescence analyses. The expression of SNCA, TOM1L1 and ZEB1 genes was higher in immature and mature female reproductive tracts than expression of TTR. In addition, different temporal and spatial patterns of expression of the four genes were observed during maturation of testis in chickens. Specifically, SNCA, TOM1L1 and TTR were highly expressed in testes of 12-week-old chickens. Moreover, several chicken specific microRNAs (miRs) were demonstrated to affect expression of target gene mRNAs by directly binding to the 3′-UTR of their target genes through actions at the post-transcriptional level as follows: miR-153 and miR-1643 for SNCA; miR-1680* for TTR; and miR-200b and miR-1786 for ZEB1. These results suggest that four-selected genes play an important role in development of the male and female reproductive tract in chickens and expression of most candidate genes is regulated at the post-transcriptional level through specific microRNAs.

Integrative omics analysis reveals differentially distributed proteins in dimorphic euspermatozoa of the squid, Loligo bleekeri

In the coastal squid Loligo bleekeri, each male produces one of two types of fertilization-competent spermatozoa (eusperm) that exhibit morphological and behavioral differences. Large “consort” males produce short-tailed spermatozoa that display free-swimming behavior when ejaculated into seawater. Small “sneaker” males, on the other hand, produce long-tailed spermatozoa that exhibit a self-swarming trait after ejaculation. To understand the molecular basis for adaptive traits employed by alternative male mating tactics, we performed the transcriptome deep sequencing (RNA-seq) and proteome analyses to search for differences in testicular mRNAs and sperm proteins, respectively. From mature male testes we identified a total of 236,455 contigs (FPKM ≧1) where 3789 and 2789 were preferentially (≧10-fold) expressed in consort and sneaker testes, respectively. A proteomic analysis detected 4302 proteins in the mature sperm as post-translational products. A strongly biased (≧10-fold) distribution occurred in 55 consort proteins and 61 sneaker proteins. There was no clear mRNA–protein correlation, making a ballpark estimate impossible for not only overall protein abundance but also the degree of biased sperm type expressed in the spermatozoa. A family encoding dynein heavy chain gene, however, was found to be biased towards sneakers, whereas many enzymes involving energy metabolism were heavily biased towards consort spermatozoa. The difference in flagellar length matched exactly the different amount of tubulins. From these results we hypothesize that discrete differential traits in dimorphic eusperm arose from a series of innovative alterations in the intracellular components of spermatozoa.

Sexual development, size at maturity, size at maternity and fecundity of the blue shark Prionace glauca (Linnaeus, 1758) in the Southwest Atlantic

Size at maternity and size at maturity of the blue shark Prionace glauca were studied from samples collected during ten commercial longline fishing cruises off southern Brazil and in adjacent international waters. The sharp increase of the amplitude of the values of reproductive variables at a given fork length (FL) was evidence that from that FL reproduction occurred. Thus, we calculated the proportion of mature sharks in FL classes to estimate the median size at maturity. The accelerated growth of the claspers started before the beginning of the testis maturation and semen production, whereas the accelerated development of the ovary and the oviducal glands started simultaneously. Although most females with mating marks were mature, few had sperm stored in the oviducal glands. The population parameter of size at 50% of maturity was estimated at 171.2cm FL for females and 180.2cm FL for males. The median size at maternity was estimated in 193.9cm FL and half of the females with five to six years old were recruited for reproductive phase of life. As most shark species, P. glauca in the Southwest Atlantic reach maturity at about three-fourths of its maximum size and half of its maximum age. Median litter size was 33 embryos. A positive not significant linear relationship between the uterine fecundity and the size of the pregnant female was observed.

TAp73 is essential for germ cell adhesion and maturation in testis

A core evolutionary function of the p53 family is to protect the genomic integrity of gametes. However, the role of p73 in the male germ line is unknown. Here, we reveal that TAp73 unexpectedly functions as an adhesion and maturation factor of the seminiferous epithelium orchestrating spermiogenesis. TAp73 knockout (TAp73KO) and p73KO mice, but not ΔNp73KO mice, display a "near-empty seminiferous tubule" phenotype due to massive premature loss of immature germ cells. The cellular basis of this phenotype is defective cell-cell adhesions of developing germ cells to Sertoli nurse cells, with likely secondary degeneration of Sertoli cells, including the blood-testis barrier, which leads to disruption of the adhesive integrity and maturation of the germ epithelium. At the molecular level, TAp73, which is produced in germ cells, controls a coordinated transcriptional program of adhesion- and migration-related proteins including peptidase inhibitors, proteases, receptors, and integrins required for germ-Sertoli cell adhesion and dynamic junctional restructuring. Thus, we propose the testis as a unique organ with strict division of labor among all family members: p63 and p53 safeguard germ line fidelity, whereas TAp73 ensures fertility by enabling sperm maturation.

Identification and Characterization of MicroRNAs in Ovary and Testis of Nile Tilapia (Oreochromis niloticus) by Using Solexa Sequencing Technology

MicroRNAs (miRNAs) are endogenous non-coding small RNAs which play important roles in the regulation of gene expression by cleaving or inhibiting the translation of target gene transcripts. Thereinto, some specific miRNAs show regulatory activities in gonad development via translational control. In order to further understand the role of miRNA-mediated posttranscriptional regulation in Nile tilapia (Oreochromis niloticus) ovary and testis, two small RNA libraries of Nile tilapia were sequenced by Solexa small RNA deep sequencing methods. A total of 9,731,431 and 8,880,497 raw reads, representing 5,407,800 and 4,396,281 unique sequences were obtained from the sexually mature ovaries and testes, respectively. After comparing the small RNA sequences with the Rfam database, 1,432,210 reads in ovaries and 984,146 reads in testes were matched to the genome sequence of Nile tilapia. Bioinformatic analysis identified 764 mature miRNA, 209 miRNA-5p and 202 miRNA-3p were found in the two libraries, of which 525 known miRNAs are both expressed in the ovary and testis of Nile tilapia. Comparison of expression profiles of the testis, miR-727, miR-129 and miR-29 families were highly expressed in tilapia ovary. Additionally, miR-132, miR-212, miR-33a and miR-135b families, showed significant higher expression in testis compared with that in ovary. Furthermore, the expression patterns of the miRNAs were analyzed in different developmental stages of gonad. The result showed different expression patterns were observed during development of testis and ovary. In addition, the identification and characterization of differentially expressed miRNAs in the ovaries and testis of Nile tilapia provides important information on the role of miRNA in the regulation of the ovarian and testicular development and function. This data will be helpful to facilitate studies on the regulation of miRNAs during teleosts reproduction.

Tumor Suppressor Candidate TUSC3 Expression during Rat Testis Maturation

Analysis of microarray data obtained by comparing gene expression between 2-week-old infant and 7-week-old mature SD rat testes revealed novel targets involved in tumor suppression. Reverse-transcription polymerase chain reaction and Northern blotting indicated that Tusc3 gene expression was upregulated in the normal maturing testis and prostate and other organs such as the cerebrum and ovary. Tumor suppressor candidate 3 protein expression was detected in these same organs at a size of about 40 kDa, in accord with the predicted molecular size. In situ hybridization and immunohistochemistry showed that mRNA and protein localization were prevalent in the testis spermatocytes and interstitial cells such as the Leydig cells, as well as prostate epithelial cells. These data suggest that TUSC3 is deeply involved in spermatogenesis in the testis, inducing sperm differentiation and maturation, and plays a role in normal prostate development and tumor suppression.

Role of day length in the regulation of annual testicular cycle in male black-headed munia

Annual changes in day length provide temporal information in the regulation of timing of breeding in birds. In subtropical birds, role of day length in initiation/termination of breeding is well studied in long day breeders, but not in postmonsoon breeders. This study investigated testicular growth in subtropical black-headed munia (Lonchura malacca malacca) exposed to constant day lengths. Groups of male munia were held under long (14 h of light/10 h of dark; 14L: 10D, LD) and short days (10L: 14D, SD) for 16 months. A group held under natural illumination conditions (NDL) served as control. Testicular growth occurred in all photoperiods, although the rate of growth was slower, and hence, testis maturation was delayed under SD. Testis recrudescence–regression cycle occurred under SD, as in NDL control birds, but not in LD in which testis did not regress. It is suggested that day length plays an important role in the regulation of annual testicular cycle in black-headed munia, although with a difference from long day species described thus far. Simultaneous observations of wing primary molt in these groups showed that molt and testicular cycles were unrelated with each other, unlike suggested in other photoperiodic species.

Editorial Comment

Testis tumors in children are rare, with an incidence of 0.5-2.0 per 100, 000.1Ross J.H. Prepubertal testicular tumors.Urology. 2009; 74: 94-99Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Treatment of testis tumors in children has evolved from radical orchiectomy, as is done in adults and adolescents, to testis sparing surgeries in most children with benign testis lesions found before puberty. Although the Prepubertal Testis Tumor Registry found that yolk sac tumors are the most frequently reported pediatric testis tumor,2Ross J.H. Rybicki L. Kay R. Clinical behavior and a contemporary management algorithm for prepubertal testis tumors: a summary of the Prepubertal Testis Tumor Registry.J Urol. 2002; 168: 1675-1679Abstract Full Text Full Text PDF PubMed Google Scholar other investigators have found that teratoma tumors are actually more common in their facilities pediatric tumor occurrence.3Pohl H.G. Shukla A.R. Metcalf P.D. et al.Prepubertal testis tumors: actual prevalence rate of histological types.J Urol. 2004; 172: 2370-2372Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar, 4Taskinen S. Fagerholm R. Aronniemi J. et al.Testicular tumors in children and adolescents.J Ped Urol. 2008; 4: 134-137Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar, 5Metcalf P.D. Farivar-Mohseni H. Farhat W. et al.Pediatric testicular tumors: contemporary incidence and efficacy of testicular preserving surgery.J Urol. 2003; 170: 2412-2416Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar, 6Valla J. Testis-sparing surgery for benign testicular tumors in children.J Urol. 2001; 165: 2280-2283Abstract Full Text Full Text PDF PubMed Google Scholar The incidence of teratoma, generally mature teratoma, is 39%-48% in these series. Evaluation of children before surgical treatment will give the urologic surgeon a better idea on whether the testis might be salvaged with tumor enucleation or excision. Preoperative examination of the testes with ultrasound imaging was discussed in some of the other series but no particular descriptions were given on typical ultrasound findings in testes with teratoma.4Taskinen S. Fagerholm R. Aronniemi J. et al.Testicular tumors in children and adolescents.J Ped Urol. 2008; 4: 134-137Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar, 5Metcalf P.D. Farivar-Mohseni H. Farhat W. et al.Pediatric testicular tumors: contemporary incidence and efficacy of testicular preserving surgery.J Urol. 2003; 170: 2412-2416Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar, 6Valla J. Testis-sparing surgery for benign testicular tumors in children.J Urol. 2001; 165: 2280-2283Abstract Full Text Full Text PDF PubMed Google Scholar The authors describe ultrasound findings in children with mature teratoma testis tumors as commonly having varying degrees of cystic elements, calcifications, and rare vascularity in the mass. All children were also evaluated with alpha-fetoprotein (AFP) serum tumor marker assessment as is recommended to assure that the testis tumor is not malignant with yolk sac elements. Although this series was small with only 7 cases, all the cases were found to have mature teratoma on final pathology. It is reasonable to deduce that mature teratoma with endodermal mesodermal and ectodermal tissue derivatives would have cystic and calcified elements found on ultrasound according to its composition. It is worthwhile noting that although mature teratoma can be treated by testis sparing surgery in most instances, immature teratoma should not be considered or treated the same as mature teratoma. Although there have not been any reported cases of metastasis or recurrence in children younger than 12 years with mature teratoma, that has been a reported case of metastatic immature teratoma with neuroectodermal elements.7Kato K. Ijiri R. Tanaka Y. et al.Testicular immature teratoma with primitive neuroectodermal tumor in early childhood.J Urol. 2000; 164: 2068-2069Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar This tumor represents <10% of tumors reported to the Pediatric Oncology Group/Children's Cancer Group. It was recommended to completely remove this tumor and not to perform testis sparing surgery. All testis tumors, regardless of ultrasound findings, should at a minimum have an AFP serum marker test and surgical excision with an inguinal approach, vascular control with a tourniquet, and excisional biopsy with frozen section pathologic assessment of the mass performed with a nonmalignant assessment of the testis tissue done before consideration for testis sparing surgery. If there is an abnormal elevation of the AFP or any tissue components suspicious for malignancy, the entire testis should be removed. The authors have given us some reassuring ultrasound element assessments found in mature teratoma which help in planning a testis surgical procedure for the patient, barring elevated AFP or tissue findings not consistent with a benign testis tumor in childhood. Mature Testicular Teratoma in Children: Multifaceted Tumors on UltrasoundUrologyVol. 83Issue 1PreviewTo describe the different ultrasound (US) findings of mature testicular hamartomas in children. Full-Text PDF

Smurf-mediated differential proteolysis generates dynamic BMP signaling in germline stem cells during Drosophila testis development

Germline stem cells (GSCs) produce gametes throughout the reproductive life of many animals, and intensive studies have revealed critical roles of BMP signaling to maintain GSC self-renewal in Drospophila adult gonads. Here, we show that BMP signaling is downregulated as testes develop and this regulation controls testis growth, stem cell number, and the number of spermatogonia divisions. Phosphorylated Mad (pMad), the activated Drosophila Smad in germ cells, was restricted from anterior germ cells to GSCs and hub-proximal cells during early larval development. pMad levels in GSCs were then dramatically downregulated from early third larval instar (L3) to late L3, and maintained at low levels in pupal and adult GSCs. The spatial restriction and temporal down-regulation of pMad, reflecting the germ cell response to BMP signaling activity, required action in germ cells of E3 ligase activity of HECT domain protein Smurf. Analyses of Smurf mutant testes and dosage-dependent genetic interaction between Smurf and mad indicated that pMad downregulation was required for both the normal decrease in stem cell number during testis maturation in the pupal stage, and for normal limit of four rounds of spermatogonia cell division for control of germ cell numbers and testis size. Smurf protein was expressed at a constant low level in GSCs and spermatogonia during development. Rescue experiments showed that expression of exogenous Smurf protein in early germ cells promoted pMad downregulation in GSCs in a stage-dependent but concentration-independent manner, suggesting that the competence of Smurf to attenuate response to BMP signaling may be regulated during development. Taken together, our work reveals a critical role for differential attenuation of the response to BMP signaling in GSCs and early germ cells for control of germ cell number and gonad growth during development.

Estradiol and testosterone inhibit rat seminiferous tubule development in a hormone-specific way

Follicle stimulating hormone (FSH), testosterone (T) and estradiol (E2) are known to regulate testis maturation, and changes in FSH secretion induced by sex steroid treatment may mediate the effects of sex hormones. The aim of this study was to compare the effects of T and E2 on the pre-meiotic steps of first spermatogenesis and FSH level in rats. Male rat pups were injected daily with 17β-estradiol benzoate (EB; 12.5μg) or testosterone propionate (TP; 2.5mg) with the use of one of the two administration modes: 1/transient mode; hormone injections on postnatal days (PND) 1–5 followed by daily vehicle injections until PND 15 (t-EB and t-TP, respectively) or 2/continuous mode; hormone injections on PND 1–15 (c-EB and c-TP, respectively). The control group was injected with vehicle alone. On PND 16, blood was taken for serum hormone measurement and testes were collected for analysis of seminiferous tubule morphometry as well as cell number, proliferation and apoptosis. Testis weight, tubule length, Sertoli and germ cell numbers were reduced, and cell apoptosis in seminiferous epithelium was increased after transient EB and TP treatments. Despite normal or increased FSH secretion, the c-EB treatment inhibited pre-meiotic germ cell development and augmented cell apoptosis, whereas the c-TP treatment reduced the spermatocyte number and inhibited the formation of seminiferous tubule lumen. In conclusion, transient administration of EB or TP during PND 1–5 inhibited testis growth, whereas continuous administration (PND 1–15) impaired pre-meiotic germ cell development in a hormone-specific way.

Transcriptomic profiling of progesterone in the male fathead minnow (Pimephales promelas) testis

P4 is a hormone with diverse functions that include roles in reproduction, growth, and development. The objectives of this study were to examine the effects of P4 on androgen production in the mature teleost testis and to identify molecular signaling cascades regulated by P4 to improve understanding of its role in male reproduction. Fathead minnow (FHM) testis explants were treated in vitro with two concentrations of P4 (10−8 and 10−6M) for 6 and 12h. P4 significantly increased testosterone (T) production in the FHM testis but did not affect 11-ketotestosterone. Gene network analysis revealed that insulin growth factor (Igf1) and tumor necrosis factor receptor (Tnfr) signaling was significantly depressed with P4 treatment after 12h. There was also a 20% increase in a gene network for follicle-stimulating hormone secretion and an 18% decrease in genes involved in vasopressin signaling. Genes in steroid metabolism (e.g. star, cyp19a, 11bhsd) were not significantly affected by P4 treatments in this study, and it is hypothesized that pre-existing molecular machinery may be more involved in the increased production of T rather than the de novo expression of steroid-related transcripts and receptors. There was a significant decrease in prostaglandin E synthase 3b (cytosolic) (ptges3b) after treatment with P4, suggesting that there is cross talk between P4 and prostaglandin pathways in the reproductive testis. P4 has a role in regulating steroid production in the male testis and may do so by modulating gene networks related to endocrine pathways, such as Igf1, Tnfr, and vasopressin.

Gonad maturation of Haemulon plumieri (Teleostei: Haemulidae) in Ceará state, Northeastern Brazil

To elucidate the reproductive cycle of any animal, it is first necessary to understand the development of the germ cells and how this process occurs throughout the reproductive tract. Thus, the aim of the present study was to understand the oogenesis and spermatogenesis, as well as the ovarian and testis maturation and type of spawning, of Haemulon plumieri. A total of 119 females and 136 males were analysed. Based on micro and macroscopic characteristics of gonads, the following stages of maturation for females were determined: immature, maturing, ripe, partially spawning, spawning and resting. For males, only the stages immature, maturing, ripe and spent were observed. We can conclude that the ovarian development occurs cyclically, in which the female can spawn more than two times during the reproductive season with the spawning "synchronous in more than two groups". Since males do not present the "rest" stage after copulation, the maturation process is continuous.

Ultrastructure of germ cells, Sertoli cells and mitochondria during spermatogenesis in mature testis of the Chinese Taihang black goats (Capra hircus)

The objective of this study was to describe the ultrastructure of germ cells, Sertoli cells and mitochondria in mature testis of the Chinese Taihang black goat. The characteristics of germ cell nucleus and mitochondria changing during spermatogenesis were investigated by transmission electron microscopy (TEM). The results showed that the spermatogonium was elliptical, and its nucleus was about 4–5μm. The round mitochondria can be observed throughout the cytoplasm around the nucleus. Small patches of heterochromatin were distributed throughout the nucleus. Spermatocyte was oval-shaped with a nucleus of about 4–4.5μm in diameter. The heterochromatin began to attach to the inner surface of the nuclear membrane. Spermatid was about 4μm and oval in shape. Its nucleus was oval or round and approximately 2–3μm in diameter. The borderline between nucleus membrane and karyoplasm was distinct. During spermiogenesis, spermatid nucleus was condensed and elongated, and chromatin reached the highest condensation in the mature spermatozoon. The mid-piece was surrounded by mitochondria at the neck region. The sperm tail showed the typical “9+2″ structure, contained axoneme and central singlet microtubules. The nuclei of the Sertoli cells were irregular shaped and showed indentations in the membrane. In the mature testes of goat bucks, abundant mitochondria were around the germ cells and Sertoli cells. The scattered mitochondria were aggregated around the base of the flagellum (axoneme) during the spermatid differentiation stage. In conclusion, the present study showed that the spermatogenic process of Taihang black goat followed the pattern of mammals with some specific.

Thyroid hormones and male reproductive system

For years it was regarded that testis was unresponsive organ to thyroid hormone (TH). Recent studies have changed this view by demonstration that triiodothyronine (T3), beside follicle stimulating hormone (FSH) from pituitary, plays an essential role in testes maturation.

GH overexpression decreases spermatic parameters and reproductive success in two-years-old transgenic zebrafish males

Growth hormone (GH) transgenesis has been postulated as a biotechnological tool for improving growth performance in fish aquaculture. However, GH is implied in several other physiological processes, and transgenesis-induced GH excess could lead to unpredictable collateral effects, especially on reproductive traits. Here, we have used two-years-old transgenic zebrafish males to evaluate the effects of GH-transgenesis on spermatic parameters and reproductive success. Transgenic spermatozoa were analyzed in terms of motility, motility period, membrane integrity, mitochondrial functionality, DNA integrity, fertility and hatching rate. We have also performed histological analyses in gonad, in order to verify the presence of characteristic cell types from mature testes. The results obtained have shown that, even in transgenic testes present in all cells in normal mature gonads, a significant general decrease was observed in all spermatic and reproductive parameters analyzed. These outcomes raise concerns about the viability of GH-transgenesis appliance to aquaculture and the environmental risks at the light of Trojan gene hypothesis.

Constitutive activation of NOTCH1 signaling in Sertoli cells causes gonocyte exit from quiescence

Notch signaling components have long been detected in Sertoli and germ cells in the developing and mature testis. However, the role of this pathway in testis development and spermatogenesis remains unknown. Using reporter mice expressing green fluorescent protein following Notch receptor activation, we found that Notch signaling was active in Sertoli cells at various fetal, neonatal, and adult stages. Since Notch signaling specifies stem cell fate in many developing and mature organ systems, we hypothesized that maintenance and differentiation of gonocytes and/or spermatogonial stem cells would be modulated through this pathway in Sertoli cells. To this end, we generated mutant mice constitutively expressing the active, intracellular domain of NOTCH1 (NICD1) in Sertoli cells. We found that mutant Sertoli cells were morphologically normal before and after birth, but presented a number of functional changes that drastically affected gonocyte numbers and physiology. We observed aberrant exit of gonocytes from mitotic arrest, migration toward cord periphery, and premature differentiation before birth. These events, presumably unsupported by the cellular microenvironment, were followed by gonocyte apoptosis and near complete disappearance of the gonocytes by day 2 after birth. Molecular analysis demonstrated that these effects are correlated with a dysregulation of Sertoli-expressed genes that are required for germ cell maintenance, such as Cyp26b1 and Gdnf. Taken together, our results demonstrate that Notch signaling is active in Sertoli cells throughout development and that proper regulation of Notch signaling in Sertoli cells is required for the maintenance of gonocytes in an undifferentiated state during fetal development.