Specifically, uni is the gonad part of the sea urchin.
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Then, from the gonad, which looks like a little sac, he removes a black bit: The fat.
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Because of their oversized tongues, ovaries and testes, biologists have affectionately nicknamed Thorius the "tongue-flipping gonad" of salamanders.
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The oyster appears complete and he points out its parts: The mantle, the muscle, the gonad, and the fat.
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An oyster's gonad — its largest organ — makes up 30 to 40 percent of its body mass when fully developed.
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The Verge spoke with Rabaiotti, Caruso, and Kocak on a conference call about fart-catching devices and gonad-eating parasites.
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Some Chinese love earthworm broth, and Zanzibaris feast on white-ant pie; the French have been known to eat eels with sea-urchin-gonad sauce, and some Hawaiians have a taste for broiled puppy.
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In a couple of them Guston's Nixon is a hooded Klansman conspiring with his cronies Spiro T. Agnew and John Mitchell, but in most he is a kind of walking gonad, his nose a penis that grows longer with every lie he tells.
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I try to be honest about my time in science — about the feeling of satisfaction I had when I plotted all of my confocal data and there was a beautiful curve depicting the drop-off in signal as one moved further down the tissue of the gonad.
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Genes associated with the developing gonad can be categorized into those that form the sexually indifferent gonad, those that determine whether the indifferent gonad will differentiate as male or female, and those that promote differentiation into male or female parts. Genes that form the sexually indifferent gonad are SF1 and WT1. Genes that determine sex are SRY, SOX9, and DAX1. Genes driving the differentiation into male or female structures are SF1, WT1, and WNT4.
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A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes (sex cells) and sex hormones of an organism. In the female of the species the reproductive cells are the egg cells, and in the male the reproductive cells are the sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells.
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Vintage framed copies of Buster Gonad cartoon from the 1980s are now collectable items.
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Without TCF21, normal gonad development is disrupted as a result of ectopic expression of Sf1, which leads to abnormal committing of urogenital progenitor cells to steroidogenic cell fates. In the XY gonad, this disruption in organization contributes to changes in testicular structure and vasculature.
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Intra-operative gross photograph of the spleen attached to the left testis in a 1-year old boy with splenogonadal fusion Splenogonadal fusion is a rare congenital malformation that results from an abnormal connection between the primitive spleen and gonad during gestation. A portion of the splenic tissue then descends with the gonad. Splenogonadal fusion has been classified into two types: continuous, where there remains a connection between the main spleen and gonad; and discontinuous, where ectopic splenic tissue is attached to the gonad, but there is no connection to the orthotopic spleen. Patients with continuous splenogonadal fusion frequently have additional congenital abnormalities, most commonly cryptorchidism.
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Only the left gonad in both sexes is developed, and in males, the right gonad is sometimes wholly absent.Smith, C.L. 1997National Audubon Society field guide to tropical marine fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Alfred A. Knopf, Inc., New York.
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The round ligament develops from the gubernaculum which attaches the gonad to the labioscrotal swellings in the embryo.
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Male gonad (testes, left) and female gonad (ovaries, right) Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry is not unusual: one testicle extends farther down into the scrotum than the other due to differences in the anatomy of the vasculature.
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B. secunda is gonochoristic, and all animals are either male or female. The reproductive system of both males and females consists only of a single large disk-shaped gonad organ located above the animal's foot and extending around the lower posterior part of the visceral mass. When the gonad is ripe, the reproductive cells— sperm or eggs— burst from the organ and are released through a single gonoduct directly into the surrounding water. Reproduction requires no physical contact between sexes, and neither sex has any specialized sex organ other than the gonad itself.
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The most significant function of the aorta gonad mesonephros region is its role in definitive haematopoiesis. Definitive haematopoiesis is the second wave of embryonic haematopoiesis and give rise to all hematopoietic stem cells in the adult hematopoietic system. The aorta gonad mesonephros region has been shown to harbour multipotent hematopoietic colony-forming unit-spleen (CFU-S) progenitor cells and pluripotential long-term repopulating hematopoietic stem cells (LTR-HSCs). In contrast to the yolk sac, the extra-embryonic haematopoietic site, the number of CFU-S was much greater in the aorta gonad mesonephros region.
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The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation. If none develops, then the animal becomes sterile.
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The copulatory organ is absent in this species. The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation.
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The first appearance of the gonad is essentially the same in the two sexes, and consists in a thickening of the mesothelial layer of the peritoneum. The thick plate of epithelium extends deeply, pushing before it the mesoderm and forming a distinct projection. This is termed the gonadal ridge. The gonadal ridge, in turn, develops into a gonad.
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Through directional migration - which requires multiple genes to work, one being the Columbus (clb) gene, which codes for Drosophila HMG CoA reductase - the germ cells move towards the somatic gonadal precursor cells and associate with them. These two associated cell types then migrate together anteriorly, until they coalesce into the embryonic gonad at the future site of the mature gonad.
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Journal of the World Aquaculture Society. Vol. 40. No. 3. Morphologic changes in reproductive periods include females changes in gonad colour and oocyte numbers, while in males there is an increase in the amount of spermatozoa in particular zones described as "wet mounts of 'mashed' gonad tissue". Furthermore, there is an increase in spermatozoa in the lumen of histological sections.
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SRY is the only gene expressed solely in the developing gonad. The other genes have roles in development that are not exclusively sex-related.
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Depending on conditions, one organism can produce thousands of gametes. Sea cucumbers have one gonad Sea cucumbers are typically dioecious, with separate male and female individuals. The reproductive system consists of a single gonad, consisting of a cluster of tubules emptying into a single duct that opens on the upper surface of the animal, close to the tentacles. Many species fertilise their eggs internally.
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Genetic significant dose (GSD), or genetically significant dose, was initially defined by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) in 1958. It represents an estimate of the genetic significance of gonad radiation doses. Annual GSD is calculated by weighting the individual gonad doses received during ionizing imaging by the number of individual examined, and accounting for the number of offspring for each individual.
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Mediastinal germ cell tumors are tumors that derive from germ cell rest remnants in the mediastinum. They most commonly occur in the gonad but occasionally elsewhere.
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Testicular germ cell cancer (TGCC) shows a strong genetic disposition, with the most significant gene variants being those linked to gonad formation and germ cell function.
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Regular sea urchins have five gonads, lying underneath the interambulacral regions of the test, while the irregular forms have only four, with the hindmost gonad being absent.
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It has been suggested that embryos with a higher expression of Dmrt1 expression develop into males while embryos with a lower expression are led to female development. In the mouse gonadal primordium, the genital ridge, which forms from intermediate mesoderm, becomes morphologically distinct at E10.5. By E12, sexual differentiation of the gonad is apparent, indicating that genes involved in the formation of the bipotential gonad is expressed before E10.5 and E12.
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The percentage then increases slightly from about 3% to 12% in February before decreasing to around 4% between March and April. Highest reproductive activity occurs around July through late September, when the gonad mass is at its greatest. Gonad development begins when the shells of Arca zebra are at 18-20mm, and full sexual maturity is reached when the shells are 50-55mm. Larger individuals have greater reproductive output.
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An associated reproductive pattern is a seasonal change in reproduction which is highly correlated with a change in gonad and associated hormone.Alcock, John. 2005. Animal Behavior. Sinauer Associates.
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The SF1 protein, on its own, leads to minimal transcription of the SOX9 gene in both the XX and XY bipotential gonadal cells along the urogenital ridge. However, binding of the TDF-SF1 complex to the testis-specific enhancer (TESCO) on SOX9 leads to significant up-regulation of the gene in only the XY gonad, while transcription in the XX gonad remains negligible. Part of this up-regulation is accomplished by SOX9 itself through a positive feedback loop; like TDF, SOX9 complexes with SF1 and binds to the TESCO enhancer, leading to further expression of SOX9 in the XY gonad. Two other proteins, FGF9 (fibroblast growth factor 9) and PDG2 (prostaglandin D2), also maintain this up-regulation.
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Hedgehog also participates in the coordination of eye, brain, gonad, gut and tracheal development. Downregulation of hedgehog has been implicated in reduced eye development in the amphipod Gammarus minus.
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P. lateolabracis can be distinguished from the former by the lateral caudal mounds separated dorsally, narrower lamella-like structures on its gubernaculum, shorter spicules, and by the testis extending anteriorly. Other gonad-infecting species differ from this one by possessing a smooth gubernaculum, and their spicules being of different lengths. Seven gonad- infecting species of Philometra can be distinguished from P. priacanthi by their host types, as well as by geographical distribution.
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Confined to freshwater, with an unknown spawning period likely to be late spring to early summer. Adult fish collected in mid March were found to have mid stage gonad development.
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The brain is relatively large, and, as in many arthropods, surrounds the oesophagus. In both sexes, the single gonad lies next to the intestine and opens on the underside of the opisthosoma.
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Following spawning in the late winter and early spring, male Florida gars undergo a decrease in their reproductive parameters throughout the summer. This includes a decrease in reproductive hormone levels and gonad maturation.
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Anatomical Record 34: 337-358. which has been suggested to reduce the spontaneous rate of germ cell mutations.Ehrenberg L., von Ehrenstein G., Hedgram A. (1957). Gonad temperature and spontaneous mutation-rate in man.
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Eternity began publishing in 1986, debuting with such titles as Earthlore, Gonad the Barbarian, The Mighty Mites, Ninja, and Reign of the Dragonlord (with only Ninja lasting more than a couple of issues).
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These tumors can be benign or malignant. On arrival at the gonad, primordial germ cells that do not properly differentiate may produce germ cell tumors of the ovary or testis in a mouse model.
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PGCs that are able to migrate the fastest and reach the gonad are more likely to colonise it and give rise to future gametes. The PGCs that go off route or don’t reach the gonad undergo programmed cell death (apoptosis). It is thought that every step after specification may function as a selective mechanism to ensure germ cells are of the highest quality. The selective mechanisms may also be important for removing PGCs with abnormal epigenetic marks and in doing so preserving the germline.
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Arca zebra is a protandric hermaphrodite, a type of sequential hermaphrodite with individuals starting out as males and developing female reproductive capacity later in the life cycle. Reproduction is dependent on food availability and seasonal changes. The gonad tissues of Arca zebra change in mass throughout the year. The percentage of somatic tissue mass composed of gonad tissue mass sees a large increase from roughly 4% to 40% from May through late September and a large decrease from roughly 40% to 3% from October through January.
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Academic Press, London, pp. 343–355. Secombes, C.J., Lewis, A.E., Needham, E.A., Laird, L.M. and Priede, I.G. (1985). Appearance of autoantigens during gonad maturation in the rainbow trout (Salmo gairdneri). J. Exp. Zoology 233: 425-431.
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Secombes, C.J., Lewis, A.E., Laird, L.M., Needham, E.A. and Priede, I.G. (1985). Experimentally induced immune reactions to gonad in rainbow trout (Salmo gairdneri). In: The FSBI Symposium on Fish Immunology. (ed. by M.J. Manning and M.F. Tatner).
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PGCs are described as the dedicated cells in early embryonic development, responsible for reaching the developing gonad. During their migration however, heterogeneity of cellular behaviour is observed due to change in cellular morphology from the time of specification to colonization. By the end of PGC migration, around 5% of migratory cells remain outside the gonad and later undergo apoptosis. The apoptotic route during the migratory period is occurring via an intrinsic pathway; nonetheless, the elimination of PGCs can be unsuccessful and result in tumour formation known as teratomas, derivatives of the three germ layers.
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A male typically inherits an X chromosome from ovum and a Y chromosome from spermatozoon. The presence of the sex-determining-region of the Y chromosome, or SRY gene, determines the embryo being a male. Internal and external male genitalia development from bipotential gonad in embryo. SRY gene encodes testis-determining SRY factor (TDF) protein that promotes expression of several other genes such as SRY-box 9 (SOX-9) gene and steroidogenic factor-1 (SF1) gene, causing differentiation of the medulla of bipotential gonad into testis by week six.
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This is not uncommon among the serranids. Rypticus is unique, though, in that a fish has both male and female reproductive tissues which are separate on the cellular level, but are wrapped around each other in the gonad.
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Nader received some criticism from gay rights supporters for calling gay rights "gonad politics" and stating that he was not interested in dealing with such matters. However, more recently, Nader has come out in support of same-sex marriage.
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The cells that give rise to the gametes are often set aside during embryonic cleavage. During development, these cells will differentiate into primordial germ cells, migrate to the location of the gonad, and form the germline of the animal.
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Philometra inexpectata, a nematode parasite of the mottled grouper As most fish, the mottled grouper harbours a variety of parasites. These include the diplectanid monogenean Pseudorhabdosynochus regius on the gills and the philometrid nematode Philometra inexpectatata in the gonad.
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They have a single gonad, the gill slits are absent and the collar has two tentaculated arms. Modern Text Book of Zoology: Invertebrates Rhabdopleura is the best studied pterobranch in developmental biology. Some claim Rhabdopleura is an extant graptolite.
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He is married and has children living in West Germany. Other minor characters include Gonad, Schmuckstein, Threllmer and Fooman, who are all technicians aboard the Troll-1 – Kremmen's spaceship, which is more than a little reminiscent of a portable cassette recorder.
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WT1 is transcription factor that has four C-terminal Zinc fingers and an N-terminal Pro/Glu-rich region and primarily functions as an activator. Mutation of the Zinc fingers or inactivation of WT1 results in reduced male gonad size.
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This means that the sex of the animal is determined from an undifferentiated gonad. Differentiation then occurs and an eel becomes male or female, and this is generally correlated to the size (20.0–22.5 cm) of the animal not its age.
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Mutations in this gene have been linked to severe spermatogenic failure and infertility in males. In mice and pigs deficient in DAZL, PGCs migrate to the gonad but do not undertake germ cell determination, and may instead produce germ cell tumors.
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Clomifenoxide (INN), also known as clomifene N-oxide, is a nonsteroidal selective estrogen receptor modulator (SERM) of the triphenylethylene group that is described as an antiestrogen and "gonad stimulant" and was never marketed. It is an active metabolite of clomifene.
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CED-12 also functions in cell migration processes, which is regulated by the same interactions as the apoptotic phagocytosis pathway. It functions in distal tip cell migration in gonad development in C. elegans. Distal tip cells are somatic cells located at the tip of developing gonadal arms, and are responsible for the elongation of the gonadal arm as well as controlling mitotic and meiotic cell division of gonadal cells throughout development and adulthood. As C. elegans develops, the distal cells undergo a series of migrations in order to complete morphological changes, which define both gonad shape and size.
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The hermaphroditic worm is considered to be a specialized form of self- fertile female, as its soma is female. The hermaphroditic germline produces male gametes first, and lays eggs through its uterus after internal fertilization. Hermaphrodites produce all their sperm in the L4 stage (150 sperm cells per gonadal arm) and then produce only oocytes. The hermaphroditic gonad acts as an ovotestis with sperm cells being stored in the same area of the gonad as the oocytes until the first oocyte pushes the sperm into the spermatheca (a chamber wherein the oocytes become fertilized by the sperm).
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She conducted in Norway the first experiments on autoimmune sterilization of salmon by injection.Laird L.M., Wilson, A.R. & Holliday, F.G.T. (1980). Field trials of a method of induction of autoimmune gonad rejection in Atlantic salmon (Salmo salar L.) Reprod. Nutr. Develop., 20, 1761-1788.
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Active migration takes place as PGCs move towards the developing somatic gonad. Effective migration requires cell elongation and polarity. Environmental guidance cues are required for the PGCs to initiate and sustain their mobility. Specific molecular pathways are activated to give PGCs motility.
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Like many other members of the class Holothuroidea, blue sea cucumbers are gonochoric, and only have a single gonad. During spawning season, eggs and sperm are externally released into the surrounding water by female and male individuals, respectively, and are fertilized when they meet.
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SRY expression is expressed exclusively in the developing gonad, lacking a presence in any other tissue in embryos or adults. The presence of SRY in the genital ridge results in testis formation by directing the differentiation of Sertoli cells in a bipotential genital ridge.
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Cached seeds provide energy for gonad development, courtship, nest building, egg laying and incubation. Pinyon jays travel up to 7.5 miles (12 km) to cache pinyon and ponderosa pine seeds for later use.Lanner, Ronald M. (1981). The pinon pine: A natural and cultural history.
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After migration primordial germ cells will become oogonia in the forming gonad (ovary). The oogonia proliferate extensively by mitotic divisions, up to 5-7 million cells in humans. But then many of these oogonia die and about 50,000 remain. These cells differentiate into primary oocytes.
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Those becoming myoid cells would sit on a basement membrane surrounding the developing seminiferous tubules. However, more recent evidence has found that mesonephric cells do not give rise to PTMs but instead have only a vascular fate, leaving more uncertainty over where PTMs come from. The main difficulty in studying the development of PTMs is the lack of a molecular marker specific to them that is visible during early differentiation of the testis. Current knowledge suggests that PTMs arise from cells within the developing gonad itself, or alternatively from a layer of cells surrounding the outside of the gonad, called coelomic epithelium, by a process named epithelial-mesenchymal transition.
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The hermaphroditic duct, a highly glandular duct of comparatively even diameter, traverses the greater portion of the first coil of the body to enter the accessory glands. All of these structures are in a quiescent condition, and in size and configuration probably fall far short of their fully developed state in the sexually mature condition. The same is likewise true of the gonad. While the duct leading to it from the accessory glands is clearly apparent throughout the first part of its course, it gradually approaches the vanishing point, and cannot with certainty be traced to a gonad, which is accordingly drawn in its hypothetical position.
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Lesions observed in the testis of precociously maturing male Atlantic salmon, Salmo salar L. J.Fish Biol. 17, 343-348. Laird L.M., Wilson, AR & Holliday, FGT (1980). Field trials of a method of induction of autoimmune gonad rejection in Atlantic salmon (Salmo salar L.) Reprod. Nutr. Develop.
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This keeps spermatogenesis from starting too soon. In females, the mesonephros releases RA, which enters the gonad. RA stimulates Stra8, a critical gatekeeper of meiosis (1), and Rec8, causing primordial germ cells to enter meiosis. This causes the development of oocytes that arrest in meiosis I. 1\.
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The ciliate parasite Orchitophrya stellarum has been found in the gonads of up to 20% of male Asterias forbesi in Long Island Sound. They feed on the tissue of the gonad and effectively castrate their host. A small number of females were also found to contain the parasite.
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This movement is coordinated by the expression of the chemo- attractant SDF1A (stromal derived factor 1a). The final migration towards the developing gonad occurs 13 hours-post-fertilisation after which point the germ cells coalesce with the somatic gonadal precursor cells. The entire process takes around 24 hours.
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In birds, the PGCs arise from the epiblast and migrate to anteriorly of the primitive streak to the germinal crest. From there, they use blood vessels to find their way to the gonad. The CXCR4/Sdf1 system is also used, though may not be the only method necessary.
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Tissue expression is highest within the oocyte, with high expression in the testes and female gonad. Tissue expression of Q5T4I8 in humans. Expression is highest in the oocyte. Expression is extremely high (2000-3000 transcripts per million) in the first stages of embryonic development up until the blastocyst.
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The aorta-gonad-mesonephros (AGM) is a region of embryonic mesoderm that develops during embryonic development from the para-aortic splanchnopleura in chick, mouse and human embryos. It has been suggested that this area, in particular the ventral wall of the dorsal aorta, is one of the primary origins of the definitive haematopoietic stem cell. The aorta-gonad-mesonephros (AGM) region is an area derived from splanchnopleura mesoderm identified in embryonic humans, mice, and non-mammalian vertebrates such as birds and zebrafish. It contains the dorsal aorta, genital ridges and mesonephros and lies between the notochord and the somatic mesoderm, extending from the umbilicus to the anterior limb bud of the embryo.
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Amphibian sex reversal can be also induced by exposure to sex steroid and pollutants. Endocrine disruptors can affect gonad differentiation, and therefore induce sex reversal. Exposure to ethylnyl estradiol (EE2) and bisphenol A (BPA) induces feminizing effects. Masculinizing effects can be induced by exposure to the drug trenbolone, used in cattle.
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A pearl being extracted from an akoya pearl oyster. Today, the cultured pearls on the market can be divided into two categories. The first category covers the beaded cultured pearls, including akoya, South Sea and Tahiti. These pearls are gonad grown, and usually one pearl is grown at a time.
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Smith Lake (Athabascan Tr'exwghodegi Troth Yeddha' Bena') is a lake in Fairbanks, Alaska, U.S. on the property of the University of Alaska Fairbanks. It is triangular in shape, roughly 300 x 300 x 380 m.Tohko Kaufmann (1971). "Ecology, Biology and Gonad Morphology of Gerris rufoscutellatus (Hemiptera: Gerridae) in Fairbanks, Alaska".
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For example, increased protein content of the microalgal diet of broodstock has been shown to reduce time to spawning maturity and increase fecundity.Farías A & Uriarte I (2001). Effect of microalgae protein on the gonad development and physiological parameters of Chilean scallop Argopecten purpuratus (Lamark, 1819). Journal of Shellfish Research, 20:97-105.
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Orthonectida are found in the body spaces of various marine invertebrates including tissue spaces, gonads, genitorespiratory bursae. This pathogen causes host castration of different species. The best known of Orthonectida is the parasite of brittle stars. The multinucleate syncytial stage lives within tissues and spaces of the gonad but can spread into arms.
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Hormone-induced sex reversal is the most frequent method used in aquaculture. It consists of exposing sexually undifferentiated fishes to sex steroids. There are other methods to induced sex reversal in fishes such as chromosomal/genetic manipulation, hybridization, or treatments influencing sex determination or gonad differentiation (e.g. temperature, population density, pH, social factors).
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The softening is a state-transformation of the collagen components in the tissue. #Parts eviscerated include the gut, associated haemal vessels, tentacles, and introvert (the dexterous anterior extensible portion of the body wall). The gut tears away from the mesenteries that suspend it within the coelomic cavity. #Most of the gonad stays behind.
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Greenwood, A. W. 1928 Studies on the relation of gonadic structure to plumage characterization in the domestic fowl. IV. Gonad cross-transplantation in Leghorn and Campine. Proc. Roy. Soc.(London) B, 103, 73-81. Caridroit, F. 1937 Contróle des caractères pigmentaires raciaux par une hormone masculinisante (propionate de testostérone). Compt. Rend. Soc. Biol.
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HzNV-2 is closely related to HzNV-1; it is likely that HzNV-1 is a variant of HzNV-2 which exists in a persistent state in infected moths. HzNV-2 was discovered in 1995. Originally, symptomatic hosts were described as being "agonadal". Then, the virus was given the name "gonad specific virus".
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Male flower urchin (Toxopneustes roseus) releasing milt, November 1, 2011, Lalo Cove, Sea of Cortez Sea urchins are dioecious, having separate male and female sexes, although no distinguishing features are visible externally. In addition to their role in reproduction, the gonads are also nutrient storing organs, and are made up of two main type of cells: germ cells, and somatic cells called nutritive phagocytes. Regular sea urchins have five gonads, lying underneath the interambulacral regions of the test, while the irregular forms mostly have four, with the hindmost gonad being absent; heart urchins have three or two. Each gonad has a single duct rising from the upper pole to open at a gonopore lying in one of the genital plates surrounding the anus.
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55 pp. One of the most important aspects of hatchery rearing is obtaining and maintaining broodstock. Broodstock must be conditioned so to stimulate gonad development leading up to spawning and much research has been devoted to identifying the best diets and water quality requirements for broodstock. Once broodstock have been conditioned, spawning can be induced.
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The first phase of migration in Drosophila occurs when the pole cells move passively and infold into the midgut invagination. Active migration occurs through repellents and attractants. The expression of wunen in the endoderm repels the PGCs out. The expression of columbus and hedgehog attracts the PGCs to the mesodermal precursors of the gonad.
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Breeding biology is unknown, however all adults examined during mid March were at an early stage of gonad development. The smallest fish collected during this time, , indicates a possible breeding season of late winter or early spring. Galaxias brevvissimus is not believed to migrate to the sea or the estuary during its life cycle.
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The connective tissue and folds in the gonad gradually reduce as oogenesis progresses. In the maturity stage, the oocytes are mature and have reached their maximum size. Oocytes are present in all tubules in the lumen, and their peripheral nuclei are distinguishable. Connective tissue is absent, and the gonadal wall is very thin (3).
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Schedl Lab Protocol for gonad dissections In a C. elegans behavioral assay, analyzing the time course of paralysis provides information about the neuromuscular junction. Levamisole acts as an acetylcholine receptor agonist, which leads to muscle contraction. Continuing activation leads to paralysis. The time course of paralysis provides information about the acetylcholine receptors on the muscle.
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Two species are sold as fish bait. In most species the sexes are separate, but all the freshwater species are hermaphroditic. Nemerteans often have numerous temporary gonads (ovaries or testes), and build temporary gonoducts (ducts from which the ova or sperm are emitted), one per gonad, when the ova and sperm are ready. The eggs are generally fertilised externally.
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During a long period in the initial stages of its development, the Strombus pugilis larvae feed mainly on plankton. Studies indicate that some populations of Strombus pugilis may reproduce throughout the year.Cardenas, E.B., D. Aldana Aranda, and G. Martínez Olivares. (2005). Gonad development and reproductive pattern of the fighting conch Strombus pugilis (Lineé, 1758) (Gastropoda, Prosobranchia) from Campeche, Mexico.
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Once proper SOX9 levels are reached, the bipotential cells of the gonad begin to differentiate into Sertoli cells. Additionally, cells expressing TDF will continue to proliferate to form the primordial testis. While this constitutes the basic series of events, this brief review should be taken with caution since there are many more factors that influence sex differentiation.
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Bidder's organ is a spherical, brownish organ in most members of the family Bufonidae (true toads). The organ is located just in front of the kidney, or mesonephros. It is formed at the cranial tip of the male and female gonad during the larval stage. Its main function appears to be endocrine, taking part in regulating sex hormones.
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Xenoestrogen is not good for the health of the uterus. It reduces the flexibility of the uterine walls. Xenoestrogen makes the uterine walls thinner and fragile. When comparing fish from above a wastewater treatment plant and below a wastewater treatment plant, studies found disrupted ovarian and testicular histopathology, gonadal intersex, reduced gonad size, vitellogenin induction, and altered sex ratios.
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Although their exact pathways are not fully understood, they have been proven to be essential for the continued expression of SOX9 at the levels necessary for testes development. SOX9 and TDF are believed to be responsible for the cell- autonomous differentiation of supporting cell precursors in the gonads into Sertoli cells, the beginning of testes development. These initial Sertoli cells, in the center of the gonad, are hypothesized to be the starting point for a wave of FGF9 that spreads throughout the developing XY gonad, leading to further differentiation of Sertoli cells via the up-regulation of SOX9. SOX9 and TDF are also believed to be responsible for many of the later processes of testis development (such as Leydig cell differentiation, sex cord formation, and formation of testis-specific vasculature), although exact mechanisms remain unclear.
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The New Zealand scallop is a large industry and export product of New Zealand. The large white adductor muscle is eaten; sometimes, the orange and white gonad is eaten, as well. P. novaezelandiae is considered a fine food and can be expensive to purchase. Recreational and commercial fishing of this species is allowed at particular times of the year, the scallop season.
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Larvae of internal hatching could have gonad damage, which reduces fitness of those individuals. Internally hatched larvae also survived equally as well or even better than externally hatched worms. This means that worm bagging does not negatively influence the size or survival of the offspring. The destruction of the mother provides nutrients to the offspring, which is an efficient transfer of nutrients.
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The temperature in which the H. erectus dwells varies with the different latitudes. Temperature has an effect on gonad development, brood size, and juvenile development and survival. Many lined seahorses experience temperature fluctuations during the daily tide cycles, the different seasons of each year, and due to precipitation or runoff. Adults have the ability to migrate to deeper waters during cold seasons.
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Mature individuals can reach 2 cm in diameter, but rarely reach 1.5 cm. Clytia gregaria's translucent bell is saucer-shaped, with a diameter greater than its height. Positioned close to the bell margin are four radial canals with a white or yellowish elongated gonad in each. On the bell margin are up to 60 highly extensile tentacles of equal length (in mature individuals).
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Developing spermatocytes are still present at the periphery layer. a layer of connective tissue is present at the gonad wall The gonadal wall is observed to thicken, and folds are present inside of the wall. Spawning in brown sea cucumbers occurs throughout the summer months. Finally, in post spawning, large quantity of phagocytes is present both inside and outside of the follicles.
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Hen-feathering in cocks does not manifest itself unless the feathers are developed under the influx of sexual hormones. The effect on feathering is just the same both whether the hormone comes from the own testicles of the male or from an injection of testosterone.Roxas, H. A. 1926 Gonad cross-transplantation in Sebright and Leghorn fowls. J. Exptl. Zoöl. 46,63-119.
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Certain medical conditions can cause a chicken's left ovary to regress. In the absence of a functional left ovary, the dormant right sex organ may begin to grow; if the activated right gonad is an ovotestis or testes, it will begin secreting androgens. The hen does not completely change into a rooster, however. This transition is limited to making the bird phenotypically male.
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Without DHT, male external genitalia will not develop during embryo growth. Cells of urogenital ridges and underlying mesenchyme proliferate and form primary sex cords, which then undergo a series of mitotic division, under influence of TDF, develop into male gonad. Elongation of genital tubercle forms developing glans penis. As phallus elongates, it pulls forward urethral folds that surrounds urogenital sinus together.
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One of the most essential features of the ecology of E. baikalensis is the alteration of its mass inhabited areas during a year, as well as in day time. This is due to the need for various conditions for gonad maturation, reproduction, nourishing and protection from being consumed by planktivores. It is the Epischurella baikalensis which keeps Lake Baikal clean.
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Adult male and female medusa spawn daily, and can be entrained with controlled light conditions to spawn at specific times. The oocytes, eggs, embryos, and planulae of Clytia are easily visualized under a microscope and, much like those of popular model organisms like sea urchins, the zygotes of C. hemisphaerica are relatively large (around 200 um in diameter) and can be microinjected to form transgenic planulae, polyp colonies, and medusa. Clytia is also unique in that its gonads can function autonomously; a gonad separated from an adult medusa will undergo oocyte development and ovulation under the same entrained light cues as would a gonad still attached to a medusa. Clytia medusa that are produced from a single polyp colony are also genetically identical, presenting a huge advantage for gene function analysis as well as genome sequencing.
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'Nadgers' is one of many words with sexual innuendo which emerged in the 1950s and 1960s to evade strict BBC censorship. The etymology is uncertain, but possibly based on 'gonad'. When Rambling Syd Rumpo on Round the Horne asked "What shall we do with the drunken nurker?", the answer he gave was "Hit him in the 'nadgers' with the bosun's plunger...'til his 'bogles' dangle".
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In biology, Gonozooids are any of the reproductive individuals of Tunicates, Bryozoan, or Hydrozoan colonies that produce gametes . Gonozooids may play a role in labour division or in alternation of generations. A gonozooid typically has hardly any other function than reproduction, amounting to little more than a motile gonad. The production of gonozooids amounts to one aspect of certain classes of alternation of generations.
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Fewer than 300 small oocytes are produced by each gonad. Some of these are phagocytosed and others are supplied with yolks and grow in size before being spawned. A parasitic turbellarian Triloborhynchus psilastericola is often present in the coelom of the starfish and when the worm is approaching maturation, it moves into the pyloric caeca and at the same time loses all its cilia.
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The majority of DMRT1 protein is located in the testicular cord and Sertoli cells, with a small amount in the germ cells. This gene exhibits a gonad-specific and sexually dimorphic expression pattern, just like the related doublesex gene in fruit flies. Defective testicular development and XY feminization occur when this gene is hemizygous. Two copies of the DMRT1 gene are required for normal sexual development.
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Gonad, genitalia and digestive tract also receive branches. Phalangioidea have additional spiracles on the tibiae of the pedipalps and legs, thus helping in gas exchange in the long legs. They also provide a severed leg with oxygen, allowing it to continue twitching for some time: A leg of Opilio twitched for about 23 minutes, but stopped after about 40 seconds when the spiracles were sealed.
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The most common reason for high serum FSH concentration is in a female who is undergoing or has recently undergone menopause. High levels of FSH indicate that the normal restricting feedback from the gonad is absent, leading to an unrestricted pituitary FSH production. FSH may contribute to postmenopausal osteoporosis and cardiovascular disease. If high FSH levels occur during the reproductive years, it is abnormal.
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The outer (cytosolic) face of the rough endoplasmic reticulum is studded with ribosomes that are the sites of protein synthesis. The rough endoplasmic reticulum is especially prominent in cells such as hepatocytes. The smooth endoplasmic reticulum lacks ribosomes and functions in lipid synthesis but not metabolism, the production of steroid hormones, and detoxification. The smooth endoplasmic reticulum is especially abundant in mammalian liver and gonad cells.
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Thelenota ananas, a giant sea cucumber from the Indo-Pacific tropics Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian () species worldwide is about 1,717 with the greatest number being in the Asia Pacific region.
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Monogononta is a class of rotifers, found mostly in freshwater but also in soil and marine environments. They include both free-swimming and sessile forms. Monogononts generally have a reduced corona, and each individual has a single gonad, which gives the group its name. Males are generally smaller than females, and are produced only during certain times of the year, with females otherwise reproducing through parthenogenesis.
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111, 352-360 (1935) However, attempts to stop broodiness by the administration of several hormones have failed because this state, once evoked, requires time to revert. Prolactin injections inhibit the production of gonadotropin hormone, a hormone that stimulates ovarian follicles which is produced in the frontal lobe of hypophysis.Bates, R. W. y cols. The mechanism of the anti-gonad action of prolactin in adult pigeons. Amer.
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Mature females usually contain up to 42 eggs. The average is 4 eggs over 5 mm long. Mature black hagfish females often contain various sized groups of eggs—sometimes having three distinct size groups. Contained in a typical gonad might be: one group with eggs from 19 – 22 mm, another group with eggs ranging from 1 – 4 mm, and a third group of eggs less than 1mm long.
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First the external epithelium is formed, then the internal structures develop. After this gastrulation occurs by invagination followed by the development of a mouth. A relaxin-like peptide, previously referred to as “Gonad Stimulating Substance”, has also been found in this starfish. There is evidence that the peptide is involved in reproductive processes and functions via a G protein-coupled receptor, which supports its relatedness to vertebrate relaxins.
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Only strands of gonad tangled in the gut are eviscerated. The paired respiratory trees and cloaca also remain (although they may be expelled in other species) #The introvert changes from being firm and opaque to being soft and translucent. The body-wall muscles contract and the increased pressure forces coelomic fluid and viscera into the introvert. It enlarges like a balloon and soon ruptures, expelling the fluid and viscera.
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Riddle discovered that prolactin injections inhibited gonad growth in males and produced maternal behavior in females. His research demonstrated that prolactin and other hormones of the frontal lobe are disintegrated by the enzyme trypsin. His work also showed that growth is a synergistic response to the hormones prolactin and thyrotropin. He earned a degree in law in 1933 and was featured on the cover of TIME in January 1939.
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Differentiation of the gonads requires a tightly regulated cascade of genetic, molecular and morphogenic events. At the formation of the developed gonad, steroid production influences local and distant receptors for continued morphological and biochemical changes. This results in the appropriate phenotype corresponding to the karyotype (46,XX for females and 46,XY for males). Gonadal dysgenesis arises from the failure of signalling in this tightly regulated process during early foetal development.
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Drawing of reproductive system of Anostoma depressum viewed from apex of spire. ag. - accessory glands f - flagellum g - gonad r - seminal receptacle. Drawing of digestive tract of Anostoma depressum viewed from apex of spire. The description of the reproductive system of Ringicella ringens as described by Fischer (1869) applies in all essential details to Anostoma depressum with the exception of a penis retractor muscle attached to the vas deferens.
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Retinoic acid (RA) is an important factor that causes differentiation of primordial germ cells. In males, the mesonephros releases retinoic acid. RA then goes to the gonad causing an enzyme called CYP26B1 to be released by sertoli cells. CYP26B1 metabolizes RA, and because sertoli cells surround primordial germ cells (PGCs), PGCs never come into contact with RA, which results in a lack of proliferation of PGCs and no meiotic entry.
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PISRT1 (polled intersex syndrome regulated transcript 1) is a long non-coding RNA. It has been implicated in the polled intersex (PIS) mutation in goats. It has been shown not to be involved in sex determination in the rodent Ellobius lutescens and in dogs, and is unlikely to be involved in sex-specific gonad differentiation in mice. Polled Intersex Syndrome (PIS) is a disorder of sexual development seen in goats.
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Buster Gonad is a cartoon character in the British comic Viz. The strip involves the surreal adventures of "the boy with unfeasibly large testicles". During a storm, Buster's gonads were zapped by cosmic rays which enlarged them to an enormous size, so that he needs a wheelbarrow to carry them around. As a result, they are impossible to conceal and are therefore out on open display for everyone to see and marvel at.
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After the second molt the tail disappears and there is rapid growth in the intestine region. Female gonad development begins in the third stage juvenile with the esophagus measuring 28% body length and the stylet measuring 18µ. After the fourth molt female gonads are completely developed but the vulva and vagina are not visible until molting is complete. An adult female has an esophagus measuring 22% body length and a stylet of 22.5µ.
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Surf bream come downstream to river mouths during spawning season, where they spawn and the females lay planktonic eggs. These hatch after a few days, and the young remain in the estuaries. Like other species of sparid fish, the surf bream have a gonad termed the ovotestis that is made up of ovarian tissue dorsally and testicular tissue ventrally, separated by connective tissue. The species is protandrous – male fish become female after the spawning season.
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During development each gonad (ovary or testicle) descend from their starting point on the posterior abdominal wall (para-aortically) from the labioscrotal swellings near the kidneys, down the abdomen, and through the inguinal canals to reach the scrotum. Each testicle then descends through the abdominal wall into the scrotum, behind the processus vaginalis (which later obliterates). Thus lymphatic spread from a testicular tumour is to the para-aortic nodes first, and not the inguinal nodes.
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Temporary gonoducts (ducts from which the ova or sperm are emitted), one per gonad, are built when the ova and sperm are ready. The eggs are generally fertilised externally. Some species shed them into the water, some lay them in a burrow or tube, and some protect them by cocoons or gelatinous strings. Some bathypelagic (deep sea) species have internal fertilization, and some of these are viviparous, growing their embryos in the female's body.
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When complexed with the SF1 protein, TDF acts as a transcription factor that causes upregulation of other transcription factors, most importantly SOX9. Its expression causes the development of primary sex cords, which later develop into seminiferous tubules. These cords form in the central part of the yet-undifferentiated gonad, turning it into a testis. The now- induced Leydig cells of the testis then start secreting testosterone, while the Sertoli cells produce anti-Müllerian hormone.
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Aromatase, an estrogen-synthesizing enzyme which acts as a steroid hormone, plays a key role in sex determination in many non-mammalian vertebrates, including the Iberian ribbed newt. It is found in higher levels in the gonad–mesonephros complexes in ZW larvae than in their ZZ counterparts, although not in heat-treated ZW larvae. The increase occurs near the final stages of which their sex can be determined by temperature (stage 52).
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Cultured dark Tahiti pearls, one of the pearls is cut to expose the manmade nucleus bead The cultured pearls on the market today can be divided into two categories. The first category covers the beaded cultured pearls, including Akoya, South Sea, Tahiti and the large, modern freshwater pearl, the Edison pearl. These pearls are gonad-grown, and usually one pearl is grown at a time. This limits the number of pearls at a harvest period.
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PTMs become recognisable at 12 weeks gestation in humans, and 13.5 days post conception in mice. However, where they arise from is currently unclear. Previous studies suggested that PTMs originate from a group of cells called mesonephric cells, which migrate into the developing gonad from an adjacent area called the mesonephric primordia. It was thought that the mesonephric cells would then have one of three fates: becoming Leydig cells, vascular tissue or myoid cells.
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Paul Albert Ancel (21 September 1873 – 27 January 1961) was a French professor of medicine who worked on cytology, physiology, and embryology. He studied endocrine functions of the Leydig cells of the testes along with Paul Bouin. Ancel was born in Nancy from where he received a degree in medicine in 1899. He received a doctor of science in 1903 with a thesis on the hermaphroditic gonad of the snail Helix pomatia.
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Initial development of external genital is independent of androgens before indifferent gonads differentiate into testes. It occurs by week eight of gestation, as directed by a number of genes. External genitalia develop from mesenchymal cells underlying coelomic epithelium lining urogenital ridges on posterior wall of abdomen. Primordial germ cells (PGCs), precursors of gametes, migrate from egg sac into urogenital ridges, the site of gonad development in early embryonic development, by week six.
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Sharaf ad-Din depicting an operation for castration, c. 1466 Castration (also known as orchiectomy or orchidectomy) is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchidectomy (excision of both testicles), and chemical castration uses pharmaceutical drugs to deactivate the testes. Castration causes sterilization (preventing the castrated person or animal from reproducing); it also greatly reduces the production of certain hormones, such as testosterone.
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One exception is sleep apnea, which is present in around 70% of cases, but does not tend to resolve with successful treatment of growth hormone level. While hypertension is a complication of 40% of cases, it typically responds well to regular regimens of blood pressure medication. Diabetes that occurs with acromegaly is treated with the typical medications, but successful lowering of growth hormone levels often alleviates symptoms of diabetes. Hypogonadism without gonad destruction is reversible with treatment.
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An egg-layer, a typical adult female can lay 300,000 eggs in a single spawn. Although carp typically spawn in the spring, in response to rising water temperatures and rainfall, carp can spawn multiple times in a season. In commercial operations, spawning is often stimulated using a process called hypophysation, where lyophilized pituitary extract is injected into the fish. The pituitary extract contains gonadotropic hormones which stimulate gonad maturation and sex steroid production, ultimately promoting reproduction.
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Ovarian germ cell tumors (OGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad, which accounts for about 2.6% of all ovarian malignancies. There are four main types of OGCTs, namely dysgerminomas, yolk sac tumor, teratoma, and choriocarcinoma. Dygerminomas are Malignant germ cell tumor of ovary and particularly prominent in patients diagnosed with gonadal dysgenesis. OGCTs are relatively difficult to detect and diagnose at an early stage because of the nonspecific histological characteristics.
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Shed cuticle of female tardigrade, containing eggs Although some species are parthenogenic, both males and females are usually present, although females are frequently larger and more common. Both sexes have a single gonad located above the intestine. Two ducts run from the testes in males, opening through a single pore in front of the anus. In contrast, females have a single duct opening either just above the anus or directly into the rectum, which forms a cloaca.
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In gonochoristic fishes, the sex can be determined genetically, environmentally or by a combination of both. In fishes, primary sexual fate can be susceptible to alteration by hormones exposure and multiple environmental factors, such as population density, water pH, or temperature. Those conditions can affect the gonad development and differentiation, which can lead to sex reversal. In medaka fish, where sex reversal has been documented show a shared gene related to normal male development, the dmy gene.
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Scaphopods have separate sexes, and external fertilisation. They have a single gonad occupying much of the posterior part of the body, and shed their gametes into the water through the nephridium. Once fertilized, the eggs hatch into a free-living trochophore larva, which develops into a veliger larva that more closely resembles the adult, but lacks the extreme elongation of the adult body. The three-lobed foot originates prior to metamorphosis while the cephalic tentacles develop post metamorphosis.
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An Ophiothrix fragilis brittle star with missing arm segments from Póvoa de Varzim, Portugal Ophiuroids can readily regenerate lost arms or arm segments unless all arms are lost. Ophiuroids use this ability to escape predators, in a way similar to lizards which deliberately shed the distal part of their tails to confuse pursuers. Moreover, the Amphiuridae can regenerate gut and gonad fragments lost along with the arms. Discarded arms have not been shown to have the ability to regenerate.
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Phagocytes surround the inside and outside of the lumen. During the spawning stage, there is a decrease in the number of oocytes and an absence of gametes due to spawning. A layer of connective tissue is present at the gonad wall The gonadal wall is observed to thicken, and folds are present inside of the wall. Any of the remaining oocytes are either in maturity or oogenesis Lastly, in post spawning, oocytes observed have significantly decreased in volume.
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Males: The SRY gene when transcribed and processed produces SRY protein that binds to DNA and directs the development of the gonad into testes. Male development can only occur when the fetal testis secretes key hormones at a critical period in early gestation. The testes begin to secrete three hormones that influence the male internal and external genitalia: they secrete anti-müllerian hormone (AMH), testosterone, and dihydrotestosterone (DHT). Anti-müllerian hormone causes the paramesonephric ducts to regress.
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They then each extend their penis, which is armed with a sharp stylet, and push this through the body wall of the partner and transfer sperm by hypodermic injection. The gonad occupies most of the body interior, and the injection can be anywhere on the body wall. Reciprocal injections usually take place at the same time, especially in larger individuals. These sea slugs are able to transfer sperm in this way within two days of metamorphosis when only long.
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Studies have shown that the levels of KISS1 mRNA expressed in the hippocampus are proportional to less than half of the levels found in the hypothalamus. Despite this, it is suggested that expression of KISS1 is influenced by the gonad hormones similar to the hypothalamus. There is a high degree of expression of GPR54 in the hippocampus. The density of GPR54 is not discernable in pyramidal cells, but has high levels of expression in the granule cell layer.
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Their mating behavior has not been studied, but females are usually larger than males and more numerous (at a ratio of 1 male per 1.6 females). Since no specimens with intermediate gonad morphologies have been collected thus far, it is likely that they are not hermaphroditic as some other goby species are. They have also been observed sheltering in the tentacles of the hoplites corallimorph (Paracorynactis hoplites), with no apparent adverse effects from the stinging cells.
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A progonadotropin, or hypergonadotropin, also known as a gonad stimulant, is a type of drug which increases the secretion of one or both of the major gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This, in turn, results in increased function and maintenance of the gonads and increased gonadal steroidogenesis of sex hormones such as androgens, estrogens, and progestogens. Progonadotropins are the functional opposites of antigonadotropins. They have clinical applications in the treatment of hypogonadism and infertility.
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"Auricularia" larva (by Ernst Haeckel) Most sea cucumbers reproduce by releasing sperm and ova into the ocean water. Depending on conditions, one organism can produce thousands of gametes. Sea cucumbers are typically dioecious, with separate male and female individuals, but some species are protandric. The reproductive system consists of a single gonad, consisting of a cluster of tubules emptying into a single duct that opens on the upper surface of the animal, close to the tentacles.
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The medusae of hydrozoans are smaller than those of typical jellyfish, ranging from in diameter. Although most hydrozoans have a medusoid stage, this is not always free-living, and in many species, exists solely as a sexually reproducing bud on the surface of the hydroid colony. Sometimes, these medusoid buds may be so degenerated as to entirely lack tentacles or mouths, essentially consisting of an isolated gonad. The body consists of a dome-like umbrella ringed by tentacles.
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A set of "valve cells" connects the pharynx to the intestine, but how this valve operates is not understood. After digestion, the contents of the intestine are released via the rectum, as is the case with all other nematodes. No direct connection exists between the pharynx and the excretory canal, which functions in the release of liquid urine. Males have a single-lobed gonad, a vas deferens, and a tail specialized for mating, which incorporates spicules.
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Snake sperm morphology and function is highly influenced by their ability to find, interact with, and fertilize eggs. Snake species display extended copulations and higher gonad mass/body mass proportions in males than other reptilian taxonomic groups. Furthermore, their mating systems have a wide range of variability, depending on the temporal availability and predictability of the females. These factors influence sperm competition levels in both intense male-male combative species and those species that participate in prolonged mate searching.
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For example, Hemioniscus balani, a parasitic castrator of hermaphroditic barnacles, feeds on ovarian fluid, so that its host loses female reproductive ability but still can function as a male. This is a case of direct parasitic castration (feeding on host gonads). Indirect strategies are also seen such as diverting host energy from gonad development or secreting castrating hormones. The parasitic castration strategy is used by some larval trematode parasites of snails and some isopod and barnacle parasites of crustaceans.
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This copepod can cause lesions to the skin of the fish and damage to the underlying tissues. In the sprat, it burrows into the eye, causing the lens to become opaque, the retina to distort and buckle, and bleeding to occur. The fish's vision is reduced and it may be blinded in that eye. In the halfbeak, it usually attaches to the flanks, burying its head in the nearest accessible organ, usually the kidney, but sometimes the gonad.
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The whole is roughly cylindrical and has a swimming fin on the opposite side from the shell, with a small sucker on its edge. The gelatinous body is translucent, and the gut and its contents can be seen through the body wall. The retinas of the eyes are visible as two black spots. The visceral nucleus, which includes the liver, heart, gonad, sexual glands and kidneys, is a dark, stalked, triangular area protected by the shell, which also houses the gills.
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The body cavity has a separate compartment in each of the first three regions of the body, and extends into the tentacles. The opisthoma has a coelomic chamber in each of its five to 23 segments, separated by septa. The worms have a complex closed circulatory system and a well-developed nervous system, but as adults, siboglinids completely lack a mouth, gut, and anus. Siboglinids are dioecious, with one gonad on each side of the trunk, within the body cavity.
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These embryonic structures are on either side; the pronephros, the mesonephros and the metanephros of the kidney, and the Wolffian and Müllerian ducts of the sex organ. The pronephros disappears very early; the structural elements of the mesonephros mostly degenerate, but the gonad is developed in their place, with which the Wolffian duct remains as the duct in males, and the Müllerian as that of the female. Some of the tubules of the mesonephros form part of the permanent kidney.
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Cryptasterina hystera is a hermaphrodite; the gonads can produce both sperm and eggs and are known as ovotestes. Fertilization of the eggs take place when sperm liberated by another starfish is drawn into the gonad through the gonoduct. The eggs are few in number and have large yolks and are retained inside the starfish which is viviparous. The brachiolaria larvae that develop inside the gonads "swim" in the fluid there and are eventually released into the sea through the gonopore as juvenile starfish.
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Eugenides addresses how difficult it was for humans to devise a "universal classification for sex". Through Cal, scholar Angela Pattatucci Aragon stated, Eugenides opines that the 1876 system devised by Edwin Klebs that used gonad tissue to determine sex provides the most accurate answer. According to intersex activist and academic Morgan Holmes, Eugenides posits that a person's sexual attraction determines his or her gender. Cal's wish to become male because he desires females demonstrates a link between gender identity and sexuality.
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The testes begin as an immigration of primordial germ cells into testicular cords along the gonadal ridge in the abdomen of the early embryo. The interaction of several male genes organizes this developing gonad into a testis rather than an ovary by the second month of gestation. During the third to fifth months, the cells in the testes differentiate into testosterone-producing Leydig cells, and anti-Müllerian hormone-producing Sertoli cells. The germ cells in this environment become fetal spermatogonia.
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P elements are a family of transposons that recently proliferated within the genome of Drosophila melanogaster. The P elements have an extremely high transposition rate and induce sterility and abnormal gonad development in D. melanogaster (Johnson, 2). The flies thus developed a maternally inherited technique for combating the invasive DNA and silencing the transposons, now known as P cytotype. P cytotype detects DNA sequences in areas of telomeric heterochromatin and silences those sequences when they are found elsewhere in the genome.
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Behaviorally, metabolic rate can be lowered through reduced locomotion, feeding, courtship, and mating. Physiologically, metabolic rate can be lowered through reduced growth, digestion, gonad development, and ventilation efforts. And biochemically, metabolic rate can be further lowered below standard metabolic rate through reduced gluconeogenesis, protein synthesis and degradation rates, and ion pumping across cellular membranes. Reductions in these processes lower ATP use rates, but it remains unclear whether metabolic suppression is induced through an initial reduction in ATP use or ATP supply.
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During mammalian development, the gonads are at first capable of becoming either ovaries or testes. In humans, starting at about week 4, the gonadal rudiments are present within the intermediate mesoderm adjacent to the developing kidneys. At about week 6, epithelial sex cords develop within the forming testes and incorporate the germ cells as they migrate into the gonads. In males, certain Y chromosome genes, particularly SRY, control development of the male phenotype, including conversion of the early bipotential gonad into testes.
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The cause of the condition is often unclear. There are cases where abnormalities in the FSH-receptor have been reported. Apparently either the germ cells do not form or interact with the gonadal ridge or undergo accelerated atresia so that at the end of childhood only a streak gonad is present, unable to induce pubertal changes. As girls' ovaries produce no important body changes before puberty, there is usually no suspicion of a defect of the reproductive system until puberty fails to occur.
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In his De Mulierum Organis Generatione Inservientibus (1672), de Graaf provided the first thorough description of the female gonad and established that it produced the ovum. De Graaf used the terminology vesicle or egg (ovum) for what now called the ovarian follicle. Because the fluid-filled ovarian vesicles had been observed previously by others, including Andreas Vesalius and Falloppio, De Graaf did not claim their discovery. He noted that he was not the first to describe them, but to describe their development.
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The eruption of Kelud Volcano on February 13, 2014, which released a huge amount of volcanic dust and nearly covered the whole of Java island possibly changed the fish. As a result, the exposure of fish to the volcanic dust which naturally dissolves on the water body, affected and caused change on the histological structure of gills and intestine, but did not have an effect on the histological structure of eyes, liver and gonad of the wader pari fish, respectively.
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Instead of being smooth, their retina is composed of tiny cups, acting like parabolic mirrors. Because of the murky waters, the cones in their eyes have adapted to see only red light. The cups are made of four layers of light reflecting proteins, funneling red light to areas of cones, intensifying its brightness 10-fold, while the rods are hit by light from other wavelengths.Elephant-Nosed Fish Has Funky Eyes, Too Only a single gonad is present, located on the left side of their body.
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C. kynthia from southwestern Australia and C. wurlerra from New South Wales were described in 2008 based mainly on colour, their tentacles and details of their gonad shape, but these can be variable in Chrysaora. As a result, they were tentatively considered as nomina dubia in 2010 (however, Chrysaora of southwestern Australia and New South Wales were not assigned to other species). This view, with C. pentastoma as the only currently recognized species in Australia, is followed by the World Register of Marine Species.
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Many genes have been implicated in the disorders of TDS, with genome wide association studies (GWAS) regularly identifying new gene variants that play a role in abnormal testes development. Some of these are specific to certain disorders, and some are part of a 'risk factor network' that connect TGCC, hypospadias, cryptorchidism, poor semen quality. The majority of these genes are involved in fetal gonad development. Mutations in androgen receptor genes are highly implicated, as these are involved in penile development, testes descent, and testes development.
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The two spawning seasons for Siganus sutor are January/February and May/June.The presence of these seasons is determined by three factors: (1) temporal changes in the condition factor and relative weight of the gonads, (2) the progression of peaks of maturity stages with seasonal presence of spent fish in the samples, and (3) the seasonal appearance of juveniles.[Ntiba, M. J.; Jaccarini, V. (1990). "Gonad maturation and spawning times of Siganus sutor off the Kenya coast: evidence for definite spawning seasons in a tropical fish".
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Sea cucumbers are leathery echinoderms with elongated bodies which contain a single, branched gonad. They are found on the sea floor worldwide, and occur in great numbers on the deep sea floor where they often make up the majority of the animal biomass. They feed on plankton and decaying organic debris found at the sea bottom, catching food that flows by with their open tentacles or sifting through bottom sediments. Like sea urchins, most sea cucumbers reproduce by releasing sperm and ova into the ocean water.
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Chicken primordial germ cells are initially specified in the area pellucida (a one-cell thick layer of epiblast lying above the sub-germinal space). Following the formation of the primitive streak, the germ cells are carried to the germinal crescent region. Unlike most model organisms where germ cell migration is predominantly via the gut epithelium, chicken PGCs migrate through the embryonic vascular epithelium. Once they have exited the capillary vessels, the final stage of migration is along the dorsal mesentery to the developing gonad.
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There, she worked with molecular biologist David Hirsh who was studying the model organism Caenorhabditis elegans. Kimble then moved to the MRC Laboratory of Molecular Biology, where she spent four years as a postdoctoral fellow working with Sir John Sulston on the control of organogenesis. During the course of her work, Kimble found a special somatic cell at the tip of the gonad which tells nearby germ cells - reproductive cells - how to divide. When she destroyed the distal tip cell, germ cells stopped dividing.
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The sac-like ovotestis extends over the half of the right side of the visceral hump and is not separated into follicles; oocytes are located more in the exterior part of the gonad and the spermatocytes are positioned more in the centre. Sperm heads are short. Approximately 10 yolky oocytes were noted in the examined specimen. Anterior to the ovotestis there is a small receptaculum seminis containing sperm cells oriented with their heads to the wall, as well as a sac-like ampulla filled with unoriented autosperm.
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Koopman's early work with Anne McLaren spawned an interest in the regulation of the germ cells during fetal development—cells that later become sperm or oocytes. His group discovered that the vitamin A metabolite retinoic acid stimulates germ cells to enter meiosis, a critical step in the formation of gametes. They also demonstrated that the developmental signaling molecule Nodal and its receptor Cripto regulate male germ cell pluripotency in the fetal gonad, opening the way for new non-invasive diagnostics and targeted additional therapies for testicular cancers.
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46,XY gonadal dysgenesis is characteristic of male hypogonadism with karyotype 46,XY. In embryogenesis, the development of the male gonads is controlled by the testis determining factor located on the sex-determining region of the Y chromosome (SRY). The male gonad is dependent on SRY and the signalling pathways initiated to several other genes to facilitate testis development. The aetiology of 46,XY gonadal dysgenesis can be caused by mutations in the genes involved in testis development such as SRY, SOX9, WT1, SF1, and DHH.
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Adult male alt=Drawing of a male octopus with one large arm ending in the sexual apparatus Octopuses are gonochoric and have a single, posteriorly-located gonad which is associated with the coelom. The testis in males and the ovary in females bulges into the gonocoel and the gametes are released here. The gonocoel is connected by the gonoduct to the mantle cavity, which it enters at the gonopore. An optic gland creates hormones that cause the octopus to mature and age and stimulate gamete production.
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Splicing factor 1 also known as zinc finger protein 162 (ZFM162) is a protein that in humans is encoded by the SF1 gene. Splicing factor SF1 is involved in the ATP-dependent formation of the spliceosome complex. SF1 gene is necessary to make the bipotential gonad ; but while SF1 levels decline in the genital ridge of XX mouse embryos, the SF1 gene stays on the developing testes. SF 1 (transcription factor) appears to be active in masculining both the Leydig cells and Sertoli cells.
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Since the gonad tissue develops into testes rather than ovaries, they are thus unable to create ova but may be able to create sperm. Male fertility can still be possible if viable sperm is present in the testes and is able to be extracted. In general, individuals with 5-ARD are capable of producing viable sperm. Although the external genitalia can sometimes be completely female, the vagina consists of only the lower two-thirds of a normal vagina, creating a blind- ending vaginal pouch.
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Firoloida desmarestia has a proboscis, a long, transparent cylindrical body and a short, ventral tail. It has a large, rounded swimming fin, situated towards the front of the mollusc, and the opaque visceral nucleus, a mass which includes the liver, heart, gonad, sexual glands and kidneys, at the rear. Males have a sucker on the front edge of the fin, large tentacles in front of the eyes, and a tail filament, while females lack the sucker and tentacles, and have a string of eggs trailing behind them.
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Definitive hematopoiesis then occurs later in the aorta-gonad-mesonephros (AGM), a region of embryonic mesoderm that develops into the ventral wall of the dorsal aorta, at E10.5 in mice and 4wpc (4 weeks post-conception) in humans. New HSCs either enter the aortic circulation or remain within the endothelium. While Notch 1 has been found to stimulate aortic HSC production, Runx1 overexpression in the zebrafish mutant mindbomb that lacks Notch signaling rescues HSC production, suggesting Runx1 is downstream of Notch1. Hedgehog signaling is also required for HSC production in the AGM.
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Huang, Tzou, and Sternberg discovered that lin-15 encodes 2 transcripts that do not overlap and are transcribed in the same direction. They were able to analyze what role lin-15 plays in the signaling pathway and found that lin-15 acts upstream and parallel to the inductive signal of let-23. “A gonad-derived survival signal for vulval precursor cells in two nematode species”(1998) Felix and Sternberg discovered that there is a survival signal that prevents cell death in vulval precursor cells in T.aceti and Halicephalobus sp.
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Animation of the migration of spermatozoa from their origin as germ cells to their exit from the vas deferens. A.) Blood vessels; B.) Head of epididymis; C.) Efferent ductules; D.) Seminiferous tubules; E.) Parietal lamina of tunica vaginalis; F.) Visceral lamina of tunica vaginalis; G.) Cavity of tunica vaginalis; H.) Tunica albuginea; I.) Lobule of testis; J.) Tail of epididymis; K.) Body of epididymis; L.) Mediastinum; M.) Vas deferens. Testicle or testis (plural testes) is the male reproductive gland or gonad in all animals, including humans. It is homologous to the female ovary.
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At first they fed on food particles in the gastrovascular cavity of the jellyfish but after 11 days they developed parasitic habits and began to feed on their hosts' gonads, moving on later to other tissues. One anemone larva was able to consume a gonad completely in two days. Thirty-one days after becoming parasitic they had developed into juvenile sea anemones with an adult body plan. At this stage they detached themselves from their hosts and dropped to the sea floor where they started to live independently.
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Genital reconstructive surgery was pioneered between 1930 and 1960 by urologist Hugh Hampton Young and other surgeons at Johns Hopkins Hospital in Baltimore and other major university centers. Understanding of intersex conditions was relatively primitive, based on identifying the type of gonad(s) by palpation or by surgery. Since ability to determine even the type of gonads in infancy was limited, sex of assignment and rearing were determined mainly by the appearance of the external genitalia. Most of Young's intersex patients were adults willingly seeking his help with physical problems of genital function.
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Practically the whole body, except for the last pair of legs, is made up of just the segments that are homologous to the head region in arthropods. All adult tardigrades of the same species have the same number of cells (see eutely). Some species have as many as 40,000 cells in each adult, while others have far fewer.Kinchin, Ian M. (1994) The Biology of Tardigrades, Ashgate Publishing The body cavity consists of a haemocoel, but the only place where a true coelom can be found is around the gonad.
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After spawning the animals undergo period of recovery of the gonad before they spawn again. Fertilization of the gametes is external and either sperm or oocytes can be released into the water column first. Since the larval stage of Pecten maximus is relatively long, up to a month, the potential for dispersal is quite high, even smaller adults can use the byssus to drift too. However, in at least some populations, genetic studies show that there is little contribution from more distant populations and that these populations probably sustain themselves.
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Thus, the knockout model shows that loss of the DMRT1 gene is associated with incomplete germ cell development leading to infertility, abnormal testicular formation, and/or feminization of the affected individual. Induced knockout of DMRT1 in adult male mice has been found to cause transdifferentiation of somatic cells in the testis to the equivalent cell types that would ordinarily be found in the ovary. Conversely, conditional expression of DMRT1 in the gonad of female mice caused the apparent transdifferentiation of ovarian somatic (granulosa) cells to the equivalent cell type (Sertoli) ordinarily found in males.
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Sex reversal is a biological process whereby the pathway directed towards the already determined-sex fate is flipped towards the opposite sex, creating a discordance between the primary sex fate and the sex phenotype expressed. The process of sex reversal occurs during embryonic development or before gonad differentiation. In GSD species sex reversal means that the sexual phenotype is discordant with the genetic/chromosomal sex. In TSD species sex reversal means that the temperature/conditions that usually trigger the differentiation towards one sexual phenotype are producing the opposite sexual phenotype.
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The principal circulatory organ is the animal's heart which is located within a pericardial sack on the animal's left side near its head. The heart consists of a single (morphologically left) auricle, a single large and muscular ventricle, and the muscular but much smaller bulbous aorta below it which joins the posterior and anterior aortae. The posterior aorta opens into the visceral sinus, delivering blood to the gonad and digestive gland; the anterior aorta sends blood forward into the buccal mass. The ctenidium contains blood spaces and receives oxygen.
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Among his advances was the tubed pedicle graft, which maintained a flesh connection from the donor site until the graft established its own blood flow. Gillies' assistant, Archibald McIndoe, carried on the work into the Second World War as reconstructive surgery. In 1962, the first successful replantation surgery was performed – re-attaching a severed limb and restoring (limited) function and feeling. Transplant of a single gonad (testis) from a living donor was carried out in early July 1926 in Zaječar, Serbia, by a Russian émigré surgeon Dr. Peter Vasil'evič Kolesnikov.
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Nuclei from Mikimoto Pearl Island, Toba, Japan Cultured pearls are the response of the shell to a tissue implant. A tiny piece of mantle tissue (called a graft) from a donor shell is transplanted into a recipient shell, causing a pearl sac to form into which the tissue precipitates calcium carbonate. There are a number of methods for producing cultured pearls: using freshwater or seawater shells, transplanting the graft into the mantle or into the gonad, and adding a spherical bead as a nucleus. Most saltwater cultured pearls are grown with beads.
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Gonadal dysgenesis is classified as any congenital developmental disorder of the reproductive system in the male or female. It is the atypical development of the gonads in an embryo, with reproductive tissue replaced with functionless, fibrous tissue, termed streak gonads. Streak gonads are a form of aplasia, resulting in hormonal failure that manifests as sexual infantism and infertility, with no initiation of puberty and secondary sex characteristics. Gonadal development is a genetically controlled process by the chromosomal sex (XX or XY) which directs the formation of the gonad (ovary or testis).
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Mixed gonadal dysgenesis, also known as X0/XY mosaicism or partial gonadal dysgenesis is a sex development disorder associated with sex chromosome aneuploidy and mosaicism of the Y chromosome. Mixed gonadal dysgenesis is the presence of two or more germ line cells. The degree of development of the male reproductive tract is determined by the ratio of germ line cells expressing the XY genotype. Manifestations of mixed gonadal dysgenesis are highly variable with asymmetry in gonadal development of testis and streak gonad, accounted for by the percentage of cells expressing XY genotype.
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Yossi Loya and Kazuhiko Sakai, "Bidirectional sex change in mushroom stony corals", Proceedings of the Royal Society B, 22 October 2008 Chickens can sometimes undergo natural sex changes. Normally, female chickens have just one functional ovary, on their left side. Although two sex organs are present during the embryonic stages of all birds, once a chicken's female hormones come into effect, it typically develops only the left ovary. The right gonad, which has yet to be defined as an ovary, testes, or both (called an ovotestis), typically remains dormant.
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Most pearls are now obtained from cultured shells where an irritant substance has been purposefully introduced to induce the formation of a pearl. A "mabe" (irregular) pearl can be grown by the insertion of an implant, usually made of plastic, under a flap of the mantle and next to the mother-of-pearl interior of the shell. A more difficult procedure is the grafting of a piece of oyster mantle into the gonad of an adult specimen together with the insertion of a shell bead nucleus. This produces a superior, spherical pearl.
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The single gonad is located in front of the heart, and releases gametes through a pair of pores just in front of those used for excretion. The underside of the gumboot chiton, Cryptochiton stelleri, showing the foot in the center, surrounded by the gills and mantle: The mouth is visible to the left in this image. The mouth is located on the underside of the animal, and contains a tongue-like structure called a radula, which has numerous rows of 17 teeth each. The teeth are coated with magnetite, a hard ferric/ferrous oxide mineral.
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In vertebrates, rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually forms the supporting axis of the body and is then called the spine or vertebral column. Rachis can also mean the central shaft of pennaceous feathers. In the gonad of the invertebrate nematode C. elegans, a rachis is the central cell-free core or axis of the gonadal arm of both adult males and hermaphrodites where the germ cells have achieved pachytene and are attached to the walls of the gonadal tube.
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It has since been shown that the spawning of chiton is usually synchronous but not necessarily correlated with any particular stage of the lunar or solar cycle. Generally chitons have separate sexes and sperm and eggs are spawned through a simple gonad near the posterior end of the foot. Chitons do not have a free swimming larval stage so distribution of the organism is not particularly great. Once the egg has been released through the anus it moves through currents into plankton where it hatches after about 2 days.
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There may be a pheromone that alerts it to the fact that the testes are ripe and causes it to change its behaviour. As different species of starfish breed at different times of year, Orchitophrya stellarum may move from one species to another in accordance with their reproductive cycles. In the Atlantic Ocean, it may alternate between parasitising Asterias forbesi and Asterias rubens during the spring and summer and the winter host may be Leptasterias spp.. The ciliate has been found in the testes of all these species. When inside the gonad, it phagocytoses the sperm thus rendering the starfish infertile.
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They are hermaphroditic and have distinct tongue-shaped gonads which are red or orange in colour for the female gonad and white for the male. It is estimated that a three-year old scallop releases 15 - 21 million oocytes per emission. There appear to be two spawnings in many parts of the range, normally there is a partial one in the Spring and a full one in late August, however younger scallops have a single spawning event in the late summer. In some areas this pattern is reversed and the major spawning is in the Spring.
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One of the functions of PGC migration is to allow them to reach the gonad, where they will go on to form sperm or oocytes. However, an additional function that this migration is thought to serve is as quality control for PGCs. Migration occurs early in gametogenesis, but PGCs could contain defects that could have a negative impact on later development - genetic mutations may be acquired because of proliferation in the blastocyst. This is done via a negative selection process – PGCs that are unable to complete migration are removed and those that are able to correctly respond to migration cues are preferred.
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With the vast knowledge about in-vivo PGC specification collected over the last few decades, several attempts to generate in-vitro PGCs from post-implantation epiblast were made. Various groups were able to successfully generate PGC-like cells, cultured in the presence of BMP4 and various cytokines. The efficiency of this process was later enhanced by the addition of stem cell factor (SCF), epidermal growth factor (EGF), leukaemia inhibitory factor (LIF) and BMP8B. PGC-like cells generated using this method can be transplanted into a gonad, where the differentiate, and are able to give viable gametes and offspring in vivo.
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During gestation, the cells of the primordial gonad that lie along the urogenital ridge are in a bipotential state, meaning they possess the ability to become either male cells (Sertoli and Leydig cells) or female cells (follicle cells and theca cells). TDF initiates testis differentiation by activating male-specific transcription factors that allow these bipotential cells to differentiate and proliferate. TDF accomplishes this by upregulating SOX9, a transcription factor with a DNA-binding site very similar to TDF's. SOX9 leads to the upregulation of fibroblast growth factor 9 (Fgf9), which in turn leads to further upregulation of SOX9.
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In either case, females which change sex to males are larger and often prove to be a good example of dimorphism. In other cases with fish, males will go through noticeable changes in body size, and females will go through morphological changes that can only be seen inside of the body. For example, in sockeye salmon, males develop larger body size at maturity, including an increase in body depth, hump height, and snout length. Females experience minor changes in snout length, but the most noticeable difference is the huge increase in gonad size, which accounts for about 25% of body mass.
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Helicoverpa zea nudivirus 2 (HzNV-2, Hz-2V, gonad specific virus [GSV], or Heliothis zea nudivirus 2) is an enveloped, rod-shaped, nonoccluded, double stranded DNA (dsDNA) sexually transmitted virus whose natural host is the corn earworm moth. At about 440 by 90 nm, it is the causative agent of the only sexually transmitted viral disease of any insect. It was originally identified in a colony of corn earworm moths established and maintained in Stoneville, Mississippi, U.S. and was found to be responsible for the sterility of those infected. The virus does not always cause sterility, though.
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In children with precocious puberty of pituitary or central origin, LH and FSH levels may be in the reproductive range instead of the low levels typical for their age. During the reproductive years, relatively elevated LH is frequently seen in patients with polycystic ovary syndrome; however, it would be unusual for them to have LH levels outside of the normal reproductive range. Persistently high LH levels are indicative of situations where the normal restricting feedback from the gonad is absent, leading to a pituitary production of both LH and FSH. While this is typical in menopause, it is abnormal in the reproductive years.
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In animals, the behavioral effects of gonad removal differ along lines of species and not sex, i.e. there are species where mating behavior ceases if the gonads are removed and other species where it does not cease, but removal of ovaries in females halt mating behavior in all of the same nonhuman animals in which male castration halts mating behavior. Therefore, some scientists argue that the notion that castration/spaying would drastically reduce sex drive in human males but not in human females is zoologically nonsensical, citing that humans belong to the animal kingdom.Robert Aunger, Valerie Curtis (2015)"Gaining Control: How human behavior evolved"(2015).
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Spawning can be induced using several methods: thermal stimulation involves increasing and decreasing water temperatures rapidly, dry treatment involves leaving the sandfish out of the water for 30–45 minutes before being returned to the tanks, and the food stimulant method involves providing a highly concentrated amount of algae to the water to overfeed the sandfish. Gonad extraction is also an option but requires the dissection of the animal. It is common in most aquaculture facilities to use a combination of the listed methods, in order to ensure spawning. The sandfish larvae are closely monitored in order to ensure survival, as they are temperamental and require specific conditions for success.
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In humans, starting at about week 4 the gonadal rudiments are present within the intermediate mesoderm adjacent to the developing kidneys. At about week 6, sex cords develop within the forming testes. These are made up of early Sertoli cells that surround and nurture the germ cells that migrate into the gonads shortly before sex determination begins. In males, the sex-specific gene SRY that is found on the Y-chromosome initiates sex determination by downstream regulation of sex-determining factors, (such as GATA4, SOX9 and AMH), which leads to development of the male phenotype, including directing development of the early bipotential gonad down the male path of development.
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Tahitian pearl sizes in different colors The culturing process of a Tahitian pearl involves a grafter, who inserts a bead made from a mollusk shell into the gonad, or reproductive organ, of the mature Pinctada margaritifera mollusk. It takes two years for an oyster to mature enough to begin producing pearls. Inserted with the bead is a piece of mantle tissue from a donor mollusk, which influences the color of the pearl being produced and provides epithelial cells to ensure that the oyster produces nacre around the nucleus. The materials used in the process are organic, to decrease the probability of the oyster rejecting the nucleus.
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Many species of Talpid moles exhibit peniform clitorises that are tunneled by the urethra and are found to have erectile tissue, most notably species from the Talpa genus found in Europe. Unique to this clade are the presence of ovotestes, wherein the female ovary also is mostly made up of sterile testicular tissue that secretes testosterone with only a small portion of the gonad containing ovarian tissue. Genetic studies have revealed that females have an XX genotype and do not have any translocated Y-linked genes. Detailed developmental studies of Talpa occidentalis have revealed that the female gonads develop in a "testis-like pattern".
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Even in conditions where a given species will develop ovaries and spawn in captivity, use of eyestalk ablation increases total egg production and increases the percentage of females in a given population that will participate in reproduction. Once females have been subjected to eyestalk ablation, complete ovarian development often ensues within as little as 3 to 10 days. The practice was a major development for the commercialisation of shrimp farming in the 1970s and 80s since it enabled reliable production. The most commonly accepted theory of why eye ablation reduces this inhibition is that a gonad inhibitory hormone (GIH) is produced in the neurosecretory complexes in the eyestalk.
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The third CGI of TCF21 contains a promoter that directs transcription of TARID (a lncRNA) in antisense orientation to TCF21. TARID then induces TET protein-dependent DNA demethylation, thus activating TCF21 transcription. This mechanism is regulated by the binding of TARID to the TCF21 promoter, which recruits GADD45A/TDG to direct BER for demethylation. TCF21 encodes a transcription factor of the basic helix-loop-helix (bHLH) family, which manages cell-fate specification, commitment and differentiation in various cell lineages during development. The TCF21 product is mesoderm- specific and expressed in embryonic epicardium, mesenchyme-derived tissues of lung, gut, gonad, and both mesenchymal and glomerular epithelial cells in the kidney.
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TBT has been shown to harm many marine organisms, specifically oysters and mollusks. Extremely low concentrations of tributyltin moiety (TBT) causes defective shell growth in the oyster Crassostrea gigas (at a concentration of 20 ng/l) and development of male characteristics in female genitalia in the dog whelk Nucella lapillus (where changes in gonad characteristics are initiated at 1 ng/l). The international maritime community has phased out the use of organtin-based coatings. This phase-out of toxic biocides in marine coatings posed a severe problem for the shipping industry; it presents a major challenge for the producers of coatings to develop alternative technologies.
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Infection and graft-versus-host disease are major complications of allogeneic HSCT. In order to harvest stem cells from the circulating peripheral blood, blood donors are injected with a cytokine, such as granulocyte-colony stimulating factor (G-CSF), that induces cells to leave the bone marrow and circulate in the blood vessels. In mammalian embryology, the first definitive Hematopoietic stem cells are detected in the AGM (aorta- gonad-mesonephros), and then massively expanded in the fetal liver prior to colonising the bone marrow before birth. Hematopoietic stem cell transplantation remains a dangerous procedure with many possible complications; it is reserved for patients with life-threatening diseases.
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An impressive improvement in quality has taken place in the last ten years when the former rice grain-shaped pebbles are compared with the near round pearls of today. In the last two years large near perfect round bead nucleated pearls up to 15mm in diameter have been produced with metallic luster. The nucleus bead in a beaded cultured pearl is generally a polished sphere made from freshwater mussel shell. Along with a small piece of mantle tissue from another mollusk (donor shell) to serve as a catalyst for the pearl sac, it is surgically implanted into the gonad (reproductive organ) of a saltwater mollusk.
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During the process of molting, old outer layers of an animal are shed to allow for new growth to occur. This molting process is an important element for the animal to become sexually developed as well, and it was found to be an important process for the S. ocreata. Wrinn, K., & Uetz, G. (2007). Impacts of leg loss and regeneration on body condition, growth, and development time in the wolf spider Schizocosa ocreata. Canadian Journal of Zoology, 85 (7), 823-831 DOI: 10.1139/Z07-063 In addition, the process of molting, gonad development, and reproductive timing in females is all impacted by the female spiders’ feeding history.
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Following a summary of the prior, Fausto-Sterling shows her points on the gender development theories by noting how XY and XX chromosomes stay identical up until the 6th week of development in the womb. During these six weeks, the XY/XX embryos develop an indifferent gonad, an extra layer that isn't affected by the chromosome embryo due to their indistinguishable similarity at the time. This external process develops in a similar manner to the various male and female reproductive organs that later develop within the body. By the end of the first month and a half, all embryos would've developed, regardless of gender.
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Attainment of sexual maturity in Tarebia granifera is generally indicated by the size of the smallest snail observed to give birth rather than a histological assessment of the development of the gonad and associated reproductive structures. Appleton & Nadasan (2002) estimated onset of maturity at 10–12 mm shell height but unpublished data suggest a height closer to 8 mm in line with other published studies. Tucker Abbott (1952) estimated sexual maturity at between 5.5 and 8.0 mm at different stations over a short stretch of river in Florida. Chaniotis et al. (1980) gave a similar estimate of 6.0–7.0 mm from a cohort of laboratory-bred snails in Puerto Rico.
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The basic anatomy of C. elegans includes a mouth, pharynx, intestine, gonad, and collagenous cuticle. Like all nematodes, they have neither a circulatory nor a respiratory system. The four bands of muscles that run the length of the body are connected to a neural system that allows the muscles to move the animal's body only as dorsal bending or ventral bending, but not left or right, except for the head, where the four muscle quadrants are wired independently from one another. When a wave of dorsal/ventral muscle contractions proceeds from the back to the front of the animal, the animal is propelled backwards.
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The basic structure of the reproductive tract is similar in both sexes, with a mesodermal gonoduct (sperm duct or oviduct) emerging from both sides of the U-shaped gonad (testis or ovary). The two gonoducts fuse into a single duct, which leads into a cuticle-lined duct derived from the ectoderm into the open through an organ (penis in males or ovipositor in females) that can be everted through a combination of muscles and hemolymph pressure. These eversible organs play an important role in determining taxonomic relationships. The penis is often complex, consisting of a long shaft and a shorter glans at the end, which is often equipped with various projections such as spines.
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In 2002, Sergio recruited new members to reform the band: Charly and Lute on guitars, Tano on bass, and Tati on drums (later replaced by Nikito). While only Charly remained on guitar, and tension grew between the three remaining members, more new members were brought in: Juan Gonad on bass and Dany on drums. In 2004, the new lineup recorded a CD called Sentimiento Inexplicable at Fuera del Túnel studios. The disc included 10 songs, including one Alerta Roja cover (Juventud Perdida), one cover of a Cockney Rejects song in Spanish (Guerra en la popular), and a newly recorded version of a 1983 song, Desaparecido, dating from the era of Los Desalmados, the band preceding Comando Suicida.
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The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of the adult are preceded by a set of structures that are purely embryonic and that, with the exception of the ducts, disappear almost entirely before the end of fetal life. These embryonic structures are on either side: the pronephros, the mesonephros and the metanephros of the kidney, and the Wolffian and Müllerian ducts of the sex organ. The pronephros disappears very early; the structural elements of the mesonephros mostly degenerate, but the gonad is developed in their place, with which the Wolffian duct remains as the duct in males, and the Müllerian as that of the female.
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Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to a solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth. Most jellyfish do not have specialized systems for osmoregulation, respiration and circulation, and do not have a central nervous system.
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Kraepelin had experimented with hypnosis but found it wanting, and disapproved of Freud's and Jung's introduction, based on no evidence, of psychogenic assumptions to the interpretation and treatment of mental illness. He argued that, without knowing the underlying cause of dementia praecox or manic-depressive illness, there could be no disease-specific treatment, and recommended the use of long baths and the occasional use of drugs such as opiates and barbiturates for the amelioration of distress, as well as occupational activities, where suitable, for all institutionalized patients. Based on his theory that dementia praecox is the product of autointoxication emanating from the sex glands, Kraepelin experimented, without success, with injections of thyroid, gonad and other glandular extracts.
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Simon Donald drawing Sid the Sexist in a copy of his book, Him off the Viz, November 2010 Many Viz characters have featured in long-running strips, becoming well known in their own right, including spin-off cartoons. Characters often have rhyming or humorous taglines, such as Roger Mellie, the Man on the Telly; Nobby's Piles; Johnny Fartpants; Buster Gonad; Sid the Sexist; Sweary Mary or Finbarr Saunders and his Double Entendres. Others are based on stereotypes of British culture, mostly via working class characters, such as Biffa Bacon, Cockney Wanker and The Fat Slags. In addition to this, the comic also contains plenty of 'in jokes' referring to people and places in and around Newcastle upon Tyne.
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This ability has been mapped down to a single gene, sid-2, which, when inserted as a transgene in other species, allows them to take up RNA for RNAi as C. elegans does. Research into meiosis has been considerably simplified since every germ cell nucleus is at the same given position as it moves down the gonad, so is at the same stage in meiosis. In an early phase of meiosis, the oocytes become extremely resistant to radiation and this resistance depends on expression of genes rad51 and atm that have key roles in recombinational repair. Gene mre-11 also plays a crucial role in recombinational repair of DNA damage during meiosis.
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An ovotestis is a gonad with both testicular and ovarian aspects. In humans, ovotestes are an infrequent anatomical variation associated with gonadal dysgenesis. In invertebrates that are normally hermaphroditic, such as most gastropods (snails and slugs) in the clade Eupulmonata, an ovotestis is a common feature of the reproductive anatomy. In mice, ovotestes are structured such that the central region is testicular tissue while the poles both contain ovarian tissue. Experiments involving the Sox9 gene, which is initiated by the SRY region of the Y chromosome, have shown the gene’s requirement for testicular differentiation from the presence of ovotestis formation within XX Sox9 trangenic mice. (6) Ovotestis within B6-XYPOS mice allow for gonadal development research within the same tissue to take place in ways previously unavailable.
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It is illegal to disturb the rare bird's nest, so poor Buster is forced to stay up the tree for the next few weeks until the eggs hatch and the fledglings have left the nest. In December 1987, Viz released a 7-inch single entitled "Bags of Fun With Buster" (B-side "Scrotal Scratch Mix") by Johnny Japes and His Jesticles (in reality Andy Partridge and Dave Gregory of XTC, journalist, record producer and sometime vocalist Neville Farmer, with John Otway on vocals released on Fulchester Records). Buster also featured in the 1991 Viz computer game. During the Gulf War of 1991, a SEPECAT Jaguar GR1A (number XZ118 Y) bomber of the Royal Air Force featured Buster Gonad nose art.
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As with many species of fish, the timing of spawning varies over the range of the species, with gonad development indicating that spawning in the southern New South Wales region occurs from December to April, while spawning in southern Queensland occurs from September to February. Spawning takes place twice a year, evident by the two classes of egg size found in the ovaries and by the two recruitment pulses observed each year as young fish enter their juvenile habitats. The spawning takes place at the mouths of estuaries or in surf zones, with the larvae occurring in fully marine waters. Juveniles reach 16.5 cm in length after their first year of life, 26.7 cm after their second year and 30.5 cm after their third year.
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When Price joined the lab of Carl Moore as a technician, Moore was researching "antagonistic" effects between the male and female sex steroids, testosterone and estradiol in the male reproductive system, with often confusing results. While analyzing this data, Price laid out the principle of "reciprocal influence", now known as negative feedback, where the hormone produced by the gonad could also regulate its own stimulation via its effects on the anterior pituitary. Together Moore and Price conducted experiments to show that gonadal hormones could indeed regulate the anterior pituitary (as well as vice versa), and first published the framework in 1930. The negative feedback framework would later be expanded to include the hypothalamus by Geoffrey Harris, and is currently considered a "cornerstone" of endocrinology.
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Along with a small piece of mantle tissue from another mollusk (donor shell) to serve as a catalyst for the pearl sac, it is surgically implanted into the gonad (reproductive organ) of a saltwater mollusk. In freshwater perliculture, only the piece of tissue is used in most cases, and is inserted into the fleshy mantle of the host mussel. South Sea and Tahitian pearl oysters, also known as Pinctada maxima and Pinctada margaritifera, which survive the subsequent surgery to remove the finished pearl, are often implanted with a new, larger beads as part of the same procedure and then returned to the water for another 2–3 years of growth. Despite the common misperception, Mikimoto did not discover the process of pearl culture.
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RUNX1 plays a crucial role in adult (definitive) haematopoiesis during embryonic development. It is expressed in all haematopoietic sites that contribute to the formation of haematopoietic stem and progenitor cells (HSPCs), including the yolk sac, allantois, placenta, para-aortic splanchnopleura (P-Sp; (the visceral mesodermal layer), aorta-gonad-mesonephros (AGM) and the umbilical and vitelline arteries. HSPCs are generated via the hemogenic endothelium, a special subset of endothelial cells scattered within blood vessels that can differentiate into haematopoietic cells. The emergence of HSPCs is often studied in mouse and zebrafish animal models, in which HSPCs appear as “intra-aortic” clusters that adhere to the ventral wall of the dorsal aorta. RUNX1 or CBF takes part in this process by mediating the transition of an endothelial cell to become a haematopoietic cell.
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Male Onykia ingens with penis erected to The sexes are separate in squid, there being a single gonad in the posterior part of the body with fertilisation being external, and usually taking place in the mantle cavity of the female. The male has a testis from which sperm pass into a single gonoduct where they are rolled together into a long bundle, or spermatophore. The gonoduct is elongated into a "penis" that extends into the mantle cavity and through which spermatophores are ejected. In shallow water species, the penis is short, and the spermatophore is removed from the mantle cavity by a tentacle of the male, which is specially adapted for the purpose and known as a hectocotylus, and placed inside the mantle cavity of the female during mating.
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The interior helical staircase of London City Hall The building has an unusual, bulbous shape, purportedly intended to reduce its surface area and thus improve energy efficiency, although the excess energy consumption caused by the exclusive use of glass (in a double facade) overwhelms the benefit of shape. Despite claiming the building "demonstrates the potential for a sustainable, virtually non-polluting public building", energy use measurements have shown this building to be fairly inefficient in terms of energy use (375 kWh/m2/yr), with a 2012 Display Energy Performance Certificate rating of "E". It has been compared variously to a helmet (either Darth Vader's or simply a motorcyclist's), a misshapen egg, and a woodlouse. Former mayor Ken Livingstone referred to it as a "glass testicle", while his successor, Boris Johnson, made the same comparison using a different word, "The Glass Gonad" and more politely as "The Onion".
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Trimma caudomaculatum, the blotch-tailed pygmygoby , is a species of goby from the Western Pacific. Like other members of the genus, they are usually found in large schools in the sloping or vertical drop-offs at coral reef edges. Similar to other species of Trimma this species consists of multiple cases of bidirectional sex change, meaning that if a group is lacking in a specific sex a partial amount of the group can change their undeveloped gonad structure of the opposite sex in order to accommodate. This sex change is made possible due to the females having a developed set of ovaries with female hormones that are developed, and a set of testis and male hormones that are underdeveloped; The males follow a similar set up in vice versa, so their testis and male hormones are developed, while the ovaries and female hormones are underdeveloped.
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Among others, Lemmy Kilmister will invariably be referred to as "Lemmy out of Motörhead", Bono as "Bonio" and Sting as "Sting (real name Gordon Sting)", mixing the singer's birth and stage names. One particularly memorable piece of tabloid- esque wordplay parody, involving a fictional plot to assassinate Paul McCartney by a disgruntled former roadie, read 'Top Pop Mop-Top Pot Shot Plot Flops', or with a gonad-focused violent encounter with Mr. T and a 1970s playground toy, 'BA Baracus in Macca's clackers knackers fracas'. Photos in Viz news stories are often crudely edited and altered, much to the detriment of the subjects involved (teeth blacked out, facial features shrunken/enlarged, and so on). In the case of the aforementioned Lemmy, for one photo the editors simply took a picture of a man wearing a baseball cap and drew a crude approximation of Lemmy's facial hair and warts on his face (as well as writing "Motörhead" on the cap).
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As the number of children with intersex conditions referred to Lawson Wilkins' new pediatric endocrinology clinic at Hopkins increased, it was recognized that doctors "couldn't tell by looking" at the external genitalia, and many errors of diagnosis based on outward appearance had led to anomalous sex assignments. Although it seems obvious now that a doctor could not announce to an eight-year-old boy and his parents that "we have just discovered that you are 'really' a girl, with female chromosomes, and ovaries and uterus inside, and we recommend that you change your sex to match your chromosomes and internal organs," a few such events occurred around the world as doctors and parents tried to make use of new information. Genital reconstructive surgery at that time was primarily performed on older children and adults. In the early 1950s, it consisted primarily of the ability to remove an unwanted or nonfunctional gonad, to bring a testis into a scrotum, to repair a milder chordee or to change the position of the urethra in hypospadias, to widen a vaginal opening, and to remove a clitoris.
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Some of the POR patients were born to mothers who became virilized during pregnancy, suggesting deficient placental aromatization of fetal androgens due to a lesion in microsomal aromatase resulting in low estrogen production, which was later confirmed by lower aromatase activities caused by POR mutations. However, it has also been suggested that fetal and maternal virilization in POR deficiency might be caused by increased dihydrotestosterone synthesis by the fetal gonad through an alternative "backdoor pathway" first described in the marsupials and later confirmed in humans. Gas chromatography/mass spectrometry analysis of urinary steroids from pregnant women carrying a POR-deficient fetus described in an earlier report also supports the existence of this pathway, and the relevance of the backdoor pathway along with POR dependent steroidogenesis have become clearer from recent studies. The role of POR mutations beyond CAH are being investigated; and questions such as how POR mutations cause bony abnormalities and what role POR variants play in drug metabolism by hepatic P450s are being addressed in recent publications.
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Because there is little conservation, the SRY promoter, regulatory elements and regulation are not well understood. Within related mammalian groups there are homologies within the first 400-600 base pairs upstream from the translational start site. In vitro studies of human SRY promoter have shown that a region of at least 310 bp upstream to translational start site are required for SRY promoter function. It's been shown that binding of three transcription factors, Steroidogenic factor 1 (SF1), Specificity Protein 1 (Sp1 transcription factor) and Wilms tumor protein 1 (WT1), to the human promoter sequence, influence expression of SRY. The promoter region has two Sp1 binding sites, at -150 and -13 that function as regulatory sites. Sp1 is a transcription factor that binds GC-rich consensus sequences, and mutation of the SRY binding sites leads to a 90% reduction in gene transcription. Studies of SF1 have resulted in less definite results. Mutations of SF1 can lead to sex reversal and deletion lead to incomplete gonad development. However, it's not clear how SF1 interacts with the SR1 promoter directly. The promoter region also has two WT1 binding sites at -78 and -87 bp from the ATG codon.
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