scholarly journals Morphology of the genital organs of male and female giant anteaters (Myrmecophaga tridactyla)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11945
Author(s):  
Lilja Fromme ◽  
Débora R. Yogui ◽  
Mario Henrique Alves ◽  
Arnaud L.J. Desbiez ◽  
Marion Langeheine ◽  
...  

Background The giant anteater belongs to the supraorder Xenarthra which occupies a systematically isolated position among placental mammals. The species is categorized as Vulnerable by the International Union for Conservation of Nature, and understanding its reproductive characteristics is critical for future conservation efforts. Methods Gross and microscopic anatomy of the genital organs of 23 male and 21 female adult and young roadkill giant anteaters in Brazil were studied. Results Male giant anteaters presented a short conical penis, intraabdominal testes, and prostate, vesicular and bulbourethral glands. A tubular remnant of the partially fused Müllerian ducts extended from the seminal colliculus through the prostate gland, continued cranially in the genital fold, bifurcated, and attached with one elongation each to the left and right epididymal corpus. The structure presented a total length of up to 10 cm and contained a yellowish liquid in its lumen. Histologically, the caudal section of this structure resembled the female vagina, the middle portion corresponded to the uterus, and the extensions showed characteristics of uterine tubes. In adult female giant anteaters, ovoid ovaries with occasional seminiferous cord-like structures were observed. The animals possessed a simple uterus, which was directly continuous with the vaginal canal. The caudal portion of the vagina had two lumina, separated by a longitudinal septum and opening into two apertures into the vaginal vestibule, cranial to the urethral opening. In the urethral and the lateral vestibular wall, glandular structures with characteristics of male prostate and bulbourethral glands, respectively, were found. The vestibule opened through a vertical vulvar cleft to the exterior. A pair of well-differentiated Wolffian ducts with a central lumen originated ventrally at the vaginal opening into the vestibule and passed in a cranial direction through the ventral vaginal and uterine wall. Each duct extended highly coiled along the ipsilateral uterine tube until the lateral pole of the ovaries where it merged with the rete ovarii. Discussion The reproductive morphology of giant anteaters reveals characteristics shared with other Xenarthrans: intraabdominal testes, a simple uterus, and a double caudal vagina. The persistence of well-differentiated genital ducts of the opposite sex in both males and females, however, singles them out among other species. These structures are the results of an aberration during fetal sexual differentiation and possess secretory functions. The possibility of a pathological degeneration of these organs should be considered in reproductive medicine of the species. Conclusion Knowledge of the unique reproductive characteristics of the giant anteater is essential for future reproductive management of the species. Additionally, further research on the peculiarities of the persisting genital duct structures might help to understand sexual differentiation in placental mammals in general.

Development ◽  
1973 ◽  
Vol 30 (1) ◽  
pp. 143-161
Author(s):  
Par J. C. Relexans

Transplantations of undifferentiated gonads in the simultaneous hermaphrodite Eisenia foetida (Oligochaeta, Lumbricidae) leading to evidence of local factors (inductors?) of sexual differentiation The hypothesis of a ♀ sex capable of autodifferentiation and of a ♂ sex depending on an androgen hormone has been verified in several gonochoric or hermaphrodite invertebrates. In order to test the validity of this hypothesis in the hermaphrodite Eisenia foetida we have investigated the influence of the gonads' environment on their differentiation by transplanting undifferentiated gonads, dorsally and ventrally, on different parts of the body. The gonads, taken with the adjacent wall of the body from new-born worms, are grafted on worms of the same age; some grafts do, others do not, retain their nervous system. The control transplantation in which a graft of a given presumptive sex is transplanted in a region of the same sex can lead to inversions. These inversions have a rare and short-lived character in the gonads coming from presumptive testes. They are more frequent and more or less durable in the gonads coming from presumptive ovaries. These results can only be explained by the existence, within the grafts of the two presumptive sexes, of a dominant relationship between one and the other sexual potentiality which can be momentarily inverted by trophic disturbances caused by the transplantation. The heterosexual transplantations, in which a graft of a given presumptive sex is transplanted in the region of the opposite sex, show that the frequency of the inversions is doubled in relation to the frequency obtained in the control transplantations. The inversions which occur in the presumptive testes can be lasting and even permanent. These results lead to the opinion that to the effects of transplantation is added an inductive action from the host, leading to masculinity in the ♂ region and femininity in the ♀ region. The transplantations outside of the sexual ventral regions lead to inversions of which the character and frequency recall those obtained in the control transplantations. They suggest that these regions are devoid of inductive sexualizing power. The very slight variations of frequency of the inversions observed along the antero-posterior and dorso-ventral axes can be explained by the existence of physiological gradients acting on the balance of the graft's own potentialities. The removal of the nervous system in the grafts shows that this system plays a part, probably trophic, in favour of the masculine potentialities of the graft. In conclusion, our experiments lead to the rejection of the hypothesis of the ♀ sex capable of autodifferentiation in Eisenia, in order to adopt that of a sexual balance between the ♂ and ♀ potentialities determining, according to their dominant relationship, the synthesis of ♂ or ♀ ‘inductors’ respectively in the ♂ and ♀ ventral regions. These inductors act in turn on the bipotential sexual cells.


Nature ◽  
1962 ◽  
Vol 193 (4810) ◽  
pp. 88-89 ◽  
Author(s):  
TERRELL H. HAMILTON

Author(s):  
Louis J. G. Gooren

Transsexualism is the condition in which a person with apparently normal somatic sexual differentiation is convinced that he/she is actually a member of the opposite sex. It is associated with an irresistible urge to be hormonally and surgically adapted to that sex. Traditionally transsexualism has been conceptualized as a purely psychological phenomenon, but research on the brains of male-to-female transsexuals has found that the sexual differentiation of the brain—the bed nucleus of the stria terminalis (BSTC) and the hypothalamic uncinate nucleus—had followed a female pattern (1). This finding may lead to a concept of transsexualism as a form of intersex, where the sexual differentiation of the brain (which in mammals also undergoes sexual differentiation) is not consistent with the other variables of sex, such as chromosomal pattern, nature of the gonad and nature of internal/external genitalia. Thus it can be argued that transsexualism is a sexual differentiation disorder.


Reproduction ◽  
2002 ◽  
pp. 73-83 ◽  
Author(s):  
D Coveney ◽  
G Shaw ◽  
MB Renfree

This study reports the effect of oestrogen treatment on the development of the genital ducts, prostate gland, testicular descent and inguinal canal closure in male tammar wallaby young treated with oestrogen over four time spans during the first 25 days of pouch life (days 0-10, 10-15, 15-25 and 0-25) and sampled at day 50. In control males, the Mullerian ducts had regressed and the Wolffian ducts had developed into the vas deferens and epididymis. The prostate gland had formed epithelial buds extending from the ventral, lateral and posterior walls of the urethra. The testes were in the neck of the scrotum and the gubernaculum and processus vaginalis were present at the base of the scrotum. In most males treated with oestradiol from day 0 to day 25, the testes had failed to descend by day 50. The gubernaculae were long and thin. The retained Mullerian ducts formed a lateral vaginal expansion like that of normal day 50 females. The Wolffian ducts of the males treated on days 0-25 were regressed, but were present in males in the other three treatment groups. The prostate glands were hyperplastic and epithelial budding was highly invasive. Some treated males from the day 10-25 and 0-25 groups had inguinal hernias. These results demonstrate that oestrogen treatment has profound effects on the development of the internal genitalia of a male marsupial, preventing inguinal closure and interfering with testicular descent. Therefore, the tammar wallaby may provide a useful experimental model animal in which to investigate the hormonal control of testicular migration and closure of the inguinal canal.


1981 ◽  
Vol 18 (6) ◽  
pp. 707-713 ◽  
Author(s):  
F. Deerberg ◽  
S. Rehm ◽  
W. Pittermann

In a longevity study on 320 male and 320 female specified-pathogen-free Han: Wistar rats, 119 (39.0%) of 305 females evaluated developed spontaneous metastatic uterine adenocarcinomas. These tumors caused a great difference between the mortality rates of males and females. Thirty five percent of the females died of adenocarcinomas of the uterus. The tumors began as small nodules in one or both horns near the bifurcation. Large tumors extended through the uterine wall and produced wide-spread transcoelomic metastases. Early lesions were well-differentiated adenocarcinomas but advanced tumors were more poorly differentiated.


Author(s):  
David S. Klimstra ◽  
Himisha Beltran ◽  
Rogerio Lilenbaum ◽  
Emily Bergsland

Neuroendocrine neoplasms are diverse in terms of sites of origin, functional status, and degrees of aggressiveness. This review will introduce some of the common features of neuroendocrine neoplasms and will explore the differences in pathology, classification, biology, and clinical management between tumors of different anatomic sites, specifically, the lung, pancreas, and prostate. Despite sharing neuroendocrine differentiation and histologic evidence of the neuroendocrine phenotype in most organs, well-differentiated neuroendocrine tumors (WD-NETs) and poorly differentiated neuroendocrine carcinomas (PD-NECs) are two very different families of neoplasms. WD-NETs (grade 1 and 2) are relatively indolent (with a natural history that can evolve over many years or decades), closely resemble non-neoplastic neuroendocrine cells, and demonstrate production of neurosecretory proteins, such as chromogranin A. They arise in the lungs and throughout the gastrointestinal tract and pancreas, but WD-NETs of the prostate gland are uncommon. Surgical resection is the mainstay of therapy, but treatment of unresectable disease depends on the site of origin. In contrast, PD-NECs (grade 3, small cell or large cell) of all sites often demonstrate alterations in P53 and Rb, exhibit an aggressive clinical course, and are treated with platinum-based chemotherapy. Only WD-NETs arise in patients with inherited neuroendocrine neoplasia syndromes (e.g., multiple endocrine neoplasia type 1), and some common genetic alterations are site-specific (e.g., TMPRSS2-ERG gene rearrangement in PD-NECs arising in the prostate gland). Advances in our understanding of the molecular basis of NETs should lead to new diagnostic and therapeutic strategies and is an area of active investigation.


Behaviour ◽  
1996 ◽  
Vol 133 (11-12) ◽  
pp. 847-862 ◽  
Author(s):  
E. Adkins-Regan ◽  
S. Yang ◽  
V. Mansukhani

In order to test hypotheses about the organizational role of early estrogen in the sexual differentiation of behavior in zebra finches (Taeniopygia guttata), newly hatched birds were given one of three treatments: (1) daily injection with an aromatase inhibitor (fadrozole hydrochloride) for the first week; (2) the same treatment for the first two weeks; (3) daily injection of the vehicle for one or two weeks. As adults, birds were implanted with testosterone propionate and underwent a three-phase testing procedure designed to measure singing, dancing, copulation, and preferences for male vs female partners. Males were completely unaffected by fadrozole hydrochloride treatment; they sang, danced, and mounted at control levels, and like control males they preferred female partners. Females were similarly unaffected, with one important exception: those treated with fadrozole hydrochloride during the first week preferred to be spend time near females instead of males in choice tests, unlike control females. These results suggest that a model of zebra finch sexual differentiation in which estrogen organizes male-typical behavior is unlikely to be correct. At the same time, they provide evidence that a key dimorphic feature of mate choice, preference for opposite-sex birds (sexual orientation), may result from organizational hormone actions during the early post-hatching period in this pair-bonding species.


Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2422
Author(s):  
Dragos Scarlet ◽  
Stephan Handschuh ◽  
Ursula Reichart ◽  
Giorgia Podico ◽  
Robyn E. Ellerbrock ◽  
...  

It was the aim of this study to characterize the development of the gonads and genital ducts in the equine fetus around the time of sexual differentiation. This included the identification and localization of the primordial germ cell population. Equine fetuses between 45 and 60 days of gestation were evaluated using a combination of micro-computed tomography scanning, immunohistochemistry, and multiplex immunofluorescence. Fetal gonads increased in size 23-fold from 45 to 60 days of gestation, and an even greater increase was observed in the metanephros volume. Signs of mesonephros atrophy were detected during this time. Tubular structures of the fetal testes were present from day 50 onwards, whereas cell clusters dominated in the fetal ovary. The genital ducts were well-differentiated and presented a lumen in all samples. No sign of mesonephric or paramesonephric duct degeneration was detected. Expression of AMH was strong in the fetal testes but absent in ovaries. Irrespective of sex, primordial germ cells selectively expressed LIN28. Migration of primordial germ cells from the mesonephros to the gonad was detected at 45 days, but not at 60 days of development. Their number and distribution within the gonad were influenced (p < 0.05) by fetal sex. Most primordial germ cells (86.8 ± 3.2% in females and 84.6 ± 4.7% in males) were characterized as pluripotent according to co-localization with CD117. However, only a very small percentage of primordial germ cells were proliferating (7.5 ± 1.7% in females and 3.2 ± 1.2% in males) based on co-localization with Ki67. It can be concluded that gonadal sexual differentiation in the horse occurs asynchronously with regard to sex but already before 45 days of gestation.


2020 ◽  
Vol 56 (3) ◽  
pp. 192
Author(s):  
Ahmad Yudianto ◽  
Ariyanto Wibowo ◽  
Indah Nuraini ◽  
Htet Htet Aung

The presence of spermatozoa in vagina is a definite sign of sexual intercourse. However, sometimes microscopic examination does not find spermatozoa or reveals a false negative result. This is influenced by many factors, including the absence of ejaculate in the vaginal canal. In addition, there are other factors such as oligo/azoospermia, vasectomy, degeneration of sperm due to time, incorrect sampling, and improper storage. Therefore, examination of the other components of the ejaculate, ie. the enzyme acid phosphatase, choline and spermin, is important. Compared with spermatozoa, the enzyme phosphatase, choline and spermin have lower evidentiary value because these three components are less specific. However, the level of phosphatase enzyme found in the vagina is much lower than phosphatase enzyme that comes from prostate gland. In this study, as many as 192 samples in the form of patches with sperm/semen stains were tested with acid phosphatase test and zinc test through direct and indirect examination. Washing was carried out using 7 types of detergent for each 4 patch samples, and washing using water as control. The results showed very low sensitivity (0.186) and very high specificity (100%). This showed that both tests had high specificity values. Acid phosphatase test specifically showed the presence of the enzyme phosphatase, while zinc test specifically showed the presence of zinc in semen. This phosphohydrolase-phosphatase enzyme is easily degraded due to external factors, including temperature, humidity, and chemicals, ie. the element SDS (Sodium Dodecyl Sulfate) that has the ability to cut enzymes. The weakness of the acid phosphatase test is that this enzyme is easily degraded, either partially or completely, due to external factors, such as temperature, humidity, heat, and the presence of chemicals.


2021 ◽  
Vol 56 (3) ◽  
pp. 192
Author(s):  
Ahmad Yudianto ◽  
Ariyanto Wibowo ◽  
Indah Nuraini ◽  
Htet Htet Aung

The presence of spermatozoa in vagina is a definite sign of sexual intercourse. However, sometimes microscopic examination does not find spermatozoa or reveals a false negative result. This is influenced by many factors, including the absence of ejaculate in the vaginal canal. In addition, there are other factors such as oligo/azoospermia, vasectomy, degeneration of sperm due to time, incorrect sampling, and improper storage. Therefore, examination of the other components of the ejaculate, ie. the enzyme acid phosphatase, choline and spermin, is important. Compared with spermatozoa, the enzyme phosphatase, choline and spermin have lower evidentiary value because these three components are less specific. However, the level of phosphatase enzyme found in the vagina is much lower than phosphatase enzyme that comes from prostate gland. In this study, as many as 192 samples in the form of patches with sperm/semen stains were tested with acid phosphatase test and zinc test through direct and indirect examination. In the first method, washing was carried out on day 1, day 7, and month 3, and testing was carried out after each washing. In the second method, washing was carried out simultaneously and testing was carried out on day 1, day 7 and month 3. Washing was carried out using 7 types of detergent for each 4 patch samples, and washing using water as control. The results showed very low sensitivity (0.186) and very high specificity (100%). This showed that both tests had high specificity values. Acid phosphatase test specifically showed the presence of the enzyme phosphatase, while zinc test specifically showed the presence of zinc in semen. This phosphohydrolase-phosphatase enzyme is easily degraded due to external factors, including temperature, humidity, and chemicals, ie. the element SDS (Sodium Dodecyl Sulfate) that has the ability to cut enzymes. The weakness of the acid phosphatase test is that this enzyme is easily degraded, either partially or completely, due to external factors, such as temperature, humidity, heat, and the presence of chemicals.


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