Spermatogenesis is seasonal in the large hairy armadillo, Chaetophractus villosus (Dasypodidae, Xenarthra, Mammalia)

2013 ◽  
Vol 25 (3) ◽  
pp. 547 ◽  
Author(s):  
Juan P. Luaces ◽  
Luis F. Rossi ◽  
Valeria Merico ◽  
Maurizio Zuccotti ◽  
Carlo A. Redi ◽  
...  
Keyword(s):  
Seminiferous Epithelium ◽  
Seminiferous Tubules ◽  
Ratio Analysis ◽  
Mass Ratio ◽  
Dasypus Novemcinctus ◽  
Chaetophractus Villosus ◽  
Germ Cell Differentiation ◽  
Body Mass Ratio ◽  
Low Testosterone ◽  
Euphractus Sexcinctus

Very little is known about the distinct reproductive biology of armadillos. Very few studies have investigated armadillo spermatogenesis, with data available only for Euphractus sexcinctus and Dasypus novemcinctus. In the present study, we analysed male germ cell differentiation in the large hairy armadillo Chaetophractus villosus throughout the year, describing a cycle of the seminiferous epithelium made of eight different stages. Evaluation of the testis/body mass ratio, analysis of the architecture of the seminiferous epithelium and the frequency of defective seminiferous tubules allowed identification of a temporal interruption of spermatogenesis during the period between mid-May to July (mid–end autumn) in correlation with very low testosterone levels. Overall, these results suggest that spermatogenesis is seasonal in C. villosus.

scholarly journals Estudios parasitológicos en xenartros (Mammalia: Xenarthra) del Chaco argentino y su interacción con el impacto antrópico

2020 ◽  
Author(s):  
◽  
Tatiana Agustina Ríos
Keyword(s):  
Toxoplasma Gondii ◽  
Dasypus Novemcinctus ◽  
Ancylostoma Caninum ◽  
Chaetophractus Villosus ◽  
Sarcocystis Spp ◽  
Distribución Geográfica ◽  
Para Determinar ◽  
Euphractus Sexcinctus ◽  
Intestino Delgado

La convergencia de personas, animales domésticos, animales silvestres y nuestro entorno ha creado una nueva dinámica en la que la salud de cada grupo está interconectada, es por esto que es importante comprender la dirección del flujo en los ciclos de vida de los parásitos para determinar cómo se establecen los reservorios de vida silvestre de las enfermedades parasitarias. Los xenartros, especialmente los armadillos, puedan ser reservorio de diversos parásitos y patógenos de importancia zoonótica, y los humanos que están en contacto con estos animales están expuestos a estos agentes que podrían ser un riesgo para su salud. Este grupo de mamíferos se encuentra altamente representado en la región chaqueña argentina, donde se pueden encontrar 12 de las 15 especies que se distribuyen en el país. Además, en los últimos 150 años, los drásticos cambios del paisaje, la falta de inversiones y de políticas de desarrollo sustentable en esta región desencadenaron un gran deterioro social y económico. El objetivo de esta tesis es caracterizar la diversidad de los ensambles de parásitos en xenartros en ambientes del Chaco argentino con diferente uso antrópico, y evaluar el rol de estos mamíferos como reservorio de parásitos de importancia zoonótica. Se prospectaron un total de 82 individuos hospedadores: Dasypus novemcinctus (n=4), Dasypus mazzai (n=1), Dasypus hybridus (n=9), Euphractus sexcinctus (n=6), Chaetophractus vellerosus (n=17), Chaetophractus villosus (n=4), Cabassous chacoensis (n=4), Tolypeutes matacus (n=35), Myrmecophaga tridactyla (n=1) y Tamandua tetradactyla (n=1) provenientes de distintas localidades de la región chaqueña; los helmintos hallados fueron estudiados mediante técnicas convencionales (preparados transitorios con lactofenol, preparados permanentes con bálsamo de Canadá). Además se realizaron técnicas específicas para la detección de apicomplejos parásitos y técnicas coproparasitológicas de sedimentación y de flotación. Se realizaron análisis ecológicos a nivel de comunidad componente, de población componente e infrapoblación y se analizaron los patrones de distribución de las especies de helmintos dentro del tracto gastrointestinal del hospedador. Se hallaron 35 taxones de helmintos: 28 de nematodes, 5 de cestodes y 2 de acantocéfalos. Se describieron 2 nuevas especies y un nuevo morfotipo de cestodes del género Mathevotaenia, dos morfotipos nuevos de nematodes de los géneros Delicata y Moennigia y se aportó la descripción de nuevos caracteres para los tricostrongílidos Delicata uncinata, Macielia chagasi y Macielia macieli. En cuanto a las asociaciones parásito-hospedador, se amplió el rango hospedatorio para una especie de acantocéfalo, para una especie de cestode y para 12 especies de nematodes. Se amplió la distribución geográfica de 15 especies de nematodes, entre las cuales se destacan M. chagasi, D. uncinata, Moennigia moennigi, Lauroia bolivari y Aspidodera ansirupta que fueron encontrados por primera vez en Argentina, y M. macieli, Delicata abbai, Moennigia celinae, Strongyloides dasypodis y Cyclobulura superinae que fueron hallados por primera vez en la región chaqueña. Se halló la asociación de xenartros con especies de helmintos y protozoos de importancia veterinaria y/o zoonótica como Oncicola canis, Ancylostoma caninum y Strongyloides spp., Toxoplasma gondii, Sarcocystis spp. y Cryptosporidium sp. Para evaluar el diferente uso antrópico se comparó la fauna parasitaria de poblaciones pasadas (circa 1930) vs. poblaciones actuales, enfatizando la importancia de las colecciones científicas. Al respecto, se sugirió que los helmintos parásitos hallados en cada población analizada estuvieron estrechamente asociados con los factores ambientales y ecológicos de cada grupo hospedador, destacando un efecto modulador dado posiblemente por la agriculturización de la región chaqueña. El grupo parásito más representado y con una alta dominancia fue el de los nematodes (especialmente tricostrongílidos y aspidodéridos), seguido por los cestodes y por último los acantocéfalos. Las especies hospedadoras que registraron las mayores riquezas específicas fueron T. matacus y Ch. vellerosus con 19 y 17 taxa respectivamente, seguidas por D. novemcinctus (11) y E. sexcinctus (10). Los helmintos hallados se distribuyeron a lo largo del intestino delgado siguiendo un patrón particular en cada especie hospedadora y denotando la competencia interespecífica y la segregación de nichos tróficos de las especies parásitas. Luego de más de 40 años de estudios parasitológicos en xenartros de Argentina, esta tesis sigue poniendo en evidencia la importancia de este tipo de estudios. Asimismo, destaca el rol de los armadillos como reservorio de parásitos de importancia zoonótica y/o veterinaria.

scholarly journals The Dasypodidae (Mammalia, Xenarthra) from the Urso Fóssil Cave (Quaternary), Parque Nacional de Ubajara, State of Ceará, Brazil: paleoecological and taxonomic aspects

2014 ◽  
Vol 86 (1) ◽  
pp. 147-158 ◽  
Author(s):  
PAULO V. OLIVEIRA ◽  
ANA MARIA RIBEIRO ◽  
ÉDISON V. OLIVEIRA ◽  
MARIA SOMÁLIA S. VIANA
Keyword(s):  
Environmental Conditions ◽  
Feeding Habits ◽  
Early Holocene ◽  
Northeastern Brazil ◽  
Dasypus Novemcinctus ◽  
Sediment Samples ◽  
Wide Geographical Distribution ◽  
Anthropogenic Action ◽  
Euphractus Sexcinctus ◽  
Northwest Region

This paper deals with xenarthrans osteoderms assigned to Dasypus aff. D. novemcinctus, Euphractus sexcinctus and Cabassous sp. The material was collected in subsurface, from 0.10 to 0.60 m in the Urso Fóssil Cave, Parque Nacional de Ubajara, State of Ceará, northeastern Brazil. The ages of sediment samples from levels 4 and 5 (depths of 0.40 and 0.50 m) were determined by thermoluminescence technique, and indicated ages of 8,000 and 8,200 years BP for each layer respectively. The presence in these layers of early Holocene xenarthrans taxa can contribute to the understanding of the biotic evolution of the northwest region of Ceará during the last 10,000 years. Two of the three identified taxa still occur in the region: Dasypus novemcinctus and Euphractus sexcinctus. The Dasypodidae fauna here reported includes animals with generalist feeding habits and current wide geographical distribution. It is suggested, therefore, that the climatic and environmental conditions in the early Holocene were very similar the actual ones, and that the absence of Cabassous may be conditioned to other factors, such as anthropogenic action and loss of habitat by fragmentation of the vegetation.

148. HORMONALLY REGULATED miRNAS TARGET THE TUBULOBULBAR COMPLEX IN THE TESTIS

2010 ◽  
Vol 22 (9) ◽  
pp. 66
Author(s):  
P. K. Nicholls ◽  
P. G. Stanton ◽  
K. L. Walton ◽  
R. I. McLachlan ◽  
L. O'Donnell ◽  
...  
Keyword(s):  
Sertoli Cell ◽  
Sertoli Cells ◽  
Hormonal Regulation ◽  
Focal Adhesions ◽  
Intercellular Junctions ◽  
Protein Translation ◽  
Seminiferous Epithelium ◽  
Seminiferous Tubules ◽  
Micro Rnas

Spermatogenesis is absolutely dependent on follicle stimulating hormone (FSH) and androgens; acute suppression of these hormones inhibits germ cell development and thus sperm production. The removal of intercellular junctions and release of spermatids by the Sertoli cell, a process known as spermiation, is particularly sensitive to acute hormone suppression(1). To define the molecular mechanisms that mediate FSH and androgen effects in the testis, we investigated the expression and hormonal regulation of micro-RNAs (miRNA), small non-coding RNAs that regulate protein translation and modify cellular responses. By array analysis, we identified 23 miRNAs that were upregulated >2-fold in stage VIII seminiferous tubules following hormone suppression, and in vitro in primary Sertoli cells. We subsequently validated the expression and hormonal regulation of several miRNAs, including miR-23b, -30d and -690 by quantitative PCR in primary Sertoli cells. Bioinformatic analysis of potential targets of hormonally-suppressed miRNAs identified genes associated with Focal adhesions (54 genes, P = –ln(17.97)) and the Regulation of the actin cytoskeleton (52 genes, P = –ln(10.16)), processes known to be intimately associated with adhesion of spermatids to Sertoli cells(2, 3). Furthermore, this analysis identified numerous components of the testicular tubulobulbar complex (TBC) as being targets of hormonally sensitive miRNAs. The TBC is a podosome-like structure between Sertoli and adjacent spermatids in the testis, which internalises intact inter-cellular junctions by endocytotic mechanisms prior to spermiation(4). We then demonstrate the hormonal regulation of predicted miRNA target proteins, and validate novel inhibitory miRNA interactions with Pten, nWASP, Eps15 and Picalm by luciferase knockdown in vitro. We hypothesise that hormonally suppressed miRNAs inhibit TBC function, and subsequently, endocytosis of intercellular junctions. In conclusion, we have demonstrated that hormonal suppression in the testis stimulates the expression of a subset of Sertoli cell miRNAs that are likely regulators of cell adhesion protein networks involved in spermiation. (1) Saito K, O’Donnell L, McLachlan RI, Robertson DM 2000 Spermiation failure is a major contributor to early spermatogenic suppression caused by hormone withdrawal in adult rats. Endocrinology 141: 2779–2.(2) O’Donnell L, Stanton PG, Bartles JR, Robertson DM 2000 Sertoli cell ectoplasmic specializations in the seminiferous epithelium of the testosterone-suppressed adult rat. Biol Reprod 63: 99–108.(3) Beardsley A, Robertson DM, O’Donnell L 2006 A complex containing alpha6beta1-integrin and phosphorylated focal adhesion kinase between Sertoli cells and elongated spermatids during spermatid release from the seminiferous epithelium. J Endocrinol 190(3): 759–70.(4) Young JS, Guttman JA, Vaid KS, Vogl AW 2009 Tubulobulbar complexes are intercellular podosome-like structures that internalize intact intercellular junctions during epithelial remodeling events in the rat testis. Biol Reprod 80: 162–74.

scholarly journals Male pseudohermaphroditism in dogs: three case reports

2008 ◽  
Vol 52 (No. 2) ◽  
pp. 74-78 ◽  
Author(s):  
M.R. Alam ◽  
Y.G. Cho ◽  
S.J. Cho ◽  
J.I. Lee ◽  
H.B. Lee ◽  
...  
Keyword(s):  
Undescended Testis ◽  
Case Reports ◽  
External Genitalia ◽  
Male Pseudohermaphroditism ◽  
Congenital Defects ◽  
Seminiferous Tubules ◽  
National University ◽  
Mullerian Ducts ◽  
Low Testosterone ◽  
Male Karyotype

Three Cocker Spaniel dogs, 2−3 months old, weighing 3−4 kg, were presented to the Chonbuk Animal Medical Centre, Chonbuk National University, with intersex anomalies. Physical, radiological, gross, histological, hormonal and cytogenetic studies were performed. Physical examination of the external genitalia revealed that the dogs possessed the vulva with an enlarged clitoris protruding from the vulvar juncture and the scrotum with an undescended testis in Case 1 and 2, and both testes remained undescended in Case 3. Hyperoestrogenaemia and low testosterone serum concentrations were found. Laparotomy revealed persistent Mullerian ducts (PMD) in Case 1 and 2, and abdominally located testicle(s) in all the cases. Histological examinations of the gonads revealed inactive seminiferous tubules. Cytogenetic analysis showed 78XY male karyotype in Case 1 and 2, whereas Case 3 showed 79XX female karyotype. The congenital defects were diagnosed as male pseudohermaphroditism (MPH) and PMD in Case 1 and 2, and XX sex reversal MPH in Case 3.

scholarly journals Non-random distribution of spermatogonia in rats: evidence of niches in the seminiferous tubules

Reproduction ◽  
2003 ◽  
pp. 669-680 ◽  
Author(s):  
H Chiarini-Garcia ◽  
AM Raymer ◽  
LD Russell
Keyword(s):  
Basal Lamina ◽  
Random Distribution ◽  
Type A ◽  
Seminiferous Epithelium ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Primitive Type ◽  
Linear Index ◽  
Type A Spermatogonia

The relationships and distribution of spermatogonia were studied as a function of the stage of the seminiferous epithelium cycle in rats. Primitive spermatogonia in the mouse are located along regions of the basal lamina that face the interstitium. Before studying the distribution of spermatogonia in rats, it was necessary to characterize the various types of spermatogonia, as recently performed for mice. The Strauss' linear index (Li) selectivity method was then used and spermatogonia of the A(single) (A(s)) to A(aligned) (A(al)) lineage were preferentially found to be located in regions opposing the interstitium at stages V, VII and IX of the spermatogenic cycle. Because relatively little tubule-to-tubule contact occurs in rats, the aim of this study was to determine whether tubule-to-tubule contact or tubule proximity (or alternatively, the amount of interstitium) was an important factor in spermatogonial position. In this regard, another method (tubule proximity) was devised to determine spermatogonial position that accounted for the presence of adjacent tubules. This method showed that the position of tubules, rather than tubule contact, was more accurate than the Li method in determining the location of spermatogonia in the rat. The results also showed a non-random distribution of spermatogonia resembling that of the mouse, and that tubule-to-tubule contact is not essential for the positioning of spermatogonia. In conclusion, the results of this study strongly indicate that the most primitive type A spermatogonia (A(s), A(paired) and A(al)) in rats are present in niches located in those areas of the seminiferous tubules that border the interstitial tissue.

scholarly journals Testosterone immunoreactivity in the seminiferous epithelium of rat testis: effect of treatment with ethane dimethanesulfonate.

1989 ◽  
Vol 37 (11) ◽  
pp. 1667-1673 ◽  
Author(s):  
R Schulz ◽  
F Paris ◽  
P Lembke ◽  
V Blüm
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Time Course ◽  
Seminiferous Epithelium ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Treatment Level ◽  
Cell Nuclei ◽  
Testicular Weight

Androgens drive spermatogenesis by processes that are largely unknown. Direct effects on germ cells and indirect effects mediated via testicular somatic elements are currently under consideration, and specific localization of androgens in seminiferous tubules may provide information as regards this. Adult male rats were injected with ethane dimethanesulfonate (EDS; 75 mg/kg body weight) or vehicle. Testes were fixed and paraffin-embedded for localization of testosterone immunoreactivity 1 and 2 weeks after treatment, using the unlabeled antibody (PAP) technique. Plasma testosterone dropped from a pre-treatment level of 2.3 ng/ml to below 0.2 ng/ml 3 days after EDS injection and remained at low levels until the end of observation, accompanied by a progressive decrease in testicular weight. In the seminiferous tubules of vehicle-injected males, testosterone immunoreactivity was found in nuclei of spermatocytes and spermatids and in nuclei and the cytoplasm of Sertoli cells, and showed typical variations according to the stage of spermatogenesis. One week after EDS treatment, immunoreactivity had disappeared from the seminiferous epithelium. Two weeks after treatment, staining of germ cells was detected in two out of four males. The disappearance and reappearance of immunoreactivity coincided with the time course of EDS effects on rat Leydig cells, and we conclude that it corresponds to androgen specifically localized in fixed, paraffin-embedded tissue. Because staining of germ cell nuclei varied with the stage of spermatogenesis, the technique may detect a physiologically relevant androgen fraction; its location suggests that androgens may also directly affect certain germ cell stages.

scholarly journals Hereditary Sterilizing Short-Tail Sperm Defect in Finnish Yorkshire Boars

2002 ◽  
Vol 14 (5) ◽  
pp. 382-388 ◽  
Author(s):  
Antti Sukura ◽  
Raili Mäkipää ◽  
Matti Vierula ◽  
Heriberto Rodriguez-Martinez ◽  
Pernilla Sundbäck ◽  
...  
Keyword(s):  
Leydig Cells ◽  
Testicular Tissue ◽  
Seminiferous Epithelium ◽  
Characteristic Change ◽  
Seminiferous Tubules ◽  
Light Microscopic Level ◽  
Tissue Samples ◽  
Tissue Sections ◽  
Typical Finding ◽  
And Control

A new infertility syndrome has recently been described in Finnish Yorkshire boars. Typical for the syndrome is total akinesia and severe tail malformation of the spermatozoa. Morphometric analysis was performed on semen smears from 20 affected and 18 control boars and on testicular tissue sections from 5 affected and 4 control boars. Semen morphometry revealed that, in affected boars, the length of the sperm tails was only 33% of that of the controls (15.4 μm vs. 47.0 μm, P < 0.0001). Typical for the spermatozoa of affected boars was also an abundant frequency of proximal cytoplasmic droplets (72.4% vs. 6.9%, P < 0.0001), whereas no major sperm-head abnormalities were recorded. In the testicular tissue samples, viewed at light microscopic level, the volume densities of seminiferous tubules or interstitium did not differ. The most characteristic change in the seminiferous epithelium of the affected boars was a reduced number of elongated spermatids. Densities of Sertoli cells and Leydig cells between affected and control boars did not differ. The ultrastructure of testicular tissue from affected boars showed severe alterations in the assembly of the midpiece and tail of the spermatozoa. As well, a typical finding in the seminiferous epithelium of affected boars was conspicuous deposition of lipid droplets. The pathogenesis of this syndrome severely affects spermiogenesis and motility. Spermatozoa have malformed, short tails, which never become motile. This syndrome is not manifested in the structure or function of other ciliated cells in the affected animals.

scholarly journals Perturbation of spermatogenesis by androgen antagonists directly injected into seminiferous tubules of live mice

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Kaz Nagaosa ◽  
Atsushi Kishimoto ◽  
Ryoichi Kizu ◽  
Akihisa Nakagawa ◽  
Akiko Shiratsuchi ◽  
...  
Keyword(s):  
Seminiferous Epithelium ◽  
Assay System ◽  
Seminiferous Tubules ◽  
Permeability Barrier ◽  
Gonadal Function ◽  
Sperm Production ◽  
Physiological Conditions ◽  
Androgen Antagonists ◽  
Severe Impairment ◽  
Blood Testis Barrier

Natural and artificial substances present in the environment can affect our health. Testicular toxicants in particular are troublesome, because they disturb gonadal function of males. Translocation of substances into the seminiferous epithelium where sperm production proceeds is restricted due to the blood–testis barrier, but this permeability barrier temporarily disappears under physiological and sub-physiological conditions. This means that any substance could enter the seminiferous epithelium and disturb sperm production. To reduce the risk posed by such toxins, it is important to accurately determine which substances possess the toxicity. However, existing assay systems are not satisfactory in terms of both accuracy and sensitivity. Here, we report the establishment of such a system. We injected the androgen antagonists, flutamide and vinclozolin, directly into seminiferous tubules of live mice, which had been treated with busulfan for a temporal arrest of spermatogenesis, and the testes were histologically examined to see the effect of the injected materials on spermatogenesis that was in the process of recovery. The injection of either substance brought about a severe impairment of spermatogenesis at an amount over a million times smaller than that used in the previous assay systems where animals are administered with test substances outside of the testis. In contrast, these androgen antagonists at the same doses showed lesser effects when intratubularly or intraperitoneally administered into mice that had not been pretreated with busulfan. We propose that the method adopted in this study is a novel assay system to identify potential testicular toxicants.

scholarly journals Rhox13 is required for a quantitatively normal first wave of spermatogenesis in mice

Reproduction ◽  
2016 ◽  
Vol 152 (5) ◽  
pp. 379-388 ◽  
Author(s):  
Jonathan T Busada ◽  
Ellen K Velte ◽  
Nicholas Serra ◽  
Kenneth Cook ◽  
Bryan A Niedenberger ◽  
...  
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Histological Analysis ◽  
Gene Knockout ◽  
Cell Types ◽  
Seminiferous Tubules ◽  
Germ Cell Differentiation ◽  
Sperm Counts ◽  
Full Complement ◽  
Specific Association

We previously described a novel germ cell-specific X-linkedreproductivehomeoboxgene (Rhox13) that is upregulated at the level of translation in response to retinoic acid (RA) in differentiating spermatogonia and preleptotene spermatocytes. We hypothesize that RHOX13 plays an essential role in male germ cell differentiation, and have tested this by creating aRhox13gene knockout (KO) mouse.Rhox13KO mice are born in expected Mendelian ratios, and adults have slightly reduced testis weights, yet a full complement of spermatogenic cell types. Young KO mice (at ~7–8 weeks of age) have a ≈50% reduction in epididymal sperm counts, but numbers increased to WT levels as the mice reach ~17 weeks of age. Histological analysis of testes from juvenile KO mice reveals a number of defects during the first wave of spermatogenesis. These include increased apoptosis, delayed appearance of round spermatids and disruption of the precise stage-specific association of germ cells within the seminiferous tubules. Breeding studies reveal that both young and aged KO males produce normal-sized litters. Taken together, our results indicate that RHOX13 is not essential for mouse fertility in a controlled laboratory setting, but that it is required for optimal development of differentiating germ cells and progression of the first wave of spermatogenesis.

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