Gonadal sex differentiation in the neonatal marsupial, Monodelphis domestica

Development ◽  
1990 ◽  
Vol 109 (3) ◽  
pp. 699-703
Author(s):  
P.J. Baker ◽  
H.D. Moore ◽  
L.M. Penfold ◽  
A.M. Burgess ◽  
U. Mittwoch
Keyword(s):  
Sex Chromosomes ◽  
Tunica Albuginea ◽  
Histological Study ◽  
Sex Differentiation ◽  
In Utero ◽  
Monodelphis Domestica ◽  
Gonadal Differentiation ◽  
Marsupial Species

A quantitative and histological study of the gonads of newborn grey short-tailed opossums, Monodelphis domestica, is described. The pups were karyotyped, and comparisons were made within litters segregating for XX and XY sex chromosomes. A total of four litters including 25 pups were available. On the day of birth, developing testes were significantly larger than the ovaries of litter mates, and testes could be histologically distinguished by the formation of sex cords and a tunica albuginea. The data suggest that in this marsupial species gonadal differentiation may be initiated in utero.

scholarly journals Müllerian Inhibiting Substance Is Required for Germ Cell Proliferation during Early Gonadal Differentiation in Medaka (Oryzias latipes)

Endocrinology ◽  
2007 ◽  
Vol 149 (4) ◽  
pp. 1813-1819 ◽  
Author(s):  
Eri Shiraishi ◽  
Norifumi Yoshinaga ◽  
Takeshi Miura ◽  
Hayato Yokoi ◽  
Yuko Wakamatsu ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Germ Cell ◽  
Germ Cells ◽  
Sex Differentiation ◽  
Somatic Cells ◽  
Oryzias Latipes ◽  
Cell Number ◽  
Gonadal Differentiation ◽  
Loss Of Function ◽  
Germ Cell Proliferation

Müllerian inhibiting substance (MIS) is a glycoprotein belonging to the TGF-β superfamily. In mammals, MIS is responsible for the regression of Müllerian ducts in the male fetus. However, the role of MIS in gonadal sex differentiation of teleost fish, which have no Müllerian ducts, has yet to be clarified. In the present study, we examined the expression pattern of mis and mis type 2 receptor (misr2) mRNAs and the function of MIS signaling in early gonadal differentiation in medaka (teleost, Oryzias latipes). In situ hybridization showed that both mis and misr2 mRNAs were expressed in the somatic cells surrounding the germ cells of both sexes during early sex differentiation. Loss-of-function of either MIS or MIS type II receptor (MISRII) in medaka resulted in suppression of germ cell proliferation during sex differentiation. These results were supported by cell proliferation assay using 5-bromo-2′-deoxyuridine labeling analysis. Treatment of tissue fragments containing germ cells with recombinant eel MIS significantly induced germ cell proliferation in both sexes compared with the untreated control. On the other hand, culture of tissue fragments from the MIS- or MISRII-defective embryos inhibited proliferation of germ cells in both sexes. Moreover, treatment with recombinant eel MIS in the MIS-defective embryos dose-dependently increased germ cell number in both sexes, whereas in the MISRII-defective embryos, it did not permit proliferation of germ cells. These results suggest that in medaka, MIS indirectly stimulates germ cell proliferation through MISRII, expressed in the somatic cells immediately after they reach the gonadal primordium.

Cytogenetic, anatomical and blood group studies of sheep twin chimaeras

1970 ◽  
Vol 175 (1039) ◽  
pp. 183-200 ◽  
Keyword(s):  
Blood Cell ◽  
Blood Group ◽  
Sex Chromosomes ◽  
Cell Types ◽  
In Utero ◽  
Red Cells ◽  
Cell Populations ◽  
Red Cell ◽  
X Protein ◽  
Blood Grouping

Karyotyping and blood grouping methods were used to identify sheep twin chimaeras. Evidence that an exchange of blood cell precursors (the origin of chimaerism) had taken place in utero was obtained by examining lymphocytes in culture and finding the chromosomes of both sexes in one individual, or by finding admixture of red cell antigens, haemoglobin or ‘X ’ protein. Where chimaerism of sex chromosomes was found the pairs had identical red cell types, but two separate populations of red cells were not always identifiable. The four females in the pairs studied were freemartins. No correlation was found between the relative proportions of the two red cell populations and those of the two white cell populations. In one pair of chimaeric ewes, breeding tests showed that the major red cell populations in each case were the true genetic type. In the freemartins no correlation was found between the degree of masculinity and the numbers of male lymphocytes. A possible correlation of masculinity with red cell proportions is discussed.

scholarly journals Cortical plasticity following stripe rearing in the marsupialMonodelphis domestica: neural response properties of V1

2017 ◽  
Vol 117 (2) ◽  
pp. 566-581 ◽  
Author(s):  
James C. Dooley ◽  
Michaela S. Donaldson ◽  
Leah A. Krubitzer
Keyword(s):  
Visual System ◽  
Cortical Neurons ◽  
Functional Organization ◽  
Sensory Experience ◽  
Monodelphis Domestica ◽  
Visual Environment ◽  
Visual Response ◽  
Response Properties ◽  
Dependent Plasticity ◽  
Marsupial Species

The functional organization of the primary visual area (V1) and the importance of sensory experience in its normal development have been well documented in eutherian mammals. However, very few studies have investigated the response properties of V1 neurons in another large class of mammals, or whether sensory experience plays a role in shaping their response properties. Thus we reared opossums ( Monodelphis domestica) in normal and vertically striped cages until they reached adulthood. They were then anesthetized using urethane, and electrophysiological techniques were used to examine neuronal responses to different orientations, spatial and temporal frequencies, and contrast levels. For normal opossums, we observed responses to the temporal and spatial characteristics of the stimulus to be similar to those described in small, nocturnal, eutherian mammals such as rats and mice; neurons in V1 responded maximally to stimuli at 0.09 cycles per degree and 2.12 cycles per second. Unlike other eutherians, but similar to other marsupials investigated, only 40% of the neurons were orientation selective. In stripe-reared animals, neurons were significantly more likely to respond to vertical stimuli at a wider range of spatial frequencies, and were more sensitive to gratings at lower contrast values compared with normal animals. These results are the first to demonstrate experience-dependent plasticity in the visual system of a marsupial species. Thus the ability of cortical neurons to alter their properties based on the dynamics of the visual environment predates the emergence of eutherian mammals and was likely present in our earliest mammalian ancestors.NEW & NOTEWORTHY These results are the first description of visual response properties of the most commonly studied marsupial model organism, the short-tailed opossum ( Monodelphis domestica). Further, these results are the first to demonstrate experience-dependent plasticity in the visual system of a marsupial species. Thus the ability of cortical neurons to alter their properties based on the dynamics of the visual environment predates the emergence of eutherian mammals and was likely present in our earliest mammalian ancestors.

Entrainment of circadian phase in developing gray short-tailed opossums: mother vs. environment.

1990 ◽  
Vol 259 (3) ◽  
pp. E384
Author(s):  
S A Rivkees ◽  
S M Reppert
Keyword(s):  
Circadian Clock ◽  
Metabolic Activity ◽  
Biological Clock ◽  
Monodelphis Domestica ◽  
Dark Cycle ◽  
Circadian Phase ◽  
Environmental Light ◽  
Circadian Time ◽  
Retinohypothalamic Tract ◽  
Marsupial Species

In a marsupial species, the gray short-tailed opossum (Monodelphis domestica), the suprachiasmatic nuclei (SCN), the site of a circadian clock, are formed postnatally and begin oscillating as a circadian clock on day 20. In this study, we examined how the timing (phase) of the SCN clock in the developing opossum is coordinated to the environmental light-dark cycle. When pups were reared from birth in darkness by intact dams, the circadian phases in SCN metabolic activity (monitored by 2-deoxy-D-[14C]glucose autoradiography) in 27-day-old pups were desynchronized. When pups were reared in a light-dark cycle that was 12 h out of phase with the circadian time of blinded dams, the pattern of SCN metabolic activity on day 20 was rhythmic and in phase with the light-dark cycle but out of phase with the circadian time of the dam. On day 20, retina-mediated light activation of SCN metabolic activity was also demonstrated, and anterograde tract-tracing studies revealed the presence of the retinohypothalamic tract within the SCN. These results show there is no influence of the opossum dam on the timing of the pup's biological clock. Instead, from the inception of the daily rhythm in SCN metabolic activity, its timing is regulated by retina-mediated light-dark entrainment.

scholarly journals Folic acid supplementation reduces multigenerational sperm miRNA perturbation induced by in utero environmental contaminant exposure

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
P M Herst ◽  
M Dalvai ◽  
M Lessard ◽  
P L Charest ◽  
P Navarro ◽  
...  
Keyword(s):  
Folic Acid ◽  
Target Genes ◽  
Corn Oil ◽  
System Development ◽  
Sex Differentiation ◽  
Control Diet ◽  
Folic Acid Supplementation ◽  
In Utero ◽  
Contaminant Exposure ◽  
Two Generations

Abstract Persistent organic pollutants (POPs) can induce epigenetic changes in the paternal germline. Here, we report that folic acid (FA) supplementation mitigates sperm miRNA profiles transgenerationally following in utero paternal exposure to POPs in a rat model. Pregnant founder dams were exposed to an environmentally relevant POPs mixture (or corn oil) ± FA supplementation and subsequent F1–F4 male descendants were not exposed to POPs and were fed the FA control diet. Sperm miRNA profiles of intergenerational (F1, F2) and transgenerational (F3, F4) lineages were investigated using miRNA deep sequencing. Across the F1–F4 generations, sperm miRNA profiles were less perturbed with POPs+FA compared to sperm from descendants of dams treated with POPs alone. POPs exposure consistently led to alteration of three sperm miRNAs across two generations, and similarly one sperm miRNA due to POPs+FA; which was in common with one POPs intergenerationally altered sperm miRNA. The sperm miRNAs that were affected by POPs alone are known to target genes involved in mammary gland and embryonic organ development in F1, sex differentiation and reproductive system development in F2 and cognition and brain development in F3. When the POPs treatment was combined with FA supplementation, however, these same miRNA-targeted gene pathways were perturbed to a lesser extend and only in F1 sperm. These findings suggest that FA partially mitigates the effect of POPs on paternally derived miRNA in a intergenerational manner.

scholarly journals Cerebral and gonadal aromatase expressions are differently affected during sex differentiation of Pleurodeles waltl

2004 ◽  
Vol 33 (3) ◽  
pp. 717-727 ◽  
Author(s):  
Sandra Kuntz ◽  
Amand Chesnel ◽  
Stéphane Flament ◽  
Dominique Chardard
Keyword(s):  
Sex Differentiation ◽  
Temperature Sensitive ◽  
Aromatase Activity ◽  
Gonadal Differentiation ◽  
Aromatase Expression ◽  
Larval Stages ◽  
Exon 1 ◽  
The Individual ◽  
Pleurodeles Waltl ◽  
The Brain

In vertebrates, sex is determined essentially by two means, genetic factors located on sex chromosomes and epigenetic factors such as temperature experienced by the individual during development. Steroids, especially estrogens, are clearly involved in gonadal differentiation in non-mammalian vertebrates. In this regard, the expression of the estrogen-producing enzyme, aromatase, has been shown to be temperature-sensitive in species where temperature can reverse sex differentiation, especially in our model, the amphibian Pleurodeles waltl. We investigated here the regulation of aromatase expression in the brain during sex differentiation in Pleurodeles. We first isolated a brain isoform of aromatase mRNA which differs in its 5′ untranslated region from the isoform previously isolated from adult gonads. In adult Pleurodeles, the brain isoform is mainly expressed in brain tissue while the other isoform is gonad specific. Thus, regulation of aromatase expression in P. waltl could occur by alternative splicing of non-coding exon 1 as previously described in mammals. We then investigated aromatase expression in the brain of male and female larvae and found no differences with regard to sex. Measures of aromatase activity in the brain also showed no differences between sexes at larval stages whereas activity markedly increases in the ovary concomitant with the start of gonadal differentiation. These results support the hypothesis that aromatase could be a target of a temperature-sensitive sex-reversing effect in the gonads but not in the brain.

scholarly journals Interaction between sex-determining genes from two species: clues from Xenopus hybrids

2021 ◽  
Vol 376 (1833) ◽  
pp. 20200104 ◽  
Author(s):  
Álvaro S. Roco ◽  
Adrián Ruiz-García ◽  
Mónica Bullejos
Keyword(s):  
Sex Chromosomes ◽  
Ovarian Development ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Parental Species ◽  
Z Chromosome ◽  
Gonadal Differentiation ◽  
Theme Issue ◽  
Testicular Differentiation

Hybrids provide an interesting model to study the evolution of sex-determining genes and sex chromosome systems as they offer the opportunity to see how independently evolving sex-determining pathways interact in vivo . In this context, the genus Xenopus represents a stimulating model, since species with non-homologous sex chromosomes and different sex-determining genes have been identified. In addition, the possibility of interspecies breeding is favoured in this group, which arose by alloploidization events, with species ploidy ranging from 2 n = 2 x = 20 in X. tropicalis (the only diploid representative of the genus) to 2 n = 12 x = 108 in X. ruwenzoriensis . To study how two sex-determining genes interact in vivo , X. laevis × X. tropicali s hybrids were produced. Gonadal differentiation in these hybrids revealed that the dm-w gene is dominant over X. tropicalis male-determining sex chromosomes (Y or Z), even though the Y chromosome is dominant in X. tropicalis (Y > W>Z). In the absence of the dm-w gene (the Z chromosome from X. laevis is present), the W chromosome from X. tropicalis is able to trigger ovarian development. Testicular differentiation will take place in the absence of W chromosomes from any of the parental species. The dominance/recessivity relationships between these sex-determining loci in the context of either parental genome remains unknown. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)’.

scholarly journals Opossum milk IgG is from maternal circulation and timing of transfer correlates with neonatal immune development

2019 ◽  
Vol 31 (7) ◽  
pp. 1246 ◽  
Author(s):  
Bethaney D. Fehrenkamp ◽  
Kimberly A. Morrissey ◽  
Robert D. Miller
Keyword(s):  
Milk Composition ◽  
Fc Receptor ◽  
Monodelphis Domestica ◽  
Maternal Circulation ◽  
Immune Development ◽  
Heavy Chains ◽  
Parallel Increase ◽  
Neonatal Immune System ◽  
Changing Patterns ◽  
Marsupial Species

Marsupials, with short gestation times, have more complex and changing patterns of milk composition than eutherians. Maternal immunoglobulins (Ig) that confer immunity on offspring are among the components that change during marsupial lactation. In the present study we quantified the abundance of mammary transcripts encoding Ig heavy chains and their corresponding transporters in the laboratory opossum Monodelphis domestica. IgA transcripts were the most abundant in opossum mammary and, with IgM, increased in abundance linearly from birth to weaning. Similarly, the Fc receptor for IgA, the poly-Ig receptor, also increased in abundance throughout lactation. There were few transcripts for IgG or IgE within the opossum mammaries. This is in contrast with reports for Australian marsupial species. Transcripts for the Neonatal Fc Receptor (FcRN), which transports IgG, were detected throughout lactation, and opossum milk is known to contain IgG. Therefore, milk IgG is likely to be taken from the maternal circulation, rather than resulting from local production. There is a parallel increase in FcRN in the newborn gut that declines around the time when neonates have matured to the point where they can make their own IgG. These results are consistent with a transfer of maternal Ig that is coordinated with the development of the neonatal immune system.

scholarly journals The unusual rainbow trout sex determination gene hijacked the canonical vertebrate gonadal differentiation pathway

2018 ◽  
Vol 115 (50) ◽  
pp. 12781-12786 ◽  
Author(s):  
Sylvain Bertho ◽  
Amaury Herpin ◽  
Adèle Branthonne ◽  
Elodie Jouanno ◽  
Ayaka Yano ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Differentiation ◽  
Genetic Network ◽  
Transcriptional Networks ◽  
Classical Pathway ◽  
Gonadal Differentiation ◽  
Forkhead Box ◽  
Immune Related Gene ◽  
Single Exception ◽  
New Gene

Evolutionary novelties require rewiring of transcriptional networks and/or the evolution of new gene functions. Sex determination (SD), one of the most plastic evolutionary processes, requires such novelties. Studies on the evolution of vertebrate SD revealed that new master SD genes are generally recruited from genes involved in the downstream SD regulatory genetic network. Only a single exception to this rule is currently known in vertebrates: the intriguing case of the salmonid master SD gene (sdY), which arose from duplication of an immune-related gene. This exception immediately posed the question of how a gene outside from the classical sex differentiation cascade could acquire its function as a male SD gene. Here we show that SdY became integrated in the classical vertebrate sex differentiation cascade by interacting with the Forkhead box domain of the female-determining transcription factor, Foxl2. In the presence of Foxl2, SdY is translocated to the nucleus where the SdY:Foxl2 complex prevents activation of the aromatase (cyp19a1a) promoter in cooperation with Nr5a1 (Sf1). Hence, by blocking a positive loop of regulation needed for the synthesis of estrogens in the early differentiating gonad, SdY disrupts a preset female differentiation pathway, consequently allowing testicular differentiation to proceed. These results also suggest that the evolution of unusual vertebrate master sex determination genes recruited from outside the classical pathway likesdYis strongly constrained by their ability to interact with the canonical gonadal differentiation pathway.

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