Degeneration of germ line cells in amphibian ovary

Ogielska, Maria; Rozenblut, Beata; Augustyńska, Renata; Kotusz, Agnieszka

doi:10.1111/j.1463-6395.2009.00411.x

Cited by 19 publications

(24 citation statements)

References 23 publications

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“…Only a portion of the developing oocytes reach final maturity; the remaining ones undergo atresia (i.e., degeneration and resorption). The balance between the numbers of mature and atretic oocytes is important for controlling the fecundity in amphibians and fish [36,37].…”

Section: Introductionmentioning

confidence: 99%

Disrupted Oogenesis in the Frog Xenopus tropicalis after Exposure to Environmental Progestin Concentrations1

Säfholm

Norder

Fick

et al. 2012

Biology of Reproduction

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Levonorgestrel is a synthetic progesterone commonly used in pharmaceuticals (e.g., in contraceptives). It is found in sewage treatment plant effluents at concentrations up to 30 ng/L and was recently shown to pose a threat to egg laying in fish. Information on the susceptibility of adult amphibians to progestin toxicity is lacking. The present study aimed to 1) characterize progestogenic effects on the full cycle of oogenesis (egg development) in frogs and 2) determine female amphibians' susceptibility to reproductive impacts from progestogenic compounds in the environment. Sexually mature female Xenopus tropicalis were exposed to levonorgestrel via the surrounding water for 7 days (0, 51, or 307 ng/L) or 28 days (0, 1.3, 18, 160, or 1240 ng/L). Their ovaries were analyzed histologically with respect to frequencies of immature (in early meiotic prophase I), previtellogenic, vitellogenic, mature, and atretic oocytes. The 28-day exposure caused reduced proportions of oocytes at immature, vitellogenic, and mature stages, and increased proportions of previtellogenic oocytes compared with the control. The lowest tested concentration, 1.3 ng/L, increased the proportions of previtellogenic oocytes and reduced the proportions of vitellogenic oocytes, indicating inhibited vitellogenesis. The present study shows that progestin concentrations found in the aquatic environment impaired oogenesis in adult frogs. Our results indicate that progestogenic effects on oocyte development include interrupted germ cell progression into meiosis and inhibited vitellogenesis. Considering the crucial role of oogenesis in female fertility, our results indicate that progestogenic pollutants may pose a threat to reproduction in wild amphibian populations.

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Section: Introductionmentioning

confidence: 99%

Disrupted Oogenesis in the Frog Xenopus tropicalis after Exposure to Environmental Progestin Concentrations1

Säfholm

Norder

Fick

et al. 2012

Biology of Reproduction

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“…Images were acquired by a cooled Carl Zeiss AxioCam HRc CCD camera. Histological analysis of gonads and evaluation of degeneration of diplotene oocytes and spermatogonia in developing gonads were done according to protocols published by Ogielska and Kotusz [2004], Ogielska et al [2010] and Haczkiewicz and Ogielska [2013].…”

Section: Determination Of Phenotypic Sex and Dna Extractionmentioning

confidence: 99%

Maintenance of Ancestral Sex Chromosomes in Palearctic Tree Frogs: Direct Evidence from <b><i>Hyla orientalis</i></b>

Stöck

Savary²,

Zaborowska³

et al. 2013

Sex Dev

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Contrasting with the situation found in birds and mammals, sex chromosomes are generally homomorphic in poikilothermic vertebrates. This homomorphy was recently shown to result from occasional X-Y recombinations (not from turnovers) in several European species of tree frogs (Hyla arborea, H. intermedia and H. molleri). Because of recombination, however, alleles at sex-linked loci were rarely diagnostic at the population level; support for sex linkage had to rely on multilocus associations, combined with occasional sex differences in allelic frequencies. Here, we use direct evidence, obtained from anatomical and histological analyses of offspring with known pedigrees, to show that the Eastern tree frog (H. orientalis) shares the same pair of sex chromosomes, with identical patterns of male heterogamety and complete absence of X-Y recombination in males. Conservation of an ancestral pair of sex chromosomes, regularly rejuvenated via occasional X-Y recombination, seems thus a widespread pattern among Hyla species. Sibship analyses also identified discrepancies between genotypic and phenotypic sex among offspring, associated with abnormal gonadal development, suggesting a role for sexually antagonistic genes on the sex chromosomes.

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“…Moreover, by skeletochronological technique (Smirina, ) it is relatively easy to estimate female current age, as well as age of her sexual maturity. The development of ovary (Ogielska and Kotusz, ) and degeneration of oocytes (Ogielska et al, ) were already described in this species. Additionally, the original studies by Witschi were done on this (and closely related Rana sylvatica ) species.…”

mentioning

confidence: 78%

A Stockpile of Ova in the Grass Frog Rana temporaria is Established Once for the Life Span. Do Ovaries in Amphibians and in Mammals Follow the Same Evolutionary Strategy?

Ogielska

Kotusz

Augustyńska

et al. 2013

The Anatomical Record

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Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a female. Our quantitative studies show that primary oogonia in adult female frogs can proliferate, but they fail to differentiate further and do not enter meiosis, and thereby there is no supplementation of new generations of oocytes after each spawning. Ovaries of one-year-old grass frogs contain (median) 53,447 diplotene oocytes, in two-years-old frogs this number decreased to 33,583 and eventually reached 25,679 in virgin mature females. More than 50% decrease in the total oocyte number was accompanied by massive degeneration (atresia) of oocytes. The final number of oocytes in a female forms a stock for 11-12 breeding seasons and exceeds the number of eggs produced during the potential reproductive life span of this species. The phylogenetic context of oocyte recruitment modes in the major clades of vertebrates is discussed in respect to their ability to replenish the stock (a renewable stock in ovaries named "open" vs. a non-renewable stock in ovaries named "closed"). Anat Rec,

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Degeneration of germ line cells in amphibian ovary

Cited by 19 publications

References 23 publications

Disrupted Oogenesis in the Frog Xenopus tropicalis after Exposure to Environmental Progestin Concentrations1

Disrupted Oogenesis in the Frog Xenopus tropicalis after Exposure to Environmental Progestin Concentrations1

Maintenance of Ancestral Sex Chromosomes in Palearctic Tree Frogs: Direct Evidence from <b><i>Hyla orientalis</i></b>

A Stockpile of Ova in the Grass Frog Rana temporaria is Established Once for the Life Span. Do Ovaries in Amphibians and in Mammals Follow the Same Evolutionary Strategy?

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