Developmental alterations as a result of in ovo exposure to the pesticide metabolite p,p′-DDE in Alligator mississippiensis

Milnes, Matthew R.; Bryan, Teresa A.; Medina, Jennifer Gates; Gunderson, Mark P.; Guillette, Louis J.

doi:10.1016/j.ygcen.2005.06.013

Cited by 58 publications

(44 citation statements)

References 30 publications

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“…Eggs were collected from Lake Orange (FL, USA) and were incubated and maintained as described previously (Milnes et al 2005). Egg yolk was collected at developmental stage 19 and was stored at K80 8C to use in the development of the VTG assay.…”

Section: Animals and Samplingmentioning

confidence: 99%

The reproductive hormone cycle of adult female American alligators from a barrier island population

Hamlin

Lowers²,

Kohno

et al. 2014

Reproduction

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Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17b-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.

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Section: Animals and Samplingmentioning

confidence: 99%

The reproductive hormone cycle of adult female American alligators from a barrier island population

Hamlin

Lowers²,

Kohno

et al. 2014

Reproduction

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“…Thus, reptiles are sensitive to environmental factors, such as climate change and exposure to endocrine disrupting compounds [Hamlin and Guillette, 2011]. Indeed, in ovo exposure studies have demonstrated that sex ratios of American alligators (Alligator mississippiensis) [Milnes et al, 2005] and redeared sliders (Trachemys scripta) [Willingham and Crews, 1999] are sensitive to environmental contaminants with endocrine disrupting activity (EDCs). Here, we review reptilian gonadogenesis with an emphasis on environmental aspects.…”

mentioning

confidence: 99%

Gonadal Differentiation in Reptiles Exhibiting Environmental Sex Determination

Kohno¹,

Parrott²,

Yatsu³

et al. 2014

Sex Dev

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As temperature-dependent sex determination (TSD) and homozygote or heterozygote genetic sex determination (GSD) exist in multiple reptilian taxa, they represent sex determination systems that have emerged de novo. Current investigations have revealed that the genetic mechanisms used by various reptilian species are similar to those used by other vertebrates. However, the recent completion or near completion of various reptilian genome projects suggests that new studies examining related species with and without TSD could begin to provide additional insight into the evolution of TSD and GSD in vertebrate ancestors. Major questions still remain concerning germ cell migration and specification, the differentiation of gonadal accessory cells, such as the Sertoli cells and granulosa cells of the developing testis and ovary, respectively, and the mechanisms by which gene expression is regulated during TSD events. Further, reptilian sentinels and their mechanisms of gonadogenesis will likely remain important indicator species for environmental health. Thus, ongoing and new investigations need to tie molecular information to gonadal morphogenesis and function in reptiles. Such data will not only provide important information for an understanding of the evolution of these phenomena in vertebrates, but could also provide an important understanding of the health of the environment around us.

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“…There is much basis for inferring concern about reproductive performance, based mainly on information from the USA, Argentina, and Mexico (Guillette et al, 1994(Guillette et al, , 1995Milnes et al, 2005;Rauschenberger et al, 2007;Stoker et al, 2011;Woodword et al, 2011;Gonzalez-Jauregui et al, 2012). There is also concern about changes in behaviour (Clotfelter et al, 2004;Zala and Penn, 2004;Gonzalez-Jauregui et al, 2012) and gene-pollutant interactions (Moore et al, 2012).…”

Section: Relationship To Mortalities and Possible Other Effectsmentioning

confidence: 99%

Chlorinated, brominated, and fluorinated organic pollutants in Nile crocodile eggs from the Kruger National Park, South Africa

Bouwman

Booyens

Govender

et al. 2014

Ecotoxicology and Environmental Safety

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a b s t r a c tRepeated annual episodes of Nile crocodile deaths in two isolated areas of the Kruger National Park prompted the investigation of possible organohalogen pollutant involvement. Crocodile eggs were collected close to one of the mortality sites (Gorge) as well as from a crocodile farm (CF) as reference. ∑DDT was significantly higher in Gorge (450 ng/g wm) than in CF eggs (85 ng/g wet mass). Percentage DDT of ∑DDT was significantly higher in CF (14 per cent) than in Gorge eggs (5 per cent). Mean ∑DDT was almost 70 times higher than mean ∑PCB in Gorge eggs. HCB, β-HCH, mirex, brominated flame retardants (BFRs), and perfluorinated compounds (PFCs) occurred at lower concentrations. We believe that the BFR and PFCs data represent the first published results for any crocodile egg. Thickening of the outer eggshell layer of Gorge eggs was significantly associated with higher concentrations of ∑DDT. Concentrations of ∑DDT and other pollutants were in the same range as eggs from elsewhere, where there were no mortalities. Concentrations of ∑DDT in eggs from healthy Australian crocodiles were of the same orders of magnitude as the current study, making it highly unlikely that the concentrations of pollutants measured in the present study would have caused or substantially contributed towards the mortalities observed. Concerns about reproduction and behaviour remain. As large predators, crocodilians are at the apex of the freshwater aquatic food web. More research is needed to guide measures to manage African freshwater systems so that it will also sustainably accommodate these large, long-lived animals.

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Developmental alterations as a result of in ovo exposure to the pesticide metabolite p,p′-DDE in Alligator mississippiensis

Cited by 58 publications

References 30 publications

The reproductive hormone cycle of adult female American alligators from a barrier island population

The reproductive hormone cycle of adult female American alligators from a barrier island population

Gonadal Differentiation in Reptiles Exhibiting Environmental Sex Determination

Chlorinated, brominated, and fluorinated organic pollutants in Nile crocodile eggs from the Kruger National Park, South Africa

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