Parental Exposure to Pesticides and Poor Clutch Viability in American Alligators

Rauschenberger, R. Heath; Wiebe, Jon J.; Sepúlveda, Marı́a S.; Scarborough, Janet E.; Gross, Timothy S.

doi:10.1021/es0628194

Cited by 50 publications

(33 citation statements)

References 13 publications

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“…Adults that had been exposed to synthetic compounds over a lifetime of feeding in contaminated areas experienced endocrinological abnormalities (Guillette et al 1994) and reduced clutch success (Rauschenberger et al 2007). Offspring that succeeded in hatching frequently experienced retarded development and growth and reduced reproductive potential (Guillette et al 1994, Gunderson et al 2004, Milnes et al 2005.…”

Section: Physiological and Reproductive Traits And Risks Of Contaminamentioning

confidence: 99%

“The Calamity of So Long Life”: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates

Rowe¹

2008

BioScience

106

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Articles Reproductive fitness, the probability that an individual will produce viable offspring of equal or greater replacement value, provides an avenue by which environmental influences on individuals transcend to population and higher-order phenomena. Life history strategies represent the suite of traits that optimize reproductive fitness of individuals within the environmental and phylogenetic constraints imposed on the species during its evolutionary history. A species' life history strategy is shaped by trade-offs among alternative, attainable expressions of traits, including (but not limited to) life span; time to maturation; number of lifetime breeding events; and parental investment in offspring number, size or energy content, or care (Stearns 1989, Congdon et al. 2001. The combination of traits and the specific expressions that optimize fitness are unique to a species, yet have classically been broadly categorized as "r-selected" or "K-selected" life history strategies (Pianka 1970). While these categorizations represent theoretical extremes bounding a vast diversity of trait combinations found in nature, and thus no realized life history strategy represents an "ideal" r-or K-selected strategy, the categorizations are conceptually useful for broadly assessing potential environmental influences on fitness resulting from a particular life history strategy.Species that possess r-selected strategies tend to be opportunistic, short-lived, rapid to mature, and semelparous (breeding only once), producing large numbers of small offspring. Such species typically exploit rapidly changing environmental conditions and are capable of establishing populations quickly in novel environments (Pianka 1970). Relative to r-selected species, those employing K-selected life history strategies are long-lived, slow to mature, iteroparous (breeding multiple times), and typically make large per capita parental investments in few offspring during a given breeding event (Pianka 1970). This life history strategy is optimized for environmental conditions that on average are relatively stable over an individual's long reproductive lifetime, yet it is resilient to periodic, stochastic fluctuations in habitat quality that may compromise a given breeding event (a "bet-hedging" strategy; Stearns 1976).Persistent, synthetic contaminants were developed and have been used widely only in the past century, yet already their use has resulted in contamination of habitats on a global scale (e.g., Schwarzenbach et al. 2006). Synthetic compounds such as organochlorine pesticides, polychlorinated biphenyls (PCBs), and brominated fire retardants (brominated diphenyl ethers, or BDEs) can persist in the environment for decades, Christopher L. Rowe (e-mail: rowe@cbl.umces.edu

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Section: Physiological and Reproductive Traits And Risks Of Contaminamentioning

confidence: 99%

“The Calamity of So Long Life”: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates

Rowe¹

2008

BioScience

106

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“…They may be additionally exposed to the demethylated metabolites through ingestion of MXC-exposed prey organisms that have biotransformed MXC. Recent studies have reported parent MXC concentrations of 0.7 ng/g in seafood from Southern China (Guo et al, 2007), between <0.35 ng/g (limit of detection) and 2 ng/g in freshwater fish captured in the Colorado river (Hinck et al, 2007), between 8 and 17 ng/g in alligator eggs from central Florida lakes (Rauschenberger et al, 2007) and 534 ng/g in fat from crocodile scute in Costa Rica (Rainwater et al, 2007). MXC was found in 5 of 36 soil samples taken from agricultural areas in British Columbia, and the average MXC concentration in these samples was 0.23 mg/ kg (Wan et al, 2005).…”

Section: Comparisons Of Conjugation and Demethylation Pathwaysmentioning

confidence: 99%

Glucuronidation and sulfonation, in vitro, of the major endocrine-active metabolites of methoxychlor in the channel catfish, Ictalurus punctatus, and induction following treatment with 3-methylcholanthrene

2008

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The organochlorine pesticide, methoxychlor (MXC), is metabolized in animals to phenolic monoand bis-demethylated metabolites (OH-MXC and HPTE respectively) that interact with estrogen receptors and may be endocrine disruptors. The phase II detoxication of these compounds will influence the duration of action of the estrogenic metabolites, but has not been investigated extensively. In this study, the glucuronidation and sulfonation of OH-MXC and HPTE were investigated in subcellular fractions of liver and intestine from untreated, MXC-treated and 3-methylcholanthrene (3-MC)-treated channel catfish, Ictalurus punctatus. MXC-treated fish were given i.p. injections of 2 mg MXC/kg daily for 6 days and sacrificed 24 hr after the last dose. The 3-MC treatment was a single 10 mg/kg i.p. dose 5 days prior to sacrifice. In hepatic microsomes from control fish, the V max value (mean ± S.D., n=4) for glucuronidation of OH-MXC was 270 ± 50 pmol/ min/mg protein, higher than found for HPTE (110 ± 20 pmol/min/mg protein). For each substrate, the V max values observed in intestinal microsomes were approximately twice those found in the liver. The K m values for OH-MXC and HPTE glucuronidation in control liver were not significantly different and were 0.32 ± 0.04 mM for OH-MXC and 0.26 ± 0.06 mM for HPTE. The K m for the co-substrate, UDPGA, was higher in liver (0.28 ± 0.09 mM) than intestine (0.04 ± 0.02 mM). Treatment with 3-MC but not MXC increased the V max for glucuronidation in liver and intestine. Glucuronidation was a more efficient pathway than sulfonation for both substrates, in both tissues. The V max values for sulfonation of OH-MXC and HPTE respectively in liver cytosol were 7 ± 3 and 17 ± 4 pmol/min/mg protein and in intestinal cytosol were 13 ± 3 and 30 ± 5 pmol/min/mg protein. Treatment with 3-MC but not MXC increased rates of sulfonation of OH-MXC and HPTE and the model substrate, 3-hydroxy-benzo(a)pyrene in both intestine and liver. Comparison of the kinetics of the conjugation pathways with those published for the demethylation of MXC showed that formation of the endocrine-active metabolites was more efficient than either conjugation pathway. Residues of OH-MXC and HPTE were detected in extracts of liver microsomes from MXC-treated fish. This work showed that although OH-MXC and HPTE could be eliminated by glucuronidation and sulfonation, the phase II pathways were less efficient than the phase I pathway leading to formation of these endocrine-active metabolites.

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“…Alligators living in Lake Apopka, Florida, undergo a combinatorial exposure to high levels of pesticides and agricultural contamination compared with those alligators living in a nearby, but relatively pristine lake, Lake Woodruff (Heinz et al 1991, Guillette et al 1999, Rauschenberger et al 2007. A number of reproductive abnormalities, including altered gonadal development and decreased robustness of sexually dimorphic gene expression, have been reported in alligators originating from Lake Apopka (Milnes et al 2005(Milnes et al , 2008).…”

Section: Introductionmentioning

confidence: 99%

Influence of tissue, age, and environmental quality on DNA methylation in Alligator mississippiensis

Parrott¹,

Bowden²,

Kohno³

et al. 2014

Reproduction

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Epigenetic modifications are key mediators of the interactions between the environment and an organism's genome. DNA methylation represents the best-studied epigenetic modification to date and is known to play key roles in regulating transcriptional activity and promoting chromosome stability. Our laboratory has previously demonstrated the utility of the American alligator (Alligator mississippiensis) as a sentinel species to investigate the persistent effects of environmental contaminant exposure on reproductive health. Here, we incorporate a liquid chromatography-tandem mass spectrometry method to directly measure the total (global) proportion of 5-methyl-2 0 -deoxycytidine (5mdC) in ovarian and whole blood DNA from alligators. Global DNA methylation in ovaries was significantly elevated in comparison with that of whole blood. However, DNA methylation appeared similar in juvenile alligators reared under controlled laboratory conditions but originating from three sites with dissimilar environmental qualities, indicating an absence of detectable site-of-origin effects on persistent levels of global 5mdC content. Analyses of tissues across individuals revealed a surprising lack of correlation between global methylation levels in blood and ovary. In addition, global DNA methylation in blood samples from juvenile alligators was elevated compared with those from adults, suggesting that age, as observed in mammals, may negatively influence global DNA methylation levels in alligators. To our knowledge, this is the first study examining global levels of DNA methylation in the American alligator and provides a reference point for future studies examining the interplay of epigenetics and environmental factors in a long-lived sentinel species.

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Parental Exposure to Pesticides and Poor Clutch Viability in American Alligators

Cited by 50 publications

References 13 publications

“The Calamity of So Long Life”: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates

“The Calamity of So Long Life”: Life Histories, Contaminants, and Potential Emerging Threats to Long-lived Vertebrates

Glucuronidation and sulfonation, in vitro, of the major endocrine-active metabolites of methoxychlor in the channel catfish, Ictalurus punctatus, and induction following treatment with 3-methylcholanthrene

Influence of tissue, age, and environmental quality on DNA methylation in Alligator mississippiensis

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