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Information Resources on Amphibians & Reptiles
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Toxicity

Boone, M.D., R.D. Semlitsch, J.F. Fairchild, and B.B. Rothermel (2004). Effects of an insecticide on amphibians in large-scale experimental ponds. Ecological Applications 14(3): 685-691. ISSN: 1051-0761.
NAL Call Number: QH540.E23
Descriptors: amphibians, insecticide, effects, experimental ponds, toxicity.

Boone, M.D. and C.M. Bridges (2003). Effects of pesticides on amphibian populations. In: R.D. Semlitsch (Editor), Amphibian Conservation, Smithsonian Books: Washington, DC, p. 152-167. ISBN: 1588341194.
NAL Call Number: QL644.7 .A47 2003
Descriptors: amphibians, effect of pesticides, fertilizer, pesticide pollution.

Cauble, K. and R.S. Wagner (2005). Sublethal effects of the herbicide glyphosate on amphibian metamorphosis and development. Bulletin of Environmental Contamination and Toxicology 75(3): 429-435. ISSN: 0007-4861.
NAL Call Number: RA1270.P35A1
Descriptors: frogs, pollutants, contaminants, glyphosate, toxicity testing, larval development.

Christensen, J.R., C.A. Bishop, J.S. Richardson, B. Pauli, and J. Elliott (2004). Validation of an amphibian sperm inhibition toxicological test method using zinc. Environmental Toxicology and Chemistry 23(12): 2950-2955. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Abstract: Analysis of sperm has been investigated as a possible method to examine the toxicity of environmental contaminants. The amphibian sperm inhibition toxicological test (ASITT) method examines the effects of contaminants on Xenopus laevis (African clawed frog) sperm motility and path trajectories. As part of a preliminary validation of the method, the effects of increasing divalent metal ion, zinc (Zn2+), on X. laevis sperm motility were examined. We hypothesized that Zn2+ concentration would have significant inhibitory effects on percent sperm motility, velocities, and trajectories. The Zn2+ was added to a control solution in concentrations from 0 to 1,417 microg/L. Sperm cells were videotaped at 30 frames per second under x 400 microscope, and percent motility was recorded and paths were mapped by marking the change in position of the sperm head over a period of 1 s. Sperm motility was categorized as progressive, hyperactivated, idle, or nonmotile, and velocities and trajectories were calculated on the basis of x,y coordinates. Increasing Zn2+ concentrations caused a significant exponential decay in percent total motility and progressive motility. Straight-line velocity increased with increasing Zn2+ concentrations. Overall, results suggest that Zn2+ may be interfering with cellular processes, such as cellular respiration, flagellar bending, or ion exchange, thereby inhibiting sperm motility.
Descriptors: amphibian, toad, Xenopus laevis, sperm motility, inhibition, toxicological tests methods, pollutants, zinc, chemical toxicity, reproducibility of results.

Coskun, B., U. Comelekoglu, A. Polat, and F.F. Kaymaz (2004). Evaluation of the toxic effects of cypermethrin inhalation on the frog heart. Ecotoxicology and Environmental Safety 57(2): 220-225. ISSN: 0147-6513.
NAL Call Number: QH545.A1E29
Descriptors: frog heart, toxic effects, cypermethrin inhalation, evaluation.

Edginton, A.N., P.M. Sheridan, G.R. Stephenson, D.G. Thompson, and H.J. Boermans (2004). Comparative effects of pH and Vision herbicide on two life stages of four anuran amphibian species. Environmental Toxicology and Chemistry 23(4): 815-822. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Abstract: Vision, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations.
Descriptors: amphibians, anuran, pH, Vision herbicide effects, two life stages, comparative effects, larval life stages.

Ezhili, N., A.A. Sivakumar, and M. Aruchami (2003). Effect of acid pollution on the haemoglobin and haemotological picture in the frog, Rana hexadactyla (Lesson). Journal of Eco Physiology 6(1/2): 25-32. ISSN: 0972-0413.
Descriptors: amphibians, frog, Rana hexadactyla, acid pollution, effect, hemoglobin, hemotological picture.

Feng, S., Z. Kong, X. Wang, L. Zhao, and P. Peng (2004). Acute toxicity and genotoxicity of two novel pesticides on amphibian, Rana N. Hallowell. Chemosphere 56(5): 457-463. ISSN: 0045-6535.
Descriptors: Rana, frogs, acute toxicity, genotoxicity, imidacloprid, pesticides, DNA damage, RH-5849.

Fenoglio, C., E. Boncompagni, M. Fasola, C. Gandini, S. Comizzoli, G. Milanesi, and S. Barni (2005). Effects of environmental pollution on the liver parenchymal cells and Kupffer-melanomacrophagic cells of the frog Rana esculenta. Ecotoxicology and Environmental Safety 60(3): 259-268. ISSN: 0147-6513.
NAL Call Number: QH545.A1E29
Descriptors: frog, Rana esculenta, water pollution, xenobiotics, toxic substances, liver, hepatocytes, enzyme activity, reactive oxygen species, histochemistry.

Fink, N.E. and A. Salibian (2005). Toxicological studies in adult amphibians: effects of lead. Applied Herpetology 2(3): 311-333 Special Issue. ISSN: 1570-7539.
Descriptors: amphibians, Bufo arenarum, toxicological studies, effects of lead.

Greulich, K. and S. Pflugmacher (2003). Differences in susceptibility of various life stages of amphibians to pesticide exposure. Aquatic Toxicology 65(3): 329-336. ISSN: 0166-445X.
NAL Call Number: QH541.5.W3A6
Abstract: Pesticide exposure is discussed as one of the adverse factor that causes impairment of amphibian larval development. Susceptibility of tadpoles to pesticide exposure differs depending on the developmental stages at which individuals are contaminated. This study focused on the influence of the pyrethroid insecticide cypermethrin on the hatching success, mortality and deformities in further development, duration of metamorphosis, and growth of Rana arvalis tadpoles exposed at various life stages. Eggs were harmed significantly by exposure to different concentrations of a-cypermethrin dependent on exposure time. Amphibian embryos hatched with apparent abnormalities indicate insufficient protection by the jelly coat surrounding the embryo. Exposed individuals exhibited typical signs of cyano pyrethroid poisoning (twisting, writhing, abnormal swimming). During the life-stage treatments the observed morphological deformities and behavioral abnormalities lead mostly to death of the tadpoles in later development. Individuals exposed to a-cypermethrin in early life stages (as eggs or newly hatched tadpoles) metamorphosed earlier than in the corresponding control. However, exposure of the tadpoles throughout their whole development prolonged the metamorphosis. These metamorphs were distinguished by a much more compact physique (significant reduction in length and significant increase in weight compared to the corresponding control) so as to resist the adverse conditions. Observed effects of a-cypermethrin exposure on various life stages of R. arvalis tadpoles refer to the danger potential of this insecticide for amphibian development. Any kind of deformation influences the physiological fitness of the individuals (e.g. increased vulnerability to predation). Diminished hatching success, delays in metamorphosis and body growth impact negatively on the viability of amphibian populations in the long term. In combination with other anthropogenic influences (destruction or dissipation of habitats), these effects can cause the local extinction of amphibian species.
Descriptors: Rana arvalis, cypermethrin, pyrethroid insecticides, toxicity, embryo (animal), ova, hatching, developmental stages, metamorphosis, animal growth, abnormal development, water pollution, insecticide residues.

Gurushankara, H.P., S.V. Krishnamurthy, and V. Vasudev (2007). Effect of Malathion on Survival, Growth, and Food Consumption of Indian Cricket Frog (Limnonectus limnocharis) Tadpoles. Archives of Environmental Contamination and Toxicology 52(2): 251-256. ISSN: 0090-4341.
NAL Call Number: TD172.A7
Abstract: The effects of short-term exposure (28 days) of free-feeding Limnonectus limnocharis (Indian cricket frog) tadpoles to field concentrations of malathion were investigated. This frog species is a major biotic component of the agroecosystems of the Western Ghats (13degrees 18', 75degrees 25' and 13degrees 22', 75degrees 28'), where malathion (diethyl [(dimethoxy phosphino thioyl] butanediote), an organophosphate pesticide, is being used extensively. Although malathion is known to cause nonreversible acetylcholine inhibition and diminishes activity, growth and development in amphibian tadpoles, such data on Indian amphibian species are lacking. In the present study, increments in the following were used to assess such an impact: tadpole growth; increase in total length, body length, tail length, and body weight; and food consumption. The different concentrations of malathion employed were 500, 1000, 1500, 2000, and 3000 (So(Bg L- superscript 1(B. Malathion exposure produced significant effects on all measured parameters. Tadpole survival decreased from 20 to 6 tadpoles, with an increase in concentration followed by a decrease in growth. Food consumption of surviving tadpoles also decreased (0.067 mg.g- superscript 1(B.d- superscript 1(B to 0.0075 mg.g- superscript 1(B.d- superscript 1(B) with increased malathion. Decreased food consumption, growth, and development of L. limnocharis tadpoles with an increase of malathion concentration (within field concentration range) over temporal scale reveal the possible threat to this species in the agroecosystems of the Western Ghats.
Descriptors: cricket frog, Limnonectus limnocharis, tadpoles, malathion, exposure, effects, survival, food consumption, growth, development.

Hayes, T., K. Haston, M. Tsui, A. Hoang, C. Haeffele, and A. Vonk (2002). Feminization of male frogs in the wild. Nature 419(6910): 895-896. ISSN: print: 0028-0836; online: 1476-4687.
NAL Call Number: 472 N21
Descriptors: atrazine, toxicity, Rana pipiens, oogenesis, herbicides, herbicide residues, water pollution, males, sex reversal, testicular, oogenesis, United States.

Hayes, T.B., A. Collins, M. Lee, M. Mendoza, N. Noriega, A.A. Stuart, and A. Vonk (2002). Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses. Proceedings of the National Academy of Sciences of the United States of America 99(8): 5476-5480. ISSN: 0027-8424.
NAL Call Number: 500 N21P
Abstract: Atrazine is the most commonly used herbicide in the U.S. and probably the world. It can be present at several parts per million in agricultural runoff and can reach 40 parts per billion (ppb) in precipitation. We examined the effects of atrazine on sexual development in African clawed frogs (Xenopus laevis). Larvae were exposed to atrazine (0.01-200 ppb) by immersion throughout larval development, and we examined gonadal histology and laryngeal size at metamorphosis. Atrazine (greater than or equal to 0.1 ppb) induced hermaphroditism and demasculinized the larynges of exposed males (greater than or equal to 1.0 ppb). In addition, we examined plasma testosterone levels in sexually mature males. Male X. laevis suffered a 10-fold decrease in testosterone levels when exposed to 25 ppb atrazine. We hypothesize that atrazine induces aromatase and promotes the conversion of testosterone to estrogen. This disruption in steroidogenesis likely explains the demasculinization of the male larynx and the production of hermaphrodites. The effective levels reported in the current study are realistic exposures that suggest that other amphibian species exposed to atrazine in the wild could be at risk of impaired sexual development. This widespread compound and other environmental endocrine disruptors may be a factor in global amphibian declines.
Descriptors: frogs, Xenopus laevis, atrazine, toxicity, hermaphroditism, testosterone, larynx, muscles, sexual development, males, size.

Hopkins, W.A., S.E. DuRant, B.P. Staub, C.L. Rowe, and B.P. Jackson (2006). Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis. Environmental Health Perspectives 114(5): 661-666. ISSN: 0091-6765.
Descriptors: amphibian, Gastrophryne carolinensis, reproduction, contaminanats, embryonic development, maternal transfer.

Khan, M.Z. (2004). Effect of pesticides on amphibians and reptiles. Journal of Experimental Zoology India 7(1): 39-47. ISSN: 0972-0030.
Descriptors: amphibians, reptiles, pesticides effect, fertilizer, pesticides, pollution, Pakistan.

Kiesecker, J.M. (2002). Synergism between trematode infection and pesticide exposure: a link to amphibian limb deformities in nature? Proceedings of the National Academy of Sciences of the United States of America 99(15): 9900-9904. ISSN: print: 0027-8424; online: 1091-6490.
NAL Call Number: 500 N21P
Abstract: The apparently rapid increase in the prevalence of amphibian limb deformities has led to substantial interest from ecologists and public health professionals. Hypotheses proposed to explain the deformities fall into two broad categories: chemical contaminants and trematode infection. Although there are convincing experimental demonstrations that certain factors can lead to some deformities, the causes for recent increases in amphibian malformation remain controversial. Moreover, no experimental studies on amphibian deformities have been conducted in the field, and no studies have attempted to examine the synergistic effects of trematode infection and exposure to chemical contaminants. Here, I present the results of field and laboratory experiments that link increased trematode infection, and increased limb deformities, to pesticide exposure. Field experiments conclusively demonstrated that exposure to trematode infection was required for the development of limb deformities in wood frogs, Rana sylvatica. However, deformities were more common at sites adjacent to agricultural runoff. Laboratory experiments corroborated the association between pesticide exposure and increased infection with pesticide-mediated immunocompetency as the apparent mechanism. Given the conservative contaminant exposure levels used [Environmental Protection Agency (EPA) drinking water standards] and the widespread use of many pesticides, these negative impacts may help to explain pathogen-mediated amphibian declines in many regions.
Descriptors: wood frogs, Rana, trematode infections, Trematoda, water pollution, ponds, runoff, agricultural land, pesticide residues, organochlorine pesticides, organophosphorus pesticides, atrazine, esfenvalerate, limbs (animal), deformities, ribeiroia, telorchis, Pennsylvania.

Mandrillon, A.L. and P. Saglio (2005). Une revue des effet des pesticides sur la morphologie, le comportement et les traits d'histoire de vie des amphibiens. A review of the effects of pesticides on the morphology, behavior and life history of amphibians. Bulletin De La Societe Herpetologique De France 116: 5-29. ISSN: 0754-9962.
Descriptors: amphibians, pesticides, life history effects, behavior, morphology, review.
Language of Text: French; Summary in English and French.

Mann, R.M.E. (2005). Methodological approaches in amphibian toxicology. Applied Herpetology 2(3): 221-353 Special Issue. ISSN: 1570-7539.
Descriptors: amphibians, toxicology, methodological approaches.

Marquis, O., A. Millery, S. Guittonneau, and C. Miaud (2006). Solvent toxicity to amphibian embryos and larvae. Chemosphere 63(5): 889-892. ISSN: 0045-6535.
Abstract: Organic micropollutants are often damaging for aquatic organisms. Being usually hydrophobic compounds, they are often dissolved in an organic co-solvent which increases their solubility in water. The aim of this study was to study the toxicity of various solvents on embryos (protected or not by jelly coat) and on tadpoles of the common frog (Rana temporaria). Tested solvents were methanol (MeOH), methylene chloride (CH(2)Cl(2)), dimethyl sulfoxyde (DMSO), acetone (Ac) and ethanol (EtOH). Embryos exhibited higher mortality rates than tadpoles. Embryos with jelly were more sensitive to high concentration of solvents than embryos without jelly (except for acetone). According to these results, Ac, DMSO and CH(2)Cl(2) can be used as co-solvents in water to help the dissolution of micropollutants at concentration equal to or lower than 0.001 ml/l for frog embryos, and EtOH, Ac and CH(2)Cl(2) at concentration equal to or lower than 0.01 ml/l for Rana temporaria tadpoles.
Descriptors: frog, Rana temporaria, embryonic development drug effects, environmental pollutants toxicity, larva drug effects, solvents toxicity, embryo loss chemically induced, petrolatum pharmacology.

Mautz, W.J. and M.R. Dohm (2004). Respiratory and behavioral effects of ozone on a lizard and a frog. Comparative Biochemistry and Physiology. Part A, Molecular and Integrative Physiology 139(3): 371-377. ISSN: 1095-6433.
Abstract: Ozone at concentrations found in urban air pollution is known to have significant physiological effects on humans and other mammals. Exposure of the lizard, Sceloporus occidentalis, to 0.6 ppm ozone for 4 h at 25 degrees C induced 1.6 degrees C of behavioral hypothermia immediately following exposure, but selected body temperature recovered to control 35.3 degrees C the next day. Lizards exposed at 35 degrees C to 0.6 ppm ozone for 4 h selected body temperatures 1.9 degrees C below controls after exposure, and the behavioral hypothermic response persisted and increased to 3.3 degrees C the following day. Four-hour exposures of the frog, Pseudacris cadaverina, to 0.2 to 0.8 ppm ozone resulted in concentration-dependent alterations of respiration including depression of lung ventilation and oxygen consumption and the adoption of a low profile posture that reduced the exposed body surface. Ozone levels in wilderness habitats downwind of urban sources can potentially have stressful physiological effects on wildlife. Defensive physiological and behavioral reactions to ozone exposure may interfere with routine activities, and oxidant air pollution may be in part responsible for observed wildlife population declines.
Descriptors: lizard, Sceloporus occidentalis, frog, Pseudacris cadaverina, ozone, behavioral effects, respiratory effects, air pollution, stressful effects.

McDaniel, T.V., P.A. Martin, N. Ross, S. Brown, S. Lesage, and B.D. Pauli (2004). Effects of chlorinated solvents on four species of North American amphibians. Archives of Environmental Contamination and Toxicology 47(1): 101-109. ISSN: 0090-4341.
NAL Call Number: TD172.A7
Descriptors: amphibians, chlorinated solvents, effects, four species, tetrachlorethylene, North American, pollution, ground water.

Mouchet, F., L. Gauthier, C. Mailhes, V. Ferrier, and A. Devaux (2005). Comparative study of the comet assay and the micronucleus test in amphibian larvae (Xenopus laevis) using benzo(a)pyrene, ethyl methanesulfonate, and methyl methanesulfonate: establishment of a positive control in the amphibian comet assay. Environmental Toxicology 20(1): 74-84. ISSN: 1520-4081.
NAL Call Number: RA1221.T69
Descriptors: frogs, Xenopus laevis, pollutants, genotoxicity, biomarkers, toxicity testing, bioassays, DNA damage, screening, dose response.

Ortiz Santaliestra, M.E., A. Marco, M.J. Fernandez, and M. Lizana (2006). Influence of developmental stage on sensitivity to ammonium nitrate of aquatic stages of amphibians. Environmental Toxicology and Chemistry 25(1): 105-111. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Descriptors: amphibians, develpmental stage, influence, sensitivity, ammonium nitrate, aquatic stages, effect, embryonic, larval.

Orton, F., J.A. Carr, and R.D. Handy (2006). Effects of nitrate and atrazine on larval development and sexual differentiation in the northern leopard frog Rana pipiens. Environmental Toxicology and Chemistry 25(1): 65-71. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Descriptors: leopard frog, Rana pipiens, sexual differentiation, larval development, nitrate and atrazine, exposure effects.

Osano, O., W. Admiraal, and D. Otieno (2002). Developmental disorders in embryos of the frog Xenopus laevis induced by chloroacetanilide herbicides and their degradation products. Environmental Toxicology and Chemistry 21(2): 375-379. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Descriptors: frog, Xenopus laevis, alachlor, metolachlor, toxicity, animal diseases, embryotoxicity, teratogenesis, derivatives.

Papaefthimiou, C., M.G. Cabral, C. Mixailidou, C.A. Viegas, I. Sa Correia, and G. Theophilidis (2004). Comparison of two screening bioassays, based on the frog sciatic nerve and yeast cells, for the assessment of herbicide toxicity. Environmental Toxicology and Chemistry 23(5): 1211-1218. ISSN: 0730-7268.
NAL Call Number: QH545.A1E58
Abstract: Two different test systems, one based on the isolated sciatic nerve of an amphibian and the other on a microbial eukaryote, were used for the assessment of herbicide toxicity. More specifically, we determined the deleterious effects of increasing concentrations of herbicides of different chemical classes (phenoxyacetic acids, triazines, and acetamides), and of 2,4-dichlorophenol (2,4-DCP), a degradation product of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), on electrophysiological parameters and the vitality of the axons of the isolated sciatic nerve of the frog (Rana ridibunda) and on the growth curve of the yeast Saccharomyces cerevisiae based on microtiter plate susceptibility assays. The no-observed-effect-concentration (NOEC), defined as the maximum concentration of the tested compound that has no effect on these biological parameters, was estimated. In spite of the different methodological approaches and biological systems compared, the NOEC values were identical and correlated with the lipophilicity of the tested compounds. The relative toxicity established here, 2,4-DCP > alachlor, metolachlor >> metribuzin > 2,4-D, 2-methyl-4-chlorophenoxyacetic acid (MCPA), correlates with the toxicity indexes reported in the literature for freshwater organisms. Based on these results, we suggest that the relatively simple, rapid, and low-cost test systems examined here may be of interest as alternative or complementary tests for toxicological assessment of herbicides.
Descriptors: Rana, frog, sciatic nerve, yeast cells, herbicide toxicity, screening bioassays, comparison, amphibian.

Pettersson, I., A. Arukwe, K. Lundstedt Enkel, A. Mortensen, and C. Berg (2006). Persistent sex-reversal and oviducal agenesis in adult Xenopus (Silurana) tropicalis frogs following larval exposure to the environmental pollutant ethynylestradiol. Aquatic Toxicology 79(4): 356-365. ISSN: 0166-445X.
NAL Call Number: QH541.5.W3A6
Abstract: It is known that estrogen-like environmental pollutants can feminise gonadal differentiation in frogs resulting in female-biased sex-ratios at metamorphosis. The long-term effects on reproductive function in frogs following larval exposure to pollutants are less known. Amphibian test systems which allow life-cycle studies are therefore needed. The aim of the present study was to characterise long-term estrogenic effects on the reproductive system of the emerging model species Xenopus (Silurana) tropicalis following larval exposure to ethynylestradiol (EE2). EE2 is a synthetic estrogen that has been detected in sewage effluents and in surface waters. Newly hatched tadpoles (Niewkoop Faber (NF) stage 48) were exposed to the nominal EE2 concentrations 0 (control), 1, 10, and 100 nM (with analytical chemistry support) until complete metamorphosis (NF stage 66). Effects on the reproductive organs were determined in juveniles (1 month after metamorphosis) and in 9-month-old frogs. Larval exposure to EE2 caused female-biased phenotypic sex-ratios in both juvenile and adult frogs, which is in agreement with previous work on other frog species. Nearly all (97%) of the 63 EE2-exposed 9-month-old frogs had ovaries. Histological evaluation of the gonads of the 9-month-old frogs showed that they were sexually mature. Among the adult frogs with ovaries there was a dose-dependent increase in the frequency of individuals lacking oviducts. Adult frogs exposed to 100 nM EE2 that had ovaries but no oviducts had lower levels of estrogen receptor alpha (ER(Sa(Ba) mRNA in the brain than control animals and those exposed to 100 nM EE2 that had ovaries as well as oviducts. EE2 exposure did not cause any significant changes in ER(Sa(Ba mRNA levels in the ovaries of the adult frogs. The reduced level of ER(Sa(Ba mRNA in the brain of individuals with ovaries lacking oviducts suggests an organizing effect of EE2 on the central nervous system. The results show that transient early life-stage exposure to an environmental pollutant can induce effects on the reproductive organs and the central nervous system that persist into adulthood. Overall, our data suggest that X. tropicalis, which has a shorter generation time than the well-established model species Xenopus laevis, is a suitable model organism for research on developmental reproductive toxicity in anuran species.
Descriptors: Xenopus tropicalis, frogs, water pollution, pollutants, estradiol, long term effects, animal models, toxicity testing, oviducts, reproductive toxicology, messenger RNA, hormone receptors, histology, animal morphology.

Pickford, D.B. and I.D. Morris (2003). Inhibition of gonadotropin-induced oviposition and ovarian steroidogenesis in the African clawed frog (Xenopus laevis) by the pesticide methoxychlor. Aquatic Toxicology 62(3): 179-194. ISSN: 0166-445X.
NAL Call Number: QH541.5.W3A6
Abstract: Concern over the role of environmental toxicants in amphibian population declines has highlighted the need to develop more comprehensive ecotoxicological test methods for this at-risk group. With continued interest in environmental endocrine disrupters (EDs), and the paucity of data pertaining to endocrine disrupting effects in amphibia, such tests should incorporate reproductive and endocrine endpoints. We investigated the effects of in vivo exposure to the pesticide methoxychlor (MXC) on reproductive and endocrine function in adult female African clawed frogs, (Xenopus laevis). Frogs were exposed to MXC (0.5-500 micrograms/l) in tank water throughout a cycle of oogenesis stimulated by exogenous gonadotropins. Gonadotropin-induced oviposition was delayed, and reduced numbers of unfertilizable eggs of increased size were oviposited by frogs exposed to 500 micrograms/l MXC. Reduced egg output was mirrored by increased gonado-somatic index in MXC-treated frogs. Post-oviposition, plasma sex steroid profiles were altered in MXC-exposed frogs as estradiol/progesterone and estradiol/testosterone ratios were elevated. Ex vivo synthesis of progesterone by ovarian explants was significantly reduced for frogs exposed to MXC > or = to 0.5 micrograms/l. Additionally, plasma vitellogenin concentrations were significantly depressed in frogs exposed to 500 micrograms/l MXC. These data indicate that reproductive and endocrine dysfunction can occur in adult amphibia exposed to high concentrations of an environmental toxin with endocrine disrupting activity. Such effects may be indicative of the potential for adverse effects on amphibian wildlife exposed to environmental EDs.
Descriptors: African clawed frog, Xenopus laevis, methoxychlor, insecticides, toxicity, oviposition, steroidogenesis, ovaries, gonadotropins, estradiol, progesterone, testosterone, blood plasma, ova, gonadosomatic index, vitellogenins, ratios.

Relyea, R.A., N.M. Schoeppner, and J.T. Hoverman (2005). Pesticides and amphibians: the importance of community context. Ecological Applications 15(4): 1125-1134. ISSN: 1051-0761.
NAL Call Number: QH540.E23
Descriptors: malathion, insecticide residues, glyphosate, herbicide residues, ecotoxicology, toxicity, Hyla, Bufo americanus, Rana pipiens, developmental stages, adult animals, food webs, community ecology, predators, predator prey relationships, water pollution, Dytiscidae, aquatic organisms, Dytiscus, Notophthalmus viridescens, eastern newt.

Relyea, R. (2005). The lethal impact of roundup on aquatic and terrestrial amphibians. Ecological Applications 15(4): 1118-1124. ISSN: 1051-0761.
NAL Call Number: QH540.E23
Descriptors: glyphosate, herbicide residues, toxicity, amphibians, Rana pipiens, Bufo americanus, Hyla versicolor, adult animals, developmental stages, ecotoxicology, soil pollution, water pollution, adsorption, loam soils, sand.

Roy, D. (2002). Amphibians as environmental sentinels. Journal of Biosciences 27(3): 187-188. ISSN: 0250-5991.
Online: http://www.ias.ac.in/jbiosci/jun2002/187.pdf
NAL Call Number: QH1.J63
Descriptors: amphibians, environmental sentinals, pollution, toxic chemicals, contamination.

Sampath, K., I.J.J. Kennedy, and R. James (2002). Pesticide impact on excretory physiology of the common frog, Rana tigrina (Daud) tadpoles. Bulletin of Environmental Contamination and Toxicology 68(5): 652-659. ISSN: print: 0007-4861; online: 1432-0800.
NAL Call Number: RA1270.P35A1
Descriptors: toxicity, frog, Rana tigrina, tadpoles, pesticide impact, excretory physiology.

Sanzo, D. and S.J. Hecnar (2006). Effects of road de-icing salt (NaCl) on larval wood frogs (Rana sylvatica). Environmental Pollution 140(2): 247-256. ISSN: 0269-7491.
NAL Call Number: QH545.A1E52
Descriptors: larval wood frog, Rana sylvatica, road de-icing salt, chemical pollution, effects.

Song, M.O., D.J. Fort, D.L. Mclaughlin, R.L. Rogers, J.H. Thomas, B.O. Buzzard, A.M. Noll, and N.K. Myers (2003). Evaluation of Xenopus tropicalis as an alternative test organism for frog embryo teratogenesis assay: Xenopus (fetax). Drug and Chemical Toxicology 26(3): 177-189. ISSN: print: 0148-0545; online: 1525-6014.
NAL Call Number: QP901.D7
Descriptors: amphibians, Xenopus tropicalis, frog embryo, teratogenesis assay, test organism, alternative, evaluation, ICCVAM.

Sparling, D.W. and G. Harvey (2006). Comparative toxicity of ammonium and perchlorate to Amphibians. Bulletin of Environmental Contamination and Toxicology 76(2): 210-217. ISSN: print: 0007-4861; online: 1432-0800.
NAL Call Number: RA1270.P35A1
Descriptors: amphibians, ammonium, perchlorate, comparative toxicity, contamination, environment.

Steinberg, C.E.W., S. Hoss, W. Kloas, I. Lutz, T. Meinelt, S. Pflugmacher, and C. Wiegand (2004). Hormonelike effects of humic substances on fish, amphibians, and invertebrates. Environmental Toxicology 19(4): 409-411. ISSN: print: 1520-4081; online: 1522-7278.
NAL Call Number: RA1221.T69
Descriptors: amphibians, fish, invertebrates, humic substances, hormonelike effects, toxicity.
Notes: In the special issue: 11th International Symposium on Toxicity Assessment / edited by L. Manusadzianas. Includes references.

 

 

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