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Abstracts / Toxicology Letters 259S (2016) S73–S247
PP5.8 Elasmobranchs as sentinel species in the Southern Gulf of Mexico
PP5.9 Tributyltin chloride induces imposex in females of the purple snail (Plicopurpura pansa)
V.M. Cobos-Gasca 1 , F. Serrano-Flores 2 , R.C. Barrientos-Medina 1 , J.A. Navarro-Alberto 1 , J. Rendón von Osten 3
D. Domínguez-Ojeda 1 , A.E. Rojas-García 2 , M.L. Robledo-Marenco 2 , B.S. Barrón-Vivanco 2 , J.T. Nieto-Navarro 1 , I.M. Medina-Díaz 2
1 Departmento de Ecología, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico 2 Maestría en Manejo y Conservación de Recursos Naturales, El Colegio de la Frontera Sur, Lerma, Campeche, Mexico 3 Departmento de Ecotoxicología, Instituto EPOMEX, San Francisco de Campeche, Campeche, Mexico
Introduction: In the southern Gulf of Mexico, one of the principal groups of pollutants is the persistent organic compounds, which include organochlorine pesticides. Due to the important ecological role played by elasmobranchs in the marine environment, those present in the area can be taken as sentinel species for biomonitoring purposes. Objective: To analyze the concentrations of organochlorine pesticides in the liver of three species (Rhizoprionodon terraenovae, Sphyrna tiburo and Dasyatis americana) with high commercial importance in Campeche and Yucatan. Materials and methods: Samples portions of livers of the species were collected and analyzed by gas chromatography to determine the concentrations of organochlorine pesticides, grouped in nine chemical families. For the comparison of the concentrations, we used multivariate and univariate techniques considering species, sex and size as factors. Results: Only 31 (53.3%) of the samples showed some organochlorine residues. The main pollutants were HCH, chlordane, dieldrin, endosulfan, endrin and heptachlor. The highest total concentration was found in R. terraenovae, while the highest average concentration was found in S. tiburo. We did not find statistical evidence of significant differences in multivariate average concentrations; however, we were able to detect differences between species in terms of heptachlor concentrations. With the exception of DDT, confidence intervals (at 95%) for each pollutant exceed the maximum tolerance values, as stated by the Mexican NOM-004ZOO-2001 and the FDA in the USA. Conclusions: Ranking the species by the highest values of total concentration, R. terraenovae was first (81.73 ppm), followed by S. tiburo and D. americana. Confidence intervals for concentrations of aldrin, chlordane, dieldrin, endrin and endosulfan exceeded the maximum tolerance limits in Mexico and the United States. This is the first reference on the use of elasmobranchs in biomonitoring of organochlorine compounds in this particular area of the Gulf of Mexico. http://dx.doi.org/10.1016/j.toxlet.2016.07.249
1 Escuela Nacional de Ingeniería Pesquera, Universidad Autónoma de Nayarit, San Blas, Nayarit, Mexico 2 Laboratorio de Contaminación y Toxicología Ambiental, Universidad Autónoma de Nayarit, Tepic, Nayarit, Mexico
Introduction: Tributyltin (TBT) and its derivatives are widely used as antifouling paints, resulting in their release into the marine environment. Aquatic invertebrates, particularly marine gastropods, are extremely sensitive to TBT and undergo changes in the imposition of male secondary sex characteristics in response to exposure. Materials and methods: This study aimed to evaluate the development of imposex and the expression of the retinoid X receptor (RXR) in tissues of Plicopurpura pansa (males and females) exposed to TBTCl (10 g Sn/L). Results: The histological results showed a penis-like structure in imposexed females and an undeveloped vas deferens that lacked circular muscular layers. TBTCl treatment increased the messenger RNA (mRNA) of RXR in females with imposex. The highest level of mRNA of RXR was found in the digestive gland, and penis-forming area in females under in vivo exposure compared with control females. Conclusions: These results indicate that TBTCl modulates mRNA levels of RXR in females. The mRNA level of RXR in imposex females and females exposed to TBTCl was similar to that of males, indicating that RXR might contribute to the development of imposex. To our knowledge, this study is the first to show that TBTCl induces imposex and biphallia in this snail species, and that this effect is accompanied by an increase in RXR expression. Financial support: This research was made possible through NAYARIT 2008-C01-83389 grants. http://dx.doi.org/10.1016/j.toxlet.2016.07.250 PP5.10 Oxidative stress and histopathology responses in Danio rerio exposed to anionic surfactant P.C. González, B.A. Zamora, G.I. Pérez, L.R. Mena, V.J. Pérez, P.M. Amendola, C.R. Rodríguez Department of Marine Resources, Center for Research and Advanced Studies of the National Polytechnic Institute, Merida, Yucatan, Mexico Introduction: Dioctyl sodium sulfosuccinate (DOSS), an anionic surfactant is the main active component of the oil dispersant COREXITTM , widely used in oil spills disasters such as the Deepwater Horizon. The effect of this chemical compound exposure on aquatic organisms and its potential impact on human health is urgently needed. Objective: The aim of this study was to evaluate the effect of DOSS exposure in gene expression and its histological damage on Zebrafish Danio rerio. Materials and methods: A static bioassay of acute exposure to DOSS (10, 50 and 80 mg/L) was performed during four days without water exchange, and samples were collected at 24, 48, 72 and 96 h. Then, for each sampled individual, gene expression by RT-qPCR was
Abstracts / Toxicology Letters 259S (2016) S73–S247
evaluated using a gill portion and multiple organs were used to detect histological damage by Hematoxylin and Eosin staining. Results: Analyses of mRNA levels revealed that changes in gene expression occurred after 48 h of exposure, and it was at 72 h when most of the genes analyzed were up-regulated. The expression of the SOD, IL-8 and XPF increased in all DOSS concentrations levels tested, while GPX and XPA were up-regulated only at 10 and 80 mg/L. Tumor-necrosis factor ␣ did not have any significant change in its expression at none concentration (p > 0.05). Conclusions: The data show unidirectional response between oxidative stress, nucleotide excision repair pathway and immune system genes in the test performed. Financial Support: This study was supported by the Secretariat of Energy-National Council of Science and Technology (SENERCONACyT) Project and CONACyT Mixed Funds (FOMIX-Yucatán). http://dx.doi.org/10.1016/j.toxlet.2016.07.251 PP5.11 Antioxidative, endocrine and detoxification gene expression and epigenetic changes of Mexican shoal flouder (Syacium gunteri) from the Gulf of Mexico M.A. Quintanilla-Mena 1 , A. Quiroz-Moreno 2 , O. Zapata-Perez 1 1
Laboratorio de Ecotoxicología Acuática, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Mérida, Mérida, Yucatán, Mexico 2 Laboratorio de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, Mexico Aquatic systems are continually disturbed by many xenobiotics, which are released by different human activities, producing deleterious effects on species living on these contaminated environments. Many species of fish represent a significant role for toxicological tests in polluted areas. The use of molecular analysis, such as gene expression and epigenetic changes, warn us on time about the damage caused by exposure to pollutants. The objective of this study was to evaluate the expression and variation of six genes that are sensitive to exposure of toxic substances (GST, GPx, GR, CAT, VTG y CYP1A), in the shoal flounder (Syacium gunteri) collected in front of the northwest (Tamaulipas-Veracruz), south (Tabasco-Campeche) and southeast (Yucatan) of the Gulf of Mexico. These genes were quantitatively measured by real time reverse transcription polymerase chain reaction (qRT-PCR). At the same time, we measured the global DNA methylation by a competitive ELISA essay. Results showed that the expressions of genes in S. gunteri, related to oxidative stress (GST, GPx and GR), from southeastern of the Gulf of Mexico, are higher than those of the other two regions. Another oxidative stress gene (CAT) showed an opposite behavior, with the highest expression on northwest and south of the Gulf of Mexico. The VTG expression, a gene related to endocrine disruption, was present in males; this could mean that the population in those places is presenting reproductive impairments. The CYP1A expression, related to biotransformation and detoxification, was erratic in all study area, with its highest expression on the southeast of the gulf. A low level of DNA methylation was present in all the sampled zones (∼4% to ∼2%) compared with previous reports about other fish species (∼7% to ∼9%), suggesting that the genome of the collected organisms are hypomethylated. This study is the first in Mexico evaluating gene expression and changes in epigenetic factors such as DNA methylation from an ecotoxicological point of view using very sensitive and specific molecular techniques. http://dx.doi.org/10.1016/j.toxlet.2016.07.252
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PP5.12 Ecogenotoxic study of the Lagoon of Illusions, Tabasco using devil fish as a bioindicator O.S. López 1 , S.L. Juárez 1 , N.E. García 1 , P.J.A. Rubio 1,2 , H.P. Limón 3 1
Maestría en Ciencias en Sistemas del Ambiente, Centro de investigación en Genética y Ambiente, Catedra CONACyT-CIGyA, Mexico 2 Catedra CONACyT-CIGyA, Mexico 3 Facultad de Odontología, Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico Introduction: Aquatic ecosystems near to urban areas undergo persistent deterioration as a result of human activities. The Laguna de las Ilusiones, located in Tabasco, Mexico, is a natural aquatic system declared as a protected area, and it is considered as a regulator of the microclimate, as well as an area of refuge, nesting and breeding of various species including birds, mammals and reptiles. Further, the Laguna is considered as a tourist and recreational space. Objective: We evaluated whether water from Laguna de las Ilusiones, Villahermosa, Tabasco is a potential source of genotoxicity, using the fish devil as bioindicator. Materials and methods: Two sampling were performed (2013–2014). Weight and height of each organism were determined. Physicochemical parameters in water, including pH, temperature, DO, COD and TDS were determined using a multiparametric instrument. Frequency of micronuclei (MN) in devil fish erythrocytes was assessed as a genotoxicity indicator. Results: The pH of lagoon water samples were 9.6 units and 8.4 units for first and second samplings, respectively. In both samplings, the OD was above the reference limit established for protection of aquatic life. COD were above 121.5 mg/L, indicating contamination in water lagoon. Fish weights ranged from 380 to 2200 g, and heights ranged from 32.5 to 82.0 cm. As for ecotoxicological assessment, in 2013 the median MN frequency in devil fish erythrocytes was 4.0 ± 3.6 MN/2000 cells, ranging from 1.0 MN/2000 cells to 18.5 MN/2000 cells, whereas in 2014, the median MN frequency was 63.0 ± 7.3 MN/2000 cells, ranging from 51.5 MN/2000 cells to 97.5 MN/2000 cells. Finally, morphometric parameters and MN frequency were not correlated. Conclusions: The increase in MN frequency reveals that water lagoon may represent a potential source of genotoxicity. Further, our data suggests the presence of chemicals that targets DNA, representing a latent risk to the biota of the lagoon ecosystem, and even to humans. In addition, our data suggests that fish devil may be used as a biomonitor for assessing genotoxicity of pollutants in water bodies. Financial support: Promotion Program Research. UJATabasco, Project UJAT-2013-1A-05. http://dx.doi.org/10.1016/j.toxlet.2016.07.253