Acute and subchronic effects of ibuprofen on the ten spotted live-bearer fish Cnesterodon decemmaculatus (Jenyns, 1842).

Ibuprofen (IBP) is an anti-inflammatory drug found in aquatic environments, potentially toxic for the biota. We exposed the test fish C. decemmaculatus to two environmentally relevant concentrations (50 and 100 µg IBP/L) for 4 and 12 d and evaluated the effect on some biomarkers. Micronucleus test, nuclear abnormality test and comet assay indicated cyto-genotoxicity at both concentrations and exposure periods. Oxidative stress and biochemical biomarkers were not affected, excepting muscle AChE activity for 4 d. Muscle metabolic biomarkers showed significant decrease in ETS, lipid and protein content, while carbohydrate content was not affected. The CEA index increased at the lower IBP concentration for 4 and 12 d, possibly due to changes in body energy reserves. A full-factorial GLM performed to assess the effects of IBP and exposure times showed that the metabolic and genotoxicity biomarkers were the most sensitive to IBP toxicity, mainly at 50 µg IBP/L for 4 d.

Multibiomarker response in ten spotted live-bearer fish Cnesterodon decemmaculatus (Jenyns, 1842) exposed to Reconquista river water.

The aim of this paper is to assess the water quality to chemical pollution at Roggero Dam, the headwater of the Reconquista river, and to perform a Cadmium (Cd) contamination pulse simulation through a wide battery of biomarkers which included: genotoxicity and enzymatic biomarker parameters on a neotropical teleost fish namely Cnesterodon decemmaculatus. Water samples were taken in order to determine the river's physicochemical profile. An integrative approach was applied using a biomarker index. The bioassay involved the use of laboratory culture adult animals, acclimatized in moderately hard water (MHW) and fed ad libitum. A semi-static 96h bioassay was conducted and the experimental groups were as follows: [1] river water (Rg); [2] river water + 2mg/L Cd (RgCd); [3] MHW + 2mg/L Cadmium (Cd), positive metal control; [4] MHW + 5mg/L Cyclophosphamide (positive genotoxicity control -CP); [5] MWH, negative control (NC). At the end of the exposure time fishes were sectioned and the following biomarkers were determined: 1) condition factor rate (CF); 2) for the anterior section (A) (head): glutathione (GSH) and protein (Pr) content; 3) for the body midsection (M) (viscera): Pr, GSH, Glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD). Blood samples were also taken from the fish specimens to estimate the frequency of micronuclei (MN) as well as other nuclear abnormalities (NA). The physicochemical profile of the river water sample indicated high Copper concentrations. CAT and SOD activity and total Pr content did not show any significant changes. GST activity decreased in fish exposed to Rg, while GSH content decreased significantly for all treatments compared to controls in MHW. These results would seem to point to a reduction in cell defense capability as a result of the depletion antioxidants such as GSH. The NA frequency increased significantly in all treated groups while MN frequency was increased only in Cd and CP groups. Using some the biomarkers measured, a biomarker index was estimated which revealed that fish exposed to Rg were 90% affected or highly affected, while those exposed to RgCd were 80% and Cd 68% affected or highly affected. The obtained results indicate the usefulness of the use of a battery of variables by means of the biomarker index to analyze water quality.

Use of Lithobates catesbeianus tadpoles in a multiple biomarker approach for the assessment of water quality of the Reconquista River (Argentina).

The water quality of the Reconquista River (Argentina) water was monitored between 2009 and 2010 by means of a multiparametric approach. This periurban river is affected by agricultural, urban, and industrial discharges. Water samples were collected at a dam located in the headwaters and at 18 km downstream (M). Physicochemical profile and two water-quality indices (WQIs) were determined. Laboratory bioassays were performed by exposing Lithobates catesbeianus tadpoles to environmental samples for 96 h and determining the following parameters: (1) brain: acetylcholinesterase (AChE) activity; (2) gill: catalase and glutathione-S-transferase (GST) activities and glutathione (GSH) content; (3) liver: CAT and GST activities, superoxide dismutase, lipid peroxidation, and GSH content; (4) condition factor and hepatosomatic index; and (5) genotoxicity [micronucleus (MN) test in erythrocytes]. Physicochemical profile and WQIs corresponded with extensive pollution in M. Important temporal and spatial variability in biomarkers of tadpoles exposed to samples was found. Multivariate analyses showed that AChE in brain, MN frequency, liver and gill GST activities, and GSH content were key biomarkers.

Influencia de la especiación de los metales pesados en medio acuático como determinante de su toxicidad / Influence of the heavy metals speciation in the aquatic environment as determinant of their toxicity

La captación y toxicidad de los metales pesados para los organismos acuáticos están influidos no sólo por su concentración; también son relevantes el tiempo de exposición y los factores bióticos y abióticos del ambiente. Para considerar las relaciones de los metales con la biota acuática se deben tener en cuenta tres niveles de interés: a) la especiación en el ambiente, b) las interacciones con la membrana plasmática en la interfase organismo-ambiente, así como otros factores secundarios que pueden afectar los mecanismos funcionales básicos del individuo y c) la partición del elemento en los compartimentos del organismo y los efectos biológicos resultantes de su interacción con los receptores en los sitios de acción. En esta revisión se presentan ejemplos que ilustran la necesidad de determinar no sólo la concentración total de un metal en solución acuosa sino también el perfil de su entorno fisicoquímico y su biodisponibilidad; esta última puede ser correlacionada directamente con la especiación química a través del modelo de actividad del ion libre (en inglés, FIAM, free ion activity model). Se discute además la posibilidad de usar organismos como sensores de la biodisponibilidad de los metales en relación con su especiación química. Dentro de ellos, las algas representan un grupo muy importante ya que muestran una sensibilidad a los contaminantes mucho mayor que otros organismos acuáticos. Se presentan resultados propios obtenidos mediante bioensayos de laboratorio, usando cultivos algales monoespecíficos de Selenastrum capricornutum Printz (= Raphidocelis subcapitata); se ha estudiado el efecto del Cd sobre la inhibición de la fotosíntesis en presencia del quelante EDTA-Na2. Los resultados muestran que la concentración total del Cd no es un buen predictor de su toxicidad para las algas y que su especiación puede afectar la disponibilidad del mismo para los organismos en medio acuático y, consecuentemente, determinar la magnitud de su toxicidad (AU)

Monitoring of organochlorine and organophosphorus pesticides in the water of the Reconquista River (Buenos Aires, Argentina).

The Reconquista river is a typical example of the adverse impact of human activity on a watercourse. Approximately 10% of the population of the country is settled on its basin and it receives wastewater discharges from residences and industries. This paper describes the results of the first systematic data for measurement of pesticides in surface water of the river, based on a monthly monitoring program over two-year span. The analyses were performed, in three sampling stations (S1, S2 and S3), along 46 km of its course, following the AOAC methods. Screening included the following pesticides: (a) Organochlorines: alpha, beta and gamma HCH; heptachlor, heptachlor epoxide; aldrin; endrin; dieldrin; op' and pp' DDT; op' and pp' DDE; alpha and gamma chlordane and endosulphan II; (b) Organophosphates: ethyl and methyl parathion; chlorpyrifos and fenitrothion. From the 60 samples analyzed, 35% contained organochlorine pesticides in a concentration higher than the detection limit. Organophosphates were found in no case. Throughout the studied period, DDT and its metabolite DDE were only found in S1 and gamma chlordane in S3; heptachlor was present in 50% of the samples of S2 and in 35% of S3, while HCH isomers were detected in 38% of S2 and 45% of S3 samples. Neither temporal nor spatial trends were found. There was not a relationship between the time of samplings and the fumigation season for farming purposes. At all locations, pesticides levels were found to be between 40 and 400 times higher than the legal limits established for protection of aquatic life.

Arginase activity of Bufo arenarum embryos is sensitive to external osmotic pressure.

We investigated the impact of environmental osmotic stress on the arginase activity if Bufo arenarum embryos. The activity at the first developmental stages was not sensitive to extreme variations of osmotic pressure of the environment. Later, at gill circulation, opercular fold and right operculum stages, the enzyme activity of embryos developed in concentrated solutions decreased significantly with respect to control. At complete operculum stage, the arginase activity increased 1.3-2.5 fold in all conditions, and was significantly higher in embryos grown in distilled water than in control animals.

Arginase activity of Bufo arenarum embryos is sensitive to external osmotic pressure

We investigated the impact of environmental osmotic stress on the arginase activity if Bufo arenarum embryos. The activity at the first developmental stages was not sensitive to extreme variations of osmotic pressure of the environment. Later, at gill circulation, opercular fold and right operculum stages, the enzyme activity of embryos developed in concentrated solutions decreased significantly with respect to control. At complete operculum stage, the arginase activity increased 1.3-2.5 fold in all conditions, and was significantly higher in embryos grown in distilled water than in control animals

Arginase activity in Bufo arenarum embryos.

The evolution of arginase activity during development of Bufo arenarum embryos was studied. The enzyme activity was detected after the neural groove stage, being low at the following early stages and increasing progressively until the end of the embryonic development. Arginase activity was first found in the neurula stage, when an outline of basic structures for renal and hepatic function is present. The activity increased two- or three-fold at the beginning of the larval stages.

Arginase activity in Bufo arenarum embryos

The evolution of arginase activity during development of Bufo arenarum embryos was studied. The enzyme activity was detected after the neural groove stage, being low at the following early stages and increasing progressively until the end of the embryonic development. Arginase activity was first found in the neurula stage, when an outline of basic structures for renal and hepatic function is present. The activity increased two- or three-fold at the beginning of the larval stages

Liver arginase activity and urinary nitrogen products profile in adult Bufo arenarum under different protein intake.

The effect of different levels of diet protein on adult Bufo arenarum liver arginase activity and protein content, plasma urea and urinary profile of nitrogen waste products was estimated. Animals kept under environmental constant conditions were submitted to a nutritional standardization period being fed beef meat daily during four days. Then animals were distributed in three groups: Group 0 (control), that was sampled at the end of the standardization period; Group 1, that was starved for 18 days and Group 2, that was fed daily for 18 days and then sampled. With respect to controls, liver arginase specific activity was significantly lower in starving toads (Group 1); liver protein content was elevated in fasted animals (Group 1) and plasma urea concentration increased in the intensive feeding group (Group 2). Urinary nitrogen end products in animals from both control and experimental groups showed no changes either in their absolute values or in their partition percentage rates.

Ontogenic screening of aldosterone in the South American toad Bufo arenarum (Hensel).

The content of aldosterone in the South American toad Bufo arenarum embryos developed in Holtfreter's 10% solutions and in distilled water was measured. The screening was carried out on embryos from the following periods of their development: 15 min after fertilization; gray crescent-32 cells; mid cleavage-late gastrula; neural plate-neural tube; tail bud-heart beat; gill circulation-tail fin circulation and operculum fold-complete operculum. The aldosterone content of embryos incubated both in Holtfreter and in distilled water decreased gradually up to gill circulation-tail fin circulation stages. The steroid content of both groups of embryos rose sharply at the end of their development (operculum fold-complete operculum); the observed increase was significantly higher in distilled water animals.