Exposure to aluminum, aluminum + manganese and acid pH triggers different antioxidant responses in gills and liver of Astyanax altiparanae (Teleostei: Characiformes: Characidae) males.

Exposure to aluminum (Al) and aluminum + manganese (Mn) can trigger an increase in reactive oxygen species (ROS) and modify the activity of oxidative defense enzymes. This study investigated whether exposure to Al and Al + Mn at acid pH for 24 and 96 h causes oxidative stress evidenced by antioxidants and oxidative damage in the gills and liver of sexually mature Astyanax altiparanae males. The fish were subsequently immersed in metal-free water for 24 and 96 h to see whether they recovered from the effects of these metals. Exposure to an acid pH boosted the activity of gill superoxide dismutase (SOD) at 96 h and the fish did not recover when immersed for the same period in water at neutral pH. Exposure to Al increased glutathione (GSH) levels (24 h) in the gills, returning to control levels during the recovery period, showing the efficiency of the antioxidant system in preventing lipid peroxidation of the gills and liver. Mn did not modify the activity of the enzymes studied, but did trigger late hepatic lipid peroxidation during the recovery period. The group exposed to Al + Mn exhibited several alterations, including increased concentration of GSH, as well as higher GPx and GR activity in the gills. Despite the defensive responses triggered by acute exposure, during the recovery period there were alterations in catalase (96 h) and an increase in hepatic metallothionein (24 h), but this did not prevent hepatic lipid peroxidation. Al and Al + Mn produced different effects, and the timing of enzymatic and non-enzymatic antioxidant defenses also differed.

Physiological response of invasive mussel Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae) submitted to transport and experimental conditions / Resposta fisiológica do mexilhão invasor Limnoperna fortunei (Dunker, 1857) (Bilvalvia: Mytilidae) submetido ao transporte e condições experimentais

Abstract Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally, the tolerance of L. fortunei specimens to the stressor tested herein can help us understand the invasive capacity of this mussel during the establishment process.

Resumo A criação bem sucedida de animais em condições de laboratório para processos comerciais ou experimentais é uma cadeia complexa que inclui vários fatores de estresse (ex. coleta e transporte) que tem como consequência a redução das condições naturais do animal, prejuízos econômicos e resultados biológicos inconsistentes. Desde a invasão do bivalve Limnoperna fortunei (Dunker, 1857) na América do Sul, vários estudos têm sido realizados para ajudar no controle e gestão dessa praga em plantas industriais que utilizam água. Relativamente pouca atenção tem sido dada ao processo de criação de L. fortunei em laboratório, sua condição quando exposta ao estresse e sua aclimatação a condições de laboratório. Considerando estes aspectos, os objetivos deste estudo foram: (i) investigar as respostas fisiológicas de L. fortunei submetidos ao processo de depuração e subsequente transporte (sem água/condição seca) em duas temperaturas, analisando as diferentes concentrações de glicogênio e (ii) monitorar as concentrações de glicogênio nos diferentes grupos, quando mantidos por 28 dias em condições de laboratório. Com base nos resultados obtidos, a depuração não afetou nenhum grupo quando eles foram submetidos a oito horas de transporte. A variação da concentração de glicogênio entre os espécimes do campo quando depurados e não depurados, foi significativa apenas em relação à primeira semana em laboratório para o grupo não depurado e à segunda semana para o grupo depurado. Além disto, a temperatura testada não afetou os grupos submetidos ao transporte. As concentrações de glicogénio foram semelhantes as dos espécimes do campo a partir da terceira semana, o que sugere que os espécimes estão aclimatados às condições de laboratoriais neste período de tempo. Assim, os resultados indicam que o transporte ao ar e o tempo de aclimatação podem ser incorporados com sucesso aos estudos experimentais com L. fortunei. Finalmente, o conhecimento sobre a tolerância de L. fortunei ao estresse pode ajudar a entender a capacidade invasiva deste durante o processo de estabelecimento.

Physiological response of invasive mussel Limnoperna fortunei (Dunker, 1857) (Bivalvia: Mytilidae) submitted to transport and experimental conditions.

Successful animal rearing under laboratory conditions for commercial processes or laboratory experiments is a complex chain that includes several stressors (e.g., sampling and transport) and incurs, as a consequence, the reduction of natural animal conditions, economic losses and inconsistent and unreliable biological results. Since the invasion of the bivalve Limnoperna fortunei (Dunker, 1857) in South America, several studies have been performed to help control and manage this fouling pest in industrial plants that use raw water. Relatively little attention has been given to the laboratory rearing procedure of L. fortunei, its condition when exposed to a stressor or its acclimation into laboratory conditions. Considering this issue, the aims of this study are to (i) investigate L. fortunei physiological responses when submitted to the depuration process and subsequent air transport (without water/dry condition) at two temperatures, based on glycogen concentrations, and (ii) monitor the glycogen concentrations in different groups when maintained for 28 days under laboratory conditions. Based on the obtained results, depuration did not affect either of the groups when they were submitted to approximately eight hours of transport. The variation in glycogen concentration among the specimens that were obtained from the field under depurated and non-depurated conditions was significant only in the first week of laboratory growth for the non-depurated group and in the second week for the depurated group. In addition, the tested temperature did not affect either of the groups that were submitted to transport. The glycogen concentrations were similar to those of the specimens that were obtained from the field in third week, which suggests that the specimens acclimated to laboratory conditions during this period of time. Thus, the results indicate that the air transport and acclimation time can be successfully incorporated into experimental studies of L. fortunei. Finally, the tolerance of L. fortunei specimens to the stressor tested herein can help us understand the invasive capacity of this mussel during the establishment process.

In vivo and in vitro exposures for the evaluation of the genotoxic effects of lead on the Neotropical freshwater fish Prochilodus lineatus.

In the present study, in vivo and in vitro exposures were used to assess the genotoxicity of lead (Pb) to the freshwater fish Prochilodus lineatus. The comet assay using blood, liver and gill cells, and the occurrence of micronuclei (MN) and other erythrocytic nuclear abnormalities (ENA) were used to assess the genotoxic potential of lead in vivo. Metallothionein content (MT) was measured in fish liver in order to evaluate the protection of fish against Pb toxicity. Fish erythrocytes were exposed to Pb in vitro (1, 3 and 6 h) and the number of viable cells, DNA integrity, using the comet assay, and lysosomal membrane stability, measured by the neutral red retention assay (NRRA) were analyzed. The results of the comet assay after in vivo toxicity tests (6, 24 and 96 h) showed that Pb was genotoxic for all the three tissues analyzed after 96 h exposure. A significant increase in liver MT content was observed after 6 and 24 h of Pb exposure. MN frequency did not increase after Pb exposures, but the frequency of the other ENA, such as kidney-shaped nuclei, segmented nuclei and lobed nuclei, showed a significant increase after 24 and 96 h, indicating that ENA is a better biomarker for Pb exposure than MN alone after short-term exposures. The results of the comet assay performed with erythrocytes in vitro exposed to lead confirmed its genotoxic effect and showed that DNA damage increased with increasing exposure time. Moreover, the NRRA clearly indicated that Pb induces a destabilization of the lysosomal membrane. These results demonstrate the potential genotoxicity and cytotoxicity of lead after acute exposures.

Genetic damage in the bivalve mollusk Corbicula fluminea induced by the water-soluble fraction of gasoline.

Although gasoline is an important contaminant of aquatic ecosystems, information concerning the potential effects of this petroleum derivative on the DNA of aquatic biota is lacking. The present study aimed to evaluate the genotoxic and mutagenic effects of acute exposures (6, 24, and 96h) to gasoline water-soluble fraction (GWSF), diluted to 5%, on the Asian clam Corbicula fluminea. The comet assay and the micronucleus (MN) test were performed on hemocytes and gill cells of C. fluminea. For the three different times tested, the comet assay indicated DNA damage in hemocytes and gill cells of C. fluminea exposed to GWSF. The MN test detected significant damage in the genetic material of the hemocytes only after 96h of exposure to GWSF. The recovery capacity of organisms previously exposed for 6h to GWSF was also evaluated with the comet assay. The results revealed a great capacity of this species to repair DNA damage; following 6h of recovery, the comet score returned to that of the control groups. Overall, our findings indicate that GWSF has genotoxic and mutagenic effects on C. fluminea. In addition, the present results confirm the sensitivity of C. fluminea to damage caused by exposure to environmental contaminants, and, therefore, its suitability for use in environmental monitoring studies.

Genotoxic effects of Roundup on the fish Prochilodus lineatus.

Glyphosate-based herbicides, such as Roundup, represent the most extensively used herbicides worldwide, including Brazil. Despite its extensive use, the genotoxic effects of this herbicide are not completely understood and studies with Roundup show conflicting results with regard to the effects of this product on the genetic material. Thus, the aim of this study was to evaluate the genotoxic effects of acute exposures (6, 24 and 96 h) to 10 mg L(-1) of Roundup on the neotropical fish Prochilodus lineatus. Accordingly, fish erythrocytes were used in the comet assay, micronucleus test and for the analysis of the occurrence of nuclear abnormalities and the comet assay was adjusted for branchial cells. The results showed that Roundup produces genotoxic damage in erythrocytes and gill cells of P. lineatus. The comet scores obtained for P. lineatus erythrocytes after 6 and 96 h of exposure to Roundup were significantly higher than respective negative controls. For branchial cells comet scores were significantly higher than negative controls after 6 and 24 h exposures. The frequencies of micronucleus and other erythrocyte nuclear abnormalities (ENAs) were not significantly different between Roundup exposed fish and their respective negative controls, for all exposure periods. In conclusion, the results of this work showed that Roundup produced genotoxic effects on the fish species P. lineatus. The comet assay with gill cells showed to be an important complementary tool for detecting genotoxicity, given that it revealed DNA damage in periods of exposure that erythrocytes did not. ENAs frequency was not a good indicator of genotoxicity, but further studies are needed to better understand the origin of these abnormalities.

Swimming performance of the freshwater neotropical fish: Pimelodus maculatus Lacepède, 1803.

The present study used fixed and increasing velocity tests in an experimental apparatus based on Brett's respirometer to examine prolonged and sustained speeds of the "mandi-amarelo", Pimelodus maculatus. When comparing the curves of critical speed versus total length between the mandi and the sockeye salmon Oncorhynchus nerka, it is observed that for an equal total length, the mandi presents a greater speed, probably due to water temperature differences. The sustained speed for the species was estimated in 5 lengths per second and the percentage of fatigued fish within time in a certain velocity was established. The data raised for the mandi represents an important contribution to the improvement of the handling of the species, providing guidance and criteria for designing several structures, such as fishways, fish screens and guidance systems.

Swimming performance of the freshwater neotropical fish: Pimelodus maculatus Lacepède, 1803 / Capacidade natatória da espécie neotropical de água doce: Pimelodus maculatus Lacepède, 1803

The present study used fixed and increasing velocity tests in an experimental apparatus based on Brett's respirometer to examine prolonged and sustained speeds of the "mandi-amarelo", Pimelodus maculatus. When comparing the curves of critical speed versus total length between the mandi and the sockeye salmon Oncorhynchus nerka, it is observed that for an equal total length, the mandi presents a greater speed, probably due to water temperature differences. The sustained speed for the species was estimated in 5 lengths per second and the percentage of fatigued fish within time in a certain velocity was established. The data raised for the mandi represents an important contribution to the improvement of the handling of the species, providing guidance and criteria for designing several structures, such as fishways, fish screens and guidance systems.

No presente estudo, foram utilizados testes de velocidade fixa e progressiva em um aparato experimental baseado no respirômetro de Brett, para examinar as velocidades prolongada e sustentável do mandi-amarelo, Pimelodus maculatus. Quando comparadas as curvas de velocidade crítica versus o comprimento do corpo entre o mandi e o salmão Oncorhynchus nerka, é observado que, para um mesmo comprimento, o mandi apresenta velocidades superiores, provavelmente devido a diferenças na temperatura da água. Foram estimadas a velocidade sustentável da espécie em cinco comprimentos por segundo e a porcentagem de peixes fatigados ao longo do tempo em uma dada velocidade estimada. Os dados obtidos para o mandi representam uma importante contribuição para o manejo da espécie, provendo critérios de projeto para a construção de estruturas como mecanismos de transposição e sistemas de proteção e orientação.

Genotoxic and mutagenic effects of diesel oil water soluble fraction on a neotropical fish species.

Numerous spills and leakages involving petroleum and its derivatives have recently occurred in Brazilian rivers. Considering the lack of information regarding the genotoxic response of neotropical fish to these events and the predominance of information regarding saltwater fish, which offers no genuine comparisons, the present work aimed to evaluate the genotoxicity and mutagenicity of the diesel water soluble fraction (DWSF) on the neotropical fish Prochilodus lineatus under acute (6, 24 and 96h) and subchronic (15 days) exposures, using the comet (SCGE) and micronucleus assays. The results indicated genotoxic and mutagenic damage in erythrocytes of P. lineatus exposed to DWSF. Comet scores for fish exposed to DWSF in all experimental periods were significantly higher than the respective negative control groups (fish exposed to clean water for the same period). The relative frequencies of micronucleated erythrocytes for P. lineatus exposed to DWSF under acute and subchronic treatment were also significantly higher than their respective negative controls. Taken together these results showed that acute and subchronic exposures to DWSF produce mutagenic and genotoxic effects on the blood cells of P. lineatus and that the combination of comet and micronucleus assays proved to be both suitable and useful in the evaluation of the genotoxicity of diesel oil due to their complementary action.

Acute morphological and physiological effects of lead in the neotropical fish Prochilodus lineatus

O presente estudo investigou os efeitos do chumbo na morfologia branquial, nos hematócritos e nas concentrações plasmáticas de sódio, glicose, lipídeos, proteínas e colesterol de Prochilodus lineatus exposto a duas concentrações subletais de chumbo durante 96 h. Inicialmente, testes agudos (96 h) e estáticos determinaram a CL50 (96 h) de chumbo para P. lineatus em 95 mg Pb.L-1. As concentrações de chumbo utilizadas nos testes subletais foram 24 e 71 mg Pb.L-1, que correspondem a 25% e 75%, respectivamente, da CL50 (96 h). As brânquias de P. lineatus expostos a ambas as concentrações de chumbo apresentaram maior incidência de lesões histopatológicas, como elevação epitelial, hiperplasia e aneurisma lamelar. P. lineatus não apresentou alterações significativas no hematócrito durante a exposição a ambas as concentrações de chumbo. Peixes expostos a 71 mg Pb.L-1 apresentaram decréscimo significativo do Na+ plasmático após 48 h, o que pode estar se refletindo na redução das taxas de influxo desse íon. P. lineatus expostos a ambas as concentrações de chumbo apresentaram resposta clássica ao estresse, como verificado pela hiperglicemia associada ao decréscimo dos lipídeos e proteínas plasmáticas. A magnitude da resposta ao estresse foi dose-dependente. A resposta apresentada na concentração mais baixa representa um processo adaptativo, enquanto na maior concentração caracteriza a exaustão.

Acute morphological and physiological effects of lead in the neotropical fish Prochilodus lineatus.

The present study investigated lead effects on gill morphology, hematocrit, blood sodium, glucose, lipids, protein, and cholesterol of Prochilodus lineatus exposed to two sublethal lead concentrations for 96 h. Preliminary series of short-term static toxicity tests were run to determine LC50 (96 h) of lead in P. lineatus, which was 95 mg Pb.L-1. Therefore, lead concentrations tested in the sublethal experiments were 24 and 71 mg Pb.L-1, which correspond to 25% and 75% of the LC50 (96 h), respectively. Gills of P. lineatus exposed to both lead concentrations during 96 h presented a higher occurrence of histopathological lesions such as epithelial lifting, hyperplasia, and lamellar aneurism. P. lineatus did not show significant alterations in hematocrit during exposure to both lead concentrations. Fish exposed to the highest lead concentration showed a significant decrease in Na+ plasma concentration after 48 h, possibly reflecting a sodium influx rate decrease. P. lineatus exposed to both lead concentrations presented a "classical general adaptation syndrome to stress", as hyperglycemia associated with lowered lipids and proteins was reported. Stress-response magnitude was dose-dependent. While the response to the lowest lead concentration might represent adaptation, the highest concentration seems to characterize exhaustion.

A morphological study on posterior gills of the mangrove crab Ucides cordatus.

Morphological and histological studies on posterior gills of the mangrove crab Ucides cordatus showed that the 5th gill (of 7) has a larger surface area and a greater number of lamellae compared to the 6th gill. Regular separation of gill lamellae, important when the gill is in air, is maintained by enlargements of the marginal canals. Conical, spine-like structures along the efferent vessel of both 5th and 6th gills were also observed. In addition, pillar cells, a discontinuous lamellar septum and a hypobranchial artery were observed. The presence of valve-like structures near the efferent vessel was also indicated. These structures, together with the pillar cells, may have a role in directing the hemolymph flow towards certain gills during particular physiological states. Localization of osmoregulatory epithelia in the lamellae of both gills was inferred from dimethylaminostyrylethylpyridiniumiodine staining. Apparently gills 5 and 6 have osmoregulatory epithelial cell patches of similar area, corresponding to 43% and 38% of the total lamellae area, respectively. However, their localization is quite different. Gill number 5 osmoregulatory patches seem to be restricted to the afferent region of the lamella whereas in gill number 6, they are more dispersed over the entire lamella. These differences may be related to the particular functional characteristics of these gills.

Diabetes in St. Regis Mohawk Indians.

OBJECTIVE: To establish a registry of diabetes patients and to determine the point prevalence of diabetes in the St. Regis Mohawk New York community at the end of August 1989. RESEARCH DESIGN AND METHODS: Participants in this study consisted of residents of the St. Regis Mohawk reservation in New York state, who were registered for health care at the St. Regis Mohawk Clinic. This study was a survey of diabetes cases using the National Diabetes Data Group criteria for diagnosis with comparison with the U.S. rates determined from the 1987-1982 National Health Interview Survey and Canadian Mohawk Indian rates from other studies. RESULTS: The age-adjusted prevalence of 48.8/1000 Mohawk population was two times (95% CI 1.2-3.2) the U.S. rate. Although precise comparisons with Canadian studies are difficult because of differences in study design, rates for Quebec Mohawks aged 45-64 yr were similar. CONCLUSIONS: A high prevalence (21%) among New York Mohawk Indians < 45 yr of age, compared with 17% of diabetic patients in that age-group in the U.S. population, means that complications resulting from diabetes will occur at a relatively young age, placing an increased burden on the health-care system with costs of patient care associated with diabetes increasing accordingly. The registry system is being used to gather information on the prevalence and incidence of diabetic complications and risk factors for developing diabetes. These data will be used to evaluate programs.

Effect of benzene on the swimming activity of Mysidopsis juniae (Crustacea, Mysidacea)

The effects of benzene on the swimming activity of the crustacean Mysidopsis juniae were investigated. The swimming activity of M. juniae was observed after 1.3 and 6 h of exposure to 5, 10 15 and 20 ppm benzene in sea water (35 ñ 1 grade/00 S, 25 ñ 1 grade C). The mysids were observed with a pair of coupled to a camara lucida, and the swimming activity was measured in a Petri dish, corresponding to the distance (cm) covered by the animals in 1 min (N=150 animals). The swimming activity of mysids exposed to 20 ppm benzene decreased significantly after all three periods of exposure to values which were 80-90% smaller than the control value. On the other hand, after 6 h exposure to 5 ppm benzene, the swimming activity of the mysids was significantly higher, increasing by 87% in relation to the control (29.8 ñ 8.9 cm?min). Furthermore, a slight nonsignificant increase in swimming activity was also observed in mysids submitted to 5, 10, 15 and even 20 ppm benzene, as the period of exposure to the pollutant increased from 1 to 6 h. These results indicate that short-term exposure to sublethal benzene concentrations can affect the swimming activity of mysids. in these situations, mysid populations can be seriously damaged since alterations in swimming activity could lead to a reduction in food intake and to a marked increase in their susceptibility to predation by other organisms