Muscle Acetylcholinesterase Activity Research Articles

Both acute glyphosate and the aminomethylphosphonic acid intoxication decreased the acetylcholinesterase activity in rat hippocampus, prefrontal cortex and gastrocnemius muscle

It has been reported that glyphosate, one of the most common herbicides used in agriculture, impairs locomotion and cognition. Glyphosate has a variable half-life in soil up to biotic and/or abiotic factors transform the molecule in metabolites such as the aminomethylphosphonic acid (AMPA) that has a longer half-life. In this study, female Sprague Dawley rats were acutely exposed to different doses of glyphosate or AMPA (i.e. 10, 56 or 100 mg/kg) and, subsequently, the acetylcholinesterase (AChE) activity was measured in the hippocampus, prefrontal cortex (PFC) and the gastrocnemius muscle. Both glyphosate and AMPA produced a similar decrease in the AChE activity in all the tissues tested. These results suggest that interference with normal cholinergic neurotransmission may be one of the mechanisms involved in glyphosate-induced motor alterations in rats. Moreover, our results highlight the biological importance of AMPA as a molecule with anticholinesterase action in brain and skeletal muscle. To our knowledge, this is the first report showing in vivo that AMPA, the major metabolite of glyphosate, behaves as an organophosphate.

Fungicides from rice cultivation (tebuconazole and azoxystrobin) alters biochemical and histological markers of hammertoad tadpoles (Boanafaber).

Tebuconazole (TBZ) and azoxystrobin (AZX) are fungicides frequently used in rice cultivation. Despite protecting crops against fungal diseases, these compounds can contaminate the natural environments close to the crops, exerting negative effects on non-target organisms, the present study aimed to characterize the contamination by fungicides of a river that flows in an area dominated by rice cultivation in the north of the state of Santa Catarina, SC, Brazil. Concentrations of TBZ and AZX found in the field were used to evaluate their negative effects on development, biochemical biomarkers and histopatology of the liver of a native tadpole species, the hammerfrog (Boana faber). Tadpoles were exposed for 16 days to the lowest (1.20 μg/L) and highest (2.60 μg/L) concentration of TBZ, lowest (0.70 μg/L) and highest (1.60 μg/L) concentration of AZX, and the mix of both fungicides at lowest and highest concentration of each found in field analyses. Exposure to the lower TBZ concentration and both concentrations of the Mix accelerated the development of tadpoles. AZX caused an increase in the activities of glutathione S-transferase (GST), carboxylesterase (CbE) and glucose-6-phosphate dehydrogenase (G6PDH) in the liver, an increase in the levels of protein carbonyls (PC) in the liver and an increase in the activity of acetylcholinesterase (AChE) in muscle of tadpoles. TBZ, on the other hand, generated an increase in GST, G6PDH, PC and histopathological severity scores in liver and in muscle AChE activity. The effects were more intense in the groups exposed to the Mix of contaminants. No treatment altered brain AChE. The data showed that the fungicides from in rice cultivation found in natural aquatic environments around the crops pose risks to the health of the animals, compromising their metabolism and development.

BDE-99 (2,2′,4,4′,5 - pentain polybrominated diphenyl ether) induces toxic effects in Oreochromis niloticus after sub-chronic and oral exposure

PBDEs are toxic, lipophilic, hydrophobic, and persistent artificial chemicals, characterized by high physical and chemical stability. Although PBDEs are known to disturb hormone signaling, many effects of 2,2′,4,4′,5 - pentain polybrominated diphenyl ethers (BDE-99) in fish remain unclear. The current study investigates the effects of BDE-99 in Oreochromis niloticus where sixty-four juvenile fish were orally exposed to 0.294, 2.94, 29.4 ng g−1 of BDE-99, every 10 days, during 80 days. The results showed histopathological findings in liver and kidney, increasing acetylcholinesterase activity in muscle, disturbs in the antioxidant system in liver and brain and decreasing the plasmatic levels of vitellogenin in females. According to multivariate analysis (IBR), the higher doses are related to the interaction of oxidative and non-oxidative enzymes. The present study provided evidence of deleterious effects after sub-chronic exposure of BDE 99 to O. niloticus, increasing the knowledge about its risk of exposure in fish.

Cholinesterase activity as a potential biomarker for neurotoxicity induced by pesticides in vivo exposed Oreochromis niloticus (Nile tilapia): assessment tool for organophosphates and synthetic pyrethroids

ABSTRACT Organophosphates (OPs) and synthetic pyrethroids (SPs) are the most popular broad spectrum pesticides, used in agriculture as they have a strong pesticidal activity while also being biodegradable in the environment. The present study aimed to demonstrate the effects of these pesticides on the Acetylcholinesterase (AChE) activity in brain, gills and body muscles of Oreochromis niloticus – an important enzyme for the assessment and biomonitoring pollution caused by neurotoxins in the environment. The fish were exposed for 24 and 48 h to the LC0 concentrations of the malathion (1.425 mg/L), the chlorpyrifos (0.125 mg/L) and the λ-cyhalothrin (0.0039 mg/L), respectively. The activity of the AChE was significantly increased (p < 0.05) at 24 h and decreased at 48 h (except for the chlorpyrifos-treated brain and gills while tissues had shown no activity at 48 h’s exposure) in all pesticides-treated tissues. The maximum increase in the activity and inhibition in the AChE activity were recorded as +92% and −52% in the chlorpyrifos and the lambda-cyhalothrin exposed brain tissues, respectively. Thus, the alterations in the AChE activities indicated that the applied pesticides are highly neurotoxic to fish and the enzyme (AChE) could be used as a useful biomarker for estimation of water pollution.

Exposure to pollutants present in Iguaçu River Southern Brazil affect the health of Oreochromis niloticus (Linnaeus, 1758): Assessment histological, genotoxic and biochemical

Urban sewage is a source of major contamination in aquatic systems and contributes to environmental and human health disturbances. This study investigates the effects of sewage-polluted waters from Iguaçu River on the health of juvenile Oreochromis niloticus. Two hundred four specimens were exposed to riverine water in four groups: no diluted, 25 and 50 % diluted water and a control group without tested water for 72 days. Biological samples were obtained for histopathological, neurotoxicity, antioxidant defenses, genotoxicity, metallothionines expression and polycyclic aromatic hydrocarbons (PAHs) metabolites. The results showed histopathological alterations in liver and gills, genotoxic alteration in erythrocytes, reduction of acetylcholinesterase activity in brain and muscle, activation of antioxidant defenses in the liver, recruitment of metals by metallothionein and the detection of PAHs metabolites in bile. These results demonstrate that juveniles of O. niloticus are susceptible to Iguaçu River exposure water and they can be used as indicator of water quality.

Toxicity of silver nanoparticles on different tissues in adult Danio rerio.

Although silver nanoparticles (AgNP) are among the most studied nanomaterials by virtue of their broad application in many areas, little is known about their overall toxicity to aquatic organisms after their contamination of the water environment. This study aimed to analyze the effect of the exposure (96 h) to different AgNP concentrations on Danio rerio (zebrafish) tissues. AgNP were synthesized and characterized by transmission electron microscopy (TEM), showing spherical AgNP of 30.00 ± 16.80 nm size. The effects of different AgNP concentrations (1, 3, and 5 μg L-1) on brain, muscle, gill, and liver tissues of zebrafish were investigated. The results show a significant decrease in brain and muscle acetylcholinesterase (AChE) activity. Liver and gill catalase (CAT) activity also decreased significantly. At the highest exposure concentration, muscle AChE was more inhibited (37.3%) than brain AChE (26.4%) and gill CAT was more inhibited (67.4%) than liver CAT (51.2%). D. rerio also showed gill morphological changes such as fusion of secondary lamellae, curvature, dilated marginal channel, and epithelial lifting. This study indicates that gill CAT together with morphological studies are potential biomarkers for AgNP.

Physiological and biochemical responses of Nile tilapia (Oreochromis niloticus) to acute trichlorfon exposure

Abstract: Trichlorfon [TCF] is an organophosphate compound used to eliminate or control a variety of parasites in farmed fish. The physiological and biochemical responses of juvenile Nile tilapia were studied after 96 hours of exposure to TCF. The experiment was conducted randomly with two treatments: control and TCF (0.5 mg L-1). No mortality or changes in hematological profile were recorded for the fish. On the other hand, we found that TCF exposure caused behavioral, metabolic and hormonal changes that modified the response patterns of the immune and enzymatic defense system in muscle and liver tissues. Increased plasma cortisol and glucose combined with the reduction of acetylcholinesterase activity in muscle and liver tissue after 96-h of TCF exposure indicates chemical stress. In response to this harmful situation, we observed changes in the immune system that lead to an increased number of leukocytes, thrombocytes, monocytes, lysozyme and leukocyte respiratory burst activity. Furthermore, we associate the increased activity of glutathione-S-transferase in liver tissue as a strategy fish use to combat the effects of TCF. Thus, we conclude that TCF affects the physiologic parameters of Nile tilapia, which can generate irreversible situations of recovery of the clinical condition. Such fact highlights the need to search for new compounds that could replace TCF, that have no or few adverse effects on fish species.

Mugil liza (Valenciennes, 1836) biomarker responses in a hypersaline lagoon in southeastern Brazil before and after a microalgal bloom

Araruama lagoon is one of the largest permanent hypersaline lagoons in the world and has been impacted for twenty years by sewage dumping. In early 2005, a Prasinophyceae (Pseudoscourfieldia sp.) phytoplankton bloom occurred, leading to fish mortality during subsequent summers (2006 and 2007). In this context, the aim of the present study was to accompany this historical period through the use of biochemical biomarkers in mullet (Mugil liza) during and after the algal bloom. Mullet were collected from Araruama Lagoon in June and July 2005 and August 2007, as well as from a reference lagoon with no algal blooms, Saquarema Lagoon. Several enzymatic activities in liver were analyzed, namely glutathione peroxidase (GPX), catalase (CAT), total glutathione S-transferase (GSTt), specific GSTπ (pi) and GSTμ (mi) classes and ethoxyresorufin-O-deethylase (EROD), as well as muscle acetylcholinesterase activity (AChE). In 2005, only EROD activity was significantly increased at Araruama Lagoon, indicating induction of the biotransformation enzyme system (CYP 1A1). GSTπ, on the other hand, was lower in the Araruama Lagoon, especially in 2005, when compared to mullet from Saquarema lagoon (reference area). These results highlight the importance of developing actions that go beyond the physical-chemical monitoring of these environments, since the study of ecological relationships and the physiology of organisms affected by algal blooms also include biochemical parameters to evaluate new approaches to icthyotoxicity.

Diclofenac and caffeine inhibit hepatic antioxidant enzymes in the freshwater fish Astyanax altiparanae (Teleostei: Characiformes)

Although concentrations of pharmaceutical compounds in aquatic ecosystems are low, they can cause toxic effects on organisms. The aim of this study was to evaluate the effects of diclofenac (DCF), a non-steroidal anti-inflammatory drug, and caffeine (CAF), a central nervous system stimulant, both alone or combined, in Astyanax altiparanae males under acute exposure (96 h), measuring neurotoxicity biomarkers, antioxidant response and damage at biochemical and cellular levels. DCF concentration in water, separated and combined, was 3.08 mg L−1 and that of CAF was 9.59 mg L−1. To assess neurotoxicity, brain and muscle acetylcholinesterase (AChE) activities were measured. To evaluate oxidative stress, the enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione S-transferase (GST), as well as lipoperoxidation (LPO), were analyzed in liver and gills. Activity of hepatic cyclooxygenase (COX) was also evaluated. Genotoxicity was assessed in blood using comet assay and micronucleus test, as well as nuclear abnormalities. DCF and CAF, alone or combined, had neither effect on AChE activity, nor in the activity of SOD, CAT, GPx and GST in gills. In liver, DCF inhibited SOD and GPx activity, CAF inhibited CAT activity, the mixture inhibited SOD and GST activity; although only fish exposed to CAF showed increased hepatic LPO. Under these experimental conditions, no effect on COX activity was observed, nor cytotoxic and genotoxic damage. The most pronounced effects were caused by the drugs separately, since both compounds altered the enzymes, but only CAF triggered LPO, showing more harmful effects.

Influence of pesticides and abiotic conditions on biochemical biomarkers in Aegla aff. longirostri (crustacea, anomura): Implications for conservation

Freshwater ecosystems are constantly threatened by the advance of agricultural activities. Abiotic variables (such as temperature, ammonia, and nitrite) and contaminants (e.g. pesticides) can potentially interact, increasing metabolism and the absorption of toxic substances, which can alter the ability of organisms to establish adequate stress responses. This study aimed to verify which pesticides were most frequently found and in the greatest quantities in low-order streams, and whether the combination of these pesticides with the abiotic variables altered the biological metabolism of aeglids. These freshwater crustaceans are important shredders that inhabit low-order streams and are sensitive to disturbances and/or abrupt environmental variations. The animals were exposed in situ in four streams (reference site and sites 1, 2, and 3). The reference site is a preserved stream with no apparent anthropogenic interference where aeglids still occur, while the other sites no longer exhibit populations of these animals and are influenced by agricultural activities. The exposure was performed bimonthly from November 2017 to September 2018 and lasted 96 h. Measured abiotic data and water samples were collected through all days of exposure. The analyzed biochemical parameters were acetylcholinesterase activity in muscle; and glutathione S-transferase, lipid peroxidation, protein carbonylation, non-protein thiols, antioxidant capacity against peroxides, and reactive oxygen species (ROS) in muscle, gills, and hepatopancreas. We found 24 active principles of pesticides, the most frequently being clomazone, atrazine, and propoxur. Bentazone was present at the highest amounts. The parameters evaluated in this study, including biochemical biomarkers and abiotic factors measured from the water, provided a separation of the months as a function of environmental conditions. There was a difference in activity and biomarker levels throughout the year within the same site and in some months between sites. The greater concentration or variety of pesticides associated with extreme abiotic (very high temperatures) data generated increased oxidative stress, with high levels of protein damage and considerable lipid damage in all tissues, as well as elevation in ROS, even with high levels of antioxidant capacity and non-protein thiols. With these data, we intend to warn about the risks of exposure to these environmental conditions by trying to contribute to the preservation of limnic fauna, especially aeglid crabs, because most species are under some degree of threat.

Effects of paper wasp (Polistes flavus) venom toxins on lactic dehydrogenase (LDH) and acetyl cholinesterase (AChE) activity in blood serum, liver and muscles of albino mice

In the present investigation, in vivo effects of wasp toxin were evaluated on lactic dehydrogenase (LDH) and acetyl cholinesterase (AChE) enzyme activity in serum, liver and gastrocnemius muscles of albino mice. A significant elevation was observed in LDH activity in serum, liver and muscles, while the activity of AChE was decreased in serum, liver and gastrocnemius muscles of albino mice after injected the sub lethal dose of Polistes flavus venom. Increase in the activity of LDH shows liver damage, massive disintegration and necrosis of hepatic cells and leakage of the enzyme into the circulation. High LDH level causes intense stress and hypertension and did a significant increase in the rate of oxidation in animals. Therefore, elevation in LDH level increases the glucose catabolism for energy production especially in anaerobic condition. Besides this, increased level of LDH in muscle and liver cells shows insufficient oxygen supply. In experimental animals accumulation of acetylcholine may lead to prolonged activation of acetylcholine receptors and a permanent stimulation of nerves and muscle cells resulting in muscular paralysis and finally imposed death in experimental animals. Contrary to this, in vitro study of wasp venom toxins directly affected the lactic dehydrogenase activity while the venom toxin of the Polistes flavus not directly affects the acetyl cholinesterase in the serum of the albino mice.

Effects of paper wasp (Polistes flavus) venom toxins on lactic dehydrogenase (LDH) and acetyl cholinesterase (AChE) activity in blood serum, liver and muscles of albino mice

Effects of paper wasp (Polistes flavus) venom toxins on lactic dehydrogenase (LDH) and acetyl cholinesterase (AChE) activity in blood serum, liver and muscles of albino mice

Toxicological effects of anthropogenic activities in Geophagus brasiliensis from a coastal river of southern Brazil: A biomarker approach

This study aimed to assess the water quality of the Perequê River, Porto Belo, Santa Catarina, Brazil, through a biomarker approach in the native fish species Geophagus brasiliensis, and the sediment chemical quantification of the herbicides glyphosate and bentazone used in irrigated rice plantations. This river is used for the public water supply of two municipalities. The first sampling (S1) was in November 2016, in the spring season and the second (S2), in March 2017, in the fall season. In each sampling, two points of the river were analyzed, one upstream of the accumulation dam and the water catchment point for water supply of the Porto Belo WTS (P1), and another downstream (P2) with water, sediment, and fish sampling. Biotransformation, oxidative stress, histopathological and genotoxic biomarkers were analyzed in different tissues. The presence of glyphosate was detected in the sediment (11.7 μg·kg−1) from the upstream point of the water catchment site (P1) in spring. The lower activity of the antioxidant enzyme superoxide dismutase (SOD), as well as the increased damage to renal DNA and hepatic tissue, coincided with the lower muscular and cerebral acetylcholinesterase activities (AChE) at P1, in relation to P2 in the spring season, with a lower rainfall index (81.8 mm3). A seasonal variation was also observed between the spring and fall seasons, in fish responses to biomarkers. Reduction of muscle AChE activity and biotransformation enzymes ethoxyresorufin-O-deethylase and glutathione S-transferase and antioxidant enzymes such as, SOD and glutathione peroxidase, as well as increased brain DNA damage, coincided with the highest number of tissue lesions in the liver and gills in the spring, regardless of the sampling point. The results suggested that the Perequê River is contaminated by xenobiotics and probably herbicides from irrigated rice plantations, indicating damages to the biota and a potential public health risk.

Overview of the toxic effects of titanium dioxide nanoparticles in blood, liver, muscles, and brain of a Neotropical detritivorous fish.

The toxicity of titanium dioxide nanoparticles (TiO2 -NP) in the blood, liver, muscle, and brain of a Neotropical detritivorous fish, Prochilodus lineatus, was tested. Juvenile fish were exposed to 0, 1, 5, 10, and 50 mg L-1 of TiO2 -NP for 48 hours (acute exposure) or 14 days (subchronic exposure) to evaluate changes in hematology, red blood cell (RBC) genotoxicity/mutagenicity, liver function (reactive oxygen species (ROS) production, antioxidant responses, detoxification, and histopathology), acetylcholinesterase (AChE) activity in muscles and brain, and Ti bioaccumulation. TiO2 -NP did not cause genetic damage to RBC, but acutely decreased white blood cells (WBC) and increased monocytes. Subchronically, RBC decreased, mean cell volume and hemoglobin increased, and WBC and lymphocytes decreased. Therefore, NP has the potential to affect immune system and increase energy expenditure, reducing the fish's ability to avoid predator and to resist pathogens. In the liver, acute exposure decreased ROS and increased glutathione (GSH) content, while subchronic exposure decreased superoxide dismutase activity and increased glutathione-S-transferase (GST) activity and GSH content. GSH and GST seem to play an essential role in metabolizing NP and ROS, likely increasing hepatocytes' metabolic rate, which may be the cause of observed cell hypertrophy, disarrangement of hepatic cords and degenerative morphological alterations. Although most studies indicate that the kidney is responsible for metabolizing and/or eliminating TiO2 -NP, this study shows that the liver also has a main role in these processes. Nevertheless, Ti still accumulated in the liver, muscle, and brain and decreased muscular AChE activity after acute exposure, showing neurotoxic potential. More studies are needed to better understand the biochemical pathways TiO2 -NP are metabolized and how its bioaccumulation may affect fish homeostasis and survival in the environment.

Selection of biochemical and physiological parameters in the croaker Micropogonias furnieri as biomarkers of chemical contamination in estuaries using a generalized additive model (GAM)

Biochemical and physiological parameters in the croaker Micropogonias furnieri were evaluated as biomarkers of chemical contaminants in estuaries. Juvenile croakers (10–20 cm total body length) were collected in summer and winter (2011 and 2012), in two sites at the Lagoa dos Patos estuary (southern Brazil). Fish were also collected in summer (2011 and 2012) in one site at the Barra do Chui estuary (southern Brazil). Tissue (gills, muscle or liver) samples were dissected and analyzed for contaminants [metals, polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs)] and selected biochemical and physiological parameters [metallothionein-like proteins (MTLP), acetylcholinesterase (AChE) activity, ethoxyresorufin-O-deethylase (EROD) activity, and lipid peroxidation (LPO)]. Additionally, water samples were collected for water chemical analyses (salinity, pH, temperature, dissolved oxygen, total alkalinity, and sulfate concentration). Data obtained were integrated and analyzed, using Principal Component Analysis (PCA) and Generalized Additive Model (GAM) approaches. Results showed that changes in concentrations of chemical contaminants and responses of biochemical and physiological parameters did not show any pattern according to the site, season and year of fish collection. However, they were influenced by fish body length and water temperature and salinity. Liver LPO and EROD activity were not responsive to PAHs. However, liver LPO was responsive to HCB, p,p-DDD, p,p-DDT and endosulfan sulfate. In turn, gill MTLP concentration, muscle AChE activity and liver EROD activity were responsive to non-essential metals (Pb, Cd and Ag). Considering that the ecotoxicological modeling approach adopted (GAM) accounted for biological, spatial and temporal variability of data associated with fish body size and site, season and year of fish collection, gill MTLP concentration, muscle AChE activity, as well as liver LPO and EROD activity can be considered as reliable biomarkers of fish exposure to chemical contaminants in estuaries.

Spatial and temporal analysis of biliary 1-hydroxypyrene, hepatic ethoxyresorufin-O-deethylase and muscle acetylcholinesterase activity in UK flatfish

Chemical pollution of the marine environment from anthropogenic sources is a global concern due to the potential for long term effects on the ecosystem. Chemical monitoring schemes can detect harmful substances in water, sediment or biota. However, the presence of specific determinants gives no information on how individual species or the ecosystem are impacted. Biological effects techniques are therefore used in environmental monitoring schemes to provide a clearer picture of whether the chemicals present are causing deleterious effects on the species sampled, or whether organisms have been exposed to certain classes of organic contaminants that they may be able to metabolise. Using these techniques, we can provide an assessment of the health of our marine environment (Thain et al., 2008).

Effect of Sciatic Nerve Transection on acetylcholinesterase activity in spinal cord and skeletal muscles of the bullfrog Lithobates catesbeianus.

Sciatic nerve transection (SNT), a model for studying neuropathic pain, mimics the clinical symptoms of "phantom limb", a pain condition that arises in humans after amputation or transverse spinal lesions. In some vertebrate tissues, this condition decreases acetylcholinesterase (AChE) activity, the enzyme responsible for fast hydrolysis of released acetylcholine in cholinergic synapses. In spinal cord of frog Rana pipiens, this enzyme's activity was not significantly changed in the first days following ventral root transection, another model for studying neuropathic pain. An answerable question is whether SNT decreases AChE activity in spinal cord of frog Lithobates catesbeianus, a species that has been used as a model for studying SNT-induced neuropathic pain. Since each animal model has been created with a specific methodology, and the findings tend to vary widely with slight changes in the method used to induce pain, our study assessed AChE activity 3 and 10 days after complete SNT in lumbosacral spinal cord of adult male bullfrog Lithobates catesbeianus. Because there are time scale differences of motor endplate maturation in rat skeletal muscles, our study also measured the AChE activity in bullfrog tibial posticus (a postural muscle) and gastrocnemius (a typical skeletal muscle that is frequently used to study the motor system) muscles. AChE activity did not show significant changes 3 and 10 days following SNT in spinal cord. Also, no significant change occurred in AChE activity in tibial posticus and gastrocnemius muscles at day 3. However, a significant decrease was found at day 10, with reductions of 18% and 20% in tibial posticus and gastrocnemius, respectively. At present we cannot explain this change in AChE activity. While temporally different, the direction of the change was similar to that described for rats. This similarity indicates that bullfrog is a valid model for investigating AChE activity following SNT.

Soil enzyme dynamics in chlorpyrifos-treated soils under the influence of earthworms

Earthworms contribute, directly and indirectly, to contaminant biodegradation. However, most of bioremediation studies using these annelids focus on pollutant dissipation, thus disregarding the health status of the organism implied in bioremediation as well as the recovery of indicators of soil quality. A microcosm study was performed using Lumbricus terrestris to determine whether earthworm density (2 or 4individuals/kg wet soil) and the time of exposure (1, 2, 6, 12, and 18wk) could affect chlorpyrifos persistence in soil initially treated with 20mg active ingredientkg−1 wet soil. Additionally, selected earthworm biomarkers and soil enzyme activities were measured as indicators of earthworm health and soil quality, respectively. After an 18-wk incubation period, no earthworm was killed by the pesticide, but clear signs of severe intoxication were detected, i.e., 90% inhibition in muscle acetylcholinesterase and carboxylesterase (CbE) activities. Unexpectedly, the earthworm density had no significant impact on chlorpyrifos dissipation rate, for which the measured half-life ranged between 30.3d (control soils) and 44.5d (low earthworm density) or 36.7d (high earthworm density). The dynamic response of several soil enzymes to chlorpyrifos exposure was examined calculating the geometric mean and the treated-soil quality index, which are common enzyme-based indexes of microbial functional diversity. Both indexes showed a significant and linear increase of the global enzyme response after 6wk of chlorpyrifos treatment in the presence of earthworms. Examination of individual enzymes revealed that soil CbE activity could decrease chlorpyrifos-oxon impact upon the rest of enzyme activities. Although L. terrestris was found not to accelerate chlorpyrifos dissipation, a significant increase in the activity of soil enzyme activities was achieved compared with earthworm-free, chlorpyrifos-treated soils. Therefore, the inoculation of organophosphorus-contaminated soils with L. terrestris arises as a complementary bioremediation strategy in terms of recovery of soil biochemical performance and quality.

Oxidative stress in the hybrid fish jundiara (Leiarius marmoratus × Pseudoplatystoma reticulatum) exposed to Roundup Original®

The aim of this study was to investigate the effects of Roundup Original®, a glyphosate-based herbicide, against biochemical parameters including thiobarbituric acid-reactive substances (TBARS), protein carbonyl, enzymatic and nonenzymatic antioxidant responses and acetylcholinesterase (AChE) of jundiara fish (Leiarius marmoratus × Pseudoplatystoma reticulatum) at a sublethal concentration of 1.357 mg L−1. Fish exposed to the herbicide for different periods (6–96 h) showed a significant increase of both hepatic and muscular TBARS and protein carbonyl. Enzymatic antioxidant activity was decreased in the liver and brain after 48 h of exposure. Glutathione-S-tranferase (GST) had its levels raised in the brain and gills, probably as a toxicity event response. Non protein thiols (GSH) demonstrated a reduction after 6 and 24 h of exposure in the hepatic tissue, followed by an increase at 48 and 96 h in the same tissue. GSH brain levels, however, increased only after 96 h. AChE activity in muscle decreased for all the times tested (26.5, 45, 38 and 14% for 6, 24, 48 and 96 h respectively), but only at 96 h (34%) in the brain. We found that Roundup Original® is able to trigger important changes in the biochemical parameters tested, showing it can be a potential threat for the health and survival of fish in the environment.

Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water.

The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 µL L-1) and essential oil of Lippia alba (EOL) (10 or 20 µL L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 µL L-1) and EOL (10 or 20 µL L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 µL L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.