Comparative Biochemistry and Physiology C-toxicology & Pharmacology最新文献

One of the top ecological priorities is to find sensitive indicators for pollution monitoring. This study focuses on the bioconcentration and responses (condition index, survival, oxygen consumption, heart rates, and oxidative stress and neurotoxic effect biomarkers) of mussels from the Volga River basin, Dreissena polymorpha and Dreissena bugensis, to long-term exposure to toxic chemicals such as tributyltin (TBT, 25 and 100 ng/L) and copper (Cu, 100 and 1000 μg/L). We found that TBT was present in the tissues of zebra and quagga mussels in comparable amounts, whereas the bioconcentration factor of Cu varied depending on its concentration in water. Differences in responses between the two species were revealed. When exposed to high Cu concentrations or a Cu-TBT mixture, quagga mussels had a lower survival rate and a longer heart rate recovery time than zebra mussels. TBT treatment caused neurotoxicity (decreased acetylcholinesterase activity) and oxidative stress (increased levels of thiobarbituric acid reactive substances) in both species. TBT and Cu levels in mussel tissues correlated positively with the condition index, but correlated with the level of acetylcholinesterase in the mussel gills. The principal component analysis revealed three main components: the first consists of linear combinations of 14 variables reflecting TBT water pollution, TBT and Cu levels in mussel tissues, and biochemical indicators; the second includes Cu water concentration, cardiac tolerance, and mussel size; and the third combines weight, metabolic rate, and heart rates. Quagga mussels are less tolerable to contaminants than zebra mussels, so they may be used as a sensitive indicator.

Carbofuran (CF) is a carbamate class pesticide, widely used in agriculture for pest control in crops. This pesticide has high toxicity in non-target organisms, and its presence in the environment poses a threat to the ecosystem. Research has revealed that this pesticide acts as an inhibitor of acetylcholinesterase (AChE), inducing an accumulation of acetylcholine in the brain. Nonetheless, our understanding of CF impact on the central nervous system remains elusive. Therefore, this study explored how CF influences behavioral and neurochemical outcomes in adult zebrafish. The animals underwent a 96-hour exposure protocol to different concentrations of CF (5, 50, and 500 μg/L) and were subjected to the novel tank (NTT) and social preference tests (SPT). Subsequently, they were euthanized, and their brains were extracted to evaluate neurochemical markers associated with oxidative stress and AChE levels. In the NTT and SPT, CF did not alter the evaluated behavioral parameters. Furthermore, CF did not affect the levels of AChE, non-protein sulfhydryl groups, and thiobarbituric acid reactive species in the zebrafish brain. Nevertheless, further investigation is required to explore the effects of environmental exposure to this compound on non-target organisms.

Microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) are priority contaminants of marine environments. However, their combined toxic effects on aquatic organisms are still largely unclear. In this study, the toxicological effects of microplastics (MPs) and Benzo[a]pyrene (BaP), a representative PAH, on Asian sea bass Lates calcarifer was investigated. Juvenile Asian sea bass were exposed for 56 days to polyethylene MPs (0.1 and 1 mg/L) and BaP (20 and 80 μg/L) as single or combined environmental stressors. The effects of MPs and BaP exposure on fish were evaluated considering several biological indices such as growth and condition indices, the oxidative stress response in the liver, and the expression levels of genes related to the stress, immunomodulation, detoxification, and apoptosis. Exposure to MPs and BaP in single or combined experiments significantly (P < 0.05) decreased fish growth, and altered body protein content and food conversion ratio (FCR), but greater magnitudes of changes was observed in the combined experimental group of BaP80 + MP1. The activities of liver antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) decreased; meanwhile, malondialdehyde (MDA) activity was dramatically enhanced (P < 0.05). The combined groups with higher concentrations (BaP80+ MP1) caused more severe alterations in enzyme levels compared to the single exposure groups and lower concentrations. MDA was the most affected among the studied enzymes. The expression levels of functional genes involved in stress response (GPX, HSP70, HSP90), pro-inflammation (LYZ, IL-1β, IL-8, and TNF-α), and detoxification (CYP1A) displayed significant alterations as the result of exposure to MPs and BaP single and in combination. The transcription levels of functional genes were more affected in fish exposed to BaP at 80 ng/mL when combined with MPs at 1 mg/mL. Additionally, MPs and BaP heightened the expression of apoptotic-related genes (p53 and caspase-3) on day 7 of exposure in a dose-dependent synergetic manner (P < 0.05). The results of this study demonstrate that exposure to MPs and BaP alone results in significant alterations in fish growth and condition factors, and could activate the stress response, stimulate the anti-oxidative defense system, immune transcriptomic response, and apoptosis in Asian sea bass; however, MPs can enhance the adverse effects of BaP on biological markers.

Cyanobacterial blooms are worldwide distributed and threaten aquatic ecosystems and public health. The current studies mainly focus on the adverse impacts of planktonic cyanobacteria or pure cyanotoxins, while the benthic cyanobacteria-induced ecotoxic effects are relatively lacking. The cyanobacterial cell-induced toxic effects on aquatic organisms might be more serious and complex than the pure cyanotoxins and crude extracts of cyanobacteria. This study explored the chronic effects of toxin-producing planktonic Microcystis aeruginosa (producing microcystin) and benthic Oscillatoria sp. (producing cylindrospermopsin) on the behaviors, tissue structures, oxidative stress, apoptosis, and inflammation of the Asian clams (Corbicula fluminea) under 28-d exposure. The data showed that both M. aeruginosa and Oscillatoria sp. can decrease the behaviors associated with the feeding activity and induce tissue damage (i.e. gill and digestive gland) in clams. Furthermore, two kinds of cyanobacteria can alter the antioxidant enzyme activities and increase antioxidant, lipid oxidation product, and neurotransmitter degrading enzyme levels in clams. Moreover, two kinds of cyanobacteria can activate apoptosis-related enzyme activities and enhance the proinflammatory cytokine levels of clams. In addition, two kinds of cyanobacteria can disturb the transcript levels of genes linked with oxidative stress, apoptosis, and inflammation. These results suggested harmful cyanobacteria can threaten the survival and health of clams, while the benthic cyanobacteria-induced adverse effects deserve more attention. Our finding also indicated that it is necessary to focus on the entire algal cell-induced ecotoxicity when concerning the ecological impacts of cyanobacterial blooms.

Tizoxanide (TZX) is an active metabolite of nitazoxanide (NTZ) originally developed as an antiparasitic agent, and is predominantly metabolized into TZX glucuronide. In the present study, TZX glucuronidation by the liver and intestinal microsomes of humans, monkeys, dogs, rats, and mice, and recombinant human UDP-glucuronosyltransferase (UGT) were examined. The kinetics of TZX glucuronidation by the liver and intestinal microsomes followed the Michaelis–Menten or biphasic model, with species-specific variations in the intrinsic clearance (CL_int). Rats and mice exhibited the highest CL_int values for liver microsomes, while mice and rats were the highest for intestinal microsomes. Among human UGTs, UGT1A1 and UGT1A8 demonstrated significant glucuronidation activity. Estradiol and emodin inhibited TZX glucuronidation activities in the human liver and intestinal microsomes in a dose-dependent manner, with emodin showing stronger inhibition in the intestinal microsomes. These results suggest that the roles of UGT enzymes in TZX glucuronidation in the liver and small intestine differ extensively across species and that UGT1A1 and/or UGT1A8 mainly contribute to the metabolism and elimination of TZX in humans. This study presents the relevant and novel-appreciative report on TZX metabolism catalyzed by UGT enzymes, which may aid in the assessment of the antiparasitic, antibacterial, and antiviral activities of NTZ for the treatment of various infections.

Given that Agaricus bisporus, an edible mushroom, has demonstrated antioxidant properties, our investigation aimed to assess whether Agaricus bisporus could mitigate the toxic effects of lead (Pb) on Caenorhabditis elegans (C. elegans) model. A dose-response study was conducted involving Pb and Agaricus bisporus to determine appropriate doses. Subsequently, a co-exposure study utilizing C. elegans strains N2 and CL2166 was implemented, with groups designated as Control, Pb, Agaricus bisporus, and Pb + Agaricus bisporus. Our findings revealed that co-exposure to Pb + 100 mg/mL Agaricus bisporus resulted in reduced embryonic and larval lethality, increased brood size, and enhanced motility compared to nematodes exposed solely to Pb. Notably, our observations indicated a transfer of reproductive toxicity from nematode parents to their offspring. Thus, Agaricus bisporus may play a significant role in Pb detoxification, suggesting its potential as a natural antioxidant for neutralizing the detrimental effects of Pb on reproductive health.

Ivermectin (IVM) is a broad-spectrum veterinary antiparasitic used worldwide in cattle breeding. The aim of this study was to evaluate the lethal effects of the active ingredient and a commercial formulation of IVM (1 % active ingredient) in the embryonic stage (S. 4–6) and larval stage (S. 25) of the South American amphibian Rhinella arenarum through chronic standardized bioassays. Also, behavior analysis and oxidative stress and cholinergic effects biomarkers were analyzed at 1, 10 and 100 μg IVM/L concentrations. For the embryonic stage, the active ingredient (96 h- LC₅₀: 15900 μg/L) was more toxic than the commercial formulation (96 h-LC₅₀: 51230 μg/L) during the acute period, while at chronic exposure the commercial formulation was more toxic (504 h-LC₅₀: 10.25 μg/L), compared to the active ingredient (504 h-LC₅₀: 312.80 μg/L). For the larval stage, in acute exposure, the active ingredient (96 h-LC₅₀: 800 μg/L) was more toxic than the commercial formulation (96 h-LC₅₀: 1550 μg/L). In the chronic exposure, the commercial formulation (504 h-LC₅₀: 77.33 μg/L) was more toxic than the active ingredient (504 h-LC₅₀: 195.25 μg/L). Overall, larvae exhibited greater sensitivity to both the active ingredient and the commercial formulation. However, during chronic exposure, embryos were more sensitive to the commercial formulation than larvae. The commercial formulation primarily induced oxidative stress, and both forms of the compound affected behavior and cholinergic effect biomarkers, even at low environmentally relevant concentrations (1 μg/L). These results highlight the potential impact of IVM on aquatic ecosystems.

Pesticides used in rice cultivation can cause negative health effects to non-target organisms representative of natural biodiversity. In this context, the present study aimed to investigate the occurrence of pesticides in surface waters from a river that flows in the middle of a rice farming-dominated area. We were also interested in evaluate biochemical and histological effects caused by exposure (16 d) to the lower and higher concentrations of the main found herbicide (bentazone, BTZ), insecticide (chlorantraniliprole, CTP) and fungicide (tebuconazole, TBZ), isolated or mixed, in Boana faber tadpoles. No significant differences were observed in the development of the animals. Tadpoles exposed to the herbicide BTZ showed higher hepatic levels of malondialdehyde (MDA). In animals exposed to CTP, MDA levels were lower than controls. Animals exposed to the fungicide TBZ showed higher hepatic activity of glutathione S-transferase and carboxylesterase (CbE), as well as higher levels of carbonyl proteins and MDA. Animals exposed to Mix showed higher activity in CbE and glucose-6-phosphate dehydrogenase activity in the liver, as well as higher levels of MDA. In the brain and muscle of tadpoles exposed to Mix, acetylcholinesterase activity was higher. Histological changes were also observed in pesticide-exposed animals, such as increased occurrence of melanomacrophages, inflammatory infiltrates and congestion. Our data evidences the contamination of natural aquatic environments by rice pesticides, and the adverse effects of main ones in B. faber tadpoles, which suggests the contribution of pesticides derived from rice cultivation to the degradation of local biodiversity health.

The current research investigates individual and combined toxicity effects of nickel (Ni) and imidacloprid (IMI) on earthworm species Eisenia fetida fetida. Employing standardized toxicity parameters, we assessed the impact of environmentally relevant concentrations (ERC) of Ni, IMI, and their mixtures on key biomarkers and reproductive fitness of earthworms. Our findings reveal concentration-dependent responses with discernible adverse effects on physiological parameters. The ERC obtained for Ni was 0.095 ppm, and for imidacloprid was 0.01 ppm. Two concentrations (ERC and 1/5th) of both toxicants (individually and in combinations) were further given for 14 days, and parameters like avoidance behaviour, antioxidants, histology, and metabolomic profile were observed. The behaviour of earthworms was noted, where at 24–48 h, it was found to be in control soil, while later, at 72–96 h, they migrated to toxicants-treated soil. Levels of antioxidants (superoxide dismutase, catalase, reduced glutathione, ascorbic acid), lipid peroxidation, and lactate dehydrogenase were elevated in the testis, spermatheca, ovary, and prostate gland in a high concentration of Ni + IMI. Histological studies showed more vacuolization and disruption of epithelium that was increased in the prostate gland of the Ni + IMI high group, decreased number of spermatids, and damaged cell architecture was noted in testis and spermatheca of the Ni + IMI high group. The highest number of metabolites was found in Ni exposed group (181), followed by IMI (131) and Control (125). Thus, this study sheds light on the ecotoxicological effects of combinational exposure of these contaminants on an essential soil-dwelling organism, where IMI was more toxic than Ni, and both toxicants decreased earthworm reproductive fecundity.

Diesel particulate extract (DPE), which is a significant constituent of airborne particle pollution, has a strong association with the development of cancer and respiratory diseases. Fulvic acid (FA), a plentiful organic macromolecule found in water, has the capability to modify particle surface charge and adsorption capacity when combined with minerals. Nevertheless, there is a scarcity of data regarding the influence of their interaction on DPE toxicity. To examine the impact of environmental factor on the toxic effects of DPE, we used the Caenorhabditis elegans (C. elegans) model to investigate the reproductive toxicity of DPE and FA on insulin signaling pathway. C. elegans were subjected to a semi-fluid medium (NGG) containing different concentrations of DPE or DPE + FA in order to assess germline apoptosis and the expression of important genes in the insulin signaling pathway. Through several mutant strains, we found that daf-2, age-1, pdk-1, akt-1 and daf-16 were involved in DPE-induced apoptosis. Furthermore, and the expression levels of these genes significantly altered. The ratio of daf-16 translocation to nucleation, as well as the amount of reactive oxygen species (ROS), exhibited a dose-response relationship, however, the presence of FA could altered these effects. The results revealed that the insulin signaling pathway plays a vital role in mediating the harmful effects caused by DPE, whereas environmental factors have a substantial impact on its toxicity. Moreover, it was noted that semi-fluid medium could effectively replicate three-dimensional exposure circumstances closely resembling those observed in actual situations.