Utility of the TBARS assay in detecting oxidative stress in white sucker (Catostomus commersoni) populations exposed to pulp mill effluent

Environmental health in the upper-middle Luján River basin from a multi-biomarker approach

The objectives of this study were to evaluate the ecophysiological state of the biota using a set of biomarkers in the upper-middle Luján River. To this aim, we collected adult Cnesterodon decemmaculatus fish, biofilm and water at three sampling sites in the upper-middle Luján River (S1: rural area, S2: Luján City and S3: urban area after passing Lujan City). For each site we determined physicochemical variables, heavy metal concentration in water, 19 biomarkers in fish (morphometric, histological, genotoxic, oxidative stress, metabolic and neurotoxic) and six biomarkers in biofilm (oxidative stress and extracellular enzyme). Additionally, we compared the responses of fish and biofilm with those of laboratory controls obtained from outdoor cultures. Our results indicated increased heavy metal concentration at all sites, mainly As and Cd, and decreased dissolved oxygen at S1 and S3. In fish, genotoxic biomarkers showed significant differences with respect to the control. The comet assay indicated damage in fish at the urbanized sites (S2 and S3) and an increased frequency of erythrocytes with nuclear aberrations at all sites. The CEA index (cellular energy allocation), calculated from the metabolic biomarkers and lipid concentration were significantly increased at S1. The gill damage evaluated histologically and with three indices indicated severe damage at all sites. Gills showed thickened primary and secondary lamellae and fusion of filaments at all sites, but a significant increase in mucous cells was only found at S1 and S3. Biofilm showed increased values of extracellular enzymes (β-glucosidase and alkaline phosphatase, lipid peroxidation and oxidative stress enzymes (i.e., catalase) at S3. These results are novel in that they incorporated laboratory controls allowing for comparisons with fish and biofilm from the field. They provided information on the status of a fish population and biofilm community, indicating the negative effect of river water deterioration on the tested organisms. Moreover, results showed what biomarkers were most sensitive for each biological sample.

Temperature, dietary lipids, and Aeromonas hydrophila modulate self-protection mechanisms in pacu Piaractus mesopotamicus Holmberg 1887

Water temperature has a direct influence on several physiological processes in fish. This study investigated the effects of the exposure of pacu (Piaractus mesopotamicus) to 10 days of reduced temperature in stress and innate immune and antioxidant systems, all of which are involved in energy mobilization. Two groups of fish, fed a control diet or a diet with a higher lipid level, were exposed for 10 days to 16°C and then inoculated with Aeromonas hydrophila bacterin. Samples were taken before and after 5 and 10 days of exposure. The results showed that the low temperature (16°C) was a stressor, increasing cortisol levels. Higher levels of cortisol were seen in fish with more body fat, especially at 16°C, compared to those fed control diet. The immune system was enhanced by low temperature that activated the hemolytic activity of the complement system (HAC50) and lysozyme after 10 days of exposure in fish with more body fat. Bacterin inoculation, regardless of temperature and body fat, impaired the respiratory activity of leukocytes, but the complement system activity remained at the levels seen before cold activation. Similarly, lysozyme remained at the levels seen before cold activation, showing later activation. Furthermore, soon after inoculation (at 3 and 6 h), bacterin induced oxidative stress that decreased at 24 h when the concentration of reduced glutathione (GSH) showed lower levels, suggesting that GSH was consumed to attenuate the oxidative stress. Pacu was resilient to the reduced temperature, displaying protective responses to the stressful condition using lipids to modulate these responses.

Assessing habitat selection in the prawn Macrobrachium rosenbergii using the model toxicant copper and colonization as a test endpoint: Does prior exposure determine biochemical and behavioral responses?

Habitat selection by aquatic organisms is dependent on the availability of adequate conditions to support life and the benefits that the habitat provides. Contaminated environments tend to be less attractive to organisms because reduced habitat quality leads to increased maintenance costs. Consequently, reduced colonization of such disturbed habitats is an expected response. However, colonization has been understudied as an ecotoxicological test endpoint, despite its proven ability to assess habitat selection by populations across various taxa. The aim of the present study was to investigate whether previous exposure to copper could alter the colonization behavior of the freshwater prawn Macrobrachium rosenbergii along a non-forced exposure gradient of interconnected copper-contaminated habitats (0 to 500 µg/L) due to physiological and behavioral impairments. To assess this, post-larvae of M. rosenbergii were pre-exposed to 0, 50, 250 and 500 µg/L copper for a maximum period of 48 h. The physiological status and motility of the organisms after pre-exposure to copper were evaluated using behavioral endpoints (swimming activity by video tracking) and biochemical biomarkers (biotransformation, oxidative stress and neurotoxicity). The results indicated that pre-exposure to copper (at concentrations of 0, 50 and 500 µg/L) significantly influenced the median colonization concentration (CC50), which decreased from 270 µg/L to 109 µg/L. None of the assessed swimming parameters (speed, motility rate, exploration rate, and total distance) were affected by the pre-exposure to copper (0, 50 and 250 µg/L). Biochemically, cholinesterase levels were only affected in the prawn population exposed to 250 µg/L of copper. The present study provides a better understanding of the relevance of colonization as an ecotoxicological endpoint for assessing the spatial distribution of populations, including both new inhabitants and previously exposed organisms, in recovering habitats.

The use of chitosan as an antioxidant in the feed of cultivated P. vannamei shrimp against oxidative stress induced by exposure to microplastics

Microplastics (MP) are omnipresent in aquaculture and can induce several toxic effects, mainly oxidative stress. Therefore, alternatives to minimize these effects are welcome. In this study, chitosan (1 and 3 g/kg) was supplemented through the feed of farmed shrimp P. vannamei for 30 days. After this period, the shrimp were exposed to MP (0.5 mg/L) for 7 days. The results showed the presence of MP in hepatopancreas, gills and muscle. Hepatopancreas morphological alterations, as well as lipid peroxidation, a decrease in GSH level, and an increase in SOD activity indicated an oxidative stress that was reversed by chitosan. The muscle was also affected by MP, showing decreased CAT activity and increased SOD activity, though no lipid peroxidation was observed. In muscle, chitosan reversed the SOD increase to basal activity. The results obtained showed that chitosan was more effective against oxidative stress than in preventing accumulation and histological damage.

Natural modulation of redox status throughout the ontogeny of Amazon frog Physalaemus ephippifer (Anura, Leptodactylidae)

During their development, amphibians undergo various physiological processes that may affect their susceptibility to environmental pollutants. Naturally occurring fluctuations caused by developmental events are often overlooked in ecotoxicological studies. Our aim is to investigate how biomarkers of oxidative stress are modulated at different stages of larval development in the Amazonian amphibian species, Physalaemus ephippifer. The premetamorphosis, prometamorphosis and metamorphic climax stages were used to analyze total antioxidant capacity (ACAP), glutathione S-transferase (GST) activity, lipid peroxidation (LPO) levels and the expression of genes nrf2, gst, gsr (glutathione reductase) and gclc (glycine-cysteine ligase, catalytic subunit). Although there was no difference in ACAP and the genes expression among the studied stages, individuals from the premetamorphosis and prometamorphosis showed higher GST activity than ones under the climax. LPO levels were highest in individuals from the metamorphic climax. The present study suggests that the oxidative status changes during ontogeny of P. ephippifer tadpoles, especially during the metamorphic climax, the most demanding developmental phase. Variations in the redox balance at different developmental stages may lead to a divergent response to pollution. Therefore, we recommend that studies using anuran larvae as biomonitors consider possible physiological differences during ontogeny in their respective analyses.

Can photoperiod improve growth performance and antioxidant responses of pacu (Piaractus mesopotamicus) reared in recirculation aquaculture systems?

The present study investigated the best photoperiod for culturing pacu (Piaractus mesopotamicus) in recirculation aquaculture systems (RAS) based on its growth performance and hematological and oxidative stress responses. Juveniles (∼ 5 g) were subjected to five treatments (in triplicate): 24 L (light):0D (dark), 15 L: 09D, 12 L:12D, 9 L:15D, and 0 L:24D for 45 days. A total of 225 pacu individuals were randomly distributed among 15 tanks of 210 L (n = 15 per tank). Zootechnical, hematological (glucose, lactate, hematocrit, and hemoglobin), and antioxidant and oxidative stress parameters (glutathione S-transferase (GST), total antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were analyzed. The zootechnical parameters (e.g., weight gain, Fulton's condition factor, and specific growth rate) were better and worse with 9 L:15D and 24 L:0D photoperiods, respectively. The hepatosomatic index was higher and lower in the 0 L:24D and 9 L:15D photoperiods. Blood lactate levels and antioxidant and oxidative stress responses were increased in the longest photoperiods (15 L:9D and 24 L:0D). In contrast, the treatments that showed lower oxidative damage (liver, gills, brain, and muscle) were 9 L:15D and 12 L:12D. In conclusion, manipulating artificial light is one way to improve fish growth and health, where the best photoperiod for pacu farming in RAS is 9 L:15D.

Noise accelerates embryonic development in a key crab species: Morphological and physiological carryover effects on early life stages

Anthropogenic noise is considered one important global pollutant. The impact of noise on marine invertebrates has been less assessed. The present study evaluated the chronic effect of the motorboat noise obtained from a lagoon's soundscape, the natural habitat of the key crab Neohelice granulata, on its whole embryonic development, considering morphological and physiological carryover effects on embryos and hatched larvae. Results demonstrated that embryonic development was shortened under noise exposure. The effects on advanced embryos, larvae and adult females were: increased heartbeats and non-viable eggs, and decreased fecundity. Biochemical responses showed lipid peroxidation in embryos while antioxidant enzymes were activated in larvae and adults, indicating a counteracting effect related to the life stage. The negative effects on fitness offspring may imply ecological consequences at the population level. Results are discussed in terms of the ecosystem engineer species studied and the habitat, a MAB UNESCO Reserve lagoon, suggesting the urgent need to develop mitigation plans.

Incorporating vertical movement of fishes in habitat use models

Fish telemetry studies now routinely collect positional and depth data, yet analytical approaches that integrate three-dimensional data are limited. Here we apply the potential path volume (PPV) model, a method previously developed to estimate habitat volume based on rates of avian movement, to free-swimming fish. Using a telemetry dataset of white sucker (Catastomus commersonii) from Turkey Lake (Ontario, Canada), we evaluated the effects of the number of spatial positions and different methods of selecting swim speed (vswim), a key parameter for PPV models, on habitat volume estimates. We subsequently compared habitat volume estimates and habitat overlap among white sucker pairs from the PPV models to those calculated using kernel utilization distribution-based approaches. The number of spatial positions in the PPV model had a significant effect on habitat volume estimates, whereas the magnitude of the vswim parameter or its specificity (constant value vs. fish-season specific parameter values) did not affect habitat volume estimates. The PPV method resulted in larger habitat volume estimates and greater habitat overlap estimates among fish pairs relative to those obtained from a three-dimensional kernel utilization distribution method. The PPV model is a useful analytical tool that, by incorporating potential animal movement into habitat use evaluations, can help answer key ecological questions and provide insight into fish space use in a wide range of conservation and management applications.

Impact of antiparasitic used in livestock: effects of ivermectin spiked sediment in Prochilodus lineatus, an inland fishery species of South America

Ivermectin (IVM) is a widely used antiparasitic. Concerns have been raised about its environmental effects in the wetlands of Río de la Plata basin where cattle have been treated with IVM for years. This study investigated the sublethal effects of environmentally relevant IVM concentrations in sediments on the Neotropical fish Prochilodus lineatus. Juvenile P. lineatus were exposed to IVM-spiked sediments (2 and 20 µg/Kg) for 14 days, alongside a control sediment treatment without IVM. Biochemical and oxidative stress responses were assessed in brain, gills, and liver tissues, including lipid damage, glutathione levels, enzyme activities, and antioxidant competence. Muscle and brain acetylcholinesterase activity (AChE) and stable isotopes of 13C and 15N in muscle were also measured. The lowest IVM treatment resulted in an increase in brain lipid peroxidation, as measured by thiobarbituric acid reactive substances (TBARs), decreased levels of reduced glutathione (GSH) in gills and liver, increased catalase activity (CAT) in the liver, and decreased antioxidant capacity against peroxyl radicals (ACAP) in gills and liver. The highest IVM treatment significantly reduced GSH in the liver. Muscle (AChE) was decreased in both treatments. Multivariate analysis showed significant overall effects in the liver tissue, followed by gills and brain. These findings demonstrate the sublethal effects of IVM in P. lineatus, emphasizing the importance of considering sediment contamination and trophic habits in realistic exposure scenarios.

Can environmental factors increase oxidative responses in fish exposed to polycyclic aromatic hydrocarbons (PAHs)?

Relations among polycyclic aromatic hydrocarbons (PAHs), biomarkers of oxidative stress (lipid peroxidation, glutathione, and glutathione S-transferase activity), and the possible influence of environmental factors (temperature, pH, and salinity) were assessed in situ for specimens of Ramnogaster arcuata, a native estuarine fish. PAH levels found in the muscular tissue of R. arcuata ranged from 0.7 to 293.4 ng g-1 wet weight with petrogenic and pyrolytic inputs. Lipid peroxidation in the liver showed positive correlations (P < 0.05) with total PAHs (r = 0.66), 3-ring (r = 0.66) and 4-ring PAHs (r = 0.52) and glutathione in muscle (r = 0.58). Significant positive correlations (P < 0.05) were also evidenced between muscular glutathione with total (r = 0.62) and 3-ring PAHs (r = 0.75). Hepatic glutathione S-transferase negatively correlated with 4-ring PAHs (r = -0.58). These correlations suggest that lipid peroxidation and muscular glutathione could be good biomarkers for complex mixtures of PAHs, and hepatic glutathione S-transferase could be a suitable biomarker for 4-ring PAHs. Furthermore, significant correlations (P < 0.05) of environmental factors with PAH levels and biomarkers were observed, especially pH with 3-ring PAHs (r = -0.65), lipid peroxidation (r = -0.6), glutathione in the liver (r = -0.73) and muscle (r = -0.75); and temperature with 2-ring PAHs (r = -0.75) and glutathione in muscle (r = 0.51). The data suggest an influence of physicochemical parameters which could be driving a shift in PAH toxicity in R. arcuata. These results are essential for an integrated understanding of ecotoxicology and could help to predict environmental effects in present and future scenarios of ocean warming and acidification.

Organic contamination and multi-biomarker assessment in watersheds of the southern Brazil: an integrated approach using fish from the Astyanax genus

We aimed to examine the responses of pollution biomarkers in feral fish from Astyanax genus collected at three hydrographic regions in southern Brazil and the capacity of these tools to differentiate between various levels of contamination. To achieve this, levels of organochlorine pesticides (liver), as well as the biomarkers AChE (muscle and brain), TBARS (liver), and EROD (liver) were assessed. Collections were conducted in four municipalities (Alegrete, Caraá, Lavras, and Santa Vitória) during 1 year, encompassing winter and summer. Fish from Alegrete were the most contaminated overall, but animals sampled in Caraá, and Lavras also displayed elevated levels of current-use pesticides. Elevated levels of endosulfans, DDTs, HCHs, and current-use pesticides were accompanied by elevated levels of TBARS in the liver. Conversely, fish from Santa Vitória exhibited the highest levels of PAHs, accompanied by elevated levels of EROD in the liver and reduced levels of AChE in muscle and brain. TBARS proved to be a reliable biomarker for assessing impacts arising from pesticide accumulation, while EROD and AChE served as valuable indicators of impacts resulting from PAHs accumulation. Ultimately, the results obtained in this study demonstrate the reliable use of the proposed biomarkers for tracking biological impacts stemming from aquatic pollution using feral Astyanax as biomonitoring species.

Integrated biomarker responses in wild populations of the intertidal sea anemone Bunodosoma zamponii living under different anthropogenic pressures

Bunodosoma zamponii is the most abundant anemone in Mar del Plata (Buenos Aires, Argentina). Given that the presence of persistent organic pollutants (organochlorine pesticides and PCBs) and the organophosphate pesticide chlorpyrifos has recently been reported in this species, two wild populations living under different anthropogenic pressures were studied and compared regarding basic aspects of their ecology and physiological response to oxidative stress. A population from an impacted site (Las Delicias, LD) and another from a reference site (Punta Cantera, PC) were monitored seasonally (spring, summer, autumn, and winter), for one year. Anemones from PC were larger and more abundant than those from LD for most sampling periods. During winter, glutathione-S-transferase and catalase activities were higher in LD. Moreover, protein content and antioxidant defenses were higher in anemones from PC during winter as well. Taking into account their ecology (size and abundance) and biomarker responses, the population from PC was comparatively healthier. Furthermore, such differences are in agreement with recent studies indicating a higher concentration of pollutants in anemones from LD (specially during the winter sampling). In this sense, considering that B. zamponii can bioaccumulate the aforementioned pollutants, its resilience to their presence, and the fact that biomarker response differed between sites, this species can be regarded as a proper sentinel species of environmental pollution. Overall, this anemone seems to be a good bioindicator to be considered in future biomonitoring and ecotoxicological studies.

Usefulness of oxidative stress biomarkers in native species for the biomonitoring of pesticide pollution in a shallow lake of the Austral Pampas, Argentina

Pesticide contamination and its adverse effects on native freshwater species continue to be a worldwide major concern, mainly in developing countries. Passive biomonitoring of pesticide pollution in shallow lakes may be achieved by the simultaneous use of fish and wetland plants. Thus, the present study aimed to evaluate the occurrence of current-use pesticides in the surface water of a shallow lake of the Austral Pampas region (Buenos Aires Province, Argentina) surrounded by intensive agricultural activities and its relationship with a battery of biomarkers, including oxidative stress and genotoxicity, in two native species, the fish Oligosarcus jenynsii and the macrophyte Bidens laevis. A total of 26 pesticide residues were analyzed, and the main ones detected were glyphosate and its metabolite aminomethylphosphonic acid (AMPA), chlorpyrifos, and imidacloprid. In O. jenynsii, hydrogen peroxide (H2O2) content in the liver increased with chlorpyrifos occurrence, while malondialdehyde (MDA) levels in the brain and liver increased with the presence of both chlorpyrifos and glyphosate. In B. laevis, H2O2 and MDA levels in leaves and roots increased with AMPA occurrence. Also, leaf H2O2 contents and root MDA levels increased with chlorpyrifos concentration. In contrast, catalase and peroxidase activities in roots decreased with AMPA and chlorpyrifos occurrence. In both species, mainly H2O2 and MDA levels demonstrated their sensitivity to be used as biomarkers in the biomonitoring of current-use pesticide pollution in shallow lakes. Their use may provide information to plan strategies for environmental conservation by government institutions or decision-makers, and to assess the biota health status.

Increased coral biomineralization due to enhanced symbiotic activity upon volcanic ash exposure

Coral reefs, which are among the most productive ecosystems on earth, are in global decline due to rapid climate change. Volcanic activity also results in extreme environmental changes at local to global scales, and may have significant impacts on coral reefs compared to other natural disturbances. During explosive eruptions, large amounts of volcanic ash are generated, significantly disrupting ecosystems close to a volcano, and depositing ash over distal areas (10s - 1000s of km depending on i.a. eruption size and wind direction). Once volcanic ash interacts with seawater, the dissolution of metals leads to a rapid change in the geochemical properties of the seawater column. Here, we report the first known effects of volcanic ash on the physiology and elemental cycling of a symbiotic scleractinian coral under laboratory conditions. Nubbins of the branching coral Stylophora pistillata were reared in aquaria under controlled conditions (insolation, temperature, and pH), while environmental parameters, effective quantum yield, and skeletal growth rate were monitored. Half the aquaria were exposed to volcanic ash every other day for 6 weeks (250 mg L-1 week-1), which induced significant changes in the fluorescence-derived photochemical parameters (ΦPSII, Fv/Fm, NPQ, rETR), directly enhanced the efficiency of symbiont photosynthesis (Pg, Pn), and lead to increased biomineralization rates. Enhancement of symbiont photosynthesis is induced by the supply of essential metals (Fe and Mn), derived from volcanic ash leaching in ambient seawater or within the organism following ingestion. The beneficial role of volcanic ash as an important micronutrient source is supported by the fact that neither photophysiological stress nor signs of lipid peroxidation were detected. Subaerial volcanism affects micronutrient cycling in the coral ecosystem, but the implication for coral ecophysiology on a reef scale remains to be tested. Nevertheless, exposure to volcanic ash can improve coral health and thus influence resilience to external stressors.

Toxic effects of environmental-relevant exposure to polyethylene terephthalate (PET) micro and nanoparticles in zebrafish early development

Polyethylene terephthalate (PET) is a commonly used thermoplastic in industry due to its excellent malleability and thermal stability, making it extensively employed in packaging manufacturing. Inadequate disposal of PET packaging in the environment and natural physical-chemical processes leads to the formation of smaller particles known as PET micro and nanoplastics (MNPs). The reduced dimensions enhance particle bioavailability and, subsequently, their reactivity. This study involved chemical degradation of PET using trifluoroacetic acid to assess the impact of exposure to varying concentrations of PET MNPs (0.5, 1, 5, 10, and 20 mg/L) on morphological, functional, behavioral, and biochemical parameters during the early developmental stages of zebrafish (Danio rerio). Characterization of the degraded PET revealed the generated microplastics (MPs) ranged in size from 1305 to 2032 μm, and that the generated nanoplastics (NPs) ranged from 68.06 to 955 nm. These particles were then used for animal exposure. After a six-day exposure period, our findings indicate that PET MNPs can diminish spontaneous tail coiling (STC), elevate the heart rate, accumulate on the chorion surface, and reduce interocular distance. These results suggest that PET exposure induces primary toxic effects on zebrafish embryo-larval stage of development.

Enterocytozoon hepatopenaei (EHP) Infection Alters the Metabolic Processes and Induces Oxidative Stress in Penaeus vannamei

Enterocytozoon hepatopenaei (EHP) is highly contagious and can cause hepatopancreatic microsporidiosis (HPM), which is typically characterized by the slow growth of shrimp. In this study, the differences in histology, metabolism, oxidative stress and growth between healthy and EHP-infected Penaeus vannamei were analyzed using an EHP challenge experiment. Histology showed that EHP caused lesions in the hepatic tubules of P. vannamei, such as hepatic tubular atrophy and epithelial cell shedding, with mature spores. Meanwhile, white feces may appear when the infection is severe. Furthermore, the content of total protein, glycogen, ATP and glucose in the EHP challenge group was significantly reduced. The qPCR results showed that EHP infection changed the expression of key genes in glucose metabolism, among which hexokinase (HK), phosphofructokinase (PFK), pyruvatekinase (PK), citrate synthase (CS) and isocitric dehydrogenase (IDH) were significantly down-regulated, while phosphoenolpyruvate carboxykinase (PEPCK), fructose bisphosphatase (FBP) and glucose-6-phosphatase (G6P) were significantly up-regulated. Obviously, the expression of growth-related genes was disordered. Simultaneously, the antioxidant genes manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPX), glutathione-S-transferases (GST) and nuclear factor E2-related factor2 (Nrf2) were up-regulated to varying degrees in the EHP challenge group, and EHP infection induced significant increases in the oxidative damage products lipid peroxide (LPO) and malondialdehyde (MDA). Ultimately, the shrimp weight of the challenge group was 6.85 ± 0.86 g, which was significantly lower than that of the control group (8.95 ± 0.75 g). Taken together, we speculate that EHP changes the substance metabolism and growth process by causing oxidative damage to the hepatopancreas, which may lead to the growth retardation of P. vannamei.

Effects of Lyophilized Açaí (Euterpe oleracea) Supplementation on Oxidative Damage and Intestinal Histology in Juvenile Shrimp Penaeus vannamei Reared in Biofloc Systems

The objective of this was to evaluate the ability of bioflocs to assimilate and transfer antioxidant compounds present in açaí Euterpe oleracea to juvenile Penaeus vannamei shrimp grown in a biofloc system. Juvenile shrimp were distributed into four treatment groups (control, 5, 20, and 80 mg açaí L-1), containing 31 shrimps/tank (90 L), and cultivated for 30 days. Every 24 h throughout the experimental period, the respective açaí concentrations were added directly to the cultivation water. The bioflocs and hepatopancreas lost their antioxidant capacity with increasing concentrations of açaí; however, lipid damage was mitigated after treatment with 20 mg of açaí L-1 (p < 0.05). The application of 20 mg açaí L-1 increased the mean height and area of the middle intestinal microvilli (p < 0.05). Mortality and protein and lipid damage in shrimp muscle increased with daily administration of 80 mg açaí L-1 (p < 0.05). It is concluded that the bioflocs were able to assimilate the antioxidants present in açaí and transfer them to the shrimp, and the administration of 20 mg açaí L-1 presented the best performance, demonstrating the possibility of its application in the cultivation of P. vannamei in a biofloc system.

Can the Herbicide Dicamba Produce Oxidative Stress in the Native South American fish Jenynsia lineata at Environmentally Relevant Concentrations?

Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H2O2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish.

Oxidative effects of consuming microplastics in different tissues of white shrimp Litopenaeus vannamei

In this study, we evaluated the effect of microplastic (MP, polystyrene, 1.1 μm) exposure through diet at two different levels (40 and 400 μg MP/kg of ration) in the shrimp Litopenaeus vannamei for seven days. After the exposure period, oxidative stress parameters, histological alterations, and MP accumulation in different shrimp tissues (gut, gills, hepatopancreas, and muscle) were also evaluated. The results showed that MP was detected in the gills, muscles, and hepatopancreas. In addition, in the gut, gills, and hepatopancreas, disruption in redox cells was observed. Also, lipid and DNA damage was evident in the hepatopancreas. Histopathological analysis revealed edema in the intestine, hepatopancreas, and in the muscle. Granuloma formation with infiltrated hemocytes occurred in the intestine and hepatopancreas. These results show that MP exposure can affect the health and welfare of L. vannamei and may also affect the final consumers once MP is accumulated.

Multigenerational effects of co-exposure to dimethylarsinic acid and polystyrene microplastics on the nematode Caenorhabditis elegans

In the current study, we assessed the impact of DMA (dimethylarsinic acid) and MPs (microplastics) interactions in C. elegans over the course of five generations. We found that the redox state of the organisms changed over generations as a result of exposure to both pollutants. From the third generation onward, exposure to MPs reduced GST activity, indicating reduced detoxifying abilities of these organisms. Additionally, dimethylarsinic exposure decreased the growth of organisms in the second, fourth, and fifth generations. In comparison to isolated pollutants, the cumulative effects of co-exposure to DMA and MPs seem to have been more harmful to the organisms, as demonstrated by correlation analysis. These findings demonstrate that DMA, despite being considered less hazardous than its inorganic equivalents, can still have toxic effects on species at low concentrations and the presence of MPs, can worsen these effects.

Biochemical and physiological effects of multigenerational exposure to spheric polystyrene microplastics in Caenorhabditis elegans

Although studies have already shown the effects of exposure to microplastics (MP) in different species, the effects over generations in these individuals remain poorly understood. Therefore, the present study aimed to evaluate the effect of polystyrene MP (spherical, 1 μm) on the responses of the free-living nematode Caenorhabditis elegans in a multigenerational approach over five subsequent generations. MP concentrations of both 5 and 50 μg/L induced a detoxification response, increasing glutathione S-transferase (GST) activity and inducing the generation of reactive oxygen species (ROS) and lipid peroxidation (TBARS). MP also demonstrated the ability to accumulate in the animal's body during the 96 h of each generational exposure, and possibly, this constant interaction was the main reason for the decreased response in physiological parameters as in the exploratory behavior (body bending) of nematodes, and in the reproduction, being this last parameter most negatively affected during the five exposed generations, with a reduction of almost 50% in the last generation. These results emphasize the importance of multigenerational approaches, highlighting their advantage in the assessment of environmental contaminants.

Comparison of the Sensitivity of Tetragonisca angustula (Apidae-Meliponini) and Apis mellifera (Apidae-Apini) to Three Insecticides (Malathion, Imidacloprid, and Fipronil) Used in Costa Rica

The decline of insect pollinators is a significant concern within the current biodiversity crisis. The paradox between the benefits that these animals represent to humans and the evidence of human activities driving their extinction calls for the urgent protection of bees. To address the role of chemical pollution in this scenario, we assessed the acute toxicity as well as four biomarker responses (cholinesterase [ChE], glutathione S-transferase, catalase, and lipid peroxidation [LPO]) elicited by dietary 24-h exposure to three insecticides (malathion, imidacloprid, and fipronil) on the stingless neotropical bee Tetragonisca angustula and the honeybee Apis mellifera. Malathion was the most toxic substance to both species, with 48-h median lethal doses (LD50s) of 0.25 ng/bee to A. mellifera and 0.02 ng/bee to T. angustula. Fipronil was also highly toxic and presented a similar toxicity to both species, with 48-h LD50s of 0.5 ng/bee (A. mellifera) and 0.4 ng/bee (T. angustula). Imidacloprid had the lowest acute toxicity with a 48-h LD50 of 29 ng/bee for A. mellifera, whereas T. angustula tolerated exposure higher than 35 ng/bee. Apparent biomarker responses were observed in bees of both species that survived exposure to higher concentrations of malathion (ChE inhibition) and fipronil (increased LPO). Our results suggest that specific sensitivity to insecticides varies greatly among compounds and pollinator species, but the use of different representative species can facilitate the prioritization of substances regarding their risk to pollinators. Further research is necessary to better characterize the risk that pesticides represent in neotropical agricultural landscapes. Environ Toxicol Chem 2023;42:1022-1031. © 2023 SETAC.

Oxidative damage in the Vesper mouse (Calomys laucha) exposed to a simulated oil spill-a multi-organ study

Small wild mammals have been used to measure the damage caused by exposure to oil-contaminated soil, including deer mice. However, the study of toxic effects of crude oil using oxidative damage biomarkers in the wild rodent Calomys laucha (Vesper mouse) is absent. This investigation aimed to evaluate the effects of acute exposure to contaminated soil with different concentrations of crude oil (0, 1, 2, 4 and 8% w/w), simulating an accidental spill, using oxidative stress biomarkers in the liver, kidneys, lungs, testes, paw muscle, and lymphocytes of C. laucha. Animals exposed to the contaminated soil showed increases in lipid peroxidation and protein carbonylation at the highest exposure concentrations in most organ homogenates analyzed and also in blood cells, but responses to total antioxidant capacity were tissue-dependent. These results showed that acute exposure to oil-contaminated soil caused oxidative damage in C. laucha and indicate these small mammals may be susceptible to suffer the impacts of such contamination in its occurrence region, threatening the species' survival.

Oxidative Stress in a Wild Population of the Freshwater Fish Hyphessobrycon Luetkenii Chronically Exposed to a Copper Mining Area: New Insights into Copper Toxicology

In this study, we examine markers of oxidative stress in the tetra Hyphessobrycon luetkenii collected from two locations in the copper contaminated João Dias creek (southern Brazil). Also, specimens were translocated from a clean reference section of the creek to a polluted stretch and vice-versa. Fish were held at in submerged cages for 96 h and then sacrificed. Nuclear abnormalities in erythrocytes and total antioxidant capacity, lipid peroxidation and protein carbonylation in gills, brain, liver and muscle displayed similar trends in both groups. Lipid peroxidation increased in all tissues of individuals translocated to the polluted site but only in liver and muscle of those translocated to the reference site. Increased protein carbonylation was also observed in gills of individuals translocated to the reference location. These results suggest similar oxidative stress among fish from the reference and polluted locations and that long-term metals exposure may require adaptations toward oxidative stress responses.

The protective effects of baicalin and chrysin against emamectin benzoate-induced toxicity in Wistar albino rats

The aim of this study was to investigate the effects of baicalin, chrysin and their combinations against emamectin benzoate-induced toxicity in rats. For this purpose, sixty four rats were divided into evenly 8 groups with 6-8-week-old male Wistar albino rats, weighing 180-250 g, in each group. While the first group was kept as a control (corn oil), the remaining 7 groups were administered with emamectin benzoate (10 mg/kg bw), baicalin (50 mg/kg bw) and chrysin (50 mg/kg bw) alone or together for 28 days. Oxidative stress parameters, serum biochemical parameters and blood/tissue (liver, kidney, brain, testis and heart) and tissue histopathology were investigated. Compared to the control group, the emamectin benzoate-intoxicated rats had significantly higher tissue/plasma concentrations of nitric oxide (NO) and malondialdehyde (MDA), as well as lower tissue glutathione (GSH) concentrations and antioxidant enzyme activity (glutathione peroxidase/GSH-Px, glutathione reductase/GR, glutathione-S-transferase/GST, superoxide dismutase/SOD, catalase/CAT). Biochemical analysis showed that emamectin benzoate administration significantly increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities, as well as triglyceride, cholesterol, creatinine, uric acid and urea levels, and decreased serum total protein and albumin levels. The histopathological examination of the liver, kidney, brain, heart and testis tissues of the emamectin benzoate-intoxicated rats demonstrated necrotic changes. Baicalin and/or chrysin reversed the biochemical and histopathological alterations induced by emamectin benzoate on these tested organs. Therefore, baicalin and chrysin (alone or in combination) could offer protection against emamectin benzoate-induced toxicity.

Species-Specific Response of Corals to Imbalanced Ratios of Inorganic Nutrients

Dissolved inorganic phosphorus (DIP) is a limiting nutrient in the physiology of scleractinian corals. Anthropogenic addition of dissolved inorganic nitrogen (DIN) to coastal reefs increases the seawater DIN:DIP ratio and further increases P limitation, which is detrimental to coral health. The effects of imbalanced DIN:DIP ratios on coral physiology require further investigation in coral species other than the most studied branching corals. Here we investigated the nutrient uptake rates, elemental tissue composition and physiology of a foliose stony coral, Turbinaria reniformis, and a soft coral, Sarcophyton glaucum, exposed to four different DIN: DIP ratios (0.5:0.2, 0.5:1, 3:0.2, 3:1). The results show that T. reniformis had high uptake rates of DIN and DIP, proportional to the seawater nutrient concentrations. DIN enrichment alone led to an increase in tissue N content, shifting the tissue N:P ratio towards P limitation. However, S. glaucum had 5 times lower uptake rates and only took up DIN when the seawater was simultaneously enriched with DIP. This double uptake of N and P did not alter tissue stoichiometry. This study allows us to better understand the susceptibility of corals to changes in the DIN:DIP ratio and predict how coral species will respond under eutrophic conditions in the reef.

Biotransformation and oxidative stress responses in fish (Astyanax aeneus) inhabiting a Caribbean estuary contaminated with pesticide residues from agricultural runoff

The estuarine ecosystem of Madre de Dios Lagoon (MDL), in the Caribbean Coast of Costa Rica, is exposed to contamination with pesticide residues coming from the upstream agricultural areas. Biomarkers can provide a better indication of the fitness of biota in real mixture exposure scenarios than traditional lethal dose toxicity measurements. Here, we measured biomarkers of biotransformation, oxidative stress, and neurotoxicity on Astyanax aeneus, an abundant fish species in MDL. Glutathione S-transferase activity (GST), catalase activity (CAT), lipid peroxidation (LPO), and cholinesterase activity (ChE) were measured in fish collected during seven sampling campaigns, carried out between 2016 and 2018. Pesticide residues were analyzed in surface water samples collected every time fish were sampled. Residues of 25 pesticides, including fungicides, insecticides, and herbicides, were detected. The biomarkers measured in A. aeneus varied along the sampling moments, with biotransformation and oxidative stress signals showing a coupled response throughout the assessment. Furthermore, significant correlations were established between three biomarkers (GST, LPO, and CAT) and individual pesticides, as well as between GST and LPO with groups of pesticides with shared biocide action. Among pesticides, insecticide residues had a major influence on the responses observed in fish. This work demonstrates the chronic exposure to pesticide residues in MDL and how such exposure is related to physiological responses in fish that can affect their health and potentially, the trophic networks. This early warning information should be considered to improve the protection of estuarine ecosystems in the tropics.

Antiscalants used in the desalination industry impact the physiology of the coral Montipora capricornis

Many coral reefs are found in arid and semi-arid regions that often face severe water scarcity and depend on seawater desalination for freshwater supply. Alongside freshwater production, desalination plants discharge brine waste into the sea. Brine includes various chemicals (e.g., antiscalants) that may harm the coastal environment. Although widely used, little is known about the ecotoxicological effects of antiscalants (AS) on hard corals. This study compared the impacts of polyphosphonate-based and polymer-based ASs on the coral Montipora capricornis. After two weeks of exposure, we determined the effects of AS on coral physiology, symbiotic microalgae, and associated bacteria, using various analytical approaches such as optical coherence tomography, pulse amplitude modulated fluorometry, and oxidative stress biomarkers. Both ASs reduced polyp activity (∼25%) and caused tissue damage (30% and 41% for polymer and polyphosphonate based AS, respectively). In addition, exposure to polyphosphonate-based AS decreased the abundance of endosymbiotic algae (39%) and upregulated the antioxidant capacity of the animal host (45%). The microalgal symbionts were under oxidative stress, with increased levels of antioxidant capacity and oxidative damage (a 2-fold increase compared to the control). Interestingly, exposure to AS enhanced the numbers of associated bacteria (∼40% compared to the control seawater) regardless of the AS type. Our results introduce new insights into the effects of brine on the physiology of hard corals, highlighting that choosing AS type must be examined according to the receiving ecosystem.

Silver nano/microparticle toxicity in the shrimp Litopenaeus vannamei (Boone, 1931)

The effects of silver nano/microparticles (AgP) on juvenile Litopenaeus vannamei shrimp were evaluated through several responses, aiming to use it as a prophylactic and therapeutic method. Shrimps (3.19 ± 0.13 g) were exposed to clear water for 3 h with increasing concentrations of nanosilver (0; 25; 100; and 400 μg/l). After 3 h of exposure, they were transferred to water without nanosilver for 30 days (recovery). The weight gain and weekly growth were not affected by AgNP. Total antioxidant capacity (ACAP) increased in the hepatopancreas (exposure period) and gills (recovery) in shrimp exposed to AgNP. In muscle, ACAP was induced in shrimp exposed to 100 μg/l AgNP (exposure). In the gills, there was an increase in TBARS in shrimp exposed to 100 μg/l AgNP (recovery). In the concentration of protein-associated sulfhydryl groups (P-SH), a decrease was observed in the hepatopancreas (recovery) in the 100 μg/l AgNP treatment. In chromaticity parameters, an increase in reddish tones was observed in shrimp exposed to 100 μg/l AgNP (recovery). An increase in granular hemocytes was verified in shrimp exposed to 25 and 400 μg/l AgNP during exposure. Tissues analyzed histologically showed normal patterns without apoptosis or necrosis processes, and after 30 d of recovery, only in one muscle sample of shrimp exposed to μg/l of AgNP was silver detected. It is concluded that a prophylactic action of short duration (3 h) mostly did not affected the welfare of shrimp L. vannamei and can be considered its use as a therapeutic strategy.

Effects of Thermal Stress on the Antioxidant Capacity, Blood Biochemistry, Intestinal Microbiota and Metabolomic Responses of Luciobarbus capito

The rise in water temperature caused by global warming is seriously threatening the development of aquatic animals. However, the physiological response mechanism behind the adverse effects of thermal conditions on L. capito remains unclear. In this study, we investigated the physiological responses of L. capito exposed to thermal stress via biochemical analyses and intestinal microbiota and liver LC-MS metabolomics. The results show that the superoxide dismutase (SOD) and catalase (CAT) activities significantly decrease, while the malondialdehyde (MDA) content, aspartate aminotransferase (AST), acid phosphatase (ACP), alanine aminotransferase (ALT), and albumin (ALB) activities, and glucose (Glu) level significantly increase. Obvious variations in the intestinal microbiota were observed after stress exposure, with increased levels of Proteobacteria and Bacteroidota and decreased levels of Firmicutes, Fusobacteriota, and Actinobacteriota, while levels of several genera of pathogenic bacteria increased. Liver metabolomic analysis showed that stress exposure disturbed metabolic processes, especially of amino acids and lipids. The results of this study indicated that thermal stress caused oxidative stress, disturbed blood biological functioning and intestinal microbiota balance, and damaged amino acids and lipids metabolism of liver in L. capito.

Distribution of metals in different environmental compartments and oxidative stress biomarkers in Bryconops caudomaculatus (Osteichthyes: Characiformes) from a bauxite mining area in the Eastern Amazon

The Eastern Amazon is rich in bauxite ore. The extraction and processing of bauxite lead to the mobilization of Aluminum (Al) and other metals in environmental. We evaluated the metals (Al, Mn, Ba, and Cr) concentration in tissue, water, and sediment associated with antioxidant and oxidative damage responses in Bryconops caudomaculatus. The samplings were done in two hydrological periods (post-rain and post-dry periods) and at three points, located at two rivers: one in the surroundings of the mining area (P1) and other inside the mining area, upstream (P2), and downstream (P3). Defense antioxidant system biomarkers analyzed were total antioxidant capacity (ACAP) and glutathione-S-transferase (GST) activity. As an oxidative damage biomarker, the lipoperoxidation (LPO) was evaluated. Metals concentrations in the water and sediment were higher in the post-rain period compared to post-dry period. The water samples were acidic, with dissolved Al concentrations above the values established by local legislation at all points. In the gills, the metals accumulation was higher in fish from in the surrounding and upstream sites, and in the liver, was higher in fish from downstream site. Fish from the surrounding had increased antioxidant defenses, with higher ACAP in all tissues and higher GST in the gills. Consequently, they had lower levels of LPO. Fish from the mining area had decreased antioxidant defenses, with lower ACAP in all tissues and lower GST in the gills. Consequently, they had higher levels of LPO, indicating oxidative stress. The fish muscle was not responsive to GST and LPO at all sites. We conclude that the oxidative stress observed in the gills and liver of B. caudomaculatus from the area modified by the mining activity reflected the local anthropogenic impact status.

Arsenite and arsenate toxicity in the earthworm Eisenia andrei (Bouché 1972) in natural soil and tropical artificial soil

Inorganic forms of As (arsenite - As(III) and arsenate - As(V)) are prevalent in soil and recognized for their high toxicity. Once in the soil, these forms of As can compromise key organisms for ecological processes, such as earthworms. The aim of the study was to evaluate the toxicity of arsenite and arsenate in the Californian earthworm Eisenia andrei exposed in natural soil and tropical artificial soil (TAS). Adverse effects were evaluated using avoidance test, acute toxicity test, and a sublethal concentration test to assess biochemical parameters. LC50 values for arsenite were 21.27 mg/kg in natural soil and 19.0 mg/kg in TAS and for arsenate were 76.18 mg/kg in natural soil and above 120 mg/kg in TAS. In the avoidance test, this behavior was shown to be significantly higher in the natural soil and for earthworms exposed to arsenite, while total antioxidant capacity, glutathione levels, lipid damage, and DNA damage were significantly higher in animals exposed to arsenite, but without differences in relation to the two types of soil tested. Animals exposed to As(V) showed increased activity of enzymes related to glutathione metabolism. The results obtained in the present study show the impact of As exposure on the health of the Californian earthworm E. andrei, especially in the form of arsenite, and alert the public authorities that legal limits should, whenever possible, consider the soil properties and also the different chemical species of the contaminants.

Toxicity of Nanoscaled Zero-Valent Iron Particles on Tilapia, Oreochromis mossambicus

This research effort aims to evaluate the hazardous potential of the redox state (OH^-) of zero-valent iron nanoparticles (nZVI) and its histopathological and oxidative stress toward Mozambique tilapia, Oreochromis mossambicus. X-ray powder diffraction (XRD) validated the nZVI nanoparticles' chemical composition, while transmission electron microscopy (TEM) revealed that their physical form is round and oval. The exposure to 10 g/mL of nZVI induced the activation of the cellular superoxide dismutase (SOD) activity. Dose-dependent testing of O. mossambicus had a reduction in SOD and an increase in malondialdehyde (MDA) levels, suggesting that nZVI caused oxidative damage. At a concentration of 100 g/mL, the catalase (CAT) and peroxidase (POD) activities of diverse tissues exhibited a gradual decrease after 2 days of exposure and a fast increase until day 6. The scavenging of reactive oxygen species (ROS) in the epidermis, liver, and gills of O. mossambicus deteriorated and accumulated gradually. MDA levels in the skin, gill, and liver tissues were substantially higher after 8 days of exposure to 100 and 200 g/mL nZVI compared to those of the control group and those exposed to 10 and 50 g/mL nZVI for 2 days. Extreme histological and morphological abnormalities were seen in the skin, gill, and liver tissues of experimental animals, demonstrating that the damage resulted from direct contact with nZVI in water. A one-way ANOVA followed by Dunnett's post-test was performed to investigate significant differences.

Effect of Hydrogel Containing Achyrocline satureioides (Asteraceae) Extract-Loaded Nanoemulsions on Wound Healing Activity

Achyrocline satureioides (Lam.) DC extract-loaded nanoemulsions have demonstrated potential for wound healing, with promising effects on keratinocyte proliferation. We carried out the first in vivo investigation of the wound healing activity of a hydrogel containing A. satureioides extract-loaded nanoemulsions. We prepared hydrogels by adding the gelling agent (Carbopol^® Ultrez) to extract-loaded nanoemulsions (~250 nm in diameter) obtained by spontaneous emulsification. The final flavonoid content in formulation was close to 1 mg/mL, as estimated by ultra-fast liquid chromatography. Permeation/retention studies using porcine ear skin showed that flavonoids reached deeper layers of pig ear skin when it was damaged (up to 3.2 µg/cm² in the dermis), but did not reach the Franz-type diffusion cell receptor fluid. For healing activity, we performed a dorsal wound model using Wistar rats, evaluating the lesion size, anti-inflammatory markers, oxidative damage, and histology. We found that extract-loaded formulations promoted wound healing by increasing angiogenesis by ~20%, reducing inflammation (tumor necrosis factor α) by ~35%, decreasing lipid damage, and improving the re-epithelialization process in lesions. In addition, there was an increase in the number of blood vessels and hair follicles for wounds treated with the formulation compared with the controls. Our findings indicate that the proposed formulation could be promising in the search for better quality healing and tissue reconstruction.

Chronic Effects of Carbamazepine, Progesterone and Their Mixtures at Environmentally Relevant Concentrations on Biochemical Markers of Zebrafish (Danio rerio)

The impact of pharmaceuticals on non-target organisms in the environment is of increasing concern and study. Pharmaceuticals and other pollutants are often present as mixtures in an environmental compartment. Studies on the toxicological implications of these drugs on fish, particularly as mixtures at environmentally relevant concentrations, are very limited. Thus, this study aimed to evaluate the chronic effects of the anticonvulsant drug carbamazepine (CBZ) and progesterone (P4) at environmentally relevant concentrations, individually and in binary mixtures, applying a suite of biomarkers at the molecular level in zebrafish (Danio rerio). The effects on biotransformation enzymes 7-ethoxyresorufin O-deethylase (EROD) and glutathione-S-transferase (GST), antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidases (GPxSe and GPxTOT), and glutathione reductase (GR), and markers of damage, such as DNA strand breaks (DNAsb), lactate dehydrogenase (LDH), lipid peroxidation (LPO), and vitellogenin-like proteins (VTG), were evaluated. Analyses of the biochemical markers indicated that a synergistic dose-ratio-dependent effect of CBZ and P4 in zebrafish occurs after chronic exposure regarding VTG, biotransformation enzymes (EROD, GST), and oxidative stress marker (DNAsb). The results suggest a synergistic effect regarding VTG, thus indicating a high risk to the reproductive success of fish if these pharmaceuticals co-occur.

Effects of the insecticide β-endosulfan on tadpoles of Isthmohyla pseudopuma (Anura: Hylidae)

Conventional agriculture uses pesticides intensively. Once pesticides are released into the environment, they can be toxic to non-target organisms. Exposure of amphibians to pesticides can be lethal and affect their growth, development and behavior. β-endosulfan is a persistent organochlorine that has been detected in environmental samples within protected sites in Costa Rica, far from agricultural areas. The aim of this study was to evaluate the lethal and sublethal effects, as well as changes in three biomarkers (Cholinesterase activity [ChE], glutathione S-transferase activity [GST] and lipid peroxidation [LPO]) in tadpoles of Isthmohyla pseudopuma exposed to β-endosulfan. A 96-h acute test (20, 40, 60, 80, 100 and 200 µg/L) was performed in order to calculate the median lethal concentration (LC₅₀), while effects on growth and development were assessed during a 4-weeks chronic test (10, 20, 30 and 50 µg/L). In addition, we measured the aforementioned biomarkers in tadpoles exposed to concentrations below the LC₅₀. The 96-h LC₅₀ for this species was 123.6 µg/L. We found no evidence of β-endosulfan influencing any of the three biomarkers evaluated. At 50 µg/L, both length and total weight of tadpoles decreased with respect to the control. Also, at 30 and 50 µg/L we observed that individuals showed a slower development. Therefore, we demonstrated that at sublethal concentrations, β-endosulfan negatively affects I. pseudopuma at early stages causing tadpoles to develop slower and smaller than normal.

Effect of biological and anthropogenic habitat sounds on oxidative stress biomarkers and behavior in a key crab species

Soundscapes are characterized by a combination of natural and anthropogenic sounds. This study evaluated the stress effect of biological and anthropogenic sounds characterizing a Man and Biosphere UNESCO wetland, by assessing the protein content, oxidative biomarkers, and behavior of a key crab species (Neohelice granulata), through a tank-laboratory experiment. Biological sounds corresponded to predators of N. granulata (fish and crustacean stimuli), while anthropogenic ones belonged to motorboat passages (boat stimulus). Biochemical results showed differences depending on the sound stimuli used and the crab tissue analyzed. Protein content was higher in hemolymph when crabs were exposed to fish and boat stimuli, and in gills when exposed to boat stimulus. The enzymatic activity in hemolymph showed a decreased GST (fish stimulus) and CAT (fish and boat stimuli) activity, in hepatopancreas a higher GST (crustacean stimulus) and CAT (crustacean and boat stimuli) activity was found, and in gills a higher CAT activity was also observed (crustacean and boat stimuli). Lipid peroxidation was higher only in hemolymph (fish and crustacean stimuli). Protein oxidation was higher in gills (fish stimulus) and hepatopancreas (crustacean stimulus). Behavioral analysis demonstrated that the crab locomotion activity diminished when exposed to diverse sound stimuli. Thus, both sound sources caused physiological and behavioral stress in this species. The results contribute important data to be used in the development of management plans considering the habitat importance in terms of biodiversity, the ecosystem services provided and the role of the studied species.

Biochemical Marker Assessment of Chronic Carbamazepine Exposure at Environmentally Relevant Concentrations in Juvenile Common Carp (Cyprinus carpio)

Worldwide, the anticonvulsant drug carbamazepine (CBZ) is the most frequently identified pharmaceutical residue detected in rivers. Reported chronic effects of CBZ in non-target freshwater organisms, particularly fish, include oxidative stress and damage to liver tissues. Studies on CBZ effects in fish are mostly limited to zebrafish and rainbow trout studies. Furthermore, there are only a few chronic CBZ studies using near environmental concentrations. In this study, we provide data on subacute effects of CBZ exposure (28 days) to common carp (Cyprinus carpio), employing a set of biochemical markers of damage and exposure. CBZ was found to induce a significant change in the hepatic antioxidant status of fish subjected to 5 µg/L. Moreover, with increasing concentrations, enzymatic and non-enzymatic biomarkers of oxidative defence (catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), DNA strand breaks)), toxicant biotransformation (ethoxyresorufin-o-demethylase (EROD), glutathione-S-transferase (GST)), and organ and tissue damage (lactate dehydrogenase (LDH), cetylcholinesterase (AChE)) were altered. The AChE, LDH, and lipid peroxidation (LPO) results indicate the occurrence of apoptotic process activation and tissue damage after 28 days of exposure to CBZ. These findings suggest significant adverse effects of CBZ exposure to common carp at concentrations often found in surface waters.

Acute exposure to perfluorooctane sulfonate exacerbates heat-induced oxidative stress in a tropical coral species

Perfluorooctane sulfonate (PFOS) is among the most commonly per- and poly-fluoroalkyl substances (PFAS) found in environmental samples. Nevertheless, the effect of this legacy persistent organic contaminant has never been investigated on corals to date. Corals are the keystone organisms of coral reef ecosystems and sensitive to rising ocean temperatures, but it is not understood how the combination of elevated temperature and PFOS exposure will affect them. Therefore, the aims of the present study were (1) to evaluate the time-dependent bioconcentration and depuration of PFOS in the scleractinian coral Stylophora pistillata using a range of PFOS exposure concentrations, and (2) to assess the individual and combined effects of PFOS exposure and elevated seawater temperature on key physiological parameters of the corals. Our results show that the coral S. pistillata rapidly bioconcentrates PFOS from the seawater and eliminates it 14 days after ceasing the exposure. We also observed an antagonistic effect between elevated temperature and PFOS exposure. Indeed, a significantly reduced PFOS bioconcentration was observed at high temperature, likely due to a loss of symbionts and a higher removal of mucus compared to ambient temperature. Finally, concentrations of PFOS consistent with ranges observed in surface waters were non-lethal to corals, in the absence of other stressors. However, PFOS increased lipid peroxidation in coral tissue, which is an indicator of oxidative stress and enhanced the thermal stress-induced impairment of coral physiology. This study provides valuable insights into the combined effects of PFOS exposure and ocean warming for coral's physiology. PFOS is usually the most prevalent but not the only PFAS defected in reef waters, and thus it will be also important to monitor PFAS mixture concentrations in the oceans and to study their combined effects on aquatic wildlife.

Dietary nanoselenium supplementation for heat-stressed rainbow trout: effects on organizational structure, lipid changes, and biochemical parameters as well as heat-shock-protein- and selenoprotein-related gene expression

Nanoselenium (nano-Se) shows unique protective effects against environmental heat stress in rainbow trout as a selenium source additive and free radical scavenger. Accordingly, we investigated the effects of supplementation with different levels of nano-Se (0, 5, and 10 mg/kg) and before and after heat stress (24°C) for different treatment times on the dynamic changes of rainbow trout liver tissue structure, lipid changes, biochemical properties, and gene expression. The results showed that, under heat stress, the fish supplementation of 5 mg/kg nano-Se significantly increased liver glutathione peroxidase (GPx) activity and upregulated expression levels of HSP70b, HSP90a1, GPx1a, and Trx mRNAs, while liver alanine aminotransferase (ALT), aspartate aminotransferase (AST), superoxide dismutase (SOD), and malondialdehyde (MDA) levels as well as tissue structure damage and lipid accumulation were decreased. Combining the trends for the above indicators indicated that stress began to increase significantly at 8 h. It can be concluded that supplementation with 5 mg/kg nano-Se effectively alleviates stress damage in rainbow trout. Furthermore, stress at 24°C for 8 h can be thought of as a critical time point for the study of heat stress in rainbow trout, with significant changes in response but no serious damage. Thus, these results provide a reference for the addition of nano-Se to rainbow trout feed and provide theoretical and practical guidance for enhancing the resistance of rainbow trout to heat stress.

Oxidative stress responses after exposure to triclosan sublethal concentrations: an integrated biomarker approach with a native (Corydoras paleatus) and a model fish species (Danio rerio)

Triclosan (TCS) is a synthetic broad-spectrum antimicrobial agent commonly used world-wide in a range of personal care and sanitizing products detected frequently in aquatic ecosystems. The aim of this study was to examine biochemical markers responses triggered by TCS in Danio rerio and in a native South American fish species (Corydoras paleatus). Further, an integrated approach comparing both test fish species was undertaken. These fish organisms were exposed to 100 or 189 µg TCS/L for 48 h. The activities of catalase (CAT), glutathione-s-transferase (GST), superoxide dismutase (SOD), and lipid peroxidation levels (LPO) and total antioxidant capacity against peroxyl radicals (ACAP) were determined in liver, gills, and brain. Acetylcholinesterase activity (AChE) was measured in the brain. Multivariate analysis showed that the most sensitive hepatic parameters were activities of GST and SOD for C. paleatus while LPO levels were for D. rerio. In gills the same parameters were responsive for C. paleatus but CAT in D. rerio. ACAP and GST activity were responsive parameters in brain of both species. Integrated biomarker responses (IBR) index demonstrated similar trends in both species suggesting this parameter might serve as a useful tool for quantification of integrated responses induced by TCS.

Polystyrene nanoplastics impair the photosynthetic capacities of Symbiodiniaceae and promote coral bleaching

Reef-building corals are increasingly threatened by global and regional stresses, which affect the stability of the coral-Symbiodiniaceae association. Among them, plastic pollution has been an ongoing and growing concern. Whereas several studies have highlighted the detrimental impact of microplastics (0.1 μm-5 mm) on corals and their symbiotic dinoflagellate algae, the physiological changes induced by nanoplastic (NP, <0.1 μm) pollution are still poorly known. Long-term experiments (4 weeks) were conducted to investigate the effects of ecologically relevant NP concentrations (0 to 0.5 mg/L of 20 nm polystyrene NPs) on two Symbiodiniaceae in culture [CCMP2467 or Clade A1 and pd44b or Clade F1]. The effects of 0.5 mg/L NPs were also evaluated on Clade A1 living in symbiosis with the coral Stylophora pistillata, to assess the in hospite effects of NPs on coral symbionts. The photosynthetic efficiency of photosystem II, the oxidative status of the Symbiodiniaceae and the coral host, as well as the host-symbiont stability were evaluated at the end of the experiment. Symbiodiniaceae in culture exhibited a significant decrease in the maximal electron transport rate (ETR_max) at NP concentrations as low as 0.005 mg/L, highlighting an impairment of the photosynthetic capacities of the dinoflagellates in presence of nanoplastics. Also, Clade A1 exhibited a significant decrease in its Total Antioxidant Capacity (TAC) and an increase in Lipid Peroxidation (LPO), which evidence oxidative stress and cellular damage. Interestingly, Clade A1 in hospite did not show any signs of oxidative stress, however, the coral host exhibited increased TAC and LPO. Additionally, exposure of S. pistillata to 0.5 mg/L NPs induced significant bleaching (loss of symbionts and photosynthetic pigments). Overall, NPs were detrimental for both the Symbiodiniaceae in culture and the host-symbiont association. In the future, the persistence of reef corals may be severely impacted by the cumulative effects of nanoplastic pollution along with global warming.

p-Menthadienols-rich essential oil from Cymbopogon martini ameliorates skin inflammation

Cymbopogon martini variety sofia, commonly known as ginger-grass, is an important aromatic crop used by the perfumery, medicinal and cosmetic industries worldwide. This study explores the chemical and possible pharmacological profile of hydro-distilled essential oil of C. martini variety sofia against skin inflammation. The essential oil extracted by the hydrodistillation process was analyzed by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR) to identify its constituents, and was coded as CMA-01 for further in vitro and in vivo pharmacological study related to skin inflammation. The chemical fingerprint revealed that CMA-01 oil has (E)-p-mentha-2,8-dien-1-ol (21.0%), (E)-p-mentha-1(7),8-dien-2-ol (18.1%), (Z)-p-mentha-1(7),8-dien-2-ol (17.4%), (Z)-p-mentha-2,8-dien-1-ol (9.0%), limonene (7.7%), and (E)-carveol (5.7%) as major components. The pre-treatment of CMA-01 showed significant inhibition of pro-inflammatory markers in activated HaCat cells without cytotoxic effect. The in vivo study revealed the ameliorative impact of CMA-01 against skin inflammation induced by TPA in mouse ears as evidenced by a reduction of ear edema, pro-inflammatory mediators (IL-6, TNF-α), oxidative stress markers (malondialdehyde and nitric-oxide) and histological changes in ear tissues without any skin irritation response on rabbit skin. These findings suggest the suitability of CMA-01 as a valuable therapeutic candidate for the treatment of skin inflammation.

Assessment of the effects of seasonality on the ecotoxicity induced by the particulate matter using the animal model Caenorhabditis elegans

The present work aimed to establish potential changes in the ecotoxicological effects on C. elegans induced by the exposure of coarse (PM₁₀) and fine (PM_2.5) particulate matter collected during dry and rainy periods. We also analyzed the probable influence on the change of a city's activities as the mega-events result in air quality. The element levels evaluation was performed on PM, on the solutions of exposure, and C. elegans after exposure. Biochemical essays were performed to evaluate damage to C. elegans. The results showed that infrastructure works increased the levels of pollutants, generating increases in the concentrations of PM_2.5 and PM₁₀. The biochemical results suggested effects mediated by different mechanisms, where PM_2.5 induced an increase in antioxidant capacity with activation of the defense system and lipoperoxidation. Results suggest that PM₁₀ reduces the antioxidant capacity and activates the glutathione S-transferase activity enzymatic action, but also induces lipoperoxidation in all groups of animals exposed to samples collected during the dry period of 2016. Individuals exposed to PM_2.5 in 2017 wet and dry periods and PM₁₀ in 2016 and 2017 dry periods shown a decrease in size compared to controls, while for fertility data, there was a decrease only in individuals exposed to PM_2.5 in the periods that the highest levels of PM concentration. We conclude that despite the positive issues linked to the hosting of mega-events, their infrastructure requirements can compromise air quality and bring damage related to lipoperoxidation and physiological changes in the life cycle of biological systems, such as what happened to C. elegans exposed to tested extracts. Also, rainy events reduced the presence of these pollutants, washing the atmosphere.

Biochemical response and metals bioaccumulation in planktonic communities from marine areas impacted by the Fundão mine dam rupture (southeast Brazil)

The rupture of the Fundão dam (Mariana, MG, southeast Brazil) released a huge flood of mine tailings to Doce river basin and its adjacent coastal area, in November 2015. This catastrophic event exposed aquatic communities to metal contamination related to mine tailings, but its biological effects are still poorly understood. This study investigates how biochemical response related to metal exposure vary between locations and seasons during the years of 2018-2020, in planktonic communities (micro and mesoplankton). Marine microplankton collected in sectors in front and south of the Doce river mouth presented the highest lipid peroxidation (LPO) and induction of metallothioneins (MT). Mesoplankton collected in sectors in front and north of the Doce river mouth presented highest LPO, while MT in this size class did not respond to a clear spatial pattern. Our results showed that metals affected biomarkers in a non-linear pattern and highlighted the complex relationship between metals, biochemical parameters, and seasonality. The variation in biochemical biomarkers indicates physiological stress related to metals, once sectors contaminated by metals, especially Fe, Mn and Cd, presented stronger biochemical responses. Comparison of metal levels with bioaccumulation data collected before the impact indicates Fe, Cd, Cr and Cu more than 2-fold higher after disaster in sectors closer to the river. Literature showed that these sectors present zooplanktonic assemblages with lower biomass and biodiversity, suggesting that the opportunistic species that thrives in the area are also under biochemical stress, but possibly relies on repair or defense mechanisms. The physiological stress detected by this study is possibly related to the mine tailings, considering the metals that stood out and the proximity with the Doce river mouth. This suggests that the impacts related to the failure of Fundão dam are still affecting the marine planktonic community even three to four years after the environmental disaster.

Response of biomarkers to metals, hydrocarbons and organochlorine pesticides contamination in crabs (Callinectes ornatus and C. bocourti) from two tropical estuaries (São José and São Marcos bays) of the Maranhão State (northeastern Brazil)

Response of biomarkers to chemical contamination was evaluated in crabs of the Callinectes genus (Callinectes ornatus and C. bocourti) from two tropical estuaries (São José and São Marcos bays) of the Maranhão State (northeastern Brazil). Biomarkers evaluated included hepatopancreatic metallothionein-like proteins (MTLP) and lipid peroxidation (LPO), as well as muscle acetylcholinesterase (AChE). Tissue concentrations of metals (pereiopod muscle and hepatopancreas), hydrocarbons (hepatopancreas) and organochlorine pesticides (hepatopancreas) were also evaluated. Crab samples were collected in three sites of each estuary (São Marcos Bay and São José Bay). Sampling was performed in August/2012 (dry season), January/2013 (rainy season), August/2013 (dry season), and January/2014 (rainy season). Concentrations of chemical contaminants and responses of biomarkers showed significant spatial (São Marcos Bay and São José Bay) and/or seasonal (dry and rainy seasons) and annual (2012-2014) variability. However, a general higher Zn concentration was observed in hepatopancreas of crabs from São José Bay. In turn, a general higher Cd concentration paralleled by oxidative damage (LPO) was observed in hepatopancreas of crabs from São Marcos Bay. As expected, these findings support the idea that this bay is more intensively or chronically impacted by industrial activities while the São José Bay is likely more affected by domestic activities. Interestingly, LPO level in crab hepatopancreas showed to be the most reliable and adequate biomarker to distinguish the two bays.

Toxicity impact of hydrogen peroxide on the fate of zebrafish and antibiotic resistant bacteria

Hydrogen peroxide (H₂O₂) is applied in various environments. It could be present at concentrations ranging from nanomolar to micromolar in a water system. It is produced through pollutants and natural activities. Since few studies have been conducted about the impact of naturally produced H₂O₂ on aquatic organisms, the objective of the present study was to monitor changes in responses of aquatic model organisms such as zebrafish and antibiotic-resistant bacteria to different exogenous H₂O₂ exposure. Increases in exposure concentration and time induced decreases in the perception of zebrafish larvae (up to 69%) and movement of adult zebrafish (average speed, average acceleration, movement distance, and activity time) compared to the control (non-exposed group). In addition, as a function of H₂O₂ exposure concentration (0-100,000 nM) and time, up to 20-fold increase (p = 5.00*10^-6) of lipid peroxidation compared to control was observed. For microorganisms, biofilm, an indirect indicator of resistance to external stressors, was increased up to 68% and gene transfer was increased (p = 2.00*10^-6) by more than 30% after H₂O₂ exposure. These results imply that naturally generated H₂O₂ could adversely affect aquatic environment organisms and public health. Thus, more careful attention is needed for H₂O₂ production in an aquatic system.