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Arsenic (As) is a ubiquitous contaminant in the environment and it is known to induce oxidative stress in aquatic organisms. In an attempt to remove As from water, some studies have suggested the titanium dioxide nanomaterial (nTiO

Carbon nanomaterials (CNM), such as graphene oxide (GO), have been the focus of study in several areas of science mostly due to their physical-chemical properties. However, data concerning the potential toxic effects of these CNM in bivalves are still scarce. When present in the aquatic systems, the combination with other contaminants, as well as pH environmental variations, can influence the behavior of these nanomaterials and, consequently, their toxicity. Thus, the main goal of this study was to evaluate the effect of exposure of clam Ruditapes philippinarum to GO when acting alone and in the combination with copper (Cu), under two pH levels (control 7.8 and 7.3). A 28-day exposure was performed and metabolism and oxidative stress-related parameters were evaluated. The effects caused by GO and Cu exposures, either isolated or co-exposed, showed a direct and dependent relationship with the pH in which the organisms were exposed. In clams maintained at control pH (7.8), Cu and GO + Cu treatments showed lower lipid peroxidation (LPO) and lower electron transport system (ETS) activity, respectively. In clams maintained at low pH, glutathione-S-transferases (GSTs) activities were increased in Cu and Cu + GO treatments, whereas reduced glutathione (GSH) levels were increased in Cu treatment and ETS activity was higher in GO + Cu. Thus, it can be observed that clams responses to Cu and GO were strongly modulated by pH in terms of their defense system and energy production, although this does not result into higher LPO levels.

Made available in DSpace on 2019-10-04T11:57:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-04-01 Instituto Nacional de Ciencia e Tecnologia Nanomaterial de Carbono Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Given the increasing use of carbon nanotubes (CNT) in several industries and technological applications, it is essential to perform in vivo toxicological studies with these nanomaterials to evaluate their potential ecotoxicity. Dopamine (DA) and serotonin (5HT) are key neurotransmitters for brain functions and behavioral responses. Determination of DA and 5HT were performed in brain samples from zebrafish Danio rerio exposed i.p. to single-walled CNT (SWCNT), besides analyzing acetylcholinesterase (AChE) and ectonucleotidases activity, lipid peroxidation and total antioxidant capacity. Results showed that treatment with SWCNT increased between 3 and 6-fold the concentration of DA and 5HT (p < 0.05). Similarly, a significant reduction (p < 0.05) in AChE activity was observed in the brains of SWCNT exposed zebrafish when compared to the control groups. Cholinergic, serotonergic, and dopaminergic systems, through AChE activity and serotonin and dopamine levels, respectively were affected by SWCNT in the zebrafish brain. Alterations in these neurotransmitters can potentially affect several physiological and behavioral that they control. Univ Fed Rio Grande FURG, ICB, Av Italia Km 8 S-N,Cx P 474, BR-96200970 Rio Grande, RS, Brazil Univ Fed Rio Grande FURG, ICB, Progmma Posgrad Ciencias Fisiol FAC, Rio Grande, RS, Brazil Rede Nanotoxicol MCTI CNPq, Brasilia, DF, Brazil Inst Nacl Ciencia & Tecnol Nanomat Carbono CNPq, Belo Horizonte, MG, Brazil Fac Biociencias PUCRS INCT TM CNPq, Porto Alegre, RS, Brazil Univ Estadual Paulista, Sao Jose Do Rio Preto, SP, Brazil Univ Fed Rio Grande do Sul, Porto Alegre, RS, Brazil Univ Fed Minas Gerais, Belo Horizonte, MG, Brazil Univ Estadual Paulista, Sao Jose Do Rio Preto, SP, Brazil CNPq: 421701/2017-0

We present an in silico approach for modeling the noncovalent interactions between the human mitochondrial voltage-dependent anion channel (hVDAC1) and a family of single-walled carbon nanotubes (SWCNTs) with a defined pattern of topological vacancies ( v = 1-16), obtained by removing atoms from the SWCNT surface. The general results showed more stable docking interaction complexes (SWCNT-hVDAC1), with more negative Gibbs free energy of binding affinity values, and a strong dependence on the vacancy number ( R2 = 0.93) and vacancy formation energy ( R2 = 0.96). In addition, for most of the SWCNT vacancies that were analyzed, the interatomic distances for the interactions of the SWCNT-hVDAC1 complex with the functional catalytic residues (i.e., Pro7, Gln199, Gln182, Phe181, Val20, Asp19, Lys15, Gly14, Asp12, Ala11, and Arg18) that form the hVDAC1 active site (i.e., the voltage-sensing N-terminal α-helix segment) were very similar to or shorter than the interatomic distances of these residues for ATP-hVDAC1 interactions. In particular, the hVDAC1 residues that can be phosphorylated like Tyr10, Tyr198, and Se16 were significantly perturbed by the interactions with SWCNT with at least nine vacancies. In addition, the SWCNT vacancy family members can affect the flexibility properties of the hVDAC1 N-terminal α-helix segment inducing different patterns of local perturbations in inter-residue communication. Finally, vacancy quantitative structure-binding relationships (V-QSBRs) were unveiled for setting up a robust model that can predict the strength of docking interactions between SWCNTs with a specific topological vacancy and hVDAC1. The developed V-QSBR model classified properly all of the SWCNTs with a different number of SWCNT vacancies with exceptional sensitivity and specificity (both equal to 100%), indicating a strong potential to unequivocally predict the influence of SWCNT vacancies on the mitochondrial channel interactions.

Made available in DSpace on 2021-06-25T10:36:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-16 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Shrimp trawling is an important socio-economic activity; however, the bycatch can be problematic to the environment. Thus, the present study investigated potential uses of the bycatch to generate value-added products. The biological activity of the protein hydrolysates obtained from the two most abundant fish species (Micropogonias furnieri and Paralonchurus brasiliensis) was evaluated. Muscle and skin samples of both species were hydrolyzed using two enzymes, Alcalase 2.4 L® or Protamex®. The in vitro antioxidant capacity against peroxyl radicals, DPPH, and sulfhydryl groups were analyzed. Cell viability, Western Blotting, Zymogram, and Real-time PCR analyses were performed. The results showed that the hydrolysates have antioxidant activity and no effect on cell viability at doses lower than 16 mg/mL. In addition, they can modulate extracellular remodelling and intracellular pathways related to cell adhesion. Thus, the hydrolysis of the fish bycatch allows the release of bioactive peptides with potential use in the food industry. Aquaculture Center São Paulo State University (UNESP), Campus Jaboticabal Marine Station of Aquaculture Aquaculture postgraduate Oceanography Institute Federal University of Rio Grande (FURG) Rio Grande Institute of Biological Sciences (ICB) Federal University of Rio Grande (FURG) Department of Chemistry and Biochemistry Bioscience Institute São Paulo State University (UNESP), Campus Botucatu Aquaculture Center São Paulo State University (UNESP), Campus Jaboticabal Department of Chemistry and Biochemistry Bioscience Institute São Paulo State University (UNESP), Campus Botucatu

The aim of this study was to evaluate the anaesthetic activities of the extractives of Nectandra grandiflora and Spilanthes acmella in juvenile tambaqui fish, Colossoma macropomum as well as to investigate their effects on oxidative stress status of fish submitted to transport in hyperoxia. Fish were placed in aquaria containing five different concentrations of essential oil (EO) of N. grandiflora (25; 50; 100; 200; and 300 μL L − 1 ) or waxy extract of S. acmella (5; 10; 15; 20; and 25 mg L − 1 ), and the times of anaesthetic induction and recovery were determined by concentration-response trials. Fish transported inside plastic bags in hyperoxic conditions for 2, 6 and 10 h with or without anaesthetics were investigated for the occurrence of oxidative stress through the assessment of total antioxidant capacity against peroxyl radicals (ACAP), glutathione S-transferase (GST) activity and lipid peroxidation levels (TBARS) in muscle, gills, liver and brain. Both extractives of S. acmella and N. grandiflora induced deep anaesthesia in juvenile C. macropomum . Although transient changes occurred in ACAP and GST activity after transport, irrespective of transport time or anaesthetic used, antioxidant components in these extractives reduced or maintained lipid peroxidation within basal levels in the assessed organs. The use of 10 mg L − 1 of extract of S. acmella was suitable to induce fast anaesthesia ( − 1 and 30 μL L − 1 of the extractives of S. acmella and N. grandiflora respectively, enhanced protection against oxidative damage mainly in muscle and gills of juvenile tambaqui and therefore have the potential to be used as chemoprotectants for transport purposes. Statement of relevance This study presents novel products to be used as anaesthetics/sedatives for fish.

The production and use of graphene-based nanomaterials is rapidly increasing. However, few data are available regarding the toxicity of these nanomaterials in aquatic organisms. In the present study, the toxicity of few-layer graphene (FLG) (obtained by chemical exfoliation) was evaluated in different tissues of the shrimp Litopenaeus vannamei following exposure to FLG through a diet for four weeks. Transmission electron microscopy and dynamic light scattering measurements showed a distribution of lateral sheet sizes between 100 and 2000 nm with the average length and width of 800 and 400 nm, respectively. Oxidative stress parameters were analyzed, indicating that FLG exposure led to an increase in the concentration of reactive oxygen species, modulated the activity of antioxidant enzymes such as glutamate cysteine ligase and glutathione-S-transferase, and reduced glutathione levels and total antioxidant capacity. However, the observed modulations were not sufficient to avoid lipid and DNA damage in both gill and hepatopancreas tissues. Furthermore, graphene exposure resulted in morphological changes in hepatopancreas tissues. These results demonstrate that exposure to FLG through the diet induces alterations in the redox state of cells, leading to a subsequent oxidative stress situation. It is therefore clear that nanomaterials presenting these physico-chemical characteristics may be harmful to aquatic biota.

The intensity of exercise determines the metabolic pathway and the energetic substrate that is spent. Our study sought to identify the effects of different intensities of swimming on myocardial oxidative status and the blood lipid profile. Eighty Wistar rats (male and female) submitted to different intensities of a swimming regimen (low, LS; moderate, MS; or high, HS) for 16 weeks. Samples of blood and myocardium from the left ventricle were collected to determine lipid profiles and oxidative status. Reactive oxygen species (ROS) and antioxidant capacity against peroxyl radicals (ACAP), lipid profiles and lipid peroxidation was analyzed. ROS levels and ACAP were higher in male rats than in female rats overall (p

Saxitoxins (STXs) are potent neurotoxins that also induce cytotoxicity through the generation of reactive oxygen species. Carbon nanotubes (CNTs) are nanomaterials that can promote a Trojan horse effect, facilitating the entry of toxic molecules to cells when adsorbed to nanomaterials. The interaction of pristine single-walled (SW)CNTs and carboxylated (SWCNT-COOH) nanotubes with STX was evaluated by ab initio simulation and bioassays using the cell line HT-22. Cells (5 × 104 cells/mL) were exposed to SWCNT and SWCNT-COOH (5 μg mL−1), STX (200 μg L−1), SWCNT+STX, and SWCNT-COOH+STX for 30 min or 24 h. Results of ab initio simulation showed that the interaction between SWCNT and SWCNT-COOH with STX occurs in a physisorption. The interaction of SWCNT+STX induced a decrease in cell viability. Cell proliferation was not affected in any treatment after 30 min or 24 h of exposure (p > 0.05). Treatment with SWCNT-COOH induced high reactive oxygen species levels, an effect attenuated in SWCNT-COOH+STX treatment. In terms of cellular oxygen consumption, both CNTs when coexposed with STX antagonize the toxin effect. Based on these results, it can be concluded that the results obtained in vitro corroborate the semiempirical evidence found using density functional theory ab initio simulation. Environ Toxicol Chem 2017;36:1728–1737. © 2016 SETAC

Two microcosm types -sediment-biota and biota-biota- were constructed to simulate different pathways of BDE-47 uptake, metabolism and oxidative stress effects in two key estuarine invertebrates (polychaete Laeonereis acuta and crab Cyrtograpsus angulatus). In the sediment-biota experiment, both species were exposed to spiked sediments; an environmentally reported and a high concentration of BDE-47 for 2 weeks. In the biota-biota experiment, crabs were fed with polychaetes pre-exposed to BDE-47 in the sediment-biota experiment. The sediment-biota experiment first revealed that polychaetes significantly accumulated BDE-47 (biota-sediment accumulation factor >2; p < 0.05) to a much greater extent than the crab organs (muscle, hepatopancreas, gills) at both sediment concentrations. For oxidative stress responses, polychaete and crab tissues exposed to spiked sediment showed a significant increase (p < 0.05) of only glutathione S-transferase (GST) activity with respect to controls in both BDE-47 concentrations. No lipid peroxidation (TBARS) or total antioxidant capacity (ACAP) changes were evident in the species or organs exposed to either BDE-47 sediment concentration. The biota-biota experiment showed that feeding crabs with pre-exposed polychaetes caused BDE-47 accumulation in organs as well as significant amounts of BDE-47 eliminated through feces (p < 0.05). Unlike the sediment-biota exposure, crabs fed with pre-exposed BDE-47 polychaetes showed the most conspicuous oxidative stress responses. Significant changes in GST and ACAP in both hepatopancreas and gills, in addition to enhanced TBARS levels in the hepatopancreas with respect to controls (p < 0.05), revealed that BDE-47 assimilated by invertebrates represents a potential source of toxicity to their predators. No methoxylated metabolites (MeO-PBDEs) were detected during BDE-47 metabolism in the invertebrates in either of the two different exposure types. In contrast, hydroxylated metabolites (OH-PBDEs) were detected in polychaetes and crab organs/feces in both experiments. Our results demonstrate that PBDE hydroxylation is one of the main biotransformation routes of BDE-47 in estuarine animals, which could be associated with the oxidative stress responses found. Fil: Diaz Jaramillo, Mauricio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Barón, E.. Instituto de Diagnóstico Ambiental y Estudios del Agua; España. Consejo Superior de Investigaciones Científicas; España Fil: Monserrat, José María. Universidade Federal do Rio Grande; Brasil Fil: Eljarrat, E.. Instituto de Diagnóstico Ambiental y Estudios del Agua; España. Consejo Superior de Investigaciones Científicas; España Fil: Barceló, D.. Instituto de Diagnóstico Ambiental y Estudios del Agua; España. Consejo Superior de Investigaciones Científicas; España

Phytoremediation is a low-cost alternative technology based on the use of plants to remove pollutants from the environment. Persistent organic pollutants such as DDTs with a long half-life in soils are attractive candidates for remediation. This study aimed to determine the potential of antioxidant response use in the evaluation of plants' tolerance for selecting species in phytoremediation purposes. Alfalfa and soybean plants were grown in DDT contaminated soils. After 60 days, growth, protein content, antioxidant capacity, GST activity, concentration of proteic and non-proteic thiol groups, chlorophyll content and carotenoid content were measured in plant tissues. Results showed no effect on alfalfa or soybean photosynthetic pigments but different responses in the protein content, antioxidant capacity, GST activity and thiol groups on roots, stems and leaves, indicating that DDTs affected both species. Soybean showed higher susceptibility than alfalfa plants due to the lower antioxidant capacity and GST activity in leaves, in spite of having the lowest DDT accumulation. This study provides new insights into the role of oxidative stress as an important component of the plant's response to DDT exposure. Fil: Mitton, Francesca María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Ferreira, Josencler L. Ribas. Universidade Federal de Rio Grande; Brasil Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Monserrat, José María. Universidade Federal de Rio Grande; Brasil

The use of carbon nanomaterials (CNMs) is growing in different technological fields, raising concern on their potential impacts on the environment. Given its diverse nanothenological applications, graphene oxide (GO) stands out among the most widely used CNMs. Its hydrophilic capacity enables it to remain stable in suspension in water allowing that GO can be accessible for accumulation by aquatic organisms through ingestion, filtration and superficial dermal contact when present in aquatic ecosystems. Considering that the effects induced to aquatic organisms may depend on environment characteristics, such as temperature, salinity, water pH as well as the presence/absence of sediment, the present study aimed to investigate the influence of sediment on the impacts caused by GO exposure. For this, oxidative stress parameters were measured in the clam Ruditapes philippinarum, exposed to different GO concentrations (0.01, 0.1 and 1 mg/L), in the presence and absence of sediment, for a 28-days experimental period. The results here presented showed that regardless the presence or absence of sediment, most of the biochemical parameters considered were altered when clams were exposed to the highest concentration. The present findings further revealed that in the presence of sediment, clams mostly invested in non-enzymatic defenses (such as reduced glutathione, GSH), while animals exposed to GO in the absence of sediment favored their enzymatic antioxidant defense capacity (catalase, CAT and superoxide dismutase, SOD). This study highlights the relevance of environmental variations as key factors influencing organisms' responses to pollutants.

Arsenic (As) is one of the most widespread contaminants; it is found in almost every environment. Its toxic effects on living organisms have been studied for decades, but the interaction of this metalloid with other contaminants is still relatively unknown, mainly whether this interaction occurs with emerging contaminants such as nanomaterials. To examine this relationship, the marine shrimp Litopenaeus vannamei was exposed for 48 h to As, graphene oxide (GO; two different concentrations) or a combination of both, and gills, hepatopancreas and muscle tissues were sampled. Glutathione S-transferase (GST)-omega gene expression and activity were assessed. As accumulation and speciation (metabolisation capacity) were also examined. Finally, a molecular docking simulation was performed to verify the possible interaction between the nanomaterial and GST-omega. The main finding was that GO modulated the As toxic effect: it decreased GST-omega activity, a consequence related to altered As accumulation and metabolism. Besides, the molecular docking simulation confirmed the capacity of GO to interact with the enzyme structure, which also can be related to the decreased GST-omega activity and subsequently to the altered As accumulation and metabolisation pattern.

Background Nematodes are used in many different fields of science, including environmental and biomedical research. Counting and/or estimating nematode numbers is required during research. Although being one of the most common procedures, this apparently simple task is a time-consuming process, prone to errors and concerns regarding procedure, reliability, and accuracy. When an estimate is necessary, there is a traditional manual counting procedure that in this study it will be called as “drop method” (DM). This popular method that extrapolates an animal count from a small drop of fluid shows a high coefficient of variation. To solve this problem, the present study used the free-living nematode Caenorhabditis elegans to develop a new estimation procedure that was based on a relationship between area and volume of a larger sample. Results The new method showed a low coefficient of variation and a close relationship between estimated and real counts of the total number of nematodes in large C. elegans suspensions. Reactive oxygen concentration was measured as an example of method application and to allow comparison between methods. Conclusion The proposed method is accurate, facile and reproducible, requiring simple, inexpensive materials that make it an excellent alternative to the DM manual counting procedure. Although the DM is faster, its estimates are not as accurate or as precise as those of the new proposed method. Electronic supplementary material The online version of this article (10.1186/s12575-018-0089-2) contains supplementary material, which is available to authorized users.

Este estudo investigou o uso de enzimas exógenas em dietas para juvenis de pampo prateado Trachinotus marginatus. Foram preparadas seis dietas (43% de proteí­­na, 8% de lipí­­dio), contendo 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250) e 500 (T500) mg kg-1 do complexo enzimático Rovabio ® Max AP. Avaliou-se os efeitos sobre o crescimento, composição de carcaça, ní­­veis de glicogênio e triglicerí­­deo no fí­­gado e possí­­veis alterações na morfologia do intestino e fí­­gado. Os resultados mostraram diferença significativa (p < 0,05) no desempenho de crescimento dos peixes dos tratamentos T100, T250 e T500, com grande concentração de triglicerí­­deos e alteração na morfologia do fí­­gado nos peixes dos tratamentos T250 e T500. A concentração de cálcio nos ossos também teve um aumento significativo (p < 0,05) nos peixes dos tratamentos T50, T100 e T250 em relação ao controle. Entretanto, não houve diferença significativa (p > 0,05) na composição de carcaça, morfologia do intestino e concentração de glicogênio no fí­­gado.Esses resultados indicam que o uso de 100 mg kg-1 de enzimas na dieta mostrou ser o melhor ní­­vel de inclusão para juvenis de pampo prateado, favorecendo o crescimento e a concentração de cálcio nos ossos. Sem efeitos significativos sobre os ní­­veis de triglicerí­­deos no fí­­gado

Few data are available about the effect of dimethylated forms (DMA) on aquatic organisms. As rarely a contaminant occurs alone, studies evaluating the combined effect of different contaminants in aquatic organisms are needed. In fact, the presence of nanomaterials, such as titanium dioxide nanoparticles (nTiO

Particulate matter (PM) contains different chemical substances that have been associated with health effects and an increased risk of mortality due to their toxicity. In this study, fine particulate matter (PM2.5) samples were collected in a region with rural characteristics (Seropedica (Se)) and another with some industries (Duque de Caxias (DC)) (Brazil, RJ). Rats were exposed to PM2.5 extracts daily for 25 days at different dilutions: 10×, 5×, and a concentrated solution (CS). Biochemical analyses were investigated for total antioxidant capacity (ACAP), lipid peroxidation (LPO) levels, reduced glutathione (GSH) concentration, activity of glutamate cysteine ligase (GCL), and activity of glutathione S-transferase (GST). The liver showed a significant increase in GCL (DC-5×, DC-CS and Se-CS) and GST activities (DC-CS and Se-CS) in both regions when compared to the control group. In the renal cortex, GCL activity decreased in most of the tested groups while GST activity increased only in the 5× groups of both regions (DC and Se). In the renal medulla, GCL activity decreased for Se-10× and DC-CS but increased for Se-5×, and GST activity increased in the Se-10×, DC-5×, and DC-CS groups. Lung GCL increased in all groups for both regions. Moreover, this organ also showed an increase in GST activity when higher metal concentrations were present (5× and CS). TBARS levels were increased for all tissues in most tested concentrations. These data indicate that soluble compounds (e.g., metals) from PM2.5 sampled in areas with different pollution indexes can change the redox status and cause damage to different tissues.

The overflow of scientific literature stimulates poor reading habits which can aggravate science's reproducibility crisis. Thus, solving the reproducibility crisis demands not only methodological changes, but also changes in our relationship with the scientific literature, especially our reading habits. Importantly, this does not mean reading more, it means reading better.

Topographical organization can be found in many areas of the cerebral cortex, although its presence in higher order cortices is debated. Some studies evaluated whether this pattern of organization is present in the hippocampus, trying to determine whether hippocampal place cells are organized around a topographical map of space. Those studies indicated that the topographical organization of hippocampal place cells is either very limited or simply nonexistent. In this paper, we argue for a different interpretation of available evidence and suggest that there is a topographical organization in hippocampal place cells, but the topographical map formed is not a map of the physical space. Although place cell firing is correlated with the animal's position and is important to spatial navigation, place cells encode much more information than just location. Thus, we should not expect the topographical map to be organized around physical space, but around an abstract, multidimensional space containing the receptive fields of place cells. We show that this conclusion is supported by two of the main theories of hippocampal function-cognitive map theory and index theory-which, when carefully analyzed, make exactly the same predictions about hippocampal topography. Such abstract topographical map would be extremely hard to find using the methods commonly employed in the literature, but there are some approaches that may, in the future, make possible to characterize the topographical organization in the hippocampus and other high-order brain regions.

Microcystin-leucine arginine (MC-LR) is a natural toxin produced by cyanobacterial blooms that causes severe liver damage in fish. It is crucial to investigate if housekeeping genes are affected by MC-LR in zebrafish, to permit the adequate evaluation of gene expression by RT-qPCR. We evaluated the gene expression stability (M value) and regulation by chemical treatment (using E

EMBO Reports (2018) e46008 Science appears to be in a crisis caused by the failure to replicate published results, which is undermining confidence in the scientific literature. This reproducibility crisis is not only evident in large‐scale replication efforts to evaluate studies from various laboratories [1], but also within laboratories themselves [2]. The problem has been extensively discussed among the scientific community, as many scientists have had troubles with replication themselves [3]. A recent survey of 1,576 researchers found that around 90% agreed that the reproducibility crisis is real [3]. There are many factors that influence the reproducibility of published results, including statistical methods, publication bias, lack of transparency, insufficient detail in the description of methods and variability of conditions and protocols between laboratories [1], [2], [4]. Some of these, such as lack of transparency and insufficient detail, directly impair scientists’ ability to properly evaluate a study and to replicate the experiments. Others, such as misuse of statistics and publication bias, lead to systematic biases that undermine the reliability of the entire literature. But there is another, even more insidious factor that has received considerably less attention: random variation. A few years ago, Halsey et al [5] published a commentary on the sample‐to‐sample variability of the P ‐value. They showed that with low statistical power—which is ubiquitous in the literature—the P ‐value can vary widely between samples of the same populations. As part of …

Graphene has been shown to induce toxicity in mammals and marine crustaceans; however, information regarding oxidative stress in fish is scarce. The aim of this study was to evaluate the mechanism of graphene toxicity in different tissues of Danio rerio, considering different parameters of stress. Animals were injected intraperitoneally (i.p.) with 10 μL of suspensions containing different graphene concentrations (5 and 50 mg/L); the gills, intestine, muscle and brain were analysed 48 h later. There was no significant difference in the expression of the gclc (glutamate cysteine ligase catalytic subunit) and nrf2 (nuclear factor (erythroid-derived 2)-like 2) genes after exposure. In contrast, glutamate cysteine ligase (GCL) and glutathione-S-transferase (GST) activities were modulated and the glutathione (GSH) concentration was reduced in different tissues and at different concentrations. Lipid damage was observed in the gills. Histological analyses were performed to observe if the exposure could induce pathological damage in these tissues. The results showed pathological effects in all tissues, excluding the intestine, after exposure to both concentrations. Overall, these results indicate that graphene induces different grades of toxicological effects that are dependent on the analysed organ, with distinct pathological effects on some and oxidative effects on others. However, the brain and gills seem to be the primary target organs for graphene toxicity.

The study of key molecular mechanisms of mitochondrial dysfunctions, which are responsible for neurodegenerative diseases, is a critical step to assist for the diagnosis and therapy success. In this regard, we suggest an alternative of treatment on neurodegenerative disorders-based on Single-Walled Carbon Nanotubes (SWCNT) as potential mito protective -(Phe)-F0-ATPase targeting nanoparticles toward Precision Molecular Nanomedicine against pathological ATP-hydrolysis conditions. Herein, we used ab initio computational simulation to analyze the structural and electronic properties from SWCNT-family with zigzag topologies (n, m - Hamada indices n > 0; m = 0) like: SWCNT-pristine, SWCNT-COOH, SWCNT-OH, SWCNT-monovacancy interacting with the critical (Phe)-residues of the mitochondrial F0-ATPase and using oligomycin A (specific Phe-F0-ATPase inhibitor) as reference control. Then, we show that the SWCNT-family can be potentially used to selectively inhibit the (Phe)-F0-ATPase activity liked to pathological mitochondrial ATP-hydrolysis associated to human neurodegenerative disorders by using DFT-ab initio simulation. The in-silico results suggest the formation of more stable complexes of interaction following the order: SWCNT-COOH/F0-ATPase complex (1.79 eV) > SWCNT-OH/F0-ATPase complex (0.61 eV) > SWCNT/F0-ATPase complex (0.45 eV) > SWCNT-monovacancy/F0-ATPase complex (0.43 eV) based on the strength of the chemisorption interactions. These theoretical evidences open new horizons towards mito-target precision nanomedicine.

Interactions between the single walled carbon nanotube (SWCNT) family and a mitochondrial ADP/ATP carrier (ANT-1) were evaluated using constitutional (functional groups, number of carbon atoms, etc.) and electronic nanodescriptors defined by (n, m)-Hamada indexes (armchair, zig-zag and chiral). The Free Energy of Binding (FEB) was determined by molecular docking simulation and the results showed that FEB was statistically more negative (p SWCNT-OH > SWCNT, suggesting that polar groups favor the anchorage to ANT-1. In this regard, it was showed that key ANT-1 amino acids (Arg 79, Asn 87, Lys 91, Arg 187, Arg 234 and Arg 279) responsible for ADP-transport were conserved in ANT-1 from different species examined to predict SWCNT interactions, including shrimp Litopenaeus vannamei and fish Danio rerio commonly employed in ecotoxicology. The SWCNT-ANT-1 inter-atomic distances for the key ANT-1 amino acids were similar to that with carboxyatractyloside, a classical inhibitor of ANT-1. Significant linear relationships between FEB and n-Hamada index were found for zig-zag SWCNT and SWCNT-COOH (R2 = 0.95 in both cases). A Perturbation Theory-Nano-Quantitative Structure-Binding Relationship (PT-NQSBR) model was fitted that was able to distinguish between strong (FEB < −14.7 kcal mol−1) and weak (FEB ≥ −14.7 kcal mol−1) SWCNT–ANT-1 interactions. A simple ANT-1-inhibition respiratory assay employing mitochondria suspension from L. vannamei, showed good accordance with the predicted model. These results indicate that this methodology can be employed in massive virtual screenings and used for making regulatory decisions in nanotoxicology.

The purpose of this study was to evaluate the effect of water temperature on the antioxidant (gills, hemolymph and hepatopancreas) and immunological systems (hemolymph) of Litopenaues vannamei reared with no water exchange. A 60-day trial was conducted at different temperatures (15, 21, 27—control and 33 °C), with 3 replicate tanks for each treatment. The immunologic parameters analyzed were as follows: hyaline and granular hemocyte count, total protein and apoptosis. The enzymatic and lipid peroxidation assays consisted of glutamate cysteine ligase (GCL), reduced glutathione (GSH) and thiobarbituric acid-reactive substances (TBARS). There were no significant differences (p > 0.05) in immunological parameters among treatments throughout the experimental period. Shrimp exposed to 15 °C at 30 days exhibited significantly higher GCL activity in gills compared to 21 °C (1166.28%), 27 °C (422.96%) and 33 °C (809.37%). L. vannamei reared at 15 °C had the highest GSH concentration at 30 days. The GSH increase in gills was 390.29, 376.94 and 361.75% at 21, 27 and 33 °C, respectively. On day 30, shrimp subjected to 33 °C had higher TBARS levels (6157.14; 8620.00 and 14,336.66% at 15, 21 and 27 °C, respectively). Shrimp reared at 15 °C exhibited higher activity of the rate-limiting compound for GSH production (GCL) and higher concentrations of this non-enzymatic antioxidant. This increased activity may counteract the overproduction of reactive oxygen species generated by temperature stress. We further noted that at 33 °C, the animals showed higher lipid peroxidation. The lowest stress response was observed in shrimp reared at 27 °C (the control group). Therefore, the extreme temperatures should be avoided. Statement/relevance This study present new results about handling and welfare.

The White Shrimp (Litopenaeus vannamei) is reared in several types of systems. Changes in pH in some can produce sub-lethal effects that result in poor growth and survival. The aim of the present study was to determine the acidic and basic pH 50% lethal limits after 96 h exposure (pH50–96 h) and to evaluate the sub-lethal effects of pH on oxidative stress parameters in juvenile L. vannamei. The experimental design comprised nine treatments with three replications of each. The nine treatments consisted of pH 10.5, 10.0, 9.5, 9.0, 7.0, 5.0, 4.5, 4.0 and 3.5. The treatment at 7.0 was used as the control. The sub-lethal pH tests were: basic pH 9.5, neutral pH 7.0 (control) and acidic pH 4.5. For each experimental pH and sampling point, the hemolymph of six shrimp was collected to determine catalase and glutathione S-transferase’s activities and total antioxidant capacity. The values of lethal pH50 at 24, 48, 72 and 96 h for juvenile L. vannamei had basic pH values equal to 9.82, 9.62, 9.59 and 9.58 and acidic...

This study aimed to evaluate the effects of adding guar gum, a non-starch polysaccharide, to the diet of Mugil liza juveniles. The juveniles (mean weight = 0.38 ± 0.01 g) were fed one of three diets with increasing supplement levels (4%, 8%, and 12%) and a control diet without additional gum for 60 days, in order to evaluate the effects on zootechnical performance, proximate composition, liver parameters, morphological alterations to the intestinal tract, and modulation of gastrointestinal microbiota. The animals fed 8% and 12% gum presented a significantly lower mean final weight, weight gain, specific growth rate, food intake rate, and protein intake rate than the control. Adding gum to the diets also reduced the dry matter, crude protein, and carcass fat levels. All treatments with added gum resulted in increased liver glycogen, and the cholesterol levels were significantly reduced in fish fed 4% and 8% supplement levels. No intestinal morphological alterations were observed in the animals. However, a modulating effect was noted on the microbial community, altering the bacterial quantity and composition throughout the tract segments. The use of guar gum is not recommended in Mugil liza diets, at least above 4%.

Shrimp (Litopenaeus vannamei) reared in a conventional seawater (SW) aquarium system SW were compared with those raised in a biofloc technology (BFT) system. After 30 days, the L. vannamei shrimp were euthanized and samples of gills, hepatopancreas and muscle were dissected. Statistical analysis was performed using bi-factorial ANOVA, with the factors of the treatment (shrimp reared in SW or in a BFT system) and organs (gills, hepatopancreas and muscles). No differences (p > 0.05) in glutathione-S-transferase activity were observed between shrimp reared in SW and shrimp reared in BFT (p 0.05). Overall, the results showed that rearing shri...

Biochemical biomarkers were evaluated in the barnacle Balanus improvisus (Crustacea: Cirripedia) sampled from both polluted and reference sites in the Patos Lagoon Estuary, Southern Brazil. During winter, higher glutathione S-transferase (GST) activity was recorded in the barnacles from the polluted sites, indicating environmental exposure to contaminants. Relatively low lipid peroxide levels (LPO) were also observed in barnacles from polluted sites, indicating that oxidative stress by lipid peroxidation was not a major threat in barnacles from those sites. Seasonal differences in the GST and total oxyradical scavenging capacity (TOSC) could have contributed to the low LPO levels in the summer relative to the levels in the winter. Catalase activity and metallothionein levels were not affected by contamination or seasonality. The seasonal changes observed in biomarker responses were paralleled by the differences in temperature, which could have affected physiological responses, including the balance between pro-oxidants and antioxidants.

Summary The aim of this study was to evaluate whether increasing the levels of citrus pectin has anti-nutritional effects when included in the diets of Mugil liza juveniles, including its effects on hepatic metabolism and modulation of the microbial community. Fish (mean weight 0.38 g � 0.01) were stocked at a density of 15 fishes per tank and fed for 60 days with either a control diet or one of three diets containing different levels of pectin (4, 8 and 12%), in triplicates. The temperature, dissolved oxygen, pH, salinity and alkalinity during the trial were, respectively, 25.0°C � 0.1, 6.82 � 0.02 mg L � 1 , 8.10 � 0.06 and 147 mg � 12.93 CaCO3. The total ammonia-nitrogen (TAN) in PC4, PC8 and PC12 treatments were, respectively, 0.69 � 0.38; 0.57 � 0.35; 0.64 � 0.39 and 0.45 � 0.23 mg L � 1 . The increasing diet viscosity with pectin inclusion did not cause significant differences in growth. Fish fed with pectin demonstrated a reduction in their percentage body dry matter, crude protein and ash. Hepatic glycogen levels were elevated in the group fed with 12% pectin, while there were no effects in cholesterol and triglycerides levels. Citrus pectin did not exert any modulatory effect on the microbial community. Although the pectin-supplemented fish showed enteritis during the experimental period, this did not impair animal performance. However, the use of this polysaccharide as a binder in mullet (Mugil liza) diets for longer periods should be considered with caution.

Carbon nanotubes (CNT) are promising materials for biomedical applications, especially in the field of neuroscience; therefore, it is essential to evaluate the neurotoxicity of these nanomaterials. The present work assessed the effects of single-walled CNT functionalized with polyethylene glycol (SWCNT-PEG) on the consolidation and retrieval of contextual fear memory in rats and on oxidative stress parameters in the hippocampus. SWCNT-PEG were dispersed in water at concentrations of 0.5, 1.0, and 2.1 mg/mL and infused into the rat hippocampus. The infusion was completed immediately after training and 30 min before testing of a contextual fear conditioning task, resulting in exposure times of 24 h and 30 min, respectively. The results showed that a short exposure to SWCNT-PEG impaired fear memory retrieval and caused lipid peroxidation in the hippocampus. This response was transient and overcome by the mobilization of antioxidant defenses at 24 h. These effects occurred at low and intermediate but not high concentration of SWCNT-PEG, suggesting that the observed biological response may be related to the concentration-dependent increase in particle size in SWCNT-PEG dispersions.

Mitochondrial Permeability Transition Pore (MPTP) is involved in neurodegeneration, hepatotoxicity, cardiac necrosis, nervous and muscular dystrophies. We used different experimental protocols to determine the mitoprotective activity (%P) of different carbon nanotubes (CNT) against mitochondrial swelling in multiple boundary conditions (bj). The experimental boundary conditions explored included different sub-sets of combinations of the following factors b0 = three different mitochondrial swelling assays using the MPT-inductor (Ca2+, Fe3+, H2O2) combined or not with a second MPT-inductor and swelling control assays using MPT-inhibitor (CsA, RR, EGTA), b1 = exposure time (0–600 s), and b2 = CNT concentrations (0–5 μg ml−1). Other boundary conditions (bk) changed were the CNT structural parameters b3 = CNT type (SW, SW + DW, MW), b4 = CNT functionalization type (H, OH, COOH). We also changed different of CNT like b5 = molecular weight/functionalization ratio (minW/maxW) or b6 = maximal and minimal diameter (Dmin/Dmax) as physic-chemical properties (Vk). Next, we employed chemoinformatics ideas to develop a new Perturbation Theory (PT) model able to predict the %P of CNT in multiple experimental conditions. We investigated different output functions of the absorbance ′f(eij) used in PL4/PL5 methods like (eij, 1/eij, 1/eij2, or −log eij) as alternative outputs of the model. The inputs are in the form an additive functions with linear/non-linear terms. The first term is a function 0f(〈eij〉) of the average absorbance 〈eij〉 (expected value) in different assays (bj). The concentration dependent terms are linear functions of concentration, or hill-shaped curves similar to PL4/PL5 functions (used in dose–response analysis). The CNT structure perturbation terms are linear/non-linear functions of Box–Jenkins operators (ΔVkj). The ΔVkj are moving averages (deviations) of the Vk of the CNT with respect to their expected values 〈Vkj〉. The best model found predicted the values of absorbance (measure of mitoprotective activity vs. mitochondrial swelling) with regression coefficient R2 = 0.997 for >6000 experimental data points (q2 = 0.994). Last, we used the model to carry out a simulation of the changes on mitoprotective activity for CNT family after one increase of 1–10% of the minWi and maxDi of CNT.

[Abstract] This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of Jm showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of Jm for other CNTs was provided by random forest using eight features, obtaining test R-squared (R2) of 0.863 and test root-mean-square error (RMSE) of 0.0461. The results demonstrate the capability of encoding CNT information into spectral moments of the Raman star graphs (SG) transform with a potential applicability as predictive tools in nanotechnology and material risk assessments Instituto de Salud Carlos III; PI13/02020 Instituto de Salud Carlos III; PI13/00280 Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; R2014/025 Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; GRC2014/049 Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; R2014/039 Ministerio de Economía y Competitividad; UNLC08-1E-002 Ministerio de Economía y Competitividad ; UNLC13-13-3503 Ministerio de Economía y Competitividad; CTQ2016-74881-P País Vasco.Gobierno; IT1045-16 Brasil. Conselho Nacional de Desenvolvimento Científico e Tecnológico; 308539/2016-8 Brasil. Conselho Nacional de Desenvolvimento Científico e Tecnológico; 454332/2014-9

The buckminsterfullerene (C60) is considered as a relevant candidate for drug and gene delivery to the brain, once it has the ability to cross the blood-brain barrier. However, the biological implications of this nanomaterial are not fully understood, and its safety for intracerebral delivery is still debatable. In this study, we investigated if C60 particle size could alter its biological effects. For this, two aqueous C60 suspensions were used with maximum particle size up to 200nm and 450nm. The suspensions were injected in the hippocampus, the main brain structure involved in memory processing and spatial localization. In order to assess spatial learning, male Wistar rats were tested in Morris water maze, and the hippocampal BDNF protein levels and gene expression were analyzed. Animals treated with C60 up to 450nm demonstrated impaired spatial memory with a significant decrease in BDNF protein levels and gene expression. However, an enhanced antioxidant capacity was observed in both C60 treatments. A decrease in reactive oxygen species levels was observed in the treatments with suspensions containing particles measuring with up to 450nm. Thiobarbituric acid reactive substances, glutamate cysteine ligase, and glutathione levels showed no alterations among the different treatments. In conclusion, different particle sizes of the same nanomaterial can lead to different behavioral outcomes and biochemical parameters in brain tissue.

Background Curcumin (CUR) has properties that can be useful for the treatment of Alzheimer's disease. Such properties are the inhibition of amyloid-β-protein (Aβ) aggregation, Aβ-induced inflammation, and activities of β-secretase and acetylcholinesterase. However, previous studies have revealed that CUR exhibited low bioavailability and difficulties in reaching the brain. Objective To overcome such drawbacks, this study aims at developing nasal lipid nanocarriers loaded with CUR to effectively target the brain. Methods The lipid nanocarriers (NE) were prepared using the hot solvent diffusion associated with the phase inversion temperature methods. Physico-chemical and morphological characterizations and in vitro drug release of the nanocarriers were carried out. The CUR permeation/retention was analyzed in Franz-type diffusion cell using porcine nasal mucosa. Confocal laser scan and histopathological studies were also performed. Results The results showed that the NE sizes ranged between 18 nm and 44 nm with negative zeta potential. The CUR content ranged from 0.24 to 1.50 mg/mL with an encapsulation efficiency of 99%. The profiles of CUR release indicated a biphasic kinetics. CUR-NE permeation across the porcine nasal mucosa was higher when compared to free CUR. These results have also been validated through an analysis on a confocal microscopy. In addition, no toxicity on the nasal mucosa has been observed in a histopathological analysis. Conclusion These results suggest that it is possible to develop NEs with a high content of CUR and small particle size. Such an encapsulation increases the potential of CUR permeation across the porcine nasal mucosa.

Soil contamination by organic compounds is of great concern worldwide since it could act as a major environmental repository. The success of phytoremediation is conditioned by two main factors: the availability and toxicity of the compound to be remediated, and the plant species ability to incorporate or degrade the contaminants. This study aimed to assess the potential of different plants species for remediation of aged DDTs residues in soil. Tomato, sunflower, soybean and alfalfa plants were grown in contaminated soils (p,p′-DDE 455.3, p,p′-DDT 63.5 ng g−1 dry weight) for 15 and 60 days. Phytoremediation was evaluated by studying the pollutant dynamics in the soil–plant system and lipid peroxidation (LPO) as an effect biomarker. Results showed that soil DDTs levels were diminished after 60 days of plant growth, due to the combined effect of DDTs uptake by roots and rhizospheric degradation. The relative accumulation of each compound was dependent on soil levels (p,p′-DDE > p,p′-DDT > p,p′-DDD) and all species presented root >aerial accumulation pattern, evidencing DDTs translocation. Tomato plants were the most effective in the enhancement of pollutants bioavailability in the rizospheric soil. Plants growth induced physicochemical changes in soil and those are evidenced by increasing dehydrogenase activity and DDTs metabolism, mainly in soybean and tomato soil fractions. Root bioconcentration factors >1 were observed in 15 days tomato and alfalfa plants. Growth dilution effect was observed in roots of all species at 60 days, except soybean. DDTs uptake nor affected tomato and alfalfa plants growth neither caused oxidative stress. Considering the accumulation potential, tolerance (expressed as no evident phytotoxicity effects) and interaction with soil matrix in terms of metabolism and availability, tomato plants seems to be the best phytoremediator candidates for aged soil DDTs residues. Fil: Mitton, Francesca María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Shimabukuro, Valeria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Monserrat, José María. Universidade Federal do Rio Grande do Sul; Brasil

The effect of lipoic acid supplementation and moderate hypoxia (3 mg/L), followed by re-oxygenation, was analyzed in terms of antioxidant and oxidative damage responses in juvenile shrimp Litopenaeus vannamei. Lipoic acid (LA)-enriched rations (D1: 76.4 ± 6.4; D2: 196.4 ± 70.2; and D3: 397.2 ± 79.97 mg LA/kg) were offered to shrimps. A control group without LA adding was also run. After 45 days, LA-enriched ration increased the activity of the detoxifying enzyme glutathione-S-transferase in gills. Total antioxidant capacity against peroxy radicals was augmented in gills and hepatopancreas at doses D2 and D3. Doses D1 and D2 of LA reduced the levels of oxidative damage (lipid peroxidation) in gills and hepatopancreas. The results showed that certain LA doses (particularly D2) improved not only antioxidant responses but also weight gain. It can be concluded that LA triggered antioxidant and detoxification protection in L. vannamei, allowing the shrimp to cope with environmental stressful factors.

This study analyzed the growth and biochemical responses of six bacterial colonies isolated from the mucus of the estuarine polychaeta Laeonereis acuta (Nereididae) after exposure to a water suspension of fullerene (nC60) and nanosilver (nAg) separately (0.01; 0.10; and 1.00 mg/L) and together (0.01; 0.10; and 1.00 mg/L of nanosilver and 1.00 mg/L of fullerene added to each nAg concentration). Exposures were performed in darkness during 24 h and then samples were taken from the worms and inoculated on agar during 24 h to analyze colonies growth. After this the material was analyzed biochemically. Colonies growth (tested by wet biomass weight) was inhibited at 0.01 and 0.10 mg/L of nAg and 0.01 and 0.10 mg/L nAg + constant 1.00 mg/L of nC60 (p < 0.05). Lipid peroxidation damage was significant from the control for the concentrations of 0.01 and 0.10 mg/L of nC60 and glutathione-S-transferase (GST) activity was significantly higher for the concentration of 1.00 mg/L mg/L nAg + constant 1.00 mg/L of nC60 (p < 0.05). Although nC60 did not induced growth inhibition, it triggered lipid peroxidation alone and increased GST activity together with nAg.60 Contrary to nC60, nanosilver inhibited bacterial growth, although the biochemical measurements indicate that this response is not due to reactive oxygen species generation.

A B S T R A C T Saxitoxins (STXs) are neurotoxins produced by cyanobacteria such as Cylindrospermopsis raciborskii. During bloom events, the production of these compounds causes contamination on public water supply sources. STXs block voltage gated sodium channels and can lead to severe poisoning and death of organisms at different trophic levels. Other toxicity mechanism of STX is the generation of reactive oxygen species (ROS). The aim of this study was to investigate the effect of consumption of water contaminated with a C. raciborskii strain (producing variants of Neo-STX and STX) by rats during 30 days through the analysis of oxidative stress biochemical parameters. Total antioxidant capacity (ACAP) and oxidative stress parameters were analyzed at pre-frontal cortex, hippocampus and liver of adult Wistar rats (2–3 months old). Treated animals ingested concentrations of 3 and 9 mg/L of STX equivalents and were compared with a control group (culture medium ASM-1). At the concentration of 3 mg/L, a decrease in ROS production associated with lower ACAP at hippocampus was observed. Furthermore, a decrease of glutamate cysteine ligase (GCL) activity in the cortex and an increase of brain and liver glutathione concentration were also observed. At the highest concentration (9 mg/L), there was an ACAP increase in the hippocampus as well as in the activity GCL and glutathione-S-transferase in the cortex and hippocampus. At both concentrations, lipid peroxidation was registered in the liver. Therefore, chronic ingestion of STXs can alter the antioxidant defenses and induce oxidative stress in brain and liver. The present results point to the values adopted as threshold limit for STXs in potable waters (3 mg/L) shows already significant chronic effects that alter antioxidant defenses and induce oxidative stress at least in two of the organs studied.

Despite arsenic being one of the most widely distributed toxicants over the world, its reported occurrence in Latin America is relatively low when compared to North America, Europe, and Asia. Regardless, it still requires proper assessment; especially considering its potential interaction with other new contaminants, such as nanomaterials. In the present study, a brief introduction to arsenic contamination in Latin America is made, its main methods of intake by humans are described, and concerns regarding its interaction with other contaminants, especially nanomaterials, are presented. A multigenerational approach through five generations of Caenorhabditis elegans was performed to assess, at ecotoxicological relevant concentrations, the toxic effects of arsenic/nanomaterial interaction through the measurement of biochemical and physiological parameters. The reactive oxygen species (ROS) and lipid peroxidation levels were assessed, levels of reduced glutathione (GSH) determined, and the enzyme activities of glutamate cysteine ligase (GCL), glutathione-S-transferase (GST), and catalase (CAT) were measured. Fertility, reproduction, and growth parameters were also assessed and compared. A nanomaterial modulatory effect was found to accentuate the toxicity of arsenic on some of the most important enzymes in the antioxidant defense system; deleterious effects were also found in the development and reproduction of the animals throughout the generations. This work shows that multigenerational approaches can unveil toxic effects that would remain cryptic when evaluated in only one generation.

This paper discusses how our bad reading habits are starting to influence how we write. This short abstract and the picture next to it summarize the arguments in this paper. Just kidding, they do not. One really needs to read the paper for that.

Farfantepenaeus brasiliensis juveniles (5.53 ± 1.20 g) were subjected to different temperatures to evaluate the optimal temperature for transport. The shrimp were acclimated in a 4000 L tank at 22.4 °C and salinity of 22‰. The shrimp were then transported for 12 h at different temperatures (16.0, 19.3, 22.4 (control), 25.0 or 28.0 °C) in transparent plastic bags containing one-third water (10 L) and two-thirds pure oxygen, with three repetitions for each treatment. Analysis was performed at the beginning and the end of the transport. The hemolymph from five shrimp in each plastic bag was collected to measure catalase (CAT), glutathione- S -transferase (GST) and total antioxidant capacity against peroxyl radicals. The results showed that shrimp transported in lower temperatures presented higher antioxidant competence and the best water quality parameters. Therefore, the temperature we recommend for transporting F. brasiliensis is 19.3 °C, which enhanced activities of CAT and GST and provided better water quality conditions.

A 10-day trial was conducted to evaluate the effect of temperature on the antioxidant system of Litopenaeus vannamei in a biofloc technology system. Four treatments in triplicate tanks were assigned to the following temperatures: 15, 21, 27 (control), and 33 °C and the water quality parameters were monitored every day. For all enzyme assays, the hemolymph cells lysate of six shrimp per treatment was collected. Lipid peroxidation (LPO) was assessed by determining the content of thiobarbituric acid-reactive substances (TBARS); the activities of catalase (CAT) and glutathione-S-transferase (GST) were also evaluated. The results of TBARS showed that shrimp reared at 15 and 21 °C presented an increase of 407% (240 h) and 339% (120 h), respectively. L. vannamei exposed to 15 °C augmented in 186% (24 h) the activity of CAT. Moreover, shrimp of 21 °C group also increased CAT activity in 228% (6 h). GST presented the strongest variation reaching 1437% in shrimp of 15 °C for 6 h and 1425% of the 21 °C treatment at ...

Nanomaterials (NM) industry had grown in the last decade, although there are few studies concerning its potential toxicity effects on aquatic organisms. In this study the freshwater zebrafish (Danio rerio) was exposed to two kinds of carbon NM, single-wall carbon nanotubes (SWCNT) and fullerenol [C60(OH)18-22(OK4)] to analyze oxidative stress responses on fish brain. Adult zebrafish (mean mass: 0.52±0.01g) were submitted to intraperitoneal injections of SWCNT suspension and fullerenol solution (30mg/kg of fish), receiving one or two doses with a time interval of 24h. Results showed that total antioxidant capacity was lowered in brains of fish exposed 24h to fullerenol when compared to those from SWCNT treatment (p0.05). After 48h, fullerenol induced higher expression of both catalytic and regulatory subunits of enzyme glutamate cysteine ligase when compared to control group (p0.05), indicating an antioxidant behavior. In vitro assays showed a dual effect of SWCNT, since a pro-oxidant behavior was observed at low concentrations (0.1 and 1.0mg/L) and an antioxidant one at the highest concentration (10.0mg/L). Few biological responses were altered by this NM: decrease in total antioxidant capacity and induction of the expression of the transcription factor Nrf2 when compared to control group.

Lipoic acid (LA) is a water- and lipid-soluble molecule with capacity to pass through cell membranes and with several antioxidant properties. Previous studies have shown that polymeric nanocapsules with LA favor the protection of this antioxidant, increasing their physical and chemical stability compared to formulations containing free LA. The aim of this study was to evaluate and compare the effect of free LA and LA-nanocapsules on antioxidant enzymes, the concentration of reduced glutathione (GSH) and a by-product of lipid peroxidation (malondialdehyde), as well as the expression of gene coding for different forms of glutathione-S-transferase (GST) in model fish. For this, carp Cyprinus carpio (Cyprinidae) were exposed (i.p.) to different forms of LA (free and in nanocapsules) for different times (48 h, 96 h and 1 week) and the brain, liver and muscle were analyzed. Results indicated that the organs respond differently depending on the time and form in which LA was delivered. After 96 h and 1 week, a better antioxidant response was found generally in the formulation with nanocapsules. The nanocapsule composition showed to be a factor to be considered in future studies, because in some organs and exposure times empty nanocapsules promoted an antioxidant effect and in others a pro-oxidant effect.

Summary The effects of increasing levels of dietary dextrin on growth performance, body composition, blood chemistry and hepatic triglycerides and glycogen levels were evaluated for juvenile Lebranche mullet, Mugil liza Valenciennes 1836, Mugilidae). Five diets were formulated to be isonitrogenous (350 g kg−1) and isolipidic (6 g kg−1) with increasing dextrin levels (D150: 150 g kg−1; D200: 200 g kg−1; D250: 250 g kg−1; D300: 300 g kg−1; D350: 350 g kg−1). The experimental diets were offered to the fish for 34 days, four times per day, until apparent satiation. Each treatment was tested in triplicate, with nine fish per tank (mean weight 4.69 ± 0.31 g). Fish were reared in a recirculating aquatic system of 15 fibreglass tanks each containing 50 L of saltwater. Growth parameters and body composition of the mullets were not significantly affected (P > 0.05) by the dietary treatments. Plasma glucose concentration declined (P

This paper describes the study of the radical scavenging activity of the natural antioxidants rutin, quercetin, caffeic acid, ferulic acid, and resveratrol by using a substrate-free chromatographic method based on the generation of •OH radicals by the photolysis of H2O2 in a photochemical reactor. The comparative studies permitted the classification of some phenolic compounds regarding their in vitro radical scavenging properties (rutin > caffeic acid ≈ quercetin>ferulic acid > resveratrol). The results obtained by the proposed HPLC-UV/H2O2 photolysis method could be well corroborated by the other methods, which employ the generation of free radicals with different reactivity (ROO•, , and DPPH•). Furthermore, the reverse-phase chromatographic separation of the antioxidants from their sub-products generated after attacking with HO• radicals improved advantageously the selectivity of the measured signal used for calculating the radical scavenging activity.

The effects of ammonia exposure and recovery on oxidative stress parameters and histology of juvenile Brazilian flounder Paralichthys orbignyanus were evaluated. The fish were exposed to 0.12, 0.28 and 0.57 mg NH3-N L−1, plus a control, for 10 days followed by the same recovery time in ammonia-free water. Gill, liver and muscle samples (n = 9) were collected after 1, 5 and 10 days of exposure and after recovery for oxidative stress analysis (antioxidant capacity against peroxyl radicals (ACAP); glutathione S-transferase (GST) activity; lipoperoxidation levels measured through thiobarbituric acid reactive substances (TBARS) content). For histological assessment, gill, liver and brain samples were collected. Exposure to all NH3-N concentrations induced different time- and dose-dependent changes in oxidative stress parameters. Reduced antioxidant capacity of the liver and muscle and enhanced TBARS levels in the gills and liver were demonstrated. Differently, a high ammonia concentration elicited lower hepatic TBARS levels. Enhanced GST activity in all organs and increased antioxidant capacity of the gills were also observed. No ammonia-induced histopathological effects were demonstrated. After recovery, most parameters (liver ACAP, GST activity in the muscle and liver and TBARS in the gills) returned to baseline levels. However, liver TBARS and gill GST activity remained altered 0.57 mg NH3-N L−1 treatment. The recovery period also led to a decrease in gill antioxidant capacity and an increase in muscle antioxidant capacity. In conclusion, a concentration of 0.12 mg NH3-N L−1 induces oxidative stress and antioxidant responses in juvenile Brazilian flounder. Moreover, a 10-day recovery period is not sufficient to restore fish homeostasis.

The present study aimed to evaluate the effects of benzocaine and tricaine methanesulfonate on oxidative stress parameters of juvenile tambaqui tissues. Fish (n=80) were anesthetized with benzocaine (100 mg L-1) or tricaine (240 mg L-1) and two control groups were used (non-anesthetized fish and fish exposed to ethanol-only). After anesthetic induction 10 fish/anesthetic were euthanized after 3, 12 and 24 hours post-anesthesia and tissue samplings (gills, liver and brain) were performed. Samples were submitted to analyses of enzyme activity glutathione-S-transferase (GST), cellular lipid peroxidation (TBARS) and total antioxidant capacity (ACAP). ACAP increased in gills of benzocaine treatment after 12 hours. The liver showed a reduction in ACAP of tricaine treatment after 12 hours. Both anesthetic treatments showed an increase of ACAP at 24 hours compared to control group. The activity of the GST enzyme increased in the gills for treatments benzocaine and tricaine after 3 and 12 hours. Liver showed increased GST activity (benzocaine after 24 hours and tricaine after 3 and 24 hours). Lipid damage decreased in gills (both anesthetics) and brain (tricaine) after 24 hours. The results demonstrate that benzocaine and tricaine did not cause oxidative damage in juvenile tambaqui under the experimental conditions herein established.