RESUMO
The cyanotoxin cylindrospermopsin (CYN) has been postulated to cause neurotoxicity, although the studies in this concern are very few. In addition, some studies in vitro indicate its possible effects on development. Furthermore, pesticides can be present in the same environmental samples as cyanotoxins. Therefore, chlorpyrifos (CPF) has been one of the most common pesticides used worldwide. The aim of this report was to study the effects of CYN, isolated and in combination with CPF, in a developmental neurotoxicity in vitro model. The human neuroblastoma SH-SY5Y cell line was exposed during 6 days of differentiation to both toxics to study their effects on cell viability and neurite outgrowth. To further evaluate effects of both toxicants on cholinergic signaling, their agonistic and antagonistic activities on the α7 homomeric nicotinic acetylcholine receptor (nAChR) were studied upon acute exposure. Moreover, a transcriptomic analysis by qPCR was performed after 6 days of CYN-exposure during differentiation. The results showed a concentration-dependent decrease on both cell viability and neurite outgrowth for both toxics isolated, leading to effective concentration 20 (EC20) values of 0.35 µM and 0.097 µM for CYN on cell viability and neurite outgrowth, respectively, and 100 µM and 58 µM for CPF, while the combination demonstrated no significant variations. In addition, 95 µM and 285 µM CPF demonstrated to act as an antagonist to nicotine on the nAChR, although CYN up to 2.4 µM had no effect on the efficacy of these receptors. Additionally, the EC20 for CYN (0.097 µM) on neurite outgrowth downregulated expression of the 5 genes NTNG2 (netrin G2), KCNJ11 (potassium channel), SLC18A3 (vesicular acetylcholine transporter), APOE (apolipoprotein E), and SEMA6B (semaphorin 6B), that are all important for neuronal development. Thus, this study points out the importance of studying the effects of CYN in terms of neurotoxicity and developmental neurotoxicity.
Assuntos
Alcaloides , Clorpirifos , Toxinas de Cianobactérias , Neuroblastoma , Síndromes Neurotóxicas , Praguicidas , Humanos , Clorpirifos/toxicidade , Receptor Nicotínico de Acetilcolina alfa7/genética , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Netrinas/metabolismo , Proteínas Ligadas por GPI/metabolismoRESUMO
Graphene derivatives are expected to have a great impact in a wide range of applications, among them as food packaging materials. This is one of the sources of potential human oral exposure to them. However, studies devoted to investigating their putative toxic effects at the intestinal level are underrepresented in the scientific literature. Thus, this study aimed to investigate the in vitro toxicity of reduced graphene oxide (rGO) and graphene oxide (GO) in the human intestinal Caco-2 cell line. rGO and GO were firstly characterized and later, cell viability was assessed after exposure to 0-250 µg/mL rGO/GO for 24 and 48 h. Internalization was evidenced for both materials using transmission electron microscopy. A mean effective concentration (24 h) of 176.3 ± 7.6 µg/mL for cytotoxicity was obtained for rGO, whereas GO did not induce any change at the concentration range evaluated. However, both of them altered oxidative stress biomarkers, causing increased reactive oxygen species (ROS) and depletion of the glutathione content (GSH) after exposures up to 24 h. Further studies, particularly with rGO, are required to elucidate their toxicity profile in experimental models relevant for oral exposures.
RESUMO
A biopreservative derived from the fermentation of a dairy byproduct by Enterococcus faecalis UGRA10 strains being developed. This product possesses a strong and wide antibacterial spectrum mainly due to the presence of Enterocin AS-48 in its composition. To assess its potential as food additive, the mutagenicicity and genotoxicity has been assayed by means of the bacterial reverse-mutation assay in Salmonella typhimurium TA97A, TA98, TA100, TA102, TA1535 strains (Ames test, OECD 471, 2020) and the micronucleus test (MN) (OECD 487, 2016) in L5178Y/Tk ± cells. The results in the Ames test after exposure to the byproduct (6.75-100 µg/plate) with absence and presence of the metabolic activation system from rat liver (S9 fraction), revealed not mutagenicity at the conditions tested. For the MN test, the exposition to five enterocin AS-48 concentrations (0.2-1 µg/µl) was tested in the absence and presence of S9 fraction, with no evidence of genotoxicity. Negative results in the mutagenicity and genotoxicity assays point out the good safety profile of the byproduct and support its use as additive. Further toxicological studies are required before its approval and commercial application.
Assuntos
Bacteriocinas/química , Conservantes de Alimentos/química , Conservantes de Alimentos/toxicidade , Animais , Fígado , Testes de Mutagenicidade , Ratos , Salmonella typhimuriumRESUMO
Cylindrospermopsin (CYN) is a cyanotoxicant which occurrence is increasing due to climate change. Cylindrospermopsin is able to exert damage in the organism at several levels, among them, in the nervous system. Moreover, it is important to take into account that it is not usually present isolated in nature, but in combination with some other pollutants, being the case of the pesticide chlorpyrifos (CPF). Thus, the aim of the present work was to assess the effects of the interaction of CYN in combination with CPF in the human neuroblastoma cell line SH-SY5Y by evaluating cytotoxicity and mechanistic endpoints. The mixtures 0.25 + 21, 0.5 + 42, 1 + 84 µg/mL of CYN + CPF based on cytotoxicity results, were evaluated, and the isobologram method detected an antagonistic effect after 24 and 48 h of exposure. Moreover, although no alterations of reactive oxygen species were detected, a significant decrease of glutathione levels was observed after exposure to both, CPF alone and the combination, at all the concentrations and times of exposure assayed. In addition, CYN + CPF caused a marked decrease in the acetylcholinesterase activity, providing similar values to CPF alone. However, these effects were less severe than expected. All these findings, together with the morphological study results, point out that it is important to take into account the interaction of CYN with other pollutants. Further research is required to contribute to the risk assessment of CYN and other contaminants considering more realistic exposure scenarios.
Assuntos
Toxinas Bacterianas/toxicidade , Clorpirifos/toxicidade , Inibidores da Colinesterase/toxicidade , Poluentes Ambientais/toxicidade , Inseticidas/toxicidade , Uracila/análogos & derivados , Alcaloides , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Toxinas de Cianobactérias , Glutationa/metabolismo , Humanos , Uracila/toxicidadeRESUMO
TetraSOD® is a powder of the lyophilized biomass of Tetraselmis chuii strain CCFM03, a marine microalga with a history of use as feed in the aquaculture industry. Recently, algae including T. chuii have been investigated for their potential use in human food. However, published toxicology studies addressing the safety of T. chuii as a food ingredient are not available. To address this issue, the toxicity of TetraSOD® was evaluated using a 90-day oral toxicology study in rats following the Organisation for Economic Co-operation and Development (OECD) test guideline 408. No treatment-related mortality or clinical signs were noted with TetraSOD® at doses of 625, 1667, or 2500â¯mg/kg/day. Additionally, no adverse effects on haematology, blood biochemistry, organ weights, gross or histopathology were observed. The Non Observed Adverse Effect Level (NOAEL) for TetraSOD® is greater than the highest tested dose of 2500â¯mg/kg/day.
Assuntos
Biomassa , Alimentos/toxicidade , Microalgas , Animais , Clorófitas , Feminino , Liofilização , Masculino , Nível de Efeito Adverso não Observado , Ratos Sprague-Dawley , Testes de Toxicidade SubcrônicaRESUMO
Microcystins (MCs) and cylindrospermopsin (CYN) are among the most frequent toxins produced by cyanobacteria. These toxic secondary metabolites are classified as hepatotoxins and cytotoxin, respectively. Furthermore, both may present the ability to induce damage to the nervous system. In this sense, there are many studies manifesting the potential of MCs to cause neurotoxicity both in vitro and in vivo, due to their probable capacity to cross the blood-brain-barrier through organic anion transporting polypeptides. Moreover, the presence of MCs has been detected in brain of several experimental models. Among the neurological effects, histopathological brain changes, deregulation of biochemical parameters in brain (production of oxidative stress and inhibition of protein phosphatases) and behavioral alterations have been described. It is noteworthy that minority variants such as MC-LF and -LW have demonstrated to exert higher neurotoxic effects compared to the most studied congener, MC-LR. By contrast, the available studies concerning CYN-neurotoxic effects are very scarce, mostly showing inflammation and apoptosis in neural murine cell lines, oxidative stress, and alteration of the acetylcholinesterase activity in vivo. However, more studies are required in order to clarify the neurotoxic potential of both toxins, as well as their possible contribution to neurodegenerative diseases.
Assuntos
Toxinas Bacterianas/toxicidade , Microcistinas/toxicidade , Sistema Nervoso/efeitos dos fármacos , Uracila/análogos & derivados , Alcaloides , Apoptose , Encéfalo , Cianobactérias , Toxinas de Cianobactérias , Estresse Oxidativo , Uracila/toxicidadeRESUMO
Microcystin-LR (MC-LR) and Cylindrospermopsin (CYN) are produced by cyanobacteria. Although being considered as a hepatotoxin and a cytotoxin, respectively, different studies have revealed neurotoxic properties for both of them. The aim of the present work was to study their cytotoxic effects, alone and in combination, in the SH-SY5Y cell line. In addition, toxicity mechanisms such as oxidative stress and acetylcholinesterase (AChE) activity, and morphological studies were carried out. Results showed a cytotoxic response of the cells after their exposure to 0-100⯵g/mL of MC-LR or 0-10⯵g/mL CYN in both differentiated and undifferentiated cells. Thus, CYN resulted to be more toxic than MC-LR. Respect to their combination, a higher cytotoxic effect than the toxins alone in the case of undifferentiated cells, and almost a similar response to the presented by MC-LR in differentiated cells were observed. However, after analyzing this data with the isobolograms method, an antagonistic effect was mainly obtained. The oxidative stress study only showed an affectation of glutathione levels at the highest concentrations assayed of MC-LR and the combination in the undifferentiated cells. A significant increase in the AChE activity was observed after exposure to MC-LR in undifferentiated cells, and after exposure to the combination of both cyanotoxins on differentiated cells. However, CYN decreased the AChE activity only on differentiated cultures. Finally, the morphological study revealed different signs of cellular affectation, with apoptotic processes at all the concentrations assayed. Therefore, both cyanotoxins isolated and in combination, have demonstrated to cause neurotoxic effects in the SH-SY5Y cell line.
Assuntos
Toxinas Bacterianas/toxicidade , Microcistinas/toxicidade , Neurotoxinas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Uracila/análogos & derivados , Acetilcolinesterase/metabolismo , Alcaloides , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Toxinas de Cianobactérias , Antagonismo de Drogas , Combinação de Medicamentos , Humanos , Toxinas Marinhas , Neuroblastoma/tratamento farmacológico , Uracila/toxicidadeRESUMO
Compound-specific isotope analysis (CSIA) usually requires preparative steps (pretreatments, extraction, derivatization) to get amenable chromatographic analytes from bulk geological, biological or synthetic materials. Analytical pyrolysis (Py-GC/MS) can help to overcome such sample manipulation. This communication describe the results obtained by hyphenating analytical pyrolysis (Py-GC) with carbon isotope-ratio mass spectrometry (IRMS) for the analysis of a polylactic acid (PLA) a based bio-plastic extruded with variable quantities of a natural plant extract or oregano essential oil. The chemical structural information of pyrolysates was first determined by conventional analytical pyrolysis and the measure of δ13C in specific compounds was done by coupling a pyrolysis unit to a gas chromatograph connected to a continuous flow IRMS unit (Py-GC-C-IRMS). Using this Py-CSIA device it was possible to trace natural additives with depleted δ13C values produced by C3 photosystem vegetation (cymene: -26.7±2.52; terpinene: -27.1±0.13 and carvacrol: -27.5±1.80 from oregano and two unknown structures: -23.3±3.32 and -24.4±1.70 and butyl valerate: -24.1±3.55 from Allium spp.), within the naturally isotopically enriched bio-plastic backbone derived from corn (C4 vegetation) starch (cyclopentanones: -14.2±2.11; lactide enantiomers: -9.2±1.56 and larger polymeric units: -17.2±1.71). This is the first application of Py-CSIA to characterize a bio-plastic and is shown as a promising tool to study such materials, providing not only a fingerprinting, but also valuable information about the origin of the materials, allowing the traceability of additives and minimizing sample preparation.
Assuntos
Técnicas de Química Analítica/métodos , Embalagem de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Poliésteres/química , Isótopos de Carbono/análise , Cimenos , Monoterpenos/análise , Óleos Voláteis/análise , Extratos Vegetais/análise , Polímeros/químicaRESUMO
Oregano essential oil (Origanum vulgare L. virens) (OEO) is being used in the food industry due to its useful properties to develop new active packaging systems. In this concern, the safety assessment of this natural extract is of great interest before being commercialized. The European Food Safety Authority requests different in vivo assays to ensure the safety of food contact materials. One of these studies is a 90 days repeated-dose oral assay in rodents. In the present work, 40 male and 40 female Wistar rats were orally exposed to 50, 100 and 200 mg/kg body weight (b.w.) OEO during 90 days following the OECD guideline 408. Data revealed no mortality and no treatment-related adverse effects of the OEO in food/water consumption, body weight, haematology, biochemistry, necropsy, organ weight and histopathology. These findings suggest that the oral no-observed-adverse-effect level (NOAEL) of this OEO is 200 mg/kg b.w. in Wistar rats, the highest dose tested. In conclusion, the use of this OEO in food packaging appears to be safe based on the lack of toxicity during the subchronic study at doses 330-fold higher than those expected to be in contact consumers in the worst scenario of exposure.
Assuntos
Óleos Voláteis/toxicidade , Origanum/química , Testes de Toxicidade Subcrônica/métodos , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Feminino , Masculino , Nível de Efeito Adverso não Observado , Óleos Voláteis/administração & dosagem , Ratos , Ratos WistarRESUMO
Consumers' concerns about the environment and health have led to the development of new food packaging materials avoiding petroleum-based matrices and synthetic additives. The present study has developed polylactic acid (PLA) films containing different concentrations of essential oil from Origanum vulgare L. virens (OEO). The effectiveness of this new active packaging was checked for use in ready-to-eat salads. A plasticising effect was observed when OEO was incorporated in PLA films. The rest of the mechanical and physical properties of developed films did not show much change when OEO was included in the film. An antioxidant effect was recorded only for films containing the highest percentages of the active agent (5% and 10%). In addition, films exhibited in vitro antibacterial activity against Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Enterococcus faecalis and Staphylococcus carnosus. Moreover, in ready-to-eat salads, antimicrobial activity was only observed against yeast and moulds, where 5% and 10% of OEO was the most effective.
Assuntos
Antibacterianos/farmacologia , Antioxidantes/farmacologia , Embalagem de Alimentos , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Origanum/química , Poliésteres/química , Antibacterianos/química , Antioxidantes/química , Enterococcus faecalis/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Poliésteres/farmacologia , Staphylococcus/efeitos dos fármacos , Yersinia enterocolitica/efeitos dos fármacosRESUMO
Proallium AP(®) is a commercial Allium extract intended to be used in active food packaging as the antibacterial and antioxidant effects of some organosulfur compounds are well known. However, there is little information on its toxicity and the Scientific Committee on Food (UE) requires the safety assessment of substances used in food contact materials. Thus, the aim of this study was to conduct for the first time a subchronic oral toxicity study of Proallium AP(®) with groups of 10 males and 10 females Sprague-Dawley rats fed a diet containing 0, 25, 100, 400 mg/kg/d for 90 days. No treatment-related clinical signs or mortality were noted. Besides, no treatment-related effects with regard to any of the toxicological biomarkers considered were observed, including biochemical, haematological and histopathology parameters. In conclusion, the non-observed-adverse-effect-level (NOAEL) for Proallium AP(®) in rats was determined to be a dietary dose of 400 mg/kg/d under the present experimental conditions, a value 500-fold higher than the exposure derived from its potential use in active packaging.
Assuntos
Allium/química , Extratos Vegetais/toxicidade , Animais , Relação Dose-Resposta a Droga , Feminino , Embalagem de Alimentos , Masculino , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Ratos , Ratos Sprague-DawleyRESUMO
Essential oils from onion (Allium cepa L.), garlic (Allium sativum L.), and their main components, such as propyl thiosulfinate oxide (PTSO) are being intended for active packaging with the purpose of maintaining and extending food product quality and shelf life. The present work aims to assess for the first time the potential mutagenicity/genotoxicity of PTSO (0-50 µM) using the following battery of genotoxicity tests: (1) the bacterial reverse-mutation assay in Salmonella typhimurium (Ames test, OECD 471); (2) the micronucleus test (OECD 487) (MN) and (3) the mouse lymphoma thymidine-kinase assay (OECD 476) (MLA) on L5178YTk(+/-), cells; and (4) the comet assay (with and without Endo III and FPG enzymes) on Caco-2 cells. The results revealed that PTSO was not mutagenic in the Ames test, however it was mutagenic in the MLA assay after 24 h of treatment (2.5-20 µM). The parent compound did not induce MN on mammalian cells; however, its metabolites (in the presence S9) produced positive results (from 15 µM). Data from the comet assay indicated that PTSO did not induce DNA breaks or oxidative DNA damage. Further in vivo genotoxicity tests are needed to confirm its safety before it is used as active additive in food packaging.
Assuntos
Allium/química , Extratos Vegetais/farmacologia , Ácidos Sulfínicos/toxicidade , Animais , Células CACO-2 , Linhagem Celular , Ensaio Cometa , Embalagem de Alimentos , Humanos , Camundongos , Testes para Micronúcleos , Mutação , Extratos Vegetais/química , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Ácidos Sulfínicos/químicaRESUMO
Cyanobacteria are able to produce several metabolites that have toxic effects on humans and animals. Among these cyanotoxins, the hepatotoxic microcystins (MC) occur frequently. The intracellular MC content produced by two strains of Microcystis aeruginosa, PCC7806 and PCC7820, and its production kinetics during the culture time were studied in order to elucidate the conditions that favour the growth and proliferation of these toxic strains. Intracellular MC concentrations measured by liquid chromatography (LC) coupled to electrospray ionization mass spectrometer (MS) were compared with those obtained by enzyme-linked immunosorbent assay (ELISA) anti-Adda and protein phosphatase 2A (PP2A) inhibition assays. It has been demonstrated there are discrepancies in the quantification of MC content when comparing ELISA and LC-MS results. However, a good correlation has been obtained between PP2A inhibition assay and LC-MS. Three MC were identified using LC-MS in the PCC7806 strain: MC-LR, demethylated MC-LR and a new variant detected for the first time in this strain, [L-MeSer(7)] MC-LR. In PCC7820, MC-LR, D-Asp(3)-MCLR, Dglu(OCH3)-MCLR, MC-LY, MC-LW and MC-LF were identificated. The major one was MC-LR in both strains, representing 81 and 79% of total MC, respectively. The total MC content in M. aeruginosa PCC7820 was almost three-fold higher than in PCC7806 extracts.
Assuntos
Microcistinas/metabolismo , Microcystis/crescimento & desenvolvimento , Microcystis/metabolismo , Bioensaio/métodos , Calcineurina/análise , Técnicas de Cultura de Células , Cromatografia Líquida , Ensaio de Imunoadsorção Enzimática , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Cylindrospermopsin (CYN) is a cytotoxic polyketide-derived alkaloid produced by several freshwater cyanobacterial species. It is now considered the second most studied cyanotoxin worldwide. Among the toxic mechanisms suggested for CYN pathogenicity are inhibition of protein and glutathione synthesis, genotoxicity by DNA fragmentation, and oxidative stress. The study of depuration of cyanobacterial toxins by aquatic organisms, particularly by fish, is important for fish economy and public health, but in the case of CYN is practically nonexistent. In this work, we investigated the efficiency of two distinct depuration periods, 3 or 7d, in a clean environment, as a mean of restoring the levels of several oxidative stress biomarkers in tilapia (Oreochromis niloticus) subchronically exposed to CYN by immersion in an Aphanizomenon ovalisporum culture (by adding 10 µg CYN/L every two days during 14 d). Lipid peroxidation (LPO) and DNA oxidation returned to normal values after 7d of depuration, whereas the time needed for restoring of the oxidatively damaged proteins was longer. Superoxide dismutase (SOD) and gamma-glutamyl-cysteine-synthetase (γ-GCS) activities recovered after just 3d of depuration, while catalase (CAT) activity needed up to 7d to return to control values. Ratio of reduced glutathione to oxidized glutathione (GSH/GSSG) returned to control levels after 7d of depuration in both organs. These results validate the depuration process as a very effective practice for detoxification in fish contaminated with these toxins.
Assuntos
Biomarcadores/análise , Ciclídeos/fisiologia , Cianobactérias/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Uracila/análogos & derivados , Poluentes Químicos da Água/toxicidade , Alcaloides , Animais , Toxinas Bacterianas , Catalase/metabolismo , Cianobactérias/química , Toxinas de Cianobactérias , Ativação Enzimática/efeitos dos fármacos , Glutamato-Cisteína Ligase/metabolismo , Rim/química , Rim/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/química , Fígado/efeitos dos fármacos , Oxirredução , Superóxido Dismutase/metabolismo , Fatores de Tempo , Uracila/análise , Uracila/toxicidade , Água/químicaRESUMO
Cylindrospermopsin (CYN) is a cytotoxic cyanotoxin produced by several cyanobacteria species. It has been demonstrated that CYN is a potent protein and glutathione synthesis inhibitor, and induces genotoxicity and oxidative stress. The present study investigated the protective role of two different doses of N-Acetylcysteine (NAC) (22 and 45 mg/fish/day) against the pathological changes induced in tilapia (Oreochromis niloticus) orally exposed to a single dose of pure CYN or CYN from an Aphanizomenon ovalisporum CYN-producer strain (200 µg/kg of CYN in both cases). Moreover, an immunohistochemical (IHC) analysis was carried out in order to elucidate the CYN distribution in exposed fish. The histological findings were more pronounced when fish were intoxicated with CYN from the cyanobacterial strain, being liver and kidney the main targets for CYN toxicity. NAC pre-treatment was effective reducing the damage induced by CYN, especially at the highest dose employed (45 mg/fish/day), with a total prevention in all organs. The IHC analysis showed that CYN-antigen appeared mainly in the liver and gastrointestinal tract, although it was also present in kidney and gills. In this case, the immunopositive results were more abundant in those fish exposed to pure CYN. NAC reduced the number of immunopositive cases in a dose-dependent way. Therefore, NAC can be considered a useful chemoprotectant in the prophylaxis and treatment of CYN-related intoxications in fish.
Assuntos
Acetilcisteína/farmacologia , Aphanizomenon/química , Ciclídeos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Uracila/análogos & derivados , Alcaloides , Animais , Toxinas Bacterianas , Toxinas de Cianobactérias , Relação Dose-Resposta a Droga , Trato Gastrointestinal/efeitos dos fármacos , Imuno-Histoquímica/veterinária , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Uracila/toxicidadeRESUMO
Cylindrospermopsin (CYN) is one of the most important cyanotoxins in terms of both human health and environmental quality and is produced by several different species of cyanobacteria, including Aphanizomenon ovalisporum. The principal mechanisms of action of CYN involve inhibition of protein and glutathione synthesis. In addition, CYN-mediated genotoxicity results from DNA fragmentation. The results of both in vivo and in vitro studies suggest that oxidative stress also plays a significant role in CYN pathogenesis in fish. We investigated the protective effects of l-carnitine (LC) pre-treatment on A. ovalisporum-induced oxidative stress in cells containing CYN and deoxy-CYN, or pure standard CYN, in tilapia (Oreochromis niloticus) that had been acutely exposed via oral administration. Various oxidative stress markers, including lipid peroxidation (LPO), protein oxidation, DNA oxidation, and the ratio of reduced glutathione to oxidised glutathione (GSH/GSSG), and the activities of NADPH oxidase, superoxide dismutase (SOD), catalase (CAT), and gamma-glutamyl-cysteine synthetase (γ-GCS), were evaluated in the livers and kidneys of fish in the absence and presence of 400 or 880mgLC/kgfish/day during a 21 day period prior to CYN-intoxication. The results of our study demonstrated for the first time the beneficial antioxidant effects of LC dietary supplementation on oxidative stress status in fish. No pro-oxidant effects were detected at any of the LC doses assayed, suggesting that LC is a chemoprotectant that reduces hepatic and renal oxidative stress and may be effective when used for the prophylaxis and treatment of CYN-related intoxication in fish.
Assuntos
Antioxidantes/metabolismo , Carnitina/farmacologia , Ciclídeos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Uracila/análogos & derivados , Alcaloides , Animais , Toxinas Bacterianas , Biomarcadores/metabolismo , Cromatografia Líquida , Toxinas de Cianobactérias , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Oxirredução , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Uracila/toxicidadeRESUMO
Cylindrospermopsin (CYN) is a potent cyanobacterial cytotoxin produced by certain freshwater cyanobacteria. Structurally, it is an alkaloid with a tricyclic guanidine moiety combined with hydroxymethyluracil. It has proved to be a potent inhibitor of protein synthesis, and to deplete hepatic glutathione. Recently, some studies have shown that CYN produces changes in some oxidative stress biomarkers in fish acutely exposed to pure CYN by oral and intraperitoneal (i.p.) routes. In the present study tilapia (Oreochromis niloticus) were exposed by immersion to lyophilized Aphanizomenon ovalisporum cells added to the aquaria using two concentration levels, 10 or 100 µg CYN L(-1), during two different exposure times: 7 and 14 d. Fish were sacrificed and liver and kidney were extracted. The oxidative status of fish was evaluated by analyzing in both organs the following biomarkers: lipid peroxidation (LPO), protein oxidation, DNA oxidation, reduced-oxidized glutathione ratio (GSH/GSSG), and changes in the activity of Glutathione-S-transferase (GST), Glutathione Peroxidase (GPx), Superoxide dismutase (SOD), Catalase (CAT), and γ-Glutamyl-cysteine synthetase (GCS). In general, major changes were observed in tilapia treated with 100 µg CYN L(-1) after 14 d of exposure. However, some endpoints were altered at the lowest concentration assayed only after 7d of exposure, such as DNA oxidation and γ-GCS in kidney, and CAT and GSH/GSSG decrease in the liver and kidney. The kidney was the most affected organ. These findings confirm that the oxidative stress play a role in the pathogenicity induced by CYN in this fish species, and the results obtained could be useful for future ecotoxicological risks assessment studies, for the protection of fish and aquatic ecosystems. To our knowledge this is the first study dealing with the oxidative stress changes induced by cyanobacterial cells containing CYN and its derivative deoxy-CYN on fish exposed sub-chronically under laboratory conditions.
Assuntos
Aphanizomenon/metabolismo , Ciclídeos/metabolismo , Eutrofização , Estresse Oxidativo/efeitos dos fármacos , Uracila/análogos & derivados , Alcaloides/metabolismo , Alcaloides/toxicidade , Animais , Toxinas Bacterianas , Catalase/metabolismo , Toxinas de Cianobactérias , DNA/metabolismo , Proteínas de Peixes/metabolismo , Glutamato-Cisteína Ligase/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Uracila/metabolismo , Uracila/toxicidadeRESUMO
Mangoes of uniform genetics (Lippens variety) cultivated in the Gomera Island (Canary Islands) by conventional and organic farming were used to analyze the mineral content in order to differentiate crops cultivated in the same geographic area by the cultivation practices. Farming differences as well as soil differences may be reflected in the mineral content of the mangoes cultivated in these extensions. Concentration metal profiles consisting of the content of Ca, Co, Cu, Fe, K, Mg, Mn, Na, Ni and Zn in mangoes were obtained by using atomic absorption spectrometry (AAS). Pattern recognition classification procedures were applied for discriminating purposes. Linear discriminant analysis (LDA) allows to a classification performance of about 73% and support vector machines (SVM) found up to a 93% of prediction ability. The classification success when applying support vector machines techniques is due to their ability for modeling non-linear class boundaries.
Assuntos
Mangifera/química , Mangifera/crescimento & desenvolvimento , Minerais/análise , Agricultura Orgânica , Máquina de Vetores de Suporte , Análise DiscriminanteRESUMO
Reduced glutathione (GSH) protects cells against injury by oxidative stress and maintains a range of vital functions. In vitro cell cultures have been used as experimental models to study the role of GSH in chemical toxicity in mammals; however, this approach has been rarely used with fish cells to date. The present study aimed to evaluate sensitivity and specificity of three fluorescent dyes for measuring pro-oxidant-induced changes of GSH contents in fish cell lines: monochlorobimane (mBCl), 5-chloromethylfluorescein diacetate (CMFDA) and 7-amino-4-chloromethylcoumarin (CMAC-blue). Two cell lines were studied, the EPC line established from a skin tumour of carp Cyprinus carpio, and BF-2 cells established from fins of bluegill sunfish Lepomis macrochirus. The cells were exposed for 6 and 24 h to low cytotoxic concentrations of pro-oxidants including hydrogen peroxide, paraquat (PQ), copper and the GSH synthesis inhibitor, L-buthionine-SR-sulfoximine (BSO). The results indicate moderate differences in the GSH response between EPC and BF-2 cells, but distinct differences in the magnitude of the GSH response for the four pro-oxidants. Further, the choice of GSH dye can critically affect the results, with CMFDA appearing to be less specific for GSH than mBCl and CMAC-blue.
Assuntos
Antioxidantes/metabolismo , Células Epiteliais/efeitos dos fármacos , Corantes Fluorescentes/metabolismo , Glutationa/metabolismo , Oxidantes/toxicidade , Animais , Antioxidantes/análise , Butionina Sulfoximina/farmacologia , Carpas , Linhagem Celular Tumoral , Sobrevivência Celular , Sulfato de Cobre/toxicidade , Cumarínicos/química , Cumarínicos/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Fluoresceínas/química , Fluoresceínas/metabolismo , Corantes Fluorescentes/química , Glutationa/análise , Peróxido de Hidrogênio/toxicidade , Paraquat/toxicidade , Perciformes , Valor Preditivo dos Testes , Pirazóis/química , Pirazóis/metabolismoRESUMO
The toxicity assessment of chemicals is one of the main issues in the current policies in order to protect the health of the environment and human beings. Food and cosmetic additives have been extensively studied in relation to their toxicity to humans, but data about their ecotoxicological effects are scarce. The aim of this study was to evaluate the toxic effects of the additive 6-methylcoumarine in the aquatic milieu using a test battery comprising experimental model systems from different trophic levels. The inhibition of bioluminiscence was studied in the bacteria Vibrio fischeri (decomposer), the inhibition of growth was evaluated in the alga Chlorella vulgaris (producer) and immobilization was studied in the cladoceran Daphnia magna (first consumer). Finally, several end points were evaluated in the RTG-2 salmonid fish cell line, including neutral red uptake, protein content, methylthiazol tetrazolium salt metabolization, glucose-6-phosphate dehydrogenase activity, lactate dehydrogenase activity and leakage, and morphology. The sensitivity of the test systems employed was as follows: V. fischeri > D. magna > C. vulgaris > RTG-2 cell line. The results show that 6-methylcoumarine is not expected to produce acute toxic effects on the aquatic biota. However, chronic and synergistic effects with other chemicals cannot be excluded and should be further investigated.