RESUMO
Nicotine binds to nicotinic acetylcholine receptors (nAChRs) that are overexpressed in different cancer cells, promoting tumor growth and resistance to chemotherapy. In this study, we aimed to investigate the potential of APS7-2 and APS8-2, synthetic analogs of a marine sponge toxin, to inhibit nicotine-mediated effects on A549 human lung cancer cells. Our electrophysiological measurements confirmed that APS7-2 and APS8-2 act as α7 nAChR antagonists. APS8-2 showed no cytotoxicity in A549 cells, while APS7-2 showed concentration-dependent cytotoxicity in A549 cells. The different cytotoxic responses of APS7-2 and APS8-2 emphasize the importance of the chemical structure in determining their cytotoxicity on cancer cells. Nicotine-mediated effects include increased cell viability and proliferation, elevated intracellular calcium levels, and reduced cisplatin-induced cytotoxicity and reactive oxygen species production (ROS) in A549 cells. These effects of nicotine were effectively attenuated by APS8-2, whereas APS7-2 was less effective. Our results suggest that APS8-2 is a promising new therapeutic agent in the chemotherapy of lung cancer.
Assuntos
Antineoplásicos , Sobrevivência Celular , Neoplasias Pulmonares , Nicotina , Espécies Reativas de Oxigênio , Receptor Nicotínico de Acetilcolina alfa7 , Humanos , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Células A549 , Nicotina/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Espécies Reativas de Oxigênio/metabolismo , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Animais , Antagonistas Nicotínicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Cálcio/metabolismo , Poríferos/químicaRESUMO
Microplastic (MP) contamination in the aquatic environment is a cause of concern worldwide since MP can be taken up by different organisms, altering different biological functions. In particular, evidence is accumulating that MP can affect the relationship between the host and its associated microbial communities (the microbiome), with potentially negative health consequences. Synthetic microfibers (MFs) represent one of the main MPs in the marine environment, which can be accumulated by filter-feeding invertebrates, such as bivalves, with consequent negative effects and transfer through the food chain. In the mussel Mytilus galloprovincialis, polyethylene terephthalate (PET) MFs, with a size distribution resembling that of an MF released from textile washing, have been previously shown to induce multiple stress responses. In this work, in the same experimental conditions, the effects of exposure to PET-MF (96 h, 10, and 100 µg/L) on mussel hemolymph microbiome were evaluated by 16S rRNA gene amplification and sequencing. The results show that PET-MF affects the composition of bacterial communities at the phylum, family and genus level, with stronger effects at the lowest concentration tested. The relationship between MF-induced changes in hemolymph microbial communities and responses observed at the whole organism level are discussed.
Assuntos
Hemolinfa , Microbiota , Mytilus , RNA Ribossômico 16S , Animais , Mytilus/microbiologia , Hemolinfa/metabolismo , Hemolinfa/microbiologia , RNA Ribossômico 16S/genética , Poliésteres , Poluentes Químicos da Água/toxicidade , Microplásticos/toxicidade , Polietilenotereftalatos , Bactérias/classificação , Bactérias/genéticaRESUMO
Genotoxicity testing for nanomaterials remains challenging as standard testing approaches require some adaptation, and further development of nano-specific OECD Test Guidelines (TGs) and Guidance Documents (GDs) are needed. However, the field of genotoxicology continues to progress and new approach methodologies (NAMs) are being developed that could provide relevant information on the range of mechanisms of genotoxic action that may be imparted by nanomaterials. There is a recognition of the need for implementation of new and/or adapted OECD TGs, new OECD GDs, and utilization of NAMs within a genotoxicity testing framework for nanomaterials. As such, the requirements to apply new experimental approaches and data for genotoxicity assessment of nanomaterials in a regulatory context is neither clear, nor used in practice. Thus, an international workshop with representatives from regulatory agencies, industry, government, and academic scientists was convened to discuss these issues. The expert discussion highlighted the current deficiencies that exist in standard testing approaches within exposure regimes, insufficient physicochemical characterization, lack of demonstration of cell or tissue uptake and internalization, and limitations in the coverage of genotoxic modes of action. Regarding the latter aspect, a consensus was reached on the importance of using NAMs to support the genotoxicity assessment of nanomaterials. Also highlighted was the need for close engagement between scientists and regulators to (i) provide clarity on the regulatory needs, (ii) improve the acceptance and use of NAM-generated data, and (iii) define how NAMs may be used as part of weight of evidence approaches for use in regulatory risk assessments.
Assuntos
Nanoestruturas , Organização para a Cooperação e Desenvolvimento Econômico , Testes de Mutagenicidade/métodos , Nanoestruturas/toxicidade , Nanoestruturas/química , Medição de RiscoRESUMO
The preparation of autologous platelet and extracellular vesicle-rich plasma (PVRP) has been explored in many medical fields with the aim to benefit from its healing potential. In parallel, efforts are being invested to understand the function and dynamics of PVRP that is complex in its composition and interactions. Some clinical evidence reveals beneficial effects of PVRP, while some report that there were no effects. To optimize the preparation methods, functions and mechanisms of PVRP, its constituents should be better understood. With the intention to promote further studies of autologous therapeutic PVRP, we performed a review on some topics regarding PVRP composition, harvesting, assessment and preservation, and also on clinical experience following PVRP application in humans and animals. Besides the acknowledged actions of platelets, leukocytes and different molecules, we focus on extracellular vesicles that were found abundant in PVRP.
Assuntos
Plasma Rico em Plaquetas , Humanos , Animais , Plaquetas , Cicatrização , LeucócitosRESUMO
Secondary salinization of freshwater is becoming a growing environmental problem. Currently, there is few data available on the effects of salinisation on subterranean crustaceans that are vital for the maintenance of groundwater ecosystem functioning. In this study, the sensitivity of subterranean Niphargus amphipods to NaCl was investigated. We expected that cave-dwelling species would be more sensitive as surface-subterranean boundary species. Eight ecologically different Niphargus species were tested: four live at the boundary between the surface and subterranean ecosystems (N. timavi, N. krameri, N. sphagnicolus, N. spinulifemur), three live in cave streams (N. stygius, N. scopicauda, N. podpecanus), and one species (N. hebereri) lives in anchialine caves and wells. The organisms were exposed to five concentrations of NaCl for 96 h and afterwards the immobility, mortality, and electron transfer system (ETS) activity (a measure for metabolic rate of animals) were evaluated. As expected, the most tolerant species was N. hebereri dwelling in naturally high-salinity habitat. However, contrary to our expectations, the species collected at the surface-subterranean boundary were more sensitive as cave stream species when their immobility and mortality were assessed. Interestingly, the majority of Niphargus tested were more NaCl tolerant as can be deduced from currently available data for subterranean and surface crustaceans. We could not observe a clear trend in ETS activity changes between groups of surface-subterranean boundary and cave streams species after exposure to NaCl stress, but it appears that osmotic stress-induced metabolic rate changes are species-specific. This study shows that amphipods Niphargus can be a valuable subterranean environmental research model and further ecotoxicity research is of interest.
Assuntos
Anfípodes , Animais , Cavernas , Ecossistema , Salinidade , Cloreto de SódioRESUMO
Tetraethyl-orthosilicate (TEOS)-based nanoparticles are most extensively used as a silica-based hemoglobin carrier system. However, TEOS-based nanoparticles induce adverse effects on the hemoglobin structure. Therefore, a heulandite-calcium-based carrier was investigated as a novel silica-based hemoglobin carrier system. The heulandite-calcium mesoporous aluminosilicate particles (MSPs) were fabricated by a patented tribo-mechanical activation process, according to the manufacturer, and its structure was assessed by X-ray diffraction analysis. Upon hemoglobin encapsulation, alternation in the secondary and tertiary structure was observed. The hemoglobin-particle interactions do not cause heme degradation or decreased activity. Once encapsulated inside the particle pores, the hemoglobin shows increased thermal stability, and higher loading capacity per gram of particles (by a factor of >1.4) when compared to TEOS-based nanoparticles. Futhermore, we introduced a PEGlyted lipid bilayer which significantly decreases the premature hemoglobin release and increases the colloidal stability. The newly developed hemoglobin carrier shows no cytotoxicity to human umbilical vein endothelial cells (HUVEC).
Assuntos
Substitutos Sanguíneos , Aluminossilicato de Cálcio , Nanopartículas , Humanos , Silicatos de Alumínio , Cálcio , Células Endoteliais , Hemoglobinas , Nanopartículas/química , Porosidade , Dióxido de Silício/químicaRESUMO
Superparamagnetic iron oxide nanoparticles (SPIONs) have great potential for use in medicine, but they may cause side effects due to oxidative stress. In our study, we investigated the effects of silica-coated SPIONs on endothelial cells and whether oleic acid (OA) can protect the cells from their harmful effects. We used viability assays, flow cytometry, infrared spectroscopy, fluorescence microscopy, and transmission electron microscopy. Our results show that silica-coated SPIONs are internalized by endothelial cells, where they increase the amount of reactive oxygen species (ROS) and cause cell death. Exposure to silica-coated SPIONs induced accumulation of lipid droplets (LD) that was not dependent on diacylglycerol acyltransferase (DGAT)-mediated LD biogenesis, suggesting that silica-coated SPIONs suppress LD degradation. Addition of exogenous OA promoted LD biogenesis and reduced SPION-dependent increases in oxidative stress and cell death. However, exogenous OA protected cells from SPION-induced cell damage even in the presence of DGAT inhibitors, implying that LDs are not required for the protective effect of exogenous OA. The molecular phenotype of the cells determined by Fourier transform infrared spectroscopy confirmed the destructive effect of silica-coated SPIONs and the ameliorative role of OA in the case of oxidative stress. Thus, exogenous OA protects endothelial cells from SPION-induced oxidative stress and cell death independent of its incorporation into triglycerides.
Assuntos
Nanopartículas de Magnetita , Dióxido de Silício , Morte Celular , Células Endoteliais , Nanopartículas Magnéticas de Óxido de Ferro , Nanopartículas de Magnetita/química , Ácido Oleico/farmacologia , Estresse Oxidativo , Dióxido de Silício/farmacologiaRESUMO
This paper proposes a list of specifications (NanoTox metadata list) to be reported about nanotoxicity experiments (metadata) together with resultant data to add toxicological context to reported studies. In areas involving nanomaterials (NMs), existing metadata reporting standards include the reporting of experimental conditions and protocols (MIRIBEL) and material characteristics (MINChar and MIAN), as well as reporting focused on specific experiments (MINBE). NanoCRED is a similarly transparent and structured framework, however, it is developed to guide risk assessors in evaluating the reliability and relevance of NM ecotoxicity studies. There is no reporting standard which would include interpretation of the aims and outcomes of nanotoxicity studies beyond regulatory purposes. The proposed NanoTox metadata reporting checklist is elaborated to extend reporting toward describing nanotoxicological context and thus is a logical complement to technology/material-assay focused reporting checklists. It is further designed to allow for NM toxicity data and knowledge integration, reuse, and communication. Its ultimate goal is to adhere to the basic rules of toxicology when taking a stand on the toxicity of NMs and to limit speculations on safety. As nanotoxicology becomes more interdisciplinary with the advent of new tools and new materials to be tested, reporting standards will contribute to cross-disciplinary communication.
Assuntos
Metadados , Nanoestruturas , Nanoestruturas/toxicidade , Padrões de Referência , Reprodutibilidade dos TestesRESUMO
The effects of a new material based on hydroxyapatite and calcium silicates, named ALBO-MPCA, were investigated on the liver, kidney and spleen. The material was administrated orally for 120 days in an in vivo model in Wistar rats, and untreated animals served as a control. Hematological and biochemical blood parameters were analyzed. Qualitative histological analysis of tissues, change in mitotic activity of cells, and histological characteristics was conducted, as well as quantitative stereological analysis of parenchymal cells, blood sinusoids, and connective tissues. Additionally, the protein expressions of Ki67 and CD68 markers were evaluated. Histological analysis revealed no pathological changes after the tested period. It showed the preservation of the architecture of blood sinusoids and epithelial cells and the presence of mitosis. Additionally, the significantly increased number of the Ki67 in the presence of ALBO-MPCA confirmed the proliferative effect of the material noticed by stereological analysis, while immunoreactive CD68 positive cells did not differ between groups. The study showed non-toxicity of the tested material based on the effects on the hematological, biochemical, and observed histological parameters; in addition, it showed evidence of its biocompatibility. These results could be the basis for further steps toward the application of tested materials in endodontics.
Assuntos
Materiais Biocompatíveis/farmacologia , Compostos de Cálcio/farmacologia , Cimentos Dentários/farmacologia , Durapatita/farmacologia , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Silicatos/farmacologia , Baço/efeitos dos fármacos , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/metabolismo , Antígeno Ki-67/metabolismo , Rim/metabolismo , Fígado/metabolismo , Masculino , Teste de Materiais/métodos , Ratos , Ratos Wistar , Baço/metabolismoRESUMO
The interaction of a living organism with external foreign agents is a central issue for its survival and adaptation to the environment. Nanosafety should be considered within this perspective, and it should be examined that how different organisms interact with engineered nanomaterials (NM) by either mounting a defensive response or by physiologically adapting to them. Herein, the interaction of NM with one of the major biological systems deputed to recognition of and response to foreign challenges, i.e., the immune system, is specifically addressed. The main focus is innate immunity, the only type of immunity in plants, invertebrates, and lower vertebrates, and that coexists with adaptive immunity in higher vertebrates. Because of their presence in the majority of eukaryotic living organisms, innate immune responses can be viewed in a comparative context. In the majority of cases, the interaction of NM with living organisms results in innate immune reactions that eliminate the possible danger with mechanisms that do not lead to damage. While in some cases such interaction may lead to pathological consequences, in some other cases beneficial effects can be identified.
Assuntos
Imunidade Inata , Nanoestruturas , Medição de Risco , Imunidade Adaptativa , Animais , Imunidade Inata/efeitos dos fármacos , Nanoestruturas/toxicidade , Medição de Risco/métodosRESUMO
The majority of bladder cancers in humans are non-muscle-invasive cancers that recur frequently after standard treatment procedures. Mouse models are widely used to develop anti-tumor treatments. The purpose of our work was to establish an orthotopic mouse bladder tumor model and to explore early stages of implantation of cancerous MB49 cells in vivo using various labeling and microscopic techniques. To distinguish cancer cells from normal urothelial cells in mouse urinary bladders, we performed molecular characterization of MB49 cells before intravesical injection experiments. In this new approach we applied internalized metal nanoparticles to unequivocally discriminate cancer cells from normal cells. This method revealed that cancer cells attached to the urothelium or basal lamina within just 1 hour of intravesical injection, whereas small tumors and localized hyperplastic urothelial regions developed within two days. We found that cancer cells initially adhere to normal urothelial cells through filopodia and by focal contacts with basal lamina. This is the first in vivo characterization of intercellular contacts between cancerous and normal urothelial cells in the bladder. Our study yields new data about poorly known early events of tumorigenesis in vivo, which could be helpful for the translation into clinic.
Assuntos
Células Epiteliais/citologia , Transplante de Neoplasias/patologia , Neoplasias da Bexiga Urinária/patologia , Bexiga Urinária/citologia , Animais , Antígeno Carcinoembrionário/genética , Carcinogênese , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Células Tumorais Cultivadas , Neoplasias da Bexiga Urinária/genéticaRESUMO
The present work aims to study the effects that acute exposure to low concentrations of silver nanoparticles (AgNPs) cause in digestive glands of terrestrial isopods (Porcellio scaber). The experiments were designed to integrate different analytical techniques, such as transmission electron microscopy, atomic absorption spectroscopy, proton induced X-ray emission, and Fourier transform IR imaging (FTIRI), in order to gain a comprehensive insight into the process from the AgNPs' synthesis to their interaction with biological tissues in vivo. To this aim, terrestrial isopods were fed with AgNPs having different shapes, sizes, and concentrations. For all the tested conditions, no toxicity at the whole organism level was observed after 14 days of exposure. However, FTIRI showed that AgNPs caused detectable local changes in proteins, lipids, nucleic acids and carbohydrates at the tissue level, to an extent dependent on the interplay of the AgNPs' properties: shape, size, concentration and dissolution of ions from them.
Assuntos
Isópodes/química , Nanopartículas Metálicas/química , Prata/química , Animais , Feminino , Mucosa Intestinal/química , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Isópodes/efeitos dos fármacos , Isópodes/metabolismo , Masculino , Nanopartículas Metálicas/administração & dosagem , Microscopia , Tamanho da Partícula , Análise de Componente Principal , Solubilidade , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The use of titanium suboxides, known as Magnéli phase TiOx, is expected to increase in the near future due to their desirable properties. In order to use Magnéli phase TiOx nanoparticles safely, it is necessary to know how nanoparticles interact with biological systems. In this study, the cytotoxicity of three different Magnéli TiOx nanoparticles was evaluated using human lung A549 cells and the results were compared with hazard data on two different TiO2 nanoparticles whose biological interactions have already been extensively studied. After A549 cells were exposed to nanoparticles, the metabolic activity was measured by the Resazurin assay, the amount of cellular proteins was measured by the Coomassie Blue assay, and lysosomal integrity was measured by the Neutral Red Uptake assay. In order to investigate possible modes of particle actions, intracellular Ca2+ level, reactive oxygen species (ROS) production, and photo-oxidative disruptions of lysosomal membranes were assessed. All experiments were performed in serum-containing and in serum-deprived cell culture mediums. In addition, the photocatalytic activity of Magnéli TiOx and TiO2 nanoparticles was measured. The results show that Magnéli TiOx nanoparticles increase intracellular Ca2+ but not ROS levels. In contrast, TiO2 nanoparticles increase ROS levels, resulting in a higher cytotoxicity. Although Magnéli TiOx nanoparticles showed a lower UV-A photocatalytic activity, the photo-stability of the lysosomal membranes was decreased by a greater extent, possibly due to particle accumulation inside lysosomes. We provide evidence that Magnéli TiOx nanoparticles have lower overall biological activity when compared with the two TiO2 formulations. However, some unique cellular interactions were detected and should be further studied in line with possible Magnéli TiOx application. We conclude that Magnéli phase nanoparticles could be considered as low toxic material same as other forms of titanium oxide particles.
Assuntos
Pulmão/patologia , Nanopartículas/toxicidade , Titânio/toxicidade , Células A549 , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Humanos , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Espaço Intracelular/metabolismo , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Nanopartículas/ultraestrutura , Oxirredução , Espécies Reativas de Oxigênio/metabolismoRESUMO
One of the most widely used aquatic standarized tests for the toxicity screening of chemicals is the acute toxicity test with the freshwater crustacean Daphnia magna, which has also been applied in the toxicity screening of manufactured nanoparticles (NPs). However, in the case of non-soluble NPs most of the results of this test have showed no effect. The aim of the work presented here was to modify the standardized test by the least possible extent to make it more sensitive for non-soluble particles. The standard acute immobilisation assay with daphnids was modified by prolonging the exposure period and by measuring additional endpoints. Daphnids were exposed to TiO2 NPs in a standard acute test (48h of exposure), a standard acute test (48h of exposure) followed by 24h recovery period in clean medium or a prolonged exposure in the NPs solutions totaling 72h. Together with immobility, the adsorption of NPs to body surfaces was also observed as an alternative measure of the NPs effects. Our results showed almost no effect of TiO2 NPs on D. magna after the 48h standard acute test, while immobility was increased when the exposure period to TiO2 NPs was prolonged from 48h to 72h. Even when daphnids were transferred to clean medium for additional 24h after 48h of exposure to TiO2 NPs the immobility increased. We conclude that by transferring the daphnids to clean medium at the end of the 48h exposure to TiO2 NPs, the delayed effects of the tested material can be seen. This methodological step could improve the sensitivity of D. magna test as a model in nanomaterial environmental risk assessment.
Assuntos
Daphnia/efeitos dos fármacos , Nanopartículas/toxicidade , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Adsorção , Animais , Bioensaio , Água Doce/química , Nanopartículas/química , Solubilidade , Propriedades de Superfície , Fatores de Tempo , Testes de Toxicidade Aguda/métodos , Poluentes Químicos da Água/química , Óxido de Zinco/químicaRESUMO
Materials with controllable multifunctional abilities for optical imaging (OI) and magnetic resonant imaging (MRI) that also can be used in photodynamic therapy are very interesting for future applications. Mesoporous TiO2 sub-micrometer particles are doped with gadolinium to improve photoluminescence functionality and spin relaxation for MRI, with the added benefit of enhanced generation of reactive oxygen species (ROS). The Gd-doped TiO2 exhibits red emission at 637 nm that is beneficial for OI and significantly improves MRI relaxation times, with a beneficial decrease in spin-lattice and spin-spin relaxation times. Density functional theory calculations show that Gd3+ ions introduce impurity energy levels inside the bandgap of anatase TiO2 , and also create dipoles that are beneficial for charge separation and decreased electron-hole recombination in the doped lattice. The Gd-doped TiO2 nanobeads (NBs) show enhanced ability for ROS monitored via ⢠OH radical photogeneration, in comparison with undoped TiO2 nanobeads and TiO2 P25, for Gd-doping up to 10%. Cellular internalization and biocompatibility of TiO2 @xGd NBs are tested in vitro on MG-63 human osteosarcoma cells, showing full biocompatibility. After photoactivation of the particles, anticancer trace by means of ROS photogeneration is observed just after 3 min irradiation.
Assuntos
Gadolínio/química , Luminescência , Nanopartículas/química , Neoplasias/diagnóstico , Neoplasias/terapia , Espécies Reativas de Oxigênio/metabolismo , Marcadores de Spin , Titânio/química , Catálise , Linhagem Celular Tumoral , Sobrevivência Celular , Teoria da Densidade Funcional , Humanos , Radical Hidroxila/química , Imageamento por Ressonância Magnética , Nanopartículas/ultraestrutura , Imagem Óptica , Porosidade , Temperatura , Raios Ultravioleta , Difração de Raios XRESUMO
The extensive production of zinc oxide (ZnO) nanomaterials (NMs) may result in high environmental zinc burdens. Honeybees need to have special concern due to their crucial role in pollination. Our previous study indicated that low concentrations of ZnO NMs, corresponding to 0.8 mg Zn/mL, have a neurotoxic potential for honeybees after a 10-day oral exposure. Present study was designed to investigate the effect of a short, dietary exposure of honeybees to ZnO NMs at concentrations 0.8-8 mg Zn/mL on consumption rate, food preference, and two enzymatic biomarkers-a stress-related glutathione S-transferase (GST) and the neurotoxicity biomarker acetylcholinesterase (AChE). Consumption rate showed a tendency toward a decrease feeding with the increasing concentrations of ZnO NMs. None of Zn NMs concentrations caused alterations in mortality rate and in the activities of brain GST and AChE. To investigate if there is an avoidance response against Zn presence in food, 24-h two-choice tests were performed with control sucrose diet versus sucrose suspensions with different concentrations of ZnO NMs added. We demonstrated that honeybees prefer ZnO NMs ZnO NMs containing suspensions, even at highest Zn concentrations tested, compared with the control diet. This indicates that they might be able to perceive the presence of ZnO NMs in sucrose solution. Because honeybees feed frequently the preference towards ZnO NMs might have a high impact on their survival when exposed to these NMs.
Assuntos
Abelhas/fisiologia , Nanoestruturas/toxicidade , Testes de Toxicidade Subcrônica , Óxido de Zinco/toxicidade , Acetilcolinesterase/metabolismo , Animais , Glutationa Transferase/metabolismoRESUMO
Nano-sized cerium dioxide (CeO2) particles are emerging as an environmental issue due to their extensive use in automobile industries as fuel additives. Limited information is available on the potential toxicity of CeO2 nanoparticles (NPs) on terrestrial invertebrates through dietary exposure. In the present study, the toxic effects of CeO2 NPs on the model soil organism Porcellio scaber were evaluated. Nanotoxicity was assessed by monitoring the lipid peroxidation (LP) level and feeding rate after 14-days exposure to food amended with nano CeO2. The exposure concentration of 1000 µg of CeO2 NPs g-1 dry weight food for 14 days significantly increased both the feeding rate and LP. Thus, this exposure dose is considered the lowest observed effect dose. At higher exposure doses of 2000 and 5000 µg of CeO2 NPs g-1 dry weight food, NPs significantly decreased the feeding rate and increased the LP level. Comparative studies showed that CeO2 NPs are more biologically potent than TiO2 NPs, ZnO NPs, CuO NPs, CoFe2O4 NPs, and Ag NPs based on feeding rate using the same model organism and experimental setup. Based on comparative metal oxide NPs toxicities, the present results contribute to the knowledge related to the ecotoxicological effects of CeO2 NPs in terrestrial invertebrates exposed through feeding.
Assuntos
Cério/toxicidade , Isópodes/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Poluentes do Solo/toxicidade , Animais , Feminino , MasculinoRESUMO
BACKGROUND: We studied the effect of carbon black (CB) agglomerated nanomaterial on biological membranes as revealed by shapes of human erythrocytes, platelets and giant phospholipid vesicles. Diluted human blood was incubated with CB nanomaterial and observed by different microscopic techniques. Giant unilamellar phospholipid vesicles (GUVs) created by electroformation were incubated with CB nanomaterial and observed by optical microscopy. Populations of erythrocytes and GUVs were analyzed: the effect of CB nanomaterial was assessed by the average number and distribution of erythrocyte shape types (discocytes, echinocytes, stomatocytes) and of vesicles in test suspensions, with respect to control suspensions. Ensembles of representative images were created and analyzed using computer aided image processing and statistical methods. In a population study, blood of 14 healthy human donors was incubated with CB nanomaterial. Blood cell parameters (concentration of different cell types, their volumes and distributions) were assessed. RESULTS: We found that CB nanomaterial formed micrometer-sized agglomerates in citrated and phosphate buffered saline, in diluted blood and in blood plasma. These agglomerates interacted with erythrocyte membranes but did not affect erythrocyte shape locally or globally. CB nanomaterial agglomerates were found to mediate attractive interaction between blood cells and to present seeds for formation of agglomerate - blood cells complexes. Distortion of disc shape of resting platelets due to incubation with CB nanomaterial was not observed. CB nanomaterial induced bursting of GUVs while the shape of the remaining vesicles was on the average more elongated than in control suspension, indicating indirect osmotic effects of CB nanomaterial. CONCLUSIONS: CB nanomaterial interacts with membranes of blood cells but does not have a direct effect on local or global membrane shape in physiological in vitro conditions. Blood cells and GUVs are convenient and ethically acceptable methods for the study of effects of various substances on biological membranes and therefrom derived effects on organisms.
Assuntos
Plaquetas/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Nanoestruturas , Fosfolipídeos/química , Fuligem/química , Adulto , Células Sanguíneas/efeitos dos fármacos , Soluções Tampão , Forma Celular/efeitos dos fármacos , Membrana Eritrocítica/efeitos dos fármacos , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Fuligem/farmacologia , Suspensões/químicaRESUMO
The exposure of organisms to microplastics could compromise their ability to cope with other environmental stressors, such as infections. In this context, we investigated the effects of a 14-day exposure of the terrestrial isopod Porcellio scaber to tire particles in soil (1.5 % w w-1 dry weight) on the organisms' response to a secondary exposure, i.e., injection of the bacterial endotoxin lipopolysaccharide. In addition, the insecticide chlorpyrifos (2 mg kg-1 dry weight) was tested as a positive control. The survival and immune response of P. scaber was assessed at the end of the 7- and 14-day primary exposure and two days after the secondary exposure, by analyzing selected haemolymph immune parameters (total haemocyte count, differential haemocyte count, and haemocyte viability). No change in survival was observed after primary exposure of P. scaber to tire particles or chlorpyrifos. However, primary exposure to chlorpyrifos triggered a strong activation of the immune response, which was not the case following exposure to the tire particles. Further injection of lipopolysaccharide into the body did not affect the survival of animals exposed to tire particles or chlorpyrifos, while a strong immunomodulatory change was observed, particularly with chlorpyrifos, and to some extent, tire particles. Based on these results, we conclude that exposure of P. scaber to tire particles or chlorpyrifos has no significant effect on the susceptibility of the organism to lipopolysaccharide in terms of their mortality, but primary exposure to an insecticide significantly modulates the immune response of the organisms to a second stressor. We discuss the "stress on stress" approach for testing low-toxic substances, such as microplastics, where an environmentally realistic exposure is followed by a secondary exposure.
Assuntos
Clorpirifos , Inseticidas , Isópodes , Animais , Inseticidas/toxicidade , Plásticos , Microplásticos , Lipopolissacarídeos/toxicidade , Clorpirifos/toxicidadeRESUMO
Mulching films, widely used in agriculture, are a large source of microplastics (MPs) to soil. However, there is little knowledge on the long-term effects of agricultural MPs on soil invertebrates. We investigated the effects of MPs from conventional non-biodegradable, fossil-based, low-density polyethylene (PE) and biodegradable fossil-based poly(butylene adipate-coterephthalate) (starch-PBAT blend) mulching films on two generations of the mealworm Tenebrio molitor. No effects of MPs (0.005 %-5 %, w/w dry food) on mealworm development and survival were observed until the end of the experiments (12 weeks for the first generation, nine weeks for the second generation), but effects on their moulting and growth were observed. These were most evident for PE MPs (5 %, w/w), where a decrease in larval growth and moulting was noted in the first generation. On the contrary, PBAT MPs (5 %, w/w) significantly induced the growth of mealworms in the second generation. In addition, there was a non-significant trend towards increased growth at all other PBAT MP exposure concentrations. Increased growth is most likely due to the biodegradation of starch PBAT MPs by mealworms. Overall, these data suggest that PE and PBAT MPs do not induce significant effects on mealworms at environmentally relevant concentrations, but rather only at very high exposure concentrations (5 %).