Affiner votre recherche
Résultats 1-10 de 19
Uptake and detoxification of diesel oil by a tropical soil Actinomycete Gordonia amicalis HS-11: Cellular responses and degradation perspectives
2020
Sowani, Harshada | Kulkarni, Mohan | Zinjarde, Smita
A tropical soil Actinomycete, Gordonia amicalis HS-11, has been previously demonstrated to degrade unsaturated and saturated hydrocarbons (squalene and n-hexadecane, respectively) in an effective manner. In present study, G. amicalis HS-11 degraded 92.85 ± 3.42% of the provided diesel oil [1% (v/v)] after 16 days of aerobic incubation. The effect of different culture conditions such as carbon source, nitrogen source, pH, temperature, and aeration on degradation was studied. During degradation, this Actinomycete synthesized surface active compounds (SACs) in an extracellular manner that brought about a reduction in surface tension from 69 ± 2.1 to 30 ± 1.1 mN m⁻¹ after 16 days. The morphology of cells grown on diesel was monitored by using a Field Emission Scanning Electron Microscope. Diesel-grown cells were longer and clumped with smooth surfaces, possibly due to the secretion of SACs. The interaction between the cells and diesel oil was studied by Confocal Laser Scanning Microscope. Some cells were adherent on small diesel droplets and others were present in the non-attached form thus confirming the emulsification ability of this organism. The fatty acid profiles of the organism grown on diesel oil for 48 h were different from those on Luria Bertani Broth. The genotoxicity and cytotoxicity of diesel oil before and after degradation were determined. Cytogenetic parameters such as mitotic index (MI); mitosis distribution and chromosomal aberration (type and frequency) were assessed. Oxidative stress was evaluated by measuring levels of catalase, superoxide dismutase and concentration of malondialdehyde. On the basis of these studies it was deduced that the degradation metabolites were relatively non-toxic.
Afficher plus [+] Moins [-]Whole-transcriptome analysis of the toxic effects of zearalenone exposure on ceRNA networks in porcine granulosa cells
2020
Zearalenone (ZEA), an estrogen-like mycotoxin, is commonly detected in animal feeds including improperly stored grains. It has been well demonstrated that ovarian granulosa cells (GCs) perform vital roles during follicular development, however, the competing endogenous RNA (ceRNA) network in GCs after ZEA exposure remains to be well described. Here, for the first time, we adopted whole-transcriptome sequence technology to explore the molecular mechanism of ZEA toxicology on porcine GCs. The results provide evidence that the cell cycle of porcine GCs is arrested in the G2/M phase after exposure to ZEA. Furthermore, bioinformation analysis found that cell cycle arrest related genes were perturbed, including CDK1, CCNB1, CDC25A, and CDC25C, which was consistent with the results of RT-qPCR, immunofluorescence, and Western Blotting. Based on the whole-transcriptome sequence data, by constructing ceRNA networks related to cell cycle arrest, we observed that ZEA exposure arrested cell cycle progression at the G2/M phase in porcine GCs, and non-coding RNAs (ncRNAs) played an important role in this process via regulating the expressions of cell cycle arrest related genes. Taken together, our data here provides strong data to support that the toxicological mechanism regarding the widely distributed toxicant ZEA acts through ceRNA networks in porcine granulosa cells.
Afficher plus [+] Moins [-]Visible-light reduced silver nanoparticles’ toxicity in Allium cepa test system
2020
Souza, Irisdoris R. | Silva, Lucas R. | Fernandes, Letícia S.P. | Salgado, Lilian D. | Silva de Assis, Helena C. | Firak, Daniele S. | Bach, Larissa | Santos-Filho, Ronaldo | Voigt, Carmen L. | Barros, Ariana C. | Peralta-Zamora, Patricio | Mattoso, Ney | Franco, Celia Regina C. | Soares Medeiros, Lia C. | Marcon, Bruna H. | Cestari, Marta M. | Sant’Anna-Santos, Bruno F. | Leme, Daniela M.
Silver nanoparticles (AgNPs) are widely used in consumer products due to their antibacterial property; however, their potential toxicity and release into the environment raises concern. Based on the limited understanding of AgNPs aggregation behavior, this study aimed to investigate the toxicity of uncoated (uc-AgNP) and coated with polyvinylpyrrolidone (PVP-AgNP), at low concentrations (0.5–100 ng/mL), under dark and visible-light exposure, using a plant test system. We exposed Allium cepa seeds to both types of AgNPs for 4–5 days to evaluate several toxicity endpoints. AgNPs did not cause acute toxicity (i.e., inhibition of seed germination and root development), but caused genotoxicity and biochemical alterations in oxidative stress parameters (lipid peroxidation) and activities of antioxidant enzymes (superoxide dismutase and catalase) in light and dark conditions. However, the light exposure decreased the rate of chromosomal aberration and micronuclei up to 5.60x in uc-AgNP and 2.01x in PVP-AgNP, and 2.69x in uc-AgNP and 3.70x in PVP-AgNP, respectively. Thus, light exposure reduced the overall genotoxicity of these AgNPs. In addition, mitotic index alterations and morphoanatomical changes in meristematic cells were observed only in the dark condition at the highest concentrations, demonstrating that light also reduces AgNPs cytotoxicity. The light-dependent aggregation of AgNPs may have reduced toxicity by reducing the uptake of these NPs by the cells. Our findings demonstrate that AgNPs can be genotoxic, cytotoxic and induce morphoanatomical and biochemical changes in A. cepa roots even at low concentrations, and that visible-light alters their aggregation state, and decreases their toxicity. We suggest that visible light can be an alternative treatment to remediate AgNP residues, minimizing their toxicity and environmental risks.
Afficher plus [+] Moins [-]Silica nanoparticles induce spermatogenesis disorders via L3MBTL2-DNA damage-p53 apoptosis and RNF8-ubH2A/ubH2B pathway in mice
2020
Liu, Jianhui | Li, Xiangyang | Zhou, Guiqing | Sang, Yujian | Zhang, Yue | Zhao, Yanzhi | Ge, Wei | Sun, Zhiwei | Zhou, Xianqing
Silica nanoparticles (SiNPs) can reduce both quality and quantity of sperm via inhibiting the progress of meiosis and mitosis and inducing apoptosis of spermatogenic cells, however, their specific mechanism and effects on the later stage of spermatogenesis are still unclear. To investigate the effects of SiNPs on the reproductive system, male mice were treated with SiNPs (0, 1.25, 5 and 20 mg/kg.bw) via intratracheal instillation once every 3 days and for a total of 15 days. Results revealed that exposure to SiNPs induced reduction in the rate of sperm activity, histological abnormalities in seminiferous epithelium as well as apoptosis of spermatogenic cells, which are associated with decreased level of Lethal (3) malignant brain tumor like 2 (L3MBTL2) and activation of DNA damage-p53-mitochondrial apoptosis pathways. Moreover, reduction in L3MBTL2 level caused by SiNPs also led to the lower expression of RNF8-ubH2A/ubH2B pathway, thus resulting in incomplete histone-to-protamine exchange. These results suggest that the inhibition of L3MBTL2 expression caused by SiNPs not only activates DNA damage-p53-mitochondrial apoptosis pathway leading to the apoptosis of spermatogenic cells, but also inhibits RNF8-ubH2A/ubH2B pathway resulting in incomplete histone-to-protamine exchange, thereby affected spermatogenesis. This indicates that L3MBTL2 plays an important role in reproductive toxicity of males caused by SiNPs.
Afficher plus [+] Moins [-]Cytogenotoxic activity of the pesticides imidacloprid and iprodione on Allium cepa root meristem
2020
Fioresi, Vinicius Sartori | de Cássia Ribeiro Vieira, Bárbara | de Campos, José Marcello Salabert | da Silva Souza, Tatiana
Effects of imidacloprid and iprodione, isolated and in mixture, were assessed by using seed germination and root growth test, flow cytometry, and chromosomal aberrations test on Allium cepa root meristem. The highest concentrations of imidacloprid, including field concentration, increased the frequency of sub-G₁ particles, decreased the frequency of nuclei in G₂/M, increased the coefficient of variation of G₁ (CVG₁) and the frequency of aberrant cells, and inhibited the mitotic index culminating in the reduction in root length. All doses of iprodione also presented cytogenotoxic action. The highest concentration of the fungicide affected the growth of A. cepa roots. In response to exposure to pesticide mixtures, the cell cycle of A. cepa was blocked in the G₁ phase. The mixtures with low doses of the pesticides significantly decreased the mitotic index, and as a consequence, the genotoxicity was reduced. In the mixtures with the highest doses of the agrochemicals, the blockage of the cell cycle was insufficient for damage repair, resulting in a significant increase of chromosomal aberrations. The results suggest caution in the use of pesticides doses that induce cytological abnormalities in non-target organisms.
Afficher plus [+] Moins [-]Efficiency of Heterogeneous Photocatalysis with Titanium Dioxide in the Alteration of Physicochemical and Toxicological Parameters of Textile Effluent
2020
Fontana, Michelli | Tonial, Ivane B. | Pokrywiecki, Ticiane Sauer | Pokrywiecki, Juan C. | Manosso, Fernando C. | Gomes, Eduardo M. V. | Düsman, Elisângela
Textile industry is responsible for producing a large amount of effluent. The objective of the present study was to treat the raw effluent of a textile manufacturer through heterogeneous photocatalysis (TiO₂/UVₛₒₗₐᵣ). Four types of effluents were evaluated: raw (RE), treated by the manufacturer (MTE), and exposed to photocatalysis in the presence (PTETi) and absence (PTE) of titanium dioxide (TiO₂). They were evaluated for physical, chemical, and toxicological parameters. In regard to dissolved oxygen (DO) contents, MTE, PTETi, and PTE effluents increased values when compared with RE effluent. Color degradation was more efficient by MTE effluent, but the chemical oxygen demand (COD) values of the treated effluents were not in accordance with Brazilian norms. Besides that, the toxicity test with Allium cepa L. shows cytotoxicity by MTE (24 and 48 h) effluent. PTETi and PTE (24 h) effluents did not show cytotoxicity, but PTETi-48 h showed a significant decrease in mitotic index. The immobility/mortality test with Artemia salina L. showed toxicity of the RE and MTE effluents in concentrations of 100% and 50%. In the case of the phototreated effluents, there was only toxicity in the concentration of 100%. Thus, so generally, photocatalytic treatments were more efficient than the treatment applied by the manufacturer; however, it is necessary to improve a new stage in the treatment.
Afficher plus [+] Moins [-]Determination of protective effect of carob (Ceratonia siliqua L.) extract against cobalt(II) nitrate-induced toxicity
2020
Macar, Oksal | Kalefetoğlu Macar, Tuğçe | Çavuşoğlu, Kültiğin | Yalçın, Emine
Cobalt (Co) is widely used in many industrial fields such as batteries and paints. Cobalt, a dangerous heavy metal, can be found in high concentrations in natural and human habitats. Although cobalt is an important micronutrient, it is toxic to living organisms when exposed to high amounts. Carob (Ceratonia siliqua L.) is a tree native to The Mediterranean region. Carob bean, which has high nutritional and economic value, is used against cardiovascular and gastrointestinal diseases. In addition, the antioxidant properties of carob are gaining importance in recent years. In this study, the protective effects of carob extract against the toxicity of cobalt on Allium cepa L. were investigated. For this purpose, 150 mg/L and 300 mg/L carob extract solutions and 5.5 mg/kg cobalt solutions were applied to A. cepa L. bulbs. Root emergence, weight gain, root elongation, and mitotic index (MI) decreased, while the frequency of chromosomal abnormalities (CAs) and micronucleus (MN) increased as a result of Co application. Furthermore, Co treatment triggered a noticeable rise in the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes as well as the malondialdehyde (MDA) amount and the abnormalities in the meristematic cells. On the other hand, applications of carob extracts mitigated cobalt-induced damages in a dose-dependent manner in all parameters. Therefore, the current study showed that the strong preventive potential of carob extract against phytotoxicity and genotoxicity is caused by Co in a model plant. The protective effects of carob extract on Co-induced toxicity were demonstrated for the first time in terms of reducing genotoxicity and oxidative stress response.
Afficher plus [+] Moins [-]Cytotoxic, Genotoxic, Mutagenic, and Phytotoxic Effects of the Extracts from Eragrostis plana Nees, 1841 (Poaceae), Grown in a Coal-Contaminated Region
2020
Artico, Leonardo Luís | Kömmling, Gizele | Clarindo, Wellington Ronildo | Menezes, Ana Paula Simões
Coal and its byproducts and mineral waste constitute complex mixtures, which contain a variety of chemical compounds that impact the ecosystems. For this reason, procedures are required to monitor coal-degraded areas, including the use of biomonitoring organisms. In this light, the aim of the present study was to evaluate the cytotoxicity, genotoxicity, mutagenicity, and phytotoxicity of the aerial part and root extracts from Eragrostis plana Nees collected in the surroundings of the Thermoelectric Power Plant President Médici-UTPM (Candiota, Brazil), through Allium cepa bioassay. Cytotoxicity, genotoxicity, and mutagenicity in the A. cepa meristematic cells were verified through the mitotic index (MI), chromosomal alterations, and micronucleus formation, respectively. In addition, the germination rate, vigor index, and morphological abnormalities were verified in A. cepa seedlings. Treatment with root extracts from E. plana (ACR) specimens collected in a coal-contaminated region resulted in the lowest MI values (8.9%, 12.7%, and 16.0%), representing the most cytotoxic effect when compared with the negative control—NC (dH₂O) (MI = 35.8%). ACR extract also was the most genotoxic and mutagenic sample compared with NC and other treatments. Phytotoxicity analyses corroborated the toxic action of ACR, presenting abnormal seedlings and change in vigor index. The high concentration of dissolved total chlorides and electrical conductivity presented in the root extracts of E. plana, which were grown in the carboniferous region, indicates an increase in the absorption of metallic ions and organic compound and supports the hypothesis that this species has bioaccumulator potential, being a new biomonitor model of coal-contaminated region.
Afficher plus [+] Moins [-]In vivo protective effects of Ginkgo biloba L. leaf extract against hydrogen peroxide toxicity: cytogenetic and biochemical evaluation
2020
Yalçın, Emine | Çavuşoğlu, Kültiğin | Acar, Ali | Yapar, Kürşad
In this study, the protective effects of Ginkgo biloba leaf extract (GbE) against toxicity induced by hydrogen peroxide (H₂O₂) in Swiss albino mice were investigated. Abnormal metaphase number (AMn), mitotic index (MI), micronucleus (MN), and chromosomal abnormalities (CAs) were analyzed for cytogenetic effects. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), creatinine, glutathione (GSH), and malondialdehyde (MDA) levels in liver and kidney organs were investigated as indicators of biochemical toxicity. Six experimental groups were formed as a control and treatment group, each containing six animals. The mice in the control group were given tap water, while the mice in the administration group received two different doses of GbE and H₂O₂ for 45 consecutive days. It was observed that H₂O₂ administration caused a significant decrease in MI compared to the control group and caused a significant decrease in the frequency of AMn, MN, and CAs. Chromatid break was the most common type of CAs induced by H₂O₂, and the other CAs types observed in this study were chromosome break, fragment, dicentric, gap, and ring. It has been determined that GbE treatment decreases the clastogenic effects of H₂O₂ and reduces the MN and CAs frequency and causes a re-increase in mitotic cell numbers. It was determined that H₂O₂ administration caused changes in biochemical parameters and resulted in significant increases in serum AST, ALP, ALT, BUN, and creatinine levels. However, the level of MDA, which is an indicator of oxidative damage, increased, and GSH level decreased in liver and kidney tissues. Oxidative damage caused by H₂O₂ in liver and kidney tissues was improved, and all biochemical parameters tested were found to be ameliorated after GbE treatment. This improvement was dependent on the dose of GbE, and improvement in 150 mg/kg bw GbE was found to be more prominent. As a result, the GbE can be used as an antioxidant nutritional supplement to protect against the toxic effects of environmental agents such as H₂O₂.
Afficher plus [+] Moins [-]Resveratrol ameliorates the physiological, biochemical, cytogenetic, and anatomical toxicities induced by copper(II) chloride exposure in Allium cepa L
2020
Excessive copper (Cu) exposure ultimately results in toxicosis in all organisms. The protective potential of resveratrol compound against the CuCl₂ toxicity was evaluated in Allium cepa L. root tip cells. For this aim, A. cepa bulbs were divided into six groups and the groups were treated with tap water, 400 mg/L resveratrol, 800 mg/L resveratrol, 20 μM CuCl₂, 400 mg/L resveratrol + 20 μM CuCl₂, and 800 mg/L resveratrol + 20 μM CuCl₂ solutions, respectively for 72 h. The first group irrigated with tap water was accepted as control. All groups were screened for the germination percentage, root elongation, total bulb weight gain, micronucleus (MN) frequency, mitotic index (MI), chromosomal aberrations, and anatomical changes. Furthermore, superoxide dismutase (SOD) and catalase (CAT) activities as well as malondialdehyde (MDA) level as an indicator of lipid peroxidation were investigated. It was found that CuCl₂ exposure alone triggered a definite negative effects on all parameters examined. On the other hand, the groups treated with resveratrol did not have statistically different values compared to the control group. Resveratrol doses induced a remarkable recovery in growth parameters including germination percentage, root elongation, and total bulb weight gain when applied with CuCl₂. In these groups, MN frequency, chromosomal aberrations, and anatomical abnormalities were alleviated, whereas the MI levels increased significantly. Moreover, lipid peroxidation level and antioxidant enzyme activities showed a marked amelioration when resveratrol and CuCl₂ were applied together. Copper compounds have become common pollutants due to their direct uses as pesticides in agricultural areas as well as their spreading to natural areas from industrial fields. The study clearly demonstrated the therapeutic potential of resveratrol against the harmful effects of CuCl₂ exposure in Allium roots. So, resveratrol could be considered as a plant-derived restorative agent for the reduction of the risks from the other copper compounds.
Afficher plus [+] Moins [-]