Assessment on interactive prospectives of nanoplastics with plasma proteins and the toxicological impacts of virgin, coronated and environmentally released-nanoplastics

Recently, the concerns about micro- and nano-plastics (NPs) toxicity have been increasing constantly, however the investigations are quiet meager. The present study provides evidences on the toxicological prospectives of virgin-, coronated- and isolated-NPs on human blood cells and Allium cepa root tip, respectively. Several plasma proteins displayed strong affinity towards NPs and produced multi-layered corona of 13 nm to 600 nm size. The coronated-NPs often attracted each other via non-specific protein-protein attraction which subsequently induced protein-induced coalescence in NPs. In the protein point of view, the interaction caused conformational changes and denaturation of protein thereby turned it as bio-incompatible. The coronated-NPs with increased protein confirmation changes caused higher genotoxic and cytotoxic effect in human blood cells than the virgin-NPs. On the other hand, virgin-NPs and the NPs isolated from facial scrubs hindered the root growth and caused chromosome aberration (ring formation, C-mitotic and chromosomal breaks, etc.) in root of Allium cepa. At the outset, the present study highlights the urgent need of scrutinization and regulation of NPs use in medical applications and pre-requisition of additional studies for assessing the bio-accumulation and bio-magnification of NPs.

Nucleolar alterations are reliable parameters to determine the cytogenotoxicity of environmental pollutants

Pollution generated by deposition of industrial activity waste in the environment without due care can lead to serious environmental consequences. Bioassays in higher plants are means of understanding the cytogenotoxic effects of these substances. In the present work, Allium cepa L. was used as a model species to assess nucleolar changes induced by environmental pollutants. The substances used were Methyl Methane Sulfonate (MMS), cadmium (Cd), Spent Potliner (SPL) and the herbicide Atrazine. Water was used as a negative control. The silver-stained nucleolar organizer region (AgNOR) assay was used making it possible to evaluate how nucleolar parameters (number of nucleoli per nucleus and nucleoli area) behave when facing stress caused by such pollutants. The results obtained showed a variation in the observed parameters: an increase in the number of nucleoli in the treated cells and tendency to a reduction in nucleolar area, indicating that the tested pollutants may have impaired nucleolar activity. In addition, it was possible to establish a relationship between the behavior of the nucleolus with other changes as plantlet growth, cell proliferation, and DNA damage.

Phytotoxicity, cytotoxicity and genotoxicity evaluation of organic and inorganic pollutants rich tannery wastewater from a Common Effluent Treatment Plant (CETP) in Unnao district, India using Vigna radiata and Allium cepa

The leather industry is a major source of environmental pollution in India. The wastewater generated by leather industries contains very high pollution parameters due to the presence of a complex mixture of organic and inorganic pollutants even after the treatment at a Common Effluent Treatment Plant (CETP) and disturbs the ecological flora and fauna. The nature, characteristics and toxicity of CETP treated wastewater is yet to be fully elucidated. Thus, this study aims to characterize and evaluate the toxicity of CETP treated tannery wastewater collected from the Unnao district of Uttar Pradesh, India. In addition to measuring the physico-chemical parameters, the residual organic pollutants was identified by GC-MS analysis and phytotoxicity, cytotoxicity and genotoxicity of the treated wastewater was evaluated using Vigna radiata L. and Allium cepa L. Results showed that the treated wastewater contained very high pollution parameters (TDS 3850 mg/L, BOD 680 mg/L, COD-1300 mg/L). GC-MS analysis revealed the presence of various types of residual organic pollutants including benzoic acid, 3-[4^,-(T-butyl) Phenyl] furan-2-5-dione, benzeneacetamide, resorcinol, dibutyl phthalate, and benzene-1,2,4-triol. Further, toxicological studies showed the phytotoxic nature of the wastewater as it inhibited seed germination in V. radiata L. and root growth of A. cepa. Genotoxicity was evidenced in the root tip cell of A. cepa where chromosomal aberrations (stickiness, chromosome loss, C-mitosis, and vagrant chromosome) and nuclear abnormalities like micronucleated and binucleated cells were observed. Thus, results suggested that it is not safe to discharge these wastewater into the environment.

Influence of Acacia dealbata Link bark extracts on the growth of Allium cepa L. plants under high salinity conditions

BACKGROUND

Acacia dealbata Link is an invasive plant worldwide. Finding potential uses for its waste that contribute to controling its spread and result in benefits for agriculture has recently become a new topic of research. This study aimed to evaluate the potential biostimulant effect of bark extract derived from the management of A. dealbata (0, 450 or 900 ppm) on onion plants growing under stressful conditions, such as in soils treated with saline solutions (0, 60 or 120 mmol L^-1 NaCl) and with reduced irrigation (100%, 50% or 25%).

RESULTS

A. dealbata Link bark extract significantly increased height as well as leaf, root and total biomass of plants in soils irrigated with NaCl solution (120 mmol L^-1 ). These plants also had a higher content of Cl in roots, but a lower content of P in leaves and of K in bulbs. The 450 ppm bark treatment additionally increased the protein content in leaves and decreased the Na and Mg content in bulbs and bulbs and roots, respectively. The bark extract also increased the sugar content in plants under saline conditions. However, the effect of bark extract was negligible on plants that grew under drought stress.

CONCLUSION

Results revealed that the bark extract might attenuate stress effects in plants growing at high salinity levels, probably by increasing their sugar and protein content and via the accumulation of ions in the roots. Although additional experiments are required, we suggest that the bark extract of A. dealbata has potential applications in agriculture concerned with biostimulant formulations. © 2019 Society of Chemical Industry.

Determination by chromatography and cytotoxotoxic and oxidative effects of pyriproxyfen and pyridalyl

Pyriproxyfen (PPF) is a larvicide, used to combat the proliferation of Aedes aegypti larvae. The objective of this study was to analyze the compounds of pyriproxyfen and pyridalyl (PYL) in a commercial larvicide to analyze the cytotoxic and oxidative effects of PPF and PYL. The toxic potential of PPF and PYL were assessed based on lethal concentration (LC₅₀) in Artemia salina, cytotoxicity based on the mitotic index and the chromosomal alterations in Allium cepa and the oxidative damage in Saccharomyces cerevisiae. The PPF and PYL compounds were identified by HPLC-PDA based on their retention times and spectral data. The wavelengths λ_max (258 nm) and (271 nm) of the UV spectrum of PYL and PPF and the retention times (R_T) (3.38 min) and (4.03 min), respectively. The toxicological potentials of PPF and PYL were significant at concentrations (1, 10, 100 and 1000 ppm), with an LC₅₀ of 48 h (0.5 ppm). PPF and PYL pointed out a cytotoxic effect in A. cepa at all concentrations (0.0001, 0.001, 0.01, 0.1, 1.0, 100 and 1000 ppm), genotoxic effect at concentrations only (0.0001; 0.1; 1; 100 and 1000 ppm), and mutagenic for concentrations (0.1, 100 and 1000 ppm). In relation S. cerevisiae, PPF e PYL prompted oxidative damage at concentrations (100 and 1000 ppm) in all strains (SODWT, Sod1, Sod2, Sod1Sod2, Cat1 and Sod1Cat1). Therefore, the PPF and PYL identificated in commercial larvicide by HPLC-PDA produced cytotoxic and oxidative effects that could cause health and ecosystem risks.

The effect of silver nanoparticles on the mutagenic and the genotoxic properties of the urban wastewater liquid sludges

Nanoparticles are very effective compounds to transform and detoxicate common environmental contaminants. For this reason, crude urban liquid wastewater sludges were treated by silver nanoparticles (Ag-NPs, 100 nm) for 24 h. Both Ag-NPs' treated and untreated sludges were examined for the evaluation if there are possible mutagenic/anti-mutagenic, cytotoxic, and genotoxic/anti-genotoxic effects by Ames and Allium cepa tests. The results were then subjected to statistical analyses by using SPSS software and p < 0.05 was accepted as a significant value. The data obtained from the Ames test showed that while untreated crude liquid sludge had a significant mutagenic effect, Ag-NP-treated one decreased its mutagenicity. Similar effects were also observed in the chromosome aberration-Allium cepa tests. Significant chromosome aberrations observed were C-metaphase, sticky metaphase, sticky anaphase, anaphase bridge, vagrant chromosome, and multipolar anaphases. Both tests demonstrated that silver nanoparticle treatment decreased the major mutagenicity and genotoxicity detected in the liquid wastewater sludges.

Slow delivery of biocide from nanostructured, microscaled, particles reduces its phytoxicity: A model investigation

Nano-engineered delivery systems have emerged as possible solutions for more efficient pest management in agriculture. Likewise for nanostructured drug delivery systems (DDS) in medicine, the use of biocide delivery systems (BDS) brought concerns on their toxicology on non-targeted organisms. Plants, for instance, are the foundation of the ecosystem, acting as primary actor in the food chain and is associated with the whole biodiversity, being strictly related to human health. This is a very important consideration to fully understand the benefits of using delivery systems for crop protection and production. Herein, a biocide delivery system was prepared by loading nanostructured, microscaled, biogenic silica particles with thymol, a known phytotoxicant. The resulting system contains 120 mg of thymol per gram of silica and displays slow release features. The Allium cepa bioassay was chosen to demonstrate how the toxicity and cellular damages induced by thymol can be significantly reduced through a slow, controlled, release strategy. The lower mobility of the reference particles associated with slow-delivery features reduced the toxicity and cellular damages caused by thymol in the plant genetic model.

Influence of Land Use and Cover on Toxicogenetic Potential of Surface Water from Central-West Brazilian Rivers

The objective of this study was to evaluate toxicogenetic potential of surface water samples from rivers of center-west Brazil and analyze the influence of land use and cover and physicochemical parameters in genetic damage. Samples were collected during winter (June) and summer (November) at sampling sites from Dourados and Brilhante Rivers (Mato Grosso do Sul/Brazil). The toxicogenetic variables, including chromosomal alterations, micronuclei, and mitotic index, were analyzed in meristematic cells of Allium cepa; and micronuclei, nuclear abnormalities, and DNA strand breaks (arbitrary units, AU_T) were analyzed in erythrocytes of Astyanax lacustris. The rivers presented physicochemical values outside the Brazilian laws, which can be a characteristic of human pollution (domestic sewage and local agriculture). The results of A. cepa test suggest that the water samples from Dourados and Brilhante rivers exerted significant (p < 0.05) cytotoxic and genotoxic effects, in both periods of collection, especially alterations in mitotic index. In blood cells of A. lacustris, genotoxic effect of the water samples from the rivers also was observed as significant nuclear abnormalities, DNA breaks (UA_T), in both sampling periods, compared with the negative control. Spearman correlation analyses revealed that data of land use and cover and physicochemical parameters were statistically correlated with DNA damages in bioassays. This study demonstrates toxicogenetic potential of water samples from Dourados and Brilhante rivers; furthermore, the type of land use and land cover and physicochemical parameters were revealed to have influence on toxicogenetic damage.

Toxicity of silver nanoparticles released by Hancornia speciosa (Mangabeira) biomembrane

Recent research has shown that latex from different species is able to produce tissue replacement and regeneration. Particularly, biomembranes obtained from Hancornia speciosa latex (HSB) have shown high angiogenic and osteogenic activity. Considering new materials for wound healing, it would be interesting to develop a product combining antibacterial and antifungal activities. Silver nanoparticles (AgNP) have been commonly used for this purpose in medicinal products and devices for decades. In order to combine angiogenic, antibacterial and antifungal properties on the same platform, we developed an HSB containing 3 concentrations of AgNP. It was observed that the HSB successfully accommodated the AgNP in the matrix and released them in a controlled way. The release dynamics of AgNP by HSB was described by UV-vis absorption spectroscopy. The released nanoparticles were evaluated by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) measurements. In addition, the cytotoxic and genotoxic effects were evaluated using the Allium cepa assay. The results showed no cytotoxic effect of HSB-AgNP in all studied concentrations. The genotoxic effect was observed in HSB-AgNP at the two highest concentrations, however not at the lowest concentration. Thus, the addition of AgNP at the lowest concentration can improve the pharmacological activity of HSB without causing a toxic effect on vegetal cells. Therefore, the H. speciosa latex biomembrane presented in this paper combines angiogenic, anti-inflammatory and antibacterial properties and can be considered potentially new biomaterial for wound-healing.

Influences of zinc oxide nanoparticles on Allium cepa root cells and the primary cause of phytotoxicity

Zinc oxide nanoparticles (ZnO-NPs) are widely used in consumer products, which have raised concerns about their impact on the human health and environment. In this study, Allium cepa were treated with 5 and 50 μg/mL ZnO-NPs solutions for 12, 24, and 36 h, respectively. The cytotoxic and genotoxic effects of ZnO-NPs in root meristems of Allium cepa cells were characterized by cell membrane integrity, metabolic activity, reactive oxygen species (ROS) accumulation, DNA damage, chromosome aberration, and cell cycle progression. Substantially elevated Zn levels were observed in the cytoplasmic and nuclear fractions, and the accumulation of zinc in the nuclear fraction (up to 9764 μg/g) was one magnitude greater than that in the cytoplasm (up to 541 μg/g). The complexation of Zn²⁺ with diethylene triamine pentacetic acid (DTPA) was performed to explicate the respective contribution of insoluble particles or Zn²⁺ to ZnO-NPs toxicity. We found that the inhibition of root growth accounted for 24.2% or 36.1% when the plants were exposed to Zn²⁺ that released from 5 or 50 μg/mL of ZnO-NPs for 36 h, respectively, whereas the exposure to 5 or 50 μg/mL of insoluble particles resulted in 75.8% or 63.9% of inhibition, respectively. These findings demonstrated that adverse effects exerted not just by Zn²⁺ released from ZnO-NPs, but also directly from the nanoparticles. These findings contribute to a better understanding of ZnO-NPs cytotoxicity and genotoxicity in plant cells and provide valuable information for further research on the phytotoxic mechanisms of ZnO-NPs.

Environmental risk appraisement of disinfection by-products (DBPs) in plant model system: Allium cepa

The organic toxicants formed in chlorinated water cause potential harm to human beings, and it is extensively concentrated all over the world. Various disinfection by-products (DBPs) occur in chlorinated water are genotoxic and carcinogenic. The toxicity is major concern for chlorinated DBPs which has been present more in potable water. The purpose of the work was to evaluate genotoxic properties of DBPs in Allium cepa as a plant model system. The chromosomal aberration and DNA laddering assays were performed to examine the genotoxic effect of trichloroacetic acid (TCAA), trichloromethane (TCM), and tribromomethane (TBM) in a plant system with distinct concentrations, using ethyl methanesulfonate (EMS) as positive control and tap water as negative control. In Allium cepa root growth inhibition test, the inhibition was concentration dependent, and EC₅₀ values for trichloroacetic acid (TCAA), trichloromethane (TCM), and tribromomethane (TBM) were 100 mg/L, 160 mg/L, and 120 mg/L respectively. In the chromosome aberration assay, root tip cells were investigated after 120 h exposure. The bridge formation, sticky chromosomes, vagrant chromosomes, fragmented chromosome, c-anaphase, and multipolarity chromosomal aberrations were seen in anaphase-telophase cells. It was noticed that with enhanced concentrations of DBPs, the total chromosomal aberrations were more frequent. The DNA damage was analyzed in roots of Allium cepa exposed with DBPs (TCAA, TCM, TBM) by DNA laddering. The biochemical assays such as lipid peroxidation, H₂O₂ content, ascorbate peroxidase, guaiacol peroxidase, and catalase were concentration dependent. The DNA interaction studies were performed to examine binding mode of TCAA, TCM, and TBM with DNAs. The DNA interaction was evaluated by spectrophotometric and spectrofluorometric studies which revealed that TCAA, TCM, and TBM might interact with Calf thymus DNA (CT- DNA) by non-traditional intercalation manner.

Cytotoxicity and genotoxicity of cerium oxide micro and nanoparticles by Allium and Comet tests

Cerium oxide (CeO₂) is extensively used in a range of applications like in television tubes, glass/ceramic polishing agent, fuel cells, solar cells, gas sensor andultraviolet absorbents. In current study, Allium ana-telophase and comet assays were employed to evaluate the cytotoxic and genotoxic effects of CeO₂ microparticles (CMPs, <5 µm, bulk) and CeO₂ nanoparticles (CNPs, < 25 nm) on the root meristem cells of Allium cepa by using mitotic phases, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. A cepa roots were treated with the CMPs and CNPs at four different concentrations (12.5, 25, 50, and 100 ppm) for 4 h. Methyl methane sulphonate (MMS,10 ppm) and distilled water were used as positive and negative control groups, respectively. All the applied doses statistically decreased MIs. MI values of CMPs were found higher than CNPs. CMPs and CNPs significantly increased CAs such as chromosome laggards, disturbed anaphase-telophase, stickiness and bridges and also DNA damage. Characterization of CMPs and CNPs showed the particle size as 4.24 ± 0.7 µm and 20.28 ± 2.33 nm, respectively. The average diameter of CMPs and CNPs in solution were in the range of 372.75 ± 70.23 nm and 167.74 ± 38.7 nm, respectively. These results demonstrated that CMPs and CNPs had cytotoxic and genotoxic effects in A. cepa root meristematic cells.

Rapid and green synthesis of cadmium telluride quantum dots with low toxicity based on a plant-mediated approach after microwave and ultrasonic assisted extraction: Synthesis, characterization, biological potentials and comparison study

In this work, a quick, facile and efficient approach was presented for green synthesis of cadmium telluride quantum dots (CdTe QDs) based on an aqueous extract of the Ficus johannis plant. Two extraction methods involving microwave assisted extraction (MWAE; 90 and 270 w; 15 min) and ultrasonic assisted extraction (USAE; 15 min; 45 °C) were performed as eco-friendly, effective, green and fast techniques for the extract preparation of the fruit's plant. The as-prepared plant extracts were used as natural stabilizing precursors in the synthesis of CdTe QDs. The synthesized QDs were characterized using various techniques. The average particle size of the QDs from the X-ray diffraction patterns was calculated to be 1.2 nm. UV-Vis absorption and fluorescence spectroscopic studies show a wide absorption band from 400 to 425 nm and a maximum emission peak around 470 nm, which confirmed the successful synthesis of CdTe QDs via the applied synthetic method. After synthesis and characterization of the samples, the antimicrobial properties, genotoxicity, toxicity and antifungal activities of the as-prepared CdTe QDs were investigated. In addition, antioxidant properties of the samples (QDs and extracts), were evaluated by different antioxidant assays. The results indicate the significant antimicrobial activity of the extract and CdTe QDs samples, with negligible toxicity and genotoxicity impacts.

From collection to discharge: physical, chemical, and biological analyses for fish farm water quality monitoring

The use of chemical substances for the management of fish farming activities may compromise the quality of the tank water itself and of water bodies that receive the effluents. As studies that assess the environmental effect caused by pisciculture are scarce, the present study aimed at evaluating the water quality in two fish farms in the region of Grande Dourados, Brazil, from the site of water collection to the site of water disposal. The tools used for this purpose were the analysis of land use and cover and the determination of physical, chemical, and biological parameters of water samples. Maps of land use and cover were created, and water samples were collected at four sampling sites in two fish farms. The Allium cepa test, assays with Astyanax lacustris, and the Salmonella/microsome assay were performed. In addition, physical and chemical parameters were measured and metal and emerging contaminants in the water samples were investigated. The A. lacustris demonstrated the genotoxicity and the Salmonella/microsome assay suggested the mutagenic potential of water samples from the fish farms and indicated higher genotoxicity in the disposal tanks than in the collection tanks of the Brilhante fish farm. However, all the samples at the Dourados fish farm were genotoxic, and mutagenicity was shown to start at the water collection site. With regard to the A. cepa test, there was no statistical difference between the collection sites in both fish farms. Moreover, the observed genetic damage may be associated with the presence of metals and emerging contaminants in the water samples, which suggests that these chemicals have potential genotoxic and mutagenic effects that are related to the type of land use and cover in the area of the region studied. Considering that contaminated waters can potentially disturb the structure and functioning of natural ecosystems, the present study demonstrated the importance of treating fish farm effluent to minimize the negative effect of this activity on water bodies.

Far-reaching cytogenotoxic effects of mine waste from the Fundão dam disaster in Brazil

On November 2015, one of Brazil's most important watersheds was impacted by the mine waste from Fundão dam collapse in Mariana. The mine waste traveled over 600 km along the Doce River before reaching the sea, causing severe devastation along its way. Here we assessed trace element concentrations and cytogenotoxic effects of the released mine waste. Water samples were collected along the Doce River ten days after the disaster in two impacted sites and one non-impacted site. Sampling points were located hundreds of kilometers downstream of the collapsed dam. Water samples were used for trace element quantification and to run an experiment using Allium cepa to test cytogenotoxicity. We found extremely high concentrations of particulate Fe, Al, and Mn in the impacted sites. We observed cytogenotoxic effects such as alterations in mitotic and phase indexes, and enhanced frequency of chromosomal aberrations. Our results indicate interferences in the cell cycle in impacted sites located hundreds of kilometers downstream of the disaster. The environmental impacts of the dam collapse may not only be far-reaching but also very likely long-lasting, because the mine waste may persist in the Doce River sediment for decades.

Benzoxazoles as novel herbicidal agents

BACKGROUND

Despite the need to develop new herbicides with different modes of action, due to weed resistance, many important classes of compounds have been studied poorly for this purpose. Benzoxazoles are considered privileged structures because of their biological activities, but their phytotoxic activities have not received a lot of attention until now.

RESULTS

Double vinylic substitution reactions were carried out to furnish four 2-nitromethylbenzoxazoles and one oxazolidine. Benzoxazol-2-ylmethanamine was obtained by reduction of compound 3a. These compounds were evaluated for their phytotoxicity in Allium cepa (onion), Solanum lycopersicum (tomato), Cucumis sativus (cucumber) and Sorghum bicolor (sorghum). Comparison with oxazolidine analogue allowed us to understand that the benzoxazolic structure is very important for the herbicidal activity.

CONCLUSION

All the synthesized compounds exhibited biological activity on seed germination. The four 2-nitromethylbenzoxazoles showed phytotoxic activity and the 5-chloro-2-(nitromethyl)benzo[d]oxazole (3b) exhibited higher inhibition than the commercial herbicide against all four plant species tested. © 2018 Society of Chemical Industry.

Genetic toxicity of water contaminated by microcystins collected during a cyanobacteria bloom

Microcystin-LR (MCLR) is a toxin mainly produced by Microcystis aeruginosa, cyanobacteria most commonly found in eutrophic environments. Cyanobacteria blooms have affected Salto Grande reservoir (Americana, State of São Paulo/Brazil) for several decades, often observed during periods of drought. In this study, the genotoxic effects of MCLR (95% purity) and water samples contaminated by this toxin were evaluated during cyanobacteria bloom using assays with the test organism Allium cepa. The results showed genotoxic action for pure microcystin and cytotoxic, genotoxic and mutagenic action for water samples collected during flowering. Chromosomal aberration assays have shown that MCLR induces chromosomal breaks that persist in the daughter cells as MN. Therefore, it is possible to infer a clastogenic action for this toxin. The MCLR present in the environmental samples was shown to be more cytogenotoxic for the cells than the different concentrations tested in this study with the pure substance. This amplified toxic action can be related to a synergistic effect between the MCLR and other compounds present in the environmental samples. The genotoxicity studies with MCLR show inconsistent and inconclusive results, so this toxin needs to be better investigated in order to obtain further information about the action mode of it is on the biological system.

Determination of the Environmental Pollution Potential of Some Herbicides by the Assessment of Cytotoxic and Genotoxic Effects on Allium cepa

The present study aims to evaluate the potential for the pollution of the environment by two herbicides (quizalofop-p-ethyl and cycloxydim), using the Allium test. The species in question is Allium cepa (onion, 2n = 16), one of the most common plant indicators of environmental pollution. The working method consisted of obtaining the meristematic roots of Allium cepa and their treatment with herbicides at three different concentrations (0.5%, 1%, and 1.5%) for each herbicide for 24 h, for comparison with an untreated control. The results obtained from the cytological study indicated a strong cytotoxic and genotoxic effect for both herbicides, but especially for quizalofop-p-ethyl, where the mitotic index decreased from 30.2% (control) to 9.6% for the variant treated with 1.5% herbicide. In this case, a strong mitodepressive effect was shown by a highly significant percentage (35.4%) of chromosomal aberrations and nuclear alterations: stickiness, fragments, C-mitosis, lobulated nucleus, micronuclei, and nuclear erosion. The mitodepressive effect as well as the percentage of chromosomal aberrations increased with a higher herbicide concentration. The obtained results suggest the strong potential for pollution of the two herbicides, particularly at concentrations higher than 0.5%; therefore, we recommend caution in their use to avoid undesirable effects on the environment.

Cytogenetic and genotoxic effects of 2-chlorophenol on Allium cepa L. root meristem cells

2-Chlorophenol (2-CP), a class of chlorinated organic pollutants like other chlorophenols, is used as intermediate in the synthesis of the higher chlorinated congeners, certain dyes, preservatives, herbicides, fungicides, and plastics. In this study, cytotoxic and genotoxic effects of 2-CP were investigated on the root meristem cells of Allium cepa for its effects on root growth, mitotic index (MI), mitotic phases, chromosomal abnormalities (CAs), and DNA damage by using Allium anaphase-telophase and Comet assays. EC₅₀ of 2-CP value was determined as approximately 25 mg/L by Allium root growth inhibition test. Three concentrations of 2-CP (12.5, 25, and 50 mg/L), distilled water (negative control), and methyl methane sulfonate (MMS, 10 mg/L, positive control) were applied to onion stem cells under different exposure periods (24, 48, 72, and 96 h). All the applied doses of 2-CP slightly decreased MIs. 2-CP induced total CAs such as disturbed anaphase-telophase, chromosome laggards, stickiness, and bridges and also DNA damage at significant levels. These results demonstrate that 2-CP has genotoxic effects in A. cepa root meristematic cells.

Protective role of jaboticaba Plinia peruviana peel extract in copper-induced cytotoxicity in Allium cepa

Jaboticaba Plinia peruviana (Poir.) Govaerts is a Brazilian berry that presents high levels of polyphenols, which may play a key role in preventing cytotoxic and genotoxic effects of harmful agents. Although copper is an essential micronutrient that plays an important role in organisms, high copper concentrations may trigger toxicity to animals and plants. Here, we investigated whether Plinia peruviana hydroalcoholic extract prevents copper-induced cytotoxicity in Allium cepa root cells. Five different anthocyanins and phenolic compounds were identified in Plinia peruviana extract. Importantly, the exposure to 1.53 mg/L copper for 24 h impaired mitotic index, as well as increased mitosis disturbances and triggered DNA damage. Pre-incubation with Plinia peruviana extract (0.25 g/L and 0.75 g/L) for 3 h prevented copper-induced changes in the mitotic index and reduced the number of abnormal cells. In conclusion, we suggest that Plinia peruviana peel extract has protective effects against cellular and genetic disturbances induced by copper.

Assessment of anticytotoxic effect of lichen Cladonia foliacae extract on Allium cepa root tips

The aim of this study is to investigate the protective effect of lichen Cladonia foliacae (Huds.) (CF) on hydrogen peroxide (H₂O₂)-induced toxicity through cell death, chromosome aberrations, mitotic index, oxidative stress parameters, and DNA damage in a Allium cepa root meristematic cells. Any chemical was not given for control group. Two doses of H₂O₂ (3 and 7%) were given to the roots for 1 h and the root tips were treated with CF water extract (50 and 100 μL) with increasing times for treatment groups. The roots were taken from control and treatment groups, and mitotic index, cell death, and chromosome aberrations were performed by light microscope. Changing antioxidant capacity of roots was revealed by FRAP and TEAC assay. Also, DNA damage was measured by comet assay and RAPD-PCR technique. Chromosome aberration values were obtained with increasing concentrations with longer treatment times, such as chromosome bridge, vagrant, and polyploidy in both groups. Increasing exposure doses of H₂O₂ caused decreasing mitotic index values at 72 h. TEAC and FRAP assay demonstrated that roots' capacity of antioxidant was altered by increasing concentrations of H₂O₂. The tail DNA% and tail length significantly increased in all exposure times when compared to control group. Three and seven percent of H₂O₂ caused the genotoxic effect on genetic material at 72 h according to RAPD-PCR technique. Increasing the doses of H₂O₂ resulted in increased toxicity to all studied parameters of A. cepa, but CF extract altered all changing parameters of A. cepa root cell. The H₂O₂ tested in this study have cytotoxic and mutagenic potential, but extract of CF was protective against H₂O₂ caused toxicological changes. But, it did not protect completely in the A. cepa root meristematic cells.

Evaluation of textile laundry effluents and their cytotoxic effects on Allium cepa

Industrial laundries have water as one of their main inputs and they release effluents in large amounts, with a high polluting load, which are usually discarded into the environment, or they are insufficiently treated for release into the neighboring water bodies. The aim of this study was to evaluate the efficiencies of the biological treatments in an industrial textile laundry and their environmental impact on the surface waters of the stream where the dump is usually made, by using cytotoxicity tests on the meristematic root cells of Allium cepa L. The results have shown, for the most part, that the treated effluents over a period of 24 h showed reductions in their mitotic index. The treatments on the raw effluents showed cytotoxic effects when compared to control, with cell division recoveries after 24 h in the waters. Cytotoxic effects were additionally observed in the stream waters, at a point before the dump, indicating that they received a pollutant load, before the effluent disposal site of the evaluated industrial laundry. Notably, the treatments that were being applied by the industrial laundry were effective throughout the processing, reducing the concentrations of the toxic substances. When considering the data presented, it is now understood that there is a constant need for the evaluation of industrial effluents, as well as for the waters of the streams and the rivers that receive these disposals, in order to preserve and maintain the quality of the waters, the organisms, and consequently, the ecosystems.

Mutagenic effects of spent potliner and derivatives on Allium cepa L. and Lactuca sativa L.: A molecular approach

Spent potliner (SPL) is a solid residue generated by the aluminum industry. Its composition is variable and complex, containing fluoride and cyanide salts as well as aluminum, which contributes to its toxicity. SPL is sometimes released directly into the soil, where it is prone to leaching and has the potential to cause alterations and damage to DNA. Considering that polymorphism analysis of simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) DNA markers is an interesting tool to determine the mutagenicity of an environmental pollutant, the present study adopted this approach to verify the mutagenic potential of SPL and its main toxic components (aluminum, fluoride, and cyanide) on root tip cells of Lactuca sativa and Allium cepa. Alterations in ISSR and SSR regions were identified by DNA fingerprinting (gain and loss of bands and changes in band intensity). The estimated dissimilarities indicated differences between treatments and the negative control. Furthermore, the relationship between the amplification profile of the markers and alterations in cell mitosis was discussed.

Antigenotoxic potential of plant leaf extracts of Parkinsonia aculeata L. using Allium cepa assay

The aim of the present study was to evaluate the antigenotoxic potential of P. aculeata L. leaf extract/fractions against maleic hydrazide (MH) using Allium cepa root chromosomal aberration assay. The excessive reduction in root growth and mitotic index value was observed after 3 h treatment of MH as compared to negative control (water). In case of MH treatment, frequency of aberrated cells significantly (p ≤ 0.05) raised from 129 to 337 at 0.1 ppm and 2.0 ppm concentrations respectively. From root growth inhibition test with MH treatment, EC₅₀ value i.e. 0.5 ppm was selected to study the antigenotoxic effect of different extract/fractions of P. aculeata L. leaves. All the extract/fractions showed increase in mitotic index and great reduction in chromosomal aberrations with rise in concentration against the genotoxicity of MH. Among all the extract/fractions, butanol and ethyl acetate fractions showed significant reduction in chromosomal aberrations in A. cepa cells and indicates the chemo preventive activity. Antigenotoxic property of this plant is due to the presence of various phytochemicals in leaf such as epi-orientin, Parkinsonin-A, Parkinsonin-B, orientin, iso-orientin, vitexin, iso-vitexin, C-glycosylflavone, parkintin, rotenoids, terpenoids, flavonoids, saponins, alkaloids, glycosides and anthraquinone etc. Our result showed that among all the treatments, simultaneous treatment showed best result followed by pre and post treatment. Further studies in animal model are suggested for further evaluation of the use of P. aculeata leaf extract in human welfare.

The effects of organophosphorus insecticides and heavy metals on DNA damage and programmed cell death in two plant models

The ubiquity of pollutants, such as agrochemicals and heavy metals, constitute a serious risk to human health. To evaluate the induction of DNA damage and programmed cell death (PCD), root cells of Allium cepa and Vicia faba were treated with two organophosphate insecticides (OI), fenthion and malathion, and with two heavy metal (HM) salts, nickel nitrate and potassium dichromate. An alkaline variant of the comet assay was performed to identify DNA breaks; the results showed comets in a dose-dependent manner, while higher concentrations induced clouds following exposure to OIs and HMs. Similarly, treatments with higher concentrations of OIs and HMs were analyzed by immunocytochemistry, and several structural characteristics of PCD were observed, including chromatin condensation, cytoplasmic vacuolization, nuclear shrinkage, condensation of the protoplast away from the cell wall, and nuclei fragmentation with apoptotic-like corpse formation. Abiotic stress also caused other features associated with PCD, such as an increase of active caspase-3-like protein, changes in the location of cytochrome C (Cyt C) toward the cytoplasm, and decreases in extracellular signal-regulated protein kinase (ERK) expression. Genotoxicity results setting out an oxidative via of DNA damage and evidence the role of the high affinity of HM and OI by DNA molecule as underlying cause of genotoxic effect. The PCD features observed in root cells of A. cepa and V. faba suggest that PCD takes place through a process that involves ERK inactivation, culminating in Cyt C release and caspase-3-like activation. The sensitivity of both plant models to abiotic stress was clearly demonstrated, validating their role as good biosensors of DNA breakage and PCD induced by environmental stressors.