Effects of the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate on the growth of wheat seedlings

Ecological risk of per-and polyfluorinated alkyl substances in the phytoremediation process: a case study for ecologically keystone species across two generations

The potential ecological risk of per- and polyfluorinated alkyl substances (PFASs) in phytoremediation has raised social concerns, promoting a need to better understand their distribution and risks in the recovery process of aquatic plants. Herein, we aim to fill this knowledge gap by investigating the distribution and ecotoxicological effects of PFASs on the structure and function of water-macrophyte-sediment microcosm systems. Among the entire system, 63.0 %-73.1 % PFOA was found in sediments and submerged plants, however, 52.5 %-53.0 % of PFPeA and 47.0 %-47.5 % of PFBS remained in the water under different treatments. PFOA was more bioavailable than the other substances, as demonstrated by the bioaccumulation factors (BAF) with ranges exposed to PFPeA and PFBS. Bioaccumulation PFASs induced plant oxidative stress which generates enzymes to suppress superoxide, and disturbed the processes of lysine biosynthesis, in which allysine, meso-2,6-diaminoheptanedioate, and Nsuccinyl-2-amino-6-ketopimelate were downregulated. PFASs were detected in the propagator (turions) of an ecological restoration species, where short-chain PFASs (70.1 % and 45.7 % for 2 or 20 μg/L PFAS exposure, respectively) were found to spread further into new individuals and profoundly influence ecological processes shaping populations. PFASs significantly enhanced the number of microbial species in the sediment, but the degree of differentiation in the microbial community structure was not significantly different. This study enhances our understanding of the ecological mechanisms of PFASs in the water-macrophyte-sediment systems and potential threats to the recovery process of macrophytes.

Thiocyanate-degrading microflora alleviates thiocyanate stress on tomato seedlings by improving plant and rhizosphere microenvironment

Thiocyanate in irrigation water can adversely affect plant growth and development. A previously constructed microflora with effective thiocyanate-degrading ability was used to investigate the potential of bacterial degradation for thiocyanate bioremediation. The root and aboveground part dry weight of plants inoculated with the degrading microflora increased by 66.67% and 88.45%, respectively, compared to those plants without the microflora. The supplementation of thiocyanate-degrading microflora (TDM) significantly alleviated the interference of thiocyanate in mineral nutrition metabolism. Moreover, the supplementation of TDM significantly reduced the activities of antioxidant enzymes, lipid peroxidation, and DNA damage and it protected plants from excessive thiocyanate, while the crucial antioxidant enzyme (peroxidase) decreased by 22.59%. Compared with the control without TDM supplementation, the soil sucrase content increased by 29.58%. The abundances of Methylophilus, Acinetobacter, unclassified Saccharimonadales, and Rhodanobacter changed from 19.92%, 6.63%, 0.79%, and 3.90%-13.19%, 0.27%, 3.06%, and 5.14%, respectively, with TDM supplementation. Caprolactam, 5,6-dimethyldecane, and pentadecanoic acid seem to have an effect on the structure of the microbial community in the rhizosphere soil. The above results indicated TDM supplementation can significantly reduce the toxic effects of thiocyanate on the tomato-soil microenvironment.

Effects of [Cnpy]Br (n=3,5) on the growth and physiology of rape seedlings

1-Alkylpyridinium bromide [C_npy]Br is a common intermediate in chemical synthesis. With the discharge of industrial wastewater, it enters the environment and is toxic to plants. In this study, the impacts of two pyridine-based ionic liquids (ILs), [C₃py]Br and [C₅py]Br, on the growth and physiology of rape seedlings were investigated at concentrations of 10, 50, 100, 200, 300, and 400 mg/L. Within the concentration range (10-400 mg/L) of [C₃py]Br and [C₅py]Br treatment, the root length, plant height, activities of antioxidant enzymes (SOD, POD, and CAT), and the contents of Chla and Chlb showed an increase at low concentrations and a decrease at high concentrations. [C₃py]Br and [C₅py]Br increased MDA content in rape seedlings leaves in a concentration-dependent manner. It was also found that [C₅py]Br was more toxic to rape seedlings than [C₃py]Br. The toxicity of pyridine ILs such as [C₃py]Br and [C₅py]Br to plants should be highly concerned.

Curbing per- and polyfluoroalkyl substances (PFASs): First investigation in a constructed wetland-microbial fuel cell system

The presence of per- and polyfluoroalkyl substances (PFASs) in water environments has been linked to a slew of negative health effects in both animals and humans, but the green and eco-sustainable removal technologies remain largely unknown. Constructed wetland coupled microbial fuel cell (CW-MFC) is termed a "green process" to control pollutants and recover energy. However, so far, no study has investigated the removal of PFASs and their effects on the performance of the CW-MFC systems. Here, we investigated the removal performance of PFOA and PFOS in the CW-MFC systems both in the absence and presence of electricity circuit, and explored the distribution and fate of PFASs and their interactions with other elements in the systems. Our findings demonstrated excellent removal efficiency of >96% PFOA and PFOS in CW-MFC systems. PFOA and PFOS were distributed throughout the system via wastewater flow, while electrode material and plants are the main enrichment sites in which MFC enhanced up to 10% PFASs removal. However, a loss of 7.2-13.5% of nitrogen removal and a decrease of 7.3% in bioelectricity output were observed when PFASs were introduced in the system. The driven force led to the loss of nitrogen removal and bioelectricity generation lies in the accumulation of PFASs in system composition, which affected microbial activity and community composition, damaging the health of the plant, and in turn reducing CW-MFC's functioning. No doubt, CW-MFC systems provide an alternative technique for PFASs removal, alleviating some limitations to the physical and chemical techniques, but further investigation is highly needed.

Removal potential of multiple perfluoroalkyl acids (PFAAs) by submerged macrophytes in aquatic environments: Tolerance of Vallisneria natans and PFAA removal in submerged macrophyte-microbiota systems

Perfluoroalkyl acids (PFAAs) have emerged as a global concern in aquatic environment remediation due to their abundance, persistence, bioaccumulation, and toxicity. To comprehensively understand the removal potential of multiple PFAAs by submerged macrophytes in aquatic environments, systematic investigations into the tolerance of the typical submerged macrophyte Vallisneria natans to 12 typical PFAAs and the removal capacity to PFAAs in V. natans-microbiota systems were carried out. Results showed that although PFAAs could induce the accumulation of hydrogen peroxide and malondialdehyde, V. natans was overall resistant to multiple PFAAs with natural concentrations. Catalase is one of the main strategies of V. natans to alleviate PFAA stress. Microbiota can remove 18.10-30.84% of the PFAAs from the water column. 24.35-73.45% of PFAAs were removed from water in V. natans-microbiota systems. The uptake of plant tissues and the bioaccumulation of microbiota were proposed as the main removal processes. The removal rates were significantly correlated with the perfluorinated carbon atoms numbers (p < 0.05). PFAAs and V. natans increased the relative abundance of Betaproteobacteria, Nostocales, Microscillaceae, Sphingobacteriales, SBR1031, Chlamydiales, Phycisphaerae, Caldilineales, Rhodobacterales, and Verrucomicrobiales. The present study suggested that V. natans can be a potential species to remove multiple PFAAs in aquatic environments, and further providing insights into the PFAAs' remediation.

Reaction of spring barley seedlings and H. incongruens crustaceans to the presence of acetylsalicylic acid in soil

Acetylsalicylic acid (ASA) is one of the more commonly used analgesic, antipyretic, and anti-inflammatory as well as anticoagulant drugs available in the OTC (over the counter) segment. Due to the considerable use of this drug, an attempt was made to determine the effect of ASA on the crustacean Heterocypris incongruens and the monocotyledonous plant spring barley. The tested compounds were introduced into soil in which these organisms "lived". The study showed that ASA had an adverse effect on seed germination potential as well as a negative effect on spring barley growth; however, and photosynthetic pigments content was observed only at the highest concentrations of the studied compounds. ASA did not cause oxidative stress in plants but did also cause disturbances in the growth of H. incongruens, without causing their mortality. As a result, ASA may have certain negative effects on both crustaceans and monocots.

Effect of diclofenac and naproxen and their mixture on spring barley seedlings and Heterocypris incongruens

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a popular group of drugs used worldwide. These drugs are also available over the counter, which implies that their consumption is not strictly regulated. They are released through wastewater and feces and can have adverse effects on the environment. The present study aimed to evaluate the effect of two NSAIDs, diclofenac (DCF) and naproxen (NAP), and their mixture (DCF + NAP) on spring barley seedlings and ostracods Heterocypris incongruens. The tested drugs had a negative impact on bivalve ostracods and the studied plants. DCF was the most toxic toward ostracods, while spring barley seedlings were affected the most by NAP. The application of the tested compounds and their mixture resulted in a decrease in fresh weight yield and the content of photosynthetic pigments. In addition, an increase in H₂O₂ and proline content and changes in the activity of antioxidant enzymes (POD, APX, CAT, and SOD) were observed.

Review of the toxic effects of ionic liquids

Interest in ionic liquids (ILs), called green or designer solvents, has been increasing because of their excellent properties such as thermal stability and low vapor pressure; thus, they can replace harmful organic chemicals and help several industrial fields e.g., energy-storage materials production and biomaterial pretreatment. However, the claim that ILs are green solvents should be carefully considered from an environmental perspective. ILs, given their minimal vapor pressure, may not directly cause atmospheric pollution. However, they have the potential to cause adverse effects if leaked into the environment, for instance if they are spilled due to human mistakes or technical errors. To estimate the risks of ILs, numerous ILs have had their toxicity assessed toward several micro- and macro-organisms over the past few decades. Since the toxic effects of ILs depend on the method of estimating toxicity, it is necessary to briefly summarize and comprehensively discuss the biological effects of ILs according to their structure and toxicity testing levels. This can help simplify our understanding of the toxicity of ILs. Therefore, in this review, we discuss the key findings of toxicological information of ILs, collect some toxicity data of ILs to different species, and explain the influence of IL structure on their toxic properties. In the discussion, we estimated two different sensitivity values of toxicity testing levels depending on the experiment condition, which are theoretical magnitudes of the inherent sensitivity of toxicity testing levels in various conditions and their changes in biological response according to the change in IL structure. Finally, some perspectives, future research directions, and limitations to toxicological research of ILs, presented so far, are discussed.

Reduced phytotoxicity of nonylphenol on tomato (Solanum lycopersicum L.) plants by earthworm casts

Concentrations as high as thousands of milligrams per kilogram (dry weight) of nonylphenol (NP), an endocrine-disrupting chemical of great concern, have been reported in soil. Soil is considered one of the primary pathways for exposure of crop plants to NP. However, there have been few studies on the toxicity of soil NP to crop plants, especially with comprehensive consideration of the application of organic fertiliser which is a common agricultural practice. In this study, tomato plants were grown in soils treated with NP in the presence and/or absence of earthworm casts (EWCs). After four weeks, we tested the physiological and biochemical responses (accumulative levels of hydrogen peroxide (H₂O₂) and superoxide anion radicals (O₂-·), total chlorophyll content, degree of membrane lipid peroxidation, activities of defence-related enzymes, and level of DNA damage) and the changes in plant growth (elongation and biomass). The growth inhibition, reactive oxygen species (H₂O₂ and O₂-·) accumulation, decrease in chlorophyll content, increase in activity of defence-related enzymes (including superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione S-transferase and glutathione reductase), enhancement of membrane lipid peroxidation, and DNA damage in NP-treated seedlings were clearly reversed by the intervention of EWCs. In particular, the suppressed elongation, biomass, and chlorophyll content in tomato plants exposed to NP alone were significantly restored by EWCs to even greater levels than those of the undisturbed control. In other words, EWCs could efficiently invigorate the photosynthesis of crops via up-regulating the chlorophyll content, thereby overwhelming the NP stress on plant growth. Accordingly, except for reducing the bioavailability of soil NP as reported in our previous study, EWCs could also help crop plants to cope with NP stress by strengthening their stress resistance ability. Our findings are of practical significance for the formulation of strategies to relieve the negative effects of soil NP on crop growth.

Renal injury and hepatic effects from the methylimidazolium ionic liquid M8OI in mouse

The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identified as a hazard for triggering the liver disease primary biliary cholangitis (PBC). Given limited toxicity data for M8OI and other structurally-related ionic liquids, target organs for M8OI toxicity were examined. Adult male C57Bl6 mice were acutely exposed to 0-10 mg/kg body weight M8OI via 2 intraperitoneal injections (time zero and 18 h) and effects examined at 24 h. At termination, tissue histopathology, serum and urinary endpoints were examined. No overt pathological changes were observed in the heart and brain. In contrast, focal and mild to multifocal and moderate degeneration with a general trend for an increase in severity with increased dose was observed in the kidney. These changes were accompanied by a dose-dependent increased expression of Kim1 in kidney tissue, marked elevations in urinary Kim1 protein and a dose-dependent increase in serum creatinine. Hepatic changes were limited to a significant dose-dependent loss of hepatic glycogen and a mild but significant increase in portal tract inflammatory recruitment and/or fibroblastic proliferation accompanied by a focal fibrotic change. Cultured mouse tissue slices reflected these in vivo effects in that dose-dependent injury was observed in kidney slices but not in the liver. Kidney slices accumulated higher levels of M8OI than liver slices (e.g. at 10 μM, greater than 4 fold) and liver slices where markedly more active in the metabolism of M8OI. These data indicate that the kidney is a target organ for the toxic effects of M8OI accompanied by mild cholangiopathic changes in the liver after intraperitoneal administration.

Mechanisms of action of ionic liquids on living cells: the state of the art

Ionic liquids (ILs) are a relatively new class of organic electrolytes composed of an organic cation and either an organic or inorganic anion, whose melting temperature falls around room-temperature. In the last 20 years, the toxicity of ILs towards cells and micro-organisms has been heavily investigated with the main aim to assess the risks associated with their potential use in (industrial) applications, and to develop strategies to design greener ILs. Toxicity, however, is synonym with affinity, and this has stimulated, in turn, a series of biophysical and chemical-physical investigations as well as few biochemical studies focused on the mechanisms of action (MoAs) of ILs, key step in the development of applications in bio-nanomedicine and bio-nanotechnology. This review has the intent to present an overview of the state of the art of the MoAs of ILs, which have been the focus of a limited number of studies but still sufficient enough to provide a first glimpse on the subject. The overall picture that emerges is quite intriguing and shows that ILs interact with cells in a variety of different mechanisms, including alteration of lipid distribution and cell membrane viscoelasticity, disruption of cell and nuclear membranes, mitochondrial permeabilization and dysfunction, generation of reactive oxygen species, chloroplast damage (in plants), alteration of transmembrane and cytoplasmatic proteins/enzyme functions, alteration of signaling pathways, and DNA fragmentation. Together with our earlier review work on the biophysics and chemical-physics of IL-cell membrane interactions (Biophys. Rev. 9:309, 2017), we hope that the present review, focused instead on the biochemical aspects, will stimulate a series of new investigations and discoveries in the still new and interdisciplinary field of "ILs, biomolecules, and cells."

Phytotoxicity and Effect of Ionic Liquids on Antioxidant Parameters in Spring Barley Seedlings: The Impact of Exposure Time

The influence of the ionic liquids (ILs) tetrabutylammonium bromide [TBA][Br], 1-butyl-3-methylimidazole bromide [BMIM][Br], and tetrabutylphosphonium bromide [TBP][Br] added at different concentrations to the soil were studied for the growth and development of spring barley seedlings. Samples were harvested at three different time points: day 7, 14, and 21 after addition of ILs. The results show that [TBP][Br] was the most toxic. The introduction of this IL at the dose of 100 mg kg−1 of soil DM decreased the growth of seedlings at all test dates. The addition of the studied ILs to the soil in higher doses resulted in an increase in peroxidase and catalase activity, which may indicate the occurrence of oxidative stress in plants. An increase in the content of plant dry matter weight, contents of H2O2 and proline and a decrease in the content of photosynthetic pigments in barley seedlings were also observed. The malondialdehyde content and superoxide dismutase activity fluctuated randomly during the experiment. As a result, it was found that the phytotoxicity of ILs and the magnitude of oxidative stress in seedlings depended more on the added doses of these compounds than on the measurement date.

The reaction of cucumber to the introduction of ionic liquids into the soil

This paper presents the influence of two bromides, tetrabutylammonium and tetrabutylphosphonium, on the growth and development of cucumber seedlings. The tests were performed at two dates, i.e. 10 and 20 days, after the introduction of increasing amounts of ionic liquids (ILs) into the soil. The applied ILs showed phytotoxicity dependent mainly on the concentration of the substance, which is proved by the inhibition of the length of aboveground parts and their roots and the yield of cucumber fresh mass, from which EC50 values were calculated. The phytotoxicity symptoms were the result of oxidative stress, one of the manifestations of which was a decrease in assimilative pigments, linearly correlated with an increase in bromide concentration in the medium. The stress is also proven by the large increase in hydrogen peroxide, malondialdehyde and free proline in cucumber leaves. The reaction of this plant to oxidative stress was an increase in the activity of antioxidative enzymes such as catalase and peroxidase. As a result of statistical analysis, it was proved that all changes of biomarkers of phytotoxicity of examined ILs and oxidative stress indicators in cucumber seedlings depended more on the applied concentration of these salts than on the date of the study.

Toxic effect of three imidazole ionic liquids on two terrestrial plants

To determine the toxic effect of three imidazole ionic liquids (IILs) in terrestrial monocotyledonous and dicotyledonous plants, three IILs (1-butyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole hexafluorophosphate, and butyl-3-methylimidazolium bi-[(trifluoromethyl)sulfonyl]imide) were investigated using rice and capsicum as target toxicity models. In hydroponic experiments, increasing the concentration of the IILs led to a decrease in the seed germination rate, a decrease in the reduced stem and root lengths, and an increase in the inhibition rate of the stem and root lengths; in addition, as the concentration increased, the reducing sugar content of rice and capsicum seedling leaves and roots first increased and then decreased, while permeability of the cell membranes of the stems and roots of the two plants also gradually increased. In terms of the effects on these indices in rice, the ranking of these three IIL anions was [TF2N]- > [PF6]- > [BF4]-; in terms of the effects on capsicum, the sequence was [BF4]- > [TF2N]- > [PF6]-. These findings provide a theoretical reference for the next step in the synthesis and the use of green ionic liquids.

Changes in the gut microbiota of mice orally exposed to methylimidazolium ionic liquids

Ionic liquids are salts used in a variety of industrial processes, and being relatively non-volatile, are proposed as environmentally-friendly replacements for existing volatile liquids. Methylimidazolium ionic liquids resist complete degradation in the environment, likely because the imidazolium moiety does not exist naturally in biological systems. However, there is limited data available regarding their mammalian effects in vivo. This study aimed to examine the effects of exposing mice separately to 2 different methylimidazolium ionic liquids (BMI and M8OI) through their addition to drinking water. Potential effects on key target organs-the liver and kidney-were examined, as well as the gut microbiome. Adult male mice were exposed to drinking water containing ionic liquids at a concentration of 440 mg/L for 18 weeks prior to examination of tissues, serum, urine and the gut microbiome. Histopathology was performed on tissues and clinical chemistry on serum for biomarkers of hepatic and renal injury. Bacterial DNA was isolated from the gut contents and subjected to targeted 16S rRNA sequencing. Mild hepatic and renal effects were limited to glycogen depletion and mild degenerative changes respectively. No hepatic or renal adverse effects were observed. In contrast, ionic liquid exposure altered gut microbial composition but not overall alpha diversity. Proportional abundance of Lachnospiraceae, Clostridia and Coriobacteriaceae spp. were significantly greater in ionic liquid-exposed mice, as were predicted KEGG functional pathways associated with xenobiotic and amino acid metabolism. Exposure to ionic liquids via drinking water therefore resulted in marked changes in the gut microbiome in mice prior to any overt pathological effects in target organs. Ionic liquids may be an emerging risk to health through their potential effects on the gut microbiome, which is implicated in the causes and/or severity of an array of chronic disease in humans.

Toxicity Evaluation of Three Imidazolium-based ionic liquids ([C6mim]R) on Vicia faba Seedlings Using an integrated biomarker response (IBR) index

Ionic liquids (ILs) are regarded as green solvents and are frequently used in the chemical industry. However, ILs may impact plant growth if they are present in the soil environment. To compare toxicity of ILs with different anions in soil, three imidazolium-based ionic liquids (1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium nitrate, 1-hexyl-3-methylimidazolium tetrafluoroborate) were used to assess impact on Vicia faba. Following 10 d of exposure to these three ILs from 0 to 2500 mg kg^-1, shoot length, root length and dry weight of Vicia faba were determined. Pot trials revealed that ILs inhibited Vicia faba growth and according to EC₅₀ values, [C₆mim]BF₄ was the most toxic one. In addition, physiological indicators of Vicia faba were determined following 10 d of exposure at selected IL concentrations (0, 1, 10, 100 and 500 mg kg^-1). ILs led to the generation of reactive oxygen species and then caused oxidative damage, including lipid peroxidation, protein damage and DNA damage, which triggered an increase in antioxidant content and enzyme activity. The experimental results indicated that oxidative stress may be the primary underlying toxic mechanism for Vicia faba. Furthermore, based on the data of physiological experiment, integrated biomarker response (IBR) was calculated to compare the toxicity of the three ILs and toxic order was: [C₆mim]NO₃＜[C₆mim]Br＜[C₆mim]BF_4.

The toxicity of the methylimidazolium ionic liquids, with a focus on M8OI and hepatic effects

Ionic liquids are a diverse range of charged chemicals with low volatility and often liquids at ambient temperatures. This characteristic has in part lead to them being considered environmentally-friendly replacements for existing volatile solvents. However, methylimidazolium ionic liquids are slow to break down in the environment and a recent study at Newcastle detected 1 octyl 3 methylimidazolium (M8OI) - an 8 carbon variant methylimidazolium ionic liquid - in soils in close proximity to a landfill site. The current M8OI toxicity database in cultured mammalian cells, in experimental animal studies and in model indicators of environmental impact are reviewed. Selected analytical data from the Newcastle study suggest the soils in close proximity to the landfill site, an urban soil lacking overt contamination, had variable levels of M8OI. The potential for M8OI - or a structurally related ionic liquid - to trigger primary biliary cholangitis (PBC), an autoimmune liver disease thought to be triggered by an unknown agent(s) in the environment, is reviewed.

Phytotoxicity of ionic liquids

Ionic liquids (ILs) have been one of the most interesting chemical entities over the last two decades and have been investigated by numerous scientists all over the world. However, during IL research, it has been shown that these compounds present toxicity to both terrestrial and aquatic plants, among others. The phytotoxicity of ILs depends on the type of cation, the length of the alkyl chain in the substituent or enantioselectivity, on the concentration used, and, it appears that the type of anion may also have an impact on toxicity. The toxic effects of ILs on plants also depend on the conditions under which such tests are conducted. The results may help facilitate the development of protective environmental measures against IL-induced negative effects, but they may also be used in various landscape-related areas, such as herbology, to design new substances with weed killing properties.

Phytotoxicity and oxidative stress of perfluorooctanesulfonate to two riparian plants: Acorus calamus and Phragmites communis

Despite previous efforts and the rapid progress on elucidating the impact of perfluorooctanesulfonate (PFOS) on the environment, its effects on riparian plants, a key component of aquatic ecosystems, are still poorly understood. A 48-day hydroponic experiment was carried out on two typical riparian species (Acorus calamus and Phragmites communis) to examine the toxic effects of PFOS on these plants. The results showed that, at high concentration (more than 10 mg L^-1), PFOS could prevent chlorophyll accumulation (reduced by 13.7-22.2% at 10 mg L^-1 PFOS and 22.4-30.0% at 50 mg L^-1 PFOS for 48 days) and soluble protein synthesis (reduced by 2.3-9.0% at 10 mg L^-1 PFOS and 10.6-26.8% at 50 mg L^-1 PFOS for 48 days). Contrastingly, less than 1 mg L^-1 of PFOS could induce chlorophyll accumulation (increased by 18.6% in A. calamus roots, 11.3% in A. calamus leaves, and 13.6% in P. communis roots at 1 mg L^-1 PFOS for 3 days) and soluble protein synthesis (increased by 6.1% in A. calamus roots, 18.4% in A. calamus leaves, 9.7% in P. communis roots, 23.4% in P. communis stems, and 24.0% in P. communis leaves, at 1 mg L^-1 PFOS for 6 days). In addition, PFOS led to oxidative stress, as revealed by the elevated concentrations of malonaldehyde and hydrogen peroxide, and reduced the activities of antioxidant enzymes such as superoxide dismutase (reduced by 10.3% in P. communis stems at 50 mg L^-1 PFOS for 48 days), catalase (reduced by 20.6-50.3% in test species at 50 mg L^-1 PFOS for 48 days), and peroxidase (reduced by 24.9-37.7% in test species at 50 mg L^-1 PFOS for 48 days). The biomarkers of both plants changed rapidly in the first half of the experiment (0-24 days) and stabilized in the second half of the experiment (24-48 days). The risk and related factors of PFOS on riparian plants were evaluated by using these biomarkers. Experiments showed that P. communis was more resistant to low concentration (<10 mg L^-1) of PFOS than A. calamus.

Use of Ganoderma Lucidum polysaccharide to control cotton fusarium wilt, and the mechanism involved

Induced resistance is an effective measure for controlling plant diseases by utilizing the natural defense of the host and meets the strategic needs of pesticide application and safety for agricultural products worldwide. Ganoderma lucidum polysaccharide (GLP), which is the main active molecule of G. lucidum, has been widely used in functional food and clinical medicine. However, there are few reports of the use of GLP for the prevention and control of plant diseases. The purpose of this study is to explore the effect of GLP and its mechanism of inducing plant resistance. In this study, we found that GLP spray and irrigation root treatments can promote growth in cotton. After soaking in GLP, theseedling height and cotton fusarium wilt resistance both increased to some extent, effects that were dose dependent. After treatment of cotton with GLP, the activities of peroxidase (POD), superoxide dismutase (SOD) and polyphenol oxidase (PPO) in leaves increased significantly, whereas the content of malondialdehyde (MDA) decreased. In addition, QRT-PCR results showed significantly increased relative expression of genes related to the jasmonic acid pathway in cotton. Therefore, we speculate that GLP can induce plant resistance by stimulating the jasmonate pathway.

Bioaccumulation and toxicity of pentachloronitrobenzene to earthworm (Eisenia fetida)

Pentachloronitrobenzene (PCNB) has been widely utilized as a fungicide to control diseases. However, toxic effect data of PCNB on terrestrial invertebrate are not available till now. Herein, the earthworms (Eisenia fetida) were exposed to soil containing different levels of PCNB. Mortality, weight, accumulation, and physiological indexes of earthworms were determined on certain days. PCNB inhibited the growth of earthworms and induced a significant increase in the activity of antioxidative enzymes. ROS, SOD, and MDA of earthworms in the highest treatment group were 6.8, 4.4, and 3.8 times higher than those in the control group, respectively. In addition, earthworm coelomocytes were successfully extracted, cultured, and innovatively employed in in-vitro toxicity test to evaluate the toxic effect of PCNB. The biomarkers utilized in in-vitro toxicity test, including cell viability, intracellular ROS and extracellular LDH showed significant correlations with the PCNB in the culture media, indicating that the in-vitro toxicity test may serve as a useful tool for toxic assessment of pollutants to earthworms and other organisms.

Biochemical Responses of Wheat Seedlings on the Introduction of Selected Chiral Ionic Liquids to the Soils

In this study, new chiral ionic liquids (CILs) were obtained from the natural-origin material (1 R,2 S,5 R)-(-)-menthol. The physicochemical characteristics of the studied imidazolium salts were investigated. The obtained 3-ethyl-1-[(1 R,2 S,5 R)-(-)-menthoxy-methyl]imidazolium salts are nonvolatile, nonflammable, and stable in air, in contact with water, and in commonly used organic solvents. The influences of the obtained chiral salts on physiological and biochemical parameters were determined for wheat ( Triticum aestivum L.) seedlings. Both salts led to changes in plant metabolism, which resulted in decreased assimilation pigments, decreased fresh weight, and increased dry weight and proline in wheat seedlings. Moreover, the growth of the above-ground parts and roots was inhibited. Additionally, there was a drop in the potential and germination capacity of wheat seeds after using the highest concentrations of the ionic liquids. The salts caused oxidative stress in wheat seedlings, which was demonstrated by increased malondialdehyde content. In response, the plants engaged their defensive system against free oxygen radicals, which resulted in increased catalase and peroxidase activity and decreased H₂O₂ levels in the plants. There were no changes in the activity of superoxide dismutase. All of the changes observed in the levels of determined biomarkers of oxidative stress in the plants were linearly correlated with the increase in the concentrations of the chiral ionic liquids in the soil. The salt with hexafluorphosphate anion exhibited slightly higher toxicity toward wheat seedlings than the other salt. The CILs led to premature aging of plants, which was demonstrated by the increase in peroxidase activity and a decrease of chlorophyll in the seedlings. The experiment also showed good correlation between the increase in peroxidase activity and the decrease in chlorophyll level, which proves that the decrease in chlorophyll content resulted from not only the increase in CILs concentration in the soil but also the increased POD activity, which leads to the damage of chlorophyll particles.

CRISPR/Cas9-Mediated SlNPR1 mutagenesis reduces tomato plant drought tolerance

BACKGROUND

NPR1, nonexpressor of pathogenesis-related gene 1, is a master regulator involved in plant defense response to pathogens, and its regulatory mechanism in the defense pathway has been relatively clear. However, information about the function of NPR1 in plant response to abiotic stress is still limited. Tomato is the fourth most economically crop worldwide and also one of the best-characterized model plants employed in genetic studies. Because of the lack of a stable tomato NPR1 (SlNPR1) mutant, little is known about the function of SlNPR1 in tomato response to biotic and abiotic stresses.

RESULTS

Here we isolated SlNPR1 from tomato 'Ailsa Craig' and generated slnpr1 mutants using the CRISPR/Cas9 system. Analysis of the cis-acting elements indicated that SlNPR1 might be involved in tomato plant response to drought stress. Expression pattern analysis showed that SlNPR1 was expressed in all plant tissues, and it was strongly induced by drought stress. Thus, we investigated the function of SlNPR1 in tomato-plant drought tolerance. Results showed that slnpr1 mutants exhibited reduced drought tolerance with increased stomatal aperture, higher electrolytic leakage, malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels, and lower activity levels of antioxidant enzymes, compared to wild type (WT) plants. The reduced drought tolerance of slnpr1 mutants was further reflected by the down-regulated expression of drought related key genes, including SlGST, SlDHN, and SlDREB.

CONCLUSIONS

Collectively, the data suggest that SlNPR1 is involved in regulating tomato plant drought response. These results aid in further understanding the molecular basis underlying SlNPR1 mediation of tomato drought sensitivity.

Evaluation of the impact of different alkyl length and type of substituent in imidazolium ionic liquids on cucumber germination, growth and oxidative stress

In this work, the effect on cucumber growth of seven different imidazolium-based ionic liquids, namely 1-(2-oxybutyl)-3-methylimidazolium chloride, [C₂OC₂mIm][Cl]; 1-(2-oxypropyl)-3-methylimidazolium chloride, [C₁OC₂mIm][Cl]; 1-(3-hydroxypropyl)-3-ethylimidazolium chloride, [OHC₃eIm][Cl]; 1-(3-hydroxypropyl)-3-methylimidazolium chloride, [OHC₃mIm][Cl]; 1-(2-hydroxyethyl)-3-methylimidazolium chloride, [OHC₂mIm][Cl], 1-butyl-3-methylimidazolium chloride, [bmim][Cl] and imidazolium chloride, [Im][Cl], were examined. The influence of polarity of the alkyl side chain of the imidazolium cation on the reduction of the ionic liquid's toxicity is investigated. For all investigated seedlings, significant reduction of biomass was noted, with the incoherent influence of the ionic liquid (IL) concentration. The total inhibition of germination was shown at the highest used concentration for some of the used ionic liquids. Although investigated ILs affected root and shoot growth of cucumber, the effect on stress marker (MDA) as well as biosynthesis of chlorophyll and carotenoids was negligible. The data collected in this research suggest that tuning of the lipophilicity of imidazolium cations by the introduction of polar groups in the side alkyl chain does not have pronounced effect on cucumber, as it was shown for other plant species.

Evaluating toxicity of 1-octyl-3-methylimidazolium hexafluorophosphate to microorganisms in soil

Ionic liquids (ILs) were widely applied because of their excellent properties. The present investigation studied the toxicity of the IL 1-octyl-3-methylimidazolium hexafluorophosphate ([Omim]PF₆) to the soil microbial population and community diversity with dose (1.0, 2.0, 4.0, 6.0, and 8.0 mg kg^-1) and exposure time (7, 10, and 13 d). The results show the IL was stable during the entire experimental period. The Biolog-ECO plate results indicated that the average well color development (AWCD) in the 6.0 and 8.0 mg kg^-1 treatments was lower than these in the other treatments. The diversity indices of the Biolog analysis were significantly reduced. The abundance of the ammonia-oxidizing archaea (AOA-) and the ammonia-oxidizing bacteria (AOB-) ammonia monooxygenase (amoA) genes was measured by the real-time polymerase chain reaction (RT-PCR). In the treatments of 4.0, 6.0 and 8.0 mg kg^-1, the abundance of amoA genes of the AOA- and AOB- were inhibited by IL [Omim]PF₆.

Reduction of Tomato-Plant Chilling Tolerance by CRISPR-Cas9-Mediated SlCBF1 Mutagenesis

Chilling stress is the main constraint in tomato ( Solanum lycopersicum) production, as this is a chilling-sensitive horticultural crop. The highly conserved C-repeat binding factors (CBFs) are cold-response-system components found in many species. In this study, we generated slcbf1 mutants using the CRISPR-Cas9 system and investigated the role of SlCBF1 in tomato-plant chilling tolerances. The slcbf1 mutants exhibited more severe chilling-injury symptoms with higher electrolyte leakage and malondialdehyde levels than wild-type (WT) plants. Additionally, slcbf1 mutants showed lower proline and protein contents and higher hydrogen peroxide contents and activities of antioxidant enzymes than WT plants. Knockout of SlCBF1 significantly increased indole acetic acid contents but decreased methyl jasmonate, abscisic acid, and zeatin riboside contents. The reduced chilling tolerance of the slcbf1 mutants was further reflected by the down-regulation of CBF-related genes. These results contribute to a better understanding of the molecular basis underlying SlCBF1 mediation of tomato chilling sensitivity.

Assessing the influence of 1-dodecyl-3-methylimidazolium chloride on soil characteristics and Vicia faba seedlings

Imidazolium-based ionic liquids (ILs) have attracted increasing attention in recent years. The IL 1-dodecyl-3-methylimidazolium chloride ([C₁₂mim]Cl) has been widely used in the chemical industry. In this study, the influence of [C₁₂mim]Cl on Vicia faba seedlings, soil physicochemical properties and soil enzyme activities was investigated for the first time. Meanwhile, the variation of [C₁₂mim]Cl concentrations in soil was monitored during the exposure period. The present results showed that the concentration of [C₁₂mim]Cl remained stable in the tested soil with a change rate of no more than 10% during the exposure period. The 50% effective concentration (EC₅₀) values for shoot length, root length and dry weight were 188, 69 and 132 mg kg^-1, respectively. At 200 mg kg^-1 and 400 mg kg^-1, [C₁₂mim]Cl had significant influence on soil organic matter content, pH value and conductivity value. At 40 mg kg^-1, the reactive oxygen species (ROS) levels were obviously enhanced, resulting in oxidative stress effects in Vicia faba seedling leaves. Additionally, the soil enzyme activities changed significantly at 40 mg kg^-1.

Growth, reproduction and biochemical toxicity of chlorantraniliprole in soil on earthworms (Eisenia fetida)

Diamide insecticides have become the fourth most commonly used insecticide class in the world. Chlorantraniliprole (CAP) is a first-generation diamide insecticide with broad application potential. In this experiment, the eco-toxicity of CAP in soil at 0.1, 1.0, 5.0 and 10.0mg/kg on earthworms (Eisenia fetida) was evaluated during a 42 d exposure. More specifically, the environmental fate and transport of CAP between soil and earthworms was monitored during the exposure period. The present results indicated that the CAP contents of 0.1, 1.0, 5.0 and 10.0mg/kg treatments decreased to no more than 20% in the soil after 42 d of exposure. The accumulation of CAP in earthworms was 0.03, 0.58, 4.28 and 7.21mg/kg earthworm (FW) at 0.1, 1.0, 5.0 and 10.0mg/kg after 42 d of exposure. At 0.1mg/kg and 1.0mg/kg, CAP had no effect on earthworms during the exposure period. The weight of earthworms was significantly reduced at 5.0 and 10.0mg/kg at 28 and 42 days after CAP application. After the 14th day, CAP induced excess production of reactive oxygen species (ROS) at 5.0 and 10.0mg/kg, resulting in oxidative damage to biomacromolecules. We believe that CAP has a high risk potential for earthworms when used at 5.0 and 10.0mg/kg.

Imidazolium and benzimidazolium-containing compounds: from simple toxic salts to highly bioactive drugs

The toxicity of simple imidazolium and benzimidazolium salts started to be more and more investigated in the last few years and was taken in consideration in the context of microorganisms, plants and more evolved organisms' exposure. However, the toxicity of these salts can be exploited in the development of different biological applications by incorporating them in the structure of compounds that specifically target microorganisms and cancer cells. We highlight in this minireview the way researchers became aware of the inherent problem of the stability and bioaccumulation of imidazolium and benzimidazolium salts and how they found inspiration to exploit their toxicity by incorporating them into new highly potent drugs.

Physiological and biochemical responses of wheat (Triticum aestivum L.) seedlings to three imidazolium-based ionic liquids in soil

Ionic liquids (ILs) are considered environmentally friendly solvents and are widely applied in various fields; however, some researchers have noted the toxicity of ILs to plants cultivated in nutrient solution. To evaluate the toxicities of ILs to wheat seedlings in soil, the natural growth environment of plants, a study was performed using three imidazolium-based ionic liquids with different anions: 1-octyl-3-methylimidazolium chloride ([C₈mim]Cl), 1-octyl-3-methylimidazolium bromide ([C₈mim]Br) and 1-octyl-3-methylimidazolium tetrafluoroborate ([C₈mim]BF₄). After 13 d of exposure to these three ILs at 0, 100, 200, 400, 600 and 800 mg kg^-1 in brown soil, wheat seedlings were randomly sampled to evaluate growth (shoot length, root length, pigment content and proline content), lipid peroxidation, oxygen species (H₂O₂ and O₂^-) and activities of the detoxification enzyme glutathione-s-transferase and other antioxidant enzymes, including superoxide dismutase, catalase and peroxidase. The experimental results showed that all three ILs had inhibitory effects on the growth of wheat seedlings and induced the generation of reactive oxygen species, which indicated that the wheat seedlings suffered oxidative stress. Moreover, antioxidant enzyme activity was enhanced after exposure to [C₈mim]Cl, [C₈mim]Br and [C₈mim]BF₄, demonstrating that oxidative damage may be the primary underlying mechanism of IL toxicity in wheat.

Use of Lentinan To Control Sharp Eyespot of Wheat, and the Mechanism Involved

Lentinan (LNT), a complex polysaccharide with a β-(1→3)-linked backbone of d-glucose residues, has been reported to inhibit plant diseases. Our objective was to explore the efficacy and action mechanism of LNT used as a seed dressing to control sharp eyespot of wheat. Seed dressing promoted wheat growth. At control germination rates of 50%, 8 g of LNT/100 kg of seeds of the Jimai 22, Shannong 23, and Luyuan 502 cultivars significantly increased seed germination to 54%, 52%, and 51%, respectively. Seven days after emergence, the heights and root activity of wheat treated with LNT were significantly greater than those of controls. These effects were dose-dependent. At this time, the plant heights of Jimai 22, Shannong 23, and Luyuan 502 cultivars were 9.52, 8.52, and 10.52 cm, respectively, significantly higher than that of the controls. LNT prevented the development of wheat sharp eyespot. In the highly susceptible Jimai 22 cultivar, sharp eyespot development was reduced by 33.7%, 31.9%, and 30.4% at 7, 14, and 21 days after germination. LNT somewhat increased phenylalanine ammonia-lyase, peroxidase, and superoxide dismutase activity; reduced the malondialdehyde content; increased chlorophyll a and b levels; and enhanced the root vigor of wheat. These effects peaked 7 days after germination. LNT increased transcription of the genes encoding alternative oxidase (AOX) and β-1,3-glucanase (GLU), the salicylic acid signaling pathway-related gene NbPR1a, and the sharp eyespot resistance-related gene RS33. A significant dose-effect relationship was evident in terms of AOX transcription; we thus speculate that AOX may be the target gene.

Comparison of the effect of ionic liquids containing hexafluorophosphate and trifluoroacetate anions on the inhibition of growth and oxidative stress in spring barley and common radish

Ionic liquids are a group of chemical compounds with chemical properties that are of great interest to various fields of science and industry. However, commercial use of these substances raises concern because they may threaten the natural ecosystems. The present study used 2 types of (-)-menthol-containing imidazolium chiral ionic liquids: 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-methylimidazolium hexafluorophosphate [Im-Men][PF₆ ] and 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-methylimidazolium trifluoroacetate [Im-Men][CF₃ CO₂ ]. The effects of these compounds on growth and development of spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers.) were investigated. The present study demonstrated that chiral ionic liquids produced a relatively high phytotoxicity, by shortening the plants' lengths and roots, thus causing a decline in the experimental plants' fresh weights. The investigated ionic liquids also led to a reduction in photosynthetic pigment levels, changes in hydrogen peroxide and malondialdehyde content, and changes in the activities of superoxide dismutase, catalase, and peroxidase in both plants. Changes in these enzymes were used to indicate oxidative stress levels in spring barley and common radish. It was demonstrated that imidazolium ionic liquid-induced phytotoxicity depended largely on the type of anion. The liquid [Im-Men][PF₆ ] exhibited higher toxicity toward spring barley and common radish seedlings. Common radish was more resistant to chiral ionic liquids. Environ Toxicol Chem 2017;36:2167-2177. © 2017 SETAC.

Acute Toxicity of Imidazole Nitrate Ionic Liquids with Varying Chain Lengths to Earthworms (Eisenia foetida)

When ionic liquids (ILs) first came into use, we thought that they were safe. However, upon further investigation, researchers found that ILs are not harmless. In this study, the model soil organism, earthworms (Eisenia foetida), were used to study the acute toxicity of imidazole nitrate ionic liquids with varying chain lengths from 2 to 12. The experiment used two different methods, a filter paper contact test (48 h) and an artificial soil test (14 days), to determine the toxicity. These results demonstrated that the toxicity increased with the length of carbon chains until C₈ and that the cut-off effect occurred at 1-octyl-3-methyl imidazole nitrates.Then, the toxicity began to increase again. At the same time, the concentrations of [C₁₀mim]NO₃ and [C₁₂mim]NO₃ were determined by high performance liquid chromatography and demonstrated that ILs were stable throughout the experiment. The present study revealed the acute toxicity of ILs with varying chain lengths.

Role of cation structure in the phytotoxicity of ionic liquids: growth inhibition and oxidative stress in spring barley and common radish

The present study determines the influence of three ionic liquids (ILs) containing cations with diversified structure on the growth and development of spring barley seedlings and common radish leaves. Increasing amounts of 1-butyl-1-methylpyrrolidinium hexafluorophosphate [Pyrrol][PF₆], 1-butyl-1-methylpiperidinium hexafluorophosphate [Piper][PF₆], and 1-butyl-4-methylpyridinium hexafluorophosphate [Pyrid][PF₆] were added to the soil on which both plants were cultivated. The results of this studies showed that the applied ILs were highly toxic for plants, demonstrated by the inhibition of length of plant shoots and roots, decrease of fresh mass, and increase of dry weight content. Common radish turned out to be the plant with higher resistance to the used ILs. The differences in the cation structure did not influence phytotoxity of ILs for spring barley. Furthermore, all ILs led to a decrease of photosynthetic pigments, which was directly followed by decreased primary production in plants. Oxidative stress in plants occurred due to the presence of ILs in the soil, which was demonstrated by the increase of malondialdehyde (MDA) content, changes in the H₂O₂ level, and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). The changes in the chlorophyll contents and the increase of POD activity turned out to be the most significant oxidative stress biomarkers in spring barley and common radish. Both spring barley and radish exposed to ILs accumulated a large amount of fluoride ion.

Reaction of Spring Barley and Common Radish on the Introduction of Ionic Liquids Containing Asymmetric Cations to the Soil

The harmful effect of ionic liquids (ILs) on the environment is one of the important elements of scientific research conducted around the world. This study presents the effect of ionic liquids, containing the asymmetric cations benzyltrimethylammonium chloride [BenzTMA][Cl] and benzyltriethylammonium chloride [BenzTEA][Cl], on physiological and biochemical changes in common radish plants and spring barley seedlings. The examined ILs demonstrated low toxicity to higher plants. The compound that exhibited higher phytotoxicity to these plant species was [BenzTMA][Cl], whereas the plant that was more resistant to such ILs was common radish. Both the ionic liquids, particularly at higher concentrations, led to changes in the metabolism of plants, which resulted in a decrease of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids content. The observed changes were positively correlated with increasing concentrations of the examined ILs in the soil. In the case of spring barley, a decrease in the fresh weight and an increase in the dry weight of the seedlings were also observed. The evidence of oxidative stress occurrence in spring barley was observed due to the accumulation of malondialdehyde and free proline, as well as due to an increase in the activity of catalase and peroxidase. The changes in these biomarkers indicating oxidative stress occurrence in common radish plants were much lower. An increase in the content of chloride ions was observed in both the plants.

Environmental Impact of Ionic Liquids: Recent Advances in (Eco)toxicology and (Bio)degradability

This Review aims to integrate the most recent and pertinent data available on the (bio)degradability and toxicity of ionic liquids for global and critical analysis and on the conscious use of these compounds on a large scale thereafter. The integrated data will enable focus on the recognition of toxicophores and on the way the community has been dealing with them, with the aim to obtain greener and safer ionic liquids. Also, an update of the most recent biotic and abiotic methods developed to overcome some of these challenging issues will be presented. The review structure aims to present a potential sequence of events that can occur upon discharging ionic liquids into the environment and the potential long-term consequences.

Changes in growth and physiological parameters of spring barley and common radish under the influence of 1-butyl-2,3-dimethylimidazolium tetrafluoroborate

Ionic liquids (ILs) constitute a large group of chemical substances, which, thanks to their desirable properties, still attract attention of scientists and representatives of the industry. This may lead to a greater commercial use of these compounds, which will undoubtedly lead to the contamination of soils, constituting the basis of plant vegetation, with these substances. This paper presents effect of 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BMMIM][BF₄] on the growth and development of spring barley and common radish and on the physiological and biochemical changes in these plants. The used IL was characterized by relatively high toxicity for the monocotyledonous plant, which was exhibited by shortening of the plant length and their root length, decreasing the fresh weight yield. Moreover, [BMMIM][BF₄] led to the decrease in the content of all photosynthetic pigments in spring barley seedlings, reflecting the decrease in the fresh yield. Furthermore, the increase of malondialdehyde (MDA) level and changes in contents of hydrogen peroxide (H₂O₂) and the activity of antioxidant enzymes, that is, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) may suggest the occurrence of oxidative stress in spring barley. The decrease in the content of photosynthetic pigment and the increase of POD activity constitute the most reliable markers of oxidative stress and, at the same time, the signs of early aging of spring barley plants. Common radish was the plant with a very high tolerance for the used IL, which can be indicated by, that is, EC₅₀ values, determined based on inhibition of root length, plant length, and fresh weight yield.

Potential toxicity of ionic liquid ([C12mim]BF4) on the growth and biochemical characteristics of a marine diatom Phaeodactylum tricornutum

Recently, some researchers have pointed out that the threats of ionic liquids (ILs) to aquatic environment cannot be ignored. Thus, this study investigated the potential toxicity of 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C₁₂mim]BF₄) on a marine diatom Phaeodactylum tricornutum at population, biochemical and physiological levels using 96h growth tests with a batch-culture system. Results showed that [C₁₂mim]BF₄ was very stable in aquatic environment during 96h of exposure. The growth of P. tricornutum was significantly inhibited by [C₁₂mim]BF₄ with 24, 48, 72 and 96h EC₅₀ values of 0.63, 0.61, 0.68 and 0.72mgL^-1, respectively. Although there were no significant differences between the controls and treatments with 0.1 and 0.5mgL^-1 [C₁₂mim]BF₄, the effective quantum yields (Φ_PSII) of the diatom in 1, 2.5, 5 and 10mgL^-1 [C₁₂mim]BF₄ treatments were 61.48, 17.04, 2.96 and 0.74% of that in the controls at 96h of exposure, respectively. Chl a content of the diatom was decreased by 34.86, 47.79, 49.81, 59.21, 79.82 and 86.98% compared with that of the controls at 96h of exposure in 0.1, 0.5, 1, 2.5, 5 and 10mgL^-1 [C₁₂mim]BF₄ treatments, respectively. Relative to the controls, soluble sugar content, reactive oxygen species (ROS) level, malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) activities of the diatom increased with increasing [C₁₂mim]BF₄ concentrations at 96h of exposure, and reached their maxima (1.46μg10⁶cell^-1, 7.48FU10⁷cell^-1, 3.35nmol10⁸cell^-1, 33.41 and 7.23Umg^-1 proteins, respectively) in 5mgL^-1 [C₁₂mim]BF₄ treatments. While the maximum soluble protein content (1.56μg10⁶cell^-1) of the diatom was obtained in 0.5mgL^-1 [C₁₂mim]BF₄ treatments, and then decreased with increasing [C₁₂mim]BF₄ concentrations from 0.5 to 10mgL^-1. These findings provide strong evidence for the potential toxicity of ILs to marine diatoms.

Growth inhibition and efficiency of the antioxidant system in spring barley and common radish grown on soil polluted ionic liquids with iodide anions

Ionic liquids (ILs) constitute a huge group of substances that are increasingly common in the commercial use. This situation may lead to the contamination of the soil environment which being the basic of plants vegetation. This paper presents the effect of four ILs with I^- anion on the growth and development of spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers) and changes in metabolism of the plants. Seedlings of spring barley and common radish cultivated on soil with increasing ILs concentration exhibited typical phytotoxicity symptoms. A considerable reduction of shoot and root lengths, decrease of fresh weight (FW) and increase of dry weight (DW) occurred in both test plants. Ionic liquids concentration increase in soil was correlated with the decrease of concentrations of all photosynthetic pigments in the plants. The observed increase of malondialdehyde (MDA) concentration and changes in the H₂O₂ level indicated presence of oxidative stress in spring barley and common radish, which usually led to the increase of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity. The most reliable biomarker of oxidative stress was chlorophyll level and changes in POD activity.

Exogenous salicylic acid alleviates the toxicity of chlorpyrifos in wheat plants (Triticum aestivum)

The role of exogenous salicylic acid (SA) in protecting wheat plants (Triticum aestivum) from contamination by the insecticide chlorpyrifos was investigated in this study. The wheat plants were grown in soils with different concentrations (5, 10, 20, and 40mgkg^-1) of chlorpyrifos. When the third leaf emerged, the wheat leaves were sprayed with 1, 2, 4, 8, and 16mgL^-1 of SA once a day for 6 days. The results showed that wheat exposed to higher concentrations of chlorpyrifos (≥20mgkg^-1) caused declines in growth and chlorophyll content and altered the activities of a series of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). Interestingly, treatments with different concentrations of SA mitigated the stress generated by chlorpyrifos and improved the measured parameters to varying degrees. Furthermore, a reverse transcription and quantitative PCR experiment revealed that the activities of SOD and CAT can be regulated by their target gene in wheat when treated with SA. We also found that SA is able to block the accumulation of chlorpyrifos in wheat. However, the effect of SA was related to its concentration. In this study, the application of 2mgL^-1 of SA had the greatest ameliorating effect on chlorpyrifos toxicity in wheat plants.

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

The effect of the number of alkyl substituents on imidazolium ionic liquids phytotoxicity and oxidative stress in spring barley and common radish seedlings

Increasing amounts of two ILs: 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆] and 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [BMMIM][PF₆], were introduced to soil in which spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers.) seedlings were cultivated, in order to evaluate the phytotoxicity of ionic liquids with imidazolium cation with two or three alkyl substituents attached. The results of the study i.e. the inhibition of the length of plants and their roots, as well as the yield of fresh weight of plants, clearly showed that differences in the number of substituents did not affect the toxicity of these ILs. Although, radish was more resistant to the applied ionic liquids than barley. Ionic liquids led to a decrease in the content of all assimilation pigments and induced oxidative stress in the plants, as showed by an increase in malondialdehyde (MDA) content, and changes in the level of H₂O₂ and antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). The best biomarkers of oxidative stress in both plants were the changes in chlorophyll content and the increase in POD activity. Both spring barley and radish exposed to [BMIM][PF₆] and [BMMIM][PF₆] accumulated a large amount of fluoride ions, which further increased the toxicity of these compounds for both plants.

Oxidative stress in spring barley and common radish exposed to quaternary ammonium salts with hexafluorophosphate anion

Quaternary ammonium salts (QAS), including ionic liquids (ILs), constitute a huge group of substances, which due to their desirable physical and chemical properties still attracts great interest in many industrial sectors. An increased concentration of this compound in the environment may lead to the contamination of the natural environment and may pose a potential threat to all organisms, including terrestrial higher plants. The present study demonstrates the interaction of three QAS with PF6(-) anions - tetramethylammonium [TMA][PF6], tetrabutylammonium [TBA][PF6], and tetrahexylammonium [THA][PF6] hexafluorophosphates - and its impact on the physiological and biochemical changes in spring barley seedlings and common radish plants. A similar study was also carried out by introducing the inorganic salt - ammonium hexafluorophosphate [A][PF6] to the soil; the results showed the soil became highly toxic to both plants. All the salts used led to significant changes in the metabolism of both spring barley and common radish which can be evidenced, for example, by a decrease in the content of chlorophyll a (Chla), chlorophyll b (Chlb), and total chlorophyll (Chla + b), as well as carotenoids (Car). The decrease in assimilation pigments was linearly correlated with an increasing concentration of QAS in the soil. QAS and [A][PF6] led to the formation of oxidative stress in both experimental plants, as evidenced by an increase in malondialdehyde (MDA) content in their cells and the changes in H2O2 level. In response to stress, the plants synthesized enzymatic free radicals (ROS) scavengers that lead to changes in the activity of superoxide dismutase (SOD) and catalase (CAT), as well as significantly increased peroxidase (POD) activity. A decrease in the content of assimilation pigments and an increased POD activity are the most reliable indices of oxidative stress, and concurrently the signs of premature plants aging. Common radish proved to be more resistant to the presence of QAS in the soil compared to spring barley.

Comparative toxicity of nonylphenol, nonylphenol-4-ethoxylate and nonylphenol-10-ethoxylate to wheat seedlings (Triticum aestivum L.)

Nonylphenol polyethoxylates (NPEOs) are a group of surfactants that are widely used in industrial and household products and often detected in the environment. The metabolite of NPEOs, named nonylphenol (NP), has proven to be an endocrine disruptor, and its environmental behavior and eco-toxicity have been widely investigated in previous studies. However, to the best of our knowledge, insight into the toxicity differences of NP and NPEOs on important crops remains limited. Therefore, this study investigated the comparative toxicity of NP, nonylphenol-4-ethoxylate (NP4EO), and nonylphenol-10-ethoxylate (NP10EO) on wheat seedlings using hydroponic experiments. The results indicated that NP is most toxic to wheat followed by NP4EO, and NP10EO is the least toxic to wheat. The adverse effects of NP on wheat were observed for all the tested parameters including germination, shoot length, root length, chlorophyll, lipid peroxidation, and enzymatic activities. To gain insight into the molecular response, we analyzed the transcript abundance of SOD-Cu/Zn and CAT with NP, NP4EO, and NP10EO exposure using quantitative real-time PCR. The data revealed that both genes exhibited up- or down-regulated expression patterns that were consistent with the activities of the two enzymes. This result further conformed that NP is most toxic to wheat plants.

Biological responses of Vicia faba seedlings to the imidazolium-based ionic liquid 1-hexyl-3-methylimidazolium chloride in soil

Although there are a few studies on the toxicity of ionic liquids (ILs), relatively little is known about their toxic effects on plants in soil. In the present study, the toxic effects of 1-hexyl-3-methylimidazolium chloride ([Hmim]Cl) in the soil on Vicia faba seedlings and the influences of [Hmim]Cl on the physicochemical properties of the soil were studied. Organic matter content, pH, and conductivity of the tested soil were significantly altered at [Hmim]Cl concentrations greater than 1000 mg kg(-1) . Moreover, shoot length, root length, dry weight, and pigment content of the V. faba seedlings were greatly inhibited when the [Hmim]Cl concentration was greater than 500 mg kg(-1) . The roots were the most seriously affected organ and stopped growing at 3000 mg kg(-1) . In addition, [Hmim]Cl caused an increase in the level of reactive oxygen species at [Hmim]Cl concentrations above 250 mg kg(-1) that resulted in lipid peroxidation, DNA damage, and oxidative stress in the V. faba seedlings. The present study provides information that is useful for evaluation of the environmental safety of ILs in soil. Environ Toxicol Chem 2016;35:1502-1510. © 2015 SETAC.

Evaluation of the effect of tetraethylammonium bromide and chloride on the growth and development of terrestrial plants

Quaternary ammonium salts (QAS), which also include ionic liquids, constitute a vast group of chemical compounds that are increasingly common in the commercial use. This situation may lead to the contamination of the natural environment and may constitute a potential threat to all its elements, including terrestrial higher plants. This paper presents the effect of tetraethylammonium chloride [TEA][Cl] and tetraethylammonium bromide [TEA][Br] on the growth and development of spring barley and common radish. The applied QAS were characterized with phytotoxicity dependent on the concentration of compound and characteristics of the study plants. Spring barley turned out to be highly susceptible plant to the analyzed compounds, which was confirmed by % inhibition of length of plants, root length and fresh weight of plants and by calculated values for EC50, NOEC as well as LOEC. On the contrary, a common radish revealed the resistance to QAS used in the study; although, phytotoxic symptoms were still observed when high concentrations of dry weight of soil were applied (1000, 3000 and 5000 mg/kg). The applied QAS caused oxidative stress symptoms, mainly in spring barley seedlings, which were manifested by decreased assimilation of pigments content, increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) content in plant cells and with a changed activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD).

Biochemical responses and DNA damage in earthworms (Eisenia fetida) induced by ionic liquid [omim]PF6

Ionic liquids that are not that "green" to many organisms have recently been identified. This study examined the subchronic toxicity of the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate ([omim]PF6) to earthworms (Eisenia fetida). Earthworms were exposed for a 28-day period (sampled on days 7, 14, 21, and 28) at concentrations of 0, 5, 10, 20, and 40 mg/kg. The levels of reactive oxygen species (ROS), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD)), detoxifying enzyme (glutathione S-transferase (GST)), lipid peroxidation, and DNA damage were measured. ROS significantly accumulated in all the treatment groups; the maximum ROS content was 51.9% higher than the control at 40 mg/kg [omim]PF6 on day 28. Increased SOD activities attenuated over the time of exposure, while the CAT activities of the treatment groups were similar to the controls, except on day 14. Furthermore, the activities of POD and GST were stimulated. Lipid peroxidation in earthworms was not apparent at 5 and 10 mg/kg [omim]PF6 but was quite obvious at 40 mg/kg [omim]PF6. In addition, DNA damage was dose- and time-dependent. In conclusion, [omim]PF6 caused oxidative stress and genotoxicity in earthworms.

Growth and Physiological and Biochemical Responses of Wheat Seedlings to Imidazolium-Based Ionic Liquids 1-Octyl-3-Methylimidazolium Chloride and 1-Octyl-3-Methylimidazolium Bromide

The toxic effects of 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) and 1-octyl-3-methylimidazolium bromide ([C8mim]Br) on wheat seedlings at 0, 1, 2, 4, 6, and 8 mg L(-1) were studied on the 7th, 10th and 13th days of cultivation. In addition, the concentrations of [C8mim]Cl and [C8mim]Br in nutrient solutions were determined by high performance liquid chromatography for the first time. The results showed that the concentrations of [C8mim]Cl and [C8mim]Br in nutrient solutions were stable during the exposure period. However, the reactive oxygen species levels in the wheat seedling cells were enhanced after exposure to [C8mim]Cl and [C8mim]Br, which resulted in oxidative damage and lipid peroxidation. Additionally, the particular halide anion present in the IL compounds appeared to have little influence on the toxicity of ILs.