In vitro evaluation of novel titania-containing borate bioactive glass scaffolds.

Titanium-containing borate bioactive glass scaffolds (0, 5, 15, and 20 mol %, identified as BRT0, BRT1, BRT3, and BRT4) with a microstructure similar to that of human trabecular bone were prepared and evaluated in vitro for potential bone loss applications in revision total knee arthroplasty (rTKA). Methyl thiazolyl tetrazolium (MTT) cell viability assays of scaffold ion release extracts revealed that BRT0 scaffolds (0 mol % titanium) inhibited cell proliferation and activity at day 14. At day 30, all scaffold extracts decreased cell proliferation and activity significantly. However, live/dead cell assay results demonstrated that degradation products from all the scaffolds had no inhibitory effect on cell viability. Significant bactericidal efficacies of BRT3 extracts against Escherishia coli (Gram-negative) and BRT1 extracts against Staphylococcus aureus and Staphylococcus epidermidis (both Gram-positive bacteria) were demonstrated. Finally, evaluation of the cell/bioactive glass surface interactions showed well-spread cells on the surface of the BRT3 glass discs and BRT1 and BRT3 scaffolds, when compared to BRT0 and BRT4 scaffolds. The results indicate that by changing the Ti4+ :B3+ ratio, the ion release and consequently cell proliferation could be improved. in vitro results in this study demonstrate that BRT3 scaffolds could be a promising candidate for addressing bone loss in rTKAs; however, in vivo studies would be required to evaluate the effect of a dynamic environment on the cell and tissue response to the fabricated scaffolds.

The effects of 1-hexyl-3-methylimidazolium bromide on embryonic development and reproduction in Daphnia magna.

Ionic liquids (ILs) are acknowledged as green chemicals and favorable substitutes for volatile organic solvents, which are currently used. However, previous studies have shown that these compounds had toxicological impacts on aquatic organisms. To investigate the effects of 1-hexyl-3- methylimidazolium bromide ionic liquid ([C6mim]Br) on embryonic development and reproduction in water flea (Daphnia magna), a series of exposure experiments were conducted, including acute toxicity, maternal exposure, and chronic exposure tests. In acute toxicity experiment, D. magna neonates exhibited developmental abnormalities in the shell spine and the second antennae in a concentration-dependent manner after exposure to [C6mim]Br. The results in maternal exposure test also revealed a certain embryo-toxicity in response to [C6mim]Br in D. magna. However, the toxicity was lower than that conveyed by direct acute exposure, this indicated that the IL could act directly on organism. During the 21 days chronic exposure, the 1.6 mg/L exposure caused marked drop in the survival, molts and the number of the first brood of D. magna. Meanwhile, the total number of offspring was significantly declined in 1.6 mg/L concentration treatment groups, whereas increased in 0.2 mg/L groups. Generally, abnormalities in the offspring were significantly increased across all of the treatment groups in contrast to the control. No effect on sex differentiation was found during the experiments. These findings suggested that [C6mim]Br could affect embryonic development and reproduction in D. magna, and provided references for further study on the mechanisms underlying toxicological effects of ILs and the assessment of their potential environmental risks.

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]BF4.

Integrative Assessment of Mixture Toxicity of Three Ionic Liquids on Acetylcholinesterase Using a Progressive Approach from 1D Point, 2D Curve, to 3D Surface.

The joint toxicities of [BMIM]BF4, [BMIM]PF6, and [HMIM]BF4 on acetylcholinesterase (AChE) were systematically investigated by using a progressive approach from 1D single effect point, 2D concentration-response curve (CRC), to 3D equivalent-surface (ES) level. The equipartition equivalent-surface design (EESD) method was used to design 10 ternary mixtures, and the direct equipartition ray (EquRay) design was used to design 15 binary mixtures. The toxicities of ionic liquids (ILs) and their mixtures were determined using the microplate toxicity analysis (MTA) method. The concentration addition (CA), independent action (IA), and co-toxicity coefficient (CTC) were used as the additive reference model to analyze the toxic interaction of these mixtures. The results showed that the Weibull function fitted well the CRCs of the three ILs and their mixtures with the coefficient of determination (R2) greater than 0.99 and root-mean-square error (RMSE) less than 0.04. According to the CTC integrated with confidence interval (CI) method (CTCICI) developed in this study, the 25 mixtures were almost all additive action at 20% and 80% effect point levels. At 50% effect, at least half of the 25 mixtures were slightly synergistic action, and the remaining mixtures were additive action. Furthermore, the ESs and CRCs predicted by CA and IA were all within the CIs of mixture observed ESs and CRCs, respectively. Therefore, the toxic interactions of these 25 mixtures were actually additive action. The joint toxicity of the three ILs can be effectively evaluated by the ES method. We also studied the relationship between the mixture toxicities and component concentration proportions. This study can provide reference data for IL risk assessment of combined pollution.

Toxicity comparison of three imidazolium bromide ionic liquids to soil microorganisms.

Ionic liquids (ILs) are extensively used in several chemistry fields. And research about the effects of ILs on soil microbes is needed. In this study, brown soil was exposed to 1-butyl-3-methylimidazolium bromide ([C4mim]Br), 1-hexyl-3-methylimidazolium bromide ([C6mim]Br) and 1-decyl-3-methylimidazolium bromide ([C10mim]Br). The toxicities of the three ILs are evaluated by measuring the soil culturable microbial number, enzyme activity, microbial diversity and, abundance of the ammonia monooxygenase (amoA) genes of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Results showed that all tested ILs caused a decrease in culturable microbial abundance. Tested ILs exposure inhibit urease activity and promote acid phosphatase and ß-glucosidase activities. Tested ILs reduced soil microbial diversity and the abundances of AOB-amoA and AOA-amoA genes significantly. After a comparison of the integrated biomarker response (IBR) index, the toxicities of tested ILs to soil microorganisms were as follows: [C10mim]Br > [C6mim]Br > [C4mim]Br. Among all collected biomarkers, the abundance of the AOA-amoA gene was the most sensitive one and was easily affected after ILs exposure.

Responses of Chlorella vulgaris exposed to boron: Mechanisms of toxicity assessed by multiple endpoints.

Boron (B) has been widely used and contaminated the aquatic ecosystem. However, knowledge of the effects of sodium pentaborate pentahydrate (SPP) on algae remains limited. This study aimed to assess SPP toxicity using multiple endpoints, specially detecting the intracellular metal ion concentrations, malondialdehyde (MDA) content and extracellular polymeric substance (EPS) classes for the very first time during SPP exposure to Chlorella vulgaris (C. vulgaris). Our findings indicated that the inhibitory effects of SPP on C. vulgaris may be related to nutrient absorption and utilization. The changes in intracellular starch grains, MDA and the protein-like substances in EPS probably acted as a defense mechanism, helping to alleviate the toxic effects. This work may contribute to the understanding of the mechanism of SPP toxicity in algae. Further studies may focus on the effects of B on speciation of metallic ions and the interaction of B with metallic ions on aquatic organisms.

Cytotoxic potential of denture base and reline acrylic resins after immersion in disinfectant solutions.

STATEMENT OF PROBLEM: The daily immersion of dentures in disinfectant solutions can cause the incorporation of toxic substances in the acrylic resins, and studies evaluating the cumulative effect of disinfectant solutions on cell culture are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the cytotoxic potential of cell cultures of denture base and reline acrylic resins after immersion in disinfectant solutions. MATERIAL AND METHODS: Disk-shaped specimens (14×1.2 mm) were obtained and divided into groups (n=9) according to the disinfectant solutions (distilled water [control], 2% chlorhexidine digluconate, 3.8% sodium perborate, 0.5% sodium hypochlorite, and apple vinegar) and to the storage period (0, 1, 3, and 6 months). Solutions were changed daily. After the different storage periods, specimens were immersed in culture medium for 24 hours, and extracts were obtained. Human keratinocytes were cultivated, and the cellular metabolism was evaluated by using Alamar Blue. Data were submitted to 3-way analysis of variance and Games-Howell post hoc tests (α=.05). RESULTS: Both of the acrylic resins tested showed similar biocompatibility properties after immersion in different solutions (P=.400). Immersion in distilled water, 3.8% sodium perborate, and 0.5% sodium hypochlorite did not affect the cellular metabolism of the keratinocytes (P>.05), regardless of the immersion period and the type of acrylic resin (P>.05). Immersion in 2% chlorhexidine digluconate or apple vinegar resulted in high cytotoxicity over time, until the third month (P<.05), after which no changes were observed (P>.05). CONCLUSIONS: The type of acrylic resin (base or reline) had no significant effect on the viability of cells. Vinegar and chlorhexidine digluconate solutions increased in cytotoxic effect over time, and were strongly cytotoxic after 6 months of immersion. Sodium perborate and sodium hypochlorite were noncytotoxic in all periods of time tested.

N-hydroxymethylglycinate with EDTA is an efficient eye drop preservative with very low toxicity: an in vitro comparative study.

PURPOSE: Preservatives are used in multi-dose ophthalmic topical medications in order to prevent contamination by bacteria and fungi. However, prolonged use of preserved eye drops, as it may happen in dry eye or glaucoma, may damage cells of the ocular surface. Therefore, an important goal is to find preservatives with low toxicity which are mild to host cells, still able to prevent drug contamination so to maintain their sterility and efficacy. Hence, aim of this study has been to compare the relative toxicity on a rabbit corneal cell line of a new preservative, made by the association of N-hydroxy-methyl-glycinate (NIG) with disodium-ethylene diamine tetra-acetate (EDTA), with other known and widely used eye-drops preservatives. MATERIALS AND METHODS: Rabbit corneal cells (SIRC) were tested either in 96-well plates or in suspension culture. Treatments with preservatives (used at known bacteriostatic concentrations) included: benzalkonium chloride (BAK), polyquaternium-1 (PQ-1), sodium perborate (SP: NaBO3 * H2O), and NIG ± EDTA at different concentrations (0.001% and 0.002%), and different treatment times (from 30 minutes to 120 hours). At the end of treatment, cell survival was evaluated by a specific spectrophotometric method through the metabolic conversion of MTT [3-(4,5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide] into formazan crystals. RESULTS: Almost no cell toxicity was evident for NIG and SP at either concentration (0.001% or 0.002%), while a low toxicity was observed for PQ-1 (62% at the highest dose at 120 hours). BAK, as expected, showed the highest toxicity (60-80% at 30 minutes, and over 90% from eight hours onward). EDTA 0.1% alone or in combination with NIG 0.002%, showed no toxicity at 24 hours, and even resulted in cell growth promotion (46% and 38%, respectively), after 48 hours of treatment. CONCLUSIONS: These data show that the new preservative NIG/EDTA, at doses known to have effective antimicrobial properties, has a very low toxicity on corneal cells, and so it can be safely used in multi-dose eye drops.

Antimicrobial agents, triclosan, chloroxylenol, methylisothiazolinone and borax, used in cleaning had genotoxic and histopathologic effects on rainbow trout.

Triclosan (TRC), chloroxylenol (PCMX) and methylisothiazolinone (MIT) have been commonly used as an antimicrobial in soaps while borax (BRX) is used in household cleaning. After using these chemicals, they are washed down drains and getting into the aquatic ecosystem in which they may affect aquatic living organisms. In the present study, the chronic effects of TRC, PCMX, MIT and BRX on genotoxicity, gene expression and histopathology of rainbow trout (Oncorhynchus mykiss) were evaluated for 40 days under semi static condition. The comet assay results indicated that MIT, TRC and PCMX caused significant DNA damage to erythrocytes of the fish. Transcription of SOD, GPX1, GPX2, GSTA, HSP90BB, HSP90BA, CAT, and HSC70A genes were significantly regulated as a result of TRC, PCMX, MIT, and BRX exposure except PCMX exposed GSTA gene. Histological lesions were detected in gills, spleen liver, and trunk kidney of the fish. Lamellar fusion, hyperplasia and epithelial necrosis in gills, melanomacrophage centers and splenic necrosis in spleen, pyknotic nucleus, fat vacuoles, necrotic hepatocytes in liver, cloudy swelling in the tubules, renal tubule epithelial cells degeneration, glomerular capillaries dilation and glomerulus degeneration in kidney, were observed. Our study demonstrates the chronic toxic effect of TRC, PCMX, MIT, and BRX is high in rainbow trout. Therefore, we should be more careful when using these chemicals for cleaning in order to protect aquatic environment.

The acute toxic effects of imidazolium-based ionic liquids with different alkyl-chain lengths and anions on zebrafish (Danio rerio).

With the increasing applications of ionic liquids (ILs), the toxicity of ILs has drawn increasing attention in recent years, especially the influences of different anions and alkyl-chain lengths on the acute toxicity to aquatic organisms. We performed a study on the acute toxicity of 1-alkyl-3-methylimidazolium nitrate ([Cnmim]NO3 (n=2, 4, 6, 8, 10, 12)), 1-hexyl-3-methylimidazolium ILs ([C6mim]R (R=Cl-, Br-, BF4-, PF6-)) to zebrafish (Danio rerio). We also evaluated the sensibility of the investigated animals and the stability of ILs in water via high performance liquid chromatography (HPLC, Agilent 1260, Agilent Technologies Inc., USA) to prove the reliability of the present study. The results illustrated that the test zebrafish (Danio rerio) were sensitive to the reference toxicant and that the investigated ILs in water were stable. The 50% lethal concentration (LC50) was used to represent the acute toxicity to zebrafish (Danio rerio). The present study showed that the highest toxic IL is [C12mim]NO3 and the lowest toxic IL is [C2mim]NO3 on Danio rerio. The LC50s for ILs with different anions had similar values. Accordingly, we believe that ILs with different alkyl-chain lengths cause greater effects than other anions on acute toxicity to aquatic organisms. Furthermore, the present study can also provide scientific methods for future studies to select and assess ILs.

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 (ΦPSII) 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.

Sodium perbarate and benzalkonium chloride induce DNA damage in Chang conjunctival epithelial cells.

Content and objective: To investigate and compare the toxic effects of benzalkonium chloride (BAC) and new type oxidative preservative sodium perborate (NaBO3) on DNA damage, reactive oxygen species (ROS), and cell survival in immortalized human Chang conjunctival cells. MATERIALS AND METHODS: Cells were exposed to BAC and NaBO3 in concentrations of 0.00001-0.001% for 30 min. Cell viability was measured by the MTT test. Alkaline comet assay was used to detect DNA damage. Mitochondrial membrane potential (MMP), cell apoptosis, and ROS production were detected by flow cytometry analysis. RESULTS: Significant changes in the relative cell survival rate in cells were observed after exposure to 0.0005-0.001% BAC for 30 min (p < 0.001). DNA damage and intracellular ROS were observed in a dose-dependent manner with BAC exposure (p < 0.001). However, 0.001% BAC induced less ROS than 0.0005% BAC. A decrease in MMP was also recorded. NaBO3 did not induce the decrease in cell survival and MMP in low concentration but could induce DNA damage and ROS generation in a 0.001% concentration (p < 0.001). DISCUSSION AND CONCLUSIONS: BAC can induce DNA damage in human conjunctival epithelial cells; this effect may be related to oxidative stress. Although NaBO3 did not induce a significant decrease in cell survival and MMP, DNA damage and ROS generation were still detected in high concentration. New type oxidative preservative has less toxicity than the old type, but it still has the tendency of producing genotoxic changes in an in vitro test system.

Effects of sodium pentaborate pentahydrate exposure on Chlorella vulgaris growth, chlorophyll content, and enzyme activities.

Sodium pentaborate pentahydrate (SPP) is a rare mineral. In this study, SPP was synthesized from boric acid and borax through low-temperature crystallization, and its effects on the growth of the alga, Chlorella vulgaris (C. vulgaris) were assessed. The newly synthesized SPP was characterized by chemical analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and differential thermal analysis. The changes in C. vulgaris growth, chlorophyll content, and enzyme activities upon exposure to SPP for 168h were evaluated. Results showed that SPP treatment was detrimental to C. vulgaris growth during the first 24-120h of exposure. The harmful effects, however, diminished over time (168h), even at an effective medium concentration of 226.37mg BL(-1) (the concentration of boron applied per liter of culture medium). A similar trend was observed for chlorophyll content (chlorophyll a and b) and indicated that the photosynthesis of C. vulgaris was not affected and that high levels of SPP may even promote chlorophyll synthesis. Superoxide dismutase and catalase activities of C. vulgaris increased during 24-120h exposure to SPP, but these activities gradually decreased as culture time progressed. In other words, the initial detrimental effects of synthetic SPP on C. vulgaris were temporary and reversible. This research provides a scientific basis for applications of SPP in the environment.

Borax-induced apoptosis in HepG2 cells involves p53, Bcl-2, and Bax.

Borax, a boron compound and a salt of boric acid, is known to inhibit the growth of tumor cells. HepG2 cells have been shown to be clearly susceptible to the anti-proliferative effects of borax. However, the specific mechanisms regulating this effect are poorly understood. This study aimed to investigate the pathways underlying the growth inhibition induced by borax in HepG2 cells. The effects of borax on HepG2 cell viability were characterized using MTT. Apoptosis was also verified by annexin V/propidium iodide staining. JC-1 dye and western blotting techniques were used to measure mitochondrial membrane potential and p53, Bax, and Bcl-2 protein expression, respectively. Relevant mRNA levels were measured by qRT-PCR. Borax inhibited the proliferation of HepG2 cells in a time- and dose-dependent manner in vitro. The apoptotic process triggered by borax involved the upregulation of p53 and Bax and the downregulation of Bcl-2, which was confirmed by a change in the mitochondrial membrane potential. These results elucidate a borax-induced apoptotic pathway in HepG2 cells that involves the upregulation of p53 and Bax and the downregulation of Bcl-2.

[STRUCTURE OF THE SPLEEN AT CHRONIC INTOXICATION OF THE ORGANISM BY SODIUM TETRABORATE AND AFTER INTOXICATION].

The structure of a spleen of 110 white not purebred rats - males (10 intact, 50 control, 50 experimental) at chronic intoxication by sodium tetraborate and the after intoxication period - the 7, 14, 30 and 60 days were studied. Chronic impact of sodium tetraborate on an organism resulted into increase in the relative weight of a spleen in comparison with body weight that led to increase in weight coefficient of a spleen. Increase in the relative area of all functional zones (periarterial zone, the germinal center, mantle and marginal zones) of lymphoid slug of a white pulp is established. Decrease of an index a red/white pulp, as a result of increase of the area of a white pulp in response to chronic intoxication of an organism is revealed. During the after intoxication period as a result of decrease in immune tension there occured decrease of body weight and decrease in the area of a white pulp. During this period there was a reliable decrease of the area of lymphoid slug and decrease in the area of its functional zones (a periarterial zone, the center of manifolding, mantle and marginal zones).

Subchronic and genetic safety evaluation of a calcium fructoborate in rats.

A branded calcium fructoborate product, a nature-identical calcium salt of bis (fructose) ester of boric acid found in plants and a natural source of boron in the human diet and sold under the trade name FruiteX-B(®) Brand Calcium Fructoborate ("FrxB"), was evaluated in a 90-day dietary toxicity study and two genotoxicity studies. In the 90-day study, four groups of 10 male and 10 female Crl:SD CD(®) IGS rats were fed diets with FrxB admixtures of 0.56, 1.12, and 1.68% dietary concentration, providing mean overall daily intakes of FrxB in male rats of 385.8, 774.9, and 1161.3 mg/kg bw/day, and 392.1, 784.4, and 1171.1 mg/kg bw/day in female rats. There were no mortalities, no clinical or ophthalmologic signs, body weight, body weight gain, food consumption, food efficiency, Functional Observational Battery (FOB), or Motor Activity (MA) findings associated with the administration of FrxB. There were no adverse changes in hematology, coagulation, clinical chemistry, or urinalysis parameters in male or female rats considered the result of test substance administration. At necropsy, there were no macroscopic, histopathological findings, or organ weight changes deemed related to administration of the test substance. Under the conditions of this study, based on the toxicological endpoints evaluated, the no-observed-adverse-effect level (NOAEL) for FrxB in the diet was 1161.3 and 1171.1 mg/kg bw/day in male and female rats, respectively. Bacterial mutagenicity studies and a micronucleus test using Chinese hamster V79 cells demonstrated no mutagenic or genotoxic potential of the tested brand of calcium fructoborate.

Effects of the ionic liquid 1-hexyl-3-methylimidazolium bromide on root gravitropism in Arabidopsis seedlings.

The toxic effects of ionic liquids (ILs) have attracted increasing attention in recent years. However, the knowledge about the toxic effects of ILs on tropism in organisms remains quite limited. In this study, the effects of 1-hexyl-3-methylimidazolium bromide [C6mim]Br on root gravitropism were evaluated using Arabidopsis seedlings. Our results showed that the root growth and gravity response were significantly inhibited with increasing IL concentration. [C6mim]Br treatment affected the amount and distribution pattern of amyloplasts in root cap compared with controls. The auxin distribution marked with DR5rev::VENUS was altered in IL-treated seedlings. The signal intensity and gene expression of auxin efflux carriers PIN2 and PIN3 were obviously decreased by IL stress. Moreover, as consequences in response to gravity stimulus, the asymmetric DR5 signals in control root apex were impaired by IL treatment. The predominant PIN2 signals along the lower flank of root and PIN3 polarization in columella cells were also significantly reduced in seedlings exposed to IL. Our results suggest that the ionic liquid [C6mim]Br affects the amount and distribution of amyloplasts and disturbs the deployment of PIN2 and PIN3, thus impairing auxin flows in response to gravity stimulus and causing deficient root gravitropism in Arabidopsis seedlings.

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.

Effect of 1-octyl-3-methylimidazolium chloride on cell replication and membrane permeability of Escherichia coli DH5α.

Ionic liquids (ILs) have elicited attention due to their unique properties. ILs may pose environmental risks to aquatic ecosystems once released into water during generation and application. Therefore, the toxic and antimicrobial properties of ILs should be analysed. This study aims to evaluate the cytotoxicity of 1-octyl-3-methylimidazolium chloride ([C8mim] [Cl]) on Escherichia coli DH5α by MTT (3-[4,5-dimethylthiazol-2yl]-2,5 diphenyl tetrazolium bromide) assay, and to determine the effect of [C8mim] [Cl] on the replication and membrane permeability of E. coli DH5α. The results showed that [C8mim] [Cl] decreased cell viability and inhibited bacterial cell replication. [C8mim] [Cl] increased protein and nucleic acid contents in the extracellular fluid, damaged the cell membrane, and increased membrane permeability. The increase of cell membrane permeability induced by [C8mim] [Cl] could be the cause of decreased cell viability and replication.

Derivation of an occupational exposure limit for inorganic borates using a weight of evidence approach.

Inorganic borates are encountered in many settings worldwide, spurring international efforts to develop exposure guidance (US EPA, 2004; WHO, 2009; ATSDR, 2010) and occupational exposure limits (OEL) (ACGIH, 2005; MAK, 2011). We derived an updated OEL to reflect new data and current international risk assessment frameworks. We assessed toxicity and epidemiology data on inorganic borates to identify relevant adverse effects. International risk assessment frameworks (IPCS, 2005, 2007) were used to evaluate endpoint candidates: reproductive toxicity, developmental toxicity, and sensory irritation. For each endpoint, a preliminary OEL was derived and adjusted based on consideration of toxicokinetics, toxicodynamics, and other uncertainties. Selection of the endpoint point of departures (PODs) is supported by dose-response modeling. Developmental toxicity was the most sensitive systemic effect. An OEL of 1.6mgB/m(3) was estimated for this effect based on a POD of 63mgB/m(3) with an uncertainty factor (UF) of 40. Sensory irritation was considered to be the most sensitive effect for the portal of entry. An OEL of 1.4mgB/m(3) was estimated for this effect based on the identified POD and an UF of 1. An OEL of 1.4mgB/m(3) as an 8-h time-weighted average (TWA) is recommended.