微生物燃料电池型生物毒性传感器对5种典型农药的毒性检测

目前,微生物燃料电池(microbialfuelcell,MFC)型生物毒性传感器被广泛用于检测重金属、氰化物和抗生素等污染物,但将其应用于检测农药的研究极少.为此,探究了MFC型生物毒性传感器对溴氰菊酯、敌百虫、百菌清、莠去津和烟嘧磺隆5种典型农药的检测性能.实验结果表明:这5种典型农药的响应(产电抑制率)均与其浓度...     

Long-term disruption of growth,reproduction, and behavior after embryonic exposure of zebrafish to PAH-spiked sediment

A natural sediment spiked with three individual polycyclic aromatic hydrocarbons (PAHs; pyrene, phenanthrene and benzo[a]pyrene) was used to expose zebrafish embryos and larvae during 4 days. The total PAH concentration was 4.4 μg g^?1 which is in the range found in sediment from contaminated areas. Quantification of metabolites in the larvae after exposure confirmed the actual contamination of the larvae and indicated an active metabolism especially for pyrene and benzo[a]pyrene. After a transfer in a clean medium, the larvae were reared to adulthood and evaluated for survival, growth, reproduction, and behavior. Measured endpoints revealed a late disruption of growth (appearing at 5 months) and a trend toward a lower reproductive ability. Adults of embryos exposed to sediment spiked with PAHs displayed lethargic and/or anxiety-like behaviors. This latter behavior was also identified in offspring at larval stage. All together, these effects could have detrimental consequences on fish performances and contribution to recruitment.     

Waterborne and sediment toxicity of fluoxetine to select organisms

Ecological risk assessments of pharmaceuticals are currently difficult because little-to-no aquatic hazard and exposure information exists in the peer-reviewed literature for most therapeutics. Recently several studies have identified fluoxetine, a widely prescribed antidepressant, in municipal effluents. To evaluate the potential aquatic toxicity of fluoxetine, single species laboratory toxicity tests were performed to assess hazard to aquatic biota. Average LC(50) values for Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas were 0.756 (234 microg/l), 2.65 (820 microg/l), and 2.28 microM (705 microg/l), respectively. Pseudokirchneriella subcapitata growth and C. dubia fecundity were decreased by 0.044 (14 microg/l) and 0.72 microM (223 microg/l) fluoxetine treatments, respectively. Oryias latipes survival was not affected by fluoxteine exposure up to a concentration of 28.9 microM (8.9 mg/l). An LC(50) of 15.2 mg/kg was estimated for Chironomus tentans. Hyalella azteca survival was not affected up to 43 mg/kg fluoxetine sediment exposure. Growth lowest observed effect concentrations for C. tentans and H. azteca were 1.3 and 5.6 mg/kg, respectively. Our findings indicate that lowest measured fluoxetine effect levels are an order of magnitude higher than highest reported municipal effluent concentrations.     

Effects of the antidepressant mianserin in zebrafish: molecular markers of endocrine disruption

Due to their environmental occurrence and intrinsic biological activity, human pharmaceuticals have received increasing attention from environmental and health agencies. Of particular, ecotoxicological concern are drugs that affect nervous- and endocrine-systems. Zebrafish genome-wide oligo arrays are used to collect mechanistic information on mianserin-induced changes in gene expression in zebrafish. Gene expression analysis in brain and gonad tissue clearly demonstrated the estrogenic activity of mianserin and its potency to disrupt normal endocrine (estrogenic) signaling, based on induction of molecular biomarkers of estrogenicity (e.g., vitellogenin1 and zona pellucida proteins). The possible mechanism underlying this estrogenic activity of mianserin is disturbance of the Hypothalamo-Pituitary-Gonadal (HPG) axis by direct interference of mianserin with the serotonergic and adrenergic systems in the brain of zebrafish. Taking into account the importance of the HPG-axis, and considering the concept of 'critical window of exposure', our results reveal the importance for more elaborate testing of endocrine disruptive effects of aquatic antidepressants at different lifestages and during longer exposure periods (e.g., life cycle studies). Although there is a low concordance between the gene expression results in this study and previous cDNA microarray hybridizations, the global mechanistic expression patterns are similar in both platforms. This argues in favor of pathway-driven analysis of gene expression results compared to gene-per-gene analysis.     

Developmental toxicity of cypermethrin in embryo-larval stages of zebrafish

Cypermethrin, a type II pyrethroid insecticide, is widely used throughout the world in agriculture, forestry, horticulture and homes. Though the neurotoxicity of cypermethrin has been thoroughly studied in adult rodents, little is so far available regarding the developmental toxicity of cypermethrin to fish in early life stages. To explore the potential developmental toxicity of cypermethrin, 4-h post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of cypermethrin (0, 25, 50, 100, 200 and 400 μg L⁻¹) until 96 h. Among a suite of morphological abnormalities, the unique phenotype curvature was observed at concentrations as low as 25 μg L⁻¹. Studies revealed that 400 μg L⁻¹ cypermethrin significantly increased malondialdehyde production. In addition, activity of antioxidative enzymes including superoxide dismutase and catalase were significantly induced in zebrafish larvae in a concentration-dependent manner. To further investigate the toxic effects of cypermethrin on fish, acridine orange (AO) staining was performed at 400 μg L⁻¹ cypermethrin and the result showed notable signs of apoptosis mainly in the nervous system. Cypermethrin also down-regulated ogg1 and increased p53 gene expression as well as the caspase-3 activity. Our results demonstrate that cypermethrin was able to induce oxidative stress and produce apoptosis through the involvement of caspases in zebrafish embryos. In this study, we investigated the developmental toxicity of cypermethrin using zebrafish embryos, which could be helpful in fully understanding the potential mechanisms of cypermethrin exposure during embryogenesis and also suggested that zebrafish could serve as an ideal model for studying developmental toxicity of environmental contaminants.     

Effects of perfluorinated compounds on development of zebrafish embryos

Perfluorinated compounds (PFCs) have been widely used in industrial and consumer products and frequently detected in many environmental media. Potential reproductive effects of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) have been reported in mice, rats and water birds. PFOS and PFOA were also confirmed developing toxicants towards zebrafish embryos; however, the reported effect concentrations were contradictory. Polyfluorinated alkylated phosphate ester surfactants (including FC807) are precursor of PFOS and PFOA; however, there is no published information about the effects of FC807 and PFNA on zebrafish embryos. Therefore, this study was conducted to determine the effects of these four PFCs on zebrafish embryos. Normal fertilized zebrafish embryos were selected to be exposed to several concentrations of PFOA, PFNA, PFOS or FC807 in 24-well cell culture plates. A digital camera was used to image morphological anomalies of embryos with a stereomicroscope. Embryos were observed through matching up to 96-h post-fertilization (hpf) and rates of survival and abnormalities recorded. PFCs caused lethality in a concentration-dependent manner with potential toxicity in the order of PFOS > FC807 > PFNA > PFOA based on 72-h LC(50). Forty-eight-hour post-fertilization pericardial edema and 72- or 96-hpf spine crooked malformation were all observed. PFOA, PFNA, PFOS and FC807 all caused structural abnormalities using early stages of development of zebrafish. The PFCs all retarded the development of zebrafish embryos. The toxicity of the PFCs was related to the length of the PFC chain and functional groups.     

Effects of phytosterols on zebrafish reproduction in multigeneration test

Zebrafish from mixed sex populations were exposed continuously across three generations to two phytosterol preparations both containing -sitosterol. The phytosterols were isolated from wood and soy beans. Blood vitellogenin levels and sex ratio changes were used as intermediate indicators of the reproduction failures. Both sterol preparations caused vitellogenin induction in the exposed fish. The wood sterol changed the sex ratio of the exposed fish. In generation F1, the predominant sex was male, and in generation F2 it was female. The soy sterol in the used test concentration was lethal to the exposed fish in generation F1. This multigeneration test evidenced that phytosterols containing -sitosterol disrupt the reproduction system of zebrafish by changing the sex ratios and by inducing the vitellogenin production in the exposed fish.     

Effects of triclosan on zebrafish early-life stages and adults

Background, aim and scope  

The biocide triclosan (TCS) is commonly used in personal care, acrylic, plastic, and textiles products. TCS has been detected in surface water in several countries, and its ecological impact is largely unknown. In this work, the toxicity of TCS in zebrafish (Danio rerio), embryos and adults was studied. Several lethal and sub-lethal endpoints were analysed in organisms exposed to TCS such as mortality, embryo development and behaviour, hatching, micronuclei and biochemical markers (cholinesterase (ChE), glutathione S-transferase (GST) and lactate dehydrogenase (LDH)).     

Acute and sub-chronic toxicity of four cytostatic drugs in zebrafish

The acute and sub-chronic effects of four cytostatic drugs—5-fluorouracil (5-FU), cisplatin (CisPt), etoposide (ET) and imatinib mesylate (IM)—on zebrafish (Danio rerio) were investigated. Acute tests were carried out in a static system in accordance with the OECD guideline 203 for adult fish and the draft guideline for fish embryos (FET test) in order to find the LC50 values of the four cytostatic drugs. Early-life stage toxicity test on zebrafish was conducted according the OECD guideline 210 using the cytostatic drugs 5-FU and IM in a semistatic system with the objective of investigating the sub-chronic effects of the cytostatic drugs on fish. In adult fish, the cytostatic drugs 5-FU and ET did not pass the limit test, thus, are considered non-toxic. In case of cisplatin, LC50 was calculated at 64.5 mg L^?1, whereas in case of IM, LC50 was at 70.8 mg L^?1. In the FET test, LC50 of 5-FU at 72-h post fertilization (hpf) was 2441.6 mg L^?1. In case of CisPt, LC50 was 349.9 mg L^?1 at 48 hpf and it progressively decreased to 81.3 mg L^?1 at 120 hpf. In addition, CisPt caused a significant delay in the hatch of larvae. In case of ET, LC50 values were not calculable as they were higher than 300 mg L^?1 at which concentration the substance crystallized in the solution. LC50 values of IM were 48 hpf; 158.3 mg L^?1 , 72 hpf; 141.6 mg L^?1, 96 hpf; 118.0 mg L^?1, and 120 hpf; 65.9 mg L^?1. In the Early-life Stage Test with 5-FU, embryonic deformities were not detected during the tests. Regarding mortalities, the 10 mg L^?1 concentration can be considered as LOEC, as statistically significant difference in mortalities was detected in this group alone. Concerning dry body weight and standard length, 1 mg L^?1 is the LOEC. In case of IM, the highest tested concentration (10 mg L^?1) can be considered LOEC for mortalities, however, the treatment did not have an effect on the other investigated parameters (dry and wet weight, standard length). All four cytostatic drugs were characterized by low toxicity in zebrafish in acute and sub-chronic tests.     

Acute toxicity of 353-nonylphenol and its metabolites for zebrafish embryos

Background, aim and scope  Nonylphenol (NP) can be detected in the aquatic environment all over the world. It is applied as a technical mixture of isomers of which 353-NP is the most relevant both in terms of abundance (about 20% of total mass) and endocrine potential. 353-NP is metabolised in sewage sludge. The aims of the present study were to determine and to compare the acute toxicity of t-NP, 353-NP and its metabolites as well as to discuss if the toxicity of 353-NP changes during degradation. Materials and methods  353-NP and two of its metabolites were synthesised. The zebrafish embryo test was performed according to standard protocols. Several lethal and non-lethal endpoints during embryonal development were reported. NOEL, LOEL and EC₅₀ were calculated. Results  All tested compounds caused lethal as well as non-lethal malformations during embryo development. 353-NP showed a higher toxicity (EC₅₀ for lethal endpoints 6.7 mg/L) compared to its metabolites 4-(3.5-dimethyl-3-heptyl)-2-nitrophenol (EC₅₀ 13.3 mg/L) and 4-(3,5-dimethyl-3-heptyl)-2-bromophenol (EC₅₀ 27.1 mg/L). Discussion  In surface water, concentrations of NP are far below the NOEC identified by the zebrafish embryo test. However, in soils and sewage sludge, concentrations may reach or even exceed these concentrations. Therefore, sludge-treated sites close to surface waters should be analysed for NP and its metabolites in order to detect an unduly high contamination due to runoff events. Conclusions  The results of the present study point out that the toxicity of 353-NP probably declines during metabolisation in water, sediment and soil, but does not vanish since the major metabolites exhibit a clear toxic potential for zebrafish embryos. Recommendations and perspectives  Metabolites of environmental pollutants should be included in the ecotoxicological test strategy for a proper risk assessment. An erratum to this article can be found at     

Genotoxic potential of selected cytostatic drugs in human and zebrafish cells

Due to their increasing use, the residues of anti-neoplastic drugs have become emerging pollutants in aquatic environments. Most of them directly or indirectly interfere with the cell’s genome, which classifies them into a group of particularly dangerous compounds. The aim of the present study was to conduct a comparative in vitro toxicological characterisation of three commonly used cytostatics with different mechanisms of action (5-fluorouracil [5-FU], cisplatin [CDDP] and etoposide [ET]) towards zebrafish liver (ZFL) cell line, human hepatoma (HepG2) cells and human peripheral blood lymphocytes (HPBLs). Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and acridine orange/ethidium bromide staining. All three drugs induced time- and dose-dependent decreases in cell viability. The sensitivity of ZFL and HepG2 cells towards the cytotoxicity of 5-FU was comparable (half maximal inhibitory concentration (IC₅₀) 5.3 to 10.4 μg/mL). ZFL cells were more sensitive towards ET- (IC₅₀ 0.4 μg/mL) and HepG2 towards CDDP- (IC₅₀ 1.4 μg/mL) induced cytotoxicity. Genotoxicity was determined by comet assay and cytokinesis block micronucleus (CBMN) assay. ZFL cells were the most sensitive, and HPBLs were the least sensitive. In ZFL cells, induction of DNA strand breaks was a more sensitive genotoxicity endpoint than micronuclei (MNi) induction; the lowest effective concentration (LOEC) for DNA strand break induction was 0.001 μg/mL for ET, 0.01 μg/mL for 5-FU and 0.1 μg/mL for CDDP. In HepG2 cells, MNi induction was a more sensitive genotoxicity endpoint. The LOEC values were 0.01 μg/mL for ET, 0.1 μg/mL for 5-FU and 1 μg/mL for CDDP. The higher sensitivity of ZFL cells to cytostatic drugs raises the question of the impact of such compounds in aquatic ecosystem. Since little is known on the effect of such drugs on aquatic organisms, our results demonstrate that ZFL cells provide a relevant and sensitive tool to screen genotoxic potential of environmental pollutant in the frame of hazard assessment.     

DNA damage effect of cyprodinil and thiacloprid in adult zebrafish gills

Cyprodinil and thiacloprid are two of the most commonly used pesticides in Turkey. It is more likely to reach humans or animals due to their widespread use. This study aims to investigate whether there is a DNA damage risk due to cyprodinil and thiacloprid exposure. Zebrafish, which is used as a model organism in health and environmental research, and comet assay were chosen to demonstrate this damage. Ten zebrafish per group were exposed to 2 different concentrations for each pesticides (0.31 and 0.155 mg/L for cyprodinil and 1.64 and 0.82 mg/L for thiacloprid) for 21 days. After, gills were excised and comet assay was performed. Photos of an average of 50 cells per slide were taken and were analyzed with visual evaluation program. DNA damage was found to be increased in the 0.31 mg/L cyprodinil, 0.82 mg/L thiacloprid, and 1.64 mg/L thiacloprid treatment groups when compared to the control group (p < 0.001). Average tail DNA percentage parameter values were 9.45 ± 0.51, 10.30 ± 0.34, 11.17 ± 0.33, and 2.47 ± 0.06 respectively. Cyprodinil and thiacloprid were identified as genotoxic agents that should be investigated further.

     

Toxicological effect of MPA-CdSe QDs exposure on zebrafish embryo and larvae

Cadmium selenium (CdSe) quantum dots (QDs) are semiconductor nanocrystals that hold wide range of applications and substantial production volumes. Due to unique composition and nanoscale properties, their potential toxicity to aquatic organisms has increasingly gained a great amount of interest. However, the impact of CdSe QDs exposure on zebrafish embryo and larvae remains almost unknown. Therefore, the lab study was performed to determine the developmental and behavioral toxicities to zebrafish under continuous exposure to low level CdSe QDs (0.05-31.25 mg L⁻¹) coated with mercaptopropionic acid (MPA). The results showed MPA-CdSe exposure from embryo to larvae stage affected overall fitness. Our findings for the first time revealed that: (1) The 120 h LC₅₀ of MPA-CdSe for zebrafish was 1.98 mg L⁻¹; (2) embryos exposed to MPA-CdSe resulted in malformations incidence and lower hatch rate; (3) abnormal vascular of FLI-1 transgenic zebrafish larvae appeared after exposure to MPA-CdSe including vascular junction, bifurcation, crossing and particle appearance; (4) larvae behavior assessment showed during MPA-CdSe exposure a rapid transition from light-to-dark elicited a similar, brief burst and a higher basal swimming rate; (5) MPA-CdSe induced embryos cell apoptosis in the head and tail region. Results of the observations provide a basic understanding of MPA-CdSe toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism.     

Aerobic metabolism and cardiac activity in the descendants of zebrafish exposed to pyrolytic polycyclic aromatic hydrocarbons

The increase of anthropogenic activities on coastal areas induces discharges of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystem. PAH effects depend not only on their concentration and the way of contamination but also on the different developmental stages of the organism. Zebrafish were exposed to relevant concentration of pyrolytic PAHs from the first meal (i.e., 5-day post fertilization, dpf) to mature adults. Parental effect of this type of exposure was evaluated through the assessment of aerobic metabolic scope, cardiac frequency, and cardiac mRNA expression on larval and/or embryo progeny of contaminated fish. Our results suggest that cardiac frequency increased in larval descendants of fish exposed to the environmental concentration of pyrolytic PAHs (i.e., 5 ng.g^?1 of food), while a lack of effect on aerobic metabolism in 5 dpf larvae was highlighted. A surexpression of mRNA related to the cardiac calcium transporting ATPase atp2a2a, a protein essential for contraction, is in accordance with this increasing cardiac frequency. Even if cardiac development genes cmlc1 and tnnt2a were not affected at early life stages tested, complementary work on cardiac structure could be interesting to better understand PAHs action.     

Maternal transfer of brominated flame retardants in zebrafish (Danio rerio)

In many species reproduction and embryonic development have been shown to be sensitive to environmental contaminants. Understanding embryonic exposure to environmental contaminants is thus highly important. In this study concentrations of brominated flame retardants (BFRs) were measured in zebrafish eggs after parental exposure for 42 days via the diet. Zebrafish were exposed to two doses of eleven structurally-diverse BFRs. Eight BFRs were detected in the female zebrafish and maternal transfer to eggs was evident for all eight compounds. The highest concentrations in eggs were observed for hexabromocyclododecane (HBCD) and 2,4,4'-tribromodiphenyl ether (BDE 28), followed by 2,2',3,4,4',5',6-heptabromodiphenyl ether (BDE 183) and tetrabromobisphenol A 2,3-dibromopropyl ether (TBBPA DBPE). Five potential BFR metabolites were tentatively identified in female fish and maternal transfer was observed also for these compounds. The lipid adjusted concentrations in eggs were significantly higher than the concentrations in female fish for several of the BFRs. Further, the results showed a generally higher transfer in the lower exposure level and also indicated a dependency on the physico-chemical properties of the compounds.     

The effects of henna (hair dye) on the embryonic development of zebrafish (Danio rerio)

The powder of henna is extensively used as decorative skin paint for nail coloring and as a popular hair dye in Asian countries. Its human health risk is extensive, and it is frequently released as waste into the aquatic environment raising the concerns. Zebrafish (Danio rerio) embryos were employed to study the developmental effects of henna. Normal fertilized zebrafish embryos under standard water were selected for the control and test chambers. Three predetermined sublethal concentrations (100, 200, and 275 μM) of henna in 24-well cell culture plates were tested on 1-h postfertilized embryo (pfe) for 96 h. Observation for rates of survival and mortality was recorded; digital camera was used to image morphological anomalies of embryos with a stereomicroscope; and functional abnormalities at 24, 48, 72, and 96 h were performed. The hatching rates of embryos were reduced significantly when treated with 200 and 275 μM or higher concentrations of henna. Slow blood circulation in the whole body was observed with a median effect on hatching exposed to 200 and 275 μM of henna at 48-h pfe. At 72- and 96-h pfe, blood circulation was ceased in the whole body but still had a heartbeat. At 96-h pfe, pericardial sac edema, yolk sac edema, head deformation, spine crooked malformation, and tail malformation (bent tails or hook-like tails) were observed in the surviving larvae at 100 μM. In summary, exposure to henna at 100, 200, and 275 μM causes some altered morphological and physiological abnormalities including increased mortality, hatching delay, slow blood circulation, pericardial sac edema, yolk sac edema, abnormal body axes, twisted notochord, tail deformation, weak heartbeat, and growth retardation and was also detected in some treated embryos and groups having adverse effects on embryonic development of zebrafish provoking potential human developmental risk studies.