Dinitroaniline Herbicides Research Articles

Structural features of carrot α-tubulin predetermining the natural resistance to dinitroaniline herbicides

Aim. To explain the natural resistance of Daucus carota L. to dinitroaniline herbicides. To clarify features of the carrot α-tubulin that may affect formation of the ligand-protein complex based on the structural and electrostatic analysis of the ligand-binding site. Methods. Reconstruction of the spatial structure of α-tubulin from D. carota and Toxoplasma gondii using profile (Swiss-Model) and de-novo (AlphaFold2) modeling. Molecular dynamics (MD) simulations of the built 3D-models in Gromacs. Analysis of the molecular electrostatics with PDB2PQR/APBS tools. Visualization and analysis of molecular structures in PyMOL. Results. It has been shown that along with the typical positive charge of the dinitroaniline-binding pocket, all isotypes of carrot α-tubulin demonstrate negatively charged regions that may cause conflicts with the nitro-groups of the ligands. Also, the MD-stable negatively charged "bridge" between Cys316 and the aryl-fragment of Phe255 was observed in all α-tubulin isotypes. In our opinion, it not only competes with the cyclic fragment of dinitroanilines, but overall prevent the opening of the site pocket in carrot α-tubulin. Conclusions. It was clarified that natural resistance of D. carota to dinitroaniline herbicides may be associated with steric and electrostatic conflicts observed in in all α-tubulin isotypes. In our opinion, it prevents interaction with dinitroaniline compounds at the stage of primary site recognition on the early stages of protein-ligand complex formation.

Evaluation of the performance of dinitroaniline herbicide on growth and yield of soybeans Glycine max L when different planting dates after spraying

Evaluation of the performance of dinitroaniline herbicide on growth and yield of soybeans Glycine max L when different planting dates after spraying

Differences in amino acid composition of carrot α-tubulin potentially confer the resistance to dinitroaniline herbicides

Aim. To reveal the features of amino acid composition of carrot α-tubulin isotypes that potentially determine natural tolerance to dinitroaniline herbicides. Methods. Literature and database search. Comparison of protein sequences and structures: multiple sequence alignment, phylogenetic profiling, protein and ligand structure modeling, etc. Results. Genomic and proteomic analysis of Daucus carota has revealed at least eight unique isotypes of α-tubulin that differ in amino acid sequences and gene loci. Remarkable differences in amino acid composition of the dinitroanilinebinding-like (DBL) region of analyzed α-tubulin have been revealed, which may be the reason of its natural resistance to these compounds. Сonclusions. Differences in amino acids at positions of canonical mutations – Cys4 (TBA1, 2, 3, 6, 7 and 8), Thr53 (TBA6), Ile202 (TBA1 and 7) and Met202 (TBA5), as well as previously undescribed non-canonical substitutions – Ile4 (TBA4 and 5), Cys52 (TBA6), Ser201 (TBA1, 2, 3 and 8) and Val194 (TBA4 and 5), were noted as potentially associated with natural tolerance of the carrot to dinitroaniline herbicides.

Toxic effects of benfluralin on zebrafish embryogenesis via the accumulation of reactive oxygen species and apoptosis

The dinitroaniline herbicide benfluralin is used weed control in conventional systems and poses a high risk of accumulation in aquatic systems. Previous studies have shown the toxic effects of benfluralin on non-target organisms; however, its developmental toxicity in vertebrates has not yet been reported. This study demonstrated the developmental toxicity of benfluralin and its mechanism of action, using zebrafish as an aquatic vertebrate model. Benfluralin induces morphological and physiological alterations in body length, yolk sac, and heart edema. We also demonstrated a reactive oxygen species (ROS) increase of approximately 325.53 % compared with the control group after 20 μM benfluralin-treatment. In addition, the malformation of the heart and vascular structures was identified using transgenic flk1:eGFP zebrafish models at 20 μM concentration benfluralin exposure. Moreover, benfluralin induced small livers, approximately 59.81 % of normal liver size, via abnormal development of the liver as observed in the transgenic L-fabp:dsRed zebrafish. Benfluralin also inhibits normal growth via abnormal expression of cell cycle regulatory genes and increases oxidative stress, inflammation, and apoptosis. Collectively, we elucidated the mechanisms associated with benfluralin toxicity, which lead to various abnormalities and developmental toxicities in zebrafish. Therefore, this study provides information on the parameters used to assess developmental toxicity in other aquatic organisms, such as herbicides, pesticides, and environmental contaminants.

Dissipation dynamics and dietary risk assessment of prodiamine in rice by modified QuEChERS method combined with HPLC-MS

Prodiamine is a dinitroaniline herbicide which can be tried for weed control in rice fields because of its unique mode of action. Its behavior in the rice paddy environment needs to be studied before trying to use. Its dissipation and residues in the paddy environment were studied using HPLC-MS coupled with the modified QuEChERS method to assess the safety of its use in rice plantations. The LOD and LOQ of prodiamine in rice field substrate extracts ranged from 0.0069 to 0.0185 mg/kg and 0.00201–0.00550 mg/kg, respectively. The method exhibited high linearity (R2 ≥ 0.99) within the concentration range of 0.01–5 mg/L. Intra-day and inter-day recoveries ranged from 84.11% to 115.27% with RSDr of 1.29∼7.67% and RSDR of 1.99–7.70%. Meanwhile, the dynamics of prodiamine dissipation in paddy soil and rice plants followed a first-order kinetic model, with the half-life (t0.5) ranging from 11.02 to 14.95 d and 4.81–5.55 d, respectively, indicating a high rate of dissipation. The final residue results showed that the residues in the rice plants of prodiamine at harvest were mainly concentrated on the rice husk. Further chronic dietary risk assessment revealed that the residues of prodiamine in brown rice did not pose any health risk to humans.

α-Tubulin mutation Thr-239-Ile in annual bluegrass (Poa annua) induces variable responses to prodiamine and dithiopyr

AbstractMitotic-inhibiting herbicides, like prodiamine and dithiopyr, are used to control annual bluegrass (Poa annua L.) preemergence in managed turfgrass; however, resistance to mitotic-inhibiting herbicides has evolved due to repeated applications of herbicide from a single mechanism of action. Three suspected resistant populations (R1, R2, and R3) were collected in Alabama and Florida and screened for resistance to prodiamine. Part of the α-tubulin gene was sequenced for known target-site mutations. Target-site mutations were reported in all three R populations, with each containing an amino acid substitution at position 239 from threonine to isoleucine (Thr-239-Ile). Previous research has indicated that the Thr-239-Ile mutation confers resistance to dinitroaniline herbicides in other species. Dose–response screens using prodiamine and dithiopyr were conducted and I50 values were calculated for R1, R2, and R3 using regression models based on seedling emergence. For prodiamine, I50 values for R1, R2, and R3 were 35.3, 502.7, and 91.5 g ai ha−1, respectively, resulting in 2.9-, 41.9-, and 7.6-fold resistance, respectively, when compared with a susceptible (S) population. For dithiopyr, I50 values for R1, R2, and R3 were 154.0, 114.2, and 190.1 g ai ha−1, respectively, resulting in 3.6-, 2.7-, and 4.5-fold resistance, respectively, when compared with an S population. When comparing I90 values with the highest labeled use rates, R2 had a 2.9-fold level of resistance to prodiamine, and R1, R2, and R3 had a 2.4-, 2.0-, and 3.2-fold levels of resistance to dithiopyr, respectively. This is the first report of a variable response in P. annua to prodiamine despite each R population possessing the same mutation.

Fluchloralin induces developmental toxicity in heart, liver, and nervous system during early zebrafish embryogenesis

The zebrafish is a prominent vertebrate model popularly used for toxicity testing because of its rapid development and transparent embryos. Fluchloralin, a dinitroaniline herbicide used to control weeds, inhibits microtubule formation and cell division. The structurally homologous substances ethalfluralin and pendimethalin, which belong to the dinitroaniline family, were found to be genotoxic and to exert developmental toxicity via mitochondrial dysfunction in a zebrafish model. To date, developmental toxicity of fluchloralin in zebrafish has not been reported. In the present study, we identified morphological changes in developing zebrafish, including decreased survival rate and body length, and increased yolk sac edema. In dose-dependent response to fluchloralin exposure, inhibition of neurogenesis in the spinal cord and motor neuron defects were observed in transgenic zebrafish models (olig2:dsRed). Zebrafish exposed to fluchloralin also displayed organ dysfunction in the heart, liver, and pancreas in cmlc2:dsRed and lfabp:dsRed;elastase:GFP transgenic models. Fluchloralin increased cell death in the brain by promoting apoptosis, visualized via acridine orange staining, and by activating apoptosis signaling proteins, including cytochrome c1, zBax, and Bcl-XL. This study provides novel evidence supporting the necessity of controlling pollutants in aquatic environments.

Synthesis and characterization of modified silica nanoparticles based molecularly imprinted polymers as a sensor for selective detection of pendimethalin from drinking water

Pendimethalin (PND) is a dinitroaniline herbicide that inhibits the synthesis of microtubules during cell division to suppress broadleaf weeds. Its widespread agricultural application raises the risk of contamination of underground water supplies. US Environmental Protection Agency (EPA) declared the PND as a possible human carcinogen (group C). This study demonstrated the synthesis of modified silica nanoparticles based molecularly imprinted polymers (MIPs) with a higher affinity for PND, which has been employed for its removal from drinking water. The synthesized PND-MIP was characterized using various techniques, including NMR, ESI, FTIR, AFM, TGA, and DLS. The application of synthesized PND-MIP in the detection of trace PND in drinking water exhibited the excellent performance, high sensitivity, and good selectivity. The observed results revealed the potential of PND-MIP to be used in high throughput sample detection with satisfied results.

Pendimethalin exposure disrupts mitochondrial function and impairs processes related to implantation.

Pendimethalin as a dinitroaniline herbicide is used to eliminate weeds during the cultivation of various crops such as grains, fruits, and vegetables. This study reveals that pendimethalin exposure at various concentrations led to disruption in Ca2+ homeostasis and mitochondrial membrane potential, as well as dysregulation of the mitogen-activated protein kinase signaling pathway and implantation-related genes in porcine trophectoderm and uterine luminal epithelial cells. The use of herbicides is a major control method in agriculture. Pendimethalin (PDM) has been increasingly used as a herbicide for approximately 30 years. PDM has been reported to cause various reproductive problems, but its toxicity mechanism in the pre-implantation stage has not been investigated in detail. Herein, we studied the effects of PDM on porcine trophectoderm (pTr) and uterine luminal epithelial (pLE) cells and identified a PDM-mediated anti-proliferative effect in both cell types. PDM exposure generated intracellular reactive oxygen species, induced excessive Ca2+ influx into mitochondria, and activated mitogen-activated protein kinase signaling pathway. Ca2+ burden resulted in the dysfunction of mitochondria and eventual disruption of Ca2+ homeostasis. Further, PDM-exposed pTr and pLE cells showed cell cycle arrest and programmed cell death. In addition, a decrease in migration ability and dysregulated expression of genes related to the functioning of pTr and pLE cells was evaluated. This study provides insight into time-dependent transitions within the cell environment after PDM exposure and elucidates a detailed mechanism of induced adverse effects. These results imply that PDM exposure can potentially cause toxic effects on the implantation-related process in pigs. Moreover, to the best of our knowledge, this is the first study to describe the mechanism by which PDM induces these effects, enhancing our understanding of the toxicity of this herbicide.

Ethalfluralin induces developmental toxicity in zebrafish via oxidative stress and inflammation

Ethalfluralin, of dinitroaniline herbicide family, is an effective weed controller. Following residue detection in herbicide-treated fields, ethalfluralin was reported to interfere with early stages of implantation in some vertebrate species. However, the role of ethalfluralin in the development of zebrafish embryos has not been elucidated yet. Therefore, in the present study, we investigated the morphological and physiological changes that occur in the embryonic development of zebrafish due to ethalfluralin exposure. Results indicated that ethalfluralin decreased survival rate along with reduction in the hatching ratio and heartbeat. It was observed to cause edema in the heart and yolk sac, and apoptosis in the anterior region of the developing zebrafish larvae; as visualized through acridine orange and TUNEL staining. In addition, ethalfluralin increased the expression of the apoptosis-associated genes including tp53, cyc1, casp8, casp9, and casp3. The Seahorse Mito Stress analysis revealed that ethalfluralin slightly reduced mitochondrial respiration in live zebrafish embryos. Reactive oxygen species (ROS) production was also observed to be elevated in zebrafish larvae in response to ethalfluralin. Treatment with ethalfluralin decreased blood vessel formation in brain and intestine in flk1 transgenic zebrafish embryos. The decrease in angiogenesis related gene expression was specifically observed in vegfc, flt1, and kdrl, and in the intestinal vasculature related genes apoa4a, aqp3, fabp2, and vil1. Moreover, an increase in inflammatory genes such as cox2a, cox2b, cxcl-c1c, il8, mcl1a, mcl1b, and nf-κb was observed using real-time PCR analysis. Collectively, these results indicate that oxidative stress generated by exposure to ethalfluralin induced ROS generation, apoptosis, inflammation and anti-angiogenic effects, and therefore, ethalfluralin may be toxic to the development of zebrafish embryos.

Gold-based strip sensor for the rapid and sensitive detection of butralin in tomatoes and peppers

Butralin is a widely used dinitroaniline herbicide. Butralin residues in vegetables or fruits represent a threat to human health. In this study, we developed a rapid and sensitive gold-based lateral flow immunoassay (LFIA) for butralin detection in tomato and green pepper samples based on a screened monoclonal antibody (mAb) against butralin. The mAb possessed a half-maximal inhibitory concentration (IC50) of 12.7 ng/mL, with no cross-reactivity toward other dinitroaniline herbicides. The established LFIA strip had a visible limit of detection (LOD) of 50 ng/g and a cut-off value of 2000 ng/g in tomato and green pepper samples. According to the calibration curves for quantitative analysis, the calculated LODs of the LFIA strip were 4.7 ng/g and 4.3 ng/g in tomato and green pepper, respectively. The results were obtained within 10 min. The average recoveries ranged between 95.4% and 109.6% with a coefficient of variation (CV) of 4.3% to 7.1% in tomato samples and between 94.8% and 109.1% with a CV of 3.9% to 6.1% in green pepper samples. These data suggested that our proposed LFIA is a sensitive, specific, and reliable method for the rapid detection of butralin in real samples.

Dinitramine induces implantation failure by cell cycle arrest and mitochondrial dysfunction in porcine trophectoderm and luminal epithelial cells

The herbicide market is growing rapidly, as weed control is a significant challenge in agriculture. Many studies have reported the toxicity of herbicides to non-target organisms. Dinitramine is a dinitroaniline herbicide that is particularly toxic to aquatic organisms. However, little is known about the effects of dinitramine on the female reproductive system. Therefore, in the present study, we utilized porcine trophectoderm (pTr) cells and porcine endometrial luminal epithelial (pLE) cells to verify the reproductive toxicity of dinitramine. Dinitramine reduced the viability of both cell types, by triggering cell cycle arrest, especially at the sub-G1 phase, and increasing apoptosis, inhibiting DNA replication. Dinitramine disrupted intracellular calcium homeostasis and induced oxidative stress by producing reactive oxygen species, leading to the loss of mitochondrial membrane potential and alteration of mitochondrial respiration. Mitogen-activated protein kinase pathways were altered, and migration decreased in pTr and pLE cells after dinitramine treatment; the expression of pregnancy-related genes in these cells was decreased. Thus, dinitramine reduced the viability and migratory capacity of both cell types, and this could interrupt the early stages of pregnancy.

Dinitroaniline herbicide pendimethalin affects development and induces biochemical and histological alterations in zebrafish early-life stages

Pendimethalin (PND) is a dinitroaniline preemergent herbicide widely used to control grasses and weeds. The present study aimed to evaluate the PND potential effects on the development of zebrafish early-life stages. The research focuses first on acute toxicity, followed by the integration of toxicity results through histopathology, oxidative status, and neurotoxicity evaluation of sublethal and environmentally relevant concentrations. Zebrafish larvae exposed to PND showed mortality and developed sublethal alterations including impaired fin development, lordosis, scoliosis, blood congestion, impaired blood flow, and reduced heartbeat. PND exposure (0.5 mg/L) affects musculoskeletal development leading to delayed and reduced ossification of the vertebral centra in the developing vertebral column and disruption of muscle morphology. Herbicide exposure (0.5 mg/L and 0.05 mg/L) led also to biochemical changes of antioxidant enzymes, increasing the activity of CAT, GR, and GPx, while no effects were observed on the activity of SOD and GST in zebrafish larvae. Lastly, AChE activity, a biochemical marker of neurotoxicity, was also increased in zebrafish larvae exposed to 0.5 mg/L of PND. These results confirm the developmental toxicity of PND in zebrafish early-life stages, pointing out the potential role of oxidative stress in the onset of sublethal alterations.

A dinitroaniline herbicide resistance mutation can be nearly lethal to plants.

Lolium rigidum is the most important weed in Australian agriculture and pre-emergence dinitroaniline herbicides (e.g., trifluralin) are widely and persistently used for Lolium control. Consequently, evolution of resistance to dinitroaniline herbicides has been increasingly reported. Resistance-endowing target-site α-tubulin gene mutations are identified with varying frequency. This study investigated the putative fitness cost associated with the common resistance mutation Val-202-Phe and the rare resistance mutation Arg-243-Met causing helical plant growth. Results showed a deleterious effect of Arg-243-Met on fitness when plants are homozygous for this mutation. This was evidenced as high plant mortality, severely diminished root and aboveground vegetative growth (lower relative growth rate), and very poor fecundity compared with the wild-type, which led to a nearly lethal fitness cost of >99.9% in competition with a wheat crop. A fitness penalty in vegetative growth was evident, but to a much lesser extent, in plants heterozygous for the Arg-243-Met mutation. By contrast, plants possessing the Val-202-Phe mutation exhibited a fitness advantage in vegetative and reproductive growth. The α-tubulin mutations Arg-243-Met and Val-202-Phe have contrasting effects on fitness. These results help understand the absence of plants homozygous for the Arg-243-Met mutation and the high frequency of plants carrying the Val-202-Phe mutation in dinitroaniline-resistant L. rigidum populations. The α-tubulin Arg-243-Met mutation can have an exceptional fitness cost with nearly lethal effects on resistant L. rigidum plants. © 2022 Society of Chemical Industry.

Gold nanoparticle-based lateral flow immunoassay for the rapid detection of flumetralin in orange.

Residues of flumetralin, a dinitroaniline herbicide, in foods pose a health risk to humans. In this study, we produced a sensitive monoclonal antibody (mAb) against flumetralin and developed a gold nanoparticle-based lateral flow immunoassay (LFIA) strip for screening flumetralin in orange. The subtype of mAb 3F5 was IgG1 and had a half-maximal inhibitory concentration of 9.43 ng mL-1. The cross-reactivity assay indicated that mAb had good specificity. The LFIA strip had a visual limit of detection of 200 ng g-1 in orange. We obtained results with the naked eye within 15 min. The calculated LOD of the strip in orange was 33.26 ng g-1, with a linear detection of 80.72-1672.10 ng g-1. The strip had recovery rates ranging from 98.4% to 110.1%. Therefore, our developed method is an effective and reliable tool for the rapid detection of flumetralin in orange.

Benchmark dose and the adverse effects of exposure to pendimethalin at low dose in female rats.

Pendimethalin (PND) is a dinitroaniline herbicide widely used to control broadleaf and annual grasses. Although the acute oral toxicity of PND is >5g/kg b.wt. in humans (LD50 for rats >5000 g/kg b.wt.), it has been classified as a possible human carcinogen. It is still used in agriculture so agricultural workers and their families, as well as consumers, can be exposed to this herbicide. The present study is the first report investigating the dose-response effect using the benchmark dose (BMD) and the adverse effects of exposure to PND at low dose via apoptosis responses linked to the expression of tumour necrosis factor-α (TNF-α), FAS and BAX proteins; oxidative stress; and DNA and liver damage in female rats. The rats were exposed to PND via drinking water at doses equivalent to no-observed-adverse-effect level (NOAEL = 100 mg/kg b.wt.), 200 and 400 mg/kg b.wt. for 28 days. PND caused the overexpression of TNF-α, FAS and BAX; increased the levels of serum liver biomarkers; and increased oxidative stress in the liver and erythrocytes. Furthermore, it induced DNA and liver damage in a dose-dependent manner. The BMD showed that serum alkaline phosphatase (ALP) and total antioxidant capacity (78.4 and 30.1mg/kg b.wt./day, respectively), lipid peroxidation in liver tissue (30.9mg/kg b.wt./day), catalase in erythrocytes (14.0mg/kg b.wt./day) and FAS expression in liver tissue (6.89 mg/kg b.wt./day) were highly sensitive biomarkers of PND toxicity. Our findings suggest the generation of reactive oxygen species as a possible mechanism of PND-induced gene overexpression of tumour necrosis factor-α (TNF-α), FAS and BAX proteins, oxidative stress and DNA and liver damage in female rats.

Target-site resistance to trifluralin is more prevalent in annual ryegrass populations from Western Australia.

Trifluralin is widely used in Australia as one of the important pre-emergence herbicides to control annual ryegrass (Lolium rigidum Gaud.) populations. Trifluralin resistance evolution and mechanisms have been identified in some ryegrass populations. In this study, 21 putative resistant field survey populations from Western Australian were screened with trifluralin, and 90% (19 of 21) contained individuals surviving 480 g ha-1 trifluralin treatment. Twelve populations contained individuals possessing the known α-tubulin resistance mutations at Val-202, Thr-239 and Arg-243 in TUA4 (alpha-tubulin 4 n), plus multiple potential resistance mutations in TUA4 pending genetic confirmation. Three populations had only individuals carrying newly identified (but uncharacterized) mutations in TUA3/TUA4. Radioactive work found that six populations evolved metabolic resistance to trifluralin, and at least four of them also possessed the known and/or putative target-site mutations. These results confirm that a high incidence of resistance to the dinitroaniline herbicide (trifluralin) is present, and target-site tubulin mutations make a major contribution to resistance in these annual ryegrass populations. Co-evolution of both target-site and non-target-site resistance to per-emergence herbicides warrants diverse management tactics.

Toxicity and tissue accumulation characteristics of the herbicide pendimethalin under silicon application in ginger (Zingiber officinale Roscoe).

Environmental health and food safety issues potentially caused by the dinitroaniline herbicide pendimethalin (PM) are a worldwide concern. The toxicity response of ginger and tissue accumulation effects of PM on ginger biomass were studied by utilizing PM (CK (clean water), PM1 (0.4%), PM2 (0.67%), PM3 (1.0%), and PM4 (1.67%)) in a dose-response study. It significantly reduced the biomass of ginger under PM4, which is attributed to root damage. The net photosynthetic rate of ginger under PM4 was 11.37% lower than that of CK, which is mainly caused by stomatal limitation. In addition, the ultrastructure of chloroplasts has changed. PM4 caused the accumulation of reactive oxygen species (ROS) in ginger. The activity of superoxide dismutase (SOD) and peroxidase (POD) increased accordingly, maintaining the dynamic balance of ROS content. PM had no significant effect on the expression of ginger α-tubulin genes. PM was significantly accumulated in ginger roots, but not rhizomes. Si increased the productivity of ginger under PM4, which is mainly related to the increase of root development (root application of silicon) and photosynthetic efficiency (foliar application of silicon). Si reduced the ROS content due to the increase in SOD, POD, and catalase (CAT) activity and photosynthetic efficiency.

Assessing sub-lethal effects of the dinitroaniline herbicide pendimethalin in zebrafish embryos/larvae (Danio rerio)

Pendimethalin is a dinitroaniline herbicide used to control broadleaf weeds by inhibiting the formation of microtubules during cell division. Its use on a variety of crops leads to its potential entry into aquatic environments, but little is known about its sub-lethal toxicity to early developmental stages of aquatic vertebrates. To address this knowledge gap, we assessed the toxicity of pendimethalin to zebrafish embryos and larvae by measuring mortality, developmental abnormalities, oxidative respiration, reactive oxygen species, gene expression, and locomotor activity following exposure to the herbicide throughout early development. Embryos at ~6 h post-fertilization (hpf) were exposed to either a solvent control (0.1% DMSO, v/v), embryo rearing medium (ERM), or one dose of either 1, 2.5, 5, or 25 μM pendimethalin for up to 7-days post fertilization depending on the bioassay. Exposure to 25 μM pendimethalin resulted in high prevalence of spinal curvature, tail malformations, pericardial edema, and yolk sac edema at 4 dpf, while exposure to 5 μM pendimethalin induced pericardial edema and lordosis in the fish exposed over 7 dpf. Exposure to pendimethalin up to 5 μM did not negatively impact oxidative respiration (e.g., basal respiration, oligomycin-induced ATP production) in embryos following a 24-h exposure. Pendimethalin did not induce reactive oxygen species at concentrations of 1–5 μM. Levels of transcripts associated with oxidative respiration and damage response were altered in 7d-larvae; cox1 mRNA was increased in larvae fish exposed to 1 μM while cox5a1 and sod2 mRNA were decreased with 2.5 μM exposure. The Visual Motor Response (VMR) test for light-dark response revealed that larval activity in the dark period was reduced for zebrafish exposed to >1 μM pendimethalin compared to ERM and DMSO solvent control groups. These data inform on the sub-lethal toxicity of pendimethalin to early stages of fish embryos and larvae.

Dinitramine induces cardiotoxicity and morphological alterations on zebrafish embryo development.

Dinitramine (DN), an herbicide in the dinitroaniline family, is used in agricultural areas to prevent unwanted plant growth. Dinitroaniline herbicides inhibit cell division by preventing microtubulin synthesis. They are strongly absorbed by the soil and can contaminate groundwater; however, the mode of action of these herbicides in non-target organisms remains unclear. In this study, we examined the developmental toxicity of DN in zebrafish embryos exposed to 1.6, 3.2, and 6.4 mg/L DN, compared to embryos exposed to DMSO (control) for 96 h. Visual assessments using transgenic zebrafish (fli1:eGFP) indicated abnormal cardiac development with enlarged ventricles and atria, decreased heartbeats, and impaired cardiac function. Along with cardiac development, vessel formation and angiogenesis were suppressed through activation of the inflammatory response. In addition, exposure to 6.4 mg/L DN for 96 h induced cell death, with upregulation of genes related to apoptosis. Our results showed that DN induced morphological changes and triggered an inflammatory response and apoptotic cell death that can impair embryonic growth and survival, providing an important mechanism of DN in aquatic organisms.