Developmental defects induced by thiabendazole are mediated via apoptosis, oxidative stress and alteration in PI3K/Akt and MAPK pathways in zebrafish

Effects of 2,4,6-Trichloroanisole on the morphological development and motility of zebrafish

2,4,6-Trichloroanisole (2,4,6-TCA), a compound with a characteristic earthy odor, is a common source of odorous pollutants in drinking water and wine. However, research on its biological toxicity is limited. In this study, we used zebrafish as an indicator model to investigate the effects of 2,4,6-TCA exposure on morphological development, oxidative stress, apoptosis, heart rate, blood flow, and motility. We found that exposure to 2,4,6-TCA resulted in significant spinal, tail, and cardiac deformities in zebrafish larvae and promoted a pronounced oxidative stress response and extensive cell apoptosis, notably in the digestive tract, head, spine, and heart, ultimately leading to significant reductions in zebrafish heart rate, blood flow, and motility. Moreover, these effects became more pronounced with an increase in the concentration of 2,4,6-TCA to which the zebrafish were exposed. Furthermore, qPCR analysis revealed that exposure to 2,4,6-TCA promoted significant changes in the expression levels of genes associated with oxidative stress, apoptosis, cardiac development, and the nervous system, particularly key genes (p53, apaf1, casp9, and casp3) in the mitochondrial apoptotic pathway, which were significantly upregulated. Similarly, we detected significant upregulation of ache gene expression. These findings indicated that exposure to 2,4,6-TCA resulted in the accumulation of reactive oxygen species in zebrafish, induced strong oxidative stress responses, and triggered lipid peroxidation and extensive cell apoptosis. Cellular apoptosis, which mitochondrial signaling pathways may mediate, has been found to lead to malformations in zebrafish embryos, resulting in significant reductions in cardiac function and motility. To our knowledge, this is the first systematic assessment of the toxicity of 2,4,6-TCA, and our findings provide an important reference for risk assessment and early warning of 2,4,6-TCA exposure.

Evaluation of organ developmental toxicity of environmental toxicants using zebrafish embryos

There is increasing global concern about environmental pollutants, such as heavy metals, plastics, pharmaceuticals, personal care products (PPCPs), and pesticides, which have been detected in a variety of environments and are likely to be exposed to non-target organisms, including humans. Various animal models have been utilized for toxicity assessment, and zebrafish are particularly valuable for studying the toxicity of various compounds owing to their similarity to other aquatic organisms and 70% genetic similarity to humans. Their development is easy to observe, and transgenic models for organs such as the heart, liver, blood vessels, and nervous system enable efficient studies of organ-specific toxicity. This suggests that zebrafish are a valuable tool for evaluating toxicity in specific organs and forecasting the potential impacts on other non-target species. This review describes organ toxicity caused by various toxic substances and their mechanisms in zebrafish.

Propanil impairs organ development in zebrafish by inducing apoptosis and inhibiting mitochondrial respiration

Propanil, an anilide herbicide, has frequently been detected in surface waters in Europe and the United States, largely due to its use in paddy cultivation areas. Particularly in specific regions like Sri Lanka, propanil is considered a potential cause of certain diseases and toxicities due to its high environmental runoff; however, there has been little research on its developmental toxicity. In the present study, we confirmed the developmental toxicity of propanil in zebrafish embryos exposed to 0, 2, 5, and 6 mg/L based on the LC50 value. Propanil exposure in embryos induced morphological changes, including decreased body length and eye size, and increased the heart and yolk sac edema. It increased the number of apoptotic cells in the brains and eyes of zebrafish larvae by 214 % and 184 %, respectively. Propanil-treated embryos exhibited altered mitochondrial metabolism, reducing basal respiration by 28 %, maximal respiration by 24 %, and ATP production by 38 %. These alterations induced organ defects in transgenic zebrafish models (cmlc2:DsRed, flk1:EGFP, olig2:DsRed, lfabp:DsRed;elastase:EGFP, and insulin:EGFP). It induced cardiovascular toxicity, as confirmed by the reduced atrial area, cerebrovascular intensity, and intersegmental vessels. Additionally, propanil decreased the fluorescence intensity of neurons, liver, and pancreas. Collectively, this study indicates that propanil causes early developmental toxicity through apoptosis and mitochondrial dysfunction. It presents a new perspective on how mitochondrial dysfunction, previously unreported in toxicity studies of other anilide herbicides, may affect developmental toxicity.

Necrostatin-1 as a Potential Anticonvulsant: Insights from Zebrafish Larvae Model of PTZ-Induced Seizures

Epilepsy is a common neurological disorder affecting around 70 million people worldwide. Despite significant research and advancements in pharmaceutical therapies, the exact mechanisms underlying epileptogenesis remain unclear. As a result, current antiepileptic drug treatments are ineffective for approximately 30% of patients, providing only symptomatic relief. The epileptic process is influenced by the signaling of tumor necrosis factor alpha (TNFα), which affects neuronal excitability. The TNFα/TNFR1 signaling pathway and the role of RIPK1 in initiating inflammatory cell death pathways are well studied in human disorders. Dysregulation of RIPK1 is linked to inflammation and neurodegenerative diseases. Necrostatin-1 (Nec-1) selectively inhibits RIPK1 in various pathological conditions. The current study aimed to investigate the anticonvulsant properties of Nec-1 (a selective RIPK1 inhibitor) in PTZ-induced seizures in zebrafish larvae. Before the onset of seizures, zebrafish were treated with Nec-1 (15 µM) for 24 h at 6 days post-fertilization (dpf), followed by exposure to 15 mM of PTZ for 30 min. Behavioral assessments were conducted to observe changes in locomotor activity. Additionally, c-Fos expression was measured as an indicator of neuronal activation and analyzed mRNA levels of the astrocyte activation marker (GFAP) along with various inflammatory cytokines. Western blot analysis was conducted to evaluate GABAA receptor expression. Pretreatment with Nec-1 restored normal behavior and reversed the expression of c-Fos in zebrafish larvae induced by PTZ. Additionally, Nec-1 reduced the elevated mRNA expression of inflammatory cytokines and significantly suppressed TNF/TNFR1 signaling, thereby inhibiting the enhanced internalization of GABAA receptors. Our findings indicate that Nec-1 reduced the severity of PTZ-induced seizures in zebrafish by regulating behavior changes, suppressing inflammatory mediators, and enhancing the expression of GABAA receptors, suggesting potential anticonvulsant properties.

Synthetic and Natural Antifungal Substances in Cereal Grain Protection: A Review of Bright and Dark Sides

Molds pose a severe challenge to agriculture because they cause very large crop losses. For this reason, synthetic fungicides have been used for a long time. Without adequate protection against pests and various pathogens, crop losses could be as high as 30-40%. However, concerns mainly about the environmental impact of synthetic antifungals and human health risk have prompted a search for natural alternatives. But do natural remedies only have advantages? This article reviews the current state of knowledge on the use of antifungal substances in agriculture to protect seeds against phytopathogens. The advantages and disadvantages of using both synthetic and natural fungicides to protect cereal grains were discussed, indicating specific examples and mechanisms of action. The possibilities of an integrated control approach, combining cultural, biological, and chemical methods are described, constituting a holistic strategy for sustainable mold management in the grain industry.

Polystyrene nanoplastics synergistically exacerbate diclofenac toxicity in embryonic development and the health of adult zebrafish

In this study, we investigated the possible ecotoxicological effect of co-exposure to polystyrene nanoplastics (PS-NPs) and diclofenac (DCF) in zebrafish (Danio rerio). After six days of exposure, we noticed that the co-exposure to PS-NP (100 μg/L) and DCF (at 50 and 500 μg/L) decreased the hatching rate and increased the mortality rate compared to the control group. Furthermore, we noted that larvae exposed to combined pollutants showed a higher frequency of morphological abnormalities and increased oxidative stress, apoptosis, and lipid peroxidation. In adults, superoxide dismutase and catalase activities were also impaired in the intestine, and the co-exposure groups showed more histopathological alterations. Furthermore, the TNF-α, COX-2, and IL-1β expressions were significantly upregulated in the adult zebrafish co-exposed to pollutants. Based on these findings, the co-exposure to PS-NPs and DCF has shown an adverse effect on the intestinal region, supporting the notion that PS-NPs synergistically exacerbate DCF toxicity in zebrafish.

Inhibitory Activity Against Rhizoctonia Solani and Chemical Composition of Extract from Moutan Cortex

Rice sheath blight (RSB), caused by Rhizoctonia solani, is a significant disease of rice. The negative effects of chemical fungicides have created an urgent need for low-toxicity botanical fungicides. Our previous research revealed that the ethanol crude extract of Moutan Cortex (MC) exhibited superior antifungal activity against R. solani at 1000 μg/mL, resulting in a 100 % inhibition rate. The antifungal properties were mainly found in the petroleum ether extract. However, the active ingredients of the extract are still unclear. In this study, gas chromatography-mass spectrometry (GC-MS) was utilised for the analysis of its chemical components. The mycelium growth rate method was utilized to detect the antifungal activity. The findings indicated that paeonol constituted the primary active component, with a content of more than 96 %. Meanwhile, paeonol was the most significant antifungal active ingredient, the antifungal activity of paeonol (EC50=44.83 μg/mL) was much higher than that of β-sitosterol and ethyl propionate against R. solani. Observation under an optical microscope revealed that paeonol resulted in abnormal mycelial morphology. This study provided theoretical support for identifying monomer antifungal compounds and developing biological fungicides for R. solani.

Antifungal drugs in the aquatic environment: A review on sources, occurrence, toxicity, health effects, removal strategies and future challenges

Fungal infections pose a significant global health burden, resulting in millions of severe cases and deaths annually. The escalating demand for effective antifungal treatments has led to a rise in the wholesale distribution of antifungal drugs, which consequently has led to their release into the environment, posing a threat to ecosystems and human health. This article aims to provide a comprehensive review of the presence and distribution of antifungal drugs in the environment, evaluate their potential ecological and health risks, and assess current methods for their removal. Reviewed studies from 2010 to 2023 period have revealed the widespread occurrence of 19 various antifungals in natural waters and other matrices at alarmingly high concentrations. Due to the inefficiency of conventional water treatment in removing these compounds, advanced oxidation processes, membrane filtration, and adsorption techniques have been developed as promising decontamination methods.In conclusion, this review emphasizes the urgent need for a comprehensive understanding of the presence, fate, and removal of antifungal drugs in the environment. By addressing the current knowledge gaps and exploring future prospects, this study contributes to the development of strategies for mitigating the environmental impact of antifungal drugs and protecting ecosystems and human health.

Association of pesticide exposure with neurobehavioral outcomes among avocado farmworkers in Mexico

BACKGROUND AND AIM

To date, few studies have focused on the health effects of pesticide exposure among avocado farmworkers. We examined the association of exposure to insecticides, fungicides, and herbicides with cognitive and mental health outcomes among these avocado workers from Michoacan, Mexico.

MATERIALS AND METHODS

We conducted a cross-sectional study of 105 avocado farmworkers between May and August 2021. We collected data on self-reported pesticide use during the 12 months prior to the baseline survey and estimated annual exposure-intensity scores (EIS) using a semi-quantitative exposure algorithm. We calculated specific gravity adjusted average concentrations of 12 insecticide, fungicide, or herbicide metabolites measured in urine samples collected during two study visits (8-10 weeks apart). We assessed participants' cognitive function and psychological distress using the NIH Toolbox Cognition Battery and the Brief Symptom Inventory 18 (BSI-18), respectively. We examined individual associations of EIS and urinary pesticide metabolites with neurobehavioral outcomes using generalized linear regression models. We also implemented Bayesian Weighted Quantile Sum (BWQS) regression to evaluate the association between a pesticide metabolite mixture and neurobehavioral outcomes.

RESULTS

In individual models, after adjusting for multiple comparisons, higher concentrations of hydroxy-tebuconazole (OH-TEB, metabolite of fungicide tebuconazole) were associated with higher anxiety (IRR per two-fold increase in concentrations = 1.26, 95% CI:1.08, 1.48) and Global Severity Index (GSI) (IRR = 1.89, 95% CI:1.36, 2.75) scores, whereas higher concentrations of 3,5,6-trichloro-2-pyridinol (TCPy, metabolite of chlorpyrifos) were associated with lower GSI scores (IRR = 0.69, 95% CI: 0.56, 0.85). In BWQS analyses, we found evidence of a mixture association of urinary pesticide metabolites with higher anxiety (IRR = 1.72, 95% CrI: 1.12, 2.55), depression (IRR = 4.60, 95% CrI: 2.19, 9.43), and GSI (IRR = 1.99, 95% CrI: 1.39, 2.79) scores. OH-TEB and hydroxy-thiabendazole (metabolite of fungicide thiabendazole) combined contributed 54%, 40%, and 54% to the mixture effect in the anxiety symptoms, depression symptoms, and overall psychological distress models, respectively.

CONCLUSIONS

We found that exposure to tebuconazole and thiabendazole, fungicides whose effects have been rarely studied in humans, may be associated with increased psychological distress among avocado farmworkers. We also observed that exposure to chlorpyrifos may be associated with decreased psychological distress.

The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics

An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.

Dimethenamid promotes oxidative stress and apoptosis leading to cardiovascular, hepatic, and pancreatic toxicities in zebrafish embryo

Dimethenamid, one of the acetamide herbicides, is widely used on soybeans and corns to inhibit weed growth. Although other acetamide herbicides have been reported to have several toxicities in non-target organisms including developmental toxicity, the toxicity of dimethenamid has not yet been studied. In this research, we utilized the zebrafish animal model to verify the developmental toxicity of dimethenamid. It not only led to morphological abnormalities in zebrafish larvae but also reduced their viability. ROS production and inflammation responses were promoted in zebrafish larvae. Also, uncontrolled apoptosis occurred when the gene expression level related to the cell cycle and apoptosis was altered by dimethenamid. These changes resulted in toxicities in the cardiovascular system, liver, and pancreas are observed in transgenic zebrafish models including fli1a:EGFP and L-fabp:dsRed;elastase:GFP. Dimethenamid triggered morphological defects in the heart and vasculature by altering the mRNA levels related to cardiovascular development. The liver and pancreas were also damaged through not only the changes of their morphology but also through the dysregulation in their function related to metabolic activity. This study shows the developmental defects induced by dimethenamid in zebrafish larvae and the possibility of toxicity in other non-target organisms.

LTe2 induces cell apoptosis in multiple myeloma by suppressing AKT phosphorylation at Thr308 and Ser473

Multiple myeloma (MM) is a highly heterogeneous hematological malignancy originating from B lymphocytes, with a high recurrence rate primarily due to drug resistance. 2-((1H-indol-3-yl)methyl)-3-((3-((1H-indol-3-yl)methyl)-1H-indol-2-yl)methyl)-1H-indole (LTe2), a tetrameric indole oligomer, possesses a wide range of anticancer activities through various mechanisms. Here, we aim to explore the anti-tumor efficiency and potential downstream targets of LTe2 in MM. Its bioactivity was assessed by employing MTT assays, flow cytometry, and the 5TMM3VT mouse model. Additionally, transcriptomic RNA-seq analysis and molecular dynamics (MD) experiments were conducted to elucidate the mechanism underlying LTe2 induced MM cell apoptosis. The results demonstrated that LTe2 significantly inhibited MM cell proliferation both in vitro and in vivo, and revealed that LTe2 exerts its effect by inhibiting the phosphorylation of AKT at the Thr308 and Ser473 sites. In summary, our findings highlight the potential of LTe2 as a novel candidate drug for MM treatment and provided a solid foundation for future clinical trials involving LTe2.