Aclonifen causes developmental abnormalities in zebrafish embryos through mitochondrial dysfunction and oxidative stress

Toxic endpoints or ubiquitous expression?

This opinion article questions the underlying causes of malformations observed in early developmental stages of zebrafish exposed to a range of chemicals. The research focuses on determining whether these developmental abnormalities arise due to the inherent sensitivity of zebrafish to chemical exposure or if they are related to the ubiquitous expression of certain genes within the zebrafish genome. By analysing different studies on zebrafish embryos to various chemical agents and analysing the resulting malformations, the study aims to differentiate between the effects of chemical sensitivity and the role of gene expression in developmental disruptions. Findings from this investigation will contribute to a deeper understanding of the mechanisms driving developmental toxicity in zebrafish, with implications for broader environmental and genetic research.

Impact of sub-lethal Aclonifen intoxication on biochemical and stress markers on Oncorhynchus mykiss: an integrative assessment of multi-biomarker responses

Aclonifen is a diphenyl ether herbicide being included in the list of priority substances. Nevertheless, the data related to its sublethal effects on fish are limited. Therefore, the present study has been carried out to investigate the toxic effects of aclonifen in juvenile Oncorhynchus mykiss following 24, 48, 72 and 96 hours of application to sublethal concentrations of 12.7, 63.5 and 127 μg/L. The application resulted in altered blood biochemistry appearing as hyperglycemia, decreased cholesterol and induced activities of transaminases of ALT and AST. The inhibition of AChE in brain, gill and liver was unimportant revealing its weak potential as anticholinesterase. The induction recorded for SOD, CAT, GPx and GST activities was accompanied with sustained elevation in TBARS and PC levels. It demonstrates both the pro-oxidant potential of aclonifen and oxidation of lipid and proteins resulting in the loss of membrane integrity and protein function. Hyperglycemic condition and decreased protein levels in gill and liver might be proposed as general adaptive responses to compensate increased energy demand. The integrative assessment of multi-biomarker responses shows concentration and duration related rise in calculated indexes. CAT, PC and SOD achieved the maximum scores for brain, gill and liver, respectively. Considering the results, oxidative stress inducing potential and weak anticholinesterase activity along with its disturbing impact on blood biochemistry were evidenced. Moreover, adverse affects observed after short term application on O. mykiss, present the potential risk aclonifen may cause at population level in aquatic ecosystems emphasizing the importance of pesticide regulations to avoid adverse impacts on non-target species.

Oseltamivir phosphate (Tamiflu) alters neurobehavior of zebrafish larvae by inducing mitochondrial dysfunction

Antiviral drugs are widely used, yet their potential risks during early development, particularly within the central nervous system, remain contentious. Oseltamivir phosphate (OSE), a commonly prescribed antiviral, is increasingly detected in various environments. However, its toxicity to organisms and the underlying mechanisms are not well understood. In this study, we employed the zebrafish model to evaluate the developmental neurotoxic effects of OSE at environmentally and therapeutically relevant doses, through high-throughput behavioral analysis, in vivo two-photon imaging, transcriptomic sequencing, pharmacological intervention, and biochemical and molecular assays. Our results indicated that OSE exposure increased heart rate and induced pericardial edema in zebrafish larvae. Additionally, OSE-exposed larvae exhibited hyperactive behavior, impaired social interactions, and reduced habitual learning capacity. Although OSE at our selected levels did not significantly affect neuron count in the brain, it activated neuroinflammatory responses, altered blood vessel morphology, modulated neurotransmitter levels and the expression of neurodevelopment-related genes. Transcriptomic analysis revealed upregulation of mitochondria-related genes associated with oxidative phosphorylation. Further assessments of mitochondrial function demonstrated altered activities of respiratory chain complexes, reduced mitochondrial membrane potential (MMP), and decreased ATP content. Notably, co-treatment with mitochondrial protectants acetyl-l-carnitine-hydrochloride (ALC) or nicotinamide riboside (NR) effectively mitigated OSE-induced neurobehavioral disorders. These findings suggest that overuse of OSE can pose neurodevelopmental risks for both humans and animals, potentially attributable to mitochondrial dysfunction.

Aged polystyrene microplastics exposure affects apoptosis via inducing mitochondrial dysfunction and oxidative stress in early life of zebrafish

In recent years, the toxic effects of microplastics (MPs) on aquatic organisms have been increasingly recognized. However, the developmental toxicity and underlying mechanisms of photoaged MPs at environmental concentrations remain unclear. Therefore, the photodegradation of pristine polystyrene (P-PS) under UV irradiation was used to investigate, as well as the developmental toxicity and underlying mechanisms of zebrafish (Danio rerio) exposed to P-PS and aged polystyrene (A-PS) at environmentally relevant concentrations (0.1-100 μg/L). Mortality, heart rate, body length, and tail coiling frequency of zebrafish larvae were the developmental toxicity endpoints. A-PS had increased crystallinity, the introduction of new functional groups, and higher oxygen content after UV-photoaging. The toxicity results showed that exposure to A-PS resulted in more adverse developmental toxicity than exposure to P-PS. Exposure to A-PS induced oxidative damage, as evidenced by elevated production of reactive oxygen species (ROS) and DNA damage, and led to decreased mitochondrial membrane potential (MMP) and causes the release of cytochrome c (cyt c) from the mitochondria. The caspase-3/-9 activation signaling pathways may cause developmental toxicity via mitochondrial apoptosis. Significant changes in the expression of genes were further explored linking with oxidative stress, mitochondria dysfunctions and apoptosis pathways following A-PS exposure. These findings underscore the importance of addressing the environmental applications of aged MPs and call for further research to mitigate their potential risks on aquatic ecosystems and human health.

Bifenox induces hepatotoxicity and vascular toxicity in zebrafish embryos via ROS production and alterations in signaling pathways

Existing evidence shows that currently used pesticides pose toxicological risks to exposed wildlife. Chemically, bifenox belongs to diphenyl ethers, a well-known group of herbicides. Its mechanism of action primarily involves inducing lipid peroxidation and blocking protoporphyrinogen oxidases. Toxicity of diphenyl ether herbicides has been elucidated in animal cells; however, in vivo toxicological evaluations of bifenox are required to determine its unexpected effects. This study aimed to determine the negative effects of bifenox, and its effects on higher eukaryotes. We found that early stages of zebrafish embryo exposed to bifenox demonstrated increased mortality and physiological defects, based on the LC50 value. Bifenox severely inhibited blood vessel growth by reducing key elements of complex connectivity; fluorescently tagged transgenic lines (fli1a:EGFP) showed morphological changes. Additionally, transgenic lines that selectively identified hepatocytes (fabp10a:DsRed) showed reduced fluorescence, indicating that bifenox may inhibit liver development. To evaluate the level of oxidative stress, we used 2',7'-dichlorofluorescein diacetate (DCFH-DA) probes in zebrafish embryos to identify the underlying mechanisms causing developmental damage. Our findings demonstrate that exposure to bifenox causes abnormalities in the hepatic and cardiovascular systems during zebrafish embryogenesis. Therefore, this study provides new information for the evaluation of toxicological risks of bifenox in vertebrates.

Low toxicity of magnetite-based modified bionanocomposites with potential application for wastewater treatment: Evaluation in a zebrafish animal model

In recent years, the escalating concerns surrounding environmental pollution and the need for sustainable wastewater treatment solutions have underscored the significance of developing technologies that can efficiently treat wastewater while also reducing negative ecological effects. In this context, our study aims to contribute to the advancement of sustainable technologies for wastewater treatment, by investigating the effects that bare magnetite nanoparticles and those functionalized with the enzyme laccase could have in an aquatic animal, zebrafish, at various life cycle stages. Exposure to magnetite nanoparticles shows some effects on embryo hatching, survival rates, or larval behavior at higher concentrations. For both treatments, the hatching percentages were close to 80% compared to 93% for the control group. At the end of the observations in larvae, survival in all the evaluated groups was higher than 90%. Additionally, we evaluated the accumulation of nanoparticles in various stages of zebrafish. We found that, although there was accumulation during embryonic stages, it did not affect normal development or subsequent hatching. Iron levels in different organs such as gills, muscles, gastrointestinal tract, and brain were also evaluated in adults. Animals treated with a mix of food and nanoparticles at 10 μg/mL (Food group) presented a higher concentration of iron accumulation in muscle, gastrointestinal tract, and gills compared to the untreated control group. Although iron levels increased depending on the dose and exposure method applied, they were not statistically significant from the control groups. Our findings suggest that bionanocomposites evaluated here can be considered safe for removal of contaminants in wastewater without toxic effects or detrimental accumulation fish's health.

Mechanisms of female reproductive toxicity in pigs induced by exposure to environmental pollutants

Environmental pollutants, including endocrine disruptors, heavy metals, nanomaterials, and pesticides, have been detected in various ecosystems and are of growing global concern. The potential for toxicity to non-target organisms has consistently been raised and is being studied using various animal models. In this review, we focus on pesticides frequently detected in the environment and investigate their potential exposure to livestock. Owing to the reproductive similarities between humans and pigs, various in vitro porcine models, such as porcine oocytes, trophectoderm cells, and luminal epithelial cells, are used to verify reproductive toxicity. These cell lines are being used to study the toxic mechanisms induced by various environmental toxicants, including organophosphate insecticides, pyrethroid insecticides, dinitroaniline herbicides, and diphenyl ether herbicides, which persist in the environment and threaten livestock health. Collectively, these results indicate that these pesticides can induce female reproductive toxicity in pigs and suggest the possibility of adverse effects on other livestock species. These results also indicate possible reproductive toxicity in humans, which requires further investigation.

High-Resolution Respirometry for the Assessment of Teratogenic Chemicals

Pesticides are often used in agriculture and residential areas to mitigate pests and weeds. These chemicals can enter aquatic ecosystems via runoff and rain events, exerting negative effects on aquatic species. In rapidly developing fish embryos, metabolic disruption can alter the developmental trajectory and alter ATP levels. Therefore, it is important to quantify mitochondrial integrity in organisms following exposure to pesticides. To achieve this, a high throughput method to assess pesticide effects on oxidative phosphorylation and mitochondria has been optimized for fish embryos. Fish embryos are first exposed to pesticides for 24 or 48 h, and oxygen consumption rates are measured using the Seahorse XFe24/96 Flux Analyzer (formerly Seahorse Biosciences, now Agilent). The assay utilizes a single embryo and precisely measures oxygen consumption and extracellular acidification. Based upon these measurements, characteristics related to mitochondrial bioenergetics are calculated to provide information on mitochondrial integrity. Using this approach, one can identify pesticides affecting the electron transport chain and ultimately ATP production. In this chapter, we describe the mitochondrial stress test to understand mitochondrial dysfunction and metabolic shifts within the fish embryo.

Effect of environmental level of methomyl on hatching, morphology, immunity and development related genes expression in zebrafish (Danio rerio) embryo

The extensive use of carbamate pesticides has led to a range of environmental and health problems, such as surface and groundwater contamination, and endocrine disorders in organisms. In this study, we focused on examining the effects of toxic exposure to the carbamate pesticide methomyl on the hatching, morphology, immunity and developmental gene expression levels in zebrafish embryos. Four concentrations of methomyl (0, 2, 20, and 200 μg/L) were administered to zebrafish embryos for a period of 96 h. The study found that exposure to methomyl accelerated the hatching process of zebrafish embryos, with the strongest effect recorded at the concentration of 2 μg/L. Methomyl exposure also trigged significantly reductions in heart rate and caused abnormalities in larvae morphology, and it also stimulated the synthesis and release of several inflammatory factors such as IL-1β, IL-6, TNF-α and INF-α, lowered the IgM contents, ultimately enhancing inflammatory response and interfering with immune function. All of these showed the significant effects on exposure time, concentration and their interaction (Time × Concentration). Furthermore, the body length of zebrafish exposed to methomyl for 96 h was significantly shorter, particularly at higher concentrations (200 μg/L). Methomyl also affected the expression levels of genes associated with development (down-regulated igf1, bmp2b, vasa, dazl and piwi genes), demonstrating strong developmental toxicity and disruption of the endocrine system, with the most observed at the concentration of 200 μg/L and 96 h exposure to methomyl. The results of this study provide valuable reference information on the potential damage of methomyl concentrations in the environment on fish embryo development, while also supplementing present research on the immunotoxicity of methomyl.

Bifenox compromises porcine trophectoderm and luminal epithelial cells in early pregnancy by arresting cell cycle progression and impairing mitochondrial and calcium homeostasis

Bifenox is a widely used herbicide that contains a diphenyl ether group. However its global usage, the cell physiological effects that induce toxicity have not been elucidated. In this study, the effect of bifenox was examined in porcine trophectoderm and uterine epithelial cells to investigate the potential toxicity of the implantation process. To uncover the toxic effects of bifenox, cell viability and apoptosis following treatment with bifenox were evaluated. To investigate the underlying cellular mechanisms, mitochondrial and calcium homeostasis were investigated in both cell lines. In addition, the dysregulation of cell signal transduction and transcriptional alterations were also demonstrated. Bifenox reduced cell viability and significantly increased the number of cells arrested at the sub-G1 stage. Moreover, bifenox depolarized the mitochondrial membrane and upregulated the calcium flux into the mitochondria in both cell lines. Cytosolic calcium flux increased in porcine trophectoderm (pTr) cells and decreased in porcine luminal epithelium (pLE) cells. In addition, bifenox activated the mitogen-activated protein kinase and phosphoinositide 3-kinase signaling pathways. Furthermore, bifenox inhibited the expression of retinoid receptor genes, such as RXRA, RXRB, and RXRG. Chemokine CCL8 was also downregulated at the mRNA level, whereas CCL5 expression remained unchanged. Overall, the results of this study suggest that bifenox deteriorates cell viability by arresting cell cycle progression, damaging mitochondria, and controlling calcium levels in pTr and pLE cells. The present study indicates the toxic potential of bifenox in the trophectoderm and luminal epithelial cells, which can lead to implantation disorders in early pregnancy.

Hapten synthesis and a colloidal gold immunochromatographic strip assay to detect nitrofen and bifenox in fruits

In this study, we synthesized two haptens similar in structure to nitrofen (NIT), and screened out five monoclonal antibodies with the ability to recognize NIT and bifenox (BIF) by competitive ELISA, with the lowest IC₅₀ values of 0.87 ng mL^-1 and 0.86 ng mL^-1, respectively. The antibody 5G7 was selected to be combined with colloidal gold to establish a lateral flow immunochromatographic assay strip. This method was shown to qualitatively and quantitatively detect the residues of NIT and BIF in fruit samples. The visual limits of detection for qualitative detection were 5 μg kg^-1 and 10 μg kg^-1 for NIT and BIF, respectively. The calculated limits of detection for quantitative detection were 0.75 μg kg^-1, 1.77 μg kg^-1 and 2.55 μg kg^-1 respectively, for nitrofen in orange, apple and grapes, and 3.54 μg kg^-1, 4.96 μg kg^-1 and 5.26 μg kg^-1, respectively, for bifenox. Thus the strip assay could be used for rapid analysis of fruit samples.

Screening potential toxicity of currently used herbicides in the freshwater amphipod Gammarus fossarum based on multi-level biomarker responses to field-realistic exposures

Herbicides are widely used to control weeds and maximize crop growth. Because of agricultural runoff, these chemicals are potentially hazardous to aquatic wildlife. However, their ecotoxicity and resulting disturbance in individual performance remain scarcely documented in freshwater crustaceans. This study aimed to screen the potential toxicity of currently used herbicides in the ecosystem engineer Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to 12 herbicides individually (quinmerac, mesotrione, bentazone, isoproturon, chlortoluron, metazachlor, chloridazone, diflufenican, flufenacet, aclonifen, prosulfocarb and metolachlor) at a field-realistic concentration (i.e. 10 μg/L). The sublethal effects were assessed by monitoring several biochemical, physiological and behavioural traits. In exposed gammarids, alterations in behavioural activities were observed, i.e. increased locomotion and respiration as a general trend. Moreover, biochemical biomarkers suggested herbicide-dependent disruptions in moulting, antioxidant responses and cell integrity. Integrating multi-metric variations through statistical analyses allowed us to identify herbicide clusters likely to trigger common sets of biological responses. Depressed antioxidant defence at the cell level and impaired respiration at the individual level were the predominant toxic effects of herbicides, related to their hydrophobic feature. Furthermore, establishing relationships between sublethal alterations in gammarids and acute lethality or chronic toxicity values defined for regulatory purposes supports the relevance of these alterations as early warnings of toxicity. Our findings demonstrate that currently used herbicides have unexpected toxicological effects in a non-target wild animal, with possible long-term alterations in population dynamics and associated ecological functions, which constitute promising diagnostic tools for risk assessment in agricultural areas.

Oxamyl exerts developmental toxic effects in zebrafish by disrupting the mitochondrial electron transport chain and modulating PI3K/Akt and p38 Mapk signaling

Oxamyl, a carbamate insecticide, is mainly used to control nematodes in the agricultural field. Although oxamyl is a widely used insecticide that is associated with ecological concerns, limited studies have examined the toxic effects of oxamyl on the developmental stage and the underlying mechanisms. In this study, the developmental toxicity of oxamyl was demonstrated using zebrafish, which is a representative model as it is associated with rapid embryogenesis and a toxic response similar to that of other vertebrates. The morphological alteration of zebrafish larvae was analyzed to confirm the sub-lethal toxicity of oxamyl. Analysis of transgenic zebrafish (olig2:dsRED and flk1:eGFP line) and mRNA levels of genes associated with individual organ development revealed that oxamyl exerted toxic effects on the development of neuron, notochord, and vascular system. Next, the adverse effect of oxamyl on the mitochondrial electron transport chain was examined. Treatment with oxamyl altered the PI3K/Akt signaling and p38 Mapk signaling pathways in zebrafish. Thus, this study elucidated the mechanisms underlying the developmental toxicity of oxamyl and provided information on the parameters to assess the developmental toxicity of other environmental contaminants.

Spectrofluorometric and computational approaches for the interaction studies of aclonifen and bifenox with human serum albumin

Interaction of two broadly used herbicides, aclonifen (ACF) and bifenox (BIF) with the major transporter in human circulation, human serum albumin (HSA) were examined using fluorescence and absorption spectral measurements combined with in silico analyses. Assessment of the fluorescence and absorption spectral results affirmed the complexation between ACF/BIF and HSA. Increase in the K_SV value with temperature characterized the ACF/BIF-induced quenching of the protein fluorescence as dynamic quenching. The moderate binding affinities (K_f = 1.74×10⁴ - 1.95×10⁶ M^-1 for ACF-HSA complex; K_f = 2.00×10³ - 1.02×10⁶ M^-1 for BIF-HSA complex) were pointed out between ACF/BIF and HSA, showing a relatively higher binding constant values with increasing temperatures. Quantitative evaluation of thermodynamic data (ΔS = +0.86 kJ mol^-1 K^-1 and ΔH = +225.43 kJ mol^-1 for ACF-HSA complex; ΔS = +1.11 kJ mol^-1 K^-1 and ΔH = +304.63 kJ mol^-1 for BIF-HSA complex) predicted the contribution of hydrophobic interactions in the ACF-HSA and BIF-HSA association processes, which were well supported by our molecular docking results. In silico analyses were made to acquire insight details into the ACF and BIF binding to HSA at the binding sites and suggested the locations of ACF and BIF binding sites as both subdomain IIA (site I) and subdomain IIIA (site II) of HSA, showing more preference toward site I.

Investigating the neurotoxicity of environmental pollutants using zebrafish as a model organism: A review and recommendations for future work

With the continuous development of precise detection technology, more and more pollutants have been detected in the environment. Among them, neurotoxic pollutants have attracted extensive attention due to their serious threat to vertebrates, invertebrates, and the whole ecosystem. Compared with other model organisms, zebrafish (Danio rerio) have become an important aquatic model to study the neurotoxicity of environmental pollutants because of their excellent molecular/physiological characteristics. At present, the research on the toxicity of environmental pollutants to the zebrafish nervous system focuses on morphology and behavior regulation, oxidative stress, gene expression, synthesis and release of neurotransmitters, and neuron development. However, studies on epigenetic toxicity, blood-brain barrier damage, and regulation of the brain-gut-microbiota axis still require further research at the molecular and signaling levels to clarify the toxic mechanisms of pollutants. This paper reviews the research on the toxic effects of pollutants in the environment (heavy metals and organic compounds) on the nervous system of zebrafish, summarizes and comments on the main research findings. The discussion of the problems, hot spots in the current research, and the prospects of the contents to be further studied are also included in this paper.

Occurrence, seasonal variations, and eco-risk of currently using organochlorine pesticides in surface seawater of the East China Sea and Western Pacific Ocean

We studied 19 targets currently using organochlorine pesticides (CUOCPs) from 98 samples in the Western Pacific Ocean and the East China Sea collected in 2019, 2020, and 2021. The samples were analyzed using a novel High-throat/High-volume Solid-Phase Extraction method. Eighteen individual CUOCPs were above the method detection limits. The levels of ∑₁₉CUOCPs ranged from 0.13 to 17.80 ng/L, with an average of 3.13 ± 14.67 ng/L. Dicofol was the main pollutant in the Western Pacific Ocean, while Pyridaben dominated the East China Sea. In the summer, land-source input was the primary source in the Western Pacific Ocean and the East China Sea. Historical residues were the main source in the East China Sea in spring. In the summer, the ecological risk assessment results indicated a relatively low risk to the Western Pacific Ocean and the East China Sea.

Aclonifen could induce implantation failure during early embryonic development through apoptosis of porcine trophectoderm and uterine luminal epithelial cells

Aclonifen is a diphenyl-ether herbicide that is used to control the growth of weeds while growing crops such as corn and wheat. Although the biochemical effects of aclonifen are well characterized, including its ability to inhibit protoporphyrinogen oxidase and carotenoid synthesis, the toxicity of aclonifen in embryonic implantation and development during early pregnancy, has not been reported. Thus, in this study, we investigated the potential interference of aclonifen in embryonic implantation using porcine trophectoderm (pTr) and uterine luminal epithelial (pLE) cells isolated during implantation period of early pregnancy. Cell viability in both pTr and pLE cells significantly decreased in a dose-dependent manner following aclonifen treatment. Moreover, the proportion of cells in the sub-G1 phase of the cell cycle gradually increased upon treatment with increasing concentrations of aclonifen, which in turn led to an increase in the number of apoptotic cells, as determined by annexin V and propidium iodide staining. Aclonifen treatment caused mitochondrial dysfunction by increasing the depolarization of the mitochondrial membrane potential and the mitochondrial calcium concentration. Aclonifen inhibited cell mobility by suppressing the expression of implantation-related genes in pTr and pLE cells. To explore the underlying mechanism, we evaluated the phosphorylation of PI3K and MAPK signaling molecules. The phosphorylation of AKT, S6, JNK, and ERK1/2 were significantly increased by aclonifen. Collectively, our results suggest that aclonifen may interrupt implantation during early pregnancy by disrupting maternal-fetal interaction.

Adverse effects of SYP-3343 on zebrafish development via ROS-mediated mitochondrial dysfunction

As a newly-invented and highly-efficiency strobilurin fungicide, pyraoxystrobin (SYP-3343) has been recognized as a highly poisonous toxin for a variety of aquatic organisms. Nevertheless, the developmental toxicity and potential mechanism of SYP-3343 have not been well-documented. The results showed that SYP-3343 was relatively stable and maintained within the range of 20 % in 24 h, and the LC₅₀ value to embryos at 72 hpf was 17.13 μg/L. The zebrafish embryotoxicity induced by 1, 2, 4, and 8 μg/L SYP-3343 is demonstrated by repressive embryo incubation, enhancive mortality rate, abnormal heart rate, malformed morphological characteristic, and impaired spontaneous coiling, indicating SYP-3343 mostly exerted its toxicity in a dose- and time-dependent manner. Besides SYP-3343 was critically involved in regulating cell cycle, mitochondrial membrane potential, and reactive oxygen species production as well as zebrafish primary cells apoptosis, which can be mitigated using antioxidant N-acetyl-L-cysteine. A significant change occurred in total protein content, the biochemical indices, and antioxidant capacities owing to SYP-3343 exposure. Additionally, SYP-3343 altered the mRNA levels of heart development-, mitochondrial function-, and apoptosis-related genes in zebrafish embryos. These results indicated that SYP-3343 induced apoptosis accompanying reactive oxygen species-initiated mitochondrial dysfunction in zebrafish embryos.

Ethalfluralin impairs implantation by aggravation of mitochondrial viability and function during early pregnancy

Ethalfluralin, a dinitroaniline-type herbicide, has been used for decades. As a result, its residues are detected on some farmlands. To determine the molecular mechanisms underlying the detrimental effects of ethalfluralin on early pregnancy, porcine luminal epithelium and trophectoderm cell lines were used. Ethalfluralin was found to inhibit the viability, proliferation, and migration of porcine luminal epithelial (pLE) and porcine trophectoderm (pTr) cells. Additionally, ethalfluralin induced apoptotic cell death by means of an imbalance in calcium homeostasis in both pLE and pTr cells. Ethalfluralin decreased mitochondrial membrane potential (ΔΨ_m) and impaired mitochondrial respiration by downregulating the mitochondrial respiratory complex-related genes. Ethalfluralin also activated endoplasmic reticulum stress signals and autophagy pathways, increased the phosphorylation of P38 MAPK and NF-κB, and suppressed the PI3K/AKT signaling pathway. Taken together, this study elucidated the molecular mechanisms by which ethalfluralin impedes the viability and mitochondrial function in fetal trophectoderm and maternal endometrial cells during early pregnancy.

Neuro-hepatopathological changes in juvenile Oreochromis niloticus exposed to sublethal concentrations of commercial herbicides

The current study estimates the impact of different common herbicides on antioxidant defenses and histological structure of liver and spinal cord of juvenile tilapia. Eighty-four fish were divided into seven groups: group 1 fish acted as controls and the remaining fish were exposed to sublethal concentrations of acetochlor, bispyribac-sodium, bentazon, bensulfuron-methyl, halosulfuron-methyl, or quinclorac at sublethal concentrations 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l, respectively, for 96 h. Antioxidant parameters changed in response to some test herbicides and the greatest effects were caused by exposure to acetochlor and quinelorac for all antioxidant measurements. Prominent histological changes in liver tissue included loss of liver architecture and the appearance of fatty liver cells, necrotic areas, foci of leukocytic infiltration and many apoptotic cells. The most obvious changes in the spinal cord in all treated fish were degradation of myelinated white matter fibers with the emergence of empty spaces, large aggregation of pyknotic neuroglial nuclei, and damaged areas in the dorsal horn of gray matter. Collectively, the harmful effect of tested herbicides on antioxidant capacity and significant alterations in histological structures of liver and spinal cord of Oreochromis niloticus.

Engineering single-atom catalysts toward biomedical applications

Due to inherent structural defects, common nanocatalysts always display limited catalytic activity and selectivity, making it practically difficult for them to replace natural enzymes in a broad scope of biologically important applications. By decreasing the size of the nanocatalysts, their catalytic activity and selectivity will be substantially improved. Guided by this concept, the advances of nanocatalysts now enter an era of atomic-level precise control. Single-atom catalysts (denoted as SACs), characterized by atomically dispersed active sites, strikingly show utmost atomic utilization, precisely located metal centers, unique metal-support interactions and identical coordination environments. Such advantages of SACs drastically boost the specific activity per metal atom, and thus provide great potential for achieving superior catalytic activity and selectivity to functionally mimic or even outperform natural enzymes of interest. Although the size of the catalysts does matter, it is not clear whether the guideline of "the smaller, the better" is still correct for developing catalysts at the single-atom scale. Thus, it is clearly a new, urgent issue to address before further extending SACs into biomedical applications, representing an important branch of nanomedicine. This review begins by providing an overview of recent advances of synthesis strategies of SACs, which serve as a basis for the discussion of emerging achievements in improving the enzyme-like catalytic properties at an atomic level. Then, we carefully compare the structures and functions of catalysts at various scales from nanoparticles, nanoclusters, and few-atom clusters to single atoms. Contrary to conventional wisdom, SACs are not the most catalytically active catalysts in specific reactions, especially those requiring multi-site auxiliary activities. After that, we highlight the unique roles of SACs toward biomedical applications. To appreciate these advances, the challenges and prospects in rapidly growing studies of SACs-related catalytic nanomedicine are also discussed in this review.

Aclonifen induces bovine mammary gland epithelial cell death by disrupting calcium homeostasis and inducing ROS production

Herbicides play key roles in agriculture. Aclonifen is a diphenyl ether herbicide that is widely used for sunflower, potato, corn, and wheat crops. Since it has a long half-life, it is considered persistent and can easily accumulate in the environment. Therefore, livestock and humans are at risk of exposure to aclonifen. Importantly, aclonifen is toxic to several mammals such as rats, mice, and dogs. However, the toxicity of aclonifen in cattle remains unclear. Therefore, we sought to investigate its toxicity in cattle using bovine mammary gland epithelial cells (MAC-T). We found that aclonifen induces sub-G1 phase arrest and represses MAC-T proliferation. In addition, aclonifen caused mitochondrial dysfunction, as evidenced by excessive ROS production and loss of mitochondrial membrane potential. Furthermore, cytosolic and mitochondrial calcium homeostases were disrupted after aclonifen treatment. Moreover, aclonifen treatment caused alterations in the PI3K/AKT and MAPK signaling pathways, which are involved in the regulation of cell survival and death. In conclusion, aclonifen causes MAC-T cell death through mitochondrial dysfunction and the collapse of calcium homeostasis.