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.

Resmethrin disrupts mitochondria-associated membranes and activates endoplasmic reticulum stress, leading to proliferation inhibition in cultured mouse Leydig and Sertoli cells.

Resmethrin, a pyrethroid pesticide used to control insects, is toxic to non-target organisms and other mammals. However, little is known about the reproductive toxicity of resmethrin in the testes, or its mechanism of toxicity. In this study, we investigated the testicular toxicity of resmethrin on mouse Leydig (TM3) and Sertoli (TM4) cells, focusing on the mitochondria and endoplasmic reticulum (ER). We found that resmethrin inhibited proliferation and cell cycle progression and disrupted mitochondrial membrane potential (MMP; ΔΨ) in TM3 and TM4 cells. In particular, resmethrin exposure significantly reduced the expression of mitochondria-associated membranes (MAMs) proteins, such as Vapb, Vdac, and Grp75, in both cell lines. Resmethrin also disrupts calcium homeostasis in the mitochondrial matrix and cytoplasm. In addition, resmethrin activates oxidative stress-mediated ER stress signals. Finally, we confirmed that 4-PBA, an ER stress inhibitor, restored the growth of TM3 and TM4 cells, which was decreased by resmethrin. Therefore, we confirmed that resmethrin hampered MAMs and activated ER stress, thus suppressing TM3 and TM4 cell proliferation.

Terbutryn causes developmental toxicity in zebrafish (Danio rerio) via apoptosis and major organ malformation in the early stages of embryogenesis.

Terbutryn (2-(ethylamino)-4-(tert-butylamino)-6-(methylthio)-1,3,5-triazine) is a substituted symmetrical triazine herbicide used in agricultural fields to prevent undesired vegetation growth by inhibiting photosynthesis in target weeds. Although terbutryn has various benefits, long-term exposure, misuse, or abuse of terbutryn may cause non-target toxicity and severe ecosystem pollution. To provide a detailed description of the embryonic developmental toxicity of terbutryn, zebrafish (Danio rerio) were exposed to 2, 4, and 6 mg/L of terbutryn and the morphological changes, pathological abnormalities, and developmental endpoints were assessed relative to that of a solvent control. The results showed that terbutryn induces a loss of survivability, reduction in body and eye size, and edema in the yolk sac. Through fluorescence microscopy, blood vessels, motor neurons, and liver development were investigated using transgenic zebrafish models based on fluorescently tagged genes (fllk1:eGFP, olig2:dsRed, and L-fabp:dsRed). Furthermore, cell death by apoptosis in zebrafish caused by terbutryn exposure was evaluated via acridine orange staining, which is a selective fluorescent staining agent. To support the preceding results, gene expression alterations caused by terbutryn exposure in zebrafish larvae were assessed. The overall results indicate that exposure to terbutryn induces apoptosis and disrupts organ development. These embryonic developmental toxicity results suggest that terbutryn should be applied in the right areas at the appropriate rates, concentrations, and quantities.

Developmental toxicity of prometryn induces mitochondrial dysfunction, oxidative stress, and failure of organogenesis in zebrafish (Danio rerio).

Prometryn, 2-methylthio-4,6-bis(isopropylamino)-1,3,5-triazine, is a selective thiomethyl triazine herbicide widely used to control unwanted weeds and harmful insects by inhibiting electron transport in target organisms. Despite having various advantages, herbicides pose as a major threat to the environment and human health due to persistent contamination, bioaccumulation, and damage to non-target organisms. In this study, the developmental toxicity of 5, 10, and 20 mg/L prometryn in zebrafish (Danio rerio) embryos was evaluated and compared to that of the solvent control for 96 h. Several transgenic zebrafish models (fli1a:eGFP, flk1:eGFP, olig2:dsRed and L-fabp:dsRed) were visually assessed to detect fluorescently tagged genes. Results showed that prometryn shortened body length, and induced yolk sac, heart edema, abnormal heart rate, and loss of viability. Fluorescence microscopy revealed that prometryn exposure caused defects in organ development, reactive oxygen species accumulation, and apoptotic cell death. Mitochondrial bioenergetics were also evaluated to determine the effect of prometryn on the electron transport chain activity and metabolic alterations. Prometryn was found to interfere with mitochondrial function, ultimately inhibiting energy metabolism and embryonic development. Collectively, our findings suggest that prometryn is a potential contaminate for non-target sites and organisms, especially aquatic, and emphasize the need to consider the toxic effects of prometryn.

Identification of enteroviruses by using monoclonal antibodies against a putative common epitope.

A common epitope region of enteroviruses was identified by sequence-independent single-primer amplification (SISPA), followed by immunoscreening of 11 cDNA libraries from two Korean enterovirus isolates (echoviruses 7 and 30) and a coxsackievirus B3 (ATCC-VR 30). The putative common epitope region was localized in the N terminus of VP1 when the displayed recombinant proteins from the phages were chased by the convalescent-phase sera. The genomic region encoding the common epitope region was amplified and then expressed by using the vector pGEX-5X-1. The antigenicity of the expressed recombinant protein was identified by Western blotting with guinea pig antisera for six different serotypes of enteroviruses. After successive immunization of mice with the recombinant common epitope protein, splenocytes were extracted and hybridized with P3X63-Ag8-653 cells. A total of 24 hybridomas that produced monoclonal antibodies (MAbs) against the putative common epitope of enteroviruses were selected. Four of these were immunoglobulin G1 isotypes with a kappa light chain. These MAbs recognized 15 Korean endemic serotypes and prototypes of enteroviruses in an indirect immunofluorescence assay. These results suggest that the expressed protein might be a useful antigen for producing group common antibodies and that the use of the MAbs against the putative common epitope of enteroviruses might be a valuable diagnostic tool for rapidly identifying a broad range of enteroviruses.