Rotenone encapsulated in pH-responsive alginate-based microspheres reduces toxicity to zebrafish

Toxic effects of the insecticide tolfenpyrad on zebrafish embryos: Cardiac toxicity and mitochondrial damage

Tolfenpyrad, a highly effective and broad-spectrum insecticide and acaricide extensively utilized in agriculture, presents a potential hazard to nontarget organisms. This study was designed to explore the toxic mechanisms of tolfenpyrad on zebrafish embryos. Between 24 and 96 h after exposure of the fertilized embryos to tolfenpyrad at concentrations ranging from 0.001 to 0.016 mg/L (96 h-LC50 = 0.017 mg/L), lethal effects were apparent, accompanied with notable anomalies including pericardial edema, increased pericardial area, diminished heart rate, and an elongated distance between the venous sinus and the arterial bulb. Tolfenpyrad elicited noteworthy alterations in the expression of genes pertinent to cardiac development and apoptosis, with the most pronounced changes observed in the cardiac development-related genes of bone morphogenetic protein 2b (bmp2b) and p53 upregulated modulator of apoptosis (puma). The findings underscore that tolfenpyrad induces severe cardiac toxicity and mitochondrial damage in zebrafish embryos. This data is imperative for a comprehensive assessment of tolfenpyrad risks to aquatic ecosystems, particularly considering the limited knowledge regarding its detrimental impact on aquatic vertebrates.

Preparation of pH-sensitive alginate-based hydrogel by microfluidic technology for intestinal targeting drug delivery

Hydrogel microspheres stand out in drug delivery due to their small particle size, biocompatibility and good internal stability. In this paper, pH-sensitive hydrogels are prepared by microfluidic technology for targeted drug delivery in the small intestine. A coaxial dual-channel microfluidic chip is constructed. By analyzing the effects of flow rates and three fracture stages (Rayleigh-Plateau instability crushing stage, pressure difference crushing stage and shear force crushing stage) on the size of hydrogel microspheres, the optimal control stage of the microsphere size is determined (shear force crushing stage). Based on this, the accurate control model of the hydrogel microsphere size is proposed. In addition, based on the coaxial dual channel microfluidic chip, a monolayer hydrogel microcapsule loaded with Indometacin is prepared. The core-shell hydrogel microcapsules loaded with Indometacin are prepared by an improved coaxial three channel microfluidic chip. The swelling rates of both microcapsules in simulated intestinal fluid are significantly higher than those in simulated gastric fluid. The results of in vitro simulated release experiments show that the two hydrogel microcapsules basically do not release in simulated gastric juice. In simulated intestinal fluid, single-layer hydrogel microcapsules show rapid release, while core-shell hydrogel microcapsules showed slow release. In conclusion, the alginate-based hydrogel microcapsules have good stability and pH sensitivity, and are suitable for targeted drug delivery in the small intestine.

Chitosan-based nanopesticides enhanced anti-fungal activity against strawberry anthracnose as "sugar-coated bombs"

A chitosan-based nanoparticle was prepared using chitosan (CS) and O-carboxymethyl chitosan (O-CMCS). Our study revealed that chitosan/O-carboxymethyl chitosan/tebuconazole nanoparticles (CS/O-CMCS/TBA NPs) exhibited superior antifungal activity, foliar adhesion, and microbial target adhesion performance compared to commercial suspension concentrate (SC). The antifungal activity of CS/O-CMCS/TBA NPs against C. gloeosporioides, with a 3.13-fold increase in efficacy over TBA (SC). We also found that low concentrations of CS/O-CMCS NPs promoted the growth of C. gloeosporioides and enhanced the fungal catabolism of chitosan. Overall, the CS/O-CMCS/TBA NPs were found to possess the remarkable capability to selectively aggregate around pathogenic microorganisms and CS/O-CMCS NPs can enhance the fungal catabolism of chitosan. CS/O-CMCS/TBA NPs, as a "sugar-coated bomb", was a promising asset for effective plant disease management and pesticide utilization through the affinity of chitosan-based nanoparticles and C. gloeosporioides, enabling targeted delivery and targeted release of their encapsulated active ingredient, which was important for the development and application of biocompatible chitosan-based nanopesticides.

Dopaminergic and serotoninergic neurotoxicity of lanthanide phosphate (TbPO4) in developing zebrafish

Rare earth elements (REEs) are exploited for global use in manufacturing. Such activities result in their release into the environment and the transformation into more stable phosphate deposition. The objective of this study was to evaluate molecular and behavioral changes of zebrafish exposed to the synthesized terbium phosphate (TbPO4) at concentrations of 10, 20, and 50 mg/L and to determine its potential for neurotoxicity. Metabolomics related to neurotransmitters, and assessment of transcripts and proteins were conducted to uncover the molecular mechanisms underlying TbPO4 with emphasis on neurotransmitter systems. Exposure to 20 mg/L TbPO4 induced larval hyperactivity and perturbed the cholinergic system in zebrafish. Based on metabolomics related to neurotransmitters, dopamine (DA), serotonin (5-HT), and many of their precursors and metabolites were decreased in abundance by TbPO4. In addition, the expression levels of transcripts related to the synthesis, transport, receptor binding, and metabolism of DA and 5-HT were analyzed at the mRNA and protein levels. Transcript and protein levels for tyrosine hydroxylase (TH), the rate-limiting enzyme for DA synthesis, were down-regulated in larval fish. Monoamine oxidase (MAO), an enzyme that catabolizes monoamines DA and 5-HT, was also reduced in mRNA abundance. We hypothesize that DA synthesis and monoamine metabolism are associated with behavioral alterations. This study elucidates putative mechanisms and exposure risks to wildlife and humans by characterizing phosphatic REE-induced neurotoxicity in developing zebrafish.

Assessment of cytisine as an insecticide candidate for Hyphantria cunea management: Toxicological, biochemical, and control potential insights

In the present study, the toxicological effects of cytisine on the H. cunea larvae were investigated, and the potential of cytisine as a botanical insecticide through field simulation experiments was evaluated. The results showed that cytisine treatment (0.25-2.5%) exerted significant biotoxic effects on the H. cunea larvae, including diminished weight, disruption of both positive (HcCKS1, HcPLK, HcCCNA) and negative (HcGADD and HcCDKN) regulatory genes associated with larval growth, increased mortality, and heightened oxidative damage (H2O2 and MDA). Cytisine treatment significantly reduced glucose content and inhibited the expression of key rate-limiting enzyme genes (HcPFK, HcPK, HcHK1, HcCS, and HcIDH2) within glycolysis and the tricarboxylic acid cycle pathways. Under cytisine treatment, detoxification enzyme activities (CarE and GST) and expression of detoxification genes (HcCarE1, HcCarE2, HcCarE3, HcGST1, and HcGST3) were inhibited in H. cunea larvae. An increased contents of SOD, CAT, ASA and T-AOC, as well as expression of antioxidant enzyme genes HcSOD1 and HcCAT2, was found in cytisine-treated H. cunea larvae. Simultaneously, this is accompanied by a significant reduction in the expression of four antioxidant enzyme genes (e.g., HcPOD1 and HcPOD2). In the field experiment, a cytisine aqueous solution (25 g/L) with pre-sprayed and directly sprayed ways demonstrated potent insecticidal activity against H. cunea larvae, achieving a mortality rate of 53.75% and 100% at 24 h, respectively. Taken together, cytisine has significantly weight inhibition and lethal toxicity on the H. cunea larvae, and can be developed as a botanical insecticide for H. cunea control.