Micro-algal astaxanthin ameliorates polystyrene microplastics-triggered necroptosis and inflammation by mediating mitochondrial Ca2+ homeostasis in carp's head kidney lymphocytes (Cyprinus carpio L.).

Polystyrene microplastics (PM) is a pressing global environmental concern, posing substantial risks to aquatic ecosystems. Microalgal astaxanthin (MA), a heme pigment, safeguards cells against oxidative damage induced by free radicals, which contributes to various health conditions, including aging, inflammation and chronic diseases. Herein, we investigated the potential of MA in ameliorating the immunotoxicity of PM on carp (Cyprinus carpio L.) based on head kidney lymphocytes treated with PM (250 µM) and/or MA (100 µM). Firstly, CCK8 results showed that PM resulted in excessive death of head kidney lymphocytes. Secondly, head kidney lymphocytes treated with PM had a higher proportion of necroptosis, and the levels of necroptosis-related genes in head kidney lymphocytes were increased. Thirdly, the relative red fluorescence intensity of JC-1 and MitoSox showed decreased mitochondrial membrane potential and increased mtROS in head kidney lymphocytes treated with PM. MitoTracker® Green FM fluorescence analysis revealed enhanced mitochondrial Ca2+ levels in PM-treated lymphocytes, corroborating the association between PM exposure and elevated intracellular Ca2+ dynamics. PM exposure resulted in upregulation of calcium homeostasis-related gene (Orail, CAMKIIδ and SLC8A1) in lymphocytes. Subsequent investigations revealed that PM exposure reduced miR-25-5p expression while increasing levels of MCU, MICU1, and MCUR1. Notably, these effects were counteracted by treatment with MA. Furthermore, PM led to the elevated secretion of inflammatory factors (IFN-γ, IL-1ß, IL-2 and TNF-α), thereby inducing immune dysfunction in head kidney lymphocytes. Encouragingly, MA treatment effectively mitigated the immunotoxic effects induced by PM, demonstrating its potential in ameliorating necroptosis, mitochondrial dysfunction and immune impairment via regulating the miR-25-5p/MCU axis in lymphocytes. This study sheds light on safeguarding farmed fish against agrobiological threats posed by PM, highlighting the valuable applications of MA in aquaculture.

Self-assembly of eugenol-loaded particles to regulate the adhesion of carriers on leaves for efficient foliar applications and ecotoxicological safety.

Currently, there is a pressing need to develop an agrochemical-loaded system that is both uncomplicated and efficient, thereby enhancing the adhesion of agrochemical to leaf surfaces and optimizing their insecticidal efficacy, while concurrently mitigating environmental risks. The flexible eugenol-loaded particles were synthesized via a one-step polyurethane self-assembly reaction, utilizing polyethylene glycol (PEG) as the soft segment and 4,4-diphenylmethane diisocyanate (MDI) as the hard segment. The increase in the length of the soft segment enhances the flexibility of the particles, thereby improving the contact area and adhesion with the foliar surface. When flexible particles are applied on the foliar surface, they can achieve satisfactory resistance to rainfall erosion. When the PEG molecular weight is 800, the residual concentration of eugenol can still reach 42.11% after 6 washes. The carrier protects the active ingredients and improves the resistance to ultraviolet irradiation. After 5 h of ultraviolet irradiation, the concentration of eugenol remained at 59.03% when PEG with a molecular weight of 200 was employed. Greenhouse experiments showed that the flexible transformation of particles greatly enhanced the application effect of spray on the foliar surface of particles. After undergoing three washes, the mortality of the particles can be enhanced by 5.4-8.4 times compared to that of emulsion concentrate (EC) sample. The enhancement of leaf retention performance reduces environmental risks caused by pesticide loss. Meanwhile, the controlled release of particles also reduces the acute toxicity to zebrafish. The toxicity selection pressure of the EUG@P800-Ps sample is 10.6 times that of the EC sample. In conclusion, the preparation process of the system is simple, and the flexible transformation is an effective strategy to improve the foliar application effect of spray and improve the environmental safety.

Lignin microcapsules prepared on the basis of flexible skeleton with high foliar retention and UV shielding properties.

Lignin-based microcapsules are extremely attractive for their biodegradability and photolysis resistance. However, the water-soluble all-lignin shells were unsatisfactory in terms of rainfall and foliar retention, and lacked the test of agricultural production practices. Herein, a novel microcapsule based on a flexible skeleton formed by interfacial polymerization and absorbed with lignin particles (LPMCs) was prepared in this study. Further analysis demonstrated that the shell was formed by cross-linking the two materials in layers and showed excellent flexibility and photolysis resistance. The pesticide loaded LPMCs showed about 98.68 % and 73.00 % improvement in scour resistance and photolysis resistance, respectively, as compared to the bare active ingredient. The foliar retention performance of LPMCs was tested in peanut plantations during the rainy season. LPMCs loaded with pyraclostrobin (Pyr) and tebuconazole (Teb) exhibited the best foliar disease control and optimum plant architecture, resulting in an increase in yield of about 5.36 %. LPMCs have a promising application prospect in the efficient pesticide utilization, by controlling its deformation, adhesion and release, an effective strategy for controlling diseases and managing plant growth was developed.