Enhanced reproductive toxicity of photodegraded polylactic acid microplastics in zebrafish.

Microplastics are widely used due to their numerous advantages. However, they can have detrimental effects on marine ecosystems. When microplastics enter the ocean, they can be absorbed by marine organisms, leading to toxic effects. Additionally, the transformation of microplastics during natural degradation can alter their toxicity, necessitating further investigation. Polylactic acid (PLA) biodegradable plastics are commonly used, yet research on their toxicity, particularly their reproductive effects on aquatic organisms, remains limited. In this study, we conducted photodegradation of PLA using potassium persulfate as a catalyst to simulate natural degradation conditions. Our objective was to assess the reproductive toxicity of photodegraded PLA microplastics on zebrafish. The results revealed that photodegraded PLA exhibited elevated reproductive toxicity, resulting in abnormal oocyte differentiation, disruption of sexual hormone levels, and alterations in ovarian tissue metabolism. Metabolomics analysis indicated that both unphotodegraded PLA (UPLA) and photodegraded PLA (DPLA) disrupted oxidative stress homeostasis in zebrafish ovarian tissue by influencing pathways such as purine metabolism, phenylalanine metabolism, glutathione metabolism, and riboflavin metabolism. Furthermore, the DPLA treatment induced abnormal biosynthesis of taurocholic acid, which was not observed in the UPLA treatment group. Importantly, the DPLA treatment group exhibited more pronounced effects on offspring development compared to the UPLA treatment group, characterized by higher mortality rates, inhibition of embryo hatching, accelerated heart rates, and reduced larval body length. These findings underscore the varying levels of toxicity to zebrafish ovaries before and after PLA photodegradation, along with evidence of intergenerational toxicity.

Rapid, on-site quantitative determination of mycotoxins in grains using a multiple time-resolved fluorescent microsphere immunochromatographic test strip.

The label probe plays a crucial role in enhancing the sensitivity of lateral flow immunoassays. However, conventional fluorescent microspheres (FMs) have limitations due to their short fluorescence lifetime, susceptibility to background fluorescence interference, and inability to facilitate multi-component detection. In this study, carboxylate-modified Eu(III)-chelate-doped polystyrene nanobeads were employed as label probes to construct a multiple time-resolved fluorescent microsphere-based immunochromatographic test strip (TRFM-ICTS). This novel TRFM-ICTS facilitated rapid on-site quantitative detection of three mycotoxins in grains: Aflatoxin B1 (AFB1), Zearalenone (ZEN), and Deoxynivalenol (DON). The limit of detection (LOD) for AFB1, ZEN, and DON were found to be 0.03 ng/g, 0.11 ng/g, and 0.81 ng/g, respectively. Furthermore, the TRFM-ICTS demonstrated a wide detection range for AFB1 (0.05-8.1 ng/g), ZEN (0.125-25 ng/g), and DON (1.0-234 ng/g), while maintaining excellent selectivity. Notably, the test strip exhibited remarkable stability, retaining its detection capability even after storage at 4 °C for over one year. Importantly, the detection of these mycotoxins relied solely on simple manual operations, and with a portable reader, on-site detection could be accomplished within 20 min. This TRFM-ICTS presents a promising solution for sensitive on-site mycotoxin detection, suitable for practical application in various settings due to its sensitivity, accuracy, simplicity, and portability.

The combined toxic effects of polystyrene microplastics and different forms of arsenic on the zebrafish embryos (Danio rerio).

Microplastics have been widely studied for their ability to adsorb heavy metals. In the natural environment, arsenic exists in different forms and its toxicity depends mainly on its form and concentration. However, different forms of arsenic combined with microplastics have yet to be explored for their biological hazards. This study was conducted to reveal the adsorption mechanism of different forms of arsenic onto PSMP and to study the effects of PSMP on the tissue accumulation and developmental toxicity of different forms of arsenic in zebrafish larvae. As a result, the absorbing ability of PSMP for As(III) was 35 times higher than that of DMAs, in which hydrogen bonding plays an important role in the adsorption process. In addition, the adsorption kinetics of As(III) and DMAs on PSMP were in good agreement with the pseudo-second-order kinetic model. Furthermore, PSMP reduced the accumulation of As(III) early in zebrafish larvae development, thereby increasing hatching rates compared with the As(III)-treated group, whereas PSMP had no significant effect on DMAs accumulation in zebrafish larvae, but decreased hatching rates compared with the DMAs-treated group. In addition, except for the microplastic exposure group, the other treatment groups could lead to a decrease in the heart rate of zebrafish larvae. Both PSMP+As(III) and PSMP+DMAs exhibited aggravated oxidative stress compared with PSMP-treated group, but PSMP+As(III) caused more severe oxidative stress at later stages of zebrafish larvae development. Moreover, specific metabolic differences (e.g., AMP, IMP, and guanosine) were produced in the PSMP+As(III) exposure group, which would mainly affect purine metabolism and promoted specific metabolic disturbances. However, PSMP+DMAs exposure shared metabolic pathways altered by PSMP and DMAs, indicating an independent effect of these two chemicals. Taken together, our findings emphasized that the combined toxicity of PSMP and different forms of arsenic posed a health risk that cannot be ignored.