Search

The illustration of the process of the PCBDA@AgNPs-MF for antibiofouling water disinfection. [Display omitted] Mature microfiltration (MF) membrane is a low-cost, effective, and promising technology to provide affordable purified water for people living in developing countries. However, the lack of disinfection ability and inherent membrane fouling problems have seriously restricted the large-scale application of conventional MF treatment system in producing safe drinking water. In this work, zwitterionic silver nanoparticles (AgNPs) with surface modification of poly(carboxybetaine acrylate- co -dopamine methacryamide) (PCBDA) copolymers were robustly immobilized onto commercial polyamide MF membrane via mussel-inspired chemistry for water disinfection. The designed microfiltration membrane, named as PCBDA@AgNPs-MF, exhibited integrated properties of high and stable payload of AgNPs, broad-spectrum anti-adhesive and antimicrobial activities, and easy removal of inactivated microbial cells from membrane surface. Ascribing to the synergetic effect of anti-adhesive and antimicrobial features brought by zwitterionic PCBDA@AgNPs, the biofilms growth on polyamide membrane surface was significantly inhibited, which showed potential access to achieve long-term biofouling resistance and maintain water flux for conventional MF membrane. As water disinfection device, these attributes enabled PCBDA@AgNPs-MF to effectively disinfect the model and natural bacteria-contaminated water. [ABSTRACT FROM AUTHOR]

Hexavalent chromium [Cr (VI)] is a common environmental pollutant. Although selenium (Se) can antagonize the toxicity of Cr (VI), the specific underlying mechanism has not been identified. To investigate this mechanism, we used potassium dichromate (K 2 Cr 2 O 7) and selenium-rich yeast (SeY) to construct single Cr (VI)- and combined Se/Cr (VI)-exposed broiler models during a 42-day period. Broilers were randomly assigned to the control (C), SeY (Se), SeY + Cr (VI) (Se/Cr), and Cr (VI) (Cr) groups. The antagonistic mechanisms of Se and Cr (VI) were evaluated using histopathological evaluation, serum and tissue biochemical tests, real-time fluorescence quantitative polymerase chain reaction, and western blotting. The results suggested that Se alleviated the morphological and structural damage to renal tubules and glomeruli, while reducing the organ index, creatinine levels, and blood urea nitrogen levels in the kidneys of Cr (VI)-exposed broilers. Furthermore, Cr (VI) reduced the levels of superoxide dismutase and glutathione, and increased the levels of malondialdehyde, in broiler kidney tissues. However, Se alleviated Cr (VI)-induced oxidative stress by increasing the levels of superoxide dismutase and glutathione, and decreasing the levels of malondialdehyde, within a certain range. Compared to the C group, the levels of p38, JNK, p-p38, p-JNK, p-p38/p38, and p-JNK/JNK significantly increased, whereas those of ERK, p-ERK, and p-ERK/ERK decreased, in the Cr group. Compared to the Cr group, the levels of p38, JNK, p-p38, p-JNK, p-p38/p38, and p-JNK/JNK significantly decreased, whereas those of ERK, p-ERK, and p-ERK/ERK increased, in the Se/Cr group. Furthermore, the levels of p53, c-Myc, Bax, Cyt-c, caspase-9, and caspase-3 significantly increased, and those of Bcl-2 and Bcl-2/Bax significantly decreased, following Cr (VI) exposure, while Se restored the expression of these genes. In conclusion, our findings suggest that SeY can protect against Cr (VI)-induced dysfunction and apoptosis by regulating the mitogen-activated protein kinase pathway activated by oxidative stress in broiler kidney tissues. [Display omitted] • Cr (VI) induces obvious toxicity in broiler kidney tissues. • SeY alleviates kidney dysfunction and oxidative stress caused by Cr (VI). • SeY regulates the MAPK pathway protecting broilers from Cr (VI)-induced apoptosis. [ABSTRACT FROM AUTHOR]