The size-dependence and reversibility of polystyrene nanoplastics-induced lipid accumulation in mice: Possible roles of lysosomes.

Nanoplastics (NPs) continue to accumulate in global aquatic and terrestrial systems, posing a potential threat to human health through the food chain and/or other pathways. Both in vivo and in vitro studies have confirmed that the liver is one of the main organs targeted for the accumulation of NPs in living organisms. However, whether exposure to NPs induces size-dependent disorders of liver lipid metabolism remains controversial, and the reversibility of NPs-induced hepatotoxicity is largely unknown. In this study, the effects of long-term exposure to environmentally relevant doses of polystyrene nanoplastics (PS-NPs) on lipid accumulation were investigated in terms of autophagy and lysosomal mechanisms. The findings indicated that hepatic lipid accumulation was more pronounced in mice exposed to 100 nm PS-NPs compared to 500 nm PS-NPs. This effect was effectively alleviated after 50 days of self-recovery for 100 nm and 500 nm PS-NPs exposure. Mechanistically, although PS-NPs exposure activated autophagosome formation through ERK (mitogen-activated protein kinase 1)/mTOR (mechanistic target of rapamycin kinase) signaling pathway, the inhibition of Rab7 (RAB7, member RAS oncogene family), CTSB (cathepsin B), and CTSD (cathepsin D) expression impaired lysosomal function, thereby blocking autophagic flux and contributing to hepatic lipid accumulation. After termination of PS-NPs exposure, lysosomal exocytosis was responsible for the clearance of PS-NPs accumulated in lysosomes. Furthermore, impaired lysosomal function and autophagic flux inhibition were effectively alleviated. This might be the main reason for the alleviation of PS-NPs-induced lipid accumulation after recovery. Collectively, we demonstrate for the first time that lysosomes play a dual role in the persistence and reversibility of hepatotoxicity induced by environmental relevant doses of NPs, which provide novel evidence for the prevention and intervention of liver injury associated with nanoplastics exposure.

Epstein-Barr virus is a promoter of lymphoma cell metastasis.

It is well-known that Epstein-Barr virus (EBV) is the promoter of cell tumourigenesis. We found that EBV is also a promoter of lymphoma cell dissemination, because we found the typical morphopathological phenomenon of cell adhesion, which confirmed that the adhesion of tumour cells was higher than that of normal cells. We also observed that tumour cells disrupted the dynamic pathological changes of vascular endothelial cells, and this made it clear that the rate of tumour cell metastasis was directly proportional to the degree of EBV infection. Furthermore, when we discovered exosomes, it was considered that this was associated with cancer stem cells, suggesting the formation of a microenvironment before tumour cell metastasis. In addition, competitive inhibition was found in cell adhesion, indicating the breakthrough point of preventing tumour cell metastasis, which has clinical reference value for tumour immunotherapy.

Selenium nanovirus and its cytotoxicity in selenite-exposed higher living organisms.

Selenium (Se) is an essential micronutrient in living organisms, having a narrow margin between essential and potentially toxic intake/exposure. Thus, the biochemistry of Se in living organisms must be studied in-depth to determine the underlying mechanism of Se cytotoxicity. In this study, we report the emergence of selenium nanovirus (SeNVs) in selenite-exposed fish (freshwater and saltwater) and plants (dryland) and its toxicity in them. SeNVs were found in both the abdomen and tail of Oryzias melastigma and saltwater Rhodeus ocellatus, which led to their death. The occurrence of the intracellular assembly of SeNVs was observed in the roots and leaves of corn Zea mays, but not in those of Limnobium laevigatum. SeNVs led to the death of Z. mays but caused chronic toxicity in L. laevigatum. SeNVs should be a system or structure that dissipates the intracellular redox gradients of the host cells, with simple information consisting Se-O, Se-N, or Se-S bond, that would ensure elemental Se ligand binding with nearly specific biomolecules in host cells, thereby maintaining their composition and stabilizing their structure. The multiple toxic effects of Se, therefore, could be the consequence of increase of entropy in the host cells caused by the intracellular assembly of SeNVs. This study may provide an insight into the underlying mechanism of Se in environmental toxicology and its applications in human health.

[Characteristics of Antibiotic Resistance Genes in Downstream Areas of the Aojiang River, Fujian Province].

Many cities are located in the downstream areas of rivers. Rapid urbanization may result in drastic changes in the urban river ecosystem. Antibiotic resistant genes (ARGs) are considered to be emerging environmental pollutants, which may do harm to the health of humans and may pose a potential risk for urban ecological safety by the dissemination and enrichment of ARGs in urban rivers. In this study, a high-throughput quantitative PCR technique was used to investigate the diversity and abundance of ARGs at three sites in Lianjiang County and the estuary of the Aojiang River, Fujian Province. The results show the abundance of ARGs in the downstream urban area of Lianjiang County (3.9×1010 copies·L-1) is significantly higher than upstream of the urban area and the estuary of the Aojiang River. A total of 129 ARGs are detected in the downstream urban area, which is higher than in the upstream and the estuary. The results also suggest that ARGs are persistent and not easy to reduce in the natural river following the occurrence of ARGs and indicated that the urban river is an important reservoir of ARGs.

[Distribution Characteristics of Antibiotic Resistance Genes in Sika Deer Farm].

Sika deer breeding is rapidly developing in South China during the recent years; however, the impact of sika deer breeding on the abundance and diversity of antibiotic resistance genes (ARGs) in sika deer farm remains elusive. In this study, profiles of ARGs were investigated using high-throughput qPCR technique. The results showed that the abundance of ARGs varied among different samples in the following order, deer manure composting > deer manure > vegetable soil > pristine soil, and the profiles of ARGs in these samples were significantly different (P<0.05). The abundance of ARGs was significantly correlated to that of mobile genetic elements (MGEs), implicating the potential of horizontal transfer of ARGs, which might accelerate the dissemination and enrichment of ARGs in the environment of sika deer farm.