Effects of environmentally relevant concentrations of micro(nano)plastics on aquatic microorganisms:Changes in potential function but not in overall composition

Micro(nano)plastics(MNPs)are a growing problem as persistent environmental pollutants.Here,we investigated the impact of MNPs on microorganisms in aquatic microbial floc exposed to NPs(80 nm)and MPs(8μm)for 35 days.Water quality indicators were tested weekly and microbiological analyses were conducted on Day 7 and 28 after exposure.The results showed that there were significant differences in the levels of total ammonia nitrogen or nitrite between the MNPs groups and the control group,spanning from Day 7 to Day 28.For the microbial response,microbial community richness in the NPs and MPs groups were significantly increased at Day 7.Functional prediction showed that the relative abundances of bacteria associated with the“Forms Biofilms”,“Potentially Pathogenic”,“Plastic Degradation”and nitrogen cycle processes were significantly different after MNPs exposure.The results suggest that MNPs had no significant effect on the microbial diversity of mature microbial flocs.Findings suggest MPs could cause an increase in the relative abundance of potentially pathogenic bacteria,while NPs do not.In addition,stress associated with MNPs affected the nitrogen cycle of microorganisms,and NPs exerted greater impacts than MPs.Findings from this study further our understanding of the impact of MNPs at environmentally relevant concentrations on microorganisms in aquatic ecosystems.

The mevalonate pathway promotes the metastasis of osteosarcoma by regulating YAP 1 activity via RhoA

Osteosarcoma is the most common malignant bone tumour,and the metastasis of osteosarcoma is an important cause of death.Evidence has shown that the mevalonate pathway is highly activated and is expected to be a new target for tumour therapy.In this study,we investigated the effect of mevalonate signalling on osteosarcoma metastasis and its molecular mechanism.First,we found that the key rate-limiting enzyme of mevalonate signalling,3-hydroxy-3-methylglutaryl-CoA reductase(HMGCR),was highly expressed in osteosarcoma cells,and inhibition of HMGCR with simvastatin significantly inhibited the motility of 143B cells.Next,we found that YAP1 activity was significantly upregulated in osteosarcoma cells and that YAP1 knockdown inhibited the motility of 143B cells.We also found that the mevalonate pathway regulated the motility of 143B cells by modulating YAP1 phosphorylation and cellular localization.Moreover,we found that the activity of YAP1 was regulated by the mevalonate pathway by modulating the cell membrane localization of RhoA.Finally,we demonstrated that inhibition of the mevalonate pathway notably reduced the lung metastasis of 143B cells,as reflected by the decreased incidence and number of metastatic nodules and the increased survival time of the nude mice.Taken together,our findings suggest that the mevalonate pathway can promote the metastasis of osteosarcoma by activating YAP1 via RhoA.Inhibition of the mevalonate pathway may be a promising therapeutic strategy for osteosarcoma metastasis.