Projected harmful algal bloom frequency in the Yangtze River Estuary and adjacent waters.

Harmful algal blooms (HABs) are a frequent occurrence in China's offshore waters due to climate change and human activity, particularly in the Yangtze River Estuary and adjacent waters. Here, we studied HABs and their relationship with climatic and environmental factors in these waters from 1979 to 2016 using historical observations and reanalysis data. We then projected HABs frequency under various climate scenarios using the "environmental impact factor-frequency of HABs" mathematical model built using the BP neural network method and CIMP5 model data (RCP 2.6, RCP 4.5, and RCP 8.5). The results suggest a significant positive correlation between HABs frequency and seawater nutrient concentration, winter sea surface temperature, and low-wind days, and HABs frequency is anticipated to increase significantly by the 2040s compared with that of the historical era. Furthermore, future phytoplankton conditions are predicted to favor HAB species.

Protein arginine methyltransferase 8 regulates ferroptosis and macrophage polarization in spinal cord injury via glial cell-derived neurotrophic factor.

OBJECTIVE: To explore the influence of protein arginine methyltransferase 8 (PRMT8) regulating glial cell-derived neurotrophic factor (GDNF) on neuron ferroptosis and macrophage polarization in spinal cord injury (SCI). METHODS: A rat model of SCI was established through an injury induced by an external force. Basso, Beattie, and Bresnahan score, hematoxylin and eosin staining, and immunofluorescence were used, respectively, to detect changes in rat locomotion, spinal cord histopathology, and NeuN expression in the spinal cord. Iron content in the spinal cord and levels of malondialdehyde and glutathione were measured using detection kits. Transmission electron microscopy was used to reveal the morphological characteristics of mitochondria. Western blotting was performed to detect PRMT8, GDNF, cystine/glutamate transporter XCT, glutathione peroxidase 4, 4-hydroxynonenal, heme oxygenase-1, inducible nitric oxide synthase (iNOS), CD16, and arginase 1 (Arg1). The expression levels of iNOS and Arg1 in the spinal cord were visualized by immunofluorescence. ELISA was performed to measure the expression levels of IL-6, IL-1ß, and TNF-α. Rat dorsal root ganglion (DRG) neurons and RMa-bm rat macrophages were treated with lipopolysaccharide under hypoxic conditions. The viability and iron content of the neurons were detected using Cell Counting Kit-8 and a specific probe, respectively. Flow cytometry and immunofluorescence were used to assess macrophage polarization. Chromatin immunoprecipitation was used to identify the binding of PRMT8 to the GDFN promoter. RESULTS: Neuronal ferroptosis and M1 macrophage polarization were promoted, and PRMT8 expression was downregulated in SCI. PRMT8 overexpression exerted therapeutic effects on injured DRG neurons and RMa-bm cells. Moreover, PRMT8 overexpression inhibited ferroptosis and M1 macrophage polarization in rats with SCI. PRMT8 promoted GDNF expression by catalyzing H3K4 methylation. Knockdown of GDNF counteracted the therapeutic effects of PRMT8 overexpression. CONCLUSION: Overexpression of PRMT8 may inhibit ferroptosis and M1 macrophage polarization by increasing GDNF expression, thereby alleviating SCI.

Facilitative role of circPVT1 in osteogenic differentiation potentials of bone marrow mesenchymal stem cells from patients with osteoporosis through the miR-30d-5p/ITGB3 axis.

OBJECTIVE: The critical role of circular RNAs (circRNAs) in osteoporosis (OP) has been highlighted. We tried to explore the role of circPVT1 in OP in relation to microRNA-30d-5p (miR-30d-5p) and ITGB3. METHODS: After bone marrow collection, bone marrow mesenchymal stem cells (BMSCs) were isolated and identified. Then, Pearson coefficient was used to analyze the correlation among circPVT1, miR-30d-5p and ITGB3, and the binding sites were predicted and verified. Gain- and loss-of function assays in circPVT1, miR-30d-5p and ITGB3 were performed to analyze their effect on osteogenic differentiation of BMSCs. RESULTS: The osteogenic differentiation of BMSCs from OP patients was significantly decreased, and reduced circPVT1 expression was found in the BMSCs from OP patients. Overexpression of circPVT1 stimulated the formation of calcified nodules, increased alkaline phosphatase activity, and enhanced the expression of osteogenic marker genes in the BMSCs from OP patients. Additionally, circPVT1 expression was negatively correlated with miR-30d-5p, and miR-30d-5p was negatively correlated with ITGB3 in OP patients. Mechanically, circPVT1 regulated the osteogenic differentiation potential of BMSCs by relieving the inhibition of miR-30d-5p on ITGB3 through the competitive endogenous RNA mechanism. CONCLUSION: Our study highlighted a circPVT1/miR-30d-5p/ITGB3 axis in regulating osteogenic differentiation potential of BMSCs from OP patients.

Adaptive response of Dongzhaigang mangrove in China to future sea level rise.

Mangrove forests are valuable intertidal ecosystems that provide coastline protection, biodiversity maintenance, and carbon sequestration. However, their survival is under severe threat from rapidly rising sea levels. In this study, we aimed to investigate the changes in the area of the Dongzhaigang mangrove in China since the 1950s and causes of these changes using literature and remote sensing data. The impact of historical and future sea level rise (SLR) on the mangroves was analyzed using remote sensing data and climate model data under the low, intermediate, and very high greenhouse gas emission scenarios (Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5). The area of the mangrove forests decreased from 3416 to 1711 hm2 during 1956-1988 and remained constant at 1711 hm2 after the 1990s, owing to anthropogenic disturbances such as reclamation and aquaculture before the 1980s and the protection of nature reserve establishment after the 1990s, respectively. Under RCPs 4.5 and 8.5, SLR is expected to cause > 26% of the mangroves to disappear by 2100, whereas under RCP 2.6, only 17% of the mangroves will likely be lost. Biological measures such as reestablishment of ponds as mangrove forests, afforestation, and biological embankment for sediment trapping in coastal wetlands are recommended to enhance the resilience of mangroves to SLR.

High vulnerability and a big conservation gap: Mapping the vulnerability of coastal scleractinian corals in South China.

Scleractinian corals build the most complex and diverse ecosystems in the ocean with various ecosystem services, yet continue to be degraded by natural and anthropogenic stressors. Despite the rapid decline in scleractinian coral habitats in South China, they are among the least concerning in global coral vulnerability maps. This study developed a rapid assessment approach that combines vulnerability components and species distribution models to map coral vulnerability within a large region based on limited data. The approach contained three aspects including, exposure, habitat suitability, and coral-conservation-based adaptive capacity. The exposure assessment was based on seven indicators, and the habitat suitability was mapped using Maximum Entropy and Random Forest models. Vulnerability of scleractinian corals in South China was spatially evaluated using the approach developed here. The results showed that the average exposure of the study region was 0.62, indicating relatively high pressure. The highest exposure occurred from the east coast of the Leizhou Peninsula to the Pearl River Estuary. Aquaculture and shipping were the most common causes of exposure. Highly suitable habitats for scleractinian corals are concentrated between 18°N-22°N. Only 21.6 % of the potential coral habitats are included in marine protected areas, indicating that there may still be large conservation gaps for scleractinian corals in China. In total, 37.7 % of the potential coral habitats were highly vulnerable, with the highest vulnerability appearing in the Guangdong Province. This study presents the first attempt to map the vulnerability of scleractinian corals along the coast of South China. The proposed approach and findings provide an essential tool and information supporting the sustainable management and conservation of coral reef ecosystems, addressing an important gap on the world's coral reef vulnerability map.

Large-scale transport of PM2.5 in the lower troposphere during winter cold surges in China.

A comprehensive investigation using the air quality network and meteorological data of China in 2015 showed that PM2.5 driven by cold surges from the ground level could travel up to 2000 km from northern to southern China within two days. Air pollution is more severe and prominent during the winter in north China due to seasonal variations in energy usage, trade wind movements, and industrial emissions. In February 2015, two cold surges traveling from north China caused a temporary increase in the concentration of PM2.5 in Shanghai. Subsequently, the concentration of PM2.5 in Xiamen increased to a high of 80 µg/m3, which is double the average PM2.5 concentration in Xiamen during the winter. This finding is a new long-range transport mechanism comparing to the well-established mechanism, with long-range transport more likely to occur in the upper troposphere than at lower levels. These observations were validated by results from the back trajectory analysis and the RAMS- CMAQ model. While wind speed was found to be a major facilitator in transporting PM2.5 from Beijing to Xiamen, more investigation is required to understand the complex relationship between wind speed and PM2.5 and how it moderates air quality in Beijing, Shanghai, and Xiamen.