Water quality assessment in a large plateau lake in China from 2014 to 2021 with machine learning models: Implications for future water quality management.

Amid the global surge of eutrophication in lakes, investigating and analyzing water quality and trends of lakes becomes imperative for formulating effective lake management policies. Water quality index (WQI) is one of the most used tools to assess water quality by integrating data from multiple water quality parameters. In this study, we analyzed the spatio-temporal variations of 11 water quality parameters in one of the largest plateau lakes, Erhai Lake, based on surveys from January 2014 to December 2021. Leveraging machine learning models, we gauged the relative importance of different water quality parameters to the WQI and further utilized stepwise multiple linear regression to derive an optimal minimal water quality index (WQImin) that required the minimal number of water quality parameters without compromising the performance. Our results indicated that the water quality of Erhai Lake typically showed a trend towards improvement, as indicated by the positive Mann-Kendall test for WQI performance (Z = 2.89, p < 0.01). Among the five machine learning models, XGBoost emerged as the best performer (coefficient of determination R2 = 0.822, mean squared error = 3.430, and mean absolute error = 1.460). Among the 11 water quality parameters, only four (i.e., dissolved oxygen, ammonia nitrogen, total phosphorus, and total nitrogen) were needed for the optimal WQImin. The establishment of the WQImin helps reduce cost in future water quality monitoring in Erhai Lake, which may also serve as a valuable framework for efficient water quality monitoring in similar waters. In addition, the elucidation of spatio-temporal patterns and trends of Erhai Lake's water quality serves as a compass for authorities, offering insights to bolster lake management strategies in the future.

Habitual feeding patterns impact polystyrene microplastic abundance and potential toxicity in edible benthic mollusks.

That increasing microplastics (MPs, <5 mm) eventually end up in the sediment which may become a growing menace to diverse benthic lives is worthy of attention. In this experiment, three edible mollusks including one deposit-feeding gastropod (Bullacta exarate) and two filter-feeding bivalves (Cyclina sinensis and Mactra veneriformis) were exposed to polystyrene microplastic (PS-MP) for 7 days and depurated for 3 days. PS-MP numbers in the digestive system and non-digestive system, digestive enzymes, oxidative stress indexes, and a neurotoxicity index of three mollusks were determined at day 0, 3, 7, 8 and 10. After seven-day exposure, the PS-MP were found in all three mollusks' digestive and non-digestive systems. And PS-MP in M. veneriformis (9.57 ± 2.19 items/individual) was significantly higher than those in C. sinensis (3.00 ± 2.16 items/individual) and B. exarate (0.83 ± 1.07 items/individual) at day 7. Three-day depuration could remove most of the PS-MP in the mollusks, and higher PS-MP clearance rates were found in filter-feeding C. sinensis (77.78 %) and M. veneriformis (82.59 %) compared to surface deposit-feeding B. exarate (50.00 %). The digestive enzymes of B. exarate significantly reacted to PS-MP exposure, while oxidative responses were found in C. sinensis. After three-day depuration, the changes of digestive enzymes and the oxidative states were fixed, but neurotoxicity induced by PS-MP was not recoverable. Besides, it is noteworthy that changes of digestive enzymes and acetylcholinesterase are related to feeding patterns.

Understanding the patterns and processes underlying water quality and pollution risk in West-Africa River using self-organizing maps and multivariate analyses.

Rivers are dynamic systems in complex interactions with their surrounding environments. Reliable and fast interpretation of water quality is therefore needed for sustainable river management. Unfortunately, water quality and environmental status interactions have not yet been documented sufficiently in West-Africa. This study explored the spatial-latitudinal and seasonal features of water quality along the Sô River Basin (SRB, West Africa) using self-organizing map (SOM) and principal component analysis. Twenty-two water quality variables were measured in the surface layer at 12 different sampling sites during a twenty-four-month period from July 2016 to June 2018. The results revealed three water quality groups, following an upstream-downstream pollution gradient: (1) upstream and middle reach sites with high dissolved oxygen and Secchi disk depth values, which are more suitable for the aquatic biota; (2) downstream sites with high concentrations of ammonium, biochemical oxygen demand, and heavy metals especially in flood period, reflecting both high organic and heavy metal pollution; and (3) brackish downstream sites characterized by less heavy metal and organic pollutions. No significant variation was observed between seasons. However, the SRB relatively suffered from higher risks of heavy metal contamination and organic pollution in wet seasons. Although hydroclimatic processes affect the water quality, anthropogenic inputs of point and non-point sources were identified and discussed as a more prominent factor contributing to variation in the water quality condition. These results offer insights into the water quality dynamics in river-estuary system as well as potential pollution sources, crucial for defining sanitation, and management measures.

Effects of recombinant human growth hormone on proliferation and differentiation of cementoblast and ERK1 / 2, JNK / SAPK and p38MAPK signaling pathway.

To investigate the effects of recombinant human growth hormone on the proliferation and differentiation of cementoblast and the signal pathways of ERK1 / 2, JNK / SAPK and p38MAPK, osteoblasts (OCCM-30) were cultured in vitro. The OCCM-30 was treated with different concentrations of recombinant human growth hormone (rhGH) (0, 10, 50 ng/mL) for 1 d and 2 d, respectively. MTT assay was used to test the proliferation of OCCM-30 cells by rhGH. The effect of BSP, OPN, OCN and ALP genes was detected by RT-PCR after one day. The activity of alkaline phosphatase (ALP) was detected after treatment with OCCM-30 for five days at different concentrations of rhGH. After treatment with OCCM-30 at 100 ng/mL rhGH for 0 min, 5 min, 10 min, 15 min, 30 min and 60 min, the phosphorylation levels of ERK1/2, JNK/SAPK and p38MAPK were detected by Western blot. Results showed that rhGH could promote the proliferation of OCCM-30 cells, and the proliferation of OCCM-30 cells increases with the increase of rhGH concentration. After one day of culture, the levels of the BSP and ALP genes increased with the increase of rhGH concentration (P<0.05); the OPN gene level in the 10 ng/mL group was significantly higher than that in the blank group, and the 50 ng/mL group was significantly lower than the blank group. (P<0.05); OCN gene levels in the 10 ng/mL group and 50 ng/mL group were not significantly different from those in the blank group (P>0.05). Compared with the blank group, the ERK 1/2 phosphorylation level increased at 5 min in the 100 ng/mL group, reached the maximum at 10 min, decreased significantly at 15 min, decreased to the original level at 30 min, and had no significant change in ERK 1/2 total protein level; 100 ng/mL rhGH had no significant effect on SAPK/JNK, p38MAPK phosphorylation and total protein levels in OCCM-30 cells (P>0.05). It was concluded that 10ng/mL and 50ng/mL rhGH could promote the proliferation of OCCM-30 cells and promote the expression of the BSP gene and ALP gene. Low-dose rhGH is beneficial to OPN gene expression, and high-dose rhGH inhibits OPN gene expression. 100 ng/mL rhGH promoted the ERK 1/2 pathway and had no effect on the SAPK/JNK and p38 MAPK pathways.

Predicting the abundance of metal resistance genes in subtropical estuaries using amplicon sequencing and machine learning.

Heavy metals are a group of anthropogenic contaminants in estuary ecosystems. Bacteria in estuaries counteract the highly concentrated metal toxicity through metal resistance genes (MRGs). Presently, metagenomic technology is popularly used to study MRGs. However, an easier and less expensive method of acquiring MRG information is needed to deepen our understanding of the fate of MRGs. Thus, this study explores the feasibility of using a machine learning approach-namely, random forests (RF)-to predict MRG abundance based on the 16S rRNA amplicon sequenced datasets from subtropical estuaries in China. Our results showed that the total MRG abundance could be predicted by RF models using bacterial composition at different taxonomic levels. Among them, the relative abundance of bacterial phyla had the highest predicted accuracy (71.7 %). In addition, the RF models constructed by bacterial phyla predicted the abundance of six MRG types and nine MRG subtypes with substantial accuracy (R2 > 0.600). Five bacterial phyla (Firmicutes, Bacteroidetes, Patescibacteria, Armatimonadetes, and Nitrospirae) substantially determined the variations in MRG abundance. Our findings prove that RF models can predict MRG abundance in South China estuaries during the wet season by using the bacterial composition obtained by 16S rRNA amplicon sequencing.

Inhibition of ER stress-activated JNK pathway attenuates TNF-α-induced inflammatory response in bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMMSCs) are characterized by their pluripotent differentiation and self-renewal capability and have been widely applied in regenerative medicine, gene therapy, and tissue repair. However, inflammatory response after BMMSCs transplantation was found to impair the osteogenic differentiation of BMMSCs. Thus, understanding the mechanisms underlying inflammation response will benefit the clinical use of BMMSCs. In this study, using a cell model of TNF-α-induced inflammatory response, we found that TNF-α treatment greatly elevated intracellular oxidative stress and induced endoplasmic reticulum (ER) stress by elevating the expression levels of ER sensors, such as PERK, ATF6 and IRE1A. Oxidative stress and ER stress formed a feedback loop to mediate TNF-α-induced inflammation response in BMMSCs. Moreover, c-Jun N-terminal kinase (JNK) signal pathway that coupled to the ER stress was significantly activated by increasing its phosphorylation upon TNF-α treatment. Importantly, pharmacological inhibition of ER stress effectively eliminated the phosphorylation of JNK and attenuated the TNF-α-induced inflammation response. In conclusion, our results indicated that TNF-α induced oxidative and ER stress, thereby leading to JNK activation, and generating inflammation response in BMMSCs. This pathway underlying TNF-α-induced inflammation response may provide new strategies to improve BMMSCs osteogenesis and other inflammation-associated bone diseases.

Intracellular Ca2+ signaling mediates IGF-1-induced osteogenic differentiation in bone marrow mesenchymal stem cells.

Insulin-like growth factor 1 (IGF-1), a multifunctional peptide that involves in cell proliferation and differentiation, can induce strong osteogenic differentiation in bone marrow mesenchymal stem cells (BMMSCs). However, it remains unknown whether intracellular Ca2+ signal contributes to the IGF-1-induced osteogenic differentiation of BMMSCs. In this study, we attempted to investigate the effect of IGF-1 on the gene expression of intracellular Ca2+-handling proteins and figure out whether the intracellular Ca2+ signal affects IGF-1-induced osteogenic differentiation. We found that IGF-1 treatment significantly increased cell proliferation and induced cell morphological changes with an increase of cell surface area. Quantitative PCR and Western blot analysis showed that osteoblast marker proteins, including alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) were significantly upregulated by IGF-1 treatment, indicating IGF-1 induced osteogenic differentiation in BMMSCs. Interestingly, the expression levels of the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) 3 and inositol-1,4,5-triphosphate receptor (IP3R) 2 were dramatically elevated during the IGF-1-induced osteogenic differentiation. Consistently, IGF-1-treated cells exhibited greater Ca2+ response to ATP. Importantly, blocking SERCA by thapsigargin markedly impaired IGF-1-induced osteogenic differentiation, indicating that intracellular Ca2+ mediated IGF-1-induced osteogenic differentiation in BMMSCs, probably via Akt signal pathway, which may provide new insight for the treatment of osteoporosis.

Patterns of fish communities and water quality in impounded lakes of China's south-to-north water diversion project.

Understanding the ecological impacts of large-scale hydraulic projects is critical for maintaining ecosystem health while meeting human water needs. It is, however, currently hindered by a lack of direct evidence on ecological impacts associated with this type of project particularly on water quality and fish communities. Here, we characterized patterns and variations of fish communities and water quality in five impounded lakes of the Chinese South-to-North Water Diversion Project (SNWDP), with the aim of better understanding potential ecological impacts of inter-basin water transfers. We found that 1) the impacts of water transfer on water quality in the impounded lakes was generally characterized by hydrological parameters (e.g. total suspended solids, turbidity, transparency, chlorophyll a, dissolved oxygen, conductivity and total hardness) in an upstream-downstream direction; 2) increased hydrological connectivity may have favored biological invasion (e.g. Tridentiger bifasciatus) and promoted a potential biotic homogenization among the impounded lakes; and 3) there was a pattern of decreased fish abundance and biomass from the upstream to downstream lakes with fish communities strongly driven by changing water quality patterns across the impounded lakes. These findings improve our understanding of ecological impacts of large-scale hydraulic projects and provide a significant basis for water agencies with similar water transfer systems to optimize their water transfer management in order to minimize ecological impacts.

MiR-128-3p mediates TNF-α-induced inflammatory responses by regulating Sirt1 expression in bone marrow mesenchymal stem cells.

Tumor Necrosis Factor α (TNF-α), a multifunctional pro-inflammatory cytokine, is produced by macrophages/monocytes during acute inflammation, and plays a critical role in orchestrating the cytokine cascade in various inflammatory diseases. Previous studies demonstrated that TNF-α induces inflammatory responses in bone marrow mesenchymal stem cells (BMSCs) transplantation, leading to unsatisfactory effects and limit the clinical use of BMSCs. MicroRNAs are reported to involve in inflammation by regulating the expression of their targets in inflammatory response pathway. However, whether microRNAs mediate TNF-α-induced inflammatory responses in BMSCs remains elusive. Here, we found that TNF-α treatment induced an inflammatory response by increasing the levels of key inflammatory mediators, including IL-6, IL-1ß, matrix metalloproteinase 9 (MMP9) and monocyte chemotactic protein-1 (MCP-1) in BMSCs. Moreover, real-time PCR result showed dramatically up-regulation of miR-128-3p after exposure to TNF-α. Interestingly, miR-128-3p over-expression exacerbated the TNF-α-induced inflammatory response, while suppression of miR-128-3p effectively eliminated the inflammatory response in BMSCs. Bioinformatic analysis identified sirtuin 1 is a direct target of miR-128-3p. Up-regulation of sirtuin 1 induced by resveratrol also diminished the TNF-α-induced inflammatory response in BMSCs. Altogether, our results indicated that miR-128-3p targets sirtuin 1 to mediate the TNF-α-induced inflammatory response in BMSCs, which may provide new strategies to protect against inflammatory-dependent impairments in BMSCs.

Eutrophication and heavy metal pollution patterns in the water suppling lakes of China's south-to-north water diversion project.

This study used non-supervised machine learning self-organizing maps (SOM) in conjunction with traditional multivariate statistical techniques (e.g., hierarchical cluster analysis, principle component analysis, Pearson's correlation analysis) to investigate spatio-temporal patterns of eutrophication and heavy metal pollution in the water supplying lakes (i.e., the Gao-Bao-Shaobo Lake, GBSL) of the eastern route of China's South-to-North Water Diversion Project (SNWDP-ER). A total of 28 water quality parameters were seasonally monitored at 33 sampling sites in the GBSL during 2016 to 2017 (i.e., 132 water samples were collected in four seasons). The results indicated that: 1) spatially, the western and south-western GBSL was relatively more eutrophic and polluted with heavy metals; and 2) temporally, the lakes suffered from high risks of heavy metal contamination in spring, but eutrophication in summer while water quality in winter was the best among the four seasons. Two main potential sources of pollution and transport routes were identified and discussed based on the pollution patterns. These findings contributed considerably to providing in-depth understanding of water pollution patterns, as well as potential pollution sources in the water-supplying region. Such understanding is crucial for developing pollution control and management strategies for this mega inter-basin water transfer project.

Impacts of hatchery-reared mandarin fish Siniperca chuatsi stocking on wild fish community and water quality in a shallow Yangtze lake.

Mandarin fish Siniperca chuatsi, a valuable piscivorous fish, have been stocked into many lakes in China since the 1990s. This study did the first attempt to evaluate the ecological effects of hatchery-reared mandarin fish stocking in the Yangtze River basin lakes. Our study demonstrated a significant change in fish community composition after mandarin fish stocking, but no fish extinction was observed. No significant difference was observed in the total density of 13 forage fish before and after mandarin fish stocking, but the total biomass showed a significant decline after mandarin fish stocking. Significant differences in length-frequency distributions were observed for Carassius auratus, Pseudorasbora parva and Toxabramis swinhonis captured before and after stocking mandarin fish. No significant change in habitat distribution was detected before and after mandarin fish stocking. A marked decline in total nitrogen and a slight decline in total phosphorus were observed while a slight increasing trend for Secchi depth was found after stocking. Our findings suggested that mandarin fish stocking can increase predation pressure on forage fish and subsequently optimize the food web structure. Also, mandarin fish stocking has the potential to improve water quality and may be a feasible strategy to alleviate eutrophication of shallow Yangtze lakes.