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Rural drainage ditches serve as important sinks for heavy metals and antibiotics. However, the combined effects of heavy metals and antibiotics on ecological processes and functions in ditches remain unclear. We studied the combined effects of cadmium and doxycycline on nitrification, denitrification, anaerobic ammonia oxidation, and nitrous oxide emission rates in constructed ditch wetlands during 84 days. Results show that combined pollution decreased denitrification and anaerobic ammonia oxidation rates, but increased nitrous oxide production rates. The addition of either cadmium or doxycycline decreased the glucokinase and glyceraldehyde-3-phosphate dehydrogenase activities, and their combined pollution had a higher impact on adenosine triphosphate than on nicotinamide adenine dinucleotide. Moreover, the activities of the electron transport system, nitrate reductase, and nitrite reductase were enhanced by short-term pollutant exposure, but inhibited by long-term pollutant exposure. Structural equation modelling further revealed that electron production and transport impacted the rates of denitrification, anaerobic ammonia oxidation, and nitrous oxide production directly and indirectly by changing the activities of nitrate and nitrite reductases. [ABSTRACT FROM AUTHOR]

Machinable ceramics are typical brittle materials, and their surface formation mechanism during machining has not been well revealed. Currently, there are few theoretical models of surface roughness for turning brittle materials. Through experiments with turning machinable ceramics, the surface formation mechanism of brittle materials is investigated from macro and micro perspectives. The combined action of tool and workpiece interference, elastic recovery, and crushing craters creates the machined surface of brittle materials. The initial surface angle and length, the deflection surface angle and length, and the extension length of the upward-extending surface were calculated based on the biaxial stress analytical method, the fracture criterion of the stress intensity factor, and the energy conservation principle. By quantitatively describing the cross-sectional shape of crushing craters, a brittle surface roughness model is established with the combination of actual cutting layer parameters, tool angle, material properties, tool-workpiece interference relationship, and elastic recovery. The experimental validation results show that the brittleness model is more accurate and consistent in trend compared to the traditional geometric model and the theoretical model of crushing with simplified crushing crater shapes. The new model can be utilized as a basis for the theoretical prediction of surface roughness in the cutting of brittle materials. [ABSTRACT FROM AUTHOR]

miR-30c functions as a tumor suppressor gene in the majority of tumors, including gliomas. In our study, we discovered that the expression levels of miR-30c in glioma tissues and plasma prior to surgery were lower than those in normal brain tissue following brain injury decompression and in plasma in healthy volunteers. The low expression of miR-30c was closely aligned with the WHO grade, tumor size, PFS, and OS. Additionally, the miR-30c expression level in tumor tissue was positively correlated with the levels in preoperative plasma. In cell biology experiments, miR-30c inhibited EMT and proliferation, migration, and invasion of glioma cells. Analysis of databases of miRNA target genes, real-time quantitative PCR, western blotting, and dual luciferase reporter assays demonstrated that Notch1 is the direct target gene of miR-30c. An inhibitor and shRNA-Notch1 were cotransfected into glioma cells, and it was found that shRNA-Notch1 reduced the enhancement of inhibitors of EMT and proliferation, migration, and invasion of glioma cells. Therefore, we believe that when utilized as a tumor suppressor gene, miR-30c can inhibit EMT and the proliferation, migration, and invasion of glioma cells by directly acting on Notch1 at the posttranscriptional level and that it is a potential diagnostic and prognostic marker. [ABSTRACT FROM AUTHOR]

Land degradation and restoration strongly influence terrestrial soil organic carbon (SOC) dynamics. However, the underlying mechanisms are not well understood. Here, based on a meta-analysis of 803 observations from 138 studies worldwide, our data analyses suggest that C-degrading enzymes play a crucial role in regulating SOC dynamics under land degradation and restoration. Our result showed that decreased cellulase activity but unchanged ligninase activity was associated with land degradation, whereas higher increased cellulase activity compared with ligninase activity was associated with land restoration. Consequently, the ligninase-to-cellulase ratios were higher under land degradation and lower under land restoration. Also, the specific enzyme activity (the amount of enzyme produced per unit microbial biomass) was greater under land degradation but lower under land restoration. By comparison with the short-term (≤ 30) land degradation, the long-term (> 30 years) land degradation significantly increased the ligninase-to-cellulase ratio. On the contrary, the long-term land restoration exerted a more negative effect on the ligninase-to-cellulase ratio. The increases in the specific enzyme activity and ligninase-to-cellulase ratio were tightly correlated with decreases in SOC content under land degradation. A similar correlation was also found between decreases in specific enzyme activity and ligninase-to-cellulase ratio and increases in SOC content under land restoration. Overall, the decrease of SOC storage under land degradation is not only due to the low plant inputs, but also likely because of the accelerated degradation of recalcitrant C pools. However, the reverse applies for land restoration. The novel insights provided by our results contribute to the understanding of microbial mechanisms underlying the changes in SOC accumulation in response to land-use changes. [ABSTRACT FROM AUTHOR]

The significance of the polypeptide N-acetyl-galactosaminyl transferase-3 (GalNAc-T3) and mucin 1 (MUC1) in solitary pulmonary adenocarcinoma (SPA) initially diagnosed as malignant solitary pulmonary nodule (≤ 3 cm), especially as a combined predictor of prognosis and recurrence, was explored in this study. A retrospective analysis of 83 patients with SPA (≤ 3 cm), which revealed postoperative pathological diagnosis was lung adenocarcinoma after complete resection. Immunohistochemical staining was used to detect the expression of GalNAc-T3 and MUC1 in primary tumor specimens. The relationship between expression and various clinicopathological factors was analyzed, as well as the effects of patients' overall survival (OS) and disease-free survival (DFS). In all patients, GalNAc-T3 was highly expressed in 53 (63.9%) cases; MUC1 was highly expressed in 31 (37.3%) cases. The GalNAc-T3 expression was correlated with differentiation, pathological risk group, N stage, and TNM stage. The group with high GalNAc-T3 expression and low MUC1 expression (GalNAc-T3Hig/MUC1Low) is correlated to pathological differentiation and has a trend related to the TNM stage. The patients with better differentiation, lower pathological risk group, lower N stage, and GalNAc-T3 high expression had better overall survival, especially the GalNAc-T3Hig/MUC1Low group. Moreover, the moderate differentiation, N3 stage, and GalNAc-T3Hig/MUC1Low group were independent predictive factors for OS. Besides, patients with lower N stage, lower TNM stage, higher GalNAc-T3 expression got better disease-free survival (DFS), especially the GalNAc-T3Hig/MUC1Low group. The GalNAc-T3Hig/MUC1Low group was an independent predictive factor for DFS. In conclusion, GalNAc-T3 and MUC1 were combined predictors of prognosis and recurrence in SPA (≤ 3 cm). [ABSTRACT FROM AUTHOR]

Microplastics in the biosphere are currently of great environmental concern because of their potential toxicity for aquatic biota and human health and association with pathogenic microbiota. Microplastics can occur in high abundance in all aquatic environments, including oceans, rivers and lakes. Recent findings have highlighted the role of microplastics as important vectors for microorganisms, which can form fully developed biofilms on this artificial substrate. Microplastics therefore provide new microbial niches in the aquatic environment, and the developing biofilms may significantly differ in microbial composition compared to natural free-living or particle-associated microbial populations in the surrounding water. In this article, we discuss the composition and ecological function of the microbial communities found in microplastic biofilms. The potential factors that influence the richness and diversity of such microbial microplastic communities are also evaluated. Microbe-microbe and microbe-substrate interactions in microplastic biofilms have been little studied and are not well understood. Multiomics tools together with morphological, physiological and biochemical analyses should be combined to provide a more comprehensive overview on the ecological role of microplastic biofilms. These new microbial niches have so far unknown consequences for microbial ecology and environmental processes in aquatic ecosystems. More knowledge is required on the microbial community composition of microplastic biofilms and their ecological functions in order to better evaluate consequences for the environment and animal health, including humans, especially since the worldwide abundance of microplastics is predicted to dramatically increase. Key Points • Bacteria are mainly studied in community analyses: fungi are neglected. • Microbial colonization of microplastics depends on substrate, location and time. • Community ecology is a promising approach to investigate microbial colonization. • Biodegradable plastics, and ecological roles of microplastic biofilms, need analysis. [ABSTRACT FROM AUTHOR]

Ecological stoichiometry represents the balance of nutrient elements under ecological interactions, which are crucial for biogeochemical cycles in ecosystems. Little is known about carbon (C), nitrogen (N), and phosphorus (P) ecological stoichiometry in aboveground biomass, roots, and soil, especially in the subtropical riparian wetlands. Here, eight dominate plant communities in riparian wetlands were chosen, and C, N, and P contents, and C:N:P ratios of aboveground biomass, roots, and soil were investigated. The results demonstrated that plant community had remarkable effects on the C:N:P stoichiometry in aboveground biomass, roots, and soil, which varied widely. C, N, and P concentrations in aboveground biomass were mostly higher than that in roots, while no significant difference was detected in C:N:P ratios. Moreover, there were higher soil C, N, and P contents in Cannabis indica plant communities; while lower soil N:P ratios suggested that riparian wetlands were more susceptible to N limitation, rather than P. Pearson correlation analysis and redundancy analysis (RDA) showed that there were strong associations among C, N, and P contents, and C:N:P ratios in aboveground biomass, roots, and soil, indicating that C, N, and P ecological stoichiometry of aboveground biomass were regulated by soil C, N, and P contents through the roots. In addition, the contents of C and N, and N and P exhibited a strong relationship according to linear regression. These findings suggested that the interactions among the C, N, and P stoichiometry were existed in the plant-soil system. [ABSTRACT FROM AUTHOR]

In 2017, a clinical disease outbreak resulted in substantial mortality of adults and larvae of cultured Chinese rice-field eels (Monopterus albus) on a farm in Hubei, Central China. A rhabdovirus was isolated from moribund specimens, and typical clinical symptoms associated with an outbreak included an enlarged and swollen head. This differed from previous observations. Histological changes included necrosis and cavities of various sizes within the brain and kidney. Homogenized tissues of diseased Chinese rice-field eels were screened for viral isolation using six different fish cell lines. A rhabdovirus was isolated following observation of cytopathic effect (CPE) in a gibel carp brain (GiCB) cell line and confirmed by RT-PCR. Electron microscopy showed large numbers of rhabdovirus-shaped particles in the cytoplasm of the brain cells of the diseased Chinese rice-field eels and in the infected GiCB cell line. This virus has been named "Chinese rice-field eel rhabdovirus" (CrERV), and the complete nucleotide sequence of CrERV was cloned. This rhabdovirus is composed of 11,545 nucleotides with the following genomic organization: 3′-N-P-M-G-L-5′. The genes are separated by conserved gene junctions, and phylogenetic analysis of the L sequence revealed that CrERV forms a separate branch with Siniperca chuatsi rhabdovirus (SCRV) and hybrid snakehead rhabdovirus C1207 (HSHRV-C1207). This is the first report of the complete sequence of CrERV from the Chinese rice-field eel in China. [ABSTRACT FROM AUTHOR]

Eutrophication has caused many serious environmental issues in lakes. Submerged vegetation, which plays a key role in maintaining the clear water state of shallow lakes, is strongly influenced by water quality and sediment properties. In this study, we seasonally investigated the water quality, sediment properties and submerged plant communities in 18 sites in Lake Honghu of China, an internationally important wetland under the Ramsar Convention. Results indicated that most of the water quality parameters and sediment properties showed no significant difference among the three site types (i.e., perennially vegetated, seasonally vegetated and unvegetated). However, the Secchi depth in perennially and seasonally vegetated sites was significantly higher that in unvegetated sites. By contrast, season had a strong effect on most of the water quality parameters and sediment properties (e.g., water chlorophyll-a concentration). For submerged vegetation, species richness and biomass showed significant spatial but not seasonal differences, with higher richness and biomass in perennially vegetated sites. Canonical correspondence analysis indicated that the distribution of submerged plants was mainly determined by water NH4+ concentration and water depth. Our findings suggest that restoration of submerged vegetation in Chinese eutrophic lakes may be a feasible method for improving water environments and enhancing ecological functions. [ABSTRACT FROM AUTHOR]

Sediment denitrification is the dominant nitrogen removal pathway in many aquatic habitats and can be regulated by local-, landscape-, and regional-scale factors. However, the mechanisms for how these multiple scale factors and their interactions affect the sediment denitrifying communities remain poorly understood. In this study, we investigated the community composition, diversity, and abundance of nitrite reductase genes ( nirK and nirS)-encoding denitrifiers in 74 sediment samples from 22 Yangtze lakes using clone library and quantitative PCR techniques. Information of location, climate, catchment land use, water quality, sediment properties, and plant communities at each sampling site was analyzed to elucidate the effects of regional, landscape, and local factors on the characteristics of sediment denitrifying communities. Results of canonical correspondence analysis indicated that local factors were the key determinants of denitrifying community composition, accounting for over 20% of the total variation. Additionally, certain regional and landscape factors, including elevation and catchment built-up land, were also significantly related to the composition of denitrifying communities. Variance partitioning analyses revealed that diversity and abundance in the nirK denitrifier community were largely influenced by local factors, while those in the nirS community were controlled by both local and regional factors. Our findings highlight the importance of using different scale factors to explain adequately the composition and structure of denitrifying communities in aquatic environments. [ABSTRACT FROM AUTHOR]

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in regulating the nitrification process in lake ecosystems. However, the relative effects of climate, catchment land use and local conditions on the sediment ammonia-oxidizing communities in lakes remain unclear. In this study, the diversity and abundance of AOA and AOB communities were investigated in ten Yangtze lakes by polymerase chain reaction (PCR), clone library and quantitative PCR techniques. The results showed that the abundances of both AOA and AOB in bare sediments were considerably but not significantly higher than those in vegetated sediments. Interestingly, AOB communities were more sensitive to changes in local environmental factors and vegetation characteristics than were AOA communities. Amongst climate and land use variables, mean annual precipitation, percentage of agriculture and percentage of vegetation were the key determinants of AOB abundance and diversity. Additionally, total organic carbon and chlorophyll- a concentrations in lake water were significantly related to AOB abundance and diversity. The results of the ordination analysis indicated that 81.2 and 84.3% of the cumulative variance for the species composition of AOA and AOB communities could be explained by the climate, land use and local factors. The climate and local environments played important roles in shaping AOA communities, whereas catchment agriculture and water chlorophyll- a concentration were key influencing factors of AOB communities. Our findings suggest that the composition and structure of sediment ammonia-oxidizing communities in Yangtze lakes are strongly influenced by different spatial scale factors. [ABSTRACT FROM AUTHOR]

The majority of rivers in the world have been dammed, and over 45,000 large reservoirs have been constructed for multiple purposes. Riparian and reservoir shorelines are the two most important wetland types in a dammed river. To date, few studies have concerned the heavy metal pollution in wetland soils of these river-reservoir systems. In this study, we measured the concentrations of ten heavy metals (Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, and Zn) in surface soils collected from riparian and reservoir shorelines along the Han River in different seasons. Our results found that the Co, Cu, and Ni concentrations in riparian wetlands were significantly lower than those in reservoir shorelines. In riparian wetlands, only soil Sr concentration significantly increased after summer and autumn submergence. Multivariate statistical analyses demonstrated that Ba and Cd might originate from industrial and mining sources, whereas Sr and Mn predominantly originated from natural rock weathering. The ecological risk assessment analysis indicated that both riparian and reservoir shorelines along the Han River in China exhibited a moderate ecological risk in soil heavy metals. The upper Han River basin is the water resource area of China's Middle Route of the South-to-North Water Transfer Project. Therefore, to control the contamination of heavy metals in wetland soils, more efforts should be focused on reducing the discharge of mining and industrial pollutants into the riparian and reservoir shorelines. [ABSTRACT FROM AUTHOR]

Increasing population is generally responsible for the degraded river ecosystem. Using regression models and mathematical functions, the research quantitatively estimated the population and elevational gradient effects on river water quality during nine surveys from 2006 to 2008 in the Jinshui River basin of the South Qinling Mts., China. The total factor scores at 11 different sampling sites were calculated in factor analysis and first used as pollution index to represent the water quality levels. Population and elevational gradient both significantly linked with most water quality variables and pollution index in correlation analysis and explained 36.5–77.8 % of the total variances in regression analysis, indicating that human activities were gradually frequent with population growth and affected the input and output of pollutants in river water. On the basis of regression models and quadratic functions among population, elevational gradient, and pollution index, the population capacity of the river basin was estimated as 1815 people, and the threshold value of elevation was calculated as 1174 m. The results of multivariate linear models further confirmed that population and population distribution had direct influences on river water quality. This study will facilitate the ecosystem management for mountainous streams and provide quantitative models for understanding and mitigating human impacts on river system. [ABSTRACT FROM AUTHOR]

Ponds are widely used as stormwater treatment facilities to retain contaminants, including metals, and to improve water quality throughout the world. However, there is still a limited understanding of the effects of surrounding land use on metal accumulation in pond environments and organisms. To address this gap, we measured the concentrations of nine metals (i.e., Al, Ba, Ca, K, Li, Mg, Na, Se, and Sr) in water, sediments, and submerged plants collected from 37 ponds with different surrounding land uses in southwestern China and assessed the metal accumulation capacity of four dominant submerged plant species. Our results showed that Al, Ca, and K concentrations in the water were above drinking water standards. In the sediments, the average concentrations of Ca and Sr were higher than the corresponding soil background values. Ceratophyllum demersum L. could accumulate more K in aboveground biomass than Myriophyllum spicatum L. and Potamogeton maackianus A. Benn. The K concentration in submerged plants was positively influenced by the corresponding metal concentration in the water and negatively influenced by water temperature. Among the nine studied metals, only the water K concentration in ponds receiving agricultural runoff was significantly higher than that for ponds receiving urban and forested runoff. This result suggests that surrounding land use types have no significant effect on metal accumulation in sediments and submerged plants in the studied ponds. A large percentage of the metals in these ponds may be derived from natural sources such as the weathering of rocks. [ABSTRACT FROM AUTHOR]

Denitrification in lake sediments removes nitrogen and releases NO to the atmosphere, contributing to global warming. However, the rates and controls of sediment denitrification and NO production are still poorly understood in lakes. In this study, we measured potential denitrification, unamended denitrification and NO production rate in sediments which were collected from 68 sites in 20 Chinese plateau lakes of varying watershed land uses. The result showed that potential denitrification rate of human-dominated lakes (37.94 ± 8.91 ng N g h) was significantly higher than that of reference lakes (18.50 ± 3.22 ng N g h). In addition, potential denitrification rate was positively related to the proportion of human land uses in watersheds. At the lake level, unamended denitrification and NO production rates were significantly related to water chemistry or sediment properties (e.g., conductivity and sediment total nitrogen). Water chemistry and sediment properties together accounted for 0-69 % of the variance in denitrification and NO production rates. Variance partitioning showed that unamended denitrification and NO production rates in human-dominated lakes were controlled primarily by sediment properties, while in reference lakes were generally controlled by water chemistry. Our findings suggest that Chinese plateau lakes can remove large quantities of nitrogen through sediment denitrification and produce small amounts of NO. The relative contributions of water chemistry and sediment properties to the lake denitrification and NO production vary widely. [ABSTRACT FROM AUTHOR]

Introduction: Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial-temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll- a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. Discussion: Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegetation, all eutrophication parameters except chlorophyll- a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social-economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial wastewaters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region. [ABSTRACT FROM AUTHOR]