Plastics have been accumulated offshore and in the deep oceans at an unprecedented scale. Microbial communities have colonized the plastisphere, which has become a reservoir for both antibiotic and ...metal resistance genes (ARGs and MRGs). This is the first analysis of the diversity, abundance, and co-occurrence of ARGs and MRGs, and their relationships within the microbial community, using metagenomic data of plastic particles observed in the North Pacific Gyre obtained from the National Centre for Biotechnology Information Sequence Read Archive database. The abundance of ARGs and MRGs in microbial communities on the plastics were in the ranges 7.07 × 10−4–1.21 × 10−2 and 5.51 × 10−3–4.82 × 10−2 copies per 16S rRNA, respectively. Both the Shannon-Wiener indices and richness of ARGs and MRGs in plastics microbiota were significantly greater than those of ARGs and MRGs in seawater microbiota in the North Pacific Gyre via one-way analysis of variance. Multidrug resistance genes and multi-metal resistance genes were the main classes of genes detected in plastic microbiota. There were no significant differences in the abundance or diversity of ARGs and MRGs between macroplastics biota and microplastics biota, indicating that particle size had no effect on resistance genes. Procrustes analysis suggested that microbial community composition was the determining factor of the ARG profile but not for MRG. Some ARGs and MRGs had a higher incidence of non-random co-occurrence, suggesting that the co-effects of selection for antibiotic or metal resistance are important factors influencing the resistome of the microbiota on the plastic particles.
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•Plastic size does not influence the abundance and diversity of resistance genes.•Metal resistance genes had higher abundances than antibiotic resistance genes.•Plastics are a reservoir for metal resistance genes and antibiotic resistance genes.•Bacterial community driving ARG composition but not for MRG profile•Flavobacteriaceae family bacteria are potential host for ARGs and MRGs.
Antibiotic resistance genes (ARGs) and microplastics in the environment are of great public concern due to their potential risk to human health. Microplastics can form distinct bacterial communities ...and absorb pollutants from the surrounding environment, which provide potential hosts and exert possible selection pressure of ARGs. We provide a practical evaluation of the scientific literature regarding this issue. The occurrence and transport of ARGs on microplastics in wastewater treatment plants, aquatic, terrestrial, and air environments were summarized. Selective enrichment of ARGs and antibiotic resistance bacteria on microplastics have been confirmed in different environments. Aggregates may be crucial to understand the behavior and transport of ARGs on microplastics, especially in the aquatic and terrestrial environment. Microplastics could be a carrier of ARGs between the environment and animals. Accumulation of pollutants and dense bacterial communities on microplastics provide favorable conditions for higher transfer rate and evolution of ARGs. More studies are still needed to understand the enrichment, transport, and transfer of ARGs on microplastics and provide a fundamental basis for evaluating their exposure health risk to humans.
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•ARGs on microplastics in WWTPs, water, soil, and air were summarized.•Distinct ARG composition on microplastics was due to selective enrichment.•Aggregates are crucial to study the transport and transfer of ARGs on microplastic.
In order to make up for the problems of low production efficiency, high labor cost, serious environmental pollution, and low degree of informatization of traditional tunnel construction method, an ...intelligent identification building system of prefabricated tunnel structure is proposed. Based on BIM Technology and integrating advanced concepts and technologies in the construction industry and management field, an intelligent construction system of prefabricated tunnel structure based on BIM is proposed, the characteristics, functions, and values of each component are introduced, and the overall architecture of the system is established, which can provide technical support for the whole life cycle construction, operation, and maintenance of prefabricated railway tunnel. Only 68% of architectural designers know BIM Technology, while only 4% of designers really use or are using BIM Technology to participate in prefabricated architectural design. Through this research, the use frequency of BIM can be greatly increased and work efficiency can be improved. To meet the requirements of railway tunnel construction for intelligent construction in the new era, the new technology and new ideas also lead the further scientific and technological innovation in tunnel engineering to a certain extent, which meets the actual needs of the development of intelligent railway construction technology and has a practical significance of improving quality and efficiency.
Although environmental research has recently begun to focus on the ubiquity of microplastics in terrestrial systems, there is still lack of comprehensive data which describe microplastics levels in ...soils and the factors influencing the distribution of this contaminant. Here, we show that microplastics contamination (3877 ± 2356 p kg1) is omnipresent in numerous soil samples collected along the Yangtze River. Subsoils (4005 ± 2472 p kg1) showed higher levels of microplastics than topsoils (3748 ± 2301 p kg1), while polyamide (32%) was the most commonly found polymer in the samples. Small microplastics particles (< 200 µm) accounted for approximately 70% of the microplastics detected in subsoils. In terms of shape, microfragments were the most common type of microplastic particle, accounting for 34% of total microplastics, followed by microfibers (30%). Furthermore, microplastics contamination was found to be positively correlated with both the population of the study area and precipitation, yet negatively correlated with the elevation of the sampling site. Our study represents the first large-scale study of microplastic contamination in riparian soils along the Yangtze River, and provides important data regarding the ecotoxicology and ecosystem effects of microplastics in terrestrial environments.
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•Global terrestrial environments were widely contaminated by microplastics.•Subsoils showed higher microplastics levels than topsoils.•Subsoils contained more small microplastics particles (< 200 µm) than topsoils.•Microplastic contamination was positively related to population density and precipitation.
Freshwater lakes provided an ideal media for the accumulation and propagation of antibiotic resistance genes (ARGs), because they were susceptible to anthropogenic impacts. Land reclamation and ...urbanization exerted severe anthropogenic impacts on lakes from middle and lower reaches of the Yangtze River, China over the past decades. In this study, 15 lakes in the region were selected to understand the level and variability of ARGs. Proportion of different land use types was applied to display the land reclamation and urbanization around each lake. For sulfonamide resistance (sul) genes, sul1 had the highest relative abundance in sediments, with maximum 2.11 × 10−1 copies/16SrRNA copy in Gehu Lake. For tetracycline resistance (tet) genes, tetG had the highest average value of relative abundance (4.74 × 10−3 copies/16SrRNA copy), followed by tetB, tetA, tetQ and tetM. Class I integron (intI1) played an important role in acquisition and dissemination of sul1 and tetG. Sediment characteristics (moisture, density, total nitrogen, total carbon, ammonium, and nitrate) were found to have no significant effect on ARG distribution. Taihu Lake and Yangcheng Lake which exhibited high sul and tet genes had the high proportion of built-up land use.
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•Diversity and abundance of ARGs in 15 lakes along the Yangtze River were shown.•Redundancy analysis was used to analyze the ARG abundance determined by qPCR.•The lakes with high proportion of built-up land use had high ARG abundance.•Sediment characteristics had no significant effect on ARG distribution.
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•The accumulation of nanoplastics lead to adverse effects on soil fauna.•Positively charged and ecologically relevant nanoplastics exerted significant toxicity.•Immune defense was ...provoked to counteract the challenge of nanoplastics.•Aggregations of nanoplastics in lysosomes induced coelomocyte death.
Nanoplastics (NPs) are increasingly perceived as an emerging threat to terrestrial environments, but the adverse impacts of NPs on soil fauna and the mechanisms behind these negative outcomes remain elusive. Here, a risk assessment of NPs was conducted on model organism (earthworm) from tissue to cell. Using palladium-doped polystyrene NPs, we quantitatively measured nanoplastic accumulation in earthworm and investigated its toxic effects by combining physiological assessment with RNA-Seq transcriptomic analyses. After a 42-day exposure, earthworm accumulated up to 15.9 and 143.3 mg kg−1 of NPs for the low (0.3 mg kg−1) and high (3 mg kg−1) dose groups, respectively. NPs retention led to the decrease of antioxidant enzyme activity and the accumulation of reactive oxygen species (O2− and H2O2), which reduced growth rate by 21.3 %–50.8 % and caused pathological abnormalities. These adverse effects were enhanced by the positively charged NPs. Furthermore, we observed that irrespective of surface charge, after 2 h of exposure, NPs were gradually internalized by earthworm coelomocytes (∼0.12 μg per cell) and mainly amassed at lysosomes. Those agglomerations stimulated lysosomal membranes to lose stability and even rupture, resulting in impeded autophagy process and cellular clearance, and eventually coelomocyte death. In comparison with negatively charged nanoplastics, the positively charged NPs exerted 83 % higher cytotoxicity. Our findings provide a better understanding of how NPs posed harmful effects on soil fauna and have important implications for evaluating the ecological risk of NPs.
A global survey was performed with 122 aquatic metagenomic DNA datasets (92 lake water and 30 seawater) obtained from the Sequence Read Archive (SRA). Antibiotic resistance genes (ARGs) and metal ...resistance genes (MRGs) were derived from the dataset sequences via bioinformatic analysis. The relative abundances of ARGs and MRGs in lake samples were in the ranges ND (not detected)–1.34 × 100 and 1.22 × 10−3–1.98 × 10−1 copies per 16S rRNA, which were higher than those in seawater samples. Among ARGs, multidrug resistance genes and bacitracin resistance genes had high relative abundances in both lake and sea water samples. Multi-metal resistance genes, mercury resistance genes and copper resistance genes had the greatest relative abundance for MRGs. No significant difference was found between epilimnion and hypolimnion in abundance or the Shannon diversity index for ARGs and MRGs. Principal coordinates analysis and permutational multivariate analysis of variance (PERMANOVA) test showed that stratification and geography had significant influence on the composition of ARGs and MRGs in lakes (p < 0.05, PERMANOVA). Coastal seawater samples had significantly greater relative abundance and a higher Shannon index for both ARGs and MRGs than deep ocean and Antarctic seawater samples (p < 0.05, Kruskal-Wallis one-way ANOVA), suggesting that human activity may exert more selective pressure on ARGs and MRGs in coastal areas than those in deep ocean and Antarctic seawater.
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•Global survey of resistance genes in lakes and seas was carried out.•The relative abundances of ARGs and MRGs in lakes were higher than seas.•Stratification had influences on the composition of ARGs and MRGs in lakes.•Human activity exerts great selective pressure on ARGs and MRGs in coastal areas.•High relative abundance of ARG and MRG types in lakes and seas was identified.
•Riparian denitrification was positively related to soil nitrate concentration.•Riparian denitrification increased with the proportion of catchment agriculture.•Riparian zones played an important ...role in removing N from agricultural runoff.
Riparian zones play an important role in reducing nitrogen (N) loading to rivers and streams primarily through soil denitrification which reduces nitrate (NO3–) to nitrous oxide (N2O) and dinitrogen (N2) gases. Although the relationships between local environments and soil denitrification are well understood, relatively little is known about the indirect effects of landscape factors (e.g., catchment agriculture) on the soil denitrification of riparian zones. In this study, we used the acetylene block technique to measure the denitrification potential and net N2O production of soils collected from 62 riparian sites in 15 subtropical rivers of varying catchment land uses. The results indicated that, among the local factors studied, the soil moisture, organic matter and NO3– concentrations were positively associated with both the denitrification potential and N2O production rate. Agricultural riparian zones had a denitrification potential (2.81±1.01ngNg−1h−1) significantly higher than forested riparian zones (0.66±0.24ngNg−1h−1). Additionally, the riparian denitrification potential increased with the percentage of agriculture in the catchments (R=0.53, P<0.05). Structural equation modeling revealed that the indirect effects of catchment agriculture on the riparian denitrification potential and N2O production rate were mediated primarily through soil NO3–. Our findings suggest that, compared to forested riparian zones, agricultural riparian zones have greater potential to remove N from polluted runoff. The conversion of original vegetation to agricultural lands in catchments may have a profound impact on the soil N cycles and NO3– removal capacity of riparian zones.
Abstract
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.
Lake eutrophication is influenced by both anthropogenic and natural factors. Few studies have examined relationships between eutrophication parameters and natural factors at a large spatial scale. ...This study explored these relationships using data from 103 lakes across China. Eutrophication parameters including total nitrogen (TN), total phosphorus (TP), TN:TP ratio, chemical oxygen demand (CODMn), chlorophyll-a (Chl-a), Secchi depth (SD), and trophic state index (TSI) were collected for the period 2001-2005. Sixteen natural factors included three of geographic location, five of lake morphology, and eight of climate variables. Pearson correlation analysis showed that TP and TSI were negatively related to elevation, lake depth, and lake volume, and positively related to longitude. All eutrophication parameters, except for CODMn and Chl-a, showed no significant correlation with climate variables. Multiple regression analyses indicated that natural factors together accounted for 13-58% of the variance in eutrophication parameters. When the 103 study lakes were classified into different groups based on longitude and elevation, regression analyses demonstrated that natural factors explained more variance in TN, TP, CODMn, Chl-a, and TSI in western lakes than in eastern lakes. Lake depth, volume, elevation, and mean annual precipitation were the main predictors of eutrophication parameters for different lake groups. Although anthropogenic impacts such as point- and nonpoint-source pollution are considered as the main determinants of lake eutrophication, our results suggest that some natural factors that reflect lake buffer capacity to nutrient inputs can also play important roles in explaining the eutrophication status of Chinese lakes.
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