Starkpoe1737

ation.Single-atom nanozymes (SAzymes) as a new class of efficient nanozymes have attracted extensive research interest due to their high catalytic activity and specificity. However, it is challenging to develop a novel nanoenzyme with high activity, good stability and reproducibility. In this paper, the nitrogen and sulfur coordinated Fe-N/S-C SAzymes were synthesized using peanuts shells as carbon, nitrogen and sulfur source. It shows high oxidase-like activities due to the doping of S induced geometric and electronic effects, which is further confirmed by density functional theory calculations. The prepared Fe-N/S-C SAzymes with the remarkable oxidase-mimicking activity could oxidize TMB to blue oxTMB, but the GSH can inhibit the oxidation of TMB resulting in blue fading. However, when Hg2+ is added into above system, Hg2+-SH complexes are generated attributed to a high affinity between GSH and Hg2+, ultimately leading to blue recovery. Based on this phenomenon, we constructed a novel "on-off-on" colorimetric sensor for the simultaneous detection of GSH (off) and Hg2+ (on), and the signal is acquired by various modes such as naked eye, UV-Vis spectrometer and smartphone. The colorimetric detection mode based on a smartphone showed a good linear response from 10 to 80 μM for GSH with a detection limit of 3.92 μM, and for Hg2+ with a linear range of 1 nM-10 μM and LOD of 0.17 nM, which is more suitable for routine laboratory applications. More importantly, the proposed colorimetric sensor has been successfully applied to the detection of GSH and Hg2+ in real samples with good analytical performance. This work not only provides a simple and cost-effective method to detect GSH and Hg2+ but also makes a certain contribution to environmental protection.The fate of plastics in rivers is a key component of the global plastic cycle. Plastics entering freshwater ecosystems are colonized by microbial biofilms, and microbe-plastic interactions can influence ecosystem processes and plastic fate. While literature examining the role of geographic region on plastic biofilms is quickly expanding, research which covers large (i.e., continental) spatial scales and includes freshwater ecosystems is warranted. In addition, most research focuses on bacterial communities, while biofilm eukaryotes are less commonly studied. We assessed biofilm metabolism and community structure on plastic (foamed polystyrene and polyvinyl chloride; PVC) and natural substrates (unglazed ceramic tile) in urban streams spanning a nested geographic gradient in the continental United States. We measured biofilm biomass, community respiration, and chlorophyll a, in addition to assessing marker gene-based community diversity of bacterial, fungal, and algal assemblages. Results demonstrated some subtural substrates.With the rapid development of the mining industry, the pollution of heavy metal(loid)s in soils near copper (Cu) mining sites is a significant concern worldwide. However, the pollution status and probabilistic health risks of heavy metal(loid)s of soils associated with Cu mines, have rarely been studied on a global scale. In this study, eight heavy metal(loid) concentrations in soil samples taken near 102 Cu mining sites worldwide were obtained through a literature review. Based on this database, the heavy metal(loid) pollution and ecological risk in soils near Cu mines were evaluated. Most of the study sites exceeded the moderately to heavily polluted levels of Cu and Cd; compared to other regions, higher pollution levels were observed at sites in Oman, China, Australia, and the United Kingdom. Soil pollution by Cd, Pb, and Zn at agricultural sites was higher than that in non-agricultural sites. In addition, these heavy metal(loid)s produced a high ecological risk to soils around Cu mining sites in which the contribution of Cd, Cu, and As reached up to 46.5%, 21.7%, and 18.4%, respectively. The mean hazard indices of the eight heavy metal(loid)s were 0.209 and 0.979 for adults and children, respectively. The Monte Carlo simulation further predicted that 1.40% and 29.9% of non-carcinogenic risk values for adults and children, respectively, exceeded the safe level of 1.0. Moreover, 84.5% and 91.0% of the total cancer risk values for adults and children, respectively, exceeded the threshold of 1E-04. Arsenic was the main contributor to non-carcinogenic risk, while Cu had the highest exceedance of carcinogenic risk. Our findings indicate that the control of Cu, Cd, and As should be prioritized because of their high incidence and significant risks in soils near Cu mines. These results provide valuable inputs for policymakers in designing effective strategies for reducing the exposure of heavy metal(loid)s in this area worldwide.Chemical eradication of non-native species has become a widely used method to mitigate the potential negative impacts of altered competitive or predatory dynamics on biodiversity and natural ecosystem processes. However, the responses of non-target species can vary from rapid full recovery to delayed or absent recolonization, and little is known about the potential shifts in resource use and trophic diversity of native species following chemical treatments. We used a before-after-control-impact approach to study the effects of rotenone piscicide treatment on abundance and trophic niche of benthic invertebrates in three untreated and three treated lakes in central Norway, the latter group hosting non-native roach (Rutilus rutilus) and pike (Esox lucius) prior to rotenone treatment. Based on community composition data, the relative abundance of invertebrate grazers and collectors decreased while that of predators increased following fish removal in the treated lakes. The stable isotope data indicated minor shife treated lakes.Eutrophication has attracted extensive attention owing to its harmful effects to the organisms and aquatic environment. Studies on the functional microorganisms with the ability of simultaneously nitrogen (N) and phosphorus (P) removal is of great significance for alleviating eutrophication. Thus far, several strains from various genera have been reported to accomplish simultaneous N and P removal, which is primarily observed in Bacillus, Pseudomonas, Paracoccus, and Arthrobacter. The mechanism of N and P removal by denitrifying P accumulating organisms (DPAOs) is different from the traditional biological N and P removal. The denitrifying P removal (DPR) technology based on the metabolic function of DPAOs can overcome the problem of carbon source competition and sludge age contradiction in traditional biological N and P removal processes and can be applied to the treatment of urban sewage with low C/N ratio. This paper reviews the mechanism of N and P removal by DPAOs from the aspect of the metabolic pathways and enzymatic processes. The research progress on DPR processes is also summarized and elucidated. Further research should focus on the efficient removal of N and P by improving the performance of functional microorganisms and development of new coupling processes. This review can serve as a basis for screening DPAOs with high N and P removal efficiency and developing new DPR processes in the future.The use of serpentine biological weathering to capture atmospheric CO2 has attracted much attention. In the long-term mining activities in a serpentine mining area, a large amount of serpentine powder diffused into the surrounding forest and farmland soil. The study of the serpentine weathering in soils of different vegetative covers and the composition characteristics of soil carbonate has important implications for understanding the serpentine weathering and carbon sequestration under natural conditions. The microbial diversity on exposed rock serpentine surfaces and soil under different vegetative covers in the serpentine mining area in Donghai County, China was investigated by high-throughput sequencing technology, and the characteristics of serpentine weathering and soil carbonate in related area were also explored by XRF, XRD, SEM-EDS, and chemical analysis methods. The results showed that the richness and uniformity of the bacteria species community increased significantly with the increasing complexity of plant groups covering the rock surface, but the species richness and uniformity of fungi showed an overall declining trend. Furthermore, high‑magnesium calcite (HMC) is ubiquitous on the exposed rock surface and the soil under different vegetative covers in this area. Based on these results, combined with the verification test results of HMC fixed heavy metal ions, the model of serpentine weathering in serpentine mining soil to synthesize carbonate and fix heavy metal ions was developed. That is, with the increase in the degree of rock weathering and the colonization of plants, the soil and plants seem to shape jointly a relatively stable microbial community structure adapted to the environment of the serpentine mining area, which promotes the serpentine weathering coupled with the formation of HMC and immobilization of metal ions in the serpentine soil. This study provides a theoretical basis for the serpentine bio-weathering in the mine area to capture atmospheric CO2.Quorum sensing (QS) regulates various physiological processes in a cell density-dependent mode via cell-cell communication. Stenotrophomonas rhizophila DSM14405T having the diffusible signal factor (DSF)-QS system, is a plant growth-promoting rhizobacteria (PGPR) that enables host plants to tolerate saline-alkaline stress. However, the regulatory mechanism of DSF-QS in S. rhizophila is not fully understood. In this study, we used S. rhizophila DSM14405T wild-type (WT) and an incompetent DSF production rpfF-knockout mutant to explore the regulatory role of QS in S. rhizophila growth, stress responses, biofilm formation, and colonization under saline-alkaline stress. We found that a lack of DSF-QS reduces the tolerance of S. rhizosphere ΔrpfF to saline-alkaline stress, with a nearly 25-fold reduction in the ΔrpfF population compared with WT at 24 h under stress. Transcriptome analysis revealed that QS helps S. rhizophila WT respond to saline-alkaline stress by enhancing metabolism associated with the cell wall and membrane, oxidative stress response, cell adhesion, secretion systems, efflux pumps, and TonB systems. These metabolic systems enhance penetration defense, Na+ efflux, iron uptake, and reactive oxygen species scavenging. Additionally, the absence of DSF-QS causes overexpression of biofilm-associated genes under the regulation of sigma 54 and other transcriptional regulators. However, greater biofilm formation capacity confers no advantage on S. EKI-785 cell line rhizosphere ΔrpfF in rhizosphere colonization. Altogether, our results show the importance of QS in PGPR growth and colonization; QS gives PGPR a collective adaptive advantage in harsh natural environments.Trichosporon fermentans can be used to treat refined soybean oil wastewater (RSOW) and produce microbial lipids. Bioflocculation is an effective method to recover Trichosporon fermentans which accumulates intracellular oils from wastewater. During the flocculation, the hydrodynamic distribution and parameters in the reactor are important limiting factors of yeast flocculation performance. In a 0.25 L flocculation device, it was found that the appropriate range of turbulence kinetic energy was within 0.00065-0.00073 m2/s2, the dissipation rate was within 0.119-0.317 m2/s3, and the shear force was less than 0.433 Pa by computational fluid dynamics. In this case, the flocculation rate (Fr) of Trichosporon fermentans could reach more than 90%. The empirical formula associated Fr of Trichosporon fermentans with hydrodynamic parameters was obtained by Matlab, and improved in the enlargement of flocculation device, displaying an error of less than 3.03%. A conical draft tube airlift circulating reactor for flocculation was designed based on the empirical formula, and the Fr reached 91.