Effective alleviation of Cd stress to microbial communities in mining reclamation soils by thiourea-modified biochar amendment

Reclaimed soils in mining area usually display low fertility and present Cd stress.The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility,and reduces Cd stress in soil microorganisms.However,the effect of thiourea-modified biochar(TBC)on microbial adaptability to Cd stress in mining reclamation soils is still unclear.The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contamination under TBC amendment.The results indicated that the amendment of TBC significantly enhanced(P<0.05)soil pH,the content of available phosphorus(AP),and the activities of urease and polyphenol oxidase by 1.3%,463.4%,54.4%,and 84.0%,respectively,compared to the control without amendment.The amount of toxicity characteristic leaching procedure-extracable Cd decreased(P<0.05)by 68.0%in the TBC-amended soil compared with the unamended soil.The structure of soil microbiota was reorganized and the alpha diversity index was increased in the TBC treatment.The TBC amendment increased the relative abundances of Proteobacteria,Bacteroidota,and Zoopagomycota,which were strongly associated(P<0.01)with higher soil pH and AP.Structural equation model results demonstrated that Cd immobilization was directly influenced by soil pH,AP,and urease,and indirectly affected by bacterial structure in the TBC treatment.The TBC amendment can effectively improve the structural composition of soil bacteria under Cd stress and enhance the pathways of decreasing soil Cd availability as well.The results might facilitate the development of in-situ remediation programs in Cd-contaminated soils in the future.

Boehmite-supported CuO as a catalyst for catalytic transfer hydrogenation of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan

2,5-bis(hydroxymethyl)furan(BHMF)is an important monomer of polyester.Its oxygen-containing rigid ring structure and symmetrical diol functional group establish it as an alternative to petroleum-based monomer with unique advantages for the prodution of the degradable bio-based polyester materials.Herein,we prepared a boehmite-supported copper-oxide catalyst for the selective hydrogenation of 5-hydroxymethylfurfural into BHMF via catalytic transfer hydrogenation(CTH).Further,ethanol successfully replaced conventional high-pressure hydrogen as the hydrogen donor,with up to 96.9% BHMF selectivity achieved under suitable conditions.Through characterization and factor investigations,it was noted that CuO is crucial for high BHMF selectivity.Furthermore,kinetic studies revealed a higher by-product activation energy compared to that of BHMF,which explained the influence of reaction temperature on product distribution.To establish the catalyst structure-activity correlation,a possible mechanism was proposed.The copper-oxide catalyst deactivated following CTH because ethanol reduced the CuO,which consequently decreased the active sites.Finally,calcination of the catalyst in air recovered its activity.These results will have a positive impact on hydrogenation processes in the biomass industry.

Soil microbes-mediated enzymes promoted the secondary succession in post-mining plantations on the Loess Plateau,China

The diversity of vegetation configuration is the key to ecological restoration in open-pit coal mine dump.However,the recovery outcomes of different areas with the same vegetation assemblage pattern are completely different after long-term evolution.Therefore,understanding the causes of differential vegetation recovery and the mechanism of plant succession is of great significance to the ecological restoration of mines.Three Pinus tabulaeformis plantations with similar initial site conditions and restoration measures but with different secondary succession processes were selected from the open-pit coal mine dump that has been restored for 30 years.Soil physicochemical properties,enzyme activities,vegetation and microbial features were investigated,while the structural equation models were established to explore the interactions between plants,soil and microbes.The results showed that original vegetation configuration and soil nutrient conditions were altered due to secondary succession.With the advancement of the secondary succession process,the coverage of plants increased from 34.8%to 95.5%(P<0.05),soil organic matter increased from 9.30 g kg^(-1)to 21.13 g kg^(-1)(P<0.05),and total nitrogen increased from 0.38 g kg^(-1)to 1.01 g kg^(-1)(P<0.05).The activities of soil urease and p-glucosidase were increased by 1.7-fold and 53.26%,respectively.Besides,the secondary succession also changed the soil microbial community structure and function.The relative abundance of Nitrospira genus which dominates the nitrification increased 5.2-fold.The results showed that urease andβ-glucosidase promoted the increase of vegetation diversity and biomass by promoting the accumulation of soil organic matter and nitrate nitrogen,which promoted the ecological restoration of mine dumps.

High-throughput screening and evaluation of repurposed drugs targeting the SARS-CoV-2 main protease

Dear editor,To date,a number of clinically approved drugs have been evaluated for potential to treat coronavirus disease 2019(COVID-19),such as lopinavir/ritonavir,hydroxychloroquine,cobicistat,and darunavir.Some of these drugs have been proven to be effective in vitro;however,clinical trials showed that none of these compounds led to a significant improvement in symptoms or length of hospitalization.Thus,it is essential and more reliable to start from a defined target to ide ntify can didate drugs.