The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how ...The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how dissolved organic matter(DOM)transformation regulates the aquatic As concentrations.The present study revealed that the DOM components from the Singe Tsangpo River(STR)basin primarily consisted of protein-like components(81.30%±6.48%),with the microbially-endogenous production being a predominant source under the control of temperature and glacier-runoff recharge along the river flow path.Notably,the chemical weathering processes have significantly facilitated the enhancement of humic-like components in the river water.Besides,the groundwater DOM characteristics were predominantly influenced by the mobilization of sedimentary organic matter and the introduction of allochthonous DOM resulting from surface-water recharge.Interestingly,humic-like components facilitated As enrichment through complexation and competitive adsorption effects in both surface water and groundwater under oxidizing conditions,whichwas supported by the significant positive correlations between As and humiclike component(R^(2)=0.31/0.65,P<0.05/0.01)and the concurrent mobilization of As and humic-like components from sediment incubation experiments.Moreover,the Structural Equation Modeling analysis revealed a stronger contribution of humic-like components to the As enrichment in the groundwater compared with surface water,possibly due to the relatively strongermicrobial activity and enhanced mobilization of humic-like components in alluvial aquifers.The present study thus provided new insights into the transformation of DOM and its important role in facilitating As enrichment in the aquatic environment from alpine river basins.展开更多
In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied include...In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied included the parental strain,the POX1 deletion strain,and the POX1 overexpression strain.These strains were exposed to iso-αacid from hops at a concentration of 300 mg/L,leading to the induction of a viable but nonculturable(VBNC)state.Our results indicated that the silencing of the POX1 gene rendered brewer's yeast cells unable to withstand the high concentration of iso-αacid stress,ultimately leading to cell death.Conversely,the overexpression of POX1 accelerated the transition of yeast cells into the VBNC state compared to the parental strain.Furthermore,we evaluated the levels of reactive oxygen species(ROS),catalase(CAT)activity,superoxide dismutase(SOD)activity,glutathione reductase(GR)activity,and the m RNA expression of genes that regulate these enzymes(the stress-inducible yeast Mpv17(SYM1)gene,CTA1,SOD1,and glutathione reductase(GLR1)gene)in brewer's yeast cells at three distinct stages:normal,short-term stress,and VBNC states.Based on these findings,it can be inferred that the formation of the VBNC state in brewer's yeast is associated with the response to oxidative stress.展开更多
基金supported by the National Natural Science Foundation of China(No.42107094)Sichuan Science and Technology Program(No.2023NSFSC0806)the Geology Bureau project of Xinjiang Uygur Autonomous Region(Nos.XGMB202356 and XGMB202358).
文摘The geogenic enrichment of arsenic(As)extensively occurred in the riverine systems from the Qinghai-Tibetan Plateau under active geothermal discharge and chemical weathering conditions,while little is known about how dissolved organic matter(DOM)transformation regulates the aquatic As concentrations.The present study revealed that the DOM components from the Singe Tsangpo River(STR)basin primarily consisted of protein-like components(81.30%±6.48%),with the microbially-endogenous production being a predominant source under the control of temperature and glacier-runoff recharge along the river flow path.Notably,the chemical weathering processes have significantly facilitated the enhancement of humic-like components in the river water.Besides,the groundwater DOM characteristics were predominantly influenced by the mobilization of sedimentary organic matter and the introduction of allochthonous DOM resulting from surface-water recharge.Interestingly,humic-like components facilitated As enrichment through complexation and competitive adsorption effects in both surface water and groundwater under oxidizing conditions,whichwas supported by the significant positive correlations between As and humiclike component(R^(2)=0.31/0.65,P<0.05/0.01)and the concurrent mobilization of As and humic-like components from sediment incubation experiments.Moreover,the Structural Equation Modeling analysis revealed a stronger contribution of humic-like components to the As enrichment in the groundwater compared with surface water,possibly due to the relatively strongermicrobial activity and enhanced mobilization of humic-like components in alluvial aquifers.The present study thus provided new insights into the transformation of DOM and its important role in facilitating As enrichment in the aquatic environment from alpine river basins.
基金funded by National Natural Science Foundation of China(32272279)the Key R&D project of Shandong Province(2023CXPT007)the Key R&D project of Qingdao Science and Technology Plan(22-3-3-hygg-29-hy)。
文摘In this study,we utilized gene knockout and overexpression techniques to generate brewer's yeast strains with either a deletion or overexpression of the fatty acyl-CoA oxidase(POX1)gene.The strains studied included the parental strain,the POX1 deletion strain,and the POX1 overexpression strain.These strains were exposed to iso-αacid from hops at a concentration of 300 mg/L,leading to the induction of a viable but nonculturable(VBNC)state.Our results indicated that the silencing of the POX1 gene rendered brewer's yeast cells unable to withstand the high concentration of iso-αacid stress,ultimately leading to cell death.Conversely,the overexpression of POX1 accelerated the transition of yeast cells into the VBNC state compared to the parental strain.Furthermore,we evaluated the levels of reactive oxygen species(ROS),catalase(CAT)activity,superoxide dismutase(SOD)activity,glutathione reductase(GR)activity,and the m RNA expression of genes that regulate these enzymes(the stress-inducible yeast Mpv17(SYM1)gene,CTA1,SOD1,and glutathione reductase(GLR1)gene)in brewer's yeast cells at three distinct stages:normal,short-term stress,and VBNC states.Based on these findings,it can be inferred that the formation of the VBNC state in brewer's yeast is associated with the response to oxidative stress.
