The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In t...The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In this paper,a transcriptomic approach was used to investigate the differences in gene expression at 500.0 mg/L(Amo 500)and 100.0 mg/L(Amo 100)ammonium concentrations to reveal the mechanism of ammonia nitrogen removal from water by Pseudomonas stutzeri F2.The transcriptome data showed 1015(459 up-regulated and 556 down-regulated)differentially expressed genes with functional gene annotation related to nitrogen source metabolism,glycolysis,tricarboxylic acid cycle,extracellular polysaccharide synthesis,energy conversion and transmembrane transport,revealing the metabolic process of ammonium nitrogen conversion to biological ni-trogen in P.stutzeri F2 through assimilation.To verify the effect of ammonium transporter protein(AmtB)of cell membrane on assimilation,a P.stutzeri F2-ΔamtB mutant strain was obtained by constructing a knockout plasmid(pK18mobsacB-ΔamtB),and it was found that the growth characteristics and ammonium removal rate of the mutant strain were significantly reduced at high ammonium concentration.The carbon source components and dissolved oxygen conditions were optimized after analyzing the transcriptome data,and the ammonium removal rate was increased from 41.23%to 94.92%with 500.0 mg/L ammonium concentration.The study of P.stutzeri F2 transcript level reveals the mechanism of ammonia nitrogen influence on microbial assimilation process and improvement strategy,which provides a new strategy for the treatment of ammonia nitrogen wastewater.展开更多
The study was aimed at exploring the relationship between teaching approach and students'learning motivation.The participants were two college English teachers and their fixed group of students.The research lasted...The study was aimed at exploring the relationship between teaching approach and students'learning motivation.The participants were two college English teachers and their fixed group of students.The research lasted 16 weeks.The instruments used in the study were Attitude/Motivation Test Battery(AMTB) and classroom observation.Analyzing by the mean of the AM TB result,researchers got the popular tendencies of students'learning motivation level every four weeks.Comparing the change of students'learning motivation level and teacher participants'frequency of using the recommended teaching approach,this arti cle intends to achieve two purposes:1) Is students'learning motivation related to their teachers'teaching approach? 2) Among the approach recommended by literature,which works the best in the colleges in China?展开更多
基金supported by Foundation of Fujian Key Laboratory of Functional Aquafeed and Culture Environment Control(No.FACE20200003)111 Project(111-2-06)and Jiangsu province“Collaborative Innovation Center for Advanced Industrial Fermentation”industry development program.
文摘The biological treatment of wastewater with high concentrations of ammonia nitrogen has become a hot research issue,but there are limited reports on the mechanism of ammonia nitrogen utilization by microorganisms.In this paper,a transcriptomic approach was used to investigate the differences in gene expression at 500.0 mg/L(Amo 500)and 100.0 mg/L(Amo 100)ammonium concentrations to reveal the mechanism of ammonia nitrogen removal from water by Pseudomonas stutzeri F2.The transcriptome data showed 1015(459 up-regulated and 556 down-regulated)differentially expressed genes with functional gene annotation related to nitrogen source metabolism,glycolysis,tricarboxylic acid cycle,extracellular polysaccharide synthesis,energy conversion and transmembrane transport,revealing the metabolic process of ammonium nitrogen conversion to biological ni-trogen in P.stutzeri F2 through assimilation.To verify the effect of ammonium transporter protein(AmtB)of cell membrane on assimilation,a P.stutzeri F2-ΔamtB mutant strain was obtained by constructing a knockout plasmid(pK18mobsacB-ΔamtB),and it was found that the growth characteristics and ammonium removal rate of the mutant strain were significantly reduced at high ammonium concentration.The carbon source components and dissolved oxygen conditions were optimized after analyzing the transcriptome data,and the ammonium removal rate was increased from 41.23%to 94.92%with 500.0 mg/L ammonium concentration.The study of P.stutzeri F2 transcript level reveals the mechanism of ammonia nitrogen influence on microbial assimilation process and improvement strategy,which provides a new strategy for the treatment of ammonia nitrogen wastewater.
文摘The study was aimed at exploring the relationship between teaching approach and students'learning motivation.The participants were two college English teachers and their fixed group of students.The research lasted 16 weeks.The instruments used in the study were Attitude/Motivation Test Battery(AMTB) and classroom observation.Analyzing by the mean of the AM TB result,researchers got the popular tendencies of students'learning motivation level every four weeks.Comparing the change of students'learning motivation level and teacher participants'frequency of using the recommended teaching approach,this arti cle intends to achieve two purposes:1) Is students'learning motivation related to their teachers'teaching approach? 2) Among the approach recommended by literature,which works the best in the colleges in China?
