Dear Editor,The COVID-19 pandemic caused by SARS-CoV-2 has led to acute respiratory distress syndrome(ARDS)with a high rate of death.An excessive inflammatory response,caused by virus infection,is associated with seve...Dear Editor,The COVID-19 pandemic caused by SARS-CoV-2 has led to acute respiratory distress syndrome(ARDS)with a high rate of death.An excessive inflammatory response,caused by virus infection,is associated with severe clinical manifestations that may lead to death of patients.1 Therefore,the blockage of virus replication and suppression of hyper-inflammatory response are beneficial for COVID-19 treatment.However,the drug targeting both virus and hyper-inflammation,as far as we know,is not available yet.展开更多
Cancer is a leading cause of death in China with an estimation of nearly 2 million deaths every year(Chen and Fu,2011b).Matter of a public health importance in China and worldwide,the scientific community is still facing
Polycyclic musks are widely used for cos- metics and other personal care and household cleaning products. The occurrence and removal of two representa- tive polycyclic musks, galaxolide （HHCB） and tonalide （AHTN） ...Polycyclic musks are widely used for cos- metics and other personal care and household cleaning products. The occurrence and removal of two representa- tive polycyclic musks, galaxolide （HHCB） and tonalide （AHTN） were investigated in three different processes of two sewage treatment plants （STPs） in Xi＇an, China. The samples were preconcentrated by solid phase extraction procedure and analyzed using a gas chromatography mass spectrometry （GC/MS） by a modified procedure. The HHCB was in the range of 82.8 to 182.5 ng.L1 in the influents and 22.6 to 103.9ng.L-1 in the effluents. The AHTN ranged from 11.0 to 19.3 ng. L-1 in the influents and 2.2 to 8.8 ng. I_~1 in the effluents. The removal efficiency of the two musks varied in the ranges of 43.1%-70.4% for HHCB and 54.2%-84.4% for AHTN. Concentrations of the two musks in aqueous phase of three processes slightly increased along the primary process, and significantly removed during the biologic treatment processes, revealing that the selected musks could be remarkably removed in varied activated sludge processes. Advanced processes of activated sludge did not show a significant superiority on selected musk removal compared to the conventional process. The selected musk removal mainly resulted from the adsorption function of activated sludge. There was no significant change of HHCB/AHTN ratios along the treatment flow, indicating that each sewage treatment structure had a similar removal efficiency for the two musks.展开更多
L-DOPA is a major drug for the treatment of Parkinson’s disease,and microbial enzymatic synthesis is an essential way for its industrial production.The expression of tyrosine phenol-lyase(TPL)derived from Erwinia her...L-DOPA is a major drug for the treatment of Parkinson’s disease,and microbial enzymatic synthesis is an essential way for its industrial production.The expression of tyrosine phenol-lyase(TPL)derived from Erwinia herbicola under six diferent constitutive promoters in Escherichia coli was studied.The recombinant strain 5 can express TPL well with growth.The optimal medium composition of this strain was as follows:tryptone 18 g/L,yeast extract 28 g/L,glycerol 10 g/L.After the cell culture is completed,the collected cells were used to catalyze the production of L-DOPA,and the concentration can reach 67.9 g/L.展开更多
l-Lactate dehydrogenases can reduce alpha-keto carboxylic acids asymmetrically and generally have a broad substrate spectrum.l-Lactate dehydrogenase gene(LF-l-LDH0845)with reducing activity towards 3,4-dihydroxyphenyl...l-Lactate dehydrogenases can reduce alpha-keto carboxylic acids asymmetrically and generally have a broad substrate spectrum.l-Lactate dehydrogenase gene(LF-l-LDH0845)with reducing activity towards 3,4-dihydroxyphenylpyruvate and phenylpyruvate was obtained from Lactobacillus fermentum JN248.To change the substrate specificity of LDH0845 and improve its catalytic activity towards large substrates,site-directed mutation of Tyr221 was performed by analyzing the amino acids in the active center.Kinetic parameters show that the kcat values of Y221F mutant on 3,4-dihydroxyphenylpyruvate,4-methyl-2-oxopentanoate,and glyoxylate are 1.21 s^(−1),1.35 s^(−1),and 0.72 s^(−1),respectively,which are 420%,150%and 130%of the wild-type LDH0845.This study shows that the mutations of Y221 can significantly change the substrate specificity of LDH0845,making it become a potential tool enzyme for the reduction of alpha-keto carboxylic acids with large functional groups.展开更多
基金supported by National Key R&D Program of China[2018YFA0107000]National Natural Science Foundation of China Grants(82025014,31900516,8201101103,81870506,and 21701194)+3 种基金Guangzhou Municipal People's Livelihood Science and technology plan[201803010108]Fundamental Research Funds for Central Universities(20lgpy119,19lgpy177)the China Postdoctoral Science Foundation(2019M653170)Shenzhen Key Medical Discipline Construction Fund(SZXK002)and grant from COVID-19 emergency tackling research project of Shandong University(Grant No.2020XGB03 to P.H.W).
文摘Dear Editor,The COVID-19 pandemic caused by SARS-CoV-2 has led to acute respiratory distress syndrome(ARDS)with a high rate of death.An excessive inflammatory response,caused by virus infection,is associated with severe clinical manifestations that may lead to death of patients.1 Therefore,the blockage of virus replication and suppression of hyper-inflammatory response are beneficial for COVID-19 treatment.However,the drug targeting both virus and hyper-inflammation,as far as we know,is not available yet.
文摘Cancer is a leading cause of death in China with an estimation of nearly 2 million deaths every year(Chen and Fu,2011b).Matter of a public health importance in China and worldwide,the scientific community is still facing
文摘Polycyclic musks are widely used for cos- metics and other personal care and household cleaning products. The occurrence and removal of two representa- tive polycyclic musks, galaxolide （HHCB） and tonalide （AHTN） were investigated in three different processes of two sewage treatment plants （STPs） in Xi＇an, China. The samples were preconcentrated by solid phase extraction procedure and analyzed using a gas chromatography mass spectrometry （GC/MS） by a modified procedure. The HHCB was in the range of 82.8 to 182.5 ng.L1 in the influents and 22.6 to 103.9ng.L-1 in the effluents. The AHTN ranged from 11.0 to 19.3 ng. L-1 in the influents and 2.2 to 8.8 ng. I_~1 in the effluents. The removal efficiency of the two musks varied in the ranges of 43.1%-70.4% for HHCB and 54.2%-84.4% for AHTN. Concentrations of the two musks in aqueous phase of three processes slightly increased along the primary process, and significantly removed during the biologic treatment processes, revealing that the selected musks could be remarkably removed in varied activated sludge processes. Advanced processes of activated sludge did not show a significant superiority on selected musk removal compared to the conventional process. The selected musk removal mainly resulted from the adsorption function of activated sludge. There was no significant change of HHCB/AHTN ratios along the treatment flow, indicating that each sewage treatment structure had a similar removal efficiency for the two musks.
基金We thank the National Key Scientifc Instrument and Equipment Development Project of China(2013YQ17052504)the Program for Changjiang Scholars and Innovative Research Team in the University of Ministry of Education of China(IRT_15R55)+1 种基金the seventh group of Hundred-Talent Program of Shanxi Province(2015)The Key Project of Research and Development Plan of Shaanxi(2017ZDCXLSF-01-02-01)for fnancial support.
文摘L-DOPA is a major drug for the treatment of Parkinson’s disease,and microbial enzymatic synthesis is an essential way for its industrial production.The expression of tyrosine phenol-lyase(TPL)derived from Erwinia herbicola under six diferent constitutive promoters in Escherichia coli was studied.The recombinant strain 5 can express TPL well with growth.The optimal medium composition of this strain was as follows:tryptone 18 g/L,yeast extract 28 g/L,glycerol 10 g/L.After the cell culture is completed,the collected cells were used to catalyze the production of L-DOPA,and the concentration can reach 67.9 g/L.
基金the National Key Scientific Instrument and Equipment Development Project of China(2013YQ17052504)the Program for Changjiang Scholars and Innovative Research Team in the University of Ministry of Education of China(IRT_15R55)+1 种基金the Natural Science Foundation of Shaanxi province(2019JQ-725)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX19_1841,KYCX19_1842)for financial support.
文摘l-Lactate dehydrogenases can reduce alpha-keto carboxylic acids asymmetrically and generally have a broad substrate spectrum.l-Lactate dehydrogenase gene(LF-l-LDH0845)with reducing activity towards 3,4-dihydroxyphenylpyruvate and phenylpyruvate was obtained from Lactobacillus fermentum JN248.To change the substrate specificity of LDH0845 and improve its catalytic activity towards large substrates,site-directed mutation of Tyr221 was performed by analyzing the amino acids in the active center.Kinetic parameters show that the kcat values of Y221F mutant on 3,4-dihydroxyphenylpyruvate,4-methyl-2-oxopentanoate,and glyoxylate are 1.21 s^(−1),1.35 s^(−1),and 0.72 s^(−1),respectively,which are 420%,150%and 130%of the wild-type LDH0845.This study shows that the mutations of Y221 can significantly change the substrate specificity of LDH0845,making it become a potential tool enzyme for the reduction of alpha-keto carboxylic acids with large functional groups.
