In this study,a xylanase-producing Aspergillus niger strain,NS-1,was screened and isolated from agricultural and forestry wastes. Based on single-factor experiments,the effects of different carbon sources,composite ca...In this study,a xylanase-producing Aspergillus niger strain,NS-1,was screened and isolated from agricultural and forestry wastes. Based on single-factor experiments,the effects of different carbon sources,composite carbon sources,nitrogen sources,calcium carbonate concentrations,initial p H and surfactants on xylanase production by A. niger NS-1 were investigated. The results indicated that the most appropriate carbon source was corncobs; the best composite carbon source was corncobs + xylan,which was conducive to xylanase secretion; the most suitable nitrogen source was ammonium sulfate. Xylanase activity reached the highest in the medium added with 1. 5% calcium carbonate and SDS as a surfactant with an initial p H of 5. 0. This study provided the basis for the production of high-activity xylanase.展开更多
[Objective] This study aimed to investigate the optimal conditions for ultrasonic extraction of polysaccharides from Polyporus umbellatus,thus providing a reliable basis for the development and utilization of P. umbel...[Objective] This study aimed to investigate the optimal conditions for ultrasonic extraction of polysaccharides from Polyporus umbellatus,thus providing a reliable basis for the development and utilization of P. umbellatus. [Method]By single-factor experiment,the ultrasonic extraction process of polyporus polysaccharides was optimized. [Result] The optimal conditions for ultrasonic extraction of polysaccharides from P. umbellatus were: solid-liquid ratio 1∶40( g∶ml),extraction duration 60 min,extraction temperature 70 ℃,ultrasonic power 100 W. [Conclusion]Compared with conventional water extraction method,ultrasonic extraction could significantly improve the content of polyporus polysaccharides with shorter extraction duration,lower solid-liquid ratio and lower extraction temperature.展开更多
Background:There is an urgent need for developing objective,effective and convenient measurements to help clinicians accurately identify bradykinesia.The purpose of this study is to evaluate the accuracy of an objecti...Background:There is an urgent need for developing objective,effective and convenient measurements to help clinicians accurately identify bradykinesia.The purpose of this study is to evaluate the accuracy of an objective approach assessing bradykinesia in finger tapping(FT)that uses evolutionary algorithms(EAs)and explore whether it can be used to identify early stage Parkinson’s disease(PD).Methods:One hundred and seven PD,41 essential tremor(ET)patients and 49 normal controls(NC)were recruited.Participants performed a standard FT task with two electromagnetic tracking sensors attached to the thumb and index finger.Readings from the sensors were transmitted to a tablet computer and subsequently analyzed by using EAs.The output from the device(referred to as"PD-Monitor")scaled from−1 to+1(where higher scores indicate greater severity of bradykinesia).Meanwhile,the bradykinesia was rated clinically using the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale(MDS-UPDRS)FT item.Results:With an increasing MDS-UPDRS FT score,the PD-Monitor score from the same hand side increased correspondingly.PD-Monitor score correlated well with MDS-UPDRS FT score(right side:r=0.819,P=0.000;left side:r=0.783,P=0.000).Moreover,PD-Monitor scores in 97 PD patients with MDS-UPDRS FT bradykinesia and each PD subgroup(FT bradykinesia scored from 1 to 3)were all higher than that in NC.Receiver operating characteristic(ROC)curves revealed that PD-Monitor FT scores could detect different severity of bradykinesia with high accuracy(≥89.7%)in the right dominant hand.Furthermore,PD-Monitor scores could discriminate early stage PD from NC,with area under the ROC curve greater than or equal to 0.899.Additionally,ET without bradykinesia could be differentiated from PD by PD-Monitor scores.A positive correlation of PD-Monitor scores with modified Hoehn and Yahr stage was found in the left hand sides.Conclusions:Our study demonstrated that a simple to use device employing classifiers derived from EAs could not only be used to accurately measure different severity of bradykinesia in PD,but also had the potential to differentiate early stage PD from normality.展开更多
N-methyl-d-aspartic acid(NMDA),an amino acid existing in human and animal central nervous system,exerts agonist action on one of the glutamate receptor subtypes and is clinically used for treatment of diabetes,Parkin...N-methyl-d-aspartic acid(NMDA),an amino acid existing in human and animal central nervous system,exerts agonist action on one of the glutamate receptor subtypes and is clinically used for treatment of diabetes,Parkinson’s and Alzheimer’s syndrome.In this study,an enzymatic protocol for the chiral resolution of N-methyl-d,l-aspartic acid was built with a predicted N-demethylase(GenBank ID:OJV90073.1)from the genome of Chloroflexi bacterium 54-19.Through sequence alignment,the enzyme shares an identity of 32.19%to 2UZZ(PDB ID)with a conserved catalytic center.Recombinantly expressed in Bacillus subtilis WB600,the N-demethylase was characterized with optimal temperature and pH at 55℃and 7.5,and adaptive temperature and pH were 40-60℃ and 6-8.The effects of organic solvents and metal ions were investigated as well.Compared with other previously reported sarcosine oxidases,the enzyme showed a specific N-demethylation activity against N-methyl-l-aspartic acid according to the analysis by chiral liquid chromatography,LC-MS/MS and a detection by polarimeter.The results demonstrated 76%of 4.5 mM N-methyl-d,l-aspartic acid could be chirally separated by 7 mg·L^(−1) enzyme after reaction of 80 min.This work provided a foundation for mild synthesis of NMDA in industry.展开更多
基金Supported by Project of Taizhou Science and Technology Bureau(TS019)
文摘In this study,a xylanase-producing Aspergillus niger strain,NS-1,was screened and isolated from agricultural and forestry wastes. Based on single-factor experiments,the effects of different carbon sources,composite carbon sources,nitrogen sources,calcium carbonate concentrations,initial p H and surfactants on xylanase production by A. niger NS-1 were investigated. The results indicated that the most appropriate carbon source was corncobs; the best composite carbon source was corncobs + xylan,which was conducive to xylanase secretion; the most suitable nitrogen source was ammonium sulfate. Xylanase activity reached the highest in the medium added with 1. 5% calcium carbonate and SDS as a surfactant with an initial p H of 5. 0. This study provided the basis for the production of high-activity xylanase.
基金Supported by Practical Innovation Program for College Students in Jiangsu ProvinceSocial Development Project of Taizhou City(TS019)
文摘[Objective] This study aimed to investigate the optimal conditions for ultrasonic extraction of polysaccharides from Polyporus umbellatus,thus providing a reliable basis for the development and utilization of P. umbellatus. [Method]By single-factor experiment,the ultrasonic extraction process of polyporus polysaccharides was optimized. [Result] The optimal conditions for ultrasonic extraction of polysaccharides from P. umbellatus were: solid-liquid ratio 1∶40( g∶ml),extraction duration 60 min,extraction temperature 70 ℃,ultrasonic power 100 W. [Conclusion]Compared with conventional water extraction method,ultrasonic extraction could significantly improve the content of polyporus polysaccharides with shorter extraction duration,lower solid-liquid ratio and lower extraction temperature.
基金This work was supported by the National Natural Science Foundation of China(grant numbers.81430022,81771374).
文摘Background:There is an urgent need for developing objective,effective and convenient measurements to help clinicians accurately identify bradykinesia.The purpose of this study is to evaluate the accuracy of an objective approach assessing bradykinesia in finger tapping(FT)that uses evolutionary algorithms(EAs)and explore whether it can be used to identify early stage Parkinson’s disease(PD).Methods:One hundred and seven PD,41 essential tremor(ET)patients and 49 normal controls(NC)were recruited.Participants performed a standard FT task with two electromagnetic tracking sensors attached to the thumb and index finger.Readings from the sensors were transmitted to a tablet computer and subsequently analyzed by using EAs.The output from the device(referred to as"PD-Monitor")scaled from−1 to+1(where higher scores indicate greater severity of bradykinesia).Meanwhile,the bradykinesia was rated clinically using the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale(MDS-UPDRS)FT item.Results:With an increasing MDS-UPDRS FT score,the PD-Monitor score from the same hand side increased correspondingly.PD-Monitor score correlated well with MDS-UPDRS FT score(right side:r=0.819,P=0.000;left side:r=0.783,P=0.000).Moreover,PD-Monitor scores in 97 PD patients with MDS-UPDRS FT bradykinesia and each PD subgroup(FT bradykinesia scored from 1 to 3)were all higher than that in NC.Receiver operating characteristic(ROC)curves revealed that PD-Monitor FT scores could detect different severity of bradykinesia with high accuracy(≥89.7%)in the right dominant hand.Furthermore,PD-Monitor scores could discriminate early stage PD from NC,with area under the ROC curve greater than or equal to 0.899.Additionally,ET without bradykinesia could be differentiated from PD by PD-Monitor scores.A positive correlation of PD-Monitor scores with modified Hoehn and Yahr stage was found in the left hand sides.Conclusions:Our study demonstrated that a simple to use device employing classifiers derived from EAs could not only be used to accurately measure different severity of bradykinesia in PD,but also had the potential to differentiate early stage PD from normality.
基金supported by the National Key Research and Development Program of China(2018YFA0900300,2021YFC2100300).
文摘N-methyl-d-aspartic acid(NMDA),an amino acid existing in human and animal central nervous system,exerts agonist action on one of the glutamate receptor subtypes and is clinically used for treatment of diabetes,Parkinson’s and Alzheimer’s syndrome.In this study,an enzymatic protocol for the chiral resolution of N-methyl-d,l-aspartic acid was built with a predicted N-demethylase(GenBank ID:OJV90073.1)from the genome of Chloroflexi bacterium 54-19.Through sequence alignment,the enzyme shares an identity of 32.19%to 2UZZ(PDB ID)with a conserved catalytic center.Recombinantly expressed in Bacillus subtilis WB600,the N-demethylase was characterized with optimal temperature and pH at 55℃and 7.5,and adaptive temperature and pH were 40-60℃ and 6-8.The effects of organic solvents and metal ions were investigated as well.Compared with other previously reported sarcosine oxidases,the enzyme showed a specific N-demethylation activity against N-methyl-l-aspartic acid according to the analysis by chiral liquid chromatography,LC-MS/MS and a detection by polarimeter.The results demonstrated 76%of 4.5 mM N-methyl-d,l-aspartic acid could be chirally separated by 7 mg·L^(−1) enzyme after reaction of 80 min.This work provided a foundation for mild synthesis of NMDA in industry.
