Many microorganisms have mechanisms that protect cells against attack from viruses.The fermentation components of Streptomyces sp.1647 exhibit potent anti-influenza A virus(IAV)activity.This strain was isolated from s...Many microorganisms have mechanisms that protect cells against attack from viruses.The fermentation components of Streptomyces sp.1647 exhibit potent anti-influenza A virus(IAV)activity.This strain was isolated from soil in southern China in the 1970s,but the chemical nature of its antiviral substance(s)has remained unknown until now.We used an integrated multi-omics strategy to identify the antiviral agents from this streptomycete.The antibiotics and Secondary Metabolite Analysis Shell(antiSMASH)analysis of its genome sequence revealed 38 biosynthetic gene clusters(BGCs)for secondary metabolites,and the target BGCs possibly responsible for the production of antiviral components were narrowed down to three BGCs by bioactivity-guided comparative transcriptomics analysis.Through bioinformatics analysis and genetic manipulation of the regulators and a biosynthetic gene,cluster 36 was identified as the BGC responsible for the biosynthesis of the antiviral compounds.Bioactivity-based molecular networking analysis of mass spectrometric data from different recombinant strains illustrated that the antiviral compounds were a class of structural analogues.Finally,18 pseudo-tetrapeptides with an internal ureido linkage,omicsynins A1–A6,B1–B6,and C1–C6,were identified and/or isolated from fermentation broth.Among them,11 compounds(omicsynins A1,A2,A6,B1–B3,B5,B6,C1,C2,and C6)are new compounds.Omicsynins B1–B4 exhibited potent antiviral activity against IAV with the 50%inhibitory concentration(IC_(50))of approximately 1μmol·L^(-1)and a selectivity index(SI)ranging from 100 to 300.Omicsynins B1–B4 also showed significant antiviral activity against human coronavirus HCoV-229E.By integrating multi-omics data,we discovered a number of novel antiviral pseudo-tetrapeptides produced by Streptomyces sp.1647,indicating that the secondary metabolites of microorganisms are a valuable source of novel antivirals.展开更多
Graphene oxide(GO)has been widely used in the modification of membranes due to its excellent properties,i.e.,huge specific surface area,good electrical conductivity,good hydrophilicity and various functional groups.Th...Graphene oxide(GO)has been widely used in the modification of membranes due to its excellent properties,i.e.,huge specific surface area,good electrical conductivity,good hydrophilicity and various functional groups.The addition of GO in membranes were proved to exhibit improved properties in water permeability,molecular selectivity,membrane fouling mitigation and contaminants decomposition.Recently,the development of laminated GO in membranes achieved both high selectivity and high water permeability,conquering the limitations of conventional polymeric or inorganic membranes.By analyzing the separation mechanisms and the performance of GO composite membranes,this review systematically summarized the applications of GO composite membranes in three highlighted areas of environmental fields:desalination,gas separation and wastewater treatment,with challenges discussed faced with GO composite membranes.展开更多
The enormous advantages of active transportation lead the transportation research focus towards enhancing the walking and biking trips.The present study explored the influential factors to the walking and biking trave...The enormous advantages of active transportation lead the transportation research focus towards enhancing the walking and biking trips.The present study explored the influential factors to the walking and biking travel frequency based on data obtained from the National Household Travel Survey California add-on survey.The study features some highlights.First,bivariate models were used to account for the common unobserved heterogeneity shared at both household and personal levels.Second,endogeneity was explicitly considered.Third,both variable importance ranking and correlation analysis are employed to determine the different features to be fed into each of the joint models.The results illustrated that the models developed with endogeneity performed better than the models without endogeneity.Four influential variables which includes mode to work by bicycle,public transit usage,count of household members,and multiple race responses,tend to have statistically significant impacts on walking and biking trips.展开更多
基金supported by the National Natural Science Foundation of China(81630089,81703398,81872780,and 81803410)the Beijing Natural Science Foundation,China(7214286)+1 种基金the Drug Innovation Major Project of China(2018ZX09711001-006-011,2018ZX09735001-002,and 2018ZX09711001-007)the CAMS Innovation Fund for Medical Sciences(2018-I2M-3-005 and 2020-I2M-2-010)。
文摘Many microorganisms have mechanisms that protect cells against attack from viruses.The fermentation components of Streptomyces sp.1647 exhibit potent anti-influenza A virus(IAV)activity.This strain was isolated from soil in southern China in the 1970s,but the chemical nature of its antiviral substance(s)has remained unknown until now.We used an integrated multi-omics strategy to identify the antiviral agents from this streptomycete.The antibiotics and Secondary Metabolite Analysis Shell(antiSMASH)analysis of its genome sequence revealed 38 biosynthetic gene clusters(BGCs)for secondary metabolites,and the target BGCs possibly responsible for the production of antiviral components were narrowed down to three BGCs by bioactivity-guided comparative transcriptomics analysis.Through bioinformatics analysis and genetic manipulation of the regulators and a biosynthetic gene,cluster 36 was identified as the BGC responsible for the biosynthesis of the antiviral compounds.Bioactivity-based molecular networking analysis of mass spectrometric data from different recombinant strains illustrated that the antiviral compounds were a class of structural analogues.Finally,18 pseudo-tetrapeptides with an internal ureido linkage,omicsynins A1–A6,B1–B6,and C1–C6,were identified and/or isolated from fermentation broth.Among them,11 compounds(omicsynins A1,A2,A6,B1–B3,B5,B6,C1,C2,and C6)are new compounds.Omicsynins B1–B4 exhibited potent antiviral activity against IAV with the 50%inhibitory concentration(IC_(50))of approximately 1μmol·L^(-1)and a selectivity index(SI)ranging from 100 to 300.Omicsynins B1–B4 also showed significant antiviral activity against human coronavirus HCoV-229E.By integrating multi-omics data,we discovered a number of novel antiviral pseudo-tetrapeptides produced by Streptomyces sp.1647,indicating that the secondary metabolites of microorganisms are a valuable source of novel antivirals.
基金supported by the National Natural Science Foundation of China(No.42107090)the Science and Technology Project of Sichuan Province,China(No.2019YJ0262)the financial support of the Basic Scientific Research Special Fund Project of Southwest Minzu University,China(No.2020NQN13).
文摘Graphene oxide(GO)has been widely used in the modification of membranes due to its excellent properties,i.e.,huge specific surface area,good electrical conductivity,good hydrophilicity and various functional groups.The addition of GO in membranes were proved to exhibit improved properties in water permeability,molecular selectivity,membrane fouling mitigation and contaminants decomposition.Recently,the development of laminated GO in membranes achieved both high selectivity and high water permeability,conquering the limitations of conventional polymeric or inorganic membranes.By analyzing the separation mechanisms and the performance of GO composite membranes,this review systematically summarized the applications of GO composite membranes in three highlighted areas of environmental fields:desalination,gas separation and wastewater treatment,with challenges discussed faced with GO composite membranes.
文摘The enormous advantages of active transportation lead the transportation research focus towards enhancing the walking and biking trips.The present study explored the influential factors to the walking and biking travel frequency based on data obtained from the National Household Travel Survey California add-on survey.The study features some highlights.First,bivariate models were used to account for the common unobserved heterogeneity shared at both household and personal levels.Second,endogeneity was explicitly considered.Third,both variable importance ranking and correlation analysis are employed to determine the different features to be fed into each of the joint models.The results illustrated that the models developed with endogeneity performed better than the models without endogeneity.Four influential variables which includes mode to work by bicycle,public transit usage,count of household members,and multiple race responses,tend to have statistically significant impacts on walking and biking trips.