Polyhydroxyalkanoates(PHA)have been produced by some bacteria as bioplastics for many years.Yet their commercialization is still on the way.A few issues are related to the difficulty of PHA commercialization:namely,hi...Polyhydroxyalkanoates(PHA)have been produced by some bacteria as bioplastics for many years.Yet their commercialization is still on the way.A few issues are related to the difficulty of PHA commercialization:namely,high cost and instabilities on molecular weights(Mw)and structures,thus instability on thermo-mechanical properties.The high cost is the result of complicated bioprocessing associated with sterilization,low conversion of carbon substrates to PHA products,and slow growth of microorganisms as well as difficulty of downstream separation.Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles,developments of engineering approaches for the extremophiles,increase on carbon substrates to PHA conversion and controlling Mw of PHA.The concept proof studies could still be conducted on E.coli or Pseudomonas spp.that are easily used for molecular manipulations.In this review,we will use E.coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.展开更多
Sergei Winogradsky illuminated revolutionary concepts and produced a tool to visualize complex microbial communities and their metabolisms over time:columns displaying aquatic consortia with variety of niches.We worke...Sergei Winogradsky illuminated revolutionary concepts and produced a tool to visualize complex microbial communities and their metabolisms over time:columns displaying aquatic consortia with variety of niches.We worked with museums in Utah to create Winogradsky columns that would highlight aesthetic properties of the Great Salt Lake(GSL)ecosystem,which has a salinity gradient from the freshwater wetlands to salt saturation.One column,constructed using haloarchaea-rich hypersaline brine and oolitic sand of the lake’s north arm,was enriched with nutrients,and resulted in the desired pink hue over time.After a seven-year maturation period,we examined the microbial taxa present in the water through 16 S/18 S rRNA and Internal Transcribed Spacer(ITS)gene sequencing.A pigment analysis revealed an abundance of bacteriochlorophyll a.The presence of this pigment coupled with the DNA sequencing results,suggest that the haloarchaea that dominate the GSL brine,were not responsible for the pink coloration,but instead Gammaproteobacteria,especially Halorhodospira species.Among the eukaryotes,the lack of phytoplankton and the abundance of fungi were noteworthy observations.These data likely relate to the reduction of oxygen in a non-aerated sealed system over time.Our second exhibit had the goal of educating museum goers about the varying salinities of Great Salt Lake.Here we employed three distinct columns of water and sediment from this salinity gradient.Observations of these columns overtime gave us information about invertebrate communities in addition to the microbial consortia.Both installations taught us about comparing an artificial environment in a museum setting to the natural ecosystem.Taken together,we present the data collected and lessons learned from using Winogradsky columns in public spaces for teaching about an important saline lake.展开更多
1 Introduction It is the focus of geology and biology that the creature preserved in the geological history and the organic evolution.The creature preserved in geological history by these things:sedimentary,frozen ear...1 Introduction It is the focus of geology and biology that the creature preserved in the geological history and the organic evolution.The creature preserved in geological history by these things:sedimentary,frozen earth,chrysophoron and evaporation salt.Evaporation salt can preserve the microbe展开更多
[Objective] This study aimed to screen an Na＋/H＋ antiporter gene from the halophiles colonizing in the Dagong Ancient Brine Well in Zigong City, China, and then analyze the gene structure and properties of the prote...[Objective] This study aimed to screen an Na＋/H＋ antiporter gene from the halophiles colonizing in the Dagong Ancient Brine Well in Zigong City, China, and then analyze the gene structure and properties of the protein encoded by this gene. [Method] Metagenomic DNA libraries of halophiles from the Dagong Ancient Brine Well were used for screening genes with Na＋/H＋ antiporter activity in antiporter-defi- cient E. coil KNabc strain by functional complementation. Then the start codon, stop codon, ORF, -35 region, -10 region and SD sequence of Na~/H＋ antiporter gene, as well as the molecular weight, isoelectric point, hydrophobic region, transmembrane domain, phyletic evolution and salt resistance of protein encoded by the gene were investigated. [Result] A new Na＋/H＋ antiporter gene m-nha was obtained, which ,ren- dered the antiporter-negative mutant E. coil KNabc cells with both the resistance to Na＋ and the ability to grow under alkaline conditions. [Conclusion] The structure and amino acid sequence of M-Nha was different from the previously reported Na＋/H~ antiporters, and the m-nha gene disclosed from the Dagong Ancient Brine Well was identified as a novel Na＋/H＋ antiporter gene. This study was significant not only in helping us understand the salt tolerance of halophiles in ancient brine wells and develop and utilize the genes resource, but also in exploring new salt-tolerant genes.展开更多
1 Introduction The study of floating bath began in 1914,by Dor.John C.Lily,the expert of medical and neurology.She has done different kinds of floating experiments to study about the origin of consciousness and the re...1 Introduction The study of floating bath began in 1914,by Dor.John C.Lily,the expert of medical and neurology.She has done different kinds of floating experiments to study about the origin of consciousness and the relationship with brain.Previous research showed that the effect of floating展开更多
基金This research was financially supported by a grant from Ministry of Sciences and Technology(Grant No.2016YFB0302504)grants from National Natural Science Foundation of China(Grant No.31430003)Tsinghua President Fund also supported this project(Grant No.2015THZ10).
文摘Polyhydroxyalkanoates(PHA)have been produced by some bacteria as bioplastics for many years.Yet their commercialization is still on the way.A few issues are related to the difficulty of PHA commercialization:namely,high cost and instabilities on molecular weights(Mw)and structures,thus instability on thermo-mechanical properties.The high cost is the result of complicated bioprocessing associated with sterilization,low conversion of carbon substrates to PHA products,and slow growth of microorganisms as well as difficulty of downstream separation.Future engineering on PHA producing microorganisms should be focused on contamination resistant bacteria especially extremophiles,developments of engineering approaches for the extremophiles,increase on carbon substrates to PHA conversion and controlling Mw of PHA.The concept proof studies could still be conducted on E.coli or Pseudomonas spp.that are easily used for molecular manipulations.In this review,we will use E.coli and halophiles as examples to show how to engineer bacteria for enhanced PHA biosynthesis and for increasing PHA competitiveness.
基金Supported by the NASA Utah Space Grant Consortium and Preston Chiaro。
文摘Sergei Winogradsky illuminated revolutionary concepts and produced a tool to visualize complex microbial communities and their metabolisms over time:columns displaying aquatic consortia with variety of niches.We worked with museums in Utah to create Winogradsky columns that would highlight aesthetic properties of the Great Salt Lake(GSL)ecosystem,which has a salinity gradient from the freshwater wetlands to salt saturation.One column,constructed using haloarchaea-rich hypersaline brine and oolitic sand of the lake’s north arm,was enriched with nutrients,and resulted in the desired pink hue over time.After a seven-year maturation period,we examined the microbial taxa present in the water through 16 S/18 S rRNA and Internal Transcribed Spacer(ITS)gene sequencing.A pigment analysis revealed an abundance of bacteriochlorophyll a.The presence of this pigment coupled with the DNA sequencing results,suggest that the haloarchaea that dominate the GSL brine,were not responsible for the pink coloration,but instead Gammaproteobacteria,especially Halorhodospira species.Among the eukaryotes,the lack of phytoplankton and the abundance of fungi were noteworthy observations.These data likely relate to the reduction of oxygen in a non-aerated sealed system over time.Our second exhibit had the goal of educating museum goers about the varying salinities of Great Salt Lake.Here we employed three distinct columns of water and sediment from this salinity gradient.Observations of these columns overtime gave us information about invertebrate communities in addition to the microbial consortia.Both installations taught us about comparing an artificial environment in a museum setting to the natural ecosystem.Taken together,we present the data collected and lessons learned from using Winogradsky columns in public spaces for teaching about an important saline lake.
基金supported by the China Geological Survey project (12120113019100)the project the Public Welfare Major Program from MLR(201011001-4)
文摘1 Introduction It is the focus of geology and biology that the creature preserved in the geological history and the organic evolution.The creature preserved in geological history by these things:sedimentary,frozen earth,chrysophoron and evaporation salt.Evaporation salt can preserve the microbe
基金Supported by Chunhui Plan of Ministry of Education(Z2010101)Open Fund of Food Biotechnology Key Laboratory of Sichuan Province(SZJJ2009-014)Scientific Research Foundation of Xihua University(000022)~~
文摘[Objective] This study aimed to screen an Na＋/H＋ antiporter gene from the halophiles colonizing in the Dagong Ancient Brine Well in Zigong City, China, and then analyze the gene structure and properties of the protein encoded by this gene. [Method] Metagenomic DNA libraries of halophiles from the Dagong Ancient Brine Well were used for screening genes with Na＋/H＋ antiporter activity in antiporter-defi- cient E. coil KNabc strain by functional complementation. Then the start codon, stop codon, ORF, -35 region, -10 region and SD sequence of Na~/H＋ antiporter gene, as well as the molecular weight, isoelectric point, hydrophobic region, transmembrane domain, phyletic evolution and salt resistance of protein encoded by the gene were investigated. [Result] A new Na＋/H＋ antiporter gene m-nha was obtained, which ,ren- dered the antiporter-negative mutant E. coil KNabc cells with both the resistance to Na＋ and the ability to grow under alkaline conditions. [Conclusion] The structure and amino acid sequence of M-Nha was different from the previously reported Na＋/H~ antiporters, and the m-nha gene disclosed from the Dagong Ancient Brine Well was identified as a novel Na＋/H＋ antiporter gene. This study was significant not only in helping us understand the salt tolerance of halophiles in ancient brine wells and develop and utilize the genes resource, but also in exploring new salt-tolerant genes.
基金supported by Natioal Natural Science Foundation of China ( 40772065 )the Open project from the key lab of saline lake resources and environments, MLR ( 2010-SYS-06 )
文摘1 Introduction The study of floating bath began in 1914,by Dor.John C.Lily,the expert of medical and neurology.She has done different kinds of floating experiments to study about the origin of consciousness and the relationship with brain.Previous research showed that the effect of floating
