Extracellular electron transfer(EET)plays a critical role in bioelectrochemical processes,allowing cou-pling between microorganisms and extracellular solid-state electrodes,metals,or other cells in energy metabolism.P...Extracellular electron transfer(EET)plays a critical role in bioelectrochemical processes,allowing cou-pling between microorganisms and extracellular solid-state electrodes,metals,or other cells in energy metabolism.Previous studies have suggested a role for outer-surface c-type cytochromes in direct metal-to-microbe electron transfer by Geobacter sulfurreducens,a model electroactive bacterium.Here,we ex-amined the possibility of other microbially produced electrical contacts by deleting the gene for PilA,the protein monomer that G.sulfurreducens assembles into electrically conductive protein nanowires(e-pili).Deleting pilA gene inhibited electron extraction from pure iron and 316L stainless steel up to 31%and 81%,respectively more than deleting the gene for the outer-surface cytochrome OmcS.This PilA-deficient phenotype,and the observation that relatively thick biofilms(21.7μm)grew on the metal surfaces at multi-cell distances from the metal surfaces suggest that e-pili contributed significantly to microbial cor-rosion via direct metal-to-microbe electron transfer.These results have implications for the fundamental understanding of electron harvest via e-pili by electroactive microbes,their uses in bioenergy production,as well as in monitoring and mitigation of metal biocorrosion.展开更多
This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins. Significant achievements in the relevant fields are summarized including the direct electron transfer between...This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins. Significant achievements in the relevant fields are summarized including the direct electron transfer between proteins and electrodes, the thermodynamic and kinetic properties, catalytic activities and activity regulation of the redox proteins. It has been demonstrated that the electrochemical technique is an effective tool for protein studies, especially for probing into the electron transfer and interfacial behavior of redox proteins.展开更多
The liquid-liquid extraction method using reverse micelles can simultaneously extract lipid and protein of oilseeds,which have become increasingly popular in recent years.However,there are few studies on mass transfer...The liquid-liquid extraction method using reverse micelles can simultaneously extract lipid and protein of oilseeds,which have become increasingly popular in recent years.However,there are few studies on mass transfer processes and models,which are helpful to better control the extraction process of oils and proteins.In this paper,mass transfer process of peanut protein extracted by bis(2-ethylhexyl)sodium sulfosuccinate(AOT)/isooctane reverse micelles was investigated.The effects of stirring speed(0,70,140,and 210 r/min),temperature of extraction(30,35,40,45,and 50℃),peanut flour particle size(0.355,0.450,0.600,and 0.900 mm)and solidliquid ratio(0.010,0.0125,0.015,0.0175,and 0.020 g/mL)on extraction rate were examined.The results showed that extraction rate increased with temperature rising,particle size reduction as well as solid-liquid ratio increase respectively,while little effect of stirring speed(P>0.05)was observed.The apparent activation energy of extraction process was calculated as 10.02 kJ/mol and Arrhenius constant(A)was 1.91 by Arrhenius equation.There was a linear relationship between reaction rate constant and the square of the inverse of initial particle radius(1/r_(0)^(2))(P<0.05).This phenomenon and this shrinking core model were anastomosed.In brief,the extraction process was controlled by the diffusion of protein from the virgin zone interface of particle through the reacted zone and it was in line with the first order reaction.Mass transfer kinetics of peanut protein extracted by reverse micelles was established and it was verified by experimental results.The results provide an important theoretical guidance for industrial production of peanut protein separation and purification.展开更多
High salinity inhibits microbial activity in the bioremediation of saline wastewater.To alleviate osmotic stress,glycine betaine(GB),an osmoprotectant,is added to enhance the secretion of extracellular polymeric subst...High salinity inhibits microbial activity in the bioremediation of saline wastewater.To alleviate osmotic stress,glycine betaine(GB),an osmoprotectant,is added to enhance the secretion of extracellular polymeric substances(EPS).These EPS are pivotal in withstanding environmental stressors,yet the intricate interplay between GB supplementation and microbial responses through EPS modificationsdencompassing composition,molecular architecture,and electrochemical featuresdremains elusive in hypersaline conditions.Here we show microbial strategies for salinity endurance by investigating the impact of GB on the dynamic alterations of EPS properties.Our findings reveal that GB supplementation at 3.5%salinity elevates the total EPS(T-EPS)content from 12.50±0.05 to 24.58±0.96 mg per g dry cell weight.The observed shift in zeta potential from-28.95 to-6.25 mV at 0%and 3.5%salinity,respectively,with GB treatment,indicates a reduction in electrostatic repulsion and compaction.Notably,the EPS protein secondary structure transition from b-sheet to a-helix,with GB addition,signifies a more compact protein configuration,less susceptible to salinity fluctuations.Electrochemical analyses,including cyclic voltammetry(CV)and differential pulse voltammetry(DPV),reveal GB's role in promoting the release of exogenous electron shuttles,such as flavins and c-type cytochromes(c-Cyts).The enhancement in DPV peak areas(Q_(DPV))with GB addition implies an increase in available extracellular electron transfer sites.This investigation advances our comprehension of microbial adaptation mechanisms to salinity through EPS modifications facilitated by GB in saline habitats.展开更多
Cuscuta species(dodders)are holoparasites that totally rely on host plants to survive.Although various mobile proteins have been identified to travel within a plant,whether and to what extent protein transfer between ...Cuscuta species(dodders)are holoparasites that totally rely on host plants to survive.Although various mobile proteins have been identified to travel within a plant,whether and to what extent protein transfer between Cuscuta and host plants remain unclear.We found that hundreds to more than 1500 proteins were transferred between Cuscuta and the host plants Arabidopsis and soybean,and hundreds of interplant mobile proteins were even detected in the seeds of Cuscuta and the host soybean.Different hosts bridge-connected by dodder were also found to exchange hundreds of proteins.Quantitatively,the mobile proteins represent a few to more than 10%of the proteomes of foreign plants.Using Arabidopsis plants expressing different reporter proteins,we further showed that these reporter proteins could travel between plants and,importantly,retained their activity in the foreign plants.Comparative analysis between the interplant mobile proteins and mRNAs indicated that the majority of mobile proteins were not de novo synthesized from the translocated mRNAs,but bona fide mobile proteins.We propose that large-scale inter-plant protein translocation may play an important role in the interactions between host plants and dodder and even among the dodder bridge-connected hosts.展开更多
Major light-harvesting complex of photosystemⅡ(LHCⅡ)plays a dual role in light-harvesting and excited energy dissipation to protect photodamage from excess energy.The regulatory switch is induced by increased acidit...Major light-harvesting complex of photosystemⅡ(LHCⅡ)plays a dual role in light-harvesting and excited energy dissipation to protect photodamage from excess energy.The regulatory switch is induced by increased acidity,temperature or both.However,the molecular origin of the protein dynamics at the atomic level is still unknown.We carried out temperature-jump time-resolved infrared spectroscopy and molecular dynamics simulations to determine the energy quenching dynamics and conformational changes of LHCⅡtrimers.We found that the spontaneous formation of a pair of localα-helices from the 310-helix E/loop and the C-terminal coil of the neighboring monomer,in response to the increased environmental temperature and/or acidity,induces a scissoring motion of transmembrane helices A and B,shifting the conformational equilibrium to a more open state,with an increased angle between the associated carotenoids.The dynamical and allosteric conformation change leads to close contacts between carotenoid lutein 1 and chlorophyll pigment 612,facilitating the fluorescence quenching.Based on these results,we suggest a unified mechanism by which the LHCⅡtrimer controls the dissipation of excess excited energy in response to increased temperature and acidity,as an intrinsic result of intense sun light in plant photosynthesis.展开更多
基金supported by the National Natu-ral Science Foundation of China(Nos.U2006219 and 52101078)China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202120)+2 种基金the National Key Research and Development Pro-gram of China(No.2020YFA0907300)the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(Nos.N2102009 and N2002019)the Liaoning Revitaliza-tion Talents Program(No.XLYC1907158).
文摘Extracellular electron transfer(EET)plays a critical role in bioelectrochemical processes,allowing cou-pling between microorganisms and extracellular solid-state electrodes,metals,or other cells in energy metabolism.Previous studies have suggested a role for outer-surface c-type cytochromes in direct metal-to-microbe electron transfer by Geobacter sulfurreducens,a model electroactive bacterium.Here,we ex-amined the possibility of other microbially produced electrical contacts by deleting the gene for PilA,the protein monomer that G.sulfurreducens assembles into electrically conductive protein nanowires(e-pili).Deleting pilA gene inhibited electron extraction from pure iron and 316L stainless steel up to 31%and 81%,respectively more than deleting the gene for the outer-surface cytochrome OmcS.This PilA-deficient phenotype,and the observation that relatively thick biofilms(21.7μm)grew on the metal surfaces at multi-cell distances from the metal surfaces suggest that e-pili contributed significantly to microbial cor-rosion via direct metal-to-microbe electron transfer.These results have implications for the fundamental understanding of electron harvest via e-pili by electroactive microbes,their uses in bioenergy production,as well as in monitoring and mitigation of metal biocorrosion.
基金support from the National Natural Science Foundation of China (Grant Nos. 90406005 & 20575028) the Program for New Century Excellent Talents in University,the Chinese Ministry of Education (Grant No. NCET-04-0452)
文摘This paper reviews the recent progress in the electron transfer and interfacial behavior of redox proteins. Significant achievements in the relevant fields are summarized including the direct electron transfer between proteins and electrodes, the thermodynamic and kinetic properties, catalytic activities and activity regulation of the redox proteins. It has been demonstrated that the electrochemical technique is an effective tool for protein studies, especially for probing into the electron transfer and interfacial behavior of redox proteins.
基金This study was supported by the National Natural Science Foundation of China(No.U21A20270 and 32202079)Postdoctoral Science and Technology Project of Henan,Grant No.HN2022046+2 种基金Science and Technology Project of Henan Province(232103810064)the Innovative Funds Plan of Henan University of Technology(2021ZKCJ03)the Key Scientific Research Projects of Colleges and Universities of Henan(23A550012).
文摘The liquid-liquid extraction method using reverse micelles can simultaneously extract lipid and protein of oilseeds,which have become increasingly popular in recent years.However,there are few studies on mass transfer processes and models,which are helpful to better control the extraction process of oils and proteins.In this paper,mass transfer process of peanut protein extracted by bis(2-ethylhexyl)sodium sulfosuccinate(AOT)/isooctane reverse micelles was investigated.The effects of stirring speed(0,70,140,and 210 r/min),temperature of extraction(30,35,40,45,and 50℃),peanut flour particle size(0.355,0.450,0.600,and 0.900 mm)and solidliquid ratio(0.010,0.0125,0.015,0.0175,and 0.020 g/mL)on extraction rate were examined.The results showed that extraction rate increased with temperature rising,particle size reduction as well as solid-liquid ratio increase respectively,while little effect of stirring speed(P>0.05)was observed.The apparent activation energy of extraction process was calculated as 10.02 kJ/mol and Arrhenius constant(A)was 1.91 by Arrhenius equation.There was a linear relationship between reaction rate constant and the square of the inverse of initial particle radius(1/r_(0)^(2))(P<0.05).This phenomenon and this shrinking core model were anastomosed.In brief,the extraction process was controlled by the diffusion of protein from the virgin zone interface of particle through the reacted zone and it was in line with the first order reaction.Mass transfer kinetics of peanut protein extracted by reverse micelles was established and it was verified by experimental results.The results provide an important theoretical guidance for industrial production of peanut protein separation and purification.
基金financed by the National Key Research and Development Program of China(No.2021YFA1201704)the National Natural Science Foundation of China(No.52170084)the Natural Science Foundation of Jiangsu Province(BK20211574).
文摘High salinity inhibits microbial activity in the bioremediation of saline wastewater.To alleviate osmotic stress,glycine betaine(GB),an osmoprotectant,is added to enhance the secretion of extracellular polymeric substances(EPS).These EPS are pivotal in withstanding environmental stressors,yet the intricate interplay between GB supplementation and microbial responses through EPS modificationsdencompassing composition,molecular architecture,and electrochemical featuresdremains elusive in hypersaline conditions.Here we show microbial strategies for salinity endurance by investigating the impact of GB on the dynamic alterations of EPS properties.Our findings reveal that GB supplementation at 3.5%salinity elevates the total EPS(T-EPS)content from 12.50±0.05 to 24.58±0.96 mg per g dry cell weight.The observed shift in zeta potential from-28.95 to-6.25 mV at 0%and 3.5%salinity,respectively,with GB treatment,indicates a reduction in electrostatic repulsion and compaction.Notably,the EPS protein secondary structure transition from b-sheet to a-helix,with GB addition,signifies a more compact protein configuration,less susceptible to salinity fluctuations.Electrochemical analyses,including cyclic voltammetry(CV)and differential pulse voltammetry(DPV),reveal GB's role in promoting the release of exogenous electron shuttles,such as flavins and c-type cytochromes(c-Cyts).The enhancement in DPV peak areas(Q_(DPV))with GB addition implies an increase in available extracellular electron transfer sites.This investigation advances our comprehension of microbial adaptation mechanisms to salinity through EPS modifications facilitated by GB in saline habitats.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11050200)the National Science Foundation of China(31970274)+1 种基金CAS Youth Innovation Prom otion Association(2018426)the International Partnership Program of the Chinese Academy of Sciences(151853KYSB20170025).
文摘Cuscuta species(dodders)are holoparasites that totally rely on host plants to survive.Although various mobile proteins have been identified to travel within a plant,whether and to what extent protein transfer between Cuscuta and host plants remain unclear.We found that hundreds to more than 1500 proteins were transferred between Cuscuta and the host plants Arabidopsis and soybean,and hundreds of interplant mobile proteins were even detected in the seeds of Cuscuta and the host soybean.Different hosts bridge-connected by dodder were also found to exchange hundreds of proteins.Quantitatively,the mobile proteins represent a few to more than 10%of the proteomes of foreign plants.Using Arabidopsis plants expressing different reporter proteins,we further showed that these reporter proteins could travel between plants and,importantly,retained their activity in the foreign plants.Comparative analysis between the interplant mobile proteins and mRNAs indicated that the majority of mobile proteins were not de novo synthesized from the translocated mRNAs,but bona fide mobile proteins.We propose that large-scale inter-plant protein translocation may play an important role in the interactions between host plants and dodder and even among the dodder bridge-connected hosts.
基金supported by the National Natural Science Foundation of China(21433014,11721404,21533003)the Ministry of Science and Technology(2017YFB0203400)+1 种基金Chinese Academy of Sciences Innovation Program(KJCX2-YW-W25)the National Institutes of Health(GM46736,GM64742)。
文摘Major light-harvesting complex of photosystemⅡ(LHCⅡ)plays a dual role in light-harvesting and excited energy dissipation to protect photodamage from excess energy.The regulatory switch is induced by increased acidity,temperature or both.However,the molecular origin of the protein dynamics at the atomic level is still unknown.We carried out temperature-jump time-resolved infrared spectroscopy and molecular dynamics simulations to determine the energy quenching dynamics and conformational changes of LHCⅡtrimers.We found that the spontaneous formation of a pair of localα-helices from the 310-helix E/loop and the C-terminal coil of the neighboring monomer,in response to the increased environmental temperature and/or acidity,induces a scissoring motion of transmembrane helices A and B,shifting the conformational equilibrium to a more open state,with an increased angle between the associated carotenoids.The dynamical and allosteric conformation change leads to close contacts between carotenoid lutein 1 and chlorophyll pigment 612,facilitating the fluorescence quenching.Based on these results,we suggest a unified mechanism by which the LHCⅡtrimer controls the dissipation of excess excited energy in response to increased temperature and acidity,as an intrinsic result of intense sun light in plant photosynthesis.
