Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integ...Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integrate and/or respond to sensory cues. In contrast, zebrafish(Danio rerio) possess an endogenous capacity to regenerate lost neurons. Here, we will focus on the processes that lead to neuronal regeneration in the zebrafish retina. Dying retinal neurons release a damage signal, tumor necrosis factor α, which induces the resident radial glia, the Müller glia, to reprogram and re-enter the cell cycle. The Müller glia divide asymmetrically to produce a Müller glia that exits the cell cycle and a neuronal progenitor cell. The arising neuronal progenitor cells undergo several rounds of cell divisions before they migrate to the site of damage to differentiate into the neuronal cell types that were lost. Molecular and immunohistochemical studies have predominantly provided insight into the mechanisms that regulate retinal regeneration. However, many processes during retinal regeneration are dynamic and require live-cell imaging to fully discern the underlying mechanisms. Recently, a multiphoton imaging approach of adult zebrafish retinal cultures was developed. We will discuss the use of live-cell imaging, the currently available tools and those that need to be developed to advance our knowledge on major open questions in the field of retinal regeneration.展开更多
Cells in the body are exposed to physiological and pathophysiological stimuli that encompass both chemical and mechanical factors,which coordinately modulate cellular functions. Compared to the large amount of informa...Cells in the body are exposed to physiological and pathophysiological stimuli that encompass both chemical and mechanical factors,which coordinately modulate cellular functions. Compared to the large amount of information on cellular re-展开更多
To determine the effects of microwave radiation at the molecular level as well as on the germination,growth and morphology of dry spores at the single-cell level.Dry Bacillus aryabhattai MCCC 1K02966 spores were micro...To determine the effects of microwave radiation at the molecular level as well as on the germination,growth and morphology of dry spores at the single-cell level.Dry Bacillus aryabhattai MCCC 1K02966 spores were microwave-treated at different powers and characterized using single-cell optical technology.As determined by laser tweezers Raman spectroscopy,the Ca^(2+)-dipicolinic acid content increased and nucleic acid denaturation occurred in response to microwave treatment.Livecell microscopy revealed that the germination and growth rates decreased as the microwave power increased.With respect to morphology,atomic force microscopy(AFM)demonstrated that spores became wrinkled and rough after microwave treatment.Furthermore,spores became smaller as the microwave power increased.Microwave treatment can damage DNA,and high-power microwaves can inhibit the germination of spores and reduce spore volumes.These results provide a new perspective on the responses of living single cells to microwave radiation and demonstrate the application of various new techniques for analyses of microorganisms at the single-cell level.展开更多
The dynamic behavior of organelles is essential for plant survival under various environmental conditions. Plant organelles, with various functions,migrate along actin filaments and contact other types of organelles, ...The dynamic behavior of organelles is essential for plant survival under various environmental conditions. Plant organelles, with various functions,migrate along actin filaments and contact other types of organelles, leading to physical interactions at a specific site called the membrane contact site. Recent studies have revealed the importance of physical interactions in maintaining efficient metabolite flow between organelles.In this review, we first summarize peroxisome function under different environmental conditions and growth stages to understand organelle interactions. We then discuss current knowledge regarding the interactions between peroxisome and other organelles, i.e., the oil bodies, chloroplast, and mitochondria from the perspective of metabolic and physiological regulation, with reference to various organelle interactions and techniques for estimating organelle interactions occurring in plant cells.展开更多
The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens,such as the mechanism of bacterial infection,antibiotic mode of action,and bacterial antimicrobial resi...The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens,such as the mechanism of bacterial infection,antibiotic mode of action,and bacterial antimicrobial resistance.Most of these processes can be better investigated by timely tracking of fluorophore-derived antibiotics in living cells.In this paper,we will review the recent development of fluorescent antibiotics featuring the conjugation with various fluorophores,and focus on their applications in fluorescent imaging and real-time detection for various physiological processes of bacteria in vivo.展开更多
In plant cells, the Golgi apparatus consists of numerous stacks that, in turn, are composed of several flattened cisternae with a clear cis-to-trans polarity. During normal functioning within living cells, this unusua...In plant cells, the Golgi apparatus consists of numerous stacks that, in turn, are composed of several flattened cisternae with a clear cis-to-trans polarity. During normal functioning within living cells, this unusual organelle displays a wide range of dynamic behaviors such as whole stack motility, constant membrane flux through the cisternae, and Golgi enzyme recycling through the ER. In order to further investigate various aspects of Golgi stack dynamics and integrity, we co-expressed pairs of established Golgi markers in tobacco BY-2 cells to distinguish sub-compartments of the Golgi during monensin treatments, movement, and brefeldin A (BFA)-induced disassembly. A combination of cis and trans markers revealed that Golgi stacks remain intact as they move through the cytoplasm. The Golgi stack orientation during these movements showed a slight preference for the cis side moving ahead, but trans cisternae were also found at the leading edge. During BFA treatments, the different sub-compartments of about half of the observed stacks fused with the ER sequentially; however, no consistent order could be detected. In contrast, the ionophore monensin resulted in swelling of trans cisternae while medial and particularly cis cisternae were mostly unaffected. Our results thus demonstrate a re- markable equivalence of the different cisternae with respect to movement and BFA-induced fusion with the ER. In addi- tion, we propose that a combination of dual-label fluorescence microscopy and drug treatments can provide a simple alternative approach to the determination of protein localization to specific Golgi sub-compartments.展开更多
Integrin molecules are transmembraneαβheterodimers involved in cell adhesion,trafficking,and signaling.Upon activation,integrins undergo dynamic conformational changes that regulate their affinity to ligands.The phy...Integrin molecules are transmembraneαβheterodimers involved in cell adhesion,trafficking,and signaling.Upon activation,integrins undergo dynamic conformational changes that regulate their affinity to ligands.The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews,but the fluorescence imaging techniques-which are powerful tools for biological studies-have not.Here we review the fluorescence labeling methods,imaging techniques,as well as Förster resonance energy transfer assays used to study integrin expression,localization,activation,and functions.展开更多
Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achi...Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achieve rapid,optically sectioned,SR observation with hundreds to thousands of time points.However,real-time observation is still out of reach for most SIM setups as conventional algorithms for image reconstruction involve a heavy computing burden.To address this limitation,an accelerated reconstruction algorithm was developed by implementing a simplified workflow for SR-SIM,termed joint space and frequency reconstruction.This algorithm results in an 80-fold improvement in reconstruction speed relative to the widely used Wiener-SIM.Critically,the increased processing speed does not come at the expense of spatial resolution or sectioning capability,as demonstrated by live imaging of microtubule dynamics and mitochondrial tubulation.展开更多
Construction of multifunctional/multimodality nanoparticles for cancer diagnosis and therapy has become an attractive area of investigation. In this report, we designed a multimodality nanoprobe for cell labeling, and...Construction of multifunctional/multimodality nanoparticles for cancer diagnosis and therapy has become an attractive area of investigation. In this report, we designed a multimodality nanoprobe for cell labeling, and can be detectable by both magnetic resonance and near infrared (NIR) fluorescence imaging. Multiple hydrophobic superparamagnetic iron oxide (SPIO) nanocrystals are self-assembled into nanocomposites in water phase with the help of partially alkylated hyperbranched polycation, polyethylenimine (PEI), which already conjugated with the indocyanine dye Cy5.5 and can be used for cell imaging under NIR fluorescence imaging. The amphiphilic PEI/SPIO nanocomposites have a strong T 2 relaxivity. The iron uptake process in MCF-7/Adr displays a time dependent behavior. Confocal laser scanning microscopy reveals that the nanoprobes are internalized into the cytoplasm of MCF-7/Adr after 24 h labeling. Both MR and NIR fluorescence imaging showed strong image contrast against unlabeled cells. Under a clinical MRI scanner, labeled cells in gelatin phantom present much darker images than controlled ones. The T2 relaxation rate of the labeled cells is 98.2 s 1 , significantly higher than that of the control ones of 2.3 s 1 . This study provides an important alternative to label MCF-7/Adr at optimized low dosages with high efficiency, and may be useful to label other biologically important cells and track their behaviors in vivo.展开更多
Making peptide bonds is tightly controlled by genetic code and machinery which includes cofactors,ATP,and RNAs.In this regard,the stand-alone and genetic-code-independent peptide ligases constitute a new family of ren...Making peptide bonds is tightly controlled by genetic code and machinery which includes cofactors,ATP,and RNAs.In this regard,the stand-alone and genetic-code-independent peptide ligases constitute a new family of renegade peptide-bond makers.A prime example is butelase-1,an Asn/Asp(Asx)-specific ligase that structurally belongs to the asparaginyl endopeptidase family.Butelase-1 specifically recognizes a C-terminal Asx-containing tripeptide motif,Asn/Asp-Xaa-Yaa(Xaa and Yaa are any amino acids),to form a site-specific Asn-Xaa peptide bond either intramolecularly as cyclic proteins or intermolecularly as modified proteins.Our work in the past five years has validated that butelase-1 is a potent and versatile ligase.Here we review the advances in ligases,with a focus on butelase-1,and their applications in engineering bioactive peptides and precision protein modifications,antibody-drug conjugates,and live-cell labeling.展开更多
To the Editor:The current coronavirus disease-19(COVID-19)pandemic spurs the development of antiviral drugs for SARS-CoV-2,as the number of patients with viral infections continues to rise globally in the context of w...To the Editor:The current coronavirus disease-19(COVID-19)pandemic spurs the development of antiviral drugs for SARS-CoV-2,as the number of patients with viral infections continues to rise globally in the context of widespread vaccination.Targeting the interaction between the receptor binding domain(RBD)of SARS-CoV-2 spike protein and the host cell ACE2 is a promising therapeutic strategy to effectively inhibit viral entry.展开更多
The autonomous Mutator(Mu)transposon in maize(Zea mays L.)lines 115F,330I,and 715D were crossed with inbred lines B73,Mo17,97108,and H9-21,M1were self-pollinated to establish the Mu insertion-mutagenized M2seeds pool ...The autonomous Mutator(Mu)transposon in maize(Zea mays L.)lines 115F,330I,and 715D were crossed with inbred lines B73,Mo17,97108,and H9-21,M1were self-pollinated to establish the Mu insertion-mutagenized M2seeds pool and The M2plants encompassed a large amount of biological variation relevant to improving agronomy traits by observed in the field.Next we statistically analyzed these candidate mutants.Under drought stress,we screened seedlings at 3-leaf stage by using the infrared thermography,and successfully got 108 droughtinsensitive and 121 drought-sensitive candidate mutants from more than 38,000 lines,which temperature were significant different with others.These candidate mutants were primarily analyzed by infrared thermography,chlorophyll fluorescence,leaf water losing,photosynthetic characteristics,content of soluble sugars,soluble protein,and proline assay.The selected mutants were cloned by MuTAIL–PCR methods.Here we provide the better genetic materials for research on maize breeding for drought tolerance.展开更多
Herein we presented a general strategy for in situ assembly of intramolecular charge-transfer(ICT)-based light-up fluorophores via bioorthogonal Suzuki-Miyaura cross-coupling reaction.By introducing iodo group at the ...Herein we presented a general strategy for in situ assembly of intramolecular charge-transfer(ICT)-based light-up fluorophores via bioorthogonal Suzuki-Miyaura cross-coupling reaction.By introducing iodo group at the appropriate position,five fluorophores with different scaffolds including naphthalimide,coumarin,naphthalene sulfonate,nitrobenzoxadiazole,and acetonaphthone,were designed as bioorthogonal multicolor fluorogenic probes,which could produce significant fluorescence enhancement and high fluorescence quantum yield after Suzuki-Miyaura reaction with aryl boronic acid or boronate.Manipulating the substituents andπscaffold in the fluorophores allows fine-tuning of their photophysical properties.With this strategy,we succeeded in peptide conjugation,no-wash fluorogenic protein labeling,and mitochondria-selective bioorthogonal imaging in live cells.展开更多
The biogenesis of autophagosomes provides the basis for macroautophagy to capture and degrade intracellular cargoes.Binding of the autophagy-related protein ATG8/LC3 to autophagic membranes is essential to autophagoso...The biogenesis of autophagosomes provides the basis for macroautophagy to capture and degrade intracellular cargoes.Binding of the autophagy-related protein ATG8/LC3 to autophagic membranes is essential to autophagosome formation,which involves the specific and dynamic processing of ATG8/LC3 by cysteine protease ATG4.However,to date,the mechanism whereby ATG4 is recruited to the membranes,the interaction of ATG4 and ATG8/LC3 on the membranes,and its role in the growth of phagophore are not completely understood.Here,we used fluorescence recovery after photobleaching to monitor the turnover of GFP-tagged ATG4B and LC3B in living animal cells.The data show that ATG4B localizes to early autophagic membranes in an LC3B-dependent manner.During autophagy,ATG4B and LC3B undergo rapid cytosol/isolation membrane exchange but not at the cytosol/completed autophagosome.In addition,ATG4B activity controls the efficiency of autophagosome formation by impacting the membrane binding/dissociation of LC3B.These data suggest that ATG4 and LC3 play interdependent roles in the formation of autophagosomes.展开更多
Aim:To develop new therapies for prostate cancer,disease heterogeneity must be addressed.This includes patient variation,multi-focal disease,cellular heterogeneity,genomic changes and epigenetic modification.This requ...Aim:To develop new therapies for prostate cancer,disease heterogeneity must be addressed.This includes patient variation,multi-focal disease,cellular heterogeneity,genomic changes and epigenetic modification.This requires more representative models to be used in more innovative ways.Methods:This study used a panel of cell lines and primary prostate epithelial cell cultures derived from patient tissue.Several assays were used;alamar blue,colony forming assays,γH2AX and Ki67 immunofluorescence and comet assays.Ptychographic quantitative phase imaging(QPI),a label-free imaging technique,combined with Cell Analysis Toolbox software,was implemented to carry out real-time analysis of cells and to retrieve morphological,kinetic and population data.Results:A combination of radiation and Vorinostat may be more effective than radiation alone.Primary prostate cancer stem-like cells are more resistant to etoposide than more differentiated cells.Analysis of QPI images showed that cell lines and primary cells differ in their size,motility and proliferation rate.A QPI signature was developed in order to identify two subpopulations of cells within a heterogeneous primary culture.Conclusion:Use of primary prostate epithelial cultures allows assessment of therapies whilst taking into account cellular heterogeneity.Analysis of rare cell populations and embracing novel techniques may ultimately lead to identifying and overcoming treatment resistance.展开更多
In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive...In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive factor in biological research and also in all drug development steps,medicinal or preventive therapies.Experimental cell analysis is hard,expensive,and time-consuming.To overcome these difficulties,in recent years,several computational object tracking methods,software system and packages have been developed in cell sciences that bring together different disciplines and branches of technologies.Object tracking is the process of locating and monitoring specific object and its behavior in sequential images.In this paper,a comprehensive review on object tracking stages and computational methods that are utilized in terms of cell tracking has been organized.Besides,the available software packages and toolkits,challenges,and their solution in time lapse microscopy images in this scope were reviewed.The aim of describing computational cell tracking methods and tools is that biologist and cell scientists might take advantage of these computational techniques to find another method to gain complementary information for their question of interest.展开更多
基金supported by NIH-NEI grants to DRH(R01-EY018417,R01-EY024519)the Center for Zebrafish Research,University of Notre Dame,USA
文摘Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integrate and/or respond to sensory cues. In contrast, zebrafish(Danio rerio) possess an endogenous capacity to regenerate lost neurons. Here, we will focus on the processes that lead to neuronal regeneration in the zebrafish retina. Dying retinal neurons release a damage signal, tumor necrosis factor α, which induces the resident radial glia, the Müller glia, to reprogram and re-enter the cell cycle. The Müller glia divide asymmetrically to produce a Müller glia that exits the cell cycle and a neuronal progenitor cell. The arising neuronal progenitor cells undergo several rounds of cell divisions before they migrate to the site of damage to differentiate into the neuronal cell types that were lost. Molecular and immunohistochemical studies have predominantly provided insight into the mechanisms that regulate retinal regeneration. However, many processes during retinal regeneration are dynamic and require live-cell imaging to fully discern the underlying mechanisms. Recently, a multiphoton imaging approach of adult zebrafish retinal cultures was developed. We will discuss the use of live-cell imaging, the currently available tools and those that need to be developed to advance our knowledge on major open questions in the field of retinal regeneration.
基金supported in part by grants from NIH HL098472, CA139272, NS063405NSF CBET0846429,CMMI0800870the Wallace H Coulter Foundation,and the Beckman Laser Institute Inc
文摘Cells in the body are exposed to physiological and pathophysiological stimuli that encompass both chemical and mechanical factors,which coordinately modulate cellular functions. Compared to the large amount of information on cellular re-
基金Lin He and Siyi Qiu received support from the National Natural Science Foundation of China(Grant No.91851210).
文摘To determine the effects of microwave radiation at the molecular level as well as on the germination,growth and morphology of dry spores at the single-cell level.Dry Bacillus aryabhattai MCCC 1K02966 spores were microwave-treated at different powers and characterized using single-cell optical technology.As determined by laser tweezers Raman spectroscopy,the Ca^(2+)-dipicolinic acid content increased and nucleic acid denaturation occurred in response to microwave treatment.Livecell microscopy revealed that the germination and growth rates decreased as the microwave power increased.With respect to morphology,atomic force microscopy(AFM)demonstrated that spores became wrinkled and rough after microwave treatment.Furthermore,spores became smaller as the microwave power increased.Microwave treatment can damage DNA,and high-power microwaves can inhibit the germination of spores and reduce spore volumes.These results provide a new perspective on the responses of living single cells to microwave radiation and demonstrate the application of various new techniques for analyses of microorganisms at the single-cell level.
基金supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT, KAKENHI Grant-in-Aid for Scientific Research on Innovative Areas to M.N.[No.22120007])a fund to M.N. from Wyeth Foundation
文摘The dynamic behavior of organelles is essential for plant survival under various environmental conditions. Plant organelles, with various functions,migrate along actin filaments and contact other types of organelles, leading to physical interactions at a specific site called the membrane contact site. Recent studies have revealed the importance of physical interactions in maintaining efficient metabolite flow between organelles.In this review, we first summarize peroxisome function under different environmental conditions and growth stages to understand organelle interactions. We then discuss current knowledge regarding the interactions between peroxisome and other organelles, i.e., the oil bodies, chloroplast, and mitochondria from the perspective of metabolic and physiological regulation, with reference to various organelle interactions and techniques for estimating organelle interactions occurring in plant cells.
基金We are grateful for the financial support from the National Natural Science Foundation of China(21878286,21908216,21576043)Dalian Institute of Chemical Physics(DICPI201938,DICP I202006).
文摘The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens,such as the mechanism of bacterial infection,antibiotic mode of action,and bacterial antimicrobial resistance.Most of these processes can be better investigated by timely tracking of fluorophore-derived antibiotics in living cells.In this paper,we will review the recent development of fluorescent antibiotics featuring the conjugation with various fluorophores,and focus on their applications in fluorescent imaging and real-time detection for various physiological processes of bacteria in vivo.
文摘In plant cells, the Golgi apparatus consists of numerous stacks that, in turn, are composed of several flattened cisternae with a clear cis-to-trans polarity. During normal functioning within living cells, this unusual organelle displays a wide range of dynamic behaviors such as whole stack motility, constant membrane flux through the cisternae, and Golgi enzyme recycling through the ER. In order to further investigate various aspects of Golgi stack dynamics and integrity, we co-expressed pairs of established Golgi markers in tobacco BY-2 cells to distinguish sub-compartments of the Golgi during monensin treatments, movement, and brefeldin A (BFA)-induced disassembly. A combination of cis and trans markers revealed that Golgi stacks remain intact as they move through the cytoplasm. The Golgi stack orientation during these movements showed a slight preference for the cis side moving ahead, but trans cisternae were also found at the leading edge. During BFA treatments, the different sub-compartments of about half of the observed stacks fused with the ER sequentially; however, no consistent order could be detected. In contrast, the ionophore monensin resulted in swelling of trans cisternae while medial and particularly cis cisternae were mostly unaffected. Our results thus demonstrate a re- markable equivalence of the different cisternae with respect to movement and BFA-induced fusion with the ER. In addi- tion, we propose that a combination of dual-label fluorescence microscopy and drug treatments can provide a simple alternative approach to the determination of protein localization to specific Golgi sub-compartments.
基金This work was supported by funding from the National Institutes of Health,USA(NIH,R01HL145454)a startup fund from UConn Health.
文摘Integrin molecules are transmembraneαβheterodimers involved in cell adhesion,trafficking,and signaling.Upon activation,integrins undergo dynamic conformational changes that regulate their affinity to ligands.The physiological functions and activation mechanisms of integrins have been heavily discussed in previous studies and reviews,but the fluorescence imaging techniques-which are powerful tools for biological studies-have not.Here we review the fluorescence labeling methods,imaging techniques,as well as Förster resonance energy transfer assays used to study integrin expression,localization,activation,and functions.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 62005208, 62135003, and 61905189)Innovation Capability Support Program of Shaanxi (No. 2021TD-57)+1 种基金China Postdoctoral Science Foundation (Nos. 2020M673365 and 2019M663656)National Institutes of Health Grant GM100156 to PRB
文摘Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achieve rapid,optically sectioned,SR observation with hundreds to thousands of time points.However,real-time observation is still out of reach for most SIM setups as conventional algorithms for image reconstruction involve a heavy computing burden.To address this limitation,an accelerated reconstruction algorithm was developed by implementing a simplified workflow for SR-SIM,termed joint space and frequency reconstruction.This algorithm results in an 80-fold improvement in reconstruction speed relative to the widely used Wiener-SIM.Critically,the increased processing speed does not come at the expense of spatial resolution or sectioning capability,as demonstrated by live imaging of microtubule dynamics and mitochondrial tubulation.
基金supported by the Program for New Century Excellent Talents in University (NCET-06-0781)the Distinguished Young Scholars Project of Sichuan Province (06ZQ026-007)+1 种基金the Doctoral Fund of Ministry of Education of China (20090181110068)the National Natural Science Foundation of China (20974065, 51173117 and 50830107)
文摘Construction of multifunctional/multimodality nanoparticles for cancer diagnosis and therapy has become an attractive area of investigation. In this report, we designed a multimodality nanoprobe for cell labeling, and can be detectable by both magnetic resonance and near infrared (NIR) fluorescence imaging. Multiple hydrophobic superparamagnetic iron oxide (SPIO) nanocrystals are self-assembled into nanocomposites in water phase with the help of partially alkylated hyperbranched polycation, polyethylenimine (PEI), which already conjugated with the indocyanine dye Cy5.5 and can be used for cell imaging under NIR fluorescence imaging. The amphiphilic PEI/SPIO nanocomposites have a strong T 2 relaxivity. The iron uptake process in MCF-7/Adr displays a time dependent behavior. Confocal laser scanning microscopy reveals that the nanoprobes are internalized into the cytoplasm of MCF-7/Adr after 24 h labeling. Both MR and NIR fluorescence imaging showed strong image contrast against unlabeled cells. Under a clinical MRI scanner, labeled cells in gelatin phantom present much darker images than controlled ones. The T2 relaxation rate of the labeled cells is 98.2 s 1 , significantly higher than that of the control ones of 2.3 s 1 . This study provides an important alternative to label MCF-7/Adr at optimized low dosages with high efficiency, and may be useful to label other biologically important cells and track their behaviors in vivo.
基金supported by Academic Research Grant Tier 3(MOE2016-T3-1-003)from the Singapore Ministry of Education.
文摘Making peptide bonds is tightly controlled by genetic code and machinery which includes cofactors,ATP,and RNAs.In this regard,the stand-alone and genetic-code-independent peptide ligases constitute a new family of renegade peptide-bond makers.A prime example is butelase-1,an Asn/Asp(Asx)-specific ligase that structurally belongs to the asparaginyl endopeptidase family.Butelase-1 specifically recognizes a C-terminal Asx-containing tripeptide motif,Asn/Asp-Xaa-Yaa(Xaa and Yaa are any amino acids),to form a site-specific Asn-Xaa peptide bond either intramolecularly as cyclic proteins or intermolecularly as modified proteins.Our work in the past five years has validated that butelase-1 is a potent and versatile ligase.Here we review the advances in ligases,with a focus on butelase-1,and their applications in engineering bioactive peptides and precision protein modifications,antibody-drug conjugates,and live-cell labeling.
基金supported by the National Natural Science Foundation of China (22078314, 21878286, 21908216)Dalian Institute of Chemical Physics (DICPI202142, DICPI202006, DICPI201938, DICPZZBS201805, China)
文摘To the Editor:The current coronavirus disease-19(COVID-19)pandemic spurs the development of antiviral drugs for SARS-CoV-2,as the number of patients with viral infections continues to rise globally in the context of widespread vaccination.Targeting the interaction between the receptor binding domain(RBD)of SARS-CoV-2 spike protein and the host cell ACE2 is a promising therapeutic strategy to effectively inhibit viral entry.
基金supported by the National Key Basic Research and Development Program of China(2012CB 114301)
文摘The autonomous Mutator(Mu)transposon in maize(Zea mays L.)lines 115F,330I,and 715D were crossed with inbred lines B73,Mo17,97108,and H9-21,M1were self-pollinated to establish the Mu insertion-mutagenized M2seeds pool and The M2plants encompassed a large amount of biological variation relevant to improving agronomy traits by observed in the field.Next we statistically analyzed these candidate mutants.Under drought stress,we screened seedlings at 3-leaf stage by using the infrared thermography,and successfully got 108 droughtinsensitive and 121 drought-sensitive candidate mutants from more than 38,000 lines,which temperature were significant different with others.These candidate mutants were primarily analyzed by infrared thermography,chlorophyll fluorescence,leaf water losing,photosynthetic characteristics,content of soluble sugars,soluble protein,and proline assay.The selected mutants were cloned by MuTAIL–PCR methods.Here we provide the better genetic materials for research on maize breeding for drought tolerance.
基金supported by the Beijing Nova Program(No.Z201100006820049)the National Natural Science Foundation of China(No.21907109)the CAMS Innovation Fund for Graduate Students(No.2019–1007–03)
文摘Herein we presented a general strategy for in situ assembly of intramolecular charge-transfer(ICT)-based light-up fluorophores via bioorthogonal Suzuki-Miyaura cross-coupling reaction.By introducing iodo group at the appropriate position,five fluorophores with different scaffolds including naphthalimide,coumarin,naphthalene sulfonate,nitrobenzoxadiazole,and acetonaphthone,were designed as bioorthogonal multicolor fluorogenic probes,which could produce significant fluorescence enhancement and high fluorescence quantum yield after Suzuki-Miyaura reaction with aryl boronic acid or boronate.Manipulating the substituents andπscaffold in the fluorophores allows fine-tuning of their photophysical properties.With this strategy,we succeeded in peptide conjugation,no-wash fluorogenic protein labeling,and mitochondria-selective bioorthogonal imaging in live cells.
基金the National Natural Science Foundation of China(31671434,31701203,81420108017,81525010,and 91749203)the National Key Research and Development Program of China(2016YFA0100602,2017YFA0103302,2020YFA0112404,and 2018YFC2000705)+1 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2017ZT07S347)the Fundamental Research Funds for the Central Universities(21617336).
文摘The biogenesis of autophagosomes provides the basis for macroautophagy to capture and degrade intracellular cargoes.Binding of the autophagy-related protein ATG8/LC3 to autophagic membranes is essential to autophagosome formation,which involves the specific and dynamic processing of ATG8/LC3 by cysteine protease ATG4.However,to date,the mechanism whereby ATG4 is recruited to the membranes,the interaction of ATG4 and ATG8/LC3 on the membranes,and its role in the growth of phagophore are not completely understood.Here,we used fluorescence recovery after photobleaching to monitor the turnover of GFP-tagged ATG4B and LC3B in living animal cells.The data show that ATG4B localizes to early autophagic membranes in an LC3B-dependent manner.During autophagy,ATG4B and LC3B undergo rapid cytosol/isolation membrane exchange but not at the cytosol/completed autophagosome.In addition,ATG4B activity controls the efficiency of autophagosome formation by impacting the membrane binding/dissociation of LC3B.These data suggest that ATG4 and LC3 play interdependent roles in the formation of autophagosomes.
基金funded by a PCUK Innovation Award-RIA15-ST2-022.SK was supported by a White Rose Fund studentship.
文摘Aim:To develop new therapies for prostate cancer,disease heterogeneity must be addressed.This includes patient variation,multi-focal disease,cellular heterogeneity,genomic changes and epigenetic modification.This requires more representative models to be used in more innovative ways.Methods:This study used a panel of cell lines and primary prostate epithelial cell cultures derived from patient tissue.Several assays were used;alamar blue,colony forming assays,γH2AX and Ki67 immunofluorescence and comet assays.Ptychographic quantitative phase imaging(QPI),a label-free imaging technique,combined with Cell Analysis Toolbox software,was implemented to carry out real-time analysis of cells and to retrieve morphological,kinetic and population data.Results:A combination of radiation and Vorinostat may be more effective than radiation alone.Primary prostate cancer stem-like cells are more resistant to etoposide than more differentiated cells.Analysis of QPI images showed that cell lines and primary cells differ in their size,motility and proliferation rate.A QPI signature was developed in order to identify two subpopulations of cells within a heterogeneous primary culture.Conclusion:Use of primary prostate epithelial cultures allows assessment of therapies whilst taking into account cellular heterogeneity.Analysis of rare cell populations and embracing novel techniques may ultimately lead to identifying and overcoming treatment resistance.
文摘In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive factor in biological research and also in all drug development steps,medicinal or preventive therapies.Experimental cell analysis is hard,expensive,and time-consuming.To overcome these difficulties,in recent years,several computational object tracking methods,software system and packages have been developed in cell sciences that bring together different disciplines and branches of technologies.Object tracking is the process of locating and monitoring specific object and its behavior in sequential images.In this paper,a comprehensive review on object tracking stages and computational methods that are utilized in terms of cell tracking has been organized.Besides,the available software packages and toolkits,challenges,and their solution in time lapse microscopy images in this scope were reviewed.The aim of describing computational cell tracking methods and tools is that biologist and cell scientists might take advantage of these computational techniques to find another method to gain complementary information for their question of interest.