An actin gene (CfACT1) was cloned by using RT-PCR, 3’and 5’RACE from hemocytes of the sea scallop Chlamys farreri. The full length of the transcript is 1 535 bp, which contains a long 3’ un-translated region of 436...An actin gene (CfACT1) was cloned by using RT-PCR, 3’and 5’RACE from hemocytes of the sea scallop Chlamys farreri. The full length of the transcript is 1 535 bp, which contains a long 3’ un-translated region of 436bp and 59bp of a 5’ un-translated sequence. The open reading frame encodes a polypeptide of 376 amino acids. Sequence comparisons indicated that CfACT1 is more closely related to vertebrate cytoplasmic actins than muscle types. Phylogenetic analysis showed that molluscan actins could be generally divided into two categories: muscle and cytoplasmic, although both are similar to vertebrate cytoplasmic actins. It was also inferred that different isotypes existed in muscle or cytoplasma in mollusks. The genomic sequence of CfACT1 was cloned and sequenced. Only one intron was detected: it was located between codons 42 and 43 and different from vertebrate actin genes.展开更多
Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at th...Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.展开更多
BACKGROUND:The present study aims to investigate whether mannitol facilitates central nervous system(CNS) entry of vancomycin and alleviates methicillin-resistant Staphylococcus aureus(MRSA)intracranial infection.METH...BACKGROUND:The present study aims to investigate whether mannitol facilitates central nervous system(CNS) entry of vancomycin and alleviates methicillin-resistant Staphylococcus aureus(MRSA)intracranial infection.METHODS:Blood-brain barrier(BBB) permeability was assessed by measuring the concentration of sodium fl uorescein(NaF) in the brain tissues of rats and fl uorescein isothiocyanate-dextran(FITC-dextran)in a single-cell layer model.Neutrophil infiltration in the brain tissue,inflammatory cytokine levels in the serum,neurological function,and 7-day survival rates were used to evaluate therapeutic eff ects of mannitol and vancomycin in MRSA-infected rats.Syndecan-1 and fi lamentous actin(F-actin) levels were measured,and the relationship between F-actin and the endothelial glycocalyx layer(EGL) was explored via the depolymerization agent cytochalasin D and the polymerization agent jasplakinolide.RESULTS:Following mannitol administration,the NaF and vancomycin concentrations in the brain tissue increased rapidly within 5 min and remained stable for 30 min,indicating that mannitol increased BBB permeability for 30 min.In vitro,mannitol treatment led to significantly greater FITC-dextran permeation through a single-cell layer compared to controls.In the MRSA intracranial infection model,rats treated with mannitol and vancomycin simultaneously presented less infl ammation,improved neurological function,and increased 7-day survival rate compared to rats treated with vancomycin and mannitol at 10-hour intervals.Further experiments revealed that mannitol decreased the expression of syndecan-1 in brain tissues,which was confi rmed by in vitro experiments showing that mannitol signifi cantly decreased syndecan-1 via F-actin depolymerization.CONCLUSION:Mannitol may enhance the therapeutic effi cacy of vancomycin against intracranial MRSA infection by decreasing the endothelial glycocalyx of the BBB via F-actin depolymerization.展开更多
Cell division is a fundamental biological process in which a parent cell divides into two daughter cells.The cell cortex,a thin layer primarily composed of actin filaments and myosin motors beneath the plasma membrane...Cell division is a fundamental biological process in which a parent cell divides into two daughter cells.The cell cortex,a thin layer primarily composed of actin filaments and myosin motors beneath the plasma membrane,plays a critical role in ensuring proper cell division.In this study,we apply a hydrodynamic model to describe the actin cortex as an active nematic surface,incorporating orientational order arising from actin filament alignment and anisotropic active stress produced by myosin motors.By analyzing the linearized dynamics,we investigate how shape,flow,and stress regulators evolve over time when the surface deviates slightly from a sphere.Our findings reveal that the active alignment of actin filaments,often overlooked in previous studies,is crucial for successful division.Furthermore,we demonstrate that a cortical chiral flow naturally emerges as a consequence of this active alignment.Overall,our results provide a mechanistic explanation for key phenomena observed during cell division,offering new insights into the role of active stress and filament alignment in cortical dynamics.展开更多
利用SMART(switching mechanismat5’end of RNA transcript)技术,提取果实少量总RNA,经15-25轮LD-PCR扩增获得全长ds-cDNA,构建了海南主栽的食用香蕉巴西蕉(Musa AAA Group Cavendish)果实的cDNA文库。所构建的文库容量为5×106Pfu...利用SMART(switching mechanismat5’end of RNA transcript)技术,提取果实少量总RNA,经15-25轮LD-PCR扩增获得全长ds-cDNA,构建了海南主栽的食用香蕉巴西蕉(Musa AAA Group Cavendish)果实的cDNA文库。所构建的文库容量为5×106Pfuml-1,重组率93%。利用此cDNA文库,采用96孔板PCR法筛选香蕉Actin2基因,测序结果显示,序列全长1723bp,编码区长1134bp,编码378个氨基酸,与蝴蝶兰Actin2基因序列同源率达83%,已递交GenBank,接受号692696。展开更多
基金Supported by the National Basic Research Program of China (973 Program, No. G1999012012)the Key Laboratory of Mariculture, Ministry of Education (No. 2004024)
文摘An actin gene (CfACT1) was cloned by using RT-PCR, 3’and 5’RACE from hemocytes of the sea scallop Chlamys farreri. The full length of the transcript is 1 535 bp, which contains a long 3’ un-translated region of 436bp and 59bp of a 5’ un-translated sequence. The open reading frame encodes a polypeptide of 376 amino acids. Sequence comparisons indicated that CfACT1 is more closely related to vertebrate cytoplasmic actins than muscle types. Phylogenetic analysis showed that molluscan actins could be generally divided into two categories: muscle and cytoplasmic, although both are similar to vertebrate cytoplasmic actins. It was also inferred that different isotypes existed in muscle or cytoplasma in mollusks. The genomic sequence of CfACT1 was cloned and sequenced. Only one intron was detected: it was located between codons 42 and 43 and different from vertebrate actin genes.
基金supported by the National Key Research and Development Program of China,No.2021ZD0202503(to AHT)the National Natural Science Foundation of China,Nos.31872759(to AHT)and 32070707(to CF)+1 种基金Shenzhen Science and Technology Program,No.RCJC20210609104333007(to ZW)Shenzhen-Hong Kong Institute of Brain Science,Shenzhen Fundamental Research Institutions,No.2021SHIBS0002(to ZW).
文摘Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.
基金supported by the National Natural Science Foundation for Young Scientists of China (grant no.2002074)the Natural Science Foundation of Guangdong Province(2023A1515010267, 2023A1515012665, 2024A1515010073)+1 种基金the China International Medical Foundation Cerebrovascular Disease Youth Innovation Fund (Z-2016-20-2201)the Medical Leading Talents Fund of Guangdong Province (KJ012019430)。
文摘BACKGROUND:The present study aims to investigate whether mannitol facilitates central nervous system(CNS) entry of vancomycin and alleviates methicillin-resistant Staphylococcus aureus(MRSA)intracranial infection.METHODS:Blood-brain barrier(BBB) permeability was assessed by measuring the concentration of sodium fl uorescein(NaF) in the brain tissues of rats and fl uorescein isothiocyanate-dextran(FITC-dextran)in a single-cell layer model.Neutrophil infiltration in the brain tissue,inflammatory cytokine levels in the serum,neurological function,and 7-day survival rates were used to evaluate therapeutic eff ects of mannitol and vancomycin in MRSA-infected rats.Syndecan-1 and fi lamentous actin(F-actin) levels were measured,and the relationship between F-actin and the endothelial glycocalyx layer(EGL) was explored via the depolymerization agent cytochalasin D and the polymerization agent jasplakinolide.RESULTS:Following mannitol administration,the NaF and vancomycin concentrations in the brain tissue increased rapidly within 5 min and remained stable for 30 min,indicating that mannitol increased BBB permeability for 30 min.In vitro,mannitol treatment led to significantly greater FITC-dextran permeation through a single-cell layer compared to controls.In the MRSA intracranial infection model,rats treated with mannitol and vancomycin simultaneously presented less infl ammation,improved neurological function,and increased 7-day survival rate compared to rats treated with vancomycin and mannitol at 10-hour intervals.Further experiments revealed that mannitol decreased the expression of syndecan-1 in brain tissues,which was confi rmed by in vitro experiments showing that mannitol signifi cantly decreased syndecan-1 via F-actin depolymerization.CONCLUSION:Mannitol may enhance the therapeutic effi cacy of vancomycin against intracranial MRSA infection by decreasing the endothelial glycocalyx of the BBB via F-actin depolymerization.
基金support from the National Nat-ural Science Foundation of China(Grant No.12474199)the Fundamental Research Funds for Central Universities of China(Grant No.20720240144),and 111 Project(B16029).
文摘Cell division is a fundamental biological process in which a parent cell divides into two daughter cells.The cell cortex,a thin layer primarily composed of actin filaments and myosin motors beneath the plasma membrane,plays a critical role in ensuring proper cell division.In this study,we apply a hydrodynamic model to describe the actin cortex as an active nematic surface,incorporating orientational order arising from actin filament alignment and anisotropic active stress produced by myosin motors.By analyzing the linearized dynamics,we investigate how shape,flow,and stress regulators evolve over time when the surface deviates slightly from a sphere.Our findings reveal that the active alignment of actin filaments,often overlooked in previous studies,is crucial for successful division.Furthermore,we demonstrate that a cortical chiral flow naturally emerges as a consequence of this active alignment.Overall,our results provide a mechanistic explanation for key phenomena observed during cell division,offering new insights into the role of active stress and filament alignment in cortical dynamics.
文摘利用SMART(switching mechanismat5’end of RNA transcript)技术,提取果实少量总RNA,经15-25轮LD-PCR扩增获得全长ds-cDNA,构建了海南主栽的食用香蕉巴西蕉(Musa AAA Group Cavendish)果实的cDNA文库。所构建的文库容量为5×106Pfuml-1,重组率93%。利用此cDNA文库,采用96孔板PCR法筛选香蕉Actin2基因,测序结果显示,序列全长1723bp,编码区长1134bp,编码378个氨基酸,与蝴蝶兰Actin2基因序列同源率达83%,已递交GenBank,接受号692696。
