AIM: To investigated if paclitaxel can attenuate hepatic fi brosis in rat hepatic stellate cells (RHSCs). METHODS: RHSCs were cultured in vitro and randomly assigned to four groups: normal control group (treated only ...AIM: To investigated if paclitaxel can attenuate hepatic fi brosis in rat hepatic stellate cells (RHSCs). METHODS: RHSCs were cultured in vitro and randomly assigned to four groups: normal control group (treated only with Dulbecco's Modified Eagle's Medium), Taxol group (200 nmol/L paclitaxel was added to the cell culture), transforming growth factor (TGF)-β group (5 ng/mL recombinant human TGF-β1 was added to the cell culture), and TGF-β + Taxol group. TGF-β signaling cascade and status of various extracellular matrix proteins were evaluated by real time reverse transcriptase polymerase chain reaction and Western blotting. RESULTS: The paclitaxel treatment markedly suppressed Smad2/3 phosphorylation. This was associated with attenuated expression of collagen Ⅰ and Ⅲ and fi bronectin in RHSCs.CONCLUSION: These data indicate that 200 nmol/L paclitaxel ameliorates hepatic fi brosis via modulating TGF-β signaling, and that paclitaxel may have some therapeutic value in humans with hepatic fi brosis.展开更多
Objective： To investigate the impact of beta-elemene injection on the growth and alpha-tubule of human hepatocarcinoma HepG2 cells. Methods： Cell proliferation was assessed by MTT assay. Cell cycle distribution was ...Objective： To investigate the impact of beta-elemene injection on the growth and alpha-tubule of human hepatocarcinoma HepG2 cells. Methods： Cell proliferation was assessed by MTT assay. Cell cycle distribution was detected by flow cytometry （FCM）. The mRNA expression of alpha-tubulin was measured by RT-PCR. Western blot analysis was used to determine protein expression of alpha-tubulin and the polymerization of tubulin. Results： Beta-elemene injection inhibited HepG2 cells proliferation in a dose- and time-dependent manner; FCM analysis indicated beta-elemene injection induced cell cycle arrested at S phase. RT-PCR and western- blot analysis showed that beta-elemene injection down-regulated alpha-tublin at both mRNA and protein levels, presenting a dose-dependent manner. Moreover, beta-elemene injection reduced the polymerization of microtubules in a dose-dependent manner. Conclusions： Beta-elemene injection can inhibit the proliferation of hepatoma HepG2 cells and induce cell apoptosis, the mechanism might be partly related to the down-regulation of alpha-tubulin and inhibition of microtubular polymerization.展开更多
To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of t...To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.展开更多
Radially arranged cortical microtubules are a prominent feature of guard cells. Guard cells expressing GFP- tubulin showed consistent changes in the appearance of microtubules when stomata opened or closed. Guard cell...Radially arranged cortical microtubules are a prominent feature of guard cells. Guard cells expressing GFP- tubulin showed consistent changes in the appearance of microtubules when stomata opened or closed. Guard cells showed fewer microtubule structures as stomata closed, whether induced by transfer to darkness, ABA, hydrogen per- oxide, or sodium hydrogen carbonate. Guard cells kept in the dark （closed stomata） showed increases in microtubule struc- tures and stomatal aperture on light treatment. GFP-EB1, marking microtubule growing plus ends, showed no change in number of plus ends or velocity of assembly on stomatal closure. Since the number of growing plus ends and the rate of plus-end growth did not change when microtubule structure numbers declined, microtubule instability and/or rearrange- ment must be responsible for the apparent loss of microtubules. Guard cells with closed stomata showed more cytosolic GFP-fluorescence than those with open stomata as cortical microtubules became disassembled, although with a large net loss in total fluorescence. Microtubule-targeted drugs blocked guard-cell function in Vicia and Arabidopsis. Oryzalin dis- rupted guard-cell microtubules and prevented stomatal opening and taxol stabilized guard-cell microtubules and delayed stomatal closure. Gas exchange measurements indicated that the transgenes for fluorescent-labeled proteins did not dis- rupt normal stomatal function. These dynamic changes in guard-cell microtubules combined with our inhibitor studies provide evidence for an active role of microtubules in guard-cell function.展开更多
The distribution of F-actin and microtubules was investigated in pollen and pollen tubes of Ginkgo biloba L. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. A dense F-act...The distribution of F-actin and microtubules was investigated in pollen and pollen tubes of Ginkgo biloba L. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. A dense F-actin network was found in hydrated Ginkgo pollen. When Ginkgo pollen was germinating, F-actin mesh was found under the plasma membrane from which the pollen tube would emerge. After pollen germination, F-actin bundles were distributed axially in long pollen tubes of G. biloba. Thick F-actin bundles and network were found in the tip of the Ginkgo pollen tube, which is opposite to the results reported for the pollen tubes of some angiosperms and conifers. In addition, a few circular F-actin bundles were found in Ginkgo pollen tubes. Using immunofluorescence labeling, a dense microtubule network was found in hydrated Ginkgo pollen under confocal microscope. In the Ginkgo pollen tube, the microtubules were distributed along the longitudinal axis and extended to the tip. These results suggest that the cytoskeleton may have an essential role in the germination of Ginkgo pollen and tube growth.展开更多
Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sen...Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.展开更多
The accumulation of hyperphosphorylated tau is a common feature of several dementias. Tau is one of the brain microtubule-associated proteins. Here we discuss tau＇s functions in microtubule assembly and stabilization...The accumulation of hyperphosphorylated tau is a common feature of several dementias. Tau is one of the brain microtubule-associated proteins. Here we discuss tau＇s functions in microtubule assembly and stabilization and with regard to its interactions with other proteins. We describe and analyze important post-translational modifications： hyperphosphorylation, ubiquitination, glycation, glycosytation, nitration, polyamination, proteolysis, acetylation, and methylation. We discuss how these post-translational modifications can alter tau＇s biological function. We analyze the role of mitochondrial health in neurodegeneration. We propose that microtubules could be a therapeutic target and review different approaches. Finally, we consider whether tau accumulation or its conformational change is related to tau-induced neurodegeneration, and propose a mechanism of neurodegeneration.展开更多
人stathmin也称原癌基因蛋白18(oncogene protein 18,Op18),是一种广泛存在于细胞质的蛋白质,其相对分子质量约为19×103,可与微管蛋白结合,参与微管和纺锤体的组装;与细胞的增殖、分化、再生和运动均有关,并具有信号活性调节的功...人stathmin也称原癌基因蛋白18(oncogene protein 18,Op18),是一种广泛存在于细胞质的蛋白质,其相对分子质量约为19×103,可与微管蛋白结合,参与微管和纺锤体的组装;与细胞的增殖、分化、再生和运动均有关,并具有信号活性调节的功能。近年来有研究发现,stathmin在多种肿瘤中高表达,并可通过调节微管的解聚,促进肿瘤细胞的运动及侵袭。Stathmin翻译后修饰状态的改变,可影响与p53蛋白的相互作用,参与肿瘤的发生发展。目前单独或者联合化疗药物使用的抗stathmin效应剂已用于某些肿瘤的治疗。虽然stathmin与肿瘤病因学的内在联系尚不十分清楚,但其作为一个潜在的肿瘤标志物或药物靶点值得进一步研究探讨。展开更多
The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intr...The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intracellular transport, replication, and egress process, although many detailed mechanisms are still unclear. This article provides a brief overview of the function of the most prominent flaviviruses-induced or-hijacked cytoskeletal structures including actin, microtubules and intermediate filaments, mainly focus on infection by dengue virus, Zika virus and West Nile virus. We suggest that virus interaction with host cytoskeleton to be an interesting area of future research.展开更多
In this contribution results from different disciplines of science were compared to show their intimate interweaving with each other having in common the golden ratio <i><span style="font-family:Verdana;...In this contribution results from different disciplines of science were compared to show their intimate interweaving with each other having in common the golden ratio <i><span style="font-family:Verdana;">φ</span></i><span style="font-family:Verdana;"> respectively its fifth power </span><i><span style="font-family:Verdana;">φ</span></i><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;">. The research fields cover model calculations of statistical physics associated with phase transitions, the quantum probability of two particles, new physics of everything suggested by the information relativity theory (</span><i><span style="font-family:Verdana;">IRT</span></i><span style="font-family:Verdana;">) including explanations of cosmological relevance, the </span><i><span style="font-family:Verdana;">ε</span></i><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">infinity theory, superconductivity, and the </span><i><span style="font-family:Verdana;">Tammes</span></i><span style="font-family:Verdana;"> problem of the largest diameter of </span><i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;"> non-overlapping circles on the surface of a sphere with its connection to viral morphology and crystallography. Finally, </span><i><span style="font-family:Verdana;">Fibo</span><span style="font-family:Verdana;">nacci</span></i><span style="font-family:Verdana;"> anyons proposed for topological quantum</span><span style="font-family:Verdana;"> computation (</span><i><span style="font-family:Verdana;">TQC</span></i><span style="font-family:Verdana;">) were briefly described in comparison to the recently formulated reverse </span><i><span style="font-family:Verdana;">Fibonacci</span></i><span style="font-family:Verdana;"> approach using the </span><span style="font-family:Verdana;"><em>Jani</em></span></s展开更多
The endoplasmic reticulum forms the first compart- ment in a series of organelles which comprise the secretory pathway, it takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and...The endoplasmic reticulum forms the first compart- ment in a series of organelles which comprise the secretory pathway, it takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.展开更多
基金Supported by Grants from the Creative Research Group Fund of the National Foundation Committee of Natural Science of China, No. 30871169/C140405
文摘AIM: To investigated if paclitaxel can attenuate hepatic fi brosis in rat hepatic stellate cells (RHSCs). METHODS: RHSCs were cultured in vitro and randomly assigned to four groups: normal control group (treated only with Dulbecco's Modified Eagle's Medium), Taxol group (200 nmol/L paclitaxel was added to the cell culture), transforming growth factor (TGF)-β group (5 ng/mL recombinant human TGF-β1 was added to the cell culture), and TGF-β + Taxol group. TGF-β signaling cascade and status of various extracellular matrix proteins were evaluated by real time reverse transcriptase polymerase chain reaction and Western blotting. RESULTS: The paclitaxel treatment markedly suppressed Smad2/3 phosphorylation. This was associated with attenuated expression of collagen Ⅰ and Ⅲ and fi bronectin in RHSCs.CONCLUSION: These data indicate that 200 nmol/L paclitaxel ameliorates hepatic fi brosis via modulating TGF-β signaling, and that paclitaxel may have some therapeutic value in humans with hepatic fi brosis.
基金The General Program of National Natural Science Foundation of China:Research Fund for the mechanism of Arenobufagin space isomer inhibits lymphatic metastasis of mouse hepatocarcinomaThe Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education MinistrySpecialized Research Fund for the Doctoral Program of Higher Education(NO.20102105120002)
文摘Objective： To investigate the impact of beta-elemene injection on the growth and alpha-tubule of human hepatocarcinoma HepG2 cells. Methods： Cell proliferation was assessed by MTT assay. Cell cycle distribution was detected by flow cytometry （FCM）. The mRNA expression of alpha-tubulin was measured by RT-PCR. Western blot analysis was used to determine protein expression of alpha-tubulin and the polymerization of tubulin. Results： Beta-elemene injection inhibited HepG2 cells proliferation in a dose- and time-dependent manner; FCM analysis indicated beta-elemene injection induced cell cycle arrested at S phase. RT-PCR and western- blot analysis showed that beta-elemene injection down-regulated alpha-tublin at both mRNA and protein levels, presenting a dose-dependent manner. Moreover, beta-elemene injection reduced the polymerization of microtubules in a dose-dependent manner. Conclusions： Beta-elemene injection can inhibit the proliferation of hepatoma HepG2 cells and induce cell apoptosis, the mechanism might be partly related to the down-regulation of alpha-tubulin and inhibition of microtubular polymerization.
文摘To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.
文摘Radially arranged cortical microtubules are a prominent feature of guard cells. Guard cells expressing GFP- tubulin showed consistent changes in the appearance of microtubules when stomata opened or closed. Guard cells showed fewer microtubule structures as stomata closed, whether induced by transfer to darkness, ABA, hydrogen per- oxide, or sodium hydrogen carbonate. Guard cells kept in the dark （closed stomata） showed increases in microtubule struc- tures and stomatal aperture on light treatment. GFP-EB1, marking microtubule growing plus ends, showed no change in number of plus ends or velocity of assembly on stomatal closure. Since the number of growing plus ends and the rate of plus-end growth did not change when microtubule structure numbers declined, microtubule instability and/or rearrange- ment must be responsible for the apparent loss of microtubules. Guard cells with closed stomata showed more cytosolic GFP-fluorescence than those with open stomata as cortical microtubules became disassembled, although with a large net loss in total fluorescence. Microtubule-targeted drugs blocked guard-cell function in Vicia and Arabidopsis. Oryzalin dis- rupted guard-cell microtubules and prevented stomatal opening and taxol stabilized guard-cell microtubules and delayed stomatal closure. Gas exchange measurements indicated that the transgenes for fluorescent-labeled proteins did not dis- rupt normal stomatal function. These dynamic changes in guard-cell microtubules combined with our inhibitor studies provide evidence for an active role of microtubules in guard-cell function.
文摘The distribution of F-actin and microtubules was investigated in pollen and pollen tubes of Ginkgo biloba L. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. A dense F-actin network was found in hydrated Ginkgo pollen. When Ginkgo pollen was germinating, F-actin mesh was found under the plasma membrane from which the pollen tube would emerge. After pollen germination, F-actin bundles were distributed axially in long pollen tubes of G. biloba. Thick F-actin bundles and network were found in the tip of the Ginkgo pollen tube, which is opposite to the results reported for the pollen tubes of some angiosperms and conifers. In addition, a few circular F-actin bundles were found in Ginkgo pollen tubes. Using immunofluorescence labeling, a dense microtubule network was found in hydrated Ginkgo pollen under confocal microscope. In the Ginkgo pollen tube, the microtubules were distributed along the longitudinal axis and extended to the tip. These results suggest that the cytoskeleton may have an essential role in the germination of Ginkgo pollen and tube growth.
文摘Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.
基金supported in part by an NIH grant(R15AG034524-01)an Alzheimer’s Association(Chicago,IL)grant(IIRG-09-133206)a Brooklyn Home for the Aged Man grant for the support of developing Alzheimer research at CSI
文摘The accumulation of hyperphosphorylated tau is a common feature of several dementias. Tau is one of the brain microtubule-associated proteins. Here we discuss tau＇s functions in microtubule assembly and stabilization and with regard to its interactions with other proteins. We describe and analyze important post-translational modifications： hyperphosphorylation, ubiquitination, glycation, glycosytation, nitration, polyamination, proteolysis, acetylation, and methylation. We discuss how these post-translational modifications can alter tau＇s biological function. We analyze the role of mitochondrial health in neurodegeneration. We propose that microtubules could be a therapeutic target and review different approaches. Finally, we consider whether tau accumulation or its conformational change is related to tau-induced neurodegeneration, and propose a mechanism of neurodegeneration.
文摘人stathmin也称原癌基因蛋白18(oncogene protein 18,Op18),是一种广泛存在于细胞质的蛋白质,其相对分子质量约为19×103,可与微管蛋白结合,参与微管和纺锤体的组装;与细胞的增殖、分化、再生和运动均有关,并具有信号活性调节的功能。近年来有研究发现,stathmin在多种肿瘤中高表达,并可通过调节微管的解聚,促进肿瘤细胞的运动及侵袭。Stathmin翻译后修饰状态的改变,可影响与p53蛋白的相互作用,参与肿瘤的发生发展。目前单独或者联合化疗药物使用的抗stathmin效应剂已用于某些肿瘤的治疗。虽然stathmin与肿瘤病因学的内在联系尚不十分清楚,但其作为一个潜在的肿瘤标志物或药物靶点值得进一步研究探讨。
基金supported by Collaborative Research Grant (KLMVI-OP-201904) of CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciencesthe starting Grant of Institut Pasteur of Shanghai (1185170000), Chinese Academy of Sciences
文摘The family of flaviviruses is one of the most medically important groups of emerging arthropod-borne viruses. Host cell cytoskeletons have been reported to have close contact with flaviviruses during virus entry, intracellular transport, replication, and egress process, although many detailed mechanisms are still unclear. This article provides a brief overview of the function of the most prominent flaviviruses-induced or-hijacked cytoskeletal structures including actin, microtubules and intermediate filaments, mainly focus on infection by dengue virus, Zika virus and West Nile virus. We suggest that virus interaction with host cytoskeleton to be an interesting area of future research.
文摘In this contribution results from different disciplines of science were compared to show their intimate interweaving with each other having in common the golden ratio <i><span style="font-family:Verdana;">φ</span></i><span style="font-family:Verdana;"> respectively its fifth power </span><i><span style="font-family:Verdana;">φ</span></i><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;">. The research fields cover model calculations of statistical physics associated with phase transitions, the quantum probability of two particles, new physics of everything suggested by the information relativity theory (</span><i><span style="font-family:Verdana;">IRT</span></i><span style="font-family:Verdana;">) including explanations of cosmological relevance, the </span><i><span style="font-family:Verdana;">ε</span></i><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">infinity theory, superconductivity, and the </span><i><span style="font-family:Verdana;">Tammes</span></i><span style="font-family:Verdana;"> problem of the largest diameter of </span><i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;"> non-overlapping circles on the surface of a sphere with its connection to viral morphology and crystallography. Finally, </span><i><span style="font-family:Verdana;">Fibo</span><span style="font-family:Verdana;">nacci</span></i><span style="font-family:Verdana;"> anyons proposed for topological quantum</span><span style="font-family:Verdana;"> computation (</span><i><span style="font-family:Verdana;">TQC</span></i><span style="font-family:Verdana;">) were briefly described in comparison to the recently formulated reverse </span><i><span style="font-family:Verdana;">Fibonacci</span></i><span style="font-family:Verdana;"> approach using the </span><span style="font-family:Verdana;"><em>Jani</em></span></s
基金BBSRC (332/C19286, BB/J005959/1)Leverhulme Trust Grants (F/00 382/G) to CH
文摘The endoplasmic reticulum forms the first compart- ment in a series of organelles which comprise the secretory pathway, it takes the form of an extremely dynamic and pleomorphic membrane-bounded network of tubules and cisternae which have numerous different cellular functions. In this review, we discuss the nature of endoplasmic reticulum structure and dynamics, its relationship with closely associated organelles, and its possible function as a highway for the distribution and delivery of a diverse range of structures from metabolic complexes to viral particles.
