Formins are well-known regulators that participate in the organization of the actin cytoskeleton in organisms. The Arabidopsis thaliana L. genome encodes 21 formins, which can be divided into two distinct subfamilies....Formins are well-known regulators that participate in the organization of the actin cytoskeleton in organisms. The Arabidopsis thaliana L. genome encodes 21 formins, which can be divided into two distinct subfamilies. However, type II formins have to date been less well characterized. Here, we cloned a type II formin, AtFH16, and characterized its biochemical activities on actin and microtubule dynamics. The results show that the FH1 FH2 structure of AtFH16 cannot nucleate actin polymerization efficiently, but can bind and bundle microfilaments. AtFH16 FHIFH2 is also able to bind and bundle microtubules, and preferentially binds microtubules over microfilaments in vitro, in addition, AtFH16 FHIFH2 co-localizes with microtubules in onion epidermal cells, indicating a higher binding affinity of AtFH16 FHIFH2 for microtubules rather than microfilaments in vivo. In conclusion, AtFH16 is able to interact with both microfilaments and microtubules, suggesting that AtFH16 probably functions as a bifunctional protein, and may thus participate in plant cellular processes.展开更多
Chloroplast movement is essential for plants to survive under various environmental light conditions. Photo- tropins--plant-specific blue-light-activated receptor kinases--mediate the response by perceiving light inte...Chloroplast movement is essential for plants to survive under various environmental light conditions. Photo- tropins--plant-specific blue-light-activated receptor kinases--mediate the response by perceiving light intensity and direction. Recently, novel chloroplast actin （cp-actin） filaments have been identified as playing a pivotal role in the directional chloroplast photorelocation movement. Encouraging progress has recently been made in this field of research through molecular genetics and cell biological analyses. This review describes factors that have been identified as being involved in chloroplast movement and their roles in the regulation of cp-actin filaments, thus providing a basis for reflection on their biochemical activities and functions.展开更多
BACKGROUND: In experimental acute pancreatitis, a large amount of reactive oxygen species are produced, and in turn cytoskeletal changes may be induced in pancreatic tissue. These changes contribute to an imbalance of...BACKGROUND: In experimental acute pancreatitis, a large amount of reactive oxygen species are produced, and in turn cytoskeletal changes may be induced in pancreatic tissue. These changes contribute to an imbalance of digestive enzyme segregation, transport, exocytosis and activation, resulting in cell injury. In this study, we assessed the effects of chondroitin sulfate (CS) on attenuation of oxidative damage and protection of F-actin in rats with acute necrotizing pancreatitis (ANP). METHODS: Ninety male Wistar rats were divided randomly into three groups. Group A was infused with 5% sodium taurocholate; group B was treated with CS; and group C served as control. Rats from the three groups were killed at 1, 3 or 8 hours. The levels were measured of malonyl dialdehyde (MDA), total superoxide dismutase (SOD), glutathione synthetase (GSH), serum amylase (SAM) and adenosine triphosphate (ATP). F-actin immunostained with rhodamine-phalloidin was analyzed using a confocal laser scanning system and the content of F-actin protein was determined. RESULTS: The levels of SAM increased in groups A and B, whereas the levels of GSH, SOD and ATP in group A decreased markedly during pancreatitis, and MDA increased significantly. The levels of GSH, SOD and ATP in group B were higher than those in group A, but the level of MDA was lower than in group A. At the same time, ANP resulted in early disruption of the cytoskeleton with dramatic changes and a loss of F-actin. Administration of CS moderated the damage to the actin cytoskeleton. CONCLUSIONS: Retrograde infusion of sodium taurocholate via the pancreatic duct may produce pancreatic necrosis and a marked increase in serum amylase activity, induce a severe depletion of ATP level, prime lipid peroxidation, and damage F-actin. Treatment with CS can ameliorate pancreatic cell conditions, limit cell membrane peroxidation, protect F-actin, and attenuate pancreatitis.展开更多
Pollen grains of Pinus thunbergii Parl. （Japanese black pine） were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin c...Pollen grains of Pinus thunbergii Parl. （Japanese black pine） were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.展开更多
Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mech...Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mechanism.To determine the role of Tprn in hearing,we generated Tprn-null mice by clustered regularly interspaced short palindromic repeat/Cas9 genome-editing technology from a CBA/CaJ background.We observed significant hearing loss and progressive degeneration of stereocilia in the outer hair cells of Tprn-null mice starting from postnatal day 30.Transmission electron microscopy images of stereociliary bundles in the mutant mice showed some stereociliary rootlets with curved shafts.The central cores of the stereociliary rootlets possessed hollow structures with surrounding loose peripheral dense rings.Radixin,a protein expressed at stereocilia tapering,was abnormally dispersed along the stereocilia shafts in Tprn-null mice.The expression levels of radixin andβ-actin significantly decreased.We propose that Tprn is critical to the retention of the integrity of the stereociliary rootlet.Loss of Tprn in Tprn-null mice caused the disruption of the stereociliary rootlet,which resulted in damage to stereociliary bundles and hearing impairments.The generated Tprn-null mice are ideal models of human hereditary deafness DFNB79.展开更多
We evaluated the cellular structure changes after continuous use of ripasudil hydrochloride hydrate in rabbit eyes which might affect its own efficacy and adverse effects. Two pigmented Dutch rabbits and 1 Japanese wh...We evaluated the cellular structure changes after continuous use of ripasudil hydrochloride hydrate in rabbit eyes which might affect its own efficacy and adverse effects. Two pigmented Dutch rabbits and 1 Japanese white rabbit were instilled with 0.4% ripasudil hydrochloride hydrate to the left eye twice daily. The right eye was observed as the control. Both eyes of all 3 rabbits were then enucleated for histopathologic examination by light and electron microscope at 1 mo in 1 of the pigmented Dutch rabbits, 3 mo in the other pigmented Dutch rabbit, and in the Japanese white rabbit after instillation. Microscopic observations showed increase intercellular space in trabecular meshwork, ciliary body, and iris stoma, increase pigmented granule number and size in iris epithelial cells, and decrease actin filament in iris muscle fiber cells. Consequently, ripasudil hydrochloride hydrate decreases the intraocular pressure by improving the conventional outflow and may also facilitate the unconventional outflow via intercellular space widening without serious side effects.展开更多
基金supported by the National Natural Science Foundation of China (31130005)the National Basic Research Program of China (2013CB126902) to H. R.
文摘Formins are well-known regulators that participate in the organization of the actin cytoskeleton in organisms. The Arabidopsis thaliana L. genome encodes 21 formins, which can be divided into two distinct subfamilies. However, type II formins have to date been less well characterized. Here, we cloned a type II formin, AtFH16, and characterized its biochemical activities on actin and microtubule dynamics. The results show that the FH1 FH2 structure of AtFH16 cannot nucleate actin polymerization efficiently, but can bind and bundle microfilaments. AtFH16 FHIFH2 is also able to bind and bundle microtubules, and preferentially binds microtubules over microfilaments in vitro, in addition, AtFH16 FHIFH2 co-localizes with microtubules in onion epidermal cells, indicating a higher binding affinity of AtFH16 FHIFH2 for microtubules rather than microfilaments in vivo. In conclusion, AtFH16 is able to interact with both microfilaments and microtubules, suggesting that AtFH16 probably functions as a bifunctional protein, and may thus participate in plant cellular processes.
文摘Chloroplast movement is essential for plants to survive under various environmental light conditions. Photo- tropins--plant-specific blue-light-activated receptor kinases--mediate the response by perceiving light intensity and direction. Recently, novel chloroplast actin （cp-actin） filaments have been identified as playing a pivotal role in the directional chloroplast photorelocation movement. Encouraging progress has recently been made in this field of research through molecular genetics and cell biological analyses. This review describes factors that have been identified as being involved in chloroplast movement and their roles in the regulation of cp-actin filaments, thus providing a basis for reflection on their biochemical activities and functions.
文摘BACKGROUND: In experimental acute pancreatitis, a large amount of reactive oxygen species are produced, and in turn cytoskeletal changes may be induced in pancreatic tissue. These changes contribute to an imbalance of digestive enzyme segregation, transport, exocytosis and activation, resulting in cell injury. In this study, we assessed the effects of chondroitin sulfate (CS) on attenuation of oxidative damage and protection of F-actin in rats with acute necrotizing pancreatitis (ANP). METHODS: Ninety male Wistar rats were divided randomly into three groups. Group A was infused with 5% sodium taurocholate; group B was treated with CS; and group C served as control. Rats from the three groups were killed at 1, 3 or 8 hours. The levels were measured of malonyl dialdehyde (MDA), total superoxide dismutase (SOD), glutathione synthetase (GSH), serum amylase (SAM) and adenosine triphosphate (ATP). F-actin immunostained with rhodamine-phalloidin was analyzed using a confocal laser scanning system and the content of F-actin protein was determined. RESULTS: The levels of SAM increased in groups A and B, whereas the levels of GSH, SOD and ATP in group A decreased markedly during pancreatitis, and MDA increased significantly. The levels of GSH, SOD and ATP in group B were higher than those in group A, but the level of MDA was lower than in group A. At the same time, ANP resulted in early disruption of the cytoskeleton with dramatic changes and a loss of F-actin. Administration of CS moderated the damage to the actin cytoskeleton. CONCLUSIONS: Retrograde infusion of sodium taurocholate via the pancreatic duct may produce pancreatic necrosis and a marked increase in serum amylase activity, induce a severe depletion of ATP level, prime lipid peroxidation, and damage F-actin. Treatment with CS can ameliorate pancreatic cell conditions, limit cell membrane peroxidation, protect F-actin, and attenuate pancreatitis.
基金National Science Foundation of Fujian Province of China(No.B0610031)Science and Technology Program of Put-Jan Municipality of China(No.2006N17)
文摘Pollen grains of Pinus thunbergii Parl. （Japanese black pine） were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.
文摘Tprn encodes the taperin protein,which is concentrated in the tapered region of hair cell stereocilia in the inner ear.In humans,TPRN mutations cause autosomal recessive nonsyndromic deafness(DFNB79)by an unknown mechanism.To determine the role of Tprn in hearing,we generated Tprn-null mice by clustered regularly interspaced short palindromic repeat/Cas9 genome-editing technology from a CBA/CaJ background.We observed significant hearing loss and progressive degeneration of stereocilia in the outer hair cells of Tprn-null mice starting from postnatal day 30.Transmission electron microscopy images of stereociliary bundles in the mutant mice showed some stereociliary rootlets with curved shafts.The central cores of the stereociliary rootlets possessed hollow structures with surrounding loose peripheral dense rings.Radixin,a protein expressed at stereocilia tapering,was abnormally dispersed along the stereocilia shafts in Tprn-null mice.The expression levels of radixin andβ-actin significantly decreased.We propose that Tprn is critical to the retention of the integrity of the stereociliary rootlet.Loss of Tprn in Tprn-null mice caused the disruption of the stereociliary rootlet,which resulted in damage to stereociliary bundles and hearing impairments.The generated Tprn-null mice are ideal models of human hereditary deafness DFNB79.
基金Supported by Kitasato University Research Grant for Young Researchers (2018)
文摘We evaluated the cellular structure changes after continuous use of ripasudil hydrochloride hydrate in rabbit eyes which might affect its own efficacy and adverse effects. Two pigmented Dutch rabbits and 1 Japanese white rabbit were instilled with 0.4% ripasudil hydrochloride hydrate to the left eye twice daily. The right eye was observed as the control. Both eyes of all 3 rabbits were then enucleated for histopathologic examination by light and electron microscope at 1 mo in 1 of the pigmented Dutch rabbits, 3 mo in the other pigmented Dutch rabbit, and in the Japanese white rabbit after instillation. Microscopic observations showed increase intercellular space in trabecular meshwork, ciliary body, and iris stoma, increase pigmented granule number and size in iris epithelial cells, and decrease actin filament in iris muscle fiber cells. Consequently, ripasudil hydrochloride hydrate decreases the intraocular pressure by improving the conventional outflow and may also facilitate the unconventional outflow via intercellular space widening without serious side effects.
