The grass carp(Ctenopharyngodon idella) is one of the most important cultivated fish species in China.Mounting evidences suggests that microRNAs(miRNAs) may be key regulators of skeletal muscle among the grass carp,bu...The grass carp(Ctenopharyngodon idella) is one of the most important cultivated fish species in China.Mounting evidences suggests that microRNAs(miRNAs) may be key regulators of skeletal muscle among the grass carp,but the knowledge of the identity of myogenic miRNAs and role of miRNAs during skeletal muscle anabolic state remains limited.In the present study,we choose 8 miRNAs previously reported to act as muscle growth-related miRNAs for fasting-refeeding research.We investigated postprandial changes in the expression of 8 miRNAs following a single satiating meal in grass carp juveniles who had been fasting for one week and found that 7 miRNAs were sharply up-regulated within 1 or 3 h after refeeding,suggesting that they may be promising candidate miRNAs involved in a fast-response signaling system that regulates fish skeletal muscle growth.展开更多
It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth...It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.展开更多
基金Foundation items： This study was supported by the National Natural Science Foundation of China （31230076 31340054）, the Natural Science Foundation of Hunan province （14JJ2135）and the State Key Laboratory of Freshwater Ecology and Biotechnology （2012FB01 ）
文摘The grass carp(Ctenopharyngodon idella) is one of the most important cultivated fish species in China.Mounting evidences suggests that microRNAs(miRNAs) may be key regulators of skeletal muscle among the grass carp,but the knowledge of the identity of myogenic miRNAs and role of miRNAs during skeletal muscle anabolic state remains limited.In the present study,we choose 8 miRNAs previously reported to act as muscle growth-related miRNAs for fasting-refeeding research.We investigated postprandial changes in the expression of 8 miRNAs following a single satiating meal in grass carp juveniles who had been fasting for one week and found that 7 miRNAs were sharply up-regulated within 1 or 3 h after refeeding,suggesting that they may be promising candidate miRNAs involved in a fast-response signaling system that regulates fish skeletal muscle growth.
文摘It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.
