Green fluorescent protein (GFP) fused to the F-actin binding domain of mouse talin labels the actin cytoskeleton in the living generative and sperm cells of a third generation transgenic rice (Oryza sativa L.) plant, ...Green fluorescent protein (GFP) fused to the F-actin binding domain of mouse talin labels the actin cytoskeleton in the living generative and sperm cells of a third generation transgenic rice (Oryza sativa L.) plant, A005-G-T-1-2. Observations were made on pollen at four major developmental stages, viz. I. uni-nucleate microspore stage; II. early bi-cellular pollen stage; III. late bi-cellular pollen stage; and IV. tri-cellular pollen stage. At each of these developmental stages vegetative nucleus, generative nucleus/ cell, and sperm cells were seen undergoing continuous and coordinated motion and migration. These movements seemed to be influenced by associated microfilament networks existing in the pollen. Based on these observations we propose that it is the interaction between the microfilament networks (usually one existing in the central cytoplasm and another in the cortex) that controls the dynamic movement of the vegetative nucleus, generative nucleus/cell and sperm cells. Furthermore, we have also observed that there is an array of microfilaments (oriented mostly parallel to the long axis of the cell) existing in the generative and sperm cells. As far as we are aware, this is the first report showing the existence of microfilaments in living generative and sperm cells of rice pollen. The implication and significance of the existence of microfilaments in generative and sperm cells in rendering self-propelled motion of these cells in relation to their passage and movement in the pollen tube and embryo sac for fertilization were discussed.展开更多
Research and application progresses of gE gene and its encoding gE protein in PR vaccines, diagnostic technique and epidemiological investigation are summarized, which have certain reference value for comprehensive pr...Research and application progresses of gE gene and its encoding gE protein in PR vaccines, diagnostic technique and epidemiological investigation are summarized, which have certain reference value for comprehensive prevention and control of PR and gradual purification of PR in different regions.展开更多
Green fluorescent protein (GFP) fused to the F_actin binding domain of mouse talin labels the actin cytoskeleton in the immature pollen of stable transformed rice (Oryza sativa L.) plants. Actin microfilaments could b...Green fluorescent protein (GFP) fused to the F_actin binding domain of mouse talin labels the actin cytoskeleton in the immature pollen of stable transformed rice (Oryza sativa L.) plants. Actin microfilaments could be visualized only in the late_developmental stage of the immature pollen. During this developmental stage, microfilaments, initially composed of very short fibrils, develop into a very complex and novel network that sometimes totally and sometimes partially encloses the vegetative nucleus and the spherical shaped generative cell in the central cytoplasm of the immature pollen. The behavior of the actin microfilamentous structure throughout the late_developmental stage of the immature pollen is extremely dynamic, and the likelihood of this structure in generating forces for vegetative nucleus and generative cell movement in the immature pollen has been discussed. No actin filaments were visualized in the spherical generative cells.展开更多
文摘Green fluorescent protein (GFP) fused to the F-actin binding domain of mouse talin labels the actin cytoskeleton in the living generative and sperm cells of a third generation transgenic rice (Oryza sativa L.) plant, A005-G-T-1-2. Observations were made on pollen at four major developmental stages, viz. I. uni-nucleate microspore stage; II. early bi-cellular pollen stage; III. late bi-cellular pollen stage; and IV. tri-cellular pollen stage. At each of these developmental stages vegetative nucleus, generative nucleus/ cell, and sperm cells were seen undergoing continuous and coordinated motion and migration. These movements seemed to be influenced by associated microfilament networks existing in the pollen. Based on these observations we propose that it is the interaction between the microfilament networks (usually one existing in the central cytoplasm and another in the cortex) that controls the dynamic movement of the vegetative nucleus, generative nucleus/cell and sperm cells. Furthermore, we have also observed that there is an array of microfilaments (oriented mostly parallel to the long axis of the cell) existing in the generative and sperm cells. As far as we are aware, this is the first report showing the existence of microfilaments in living generative and sperm cells of rice pollen. The implication and significance of the existence of microfilaments in generative and sperm cells in rendering self-propelled motion of these cells in relation to their passage and movement in the pollen tube and embryo sac for fertilization were discussed.
基金Supported by Natural Science Foundation of Shandong Province(ZR2014CQ012)
文摘Research and application progresses of gE gene and its encoding gE protein in PR vaccines, diagnostic technique and epidemiological investigation are summarized, which have certain reference value for comprehensive prevention and control of PR and gradual purification of PR in different regions.
文摘Green fluorescent protein (GFP) fused to the F_actin binding domain of mouse talin labels the actin cytoskeleton in the immature pollen of stable transformed rice (Oryza sativa L.) plants. Actin microfilaments could be visualized only in the late_developmental stage of the immature pollen. During this developmental stage, microfilaments, initially composed of very short fibrils, develop into a very complex and novel network that sometimes totally and sometimes partially encloses the vegetative nucleus and the spherical shaped generative cell in the central cytoplasm of the immature pollen. The behavior of the actin microfilamentous structure throughout the late_developmental stage of the immature pollen is extremely dynamic, and the likelihood of this structure in generating forces for vegetative nucleus and generative cell movement in the immature pollen has been discussed. No actin filaments were visualized in the spherical generative cells.
文摘目的:探讨幽门螺旋杆菌细胞毒素相关基因A(cytotoxin associated gene A,CagA)与胃黏膜中TET2(ten-eleventranslocation 2)蛋白表达的关系,以及TET2在CagA致癌过程中可能的作用。方法:Real-time PCR检测人胃黏膜上皮细胞株GES-1和胃癌细胞株MGC-803中TET2 mRNA的表达水平,细胞免疫染色法检测TET2蛋白的细胞定位及表达。将pEGFP-CagA通过脂质体介导转染GES-1细胞,用200μmol/L H2O2处理GES-1细胞建立氧化应激模型,流式细胞仪检测细胞中活性氧(reactive oxygen species,ROS)和细胞周期的变化。结果:TET2 mRNA在GES-1细胞的表达水平低于胃癌MGC-803细胞(1.00±0.08 vs 1.68±0.07,P<0.05),TET2蛋白在GES-1细胞表达水平低于胃癌MGC-803细胞(8.09±3.57 vs14.60±2.31,P<0.05)。与阴性对照组pEGFP-N1相比,pEGFP-CagA转染组GES-1细胞中TET2 mRNA表达水平升高(1.00±0.04 vs 0.06±0.00,P<0.05),TET2蛋白表达水平也升高(16.45±4.40 vs 10.82±3.39,P<0.05),ROS积累水平升高(18.39±4.52 vs 15.31±4.40,P<0.05),细胞周期检测出现明显的凋亡峰。氧化应激(H2O2处理)模型中GES-1细胞与空白对照GES-1细胞相比,TET2 mRNA水平升高(1.44±0.02 vs 1.00±0.04,P<0.05),TET2蛋白表达水平增高(15.72±4.52vs 11.74±4.34,P<0.05)。结论:幽门螺旋杆菌毒力因子CagA可诱导GES-1细胞ROS增高和细胞周期的失衡,氧化应激可以诱导TET2表达上调,TET2可能参与CagA的致癌过程。
