应用光镜、透射电镜和扫描电镜观察,瓶囊碘泡虫Myxobolus ampullicapsulatus Zhao et al.,2008成熟孢子由孢壳、极囊和孢质3部分组成。其孢子壳面观呈梨形,缝面观呈凸透镜形,囊间突明显;2片孢壳厚而均匀且表面凹凸不平。极囊瓶形,位于...应用光镜、透射电镜和扫描电镜观察,瓶囊碘泡虫Myxobolus ampullicapsulatus Zhao et al.,2008成熟孢子由孢壳、极囊和孢质3部分组成。其孢子壳面观呈梨形,缝面观呈凸透镜形,囊间突明显;2片孢壳厚而均匀且表面凹凸不平。极囊瓶形,位于孢子前端,约占整个孢子长度的2/3;极囊壁由"暗-明"2部分组成;极丝呈双"S"形缠绕并沿极囊纵轴逆时针向上螺旋8～11圈。孢质均匀而稠密,近球形的2个胚核大小不一;孢质中除了可观察到丰富的线粒体、粗面内质网、核糖体、高尔基体、嗜碘泡等细胞器及脂滴等泡状结构外,还可于孢质中观察到有一些数目不等的球状电子致密物质,其中2个分布于极囊周围。展开更多
A new metastable β type titanium alloy called TB-13 with the combination of excellent strength and ductility was developed successfully.In order to develop a perspective on this new alloy,the influence of several com...A new metastable β type titanium alloy called TB-13 with the combination of excellent strength and ductility was developed successfully.In order to develop a perspective on this new alloy,the influence of several commonly used heat treatments on the microstructure and properties was studied.In solution-treated and quenched samples,a low-temperature aging at 480°C results in the precipitation of finerαphase.The precipitation of coarserαphase plate at higher aging temperature(560°C)leads to the increase of tensile ductility but reduction of strength.During low-temperature aging at 300°C,quite homogeneous distribution of fine isothermalωphase particles was found.The isothermalωphase provides nucleation sites forαphase during two-step aging process and makesαphase extremely fine and disperse uniformly in β matrix.Thus,TB-13 alloy is strengthened and its mechanical properties are improved.展开更多
The ultrastructures of skin chloride celis in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These devel...The ultrastructures of skin chloride celis in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride celis were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride celis of euryhaline fish gill. They lo-cate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying net-work of tubules. The degeneration of skin chloride celis is observed with development of Japanese flounder larvae. Skin chloride celis of turbot are less developmental than those of Japanese flounder in the same developmental stage.展开更多
Spionid worms of Polydora ciliata inhabit the shells of many commercially important bivalves and cause disease in molluscan aquaculture. Their sperm structure is closely related to their fertilization method. To give ...Spionid worms of Polydora ciliata inhabit the shells of many commercially important bivalves and cause disease in molluscan aquaculture. Their sperm structure is closely related to their fertilization method. To give an insight into the sperm structure and spermatogenesis, ultrastructure details of the subcellular components of germ cells during spermiogenesis of Polydora ciliata are detected by transmission electron microscopy(TEM). In P. ciliata, during spermiogenesis, chromatin is regularly arranged as dense fibrils and becomes more condensed when the nucleus elongates. Microtubules do not surround the nucleus during its elongation. The Golgi phase is characterized by the formation of proacrosomal granules within the Golgi apparatus. The proacrosomal granules fuse to form a single, spherical acrosomal vesicle that migrates to the anterior pole of the cell. At the time of nuclear condensation, mitochondria become reduced in number but increased in size, causing deep indentation at the base of the nucleus. The mid-piece has a few mitochondria. The cap phase includes the spreading of the acrosomal granule over the surface of the nucleus of the differentiating spermatid. The acrosomal phase of spermiogenesis is typically associated with changes in the shape of the nucleus, acrosome and tail. The relationship of sperm ultrastructure to spermiogenesis in spionidae species was discussed.展开更多
Controlled ecological life support systems provide food, air, water, and other basic living resources for crew members on long-duration spaceflight missions. Plants are an important basic requirement of these systems ...Controlled ecological life support systems provide food, air, water, and other basic living resources for crew members on long-duration spaceflight missions. Plants are an important basic requirement of these systems and their biological characteristics in space have very high research value. Based on experiments of spaceflight in Shenzhou 8 spacecraft and simulating microgravity effects on three-dimensional （3-D） clinostat, the biological characteristics of tomato＇s leaf cell sub-microstructure and antioxidant enzyme activities were studied and compared in this work. Results showed that leaf cell sub-microstructure of the tomato samples experiencing spaceflight had more changes than effects, and both peroxidase （POD） and superoxide dismutase （SOD） that of the samples processed by simulated microgravity activities increase obviously in both the environments.展开更多
文摘应用光镜、透射电镜和扫描电镜观察,瓶囊碘泡虫Myxobolus ampullicapsulatus Zhao et al.,2008成熟孢子由孢壳、极囊和孢质3部分组成。其孢子壳面观呈梨形,缝面观呈凸透镜形,囊间突明显;2片孢壳厚而均匀且表面凹凸不平。极囊瓶形,位于孢子前端,约占整个孢子长度的2/3;极囊壁由"暗-明"2部分组成;极丝呈双"S"形缠绕并沿极囊纵轴逆时针向上螺旋8～11圈。孢质均匀而稠密,近球形的2个胚核大小不一;孢质中除了可观察到丰富的线粒体、粗面内质网、核糖体、高尔基体、嗜碘泡等细胞器及脂滴等泡状结构外,还可于孢质中观察到有一些数目不等的球状电子致密物质,其中2个分布于极囊周围。
基金Project(2007CB613802)supported by the National Basic Research Program of ChinaProject(KP200912)supported by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China
文摘A new metastable β type titanium alloy called TB-13 with the combination of excellent strength and ductility was developed successfully.In order to develop a perspective on this new alloy,the influence of several commonly used heat treatments on the microstructure and properties was studied.In solution-treated and quenched samples,a low-temperature aging at 480°C results in the precipitation of finerαphase.The precipitation of coarserαphase plate at higher aging temperature(560°C)leads to the increase of tensile ductility but reduction of strength.During low-temperature aging at 300°C,quite homogeneous distribution of fine isothermalωphase particles was found.The isothermalωphase provides nucleation sites forαphase during two-step aging process and makesαphase extremely fine and disperse uniformly in β matrix.Thus,TB-13 alloy is strengthened and its mechanical properties are improved.
文摘The ultrastructures of skin chloride celis in cultured Japanese flounder and turbot larvae in metamorphosis, which grow in the same feeding conditions, are examined with a transmission electron microscope. These developed skin chloride celis were shaped like flattened ellipsoids and similar in morphology and ultrastructure to typical chloride celis of euryhaline fish gill. They lo-cate in the epidermis and contract with the extra and interior environment through the apical pit and narrow channels. The cytoplasm of cell is full of numerous mitochondria and a ramifying net-work of tubules. The degeneration of skin chloride celis is observed with development of Japanese flounder larvae. Skin chloride celis of turbot are less developmental than those of Japanese flounder in the same developmental stage.
基金supported by the National Key Technology Support Program (2011BAD13B05)
文摘Spionid worms of Polydora ciliata inhabit the shells of many commercially important bivalves and cause disease in molluscan aquaculture. Their sperm structure is closely related to their fertilization method. To give an insight into the sperm structure and spermatogenesis, ultrastructure details of the subcellular components of germ cells during spermiogenesis of Polydora ciliata are detected by transmission electron microscopy(TEM). In P. ciliata, during spermiogenesis, chromatin is regularly arranged as dense fibrils and becomes more condensed when the nucleus elongates. Microtubules do not surround the nucleus during its elongation. The Golgi phase is characterized by the formation of proacrosomal granules within the Golgi apparatus. The proacrosomal granules fuse to form a single, spherical acrosomal vesicle that migrates to the anterior pole of the cell. At the time of nuclear condensation, mitochondria become reduced in number but increased in size, causing deep indentation at the base of the nucleus. The mid-piece has a few mitochondria. The cap phase includes the spreading of the acrosomal granule over the surface of the nucleus of the differentiating spermatid. The acrosomal phase of spermiogenesis is typically associated with changes in the shape of the nucleus, acrosome and tail. The relationship of sperm ultrastructure to spermiogenesis in spionidae species was discussed.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2011CB710902)the National Manned Spaceflight Project of China
文摘Controlled ecological life support systems provide food, air, water, and other basic living resources for crew members on long-duration spaceflight missions. Plants are an important basic requirement of these systems and their biological characteristics in space have very high research value. Based on experiments of spaceflight in Shenzhou 8 spacecraft and simulating microgravity effects on three-dimensional （3-D） clinostat, the biological characteristics of tomato＇s leaf cell sub-microstructure and antioxidant enzyme activities were studied and compared in this work. Results showed that leaf cell sub-microstructure of the tomato samples experiencing spaceflight had more changes than effects, and both peroxidase （POD） and superoxide dismutase （SOD） that of the samples processed by simulated microgravity activities increase obviously in both the environments.
