蛋白质Tat转运系统不同于细菌中普遍存在的Sec转运系统 ,而与植物叶绿体中蛋白质转运的ΔpH依赖系统相似 .通过Tat系统转运的蛋白质底物含有特征性的双精氨酸保守序列核心S/T R R x F L K的信号肽 ,其h区的疏水性低 ,c区有由高赖氨酸、...蛋白质Tat转运系统不同于细菌中普遍存在的Sec转运系统 ,而与植物叶绿体中蛋白质转运的ΔpH依赖系统相似 .通过Tat系统转运的蛋白质底物含有特征性的双精氨酸保守序列核心S/T R R x F L K的信号肽 ,其h区的疏水性低 ,c区有由高赖氨酸、高精氨酸构成的避开Sec系统信号 ,信号肽和成熟蛋白质的组成对蛋白质的转运都有影响 .TatA、TatB、TatC和TatE四种蛋白质参与了大肠杆菌的Tat转运系统 .被转运的底物蛋白质绝大多数为与细菌厌氧呼吸有关的含氧化还原辅因子的酶 ,并以折叠形式转运 .展开更多
分泌系统对于具有特殊细胞被膜结构的分枝杆菌,尤其是致病性分枝杆菌的存活和毒力非常重要.不少重要的致病因子或存活因子都通过特定的分泌系统进入环境,包括宿主体内.本文从分泌系统的基因、结构组成、分泌底物、转运机制及其与致病菌...分泌系统对于具有特殊细胞被膜结构的分枝杆菌,尤其是致病性分枝杆菌的存活和毒力非常重要.不少重要的致病因子或存活因子都通过特定的分泌系统进入环境,包括宿主体内.本文从分泌系统的基因、结构组成、分泌底物、转运机制及其与致病菌毒力的关系等几个方面介绍了分枝杆菌(mycobacteria)通用型分泌系统(general secretion pathway,SecA1)、替代型分泌系统(accessory Sec system,SecA2)、双精氨酸分泌系统(twin-arginine translocation,Tat)和Ⅶ型分泌系统(typeⅦsecretion systems,T7S system or ESX)4种分泌系统,并重点分析了Tat分泌系统.这些知识有利于从分泌系统及其底物的角度揭示结核分枝杆菌等胞内致病菌存活和逃避宿主免疫的机理,将为研发新的结核病控制措施提供依据.展开更多
Quantitative trait loci (QTLs) for chlorophyll content of a rice leaf weremapped on to the molecular marker linkage map of a double-haploid (DH) population derived from across between two rice varieties 'IR64'...Quantitative trait loci (QTLs) for chlorophyll content of a rice leaf weremapped on to the molecular marker linkage map of a double-haploid (DH) population derived from across between two rice varieties 'IR64' and 'Azucena' in both nutrient solutionand soil cultureexperiments to detect rice nitrogen nutrition status under low N stress A chlorophyll meter was usedto measure the soil plant analysis development (SPAD) value of the topmost fully expanded leaf asthe index of chlorophyll content thatexpressed nitrogen status in rice plants. Totally 3 QTLs forSPAD values, two on chromosome 3 located at interval RG179-CDO337 and RG348-RZ329, respectively, andone on chromosome 10 at interval RZ500-RG134, were detected under stressed conditions of low N inthe soil and/or nutrient solution culture experiments. One QTL located at interval RG179-GDO337 onchromosome 3 associated with a relative change in SPAD value from a high N level to a low N level inthe soil culture experiment was also detected.Based on the different responses to low N stressbetween the two parents, it was supposed that the QTLs identified in this study associated withnitrogen efficiency in rice at low N levels might be useful in applying marker technology to ricebreeding programs.展开更多
In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass...In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.展开更多
The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy. Some abnorm...The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy. Some abnormalities including degenerated ovary, abortive embryo sac, single fertilization, double-ovule and double-embryo and so on. were found dudng double fertilization and embryo development in IR36-Shuang. The rate of the abnormalities was 46.67% in IR36-Shuang, significantly higher than that in the control, an autotetraploid rice line IR36-4X （33.00%）. Cytological and embryonic evidences were provided for seed setting decline and the initiation of additional embryo in IR36-Shuang.展开更多
文摘蛋白质Tat转运系统不同于细菌中普遍存在的Sec转运系统 ,而与植物叶绿体中蛋白质转运的ΔpH依赖系统相似 .通过Tat系统转运的蛋白质底物含有特征性的双精氨酸保守序列核心S/T R R x F L K的信号肽 ,其h区的疏水性低 ,c区有由高赖氨酸、高精氨酸构成的避开Sec系统信号 ,信号肽和成熟蛋白质的组成对蛋白质的转运都有影响 .TatA、TatB、TatC和TatE四种蛋白质参与了大肠杆菌的Tat转运系统 .被转运的底物蛋白质绝大多数为与细菌厌氧呼吸有关的含氧化还原辅因子的酶 ,并以折叠形式转运 .
文摘分泌系统对于具有特殊细胞被膜结构的分枝杆菌,尤其是致病性分枝杆菌的存活和毒力非常重要.不少重要的致病因子或存活因子都通过特定的分泌系统进入环境,包括宿主体内.本文从分泌系统的基因、结构组成、分泌底物、转运机制及其与致病菌毒力的关系等几个方面介绍了分枝杆菌(mycobacteria)通用型分泌系统(general secretion pathway,SecA1)、替代型分泌系统(accessory Sec system,SecA2)、双精氨酸分泌系统(twin-arginine translocation,Tat)和Ⅶ型分泌系统(typeⅦsecretion systems,T7S system or ESX)4种分泌系统,并重点分析了Tat分泌系统.这些知识有利于从分泌系统及其底物的角度揭示结核分枝杆菌等胞内致病菌存活和逃避宿主免疫的机理,将为研发新的结核病控制措施提供依据.
基金Project supported by the National Natural Science Foundation of China (No. 30070443).
文摘Quantitative trait loci (QTLs) for chlorophyll content of a rice leaf weremapped on to the molecular marker linkage map of a double-haploid (DH) population derived from across between two rice varieties 'IR64' and 'Azucena' in both nutrient solutionand soil cultureexperiments to detect rice nitrogen nutrition status under low N stress A chlorophyll meter was usedto measure the soil plant analysis development (SPAD) value of the topmost fully expanded leaf asthe index of chlorophyll content thatexpressed nitrogen status in rice plants. Totally 3 QTLs forSPAD values, two on chromosome 3 located at interval RG179-CDO337 and RG348-RZ329, respectively, andone on chromosome 10 at interval RZ500-RG134, were detected under stressed conditions of low N inthe soil and/or nutrient solution culture experiments. One QTL located at interval RG179-GDO337 onchromosome 3 associated with a relative change in SPAD value from a high N level to a low N level inthe soil culture experiment was also detected.Based on the different responses to low N stressbetween the two parents, it was supposed that the QTLs identified in this study associated withnitrogen efficiency in rice at low N levels might be useful in applying marker technology to ricebreeding programs.
基金This work was financially supported by Project of Scientific Innova-tion, Chinese Academy of Sciences (ZKCX2-211).
文摘In order to improve production and breed new broods of bay scallop Argopecten irradians irradians, different-colored orange, purple and white lines were established by two mating methods of self-fertilization and mass spawning at a commercial scallop hatchery in spring, 2002. And then larval growth and survival of different lines was compared to test whether there is a relationship between shell color and growth and survival at early developmental stage. Both growth and survival have no significant differences among different experimental larvae of self-fertilization or mass spawning. Results are as following in the order of orange, purple and white shell stock. For the self-fertilization, growth rates of larvae were 6.174, 6.412, and 6.599 μm/d, respectively. Survival rates of larvae at Day 3 were 74.41%, 76.86%, and 82.05%; Day 6 were 49.14%, 65.63%, and 52.79%; and Day 9 were 25.06%, 20.80%, and 26.47%, respectively. For the mass spawning, the growth rates were 7.836, 7.941, and 7.878 μm/d, respectively. Survival rates at Day 3 were 93.05%, 91.95%, and 92.50%; Day 6 were 79.17%, 78.05%, and 82.50%; and Day 9 were 34.72%, 36.67%, and 38.33%, respectively. The absence of any relationship between shell color and growth and survival at the larval stage may be resulted from their common genetic basis.
基金supported by the National Science & Technology Pillar Program of China in the Tenth Five-Year Plan Period(Grant No.2001BA302B)the Education Department of Henan Province, China(Grant No.2008A208019)
文摘The process of double fertilization and the characters of embryo and endosperm development in an autotetraploid polyembryonic mutant rice IR36-Shuang were studied with a laser scanning confocal microscopy. Some abnormalities including degenerated ovary, abortive embryo sac, single fertilization, double-ovule and double-embryo and so on. were found dudng double fertilization and embryo development in IR36-Shuang. The rate of the abnormalities was 46.67% in IR36-Shuang, significantly higher than that in the control, an autotetraploid rice line IR36-4X （33.00%）. Cytological and embryonic evidences were provided for seed setting decline and the initiation of additional embryo in IR36-Shuang.
