Genetic variation of ten Norway spruce (Picea abies (L.) Karst.) clones regarding their decay resistance against brown rot fungi, as well as physical and chemical properties of clones were investigated. 31- year-old s...Genetic variation of ten Norway spruce (Picea abies (L.) Karst.) clones regarding their decay resistance against brown rot fungi, as well as physical and chemical properties of clones were investigated. 31- year-old spruce clones: 26, 31, A10, A15, A7, B10, B15, B6, V7, V9 were selected across Latvia. The stem diameters of spruce clones varied between 13.0 and 20.9 cm. The wood density of clones ranged from 361 to 443 kg/m3. Klason lignin content, depending on the clone, was between 27.0%-28.9%. Cellular UV microspectrophotometry of the non-infected tracheids displayed the typical lignin distribution with highest absorbance values in the cell corners (abs280 nm 0.80) and compound middle lamellae (abs280 nm 0.48), while secondary wall showed lower lignin absorbance values (abs280 nm0.29 - 0.35). The deposition of phenolic extractives in ray parenchyma and epithelial cells of resin canals were emphasized by a significantly higher UV-absorbance (abs280 nm 0.68 to 0.78) when compared to the cell wall associated lignin. The content of acetone-soluble extractives of spruce clones varied between 1.1% - 1.8%. The x-value (natural durability) for all spruce clones after exposure to C. puteana and P. placentawas >0.90 (durability class 5, not durable). Most of clones after degradation by G. trabeum had x-value > 0.90 with exception of clones B15 and V9 that showed x-value ≤ 0.90 (durability class 4, slightly durable). Natural durability of spruce clones did not correlate with stem diameter, density, content of lignin and extractives.展开更多
Knockout Brown Norway （BN） rat could be a useful disease model for human disorders,however,a failure to derive embryonic stem （ES） cells disturbs the further development of the model.In this study,we reported a ca...Knockout Brown Norway （BN） rat could be a useful disease model for human disorders,however,a failure to derive embryonic stem （ES） cells disturbs the further development of the model.In this study,we reported a case of successful derivation of the BN rat ES cells with the derivation efficiency comparable to that of Sprague Dawley （SD） rats.The BN rat ES cells expressed the key transcription factors,and were able to form embryonic bodies （EBs） when being differentiated in vitro.After injecting the BN rat ES cells into the SD rat blastocysts,high-contribution chimeric rats were generated and could survive to their adulthood.Our success in generating pluripotent rat ES cells will benefit the generation of the knockout rats in the future.展开更多
文摘Genetic variation of ten Norway spruce (Picea abies (L.) Karst.) clones regarding their decay resistance against brown rot fungi, as well as physical and chemical properties of clones were investigated. 31- year-old spruce clones: 26, 31, A10, A15, A7, B10, B15, B6, V7, V9 were selected across Latvia. The stem diameters of spruce clones varied between 13.0 and 20.9 cm. The wood density of clones ranged from 361 to 443 kg/m3. Klason lignin content, depending on the clone, was between 27.0%-28.9%. Cellular UV microspectrophotometry of the non-infected tracheids displayed the typical lignin distribution with highest absorbance values in the cell corners (abs280 nm 0.80) and compound middle lamellae (abs280 nm 0.48), while secondary wall showed lower lignin absorbance values (abs280 nm0.29 - 0.35). The deposition of phenolic extractives in ray parenchyma and epithelial cells of resin canals were emphasized by a significantly higher UV-absorbance (abs280 nm 0.68 to 0.78) when compared to the cell wall associated lignin. The content of acetone-soluble extractives of spruce clones varied between 1.1% - 1.8%. The x-value (natural durability) for all spruce clones after exposure to C. puteana and P. placentawas >0.90 (durability class 5, not durable). Most of clones after degradation by G. trabeum had x-value > 0.90 with exception of clones B15 and V9 that showed x-value ≤ 0.90 (durability class 4, slightly durable). Natural durability of spruce clones did not correlate with stem diameter, density, content of lignin and extractives.
基金supported in part by the grants from the Chinese National Basic Research Program (No 2007CB948001)the National High Technology R&D Program of China (No 2006AA02A101)Integrated Project funded by the Sixth Framework Programme (FP6) of the European Union (Contract:LSHG-CT-2005-019015)
文摘Knockout Brown Norway （BN） rat could be a useful disease model for human disorders,however,a failure to derive embryonic stem （ES） cells disturbs the further development of the model.In this study,we reported a case of successful derivation of the BN rat ES cells with the derivation efficiency comparable to that of Sprague Dawley （SD） rats.The BN rat ES cells expressed the key transcription factors,and were able to form embryonic bodies （EBs） when being differentiated in vitro.After injecting the BN rat ES cells into the SD rat blastocysts,high-contribution chimeric rats were generated and could survive to their adulthood.Our success in generating pluripotent rat ES cells will benefit the generation of the knockout rats in the future.
