喀斯特自然土壤中AM真菌对先锋植物根系的影响

【目的】研究丛枝菌根(Arbuscular mycorrhiza，AM)真菌在喀斯特自然土壤条件下对喀斯特先锋草本植物根系的影响。【方法】通过自然土接种AM真菌(N)、灭菌土接种AM真菌(M)及灭菌土壤对照(S)共3种土壤处理，种植喀斯特先锋植物狗尾草(Setaria viridis)、荩草(Arthraxon hispidus)、鬼针草(Bidens pilosa)及狼杷草(Bidens tripartita)，并测定它们的根系生物量、根长、根表面积、根体积、根平均直径、根尖数及根分枝数。【结果】荩草、鬼针草及狼杷草在N处理及M处理下具有较高的菌根侵染率，狗尾草的菌根侵染率较低。与S处理相比，M处理下AM真菌明显提高了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度，降低了根平均直径、比根长、比根面积及比根体积；与M处理相比，N处理明显降低了荩草、鬼针草及狼杷草的根系生物量、根长、根表面积、根体积、根尖数、根分枝数及组织密度，提高了比根长、比根面积及比根体积，但对根平均直径无明显影响。【结论】荩草、鬼针草及狼杷草具有较高菌根侵染率，能与AM真菌共生获得更加发达的根系，而自然土壤削弱了AM真菌对荩草、鬼针草及狼杷草根系生长的促进作用。     

Analysis of a sub-proteome which co-purifies with and is phosphorylated by the Golgi casein kinase

In an attempt to gain information about the identity of the Golgi apparatus casein kinase(s) (G-CK), responsible for the phosphorylation of caseins in lactating mammary gland, the proteins present in fractions enriched in G-CK activity eluted from DEAE-Sepharose and heparin-Sepharose columns were resolved by two-dimensional electrophoresis and analyzed by mass spectrometry. This led to the identification of 47 proteins altogether, none of which is a bona fide protein kinase. At least 9 of the identified proteins however, are readily phosphorylated by co-purifying G-CK activity, and 7 are physically associated with it to give supramolecular complex(es) of about 500 kDa as judged from Superdex S200 gel fitration and glycerol gradient ultracentrifugation experiments. In contrast, the apparent molecular weight of G-CK estimated from an in gel activity assay after SDSPAGE and renaturation is about 41 kDa. Many of the proteins phosphorylated by and/or associated with G-CK belong to the category of chaperonines, including HSP90, GRP-94 and −78, and various isoforms of protein disulfide isomerases, suggesting a global role of this kinase in the modulation of protein folding. Received 21 October 2005; received after revision 30 November 2005; accepted 6 December 2005 †These authors contributed equally to this work.     

Tyrosine phosphatase activity in mitochondria: presence of Shp-2 phosphatase in mitochondria

Tyrosine phosphorylation by unidentified enzymes has been observed in mitochondria, with recent evidence indicating that non-receptorial tyrosine kinases belonging to the Src family, which represent key players in several transduction pathways, are constitutively present in mitochondria. The extent of protein phosphorylation reflects a coordination balance between the activities of specific kinases and phophatases. The present study demonstrates that purified rat brain mitochondria possess endogenous tyrosine phosphatase activity. Mitochondrial phosphatases were found to be capable of dephosphorylating different exogenous substrates, including paranitrophenylphosphate, ³²P-poly(Glu-Tyr)_4:1 and ³²P-angiotensin. These activities are strongly inhibited by peroxovanadate, a well-known inhibitor of tyrosine phosphatases, but not by inhibitors of alkali or Ser/Thr phosphatases, and mainly take place in the intermembrane space and outer mitochondrial membrane. Using a combination of approaches, we identified the tyrosine phosphatase Shp-2 in mitochondria. Shp-2 plays a crucial role in a number of intracellular signalling cascades and is probably involved in several human diseases. It thus represents the first tyrosine phosphatase shown to be present in mitochondria.Received 17 May 2004; received after revision 20 July 2004; accepted 26 July 2004     

基于并行工程的产品开发过程管理的研究

并行工程采用集成化与并行化的思想来开发产品,强调在信息集成基础上的过程集成,运用工作流管理技术能够很好地达到此目的。在分析工作流管理技术的基础上,以冲压模具的开发过程为例来说明用工作流管理技术实现产品开发过程管理的     

GH220合金中碳化物相变规律

研究了合金中M_6C,M_(23)C_6及MC的晶体结构、化学组成、形态、分布及数量,它们的溶解析出规律及互相转化。