Chloroplasts are plant-specific organelles that evolved from endosymbiotic cyanobacteria. They divide through binary fission. Selection of the chloroplast division site is pivotal for the symmetric chloroplast divisio...Chloroplasts are plant-specific organelles that evolved from endosymbiotic cyanobacteria. They divide through binary fission. Selection of the chloroplast division site is pivotal for the symmetric chloroplast division. In E. coli, positioning of the division site at the midpoint of the cell is regulated by dynamic oscillation of the Min system, which includes MinC, MinD and MinE. Homologs of MinD and MinE in plants are involved in chloroplast division. The homolog of MinC still has not been identified in higher plants. However, an FtsZ-like protein, ARC3, was found to be involved in chloroplast division site positioning. Here, we report that chloroplast division site positioning 1 （AtCDP1） is a novel chloroplast division protein involved in chloroplast division site placement in Arabidopsis. AtCDP1 was discovered by screening an Arabidopsis cDNA expression library in bacteria for colonies with a cell division phenotype. AtCDP1 is exclusively expressed in young green tissues in Arabidopsis. Elongated chloroplasts with multiple division sites were observed in the loss-of-function cdpl mutant. Overexpression of AtCDP1 caused a chloroplast division phenotype too. Protein interaction assays suggested that AtCDP1 may mediate the chloroplast division site positioning through the interaction with ARC3. Overall, our results indicate that AtCDP1 is a novel component of the chloroplast division site positioning system, and the working mechanism of this system is different from that of the traditional MinCDE system in prokaryotic cells.展开更多
In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for ...In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. Key words：展开更多
OBJECTIVE To evaluate core needle biopsy (CNB) as a mini-mally invasive method to examine breast lesions and discuss theclinical significance of subsequent immunohistochemistry (IHC)analysis.METHODS The clinical data ...OBJECTIVE To evaluate core needle biopsy (CNB) as a mini-mally invasive method to examine breast lesions and discuss theclinical significance of subsequent immunohistochemistry (IHC)analysis.METHODS The clinical data and pathological results of 235 pa-tients with breast lesions, who received CNB before surgery, wereanalyzed and compared. Based on the results of CNB done beforesurgery, 87 out of 204 patients diagnosed as invasive carcinomawere subjected to immunodetection for p53, c-erbB-2, ER and PR.The morphological change of cancer tissues in response to chemo-therapy was also evaluated.RESULTS In total of 235 cases receiving CNB examination, 204were diagnosed as invasive carcinoma, reaching a 100% consistentrate with the surgical diagnosis. Sixty percent of the cases diag-nosed as non-invasive carcinoma by CNB was identified to havethe presence of invading elements in surgical specimens, and simi-larly, 50% of the cases diagnosed as atypical ductal hyperplasia byCNB was confirmed to be carcinoma by the subsequent result ofexcision biopsy. There was no significant difference between theCNB biopsy and regular surgical samples in positive rate of im-munohistochemistry analysis (p53, c-erbB-2, ER and PR; P >0.05).However, there was significant difference in the expression rate ofp53 and c-erbB-2 between the cases with and without morphologi-cal change in response to chemotherapy (P < 0.05). In most caseswith p53 and c-erbB-2 positive, there was no obvious morphologi-cal change after chemotherapy.CONCLUSION CNB is a cost-effective diagnostic method withminimal invasion for breast lesions, although it still has some limi-tations. Immunodetection on CNB tissue is expected to have greatsignificance in clinical applications.展开更多
基金Acknowledgment We thank the Arabidopsis Biological Resource Center （Ohio State University, Columbus） for providing the Arabidopsis seeds and the editor for was supported by careful reading of the manuscript. This work the National Natural Science Foundation of China （30470879） and Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality to He, and National Natural Science Foundation of China （30500288） and Science and Technology Development Program of Beijing Municipal Education Committee grant （KM200610028010） of Beijing Education Committee to Hu.
文摘Chloroplasts are plant-specific organelles that evolved from endosymbiotic cyanobacteria. They divide through binary fission. Selection of the chloroplast division site is pivotal for the symmetric chloroplast division. In E. coli, positioning of the division site at the midpoint of the cell is regulated by dynamic oscillation of the Min system, which includes MinC, MinD and MinE. Homologs of MinD and MinE in plants are involved in chloroplast division. The homolog of MinC still has not been identified in higher plants. However, an FtsZ-like protein, ARC3, was found to be involved in chloroplast division site positioning. Here, we report that chloroplast division site positioning 1 （AtCDP1） is a novel chloroplast division protein involved in chloroplast division site placement in Arabidopsis. AtCDP1 was discovered by screening an Arabidopsis cDNA expression library in bacteria for colonies with a cell division phenotype. AtCDP1 is exclusively expressed in young green tissues in Arabidopsis. Elongated chloroplasts with multiple division sites were observed in the loss-of-function cdpl mutant. Overexpression of AtCDP1 caused a chloroplast division phenotype too. Protein interaction assays suggested that AtCDP1 may mediate the chloroplast division site positioning through the interaction with ARC3. Overall, our results indicate that AtCDP1 is a novel component of the chloroplast division site positioning system, and the working mechanism of this system is different from that of the traditional MinCDE system in prokaryotic cells.
基金Acknowledgements This work was supported by the Hi-Tech Research and Development Program of China under Grant No.2007AA01Z407 the Co-Funding Project of Beijing Municipal education Commission under Grant No.JD100060630+3 种基金 National Foundation Research Project the National Natural Science Foundation Project under Grant No. 61170295 the Project of Aeronautical Science Foundation of China under Caant No.2011ZC51024 and the Fundamental Research Funds for the Central Universities.
文摘In the traditional Intemet Protocol （IP） architecture, there is an overload of IP sermntic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks （MANETs）. To improve scalability, a routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector （TLDV）. The hard core of this routing method is the identifier/locator split by the Distributed Hash Table （DHT） method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes, kocator space ks organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform Results show that TLDV has better scalability. Key words：
文摘OBJECTIVE To evaluate core needle biopsy (CNB) as a mini-mally invasive method to examine breast lesions and discuss theclinical significance of subsequent immunohistochemistry (IHC)analysis.METHODS The clinical data and pathological results of 235 pa-tients with breast lesions, who received CNB before surgery, wereanalyzed and compared. Based on the results of CNB done beforesurgery, 87 out of 204 patients diagnosed as invasive carcinomawere subjected to immunodetection for p53, c-erbB-2, ER and PR.The morphological change of cancer tissues in response to chemo-therapy was also evaluated.RESULTS In total of 235 cases receiving CNB examination, 204were diagnosed as invasive carcinoma, reaching a 100% consistentrate with the surgical diagnosis. Sixty percent of the cases diag-nosed as non-invasive carcinoma by CNB was identified to havethe presence of invading elements in surgical specimens, and simi-larly, 50% of the cases diagnosed as atypical ductal hyperplasia byCNB was confirmed to be carcinoma by the subsequent result ofexcision biopsy. There was no significant difference between theCNB biopsy and regular surgical samples in positive rate of im-munohistochemistry analysis (p53, c-erbB-2, ER and PR; P >0.05).However, there was significant difference in the expression rate ofp53 and c-erbB-2 between the cases with and without morphologi-cal change in response to chemotherapy (P < 0.05). In most caseswith p53 and c-erbB-2 positive, there was no obvious morphologi-cal change after chemotherapy.CONCLUSION CNB is a cost-effective diagnostic method withminimal invasion for breast lesions, although it still has some limi-tations. Immunodetection on CNB tissue is expected to have greatsignificance in clinical applications.
