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Search for a human breast cancer virus 总被引:17,自引:0,他引:17
D H Moore J Charney B Kramarsky E Y Lasfargues N H Sarkar M J Brennan J H Burrows S M Sirsat J C Paymaster A B Vaidya 《Nature》1971,229(5287):611-614
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Carlton JM Angiuoli SV Suh BB Kooij TW Pertea M Silva JC Ermolaeva MD Allen JE Selengut JD Koo HL Peterson JD Pop M Kosack DS Shumway MF Bidwell SL Shallom SJ van Aken SE Riedmuller SB Feldblyum TV Cho JK Quackenbush J Sedegah M Shoaibi A Cummings LM Florens L Yates JR Raine JD Sinden RE Harris MA Cunningham DA Preiser PR Bergman LW Vaidya AB van Lin LH Janse CJ Waters AP Smith HO White OR Salzberg SL Venter JC Fraser CM Hoffman SL Gardner MJ Carucci DJ 《Nature》2002,419(6906):512-519
Species of malaria parasite that infect rodents have long been used as models for malaria disease research. Here we report the whole-genome shotgun sequence of one species, Plasmodium yoelii yoelii, and comparative studies with the genome of the human malaria parasite Plasmodium falciparum clone 3D7. A synteny map of 2,212 P. y. yoelii contiguous DNA sequences (contigs) aligned to 14 P. falciparum chromosomes reveals marked conservation of gene synteny within the body of each chromosome. Of about 5,300 P. falciparum genes, more than 3,300 P. y. yoelii orthologues of predominantly metabolic function were identified. Over 800 copies of a variant antigen gene located in subtelomeric regions were found. This is the first genome sequence of a model eukaryotic parasite, and it provides insight into the use of such systems in the modelling of Plasmodium biology and disease. 相似文献
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Zusammenfassung Larven vonG. mellonella sind negativ phototaktisch. Der Grad der Photonegativität verändert sich während 24 h. Durch Dauerdunkel und Dauerlicht wird das phototaktische Verhalten der Larven reziprok verändert. Wahrscheinlich handelt es sich um eine endogene Photoorientierungsrhythmik.
I am grateful to Prof. Dr.G. Birukow for extending all the facilities for this work and for his kind advice. I am also indebted to the Alexander-von-Humboldt-Stiftung for award of post-doctoral fellowship. 相似文献
I am grateful to Prof. Dr.G. Birukow for extending all the facilities for this work and for his kind advice. I am also indebted to the Alexander-von-Humboldt-Stiftung for award of post-doctoral fellowship. 相似文献
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Gardner MJ Hall N Fung E White O Berriman M Hyman RW Carlton JM Pain A Nelson KE Bowman S Paulsen IT James K Eisen JA Rutherford K Salzberg SL Craig A Kyes S Chan MS Nene V Shallom SJ Suh B Peterson J Angiuoli S Pertea M Allen J Selengut J Haft D Mather MW Vaidya AB Martin DM Fairlamb AH Fraunholz MJ Roos DS Ralph SA McFadden GI Cummings LM Subramanian GM Mungall C Venter JC Carucci DJ Hoffman SL Newbold C Davis RW Fraser CM Barrell B 《Nature》2002,419(6906):498-511
The parasite Plasmodium falciparum is responsible for hundreds of millions of cases of malaria, and kills more than one million African children annually. Here we report an analysis of the genome sequence of P. falciparum clone 3D7. The 23-megabase nuclear genome consists of 14 chromosomes, encodes about 5,300 genes, and is the most (A + T)-rich genome sequenced to date. Genes involved in antigenic variation are concentrated in the subtelomeric regions of the chromosomes. Compared to the genomes of free-living eukaryotic microbes, the genome of this intracellular parasite encodes fewer enzymes and transporters, but a large proportion of genes are devoted to immune evasion and host-parasite interactions. Many nuclear-encoded proteins are targeted to the apicoplast, an organelle involved in fatty-acid and isoprenoid metabolism. The genome sequence provides the foundation for future studies of this organism, and is being exploited in the search for new drugs and vaccines to fight malaria. 相似文献
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The origin of all mitochondria can be traced to the symbiotic arrangement that resulted in the emergence of eukaryotes in a world that was exclusively populated by prokaryotes. This arrangement, however, has been in continuous genetic flux: the varying degrees of gene loss and transfer from the mitochondrial genome in different eukaryotic lineages seem to signify an ongoing 'conflict' between the host and the symbiont. Eukaryotic parasites belonging to the phylum Apicomplexa provide an excellent example to support this view. These organisms contain the smallest mitochondrial genomes known, with an organization that differs among various genera; one genus, Cryptosporidium, seems to have lost the entire mitochondrial genome. Here we show that erythrocytic stages of the human malaria parasite Plasmodium falciparum seem to maintain an active mitochondrial electron transport chain to serve just one metabolic function: regeneration of ubiquinone required as the electron acceptor for dihydroorotate dehydrogenase, an essential enzyme for pyrimidine biosynthesis. Transgenic P. falciparum parasites expressing Saccharomyces cerevisiae dihydroorotate dehydrogenase, which does not require ubiquinone as an electron acceptor, were completely resistant to inhibitors of mitochondrial electron transport. Maintenance of mitochondrial membrane potential, however, was essential in these parasites, as indicated by their hypersensitivity to proguanil, a drug that collapsed the membrane potential in the presence of electron transport inhibitors. Thus, acquisition of just one enzyme can render mitochondrial electron transport nonessential in erythrocytic stages of P. falciparum. 相似文献
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The rapid migration of intestinal epithelial cells (IEC) is important for the healing of mucosal wounds. We have previously
shown that polyamine depletion inhibits migration of IEC-6 cells. Akt activation and its downstream target GSK-3β have been
implicated in the regulation of migration. Here we investigated the significance of elevated phosphatidylinositol 3-kinase
(PI3K)/Akt signaling on migration of polyamine-depleted cells. Polyamine-depleted cells had high Akt (Ser473) and GSK-3β (Ser9)
phosphorylation. Pretreatment with 20 μM LY294002 (PI3K inhibitor) for 30 min inhibited phosphorylation of Akt, increased
migration by activating Rac1 in polyamine-depleted IEC-6 cells, and restored the actin structure similar to that in cells
grown in control medium. Treatment of cells with a GSK-3β inhibitor (AR-A014418) altered the actin cytoskeleton and inhibited
migration, mimicking the effects of polyamine depletion. Thus, our results indicate that sustained activation of Akt in response
to polyamine depletion inhibits migration through GSK-3β and Rac1.
Received 25 August 2006; received after revision 3 October 2006; accepted 16 October 2006 相似文献
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Involvement of targeted proteolysis in plant genetic transformation by Agrobacterium 总被引:1,自引:0,他引:1
Genetic transformation of plant cells by Agrobacterium represents a unique case of trans-kingdom DNA transfer. During this process, Agrobacterium exports its transferred (T) DNA and several virulence (Vir) proteins into the host cell, within which T-DNA nuclear import is mediated by VirD2 (ref. 3) and VirE2 (ref. 4) and their host cell interactors AtKAP-alpha and VIP1 (ref. 6), whereas its integration is mediated mainly by host cell proteins. The factors involved in the uncoating of T-DNA from its cognate proteins, which occurs before integration into the host genome, are still unknown. Here, we report that VirF-one of the few known exported Vir proteins whose function in the host cell remains unknown-is involved in targeted proteolysis of VIP1 and VirE2. We show that VirF localizes to the plant cell nucleus and interacts with VIP1, a nuclear protein. VirF, which contains an F-box motif, significantly destabilizes both VIP1 and VirE2 in yeast cells. Destabilization of VIP1 in the presence of VirF was then confirmed in planta. These results suggest that VIP1 and its cognate VirE2 are specifically targeted by the VirF-containing Skp1-Cdc53-cullin-F-box complex for proteolysis. The critical role of proteasomal degradation in Agrobacterium-mediated genetic transformation was also evident from inhibition of T-DNA expression by a proteasomal inhibitor. 相似文献