排序方式: 共有185条查询结果,搜索用时 15 毫秒
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Pozidis C Chalkiadaki A Gomez-Serrano A Stahlberg H Brown I Tampakaki AP Lustig A Sianidis G Politou AS Engel A Panopoulos NJ Mansfield J Pugsley AP Karamanou S Economou A 《The Journal of biological chemistry》2003,278(28):25816-25824
Type III protein secretion (TTS) is catalyzed by translocases that span both membranes of Gram-negative bacteria. A hydrophilic TTS component homologous to F1/V1-ATPases is ubiquitous and essential for secretion. We show that hrcN encodes the putative TTS ATPase of Pseudomonas syringae pathovar phaseolicola and that HrcN is a peripheral protein that assembles in clusters at the membrane. A decahistidinyl HrcN derivative was overexpressed in Escherichia coli and purified to homogeneity in a folded state. Hydrodynamic analysis, cross-linking, and electron microscopy revealed four distinct HrcN forms: I, 48 kDa (monomer); II, approximately 300 kDa (putative hexamer); III, 575 kDa (dodecamer); and IV, approximately 3.5 MDa. Form III is the predominant form of HrcN at the membrane, and its ATPase activity is dramatically stimulated (>700-fold) over the basal activity of Form I. We propose that TTS ATPases catalyze protein translocation as activated homo-oligomers at the plasma membrane. 相似文献
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BACKGROUND: Primary melanoma of the lung is an extremely rare pathological entity and sparsely reported in the literature. CASE PRESENTATION: A case of primary malignant melanoma of the lung in a 41-year-old female is reported. The clinical, radiological and histopathological features are discussed. The initial symptom was cough, whereas the chest radiography showed a round opacity of the right lung. The computed tomography of the chest revealed a well-demarcated mass lesion in the right upper lobe. Endobronchial mass causing obstruction of the upper lobar bronchus was the bronchoscopic finding. Patient underwent pneumonectomy. A diagnosis of melanoma was confirmed postoperatively after the immunohistochemistry. Primary nature of the tumour in the lung results from the demonstration of characteristic junctional pattern of melanoma cells beneath the bronchial epithelium on histopathology, and from exclusion of other potential primary sites in the clinical, paraclinical and laboratory examination. CONCLUSIONS: Primary melanoma of the lung represents a rare pathological entity. Careful interpretation of histopathological information in correlation with all other findings from clinical and paraclinical studies can establish a diagnosis. Follow-up is necessary in order to diagnose potential dissemination or secondary sites of the disease. Due to the small number of cases reported in the literature, there is no experience on the management and the prognosis of the disease, but surgical resection remains the cornerstone of the treatment. 相似文献
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Polzikov M Zatsepina O Magoulas C 《Biochemical and biophysical research communications》2005,327(1):143-149
The mammalian SURF-6 protein is localized in the nucleolus, yet its function remains elusive in the recently characterized nucleolar proteome. We discovered by searching the Protein families database that a unique evolutionary conserved SURF-6 domain is present in the carboxy-terminal of a novel family of eukaryotic proteins extending from human to yeast. By using the enhanced green fluorescent protein as a fusion protein marker in mammalian cells, we show that proteins from distantly related taxonomic groups containing the SURF-6 domain are localized in the nucleolus. Deletion sequence analysis shows that multiple regions of the SURF-6 protein are capable of nucleolar targeting independently of the evolutionary conserved domain. We identified that the Saccharomyces cerevisiae member of the SURF-6 family, named rrp14 or ykl082c, has been categorized in yeast databases to interact with proteins involved in ribosomal biogenesis and cell polarity. These results classify SURF-6 as a new family of nucleolar proteins in the eukaryotic kingdom and point out that SURF-6 has a distinct domain within the known nucleolar proteome that may mediate complex protein-protein interactions for analogous processes between yeast and mammalian cells. 相似文献
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Speciation is the evolutionary process in which new barriers to gene exchange are created. These barriers may be physical, leading to spatial separation of subpopulations and resulting in allopatric speciation, or they may be temporal, giving rise to allochronic speciation, and may include the time of day or the time of year when mating takes place. Drosophila melanogaster and D. pseudoobscura show different temporal patterns of circadian locomotor activity that are determined by the circadian clock gene period (per). Genes that control aspects of behavior that might be relevant to courtship and mating, such as locomotor patterns, become obvious candidates for involvement in the speciation process. However, evidence for the role of individual genes in the mechanism of mate choice has proved elusive. We have used transgenic flies carrying the natural per genes from these two Drosophila species to reveal that per has the potential to provide the permissive conditions for speciation, by affecting mate choice through a mechanism involving the species-specific timing of mating behavior. 相似文献
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Renia Coghlan Elizabeth Gardiner Farhana Amanullah Chikwe Ihekweazu Rina Triasih Malgorzata Grzemska Charalambos Sismanidis 《PloS one》2015,10(10)
MethodologyExploratory assessments were carried out in Indonesia, Nigeria and Pakistan, reaching a range of facility types in two selected areas of each country. Record reviews and interviews of healthcare providers were carried out to assess numbers of unreported paediatric TB cases, diagnostic pathways followed and treatment regimens prescribed.
Main Findings
A total of 985 unreported diagnosed paediatric TB cases were identified over a three month period in 2013 in Indonesia from 64 facilities, 463 in Pakistan from 35 facilities and 24 in Nigeria from 20 facilities. These represent an absolute additional annualised yield to 2013 notifications reported to WHO of 15% for Indonesia, 2% for Nigeria and 7% for Pakistan. Only 12% of all facilities provided age and sex-disaggregated data. Findings highlight the challenges of confirming childhood TB. Diagnosis patterns in Nigeria highlight a very low suspicion for childhood TB. Providers note the need for paediatric medicines aligned to WHO recommendations.Conclusion: How Market Data Can Support Better Public Health Interventions
This study emphasises the impact of incomplete reporting on the estimation of disease burden and potential market size of paediatric TB medicines. Further studies on “hubs” (facilities treating large numbers of childhood TB cases) will improve our understanding of the epidemic, support introduction efforts for new treatments and better measure markets for new paediatric medicines. 相似文献17.
Charalambos Litos Despina Hatzipanayioti Alexandra Lymberopoulou-Karaliota 《Inorganica chimica acta》2007,360(7):2321-2330
The gradual release of the ligand 3,4-dihydroxybenzoic acid (3,4-DHBA) from its molybdenum complex in the presence of ascorbic acid (AscA) in a weakly acidic aqueous solution (pH ∼ 3.5) is described. We observed that the formation of the 3,4-DHBA-semiquinone oxidation state and the semidehydroascorbate is a pre-requisite for the release of the 3,4-DHBA ligand. The interaction of these radicals leads at the same time to the further degradation of AscA resulting in, among other compounds, threonic acid which participates in the reaction with molybdenum. The comparison of the complexing ability indicated that threonic acid competes with protocatechuate, while ascorbic acid is a less good ligand for the Mo(VI). Solution studies on the reaction mechanism were performed by cyclic voltammetry, NMR spectroscopy and UV-Vis spectroscopy. Isolated precipitates were investigated by NMR spectroscopy. The antioxidant properties of 3,4-DHBA and AscA were also compared using the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). 相似文献
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Kyriacou CP 《Current biology : CB》2007,17(19):R841-R843
The fruitless gene is well-known to play a key role in determining the sexual identity of the fruitfly's nervous system, but new results show that doublesex is also required in thoracic neurons to generate normal male lovesongs. 相似文献
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Bahnson A Athanassiou C Koebler D Qian L Shun T Shields D Yu H Wang H Goff J Cheng T Houck R Cowsert L 《BMC cell biology》2005,6(1):19-27