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排序方式: 共有423条查询结果,搜索用时 140 毫秒
321.
Petros Papadopoulos Laura Gutiérrez Jeroen Demmers Elisabeth Scheer Farzin Pourfarzad Dimitris N. Papageorgiou Elena Karkoulia John Strouboulis Harmen J. G. van de Werken Reinier van der Linden Peter Vandenberghe Dick H. W. Dekkers Sjaak Philipsen Frank Grosveld Làszlò Tora 《Molecular and cellular biology》2015,35(12):2103-2118
322.
Three‐dimensional electron microscopy reconstruction and cysteine‐mediated crosslinking provide a model of the type III secretion system needle tip complex
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Martin Cheung Da‐Kang Shen Fumiaki Makino Takayuki Kato A. Dorothea Roehrich Isabel Martinez‐Argudo Matthew L. Walker Isabel Murillo Xia Liu Maria Pain James Brown Gordon Frazer Judith Mantell Petros Mina Thomas Todd Richard B. Sessions Ariel J. Blocker 《Molecular microbiology》2015,95(1):31-50
Type III secretion systems are found in many Gram‐negative bacteria. They are activated by contact with eukaryotic cells and inject virulence proteins inside them. Host cell detection requires a protein complex located at the tip of the device's external injection needle. The Shigella tip complex (TC) is composed of IpaD, a hydrophilic protein, and IpaB, a hydrophobic protein, which later forms part of the injection pore in the host membrane. Here we used labelling and crosslinking methods to show that TCs from a ΔipaB strain contain five IpaD subunits while the TCs from wild‐type can also contain one IpaB and four IpaD subunits. Electron microscopy followed by single particle and helical image analysis was used to reconstruct three‐dimensional images of TCs at ~20 Å resolution. Docking of an IpaD crystal structure, constrained by the crosslinks observed, reveals that TC organisation is different from that of all previously proposed models. Our findings suggest new mechanisms for TC assembly and function. The TC is the only site within these secretion systems targeted by disease‐protecting antibodies. By suggesting how these act, our work will allow improvement of prophylactic and therapeutic strategies. 相似文献
323.
Dimopoulou I Armaganidis A Douka E Mavrou I Augustatou C Kopterides P Lyberopoulos P Tzanela M Orfanos SE Pelekanou E Kostopanagiotou G Macheras A Giamarellos-Bourboulis EJ 《Cytokine》2007,37(1):55-61
BACKGROUND: The course of serum cytokine levels in patients with postoperative systemic inflammatory response syndrome (SIRS) after major abdominal surgery remains currently unclear. METHODS: Blood was sampled pre- and post-operatively and on days 1 and 2 in 40 patients undergoing major abdominal surgery. Concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin (IL) -6, IL-8, and IL-10 were measured by the LINCOplex assay; those of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) by an enzyme immunoassay. RESULTS: Compared to their pre-operative values, sTREM-1 was elevated on day 2; TNFalpha on day 1; IL-6 and IL-10 post-operatively and on days 1 and 2; and IL-8 post-operatively and on day 1. The duration of operation correlated with TNFalpha and IL-10 at all sampling times, and with IL-6 post-operatively. There were no differences in cytokine concentrations between patients who exhibited post-operative complications and those who did not. IL-10/TNFalpha below 30 was found in all patients with complications (100%) and in 20 patients without complications (64.5%, p: 0.043). CONCLUSIONS: SIRS following major surgery is characterised by complex alterations in cytokine concentrations. The balance between TNFalpha and IL-10 seems to determine the occurrence of post-operative complications. 相似文献
324.
Sharon Mumby Rajiv Chaturvedi Joseph Brierley Christopher Lincoln Andy Petros Andrew Redington John M. C. Gutteridge 《Free radical research》1999,31(2):141-148
Cardiopulmonary bypass surgery is associated with the release of low molecular mass iron, which increases the saturation of plasma transferrin to over 50% in all adult patients treated. In a significant minority, however plasma transferrin becomes 100% iron saturated and non-transferrin bound iron can be detected in the plasma. An iron-saturated transferrin is also a common physiological finding in normal term and pre-term infants at a time when their plasma antioxidants, which protect against iron toxicity and radical scavening, are profoundly different from those seen in adults. This study was conducted to assess the extent to which antioxidants, which protect against iron toxicity, are altered in neonates, infants, and children undergoing cardiopulmonary bypass surgery. 相似文献
325.
Applicability of an Arrhenius Model for the Combined Effect of Temperature and CO2 Packaging on the Spoilage Microflora of Fish 总被引:1,自引:0,他引:1
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Konstantinos P. Koutsoumanis Petros S. Taoukis Eleftherios H. Drosinos George-John E. Nychas 《Applied microbiology》2000,66(8):3528-3534
The temperature behavior of the natural microflora on the Mediterranean fish red mullet (Mullus barbatus) was examined as a case study. The growth of the spoilage bacteria Pseudomonas spp., Shewanella putrefaciens, Brochothrix thermosphacta, and lactic acid bacteria was modeled as a function of temperature and the concentration of carbon dioxide in modified atmosphere packaging. Combined models were developed and comparatively assessed based on polynomial, Belehradek, and Arrhenius equations. The activation energy parameter of the Arrhenius model, EA, was independent of the packaging atmosphere and ranged from 75 to 85 kJ/mol for the different bacteria, whereas the preexponential constant decreased exponentially with the packaging CO2 concentration. We evaluated the applicability of the models developed by using experimental bacterial growth rates obtained from 42 independent experiments performed with three Mediterranean fish species and growth rates predicted from the models under the same temperature and packaging conditions. The accuracy factor and bias factor were used as statistical tools for evaluation, and the developed Arrhenius model and the Belehradek model were judged satisfactory overall. 相似文献
326.
Yin-Goen Q Dale J Yang WL Phan J Moffitt R Petros JA Datta MW Amin MB Wang MD Young AN 《Histology and histopathology》2006,21(3):325-339
Kidney neoplasms are classified by light microscopy using the World Health Organization (WHO) system. The WHO system defines histopathologic tumor subtypes with distinct clinical behavior and underlying genetic mutations. In adults, the common malignant subtypes are variants of renal cell carcinoma (RCC). Histopathologic classification is critical for clinical management of RCC, but is becoming more complex with recognition of novel tumor subtypes, development of procedures yielding small diagnostic biopsies, and emergence of molecular therapies directed at tumor gene activity. Therefore, classification systems based on gene expression are likely to become essential for diagnosis, prognosis and treatment of kidney tumors. Recent DNA microarray studies have shown that clinically relevant renal tumor subtypes are characterized by distinct gene expression profiles, which are useful for discovery of novel diagnostic and prognostic biomarkers. In this review, we summarize the WHO classification system for renal tumors, general applications of microarray technology in cancer research, and specific microarray studies that have advanced knowledge of renal tumor diagnosis, prognosis, therapy and pathobiology. 相似文献
327.
328.
Phil J. Cox Paraskevas Aslanidis Petros Karagiannidis Sotiris Hadjikakou 《Inorganica chimica acta》2000,310(2):268-272
Mixed-ligand complexes of the formula [Ag(PPh3)(L)Br]2 were obtained by treatment of various heterocyclic thiones L {L=pyridine-2-thione (py2SH), pyrimidine-2-thione (pymtH), benz-1,3-imidazoline-2-thione (bzimtH2), benz-1,3-thiazoline-2-thione (bztztH), 1-methyl-1,3-imidazoline-2-thione (meimtH) and 5-methoxy-benz-1,3-imidazoline-2-thione (5MeObzimtH2)} with equivalent quantities of silver(I) bromide and triphenylphosphine in dry acetone. The compounds were characterized by their IR, far-IR, UV–Vis and 1H NMR spectroscopic data. The crystal structure of [Ag(PPh3)(pymtH)Br]2 was determined by single-crystal X-ray diffraction methods. The complex exhibits a planar Ag2Br2 moiety in which each of the doubly bromine-bridged Ag(I) centres is further bonded to one phosphine P and one thione S atom. 相似文献
329.
Cutting the Gordian Knot: Phylogenetic and ecological diversification of the Mesalina brevirostris species complex (Squamata,Lacertidae)
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Jiří Šmíd Jiří Moravec Václav Gvoždík Jan Štundl Daniel Frynta Petros Lymberakis Paschalia Kapli Thomas Wilms Andreas Schmitz Mohammed Shobrak Saeed Hosseinian Yousefkhani Eskandar Rastegar‐Pouyani Aurora M. Castilla Johannes Els Werner Mayer 《Zoologica scripta》2017,46(6):649-664
Mesalina are small lacertid lizards occurring in the Saharo‐Sindian deserts from North Africa to the east of the Iranian plateau. Earlier phylogenetic studies indicated that there are several species complexes within the genus and that thorough taxonomic revisions are needed. In this study, we aim at resolving the phylogeny and taxonomy of the M. brevirostris species complex distributed from the Middle East to the Arabian/Persian Gulf region and Pakistan. We sequenced three mitochondrial and three nuclear gene fragments, and in combination with species delimitation and species‐tree estimation, we infer a time‐calibrated phylogeny of the complex. The results of the genetic analyses support the presence of four clearly delimited species in the complex that diverged approximately between the middle Pliocene and the Pliocene/Pleistocene boundary. Species distribution models of the four species show that the areas of suitable habitat are geographically well delineated and nearly allopatric, and that most of the species have rather divergent environmental niches. Morphological characters also confirm the differences between the species, although sometimes minute. As a result of all these lines of evidence, we revise the taxonomy of the Mesalina brevirostris species complex. We designate a lectotype for Mesalina brevirostris Blanford, 1874; resurrect the available name Eremias bernoullii Schenkel, 1901 from the synonymy of M. brevirostris; elevate M. brevirostris microlepis (Angel, 1936) to species status; and describe Mesalina saudiarabica, a new species from Saudi Arabia. 相似文献
330.
Li Zheng Lauren Ehardt Blake McAlpin Imad About Doohak Kim Silvana Papagerakis Petros Papagerakis 《Experimental cell research》2014
Although a big deal of dental research is being focused to the understanding of early stages of tooth development, a huge gap exist on our knowledge on how the dental hard tissues are formed and how this process is controlled daily in order to produce very complex and diverse tooth shapes adapted for specific functions. Emerging evidence suggests that clock genes, a family of genes that controls circadian functions within our bodies, regulate also dental mineralized tissues formation. Enamel formation, for example, is subjected to rhythmical molecular signals that occur on short (24 h) periods and control the secretion and maturation of the enamel matrix. Accordingly, gene expression and ameloblast functions are also tightly modulated in regular daily intervals. This review summarizes the current knowledge on the circadian controls of dental mineralized tissues development with a special emphasis on amelogenesis. 相似文献