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  • 1
    Electronic Resource
    Electronic Resource
    A novel regulatory system required for pathogenicity of Xanthomonas campestris is mediated by a small diffusible signal molecule (1997)
    Oxford BSL : Blackwell Publishing Ltd
    Molecular microbiology 24 (1997), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Mutations in the seven clustered rpf genes cause downregulated synthesis of extracellular enzymes and reduced virulence of Xanthomonas campestris pathovar campestris (Xcc). The phenotype of mutants in one of the genes, rpfF, can be restored by a diffusible extracellular factor (DSF) produced by all Xcc strains tested, apart from rpfF and rpfB mutants. DSF accumulates in early stationary phase (when synthesis of enzymes is maximal), but levels decline subsequently. Addition of DSF to exponentially-growing wild-type bacteria does not cause precocious enzyme synthesis. rpfB and rpfF are expressed throughout growth, but the rate increases in early stationary phase. RpfB is predicted to be a long-chain fatty acyl CoA ligase, and RpfF shows some relatedness to enoyl CoA hydratases. The properties of DSF suggest that it may be a fatty-acid derivative, and certain lipid preparations possess DSF activity at higher concentrations. These include lipid extracts and acid-hydrolysed lipopolysaccharide and lipid A from Xcc, and purified dodecanoic and hydroxydodecanoic acid. DSF production is confined to certain xanthomonads. We propose a model for the DSF system, which represents a novel mechanism for regulating virulence factor synthesis in response to physiological or environmental changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1997.3721736.x
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  • 2
    Electronic Resource
    Electronic Resource
    The rpfA gene of Xanthomonas campestris pathovar campestris, which is involved in the regulation of pathogenicity factor production, encodes an aconitase (1998)
    Oxford BSL : Blackwell Publishing Ltd
    Molecular microbiology 28 (1998), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Xanthomonas campestris pv campestris (Xcc) is a plant pathogenic bacterium that controls the production of pathogenicity factors in part by a cluster of genes designated rpf (regulation of pathogenicity factors). Sequence analysis of one of these genes (rpfA) revealed an open reading frame with amino acid sequence similarity to aconitases from other bacteria. Aconitase activity was lower in cellular extracts of an rpfA::Tn5 mutant than in those from the wild type. A zymogram of aconitase activity after native gel electrophoresis showed the presence of two distinct aconitases in Xcc; the major aconitase was absent in the rpfA::Tn5 mutant. This mutant also had reduced levels of extracellular enzymes and extracellular polysaccharide (EPS). Supplying rpfA in trans to the rpfA::Tn5 mutant restored both the major aconitase activity and the synthesis of these pathogenicity factors. The transcription of the genes for two extracellular enzymes (prtA, encoding a serine protease, and engXCA, encoding endoglucanase) was reduced in the rpfA mutant background. Because some eukaryotic aconitases are also involved in iron regulation, we explored a possible connection between rpfA and iron metabolism. Intracellular iron levels in the mutants were lower than in the wild type as assessed by sensitivity to the iron-activated antibiotic, streptonigrin. Wild-type bacteria grown in iron-deficient conditions had a similar sensitivity to streptonigrin as the aconitase mutant. Overall, these results suggest that a prokaryotic aconitase can also act as a regulator of gene expression and that the regulation is possibly related to changes in intracellular iron levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1998.00852.x
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  • 3
    Electronic Resource
    Electronic Resource
    Siraita grosvenorii (Luo Han Guo; Cucurbitaceae) is a new host of Ralstonia solanacearum in China (2005)
    Oxford, UK : Blackwell Science Ltd
    Plant pathology 54 (2005), S. 0 
    Details
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3059.2005.01227.x
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  • 4
    Electronic Resource
    Electronic Resource
    The efficacy of thymosin in the treatment of chronic hepatitis B virus infection: a meta-analysis (2001)
    Oxford UK : Blackwell Science Ltd
    Alimentary pharmacology & therapeutics 15 (2001), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Trials of thymosin treatment in chronic hepatitis B virus infection have been small and the results have been inconsistent.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To conduct a meta-analysis to evaluate the efficacy of thymosin treatment in chronic hepatitis B virus infection.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Randomized controlled trials comparing thymosin for over 24 weeks vs. placebo (or usual care) in the treatment of chronic hepatitis B virus infection were identified through MEDLINE, EMBASE and the Cochrane Register of Clinical Trials. Biochemical (normalization of transaminases) and virological (loss of hepatitis B virus DNA and hepatitis B e antigen) responses were analysed using the intention-to-treat method. The odds ratio was used to measure the magnitude of the efficacy.〈section xml:id="abs1-4"〉〈title type="main"〉Results:Five trials (353 patients) were identified. The odds ratio (95% confidence interval) of the virological response of thymosin over placebo at the end of treatment, 6 months post-treatment and 12 months post-treatment were 0.56 (0.2–1.52), 1.67 (0.83–3.37) and 2.67 (1.25–5.68), respectively. There was an increasing trend of the virological response with time since the cessation of thymosin treatment (P=0.02). There was no difference in the biochemical response between the thymosin and placebo groups at the end of treatment, 6 months post-treatment and 12 months post-treatment.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:Thymosin is effective in suppressing viral replication in chronic hepatitis B virus infection, but the effect is delayed until 12 months after the cessation of treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.2001.01135.x
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  • 5
    Electronic Resource
    Electronic Resource
    Detection of dural involvement by magnetic resonance imaging in adult patients with acute leukemias — preliminary experience (1995)
    Springer
    Annals of hematology 70 (1995), S. 243-249 
    Details
    ISSN: 1432-0584
    Keywords: Acute leukemia ; Dura ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Retrospectively, the dura in 18 adult patients with acute leukemia were evaluated by gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). Abnormal dural enhancements were detected in three of four patients with positive cerebrospinal fluid (CSF) cytology, in one of five with suspicious central nervous system (CNS) disease, and in two of nine asymptomatic patients. Computed tomography failed to demonstrate any dural abnormality in these six patients. The abnormal dural enhancement was found in either (a) the brain and the spine, (b) the thoracolumbar spine, or (c) the area adjacent to the parenchymal lesions. Three of the patients were in hematological remission stage; disappearance of the abnormal dural enhancement was observed 1–2 months after radiotherapy and high-dose systemic chemotherapy. The results suggest that MRI is a sensitive and noninvasive imaging modality and superior to CT in detecting dural disease in leukemic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784043
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  • 6
    Electronic Resource
    Electronic Resource
    Detection of dural involvement by magnetic resonance imaging in adult patients with acute leukemias – preliminary experience (1995)
    Springer
    Annals of hematology 70 (1995), S. 243-249 
    Details
    ISSN: 1432-0584
    Keywords: Key words Acute leukemia ; Dura ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Retrospectively, the dura in 18 adult patients with acute leukemia were evaluated by gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI). Abnormal dural enhancements were detected in three of four patients with positive cerebrospinal fluid (CSF) cytology, in one of five with suspicious central nervous system (CNS) disease, and in two of nine asymptomatic patients. Computed tomography failed to demonstrate any dural abnormality in these six patients. The abnormal dural enhancement was found in either (a) the brain and the spine, (b) the thoracolumbar spine, or (c) the area adjacent to the parenchymal lesions. Three of the patients were in hematological remission stage; disappearance of the abnormal dural enhancement was observed 1–2 months after radiotherapy and high-dose systemic chemotherapy. The results suggest that MRI is a sensitive and noninvasive imaging modality and superior to CT in detecting dural disease in leukemic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784043
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  • 7
    Electronic Resource
    Electronic Resource
    Subtyping of human T-lymphotropic virus type I by amplification of long terminal repeat sequences and restriction fragment length polymorphism analysis in carriers with multiple transfusions (1996)
    Springer
    Annals of hematology 73 (1996), S. 127-134 
    Details
    ISSN: 1432-0584
    Keywords: Key words Human T-lymphotropic virus type I ; Long terminal repeat ; Restriction fragment length polymorphism ; Polymerase chain reaction ; Transfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Five major subtypes of human T-lymphotropic virus type I (HTLV-I) have been proposed: cosmopolitan, Japanese, West African, Central African, and Melanesian. Based on nucleotide variations specific to particular subtypes, it was possible to genotype HTLV-I rapidly by restriction fragment length polymorphism (RFLP) studies following polymerase chain reaction (PCR) . In this study, the restriction patterns of two LTR fragments were analyzed using eight restriction endonucleases (AvaI, Eco57I, BsoFI, NdeI, SacI, DraI, MaeII, and MaeIII). Genotyping of HTLV-I was done in nine patients with adult T-cell leukemia or HTLV-I-associated myelopathy/tropical spastic paraparesis, in three prostitutes, and in 19 carriers with multiple transfusion in Taiwan. The subtyping results of RFLP studies using these eight restriction endonucleases were in accordance with those of phylogenetic analysis. A substitution of G by A at nucleotide position 503, which creates the DraI site but suppresses the SacI site, was found not only in the Japanese subtype but also in a minority of the cosmopolitan subtype. A mutation near the position of subtype-specific nucleotide variations might suppress the restriction site and lead to unexpected restriction patterns. Amplification of more than one proviral fragment and RFLP studies with a group of appropriate restriction endonucleases may provide rapid and accurate genotyping of HTLV-I. More carriers are required to evaluate the possibility of mixed infection with different HTLV-I subtypes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002770050213
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  • 8
    Electronic Resource
    Electronic Resource
    Envelope gene sequences of human T-lymphotropic virus type I in Taiwan (1996)
    Springer
    Archives of virology 141 (1996), S. 219-229 
    Details
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three major types of HTLV-I had been proposed, the Melanesian type, the Zairian type, and the cosmopolitan type, which was further divided into subtypes A, B and C, according to the phylogenetic tree constructed from LTR sequences of current HLTV-I isolates. In this study, the envelope gene sequences of HTLV-I from 9 Taiwanese were analyzed. Based on the phylogenetic tree constructed by unweighed pair group method and the sequence homology analysis by GCG computer programs, the envelope gene sequences of HTLV-I proviruses from these 9 Taiwanese belonged to subtype A or subtype B of the cosmopolitan type and were closely related to HTLV-I from Japan. Twelve subtype-specific nucleotide variations were deduced from the comparison of complete or partial envelope gene sequences of 16 HTLV-I isolates of known subtypes as well as those of 9 Taiwanese. These data provided the basis for subtyping the cosmopolitan type of HTLV-I by amplification of envelope gene sequences and restriction fragment length polymorphism studies. A more extensive survey based upon this proposal was warranted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01718395
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  • 9
    Electronic Resource
    Electronic Resource
    Molecular cloning of protease gene(s) from Xanthomanas campestris pv. campestris: Expression in Escherichia coli and role in pathogenicity (1987)
    Springer
    Molecular genetics and genomics 210 (1987), S. 443-448 
    Details
    ISSN: 1617-4623
    Keywords: Cloning ; Xanthomonas ; Protease ; Pathogenicity ; Brassica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The recombinant plasmid pIJ3070 isolated from a genomic library of Xanthomonas campestris pv. campestris constructed in the conjugal cosmid pLAFR3 contains protease gene(s) which can be expressed in Escherichia coli. Tn5 mutagenesis and subcloning revealed that the protease structural gene(s) is(are) located in a ca. 10 kb EcoRI fragment. Several protease-minus mutants of X. c. campestris were obtained by Tn5 mutagenesis of pIJ3070 and marker exchange techniques. Studies of pathogenicity of these Tn5 mutants showed that the protease is not critically important for the pathogenicity of X. c. campestris on turnip plants but may play a minor role in disease development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327195
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  • 10
    Electronic Resource
    Electronic Resource
    Some new observations on yield surfaces (1974)
    Springer
    Acta mechanica 20 (1974), S. 23-39 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung In dieser Arbeit werden Resultate von Experimenten, in denen zwei dünnwandige Rohre aus handelsreinem, normal-geglühtem Aluminium durch Zug und Torsion bei erhöhten Temperaturen, im plastischen Bereich belastet wurden, angegeben. Im ersten Versuch wurde durch Torsion zyklisch vorverformt und im zweiten durch Zug bei Umkehr des Belastungsweges. Es wird gezeigt, daß das in [3] angegebene Verfestigungsgesetz bei Vorverformung gegen den Ursprung des Spanungsraumes eine Aufweitung der Fließkurve in der Vorverformungsrichtung bedingt. Es wird ferner gezeigt, daß die Existenz von Vorverformungen, die keine Veränderung der Fließflächen bewirken, postuliert werden kann. In dieser Arbeit wird außerdem die Existenz negativer plastischer Verzerrungen gezeigt, und, daß der Beginn der Fließflächen eng verknüpft ist mit den Einhüllenden der Proportionalitätsgrenzen-Flächen.
    Notes: Summary This paper presents the results of experiments in which two thinwalled tubes of commercially pure aluminium in the annealed condition were loaded in combined tension and torsion in the plastic region at elevated temperatures. In the first test prestressing was in torsion but of a cyclic nature. In the other test prestressing included a path reversal in tension. It is shown that the hardening law introduced previously [3] is such that prestressing towards the origin of the stress space produces an increase in the width of the yield curve in the prestressing direction. It is also shown that a locus of zero deformation of yield surfaces can be postulated. In the present paper we also show the existence of negative plastic strains and we show that offset yield surfaces are closely related to envelopes of proportional limit yield surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01374960
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