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  • 1
    Language: English
    In: Nucleic acids research, March 2012, Vol.40(5), pp.2020-31
    Description: The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promoter element and no consensus Shine-Dalgarno sequence. Moreover, 14% of all mRNAs are leaderless and 13% of them have unusually long 5'-UTRs. Northern blot analyses confirmed 16 intergenic small RNAs and seven cis-encoded antisense RNAs in Xcv. Expression of eight intergenic transcripts was controlled by HrpG and HrpX, key regulators of the Xcv type III secretion system. More detailed characterization identified sX12 as a small RNA that controls virulence of Xcv by affecting the interaction of the pathogen and its host plants. The transcriptional landscape of Xcv is unexpectedly complex, featuring abundant antisense transcripts, alternative TSSs and clade-specific small RNAs.
    Keywords: RNA, Small Untranslated -- Metabolism ; Virulence Factors -- Genetics ; Xanthomonas Campestris -- Genetics
    ISSN: 03051048
    E-ISSN: 1362-4962
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  • 2
    Language: English
    In: 2013, Vol.9(9), p.e1003626
    Description: Small noncoding RNAs (sRNAs) are ubiquitous posttranscriptional regulators of gene expression. Using the model plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria ( Xcv ), we investigated the highly expressed and conserved sRNA sX13 in detail. Deletion of sX13 impinged on Xcv virulence and the expression of genes encoding components and substrates of the Hrp type III secretion (T3S) system. qRT-PCR analyses revealed that sX13 promotes mRNA accumulation of HrpX, a key regulator of the T3S system, whereas the mRNA level of the master regulator HrpG was unaffected. Complementation studies suggest that sX13 acts upstream of HrpG. Microarray analyses identified 63 sX13-regulated genes, which are involved in signal transduction, motility, transcriptional and posttranscriptional regulation and virulence. Structure analyses of in vitro transcribed sX13 revealed a structure with three stable stems and three apical C-rich loops. A computational search for putative regulatory motifs revealed that sX13-repressed mRNAs predominantly harbor G-rich motifs in proximity of translation start sites. Mutation of sX13 loops differentially affected Xcv virulence and the mRNA abundance of putative targets. Using a GFP-based reporter system, we demonstrated that sX13-mediated repression of protein synthesis requires both the C-rich motifs in sX13 and G-rich motifs in potential target mRNAs. Although the RNA-binding protein Hfq was dispensable for sX13 activity, the hfq mRNA and Hfq::GFP abundance were negatively regulated by sX13. In addition, we found that G-rich motifs in sX13-repressed mRNAs can serve as translational enhancers and are located at the ribosome-binding site in 5% of all protein-coding Xcv genes. Our study revealed that sX13 represents a novel class of virulence regulators and provides insights into sRNA-mediated modulation of adaptive processes in the plant pathogen Xanthomonas . ; Since the discovery of the first regulatory RNA in 1981, hundreds of small RNAs (sRNAs) have been identified in bacteria. Although sRNA-mediated control of virulence was demonstrated for numerous animal- and human-pathogenic bacteria, sRNAs and their functions in plant-pathogenic bacteria have been enigmatic. We discovered that the sRNA sX13 is a novel virulence regulator of pv. (), which causes bacterial spot disease on pepper and tomato. sX13 contributes to the -plant interaction by promoting the synthesis of an essential pathogenicity factor of , i. e., the type III secretion system. Thus, in addition to transcriptional regulation, sRNA-mediated posttranscriptional regulation contributes to virulence of plant-pathogenic xanthomonads. To repress target mRNAs carrying G-rich motifs, sX13 employs C-rich loops. Hence, sX13 exhibits striking structural similarity to sRNAs in distantly related human pathogens, e. g., and , suggesting that structure-driven target regulation via C-rich motifs represents a conserved feature of sRNA-mediated posttranscriptional regulation. Furthermore, sX13 is the first sRNA shown to control the mRNA level of , which encodes a conserved RNA-binding protein required for sRNA activity and virulence in many enteric bacteria.
    Keywords: Research Article ; Biology
    ISSN: 1553-7366
    E-ISSN: 1553-7374
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  • 3
    Language: English
    In: RNA Biology, 01 March 2010, Vol.7(2), pp.120-124
    Description: The genome of Xanthomonas campestris pv. vesicatoria encodes a constitutively expressed small RNA, which we designate PtaRNA1, "Plasmid transferred anti-sense RNA". It exhibits all hallmarks of a novel RNA antitoxin that proliferates by frequent horizontal transfer. It shows an erratic phylogenetic...
    Keywords: Anatomy & Physiology
    ISSN: 1547-6286
    E-ISSN: 1555-8584
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  • 4
    In: Molecular Plant Pathology, November 2018, Vol.19(11), pp.2473-2487
    Description: The type III secretion (T3S) system, an essential pathogenicity factor in most Gram‐negative plant‐pathogenic bacteria, injects bacterial effector proteins directly into the plant cell cytosol. Here, the type III effectors (T3Es) manipulate host cell processes to suppress defence and establish appropriate conditions for bacterial multiplication in the intercellular spaces of the plant tissue. T3E export depends on a secretion signal which is also present in ‘non‐effectors’. The latter are secreted extracellular components of the T3S apparatus, but are not translocated into the plant cell. How the T3S system discriminates between T3Es and non‐effectors is still enigmatic. Previously, we have identified a putative translocation motif (TrM) in several T3Es from pv. (). Here, we analysed the TrM of the effector XopB in detail. Mutation studies showed that the proline/arginine‐rich motif is required for efficient type III‐dependent secretion and translocation of XopB and determines the dependence of XopB transport on the general T3S chaperone HpaB. Similar results were obtained for other effectors from . As the arginine residues of the TrM mediate specific binding of XopB to cardiolipin, one of the major lipid components in membranes, we assume that the association of T3Es to the bacterial membrane prior to secretion supports type III‐dependent export.
    Keywords: Avrbs1 ; Avrbst ; Cardiolipin ; Liposomes ; Type Iii Secretion
    ISSN: 1464-6722
    E-ISSN: 1364-3703
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  • 5
    In: Suicide and Life‐Threatening Behavior, August 2007, Vol.37(4), pp.367-378
    Description: The associations between life events in the 12 months preceding an episode of self‐poisoning resulting in hospital attendance (the index episode), and the suicide intent of this episode were compared in individuals for whom the index episode was their first, episode and in individuals in whom it was a recurrence of DSH. Results indicated a significant interaction between life events, repetition status, and gender in the prediction of suicide intent, the association between life events and intent being moderated by repetition status in women only. The results provide preliminary evidence to suggest the presence of a suicidal process in women, in which the impact of negative life events on suicide intent diminishes across episodes.
    Keywords: Suicide ; Life History ; Females ; Sociology of Health and Medicine; Substance Use/Abuse & Compulsive Behaviors (Drug Abuse, Addiction, Alcoholism, Gambling, Eating Disorders, Etc.) ; Article;
    ISSN: 0363-0234
    E-ISSN: 1943-278X
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  • 6
    Language: English
    In: RNA Biology, 01 May 2014, Vol.11(5), pp.457-463
    Description: The genus Xanthomonas comprises a large group of plant-pathogenic bacteria. The infection and bacterial multiplication in the plant tissue depends on the type III secretion system and other virulence determinants. Recent studies revealed that bacterial virulence is also controlled at the post-transcriptional...
    Keywords: Transcriptome ; Xanthomonas ; Plant Pathogens ; Srnas ; RNA-Binding Proteins ; Post-Transcriptional Regulation ; Bacteria ; Anatomy & Physiology
    ISSN: 1547-6286
    E-ISSN: 1555-8584
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  • 7
    Language: English
    In: The Journal of heart valve disease, March 2004, Vol.13(2), pp.174-80; discussion 180-1
    Description: The Ross operation as aortic valve replacement has undergone technical evolution. Originally described as a subcoronary implant, the full-root replacement technique is now more common worldwide. It remains unclear which of the two techniques has the better results. Hence, the hemodynamic performances of the two implantation methods, as applied by two experienced centers, were compared as part of the German Ross Registry. In total, 132 (Group 1, root replacement, mean age 40 +/- 14 years) and 249 (Group 2, subcoronary implant, mean age 48 +/- 14 years) consecutively operated patients were compared clinically and echocardiographically. Data were analyzed focusing on pulmonary autograft and homograft function at mid-term (2.78 +/- 1.89 versus 2.26 +/- 2.11 years). Echocardiography revealed autograft peak systolic gradients of 5.0 +/- 2.7 mmHg for Group 1 and 6.7 +/- 3.7 mmHg for Group 2 (p I was present in 1.5% (2/132) of Group 1 and 2.8% (7/249) of Group 2 patients. Pulmonary insufficiency grade 〉 I was 17.4% (23/132) for Group 1 and 4.8% (12/249) for Group 2 (p 〈 0.05). Although both groups enjoyed excellent hemodynamics in the mid-term, the root replacement technique had the advantage of larger annulus diameters and greater aortic EOA. Clinically relevant autograft regurgitation in both groups was gratifyingly rare, and seemed to be independent of surgical technique. Long-term durability of the more demanding subcoronary technique versus the problems of larger dimensions of the sinus of Valsalva and sinotubular junction in the free-root technique, remains to be proven. Apparent differences in pulmonary homograft hemodynamics can most likely be explained by surgical differences, younger patients in Group 1, and by homograft variation.
    Keywords: Heart Valve Prosthesis Implantation ; Hemodynamics -- Physiology
    ISSN: 0966-8519
    Source: MEDLINE/PubMed (U.S. National Library of Medicine)
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  • 8
    Description: Das Gram-negative pflanzenpathogene γ-Proteobakterium Xanthomonas campestris pv. vesicatoria (Xcv) ist der Erreger der bakteriellen Fleckenkrankheit auf Paprika und Tomate. Mittels eines cDNA-Sequenzieransatzes wurden 1.421 potentielle Transskriptionsstartpositionen sowie 24 neuartige und potentiell regulatorische RNAs im Xcv-Stamm 85-10 identifiziert. Durch genetische Analysen wurde nachgewiesen, dass die nicht-kodierenden RNAs sX12 und sX13 die Virulenz von Xcv fördern. Zudem wurde gezeigt, dass sX13 die Expression von Virulenzgenen reguliert und vermutlich zur bakteriellen Anpassung an Umweltbedingungen beiträgt. sX13 weist drei ‚Stem-Loop‘ Strukturen mit ‚C‘-reichen Loops auf, welche in unterschiedlichem Maße zur Virulenz von Xcv beitragen. Mittels eines GFP-Reportersystems wurde nachgewiesen, dass ‚C‘-reiche sX13 Loops und ‚G‘-reiche Motive in potentiellen Ziel-mRNAs für die sX13-abhängige Repression der Proteinsynthese essentiell sind.... ; The Gram-negative plant-pathogenic γ-proteobacterium Xanthomonas campestris pv. vesicatoria (Xcv) is the causal agent of bacterial spot disease on pepper and tomato. Using a cDNA-sequencing approach 1,421 putative transcription start sites and 24 putative regulatory RNAs were identified in Xcv strain 85-10. Genetic analyses showed that the noncoding RNAs sX12 and sX13 promote virulence of Xcv. Furthermore the data suggests that sX13 regulates the expression of virulence genes and contributes to environmental adaptation of Xcv. sX13 consists of three stem-loops with ‘C’-rich loops, which differentially contribute to virulence of Xcv. Using a GFP-reporter system, both the ‘C’-rich sX13 loops and ‘G’-rich motifs in presumed target mRNAs were shown to be essential for the sX13-dependent repression of protein synthesis....
    Keywords: Xanthomonas ; Small Rna ; Non-Coding Rna ; Online-Publikation ; Hochschulschrift ; Xanthomonas; Pflanzenpathogen; Virulenz; Rna-Seq; Small Rnas; Srnas; Nicht-Kodierende Rnas; Transkriptom ; Xanthomonas; Plant Pathogen; Virulence; Rna-Seq; Small Rnas; Srnas; Noncoding Rnas; Transcriptome ; Ddc::500 Naturwissenschaften Und Mathematik::570 Biowissenschaften; Biologie::571 Physiologie Und Verwandte Themen
    Source: DataCite
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