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Author (up) Ducey, T.F.; Jackson, L.; Orvis, J.; Dyer, D.W. file  url
doi  openurl
  Title Transcript analysis of nrrF, a Fur repressed sRNA of Neisseria gonorrhoeae Type Journal Article
  Year 2009 Publication Microbial Pathogenesis Abbreviated Journal Microb Pathog  
  Volume 46 Issue 3 Pages 166-170  
  Keywords Bacterial Proteins/*physiology; Base Sequence; Escherichia coli; Gene Expression Profiling; *Gene Expression Regulation, Bacterial; Models, Molecular; Molecular Sequence Data; Neisseria gonorrhoeae/*physiology; RNA, Bacterial/*genetics; RNA, Untranslated/*metabolism; Repressor Proteins/*physiology; Transcription Initiation Site  
  Abstract Like most microorganisms, Neisseria gonorrhoeae alters gene expression in response to iron availability. The ferric uptake regulator Fur has been shown to be involved in controlling this response, but the extent of this involvement remains unknown. It is known that in addition to working directly to repress gene expression, Fur may also work indirectly by controlling additional regulatory elements. Using in silico analysis, we identified a putative small RNA (sRNA) homolog of the meningococcal nrrF locus, and demonstrate that this sRNA is iron-repressible, suggesting that this is the gonococcal analog of the rhyB locus in Escherichia coli. Quantitative real-time RT-PCR analysis indicates that this transcript may also be temporally regulated. Transcript analysis identified the 5' start of the transcript, using a single reaction, fluorescent-based, primer extension assay. This protocol allows for the rapid identification of transcriptional start sites of RNA transcripts, and could be used for high-throughput transcript mapping.  
  Call Number Serial 417  
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Author (up) Shanks, R.M.Q.; Lahr, R.M.; Stella, N.A.; Arena, K.E.; Brothers, K.M.; Kwak, D.H.; Liu, X.; Kalivoda, E.J. file  url
openurl 
  Title A Serratia marcescens PigP homolog controls prodigiosin biosynthesis, swarming motility and hemolysis and is regulated by cAMP-CRP and HexS Type Journal Article
  Year 2013 Publication PloS one Abbreviated Journal PLoS One  
  Volume 8 Issue 3 Pages e57634  
  Keywords Bacterial Proteins/*genetics/metabolism; Depsipeptides/*biosynthesis/genetics/pharmacology; Erythrocytes/drug effects; *Gene Expression Regulation, Bacterial; Genetic Complementation Test; Hemolysis/drug effects; Hexosyltransferases/genetics/metabolism; Humans; Membrane Proteins/genetics/metabolism; Movement/drug effects; Mutation; Operon; Prodigiosin/*biosynthesis; Sequence Homology, Amino Acid; Serratia marcescens/*genetics/metabolism; Signal Transduction; Transcription Factors/*genetics/metabolism  
  Abstract Swarming motility and hemolysis are virulence-associated determinants for a wide array of pathogenic bacteria. The broad host-range opportunistic pathogen Serratia marcescens produces serratamolide, a small cyclic amino-lipid, that promotes swarming motility and hemolysis. Serratamolide is negatively regulated by the transcription factors HexS and CRP. Positive regulators of serratamolide production are unknown. Similar to serratamolide, the antibiotic pigment, prodigiosin, is regulated by temperature, growth phase, HexS, and CRP. Because of this co-regulation, we tested the hypothesis that a homolog of the PigP transcription factor of the atypical Serratia species ATCC 39006, which positively regulates prodigiosin biosynthesis, is also a positive regulator of serratamolide production in S. marcescens. Mutation of pigP in clinical, environmental, and laboratory strains of S. marcescens conferred pleiotropic phenotypes including the loss of swarming motility, hemolysis, and severely reduced prodigiosin and serratamolide synthesis. Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS. The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP. This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.  
  Call Number Serial 1612  
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Author (up) Zhang, Y.; Griffiths, M.W. file  url
openurl 
  Title Induced expression of the heat shock protein genes uspA and grpE during starvation at low temperatures and their influence on thermal resistance of Escherichia coli O157:H7 Type Journal Article
  Year 2003 Publication Journal of Food Protection Abbreviated Journal J Food Prot  
  Volume 66 Issue 11 Pages 2045-2050  
  Keywords Adaptation, Physiological; Bacterial Proteins/biosynthesis/*genetics; Colony Count, Microbial; Escherichia coli O157/genetics/metabolism/*physiology; *Escherichia coli Proteins; Fluorescence; Food Microbiology; *Gene Expression Regulation, Bacterial; Heat-Shock Proteins/biosynthesis/*genetics; Hot Temperature; Starvation; Time Factors  
  Abstract Heat shock proteins play an important role in protecting bacterial cells against several stresses, including starvation. In this study, the promoters for two genes encoding heat shock proteins involved in many stress responses, UspA and GrpE, were fused with the green fluorescent protein (gfp) gene. Thus, the expression of the two genes could be quantified by measuring the fluorescence emitted by the cells under different environmental conditions. The heat resistance levels of starved and nonstarved cells during storage at 5, 10, and 37 degrees C were compared with the levels of expression of the uspA and grpE genes. D52-values (times required for decimal reductions in count at 52 degrees C) increased by 11.5, 14.6, and 18.5 min when cells were starved for 3 h at 37 degrees C, for 24 h at 10 degrees C, and for 2 days at 5 degrees C, respectively. In all cases, these increases were significant (P < 0.01), indicating that the stress imposed by starvation altered the ability of E. coli O157:H7 to survive subsequent heat treatments. Thermal tolerance was correlative with the induction of UspA and GrpE. At 5 degrees C, the change in the thermal tolerance of the pathogen was positively linked to the induced expression of the grpE gene but negatively related to the expression of the uspA gene. The results obtained in this study indicate that UspA plays an important role in starvation-induced thermal tolerance at 37 degrees C but that GrpE may be more involved in regulating this response at lower temperatures. An improvement in our understanding of the molecular mechanisms involved in these cross-protection responses may make it possible to devise strategies to limit their effects.  
  Call Number Serial 312  
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