Role of the spacer boxA of Escherichia coli ribosomal RNA operons in efficient 23 S rRNA synthesis in vivo

Three out of the seven ribosomal RNA operons in Escherichia coli end in dual terminator structures. Between the two terminators of each operon is a short sequence that we report here to be an sRNA gene, transcribed as part of the ribosomal RNA primary transcript by read-through of the first terminator. The sRNA genes (rrA, rrB and rrF) from the three operons (rrnA, rrnB and rrnD) are more than 98% identical, and pull-down experiments show that their transcripts interact with Hfq and CsrA. Deletion of rrA, B, F, as well as overexpression of rrB, only modestly affect known CsrA-regulated phenotypes like biofilm formation, pgaA translation and glgC translation, and the role of the sRNAs in vivo may not yet be fully understood. Since RrA, B, F are short-lived and transcribed along with the ribosomal RNA components, their concentration reflect growth-rate regulation at the ribosomal RNA promoters and they could function to fine-tune other growth-phase-dependent processes in the cell. The primary and secondary structure of these small RNAs are conserved among species belonging to different genera of Enterobacteriales.

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In vivo incorporation of methyl groups into the ribose of Escherichia coli ribosomal RNA

Journal of Molecular Biology ◽

10.1016/0022-2836(67)90363-4 ◽

1967 ◽

Vol 30 (3) ◽

pp. 477-489 ◽

Cited By ~ 20

Author(s):

J.L. Nichols ◽

B.G. Lane

Keyword(s):

Escherichia Coli ◽

Ribosomal Rna ◽

Methyl Groups

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Role of Shiga toxin versus H7 flagellin in enterohaemorrhagic Escherichia coli signalling of human colon epithelium in vivo

Cellular Microbiology ◽

10.1111/j.1462-5822.2005.00673.x ◽

2006 ◽

Vol 8 (5) ◽

pp. 869-879 ◽

Cited By ~ 65

Author(s):

Yukiko Miyamoto ◽

Mitsutoshi Iimura ◽

James B. Kaper ◽

Alfredo G. Torres ◽

Martin F. Kagnoff

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Human Colon ◽

Enterohaemorrhagic Escherichia Coli

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The Maltodextrin System of Escherichia coli: Metabolism and Transport

Journal of Bacteriology ◽

10.1128/jb.187.24.8322-8331.2005 ◽

2005 ◽

Vol 187 (24) ◽

pp. 8322-8331 ◽

Cited By ~ 51

Author(s):

Renate Dippel ◽

Winfried Boos

Keyword(s):

Escherichia Coli ◽

Abc Transporter ◽

Binding Protein ◽

Glycogen Synthesis ◽

Equilibrium Conditions ◽

Per Se ◽

Maltodextrin Phosphorylase ◽

Internal Level

ABSTRACT The maltose/maltodextrin regulon of Escherichia coli consists of 10 genes which encode a binding protein-dependent ABC transporter and four enzymes acting on maltodextrins. All mal genes are controlled by MalT, a transcriptional activator that is exclusively activated by maltotriose. By the action of amylomaltase, we prepared uniformly labeled [14C]maltodextrins from maltose up to maltoheptaose with identical specific radioactivities with respect to their glucosyl residues, which made it possible to quantitatively follow the rate of transport for each maltodextrin. Isogenic malQ mutants lacking maltodextrin phosphorylase (MalP) or maltodextrin glucosidase (MalZ) or both were constructed. The resulting in vivo pattern of maltodextrin metabolism was determined by analyzing accumulated [14C]maltodextrins. MalP− MalZ+ strains degraded all dextrins to maltose, whereas MalP+ MalZ− strains degraded them to maltotriose. The labeled dextrins were used to measure the rate of transport in the absence of cytoplasmic metabolism. Irrespective of the length of the dextrin, the rates of transport at a submicromolar concentration were similar for the maltodextrins when the rate was calculated per glucosyl residue, suggesting a novel mode for substrate translocation. Strains lacking MalQ and maltose transacetylase were tested for their ability to accumulate maltose. At 1.8 nM external maltose, the ratio of internal to external maltose concentration under equilibrium conditions reached 106 to 1 but declined at higher external maltose concentrations. The maximal internal level of maltose at increasing external maltose concentrations was around 100 mM. A strain lacking malQ, malP, and malZ as well as glycogen synthesis and in which maltodextrins are not chemically altered could be induced by external maltose as well as by all other maltodextrins, demonstrating the role of transport per se for induction.

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In vivo oligo(A) insertions in phage MS2: role of Escherichia coli poly(A) polymerase

Nucleic Acids Research ◽

10.1093/nar/27.19.3891 ◽

1999 ◽

Vol 27 (19) ◽

pp. 3891-3898 ◽

Cited By ~ 9

Author(s):

D van Meerten

Keyword(s):

Escherichia Coli

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Fimbria-Encoding GeneyadCHas a Pleiotropic Effect on Several Biological Characteristics and Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity

Infection and Immunity ◽

10.1128/iai.01138-15 ◽

2015 ◽

Vol 84 (1) ◽

pp. 187-193 ◽

Cited By ~ 12

Author(s):

Renu Verma ◽

Thaís Cabrera Galvão Rojas ◽

Renato Pariz Maluta ◽

Janaína Luisa Leite ◽

Livia Pilatti Mendes da Silva ◽

...

Keyword(s):

Escherichia Coli ◽

Soft Agar ◽

Pleiotropic Effect ◽

Biological Characteristics ◽

Wild Type ◽

Content Type ◽

Pathogenic Escherichia Coli

The extraintestinal pathogen termed avian pathogenicEscherichia coli(APEC) is known to cause colibacillosis in chickens. The molecular basis of APEC pathogenesis is not fully elucidated yet. In this work, we deleted a component of the Yad gene cluster (yadC) in order to understand the role of Yad in the pathogenicity of the APEC strain SCI-07.In vitro, the transcription level ofyadCwas upregulated at 41°C and downregulated at 22°C. TheyadCexpressionin vivowas more pronounced in lungs than in spleen, suggesting a role in the early steps of the infection. Chicks infected with the wild-type and mutant strains presented, respectively, 80% and 50% mortality rates. The ΔyadCstrain presented a slightly decreased ability to adhere to HeLa cells with or without thed-mannose analog compared with the wild type. Real-time PCR (RT-PCR) assays showed thatfimHwas downregulated (P< 0.05) andcsgAandecpAwere slightly upregulated in the mutant strain, showing thatyadCmodulates expression of other fimbriae. Bacterial internalization studies showed that the ΔyadCstrain had a lower number of intracellular bacteria recovered from Hep-2 cells and HD11 cells than the wild-type strain (P< 0.05). Motility assays in soft agar demonstrated that the ΔyadCstrain was less motile than the wild type (P< 0.01). Curiously, flagellum-associated genes were not dramatically downregulated in the ΔyadCstrain. Taken together, the results show that the fimbrial adhesin Yad contributes to the pathogenicity and modulates different biological characteristics of the APEC strain SCI-07.

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Escherichia coli NsrR Regulates a Pathway for the Oxidation of 3-Nitrotyramine to 4-Hydroxy-3-Nitrophenylacetate

Journal of Bacteriology ◽

10.1128/jb.00508-08 ◽

2008 ◽

Vol 190 (18) ◽

pp. 6170-6177 ◽

Cited By ~ 25

Author(s):

Linda D. Rankin ◽

Diane M. Bodenmiller ◽

Jonathan D. Partridge ◽

Shirley F. Nishino ◽

Jim C. Spain ◽

...

Keyword(s):

Escherichia Coli ◽

Physiological Role ◽

Growth Conditions ◽

Growth Defect ◽

E Coli ◽

Mutant Phenotypes ◽

Culture Supernatants ◽

Chip Chip

ABSTRACT Chromatin immunoprecipitation and microarray (ChIP-chip) analysis showed that the nitric oxide (NO)-sensitive repressor NsrR from Escherichia coli binds in vivo to the promoters of the tynA and feaB genes. These genes encode the first two enzymes of a pathway that is required for the catabolism of phenylethylamine (PEA) and its hydroxylated derivatives tyramine and dopamine. Deletion of nsrR caused small increases in the activities of the tynA and feaB promoters in cultures grown on PEA. Overexpression of nsrR severely retarded growth on PEA and caused a marked repression of the tynA and feaB promoters. Both the growth defect and the promoter repression were reversed in the presence of a source of NO. These results are consistent with NsrR mediating repression of the tynA and feaB genes by binding (in an NO-sensitive fashion) to the sites identified by ChIP-chip. E. coli was shown to use 3-nitrotyramine as a nitrogen source for growth, conditions which partially induce the tynA and feaB promoters. Mutation of tynA (but not feaB) prevented growth on 3-nitrotyramine. Growth yields, mutant phenotypes, and analyses of culture supernatants suggested that 3-nitrotyramine is oxidized to 4-hydroxy-3-nitrophenylacetate, with growth occurring at the expense of the amino group of 3-nitrotyramine. Accordingly, enzyme assays showed that 3-nitrotyramine and its oxidation product (4-hydroxy-3-nitrophenylacetaldehyde) could be oxidized by the enzymes encoded by tynA and feaB, respectively. The results suggest that an additional physiological role of the PEA catabolic pathway is to metabolize nitroaromatic compounds that may accumulate in cells exposed to NO.

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