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

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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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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In vivo TNF induction by culture supernatants of antibiotic-treated Escherichia coli 07:K1. Role of antibiotic class and concentration

International Journal of Antimicrobial Agents ◽

10.1016/s0924-8579(96)00318-4 ◽

1996 ◽

Vol 7 (3) ◽

pp. 171-179

Author(s):

Willem N.M. Hustinx ◽

Barry J. Benaissa-Trouw ◽

Ingeborg van der Tweel ◽

Theo Harmsen ◽

Jan Verhoef ◽

...

Keyword(s):

Escherichia Coli ◽

Tnf Induction ◽

Culture Supernatants

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Role of OmpA and IbeB in Escherichia coli K1 Invasion of Brain Microvascular Endothelial Cells In Vitro and In Vivo

Pediatric Research ◽

10.1203/00006450-200205000-00003 ◽

2002 ◽

Vol 51 (5) ◽

pp. 559-563 ◽

Cited By ~ 60

Author(s):

Ying Wang ◽

Kwang Sik Kim

Keyword(s):

Escherichia Coli ◽

Endothelial Cells ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

Microvascular Endothelial ◽

Escherichia Coli K1

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Role of S fimbriae in Escherichia coli K1 binding to brain microvascular endothelial cells in vitro and penetration into the central nervous system in vivo

Microbial Pathogenesis ◽

10.1016/j.micpath.2004.09.002 ◽

2004 ◽

Vol 37 (6) ◽

pp. 287-293 ◽

Cited By ~ 17

Author(s):

Ying Wang ◽

Zhang Guang Wen ◽

Kwang Sik Kim

Keyword(s):

Escherichia Coli ◽

Central Nervous System ◽

Nervous System ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

The Central Nervous System ◽

Escherichia Coli K1

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Cooperative Role of Antibodies against Heat-Labile Toxin and the EtpA Adhesin in Preventing Toxin Delivery and Intestinal Colonization by Enterotoxigenic Escherichia coli

Clinical and Vaccine Immunology ◽

10.1128/cvi.00351-12 ◽

2012 ◽

Vol 19 (10) ◽

pp. 1603-1608 ◽

Cited By ~ 20

Author(s):

Koushik Roy ◽

David J. Hamilton ◽

James M. Fleckenstein

Keyword(s):

Escherichia Coli ◽

Diarrheal Disease ◽

Vaccine Development ◽

Enterotoxigenic Escherichia Coli ◽

Intestinal Colonization ◽

Content Type ◽

Heat Labile

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) is an important cause of diarrheal disease in developing countries, where it is responsible for hundreds of thousands of deaths each year. Vaccine development for ETEC has been hindered by the heterogeneity of known molecular targets and the lack of broad-based sustained protection afforded by existing vaccine strategies. In an effort to explore the potential role of novel antigens in ETEC vaccines, we examined the ability of antibodies directed against the ETEC heat-labile toxin (LT) and the recently described EtpA adhesin to prevent intestinal colonizationin vivoand toxin delivery to epithelial cellsin vitro. We demonstrate that EtpA is required for the optimal delivery of LT and that antibodies against this adhesin play at least an additive role in preventing delivery of LT to target intestinal cells when combined with antibodies against either the A or B subunits of the toxin. Moreover, vaccination with a combination of LT and EtpA significantly impaired intestinal colonization. Together, these results suggest that the incorporation of recently identified molecules such as EtpA could be used to enhance current approaches to ETEC vaccine development.

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Protective role of Mycobacterium leprae small heat-shock protein in heterologous hosts, Escherichia coli and Mycobacterium smegmatis, grown under stress

Journal of Medical Microbiology ◽

10.1099/jmm.0.057851-0 ◽

2013 ◽

Vol 62 (7) ◽

pp. 959-967 ◽

Cited By ~ 9

Author(s):

Jayapal Jeya Maheshwari ◽

Kuppamuthu Dharmalingam

Keyword(s):

Escherichia Coli ◽

Heat Shock ◽

Heat Shock Protein ◽

Mycobacterium Smegmatis ◽

Small Heat Shock Protein ◽

Mycobacterium Leprae ◽

Protective Role ◽

Low Oxygen

The aim of this study is to examine the in vivo role of a small heat-shock protein (sHsp18) from Mycobacterium leprae in the survival of heterologous recombinant hosts carrying the gene encoding this protein under different environmental conditions that are normally encountered by M. leprae during its infection of the human host. Using an Escherichia coli system where shsp18 expression is controlled by its native promoter, we show that expression of shsp18 is induced under low oxygen tension, nutrient depletion and oxidative stress, all of which reflect the natural internal environment of the granulomas where the pathogen resides for long periods. We demonstrate the in vivo chaperone activity of sHsp18 through its ability to confer survival advantage to recombinant E. coli at heat-shock temperatures. Additional evidence for the protective role of sHsp18 was obtained when Mycobacterium smegmatis harbouring a copy of shsp18 was found to multiply better in human macrophages. Furthermore, the autokinase activity of sHsp18 protein demonstrated for what is believed to be the first time in this study implies that some of the functions of sHsp18 might be controlled by the phosphorylation state of this protein. Results from this study suggest that shsp18 might be one of the factors that facilitate the survival and persistence of M. leprae under stress and autophosphorylation of sHsp18 protein could be a mechanism used by this protein to sense changes in the external environment.

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Regulatory Role of PlaR (YiaJ) for Plant Utilization in Escherichia coli K-12

Scientific Reports ◽

10.1038/s41598-019-56886-x ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Tomohiro Shimada ◽

Yui Yokoyama ◽

Takumi Anzai ◽

Kaneyoshi Yamamoto ◽

Akira Ishihama

Keyword(s):

Escherichia Coli ◽

Genetic System ◽

Regulatory Role ◽

E Coli ◽

Warm Blooded Animal ◽

Plant Utilization ◽

K 12

AbstractOutside a warm-blooded animal host, the enterobacterium Escherichia coli K-12 is also able to grow and survive in stressful nature. The major organic substance in nature is plant, but the genetic system of E. coli how to utilize plant-derived materials as nutrients is poorly understood. Here we describe the set of regulatory targets for uncharacterized IclR-family transcription factor YiaJ on the E. coli genome, using gSELEX screening system. Among a total of 18 high-affinity binding targets of YiaJ, the major regulatory target was identified to be the yiaLMNOPQRS operon for utilization of ascorbate from fruits and galacturonate from plant pectin. The targets of YiaJ also include the genes involved in the utilization for other plant-derived materials as nutrients such as fructose, sorbitol, glycerol and fructoselysine. Detailed in vitro and in vivo analyses suggest that L-ascorbate and α-D-galacturonate are the effector ligands for regulation of YiaJ function. These findings altogether indicate that YiaJ plays a major regulatory role in expression of a set of the genes for the utilization of plant-derived materials as nutrients for survival. PlaR was also suggested to play protecting roles of E. coli under stressful environments in nature, including the formation of biofilm. We then propose renaming YiaJ to PlaR (regulator of plant utilization).

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