Biofilm Growth of Escherichia coli Is Subject to cAMP-Dependent and cAMP-Independent Inhibition

2015 ◽  
Vol 25 (2-3) ◽  
pp. 209-225 ◽  
Author(s):  
Sarah L. Sutrina ◽  
Kia Daniel ◽  
Michael Lewis ◽  
Naomi T. Charles ◽  
Cherysa K.E. Anselm ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Ph Effects ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Phosphotransferase System ◽  
Biofilm Growth ◽  
E Coli ◽  
Low Concentrations ◽  
High Concentrations

We established that <i>Escherichia coli </i>strain 15 (ATCC 9723) produces both curli and cellulose, and forms robust biofilms. Since this strain is wild type with respect to the phosphoenolpyruvate:sugar phosphotransferase system (PTS), it is an ideal strain in which to investigate the effects of the PTS on the biofilm growth of <i>E. coli</i>. We began by looking into the effects of PTS and non-PTS sugars on the biofilm growth of this strain. All the sugars tested tended to activate biofilm growth at low concentrations but to inhibit biofilm growth at high concentrations. Acidification of the medium was an inhibitory factor in the absence of buffer, but buffering to prevent a pH drop did not prevent the inhibitory effects of the sugars. The concentration at which inhibition set in varied from sugar to sugar. For most sugars, cyclic (c)AMP counteracted the inhibition at the lowest inhibitory concentrations but became ineffective at higher concentrations. Our results suggest that cAMP-dependent catabolite repression, which is mediated by the PTS in <i>E. coli</i>, plays a role in the regulation of biofilm growth in response to sugars. cAMP-independent processes, possibly including Cra, also appear to be involved, in addition to pH effects.

Isolation and characterization of catabolite repression-resistant mutants of Escherichia coli

1977 ◽  
Vol 23 (10) ◽  
pp. 1384-1393 ◽  
Author(s):  
Glen D. Armstrong ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Coli Strain ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Isolation And Characterization ◽  
In The Wild ◽  
Resistant Mutants

A method has been developed for the isolation of Escherichia coli mutants which are resistant to catabolite repression. The method is based on the fact that a mixture of glucose and gluconate inhibits the development of chemotactic motility in the wild type, but not in the mutants. A motile E. coli strain was mutagenized and grown in glucose and gluconate. Mutants which were able to swim into a tube containing a chemotactic attractant (aspartic acid) were isolated. Most of these mutants were able to produce β-galactosidase in the presence of glucose and gluconate and were normal in their ability to degrade adenosine 3′,5′-cyclic monophosphate. Some of these mutants were defective in the glucose phosphotransferase system.

scholarly journals Glutathione-Dependent Conversion ofN-Ethylmaleimide to the Maleamic Acid by Escherichia coli: an Intracellular Detoxification Process

2000 ◽  
Vol 66 (4) ◽  
pp. 1393-1399 ◽  
Author(s):  
D. McLaggan ◽  
H. Rufino ◽  
M. Jaspars ◽  
I. R. Booth
Keyword(s):  
Escherichia Coli ◽  
Time Course ◽  
E Coli ◽  
Transient Activation ◽  
Low Concentrations ◽  
Maleamic Acid ◽  
High Concentrations ◽  
Hydrolysis Of ◽  
Strong Activator ◽  
Detoxification Process

ABSTRACT The electrophile N-ethylmaleimide (NEM) elicits rapid K+ efflux from Escherichia coli cells consequent upon reaction with cytoplasmic glutathione to form an adduct, N-ethylsuccinimido-S-glutathione (ESG) that is a strong activator of the KefB and KefC glutathione-gated K+ efflux systems. The fate of the ESG has not previously been investigated. In this report we demonstrate that NEM andN-phenylmaleimide (NPM) are rapidly detoxified by E. coli. The detoxification occurs through the formation of the glutathione adduct of NEM or NPM, followed by the hydrolysis of the imide bond after which N-substituted maleamic acids are released. N-Ethylmaleamic acid is not toxic to E. coli cells even at high concentrations. The glutathione adducts are not released from cells, and this allows glutathione to be recycled in the cytoplasm. The detoxification is independent of new protein synthesis and NAD+-dependent dehydrogenase activity and entirely dependent upon glutathione. The time course of the detoxification of low concentrations of NEM parallels the transient activation of the KefB and KefC glutathione-gated K+ efflux systems.

scholarly journals Alterations in Protein Expression Caused by thehha Mutation in Escherichia coli: Influence of Growth Medium Osmolarity

1999 ◽  
Vol 181 (10) ◽  
pp. 3018-3024 ◽  
Author(s):  
Carlos Balsalobre ◽  
Jörgen Johansson ◽  
Bernt Eric Uhlin ◽  
Antonio Juárez ◽  
Francisco J. Muñoa
Keyword(s):  
Escherichia Coli ◽  
Growth Medium ◽  
Gel Electrophoresis ◽  
Catabolite Repression ◽  
Protein Pattern ◽  
Polyacrylamide Gel Electrophoresis ◽  
Wild Type ◽  
Phosphotransferase System ◽  
New Family ◽  
Medium Osmolarity

ABSTRACT The Hha protein belongs to a new family of regulators involved in the environmental regulation of virulence factors. The aim of this work was to study the effect of the hha mutation on the overall protein pattern of Escherichia coli cells by two-dimensional polyacrylamide gel electrophoresis. The growth medium osmolarity clearly influenced the effect of the hhamutation. The number of proteins whose expression was altered inhha cells, compared with wild-type cells, was three times larger at a high osmolarity than at a low osmolarity. Among the proteins whose expression was modified by the hha allele, both OmpA and protein IIAGlc of the phosphotransferase system could be identified. As this latter enzyme participates in the regulation of the synthesis of cyclic AMP and hence influences the catabolite repression system, we tested whether the expression of thelacZ gene was also modified in hha mutants. This was the case, suggesting that at least some of the pleiotropic effects of the hha mutation could be caused by its effect on the catabolite repression system.

scholarly journals Multiple antibiotic resistance (mar) locus protects Escherichia coli from rapid cell killing by fluoroquinolones.

1996 ◽  
Vol 40 (5) ◽  
pp. 1266-1269 ◽  
Author(s):  
J D Goldman ◽  
D G White ◽  
S B Levy
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Bactericidal Activity ◽  
Cell Killing ◽  
Deletion Mutants ◽  
Multiple Antibiotic Resistance ◽  
Wild Type ◽  
E Coli ◽  
High Concentrations

The multiple antibiotic resistance (mar) locus in Escherichia coli consists of two divergently expressed operons (marC and marRAB), both of which contribute to the Mar phenotype. Overexpression of the marRAB operon protected E. coli against rapid cell killing by fluoroquinolones. Inactivation of the operon in mar mutants restored a wild-type bactericidal susceptibility. Both operons of the locus were required for protection from the quinolone-mediated bactericidal activity in mar locus deletion mutants. The effect was lost at high concentrations of fluoroquinolones, unlike the case for the previously described genes hipA and hipQ. The inducible mar locus appears to specify a novel antibactericidal mechanism which may play a role in the emergence of fluoroquinolone-resistant clinical E. coli isolates.

scholarly journals Identification of a Phosphotransferase System of Escherichia coli Required for Growth on N-Acetylmuramic Acid

2004 ◽  
Vol 186 (8) ◽  
pp. 2385-2392 ◽  
Author(s):  
Ulrike Dahl ◽  
Tina Jaeger ◽  
Bao Trâm Nguyen ◽  
Julia M. Sattler ◽  
Christoph Mayer
Keyword(s):  
Escherichia Coli ◽  
Energy Analysis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Sole Source ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Glucose Transport System ◽  
Single Polypeptide

ABSTRACT We report here that wild-type Escherichia coli grows on N-acetylmuramic acid (MurNAc) as the sole source of carbon and energy. Analysis of mutants defective in N-acetylglucosamine (GlcNAc) catabolism revealed that the catabolic pathway for MurNAc merges into the GlcNAc pathway on the level of GlcNAc 6-phosphate. Furthermore, analysis of mutants defective in components of the phosphotransferase system (PTS) revealed that a PTS is essential for growth on MurNAc. However, neither the glucose-, mannose/glucosamine-, nor GlcNAc-specific PTS (PtsG, ManXYZ, and NagE, respectively) was found to be necessary. Instead, we identified a gene at 55 min on the E. coli chromosome that is responsible for MurNAc uptake and growth. It encodes a single polypeptide consisting of the EIIB and C domains of a so-far-uncharacterized PTS that was named murP. MurP lacks an EIIA domain and was found to require the activity of the crr-encoded enzyme IIA-glucose (EIIAGlc), a component of the major glucose transport system for growth on MurNAc. murP deletion mutants were unable to grow on MurNAc as the sole source of carbon; however, growth was rescued by providing murP in trans expressed from an isopropylthiogalactopyranoside-inducible plasmid. A functional His6 fusion of MurP was constructed, isolated from membranes, and identified as a polypeptide with an apparent molecular mass of 37 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. Close homologs of MurP were identified in the genome of several bacteria, and we believe that these organisms might also be able to utilize MurNAc.

scholarly journals A new spectrophotometric assay for citrate synthase and its use to assess the inhibitory effects of palmitoyl thioesters

1988 ◽  
Vol 251 (3) ◽  
pp. 803-807 ◽  
Author(s):  
A J Else ◽  
S J Barnes ◽  
M J Danson ◽  
P D J Weitzman
Keyword(s):  
Escherichia Coli ◽  
Bacillus Megaterium ◽  
Citrate Synthase ◽  
Spectrophotometric Assay ◽  
Time Dependent ◽  
Inhibitory Effects ◽  
E Coli ◽  
Cell Extracts ◽  
Thioester Bond ◽  
High Concentrations

We have demonstrated that citrate synthase may be assayed by a simple, discontinuous, spectrophotometric procedure based on the measurement of oxaloacetate utilization with 2,4-dinitrophenylhydrazine. The assay is applicable both to the purified enzyme and to cell extracts, and has the advantage that it can be used in the presence of high concentrations of thiols and thioesters. We have used this new assay in part of our investigations into the inhibitory effects of palmitoyl thioesters on diverse citrate synthases. Both palmitoyl-CoA and palmitoyl thioglycollate inhibit citrate synthases from pig heart, Bacillus megaterium and Escherichia coli, the E. coli enzyme showing the greatest sensitivity to these effectors. With palmitoyl-CoA the extent of inhibition is time-dependent, but the enzymes can be protected from the effect by the substrates oxaloacetate and acetyl-CoA. Using the dinitrophenylhydrazine assay, we have shown that the thioester bond is essential for inhibition; that is, if the palmitoyl thioesters are cleaved to give a mixture of palmitate and a thiol compound, the inhibitions of pig heart and B. megaterium citrate synthases are eliminated and that of the E. coli enzyme is markedly decreased.

scholarly journals Effect on solute size on diffusion rates through the transmembrane pores of the outer membrane of Escherichia coli.

1981 ◽  
Vol 77 (2) ◽  
pp. 121-135 ◽  
Author(s):  
H Nikaido ◽  
E Y Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Specific Class ◽  
Wild Type ◽  
Intact Cells ◽  
E Coli ◽  
Low Concentrations ◽  
Transmembrane Pores ◽  
Diffusion Rates ◽  
Type Strains

Nutrients usually cross the outer membrane of Escherichia coli by diffusion through water-filled channels surrounded by a specific class of protein, porins. In this study, the rates of diffusion of hydrophilic nonelectrolytes, mostly sugars and sugar alcohols, through the porin channels were determined in two systems, (a) vesicles reconstituted from phospholipids and purified porin and (b) intact cells of mutant strains that produce many fewer porin molecules than wild-type strains. The diffusion rates were strongly affected by the size of the solute, even when the size was well within the "exclusion limit" of the channel. In both systems, hexoses and hexose disaccharides diffused through the channel at rates 50-80% and 2-4%, respectively, of that of a pentose, arabinose. Application of the Renkin equation to these data led to the estimate that the pore radius is approximately 0.6 nm, if the pore is assumed to be a hollow cylinder. The results of the study also show that the permeability of the outer membrane of the wild-type E. coli cell to glucose and lactose can be explained by the presence of porin channels, that a significant fraction of these channels must be functional or "open" under our conditions of growth, and that even 10(5) channels per cell could become limiting when E. coli tries to grow at a maximal rate on low concentrations of slowly penetrating solutes, such as disaccharides.

scholarly journals Effects of nucleotide substitutions within the T-loop of precursor tRNAs on interaction with ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli and yeast

1996 ◽  
Vol 314 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Zengji LI ◽  
Kimberly A. GILLIS ◽  
Lisa A. HEGG ◽  
Jianchao ZHANG ◽  
David L. THURLOW
Keyword(s):  
Escherichia Coli ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Nucleotide Substitutions ◽  
E Coli ◽  
Naturally Occurring ◽  
Base Substitutions

Recognition of tRNA and tRNA-like substrates by the enzyme ATP/CTP:tRNA nucleotidyltransferase requires chemically intact nucleotides within the T-loop, especially at positions 57 and 58, which are invariant purines among naturally occurring tRNAs. To test the effects of base substitutions at these positions, which are distant from the site of catalysis, we synthesized mutant tRNAGlu molecules. These in vitro-synthesized RNAs also contained an extra 33 bases at the 5´ end and lacked post-transcriptionally modified bases. The precursor tRNAs were used as substrates for nucleotidyltransferases from Escherichia coli and yeast. Substitution of cytidines at either position 57 or 58 had dramatic inhibitory effects on recognition by both enzymes, including raising the apparent Km and lowering the apparent Vmax.; substitution of an adenosine at position 57 or a uridine at position 58 inhibited the reaction only slightly by comparison. Our results demonstrate that the identities of nucleotides at positions 57 and 58 are relevant to recognition by nucleotidyltransferase, and that a purine is required at position 57. The extra bases at the 5´ end and the lack of post-transcriptionally modified bases did not substantially inhibit interaction with the enzyme, as judged by the wild-type precursor tRNAGlu acting as an effective substrate for both enzymes in the presence of equal concentrations of appropriate tRNA substrates isolated from E. coli.

scholarly journals Characterization and nucleotide sequence of the cryptic cel operon of Escherichia coli K12.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 455-471 ◽  
Author(s):  
L L Parker ◽  
B G Hall
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Regulatory Protein ◽  
Wild Type ◽  
Phosphotransferase System ◽  
E Coli ◽  
Significant Homology ◽  
Chromosomal Genes ◽  
Alpha Galactosidase ◽  
Beta Glucosidase

Abstract Wild-type Escherichia coli are not able to utilize beta-glucoside sugars because the genes for utilization of these sugars are cryptic. Spontaneous mutations in the cel operon allow its expression and enable the organism to ferment cellobiose, arbutin and salicin. In this report we describe the structure and nucleotide sequence of the cel operon. The cel operon consists of five genes: celA, whose function is unknown; celB and celC which encode phosphoenolpyruvate-dependent phosphotransferase system enzyme IIcel and enzyme IIIcel, respectively, for the transport and phosphorylation of beta-glucoside sugars; celD, which encodes a negative regulatory protein; and celF, which encodes a phospho-beta-glucosidase that acts on phosphorylated cellobiose, arbutin and salicin. The mutationally activated cel operon is induced in the presence of its substrates, and is repressed in their absence. A comparison of proteins encoded by the cel operon with functionally equivalent proteins of the bgl operon, another cryptic E. coli gene system responsible for the catabolism of beta-glucoside sugars, revealed no significant homology between these two systems despite common functional characteristics. The celD and celF encoded repressor and phospho-beta-glucosidase proteins are homologous to the melibiose regulatory protein and to the melA encoded alpha-galactosidase of E. coli, respectively. Furthermore, the celC encoded PEP-dependent phosphotransferase system enzyme IIIcel is strikingly homologous to an enzyme IIIlac of the Gram-positive organism Staphylococcus aureus. We conclude that the genes for these two enzyme IIIs diverged much more recently than did their hosts, indicating that E. coli and S. aureus have undergone relatively recent exchange of chromosomal genes.

Some biochemical effects of 4-deoxy-4-fluoro-D-glucose on Escherichia coli

1977 ◽  
Vol 55 (8) ◽  
pp. 911-915 ◽  
Author(s):  
N. F. Taylor ◽  
Li-Yu Louie
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Catabolite Repression ◽  
Dry Weight ◽  
Resting Cells ◽  
Phosphotransferase System ◽  
E Coli ◽  
Biochemical Effects ◽  
Inhibition Of Growth ◽  
Uncompetitive Inhibitor

The uptake of 4-deoxy-4-fluoro-D-glucose (4FG), without subsequent catabolism, by resting cells of Escherichia coli (ATCC 11775) is 0.06 mg/mg dry weight. In frozen–thawed cells of this organism, 4FG is a substrate for the phosphoenolpyruvate phosphotransferase system with a rate of phosphorylation twice that found for the isomeric 3-deoxy-3-fluoro-D-glucose. 4FG is not a carbon source for growth of this organism and it inhibits the extent of growth of cells in the presence of glucose. The inhibition of growth of E. coli K12 on lactose by 4FG is also observed and this is considered to be consistent with the fact that 4FG is an uncompetitive inhibitor of β-galactosidase (EC 3.2.1.23) activity and that 4FG or 4-deoxy-4-fluoro-D-glucose-6-phosphate repress β-galactosidase synthesis. These results support the view that catabolite repression may be produced by compounds which are not necessarily metabolised further than hexose-6-phosphates.

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