scholarly journals The Csr System Regulates Escherichia coli Fitness by Controlling Glycogen Accumulation and Energy Levels

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Manon Morin ◽  
Delphine Ropers ◽  
Eugenio Cinquemani ◽  
Jean-Charles Portais ◽  
Brice Enjalbert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Posttranscriptional Regulation ◽  
Energy Levels ◽  
Regulatory System ◽  
Metabolic Adaptation ◽  
Glycogen Accumulation ◽  
E Coli ◽  
Sufficient Energy ◽  
First Time

ABSTRACT In the bacterium Escherichia coli, the posttranscriptional regulatory system Csr was postulated to influence the transition from glycolysis to gluconeogenesis. Here, we explored the role of the Csr system in the glucose-acetate transition as a model of the glycolysis-to-gluconeogenesis switch. Mutations in the Csr system influence the reorganization of gene expression after glucose exhaustion and disturb the timing of acetate reconsumption after glucose exhaustion. Analysis of metabolite concentrations during the transition revealed that the Csr system has a major effect on the energy levels of the cells after glucose exhaustion. This influence was demonstrated to result directly from the effect of the Csr system on glycogen accumulation. Mutation in glycogen metabolism was also demonstrated to hinder metabolic adaptation after glucose exhaustion because of insufficient energy. This work explains how the Csr system influences E. coli fitness during the glycolysis-gluconeogenesis switch and demonstrates the role of glycogen in maintenance of the energy charge during metabolic adaptation. IMPORTANCE Glycogen is a polysaccharide and the main storage form of glucose from bacteria such as Escherichia coli to yeasts and mammals. Although its function as a sugar reserve in mammals is well documented, the role of glycogen in bacteria is not as clear. By studying the role of posttranscriptional regulation during metabolic adaptation, for the first time, we demonstrate the role of sugar reserve played by glycogen in E. coli. Indeed, glycogen not only makes it possible to maintain sufficient energy during metabolic transitions but is also the key component in the capacity of cells to resume growth. Since the essential posttranscriptional regulatory system Csr is a major regulator of glycogen accumulation, this work also sheds light on the central role of posttranscriptional regulation in metabolic adaptation. IMPORTANCE Glycogen is a polysaccharide and the main storage form of glucose from bacteria such as Escherichia coli to yeasts and mammals. Although its function as a sugar reserve in mammals is well documented, the role of glycogen in bacteria is not as clear. By studying the role of posttranscriptional regulation during metabolic adaptation, for the first time, we demonstrate the role of sugar reserve played by glycogen in E. coli. Indeed, glycogen not only makes it possible to maintain sufficient energy during metabolic transitions but is also the key component in the capacity of cells to resume growth. Since the essential posttranscriptional regulatory system Csr is a major regulator of glycogen accumulation, this work also sheds light on the central role of posttranscriptional regulation in metabolic adaptation.

scholarly journals Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

2013 ◽  
Vol 81 (4) ◽  
pp. 1164-1171 ◽  
Author(s):  
Erik J. Boll ◽  
Carsten Struve ◽  
Nadia Boisen ◽  
Bente Olesen ◽  
Steen G. Stahlhut ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Outbreak Strain ◽  
Content Type ◽  
E Coli ◽  
Abiotic Surfaces ◽  
Extraintestinal Disease ◽  
First Time ◽  
Specific Virulence

ABSTRACTA multiresistant clonalEscherichia coliO78:H10 strain qualifying molecularly as enteroaggregativeEscherichia coli(EAEC) was recently shown to be the cause of a community-acquired outbreak of urinary tract infection (UTI) in greater Copenhagen, Denmark, in 1991. This marks the first time EAEC has been associated with an extraintestinal disease outbreak. Importantly, the outbreak isolates were recovered from the urine of patients with symptomatic UTI, strongly implying urovirulence. Here, we sought to determine the uropathogenic properties of the Copenhagen outbreak strain and whether these properties are conferred by the EAEC-specific virulence factors. We demonstrated that through expression of aggregative adherence fimbriae, the principal adhesins of EAEC, the outbreak strain exhibited pronouncedly increased adherence to human bladder epithelial cells compared to prototype uropathogenic strains. Moreover, the strain was able to produce distinct biofilms on abiotic surfaces, including urethral catheters. These findings suggest that EAEC-specific virulence factors increase uropathogenicity and may have played a significant role in the ability of the strain to cause a community-acquired outbreak of UTI. Thus, inclusion of EAEC-specific virulence factors is warranted in future detection and characterization of uropathogenicE. coli.

scholarly journals Contribution of the Ler- and H-NS-Regulated Long Polar Fimbriae of Escherichia coli O157:H7 during Binding to Tissue-Cultured Cells

2008 ◽  
Vol 76 (11) ◽  
pp. 5062-5071 ◽  
Author(s):  
Alfredo G. Torres ◽  
Terry M. Slater ◽  
Shilpa D. Patel ◽  
Vsevolod L. Popov ◽  
Margarita M. P. Arenas-Hernández
Keyword(s):  
Escherichia Coli ◽  
Cultured Cells ◽  
Immunogold Labeling ◽  
Regulatory Sequence ◽  
Escherichia Coli O157 ◽  
Wild Type ◽  
E Coli ◽  
First Time ◽  
Better Than

ABSTRACT The expression of the long polar fimbriae (LPF) of enterohemorrhagic Escherichia coli (EHEC) O157:H7 is controlled by a tightly regulated process, and, therefore, the role of these fimbriae during binding to epithelial cells has been difficult to establish. We recently found that histone-like nucleoid-structuring protein (H-NS) binds to the regulatory sequence of the E. coli O157:H7 lpf1 operon and “silences” its transcription, while Ler inhibits the action of the H-NS protein and allows lpf1 to be expressed. In the present study, we determined how the deregulated expression of LPF affects binding of EHEC O157:H7 to tissue-cultured cells, correlating the adherence phenotype with lpf1 expression. We tested the adherence properties of EHEC hns mutant and found that this strain adhered 2.8-fold better than the wild type. In contrast, the EHEC ler mutant adhered 2.1-fold less than the wild type. The EHEC hns ler mutant constitutively expressed the lpf genes, and, therefore, we observed that the double mutant adhered 5.6-fold times better than the wild type. Disruption of lpfA in the EHEC hns and hns ler mutants or the addition of anti-LpfA serum caused a reduction in adhesion, demonstrating that the increased adherence was due to the expression of LPF. Immunogold-labeling electron microscopy showed that LPF is present on the surface of EHEC lpfA + strains. Furthermore, we showed that EHEC expressing LPF agglutinates red blood cells from different species and that the agglutination was blocked by the addition of anti-LpfA serum. Overall, our data confirmed that expression of LPF is a tightly regulated process and, for the first time, demonstrated that these fimbriae are associated with adherence and hemagglutination phenotypes in EHEC O157:H7.

scholarly journals DEGR-factor Xa blocks disseminated intravascular coagulation initiated by Escherichia coli without preventing shock or organ damage

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 364-368 ◽  
Author(s):  
FB Jr Taylor ◽  
AC Chang ◽  
GT Peer ◽  
T Mather ◽  
K Blick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Injury ◽  
Factor Xa ◽  
Organ Damage ◽  
Lethal Outcome ◽  
Chloromethyl Ketone ◽  
E Coli ◽  
And Control ◽  
First Time

One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1- naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

scholarly journals DEGR-factor Xa blocks disseminated intravascular coagulation initiated by Escherichia coli without preventing shock or organ damage

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 364-368 ◽  
Author(s):  
FB Jr Taylor ◽  
AC Chang ◽  
GT Peer ◽  
T Mather ◽  
K Blick ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Injury ◽  
Factor Xa ◽  
Organ Damage ◽  
Lethal Outcome ◽  
Chloromethyl Ketone ◽  
E Coli ◽  
And Control ◽  
First Time

Abstract One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1- naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

scholarly journals Roles of the C-Terminal Amino Acids of Non-Hexameric Helicases: Insights from Escherichia coli UvrD

2021 ◽  
Vol 22 (3) ◽  
pp. 1018
Author(s):  
Hiroaki Yokota
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Single Molecule ◽  
Underlying Mechanism ◽  
Amino Acid Sequences ◽  
E Coli ◽  
X Ray Crystallography ◽  
Terminal Amino

Helicases are nucleic acid-unwinding enzymes that are involved in the maintenance of genome integrity. Several parts of the amino acid sequences of helicases are very similar, and these quite well-conserved amino acid sequences are termed “helicase motifs”. Previous studies by X-ray crystallography and single-molecule measurements have suggested a common underlying mechanism for their function. These studies indicate the role of the helicase motifs in unwinding nucleic acids. In contrast, the sequence and length of the C-terminal amino acids of helicases are highly variable. In this paper, I review past and recent studies that proposed helicase mechanisms and studies that investigated the roles of the C-terminal amino acids on helicase and dimerization activities, primarily on the non-hexermeric Escherichia coli (E. coli) UvrD helicase. Then, I center on my recent study of single-molecule direct visualization of a UvrD mutant lacking the C-terminal 40 amino acids (UvrDΔ40C) used in studies proposing the monomer helicase model. The study demonstrated that multiple UvrDΔ40C molecules jointly participated in DNA unwinding, presumably by forming an oligomer. Thus, the single-molecule observation addressed how the C-terminal amino acids affect the number of helicases bound to DNA, oligomerization, and unwinding activity, which can be applied to other helicases.

scholarly journals Distribution of Lactoferrin Is Related with Dynamics of Neutrophils in Bacterial Infected Mice Intestine

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1496 ◽  
Author(s):  
Li Liang ◽  
Zhen-Jie Wang ◽  
Guang Ye ◽  
Xue-You Tang ◽  
Yuan-Yuan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Mucosal Immunity ◽  
Mrna Levels ◽  
Iron Binding ◽  
E Coli ◽  
New Knowledge ◽  
Activated Neutrophils ◽  
Binding Glycoprotein

Lactoferrin (Lf) is a conserved iron-binding glycoprotein with antimicrobial activity, which is present in secretions that recover mucosal sites regarded as portals of invaded pathogens. Although numerous studies have focused on exogenous Lf, little is known about its expression of endogenous Lf upon bacterial infection. In this study, we investigated the distribution of Lf in mice intestine during Escherichia coli (E. coli) K88 infection. PCR and immunohistology staining showed that mRNA levels of Lf significantly increased in duodenum, ileum and colon, but extremely decreased in jejunum at 8 h and 24 h after infection. Meanwhile, endogenous Lf was mostly located in the lamina propria of intestine villi, while Lf receptor (LfR) was in the crypts. It suggested that endogenous Lf-LfR interaction might not be implicated in the antibacterial process. In addition, it was interesting to find that the infiltration of neutrophils into intestine tissues was changed similarly to Lf expression. It indicated that the variations of Lf expression were rather due to an equilibrium between the recruitment of neutrophils and degranulation of activated neutrophils. Thus, this new knowledge will pave the way to a more effective understanding of the role of Lf in intestinal mucosal immunity.

SATP (YaaH), a succinate–acetate transporter protein in Escherichia coli

2013 ◽  
Vol 454 (3) ◽  
pp. 585-595 ◽  
Author(s):  
Joana Sá-Pessoa ◽  
Sandra Paiva ◽  
David Ribas ◽  
Inês Jesus Silva ◽  
Sandra Cristina Viegas ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Succinic Acid ◽  
Critical Role ◽  
Amino Acid Residues ◽  
E Coli ◽  
Transporter Protein ◽  
Affinity Constants ◽  
In Trans

In the present paper we describe a new carboxylic acid transporter in Escherichia coli encoded by the gene yaaH. In contrast to what had been described for other YaaH family members, the E. coli transporter is highly specific for acetic acid (a monocarboxylate) and for succinic acid (a dicarboxylate), with affinity constants at pH 6.0 of 1.24±0.13 mM for acetic acid and 1.18±0.10 mM for succinic acid. In glucose-grown cells the ΔyaaH mutant is compromised for the uptake of both labelled acetic and succinic acids. YaaH, together with ActP, described previously as an acetate transporter, affect the use of acetic acid as sole carbon and energy source. Both genes have to be deleted simultaneously to abolish acetate transport. The uptake of acetate and succinate was restored when yaaH was expressed in trans in ΔyaaH ΔactP cells. We also demonstrate the critical role of YaaH amino acid residues Leu131 and Ala164 on the enhanced ability to transport lactate. Owing to its functional role in acetate and succinate uptake we propose its assignment as SatP: the Succinate–Acetate Transporter Protein.

scholarly journals Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kayhan Ilbeigi ◽  
Mahdi Askari Badouei ◽  
Hossein Vaezi ◽  
Hassan Zaheri ◽  
Sina Aghasharif ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Companion Animals ◽  
Multidrug Resistant ◽  
Animal Origin ◽  
Colistin Resistance ◽  
E Coli ◽  
High Level ◽  
Farming Industry

Abstract Objectives The emergence of colistin-resistant Enterobacteriaceae from human and animal sources is one of the major public health concerns as colistin is the last-resort antibiotic for treating infections caused by multidrug-resistant Gram-negative bacteria. We aimed to determine the prevalence of the prototype widespread colistin resistance genes (mcr-1 and mcr-2) among commensal and pathogenic Escherichia coli strains isolated from food-producing and companion animals in Iran. Results A total of 607 E. coli isolates which were previously collected from different animal sources between 2008 and 2016 used to uncover the possible presence of plasmid-mediated colistin resistance genes (mcr-1 and mcr-2) by PCR. Overall, our results could not confirm the presence of any mcr-1 or mcr-2 positive E. coli among the studied isolates. It is concluded that despite the important role of food-producing animals in transferring the antibiotic resistance, they were not the main source for carriage of mcr-1 and mcr-2 in Iran until 2016. This study suggests that the other mcr variants (mcr-3 to mcr-9) might be responsible for conferring colistin resistance in animal isolates in Iran. The possible linkage between pig farming industry and high level of mcr carriage in some countries needs to be clarified in future prospective studies.

scholarly journals Drinking water and diarrhoeal disease due to Escherichia coli

2003 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Paul R. Hunter
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Clinical Presentation ◽  
Diarrhoeal Disease ◽  
Central Place ◽  
E Coli ◽  
Related Disease ◽  
Direct Damage ◽  
Water Microbiology

Escherichia coli has had a central place in water microbiology for decades as an indicator of faecal pollution. It is only relatively recently that the role of E. coli as pathogen, rather than indicator, in drinking water has begun to be stressed. Interest in the role of E. coli as a cause of diarrhoeal disease has increased because of the emergence of E. coli O157:H7 and other enterohaemorrhagic E. coli, due to the severity of the related disease. There are enterotoxigenic, enteropathogenic, enterohaemorrhagic, enteroinvasive, enteroaggregative and diffusely adherent strains of E. coli. Each type of E. coli causes diarrhoeal disease through different mechanisms and each causes a different clinical presentation. Several of the types cause diarrhoea by the elaboration of one or more toxins, others by some other form of direct damage to epithelial cells. This paper discusses each of these types in turn and also describes their epidemiology, with particular reference to whether they are waterborne or not.

Quantitative Determination of the Role of Lettuce Leaf Structures in Protecting Escherichia coli O157:H7 from Chlorine Disinfection

2001 ◽  
Vol 64 (2) ◽  
pp. 147-151 ◽  
Author(s):  
KAZUE TAKEUCHI ◽  
JOSEPH F. FRANK
Keyword(s):  
Escherichia Coli ◽  
Leaf Surface ◽  
Dead Cell ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Chlorine Disinfection ◽  
Sytox Green ◽  
Tissue Surface ◽  
Confocal Scanning

Viability of Escherichia coli O157:H7 cells on lettuce leaves after 200 mg/liter (200 ppm) chlorine treatment and the role of lettuce leaf structures in protecting cells from chlorine inactivation were evaluated by confocal scanning microscopy (CSLM). Lettuce samples (2 by 2 cm) were inoculated by immersing in a suspension containing 109 CFU/ml of E. coli O157: H7 for 24 ± 1 h at 4°C. Rinsed samples were treated with 200 mg/liter (200 ppm) chlorine for 5 min at 22°C. Viability of E. coli O157:H7 cells was evaluated by CSLM observation of samples stained with Sytox green (dead cell stain) and Alexa 594 conjugated antibody against E. coli O157:H7. Quantitative microscopic observations of viability were made at intact leaf surface, stomata, and damaged tissue. Most E. coli O157:H7 cells (68.3 ± 16.2%) that had penetrated 30 to 40 μm from the damaged tissue surface remained viable after chlorine treatment. Cells on the surface survived least (25.2 ± 15.8% survival), while cells that penetrated 0 to 10 μm from the damaged tissue surface or entered stomata showed intermediate survival (50.8 ± 13.5 and 45.6 ± 9.7% survival, respectively). Viability was associated with the depth at which E. coli O157:H7 cells were in the stomata. Although cells on the leaf surface were mostly inactivated, some viable cells were observed in cracks of cuticle and on the trichome. These results demonstrate the importance of lettuce leaf structures in the protection of E. coli O157:H7 cells from chlorine inactivation.

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