scholarly journals Polysialic and colanic acids metabolism in Escherichia coli K92 is regulated by RcsA and RcsB

2013 ◽  
Vol 33 (3) ◽  
Author(s):  
Nicolás Navasa ◽  
Leandro Rodríguez-Aparicio ◽  
Miguel Ángel Ferrero ◽  
Andrea Monteagudo-Mera ◽  
Honorina Martínez-Blanco
Keyword(s):  
Escherichia Coli ◽  
Low Temperatures ◽  
Regulatory Mechanism ◽  
Polysialic Acid ◽  
Negative Regulators ◽  
Surface Appearance ◽  
E Coli ◽  
Colanic Acid

We have shown previously that Escherichia coli K92 produces two different capsular polymers known as CA (colanic acid) and PA (polysialic acid) in a thermoregulated manner. The complex Rcs phosphorelay is largely related to the regulation of CA synthesis. Through deletion of rscA and rscB genes, we show that the Rcs system is involved in the regulation of both CA and PA synthesis in E. coli K92. Deletion of either rcsA or rcsB genes resulted in decreased expression of cps (CA biosynthesis cluster) at 19°C and 37°C, but only CA production was reduced at 19°C. Concerning PA, both deletions enhanced its synthesis at 37°C, which does not correlate with the reduced kps (PA biosynthesis cluster) expression observed in the rcsB mutant. Under this condition, expression of the nan operon responsible for PA catabolism was greatly reduced. Although RcsA and RcsB acted as negative regulators of PA synthesis at 37°C, their absence did not reestablish PA expression at low temperatures, despite the deletion of rcsB resulting in enhanced kps expression. Finally, our results revealed that RcsB controlled the expression of several genes (dsrA, rfaH, h-ns and slyA) involved in the thermoregulation of CA and PA synthesis, indicating that RcsB is part of a complex regulatory mechanism governing the surface appearance in E. coli.

scholarly journals Quorum Sensing Is a Global Regulatory Mechanism in Enterohemorrhagic Escherichia coli O157:H7

2001 ◽  
Vol 183 (17) ◽  
pp. 5187-5197 ◽  
Author(s):  
Vanessa Sperandio ◽  
Alfredo G. Torres ◽  
Jorge A. Girón ◽  
James B. Kaper
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Mechanism ◽  
Sos Response ◽  
Enterohemorrhagic Escherichia Coli ◽  
Trna Genes ◽  
Wild Type ◽  
E Coli

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for outbreaks of bloody diarrhea and hemolytic-uremic syndrome in many countries. EHEC virulence mechanisms include the production of Shiga toxins (Stx) and formation of attaching and effacing (AE) lesions on intestinal epithelial cells. We recently reported that genes involved in the formation of the AE lesion were regulated by quorum sensing through autoinducer-2, which is synthesized by the product of the luxS gene. In this study we hybridized an E. coli gene array with cDNA synthesized from RNA that was extracted from EHEC strain 86-24 and its isogenicluxS mutant. We observed that 404 genes were regulated by luxS at least fivefold, which comprises approximately 10% of the array genes; 235 of these genes were up-regulated and 169 were down-regulated in the wild-type strain compared to in theluxS mutant. Down-regulated genes included several involved in cell division, as well as ribosomal and tRNA genes. Consistent with this pattern of gene expression, theluxS mutant grows faster than the wild-type strain (generation times of 37.5 and 60 min, respectively, in Dulbecco modified Eagle medium). Up-regulated genes included several involved in the expression and assembly of flagella, motility, and chemotaxis. Using operon::lacZ fusions to class I, II, and III flagellar genes, we were able to confirm this transcriptional regulation. We also observed fewer flagella by Western blotting and electron microscopy and decreased motility halos in semisolid agar in the luxS mutant. The average swimming speeds for the wild-type strain and the luxS mutant are 12.5 and 6.6 μm/s, respectively. We also observed an increase in the production of Stx due to quorum sensing. Genes encoding Stx, which are transcribed along with λ-like phage genes, are induced by an SOS response, and genes involved in the SOS response were also regulated by quorum sensing. These results indicate that quorum sensing is a global regulatory mechanism for basic physiological functions of E. coli as well as for virulence factors.

scholarly journals Escherichia coli Harboring a Natural IncF Conjugative F Plasmid Develops Complex Mature Biofilms by Stimulating Synthesis of Colanic Acid and Curli

2008 ◽  
Vol 190 (22) ◽  
pp. 7479-7490 ◽  
Author(s):  
Thithiwat May ◽  
Satoshi Okabe
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Three Dimensional ◽  
F Plasmid ◽  
Form Complex ◽  
Global Regulators ◽  
E Coli ◽  
Colanic Acid ◽  
Regulatory Systems ◽  
Initial Deposition

ABSTRACT It has been shown that Escherichia coli harboring the derepressed IncFI and IncFII conjugative F plasmids form complex mature biofilms by using their F-pilus connections, whereas a plasmid-free strain forms only patchy biofilms. Therefore, in this study we investigated the contribution of a natural IncF conjugative F plasmid to the formation of E. coli biofilms. Unlike the presence of a derepressed F plasmid, the presence of a natural IncF F plasmid promoted biofilm formation by generating the cell-to-cell mating F pili between pairs of F+ cells (approximately two to four pili per cell) and by stimulating the formation of colanic acid and curli meshwork. Formation of colanic acid and curli was required after the initial deposition of F-pilus connections to generate a three-dimensional mushroom-type biofilm. In addition, we demonstrated that the conjugative factor of F plasmid, rather than a pilus synthesis function, was involved in curli production during biofilm formation, which promoted cell-surface interactions. Curli played an important role in the maturation process. Microarray experiments were performed to identify the genes involved in curli biosynthesis and regulation. The results suggested that a natural F plasmid was more likely an external activator that indirectly promoted curli production via bacterial regulatory systems (the EnvZ/OmpR two-component regulators and the RpoS and HN-S global regulators). These data provided new insights into the role of a natural F plasmid during the development of E. coli biofilms.

scholarly journals Global Lysine Acetylation in Escherichia coli Results from Growth Conditions That Favor Acetate Fermentation

2019 ◽  
Vol 201 (9) ◽  
Author(s):  
Birgit Schilling ◽  
Nathan Basisty ◽  
David G. Christensen ◽  
Dylan Sorensen ◽  
James S. Orr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Regulatory Mechanism ◽  
Growth Conditions ◽  
Lysine Acetylation ◽  
Label Free ◽  
Content Type ◽  
E Coli ◽  
Regulatory Mode ◽  
Specific Sugar

ABSTRACT Lysine acetylation is thought to provide a mechanism for regulating metabolism in diverse bacteria. Indeed, many studies have shown that the majority of enzymes involved in central metabolism are acetylated and that acetylation can alter enzyme activity. However, the details regarding this regulatory mechanism are still unclear, specifically with regard to the signals that induce lysine acetylation. To better understand this global regulatory mechanism, we profiled changes in lysine acetylation during growth of Escherichia coli on the hexose glucose or the pentose xylose at both high and low sugar concentrations using label-free mass spectrometry. The goal was to see whether lysine acetylation differed during growth on these two different sugars. No significant differences, however, were observed. Rather, the initial sugar concentration was the principal factor governing changes in lysine acetylation, with higher sugar concentrations causing more acetylation. These results suggest that acetylation does not target specific metabolic pathways but rather simply targets accessible lysines, which may or may not alter enzyme activity. They further suggest that lysine acetylation principally results from conditions that favor accumulation of acetyl phosphate, the principal acetate donor in E. coli. IMPORTANCE Bacteria alter their metabolism in response to nutrient availability, growth conditions, and environmental stresses using a number of different mechanisms. One is lysine acetylation, a posttranslational modification known to target many metabolic enzymes. However, little is known about this regulatory mode. We investigated the factors inducing changes in lysine acetylation by comparing growth on glucose and xylose. We found that the specific sugar used for growth did not alter the pattern of acetylation; rather, the amount of sugar did, with more sugar causing more acetylation. These results imply that lysine acetylation is a global regulatory mechanism that is responsive not to the specific carbon source per se but rather to the accumulation of downstream metabolites.

scholarly journals Structural analysis of colanic acid from Escherichia coli by using methylation and base-catalysed fragmentation. Comparison with polysaccharides from other bacterial sources

1969 ◽  
Vol 115 (5) ◽  
pp. 947-958 ◽  
Author(s):  
C. J. Lawson ◽  
C. W. McCleary ◽  
Henry I. Nakada ◽  
D. A. Rees ◽  
I. W. Sutherland ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pyruvic Acid ◽  
Hydrolysis Product ◽  
Acid Methyl Ester ◽  
Extracellular Polysaccharide ◽  
Partial Hydrolysis ◽  
Capsular Polysaccharides ◽  
E Coli ◽  
Colanic Acid ◽  
Bacterial Sources

Essentially the same methanolysis products were obtained after methylation of the slime and capsular polysaccharides from Escherichia coli K12 (S53 and S53C sub-strains) and the slime polysaccharides from E. coli K12 (S61), Aerobacter cloacae N.C.T.C. 5290 and Salmonella typhimurium SL1543. These were the methyl glycosides of 2-O-methyl-l-fucose, 2,3-di-O-methyl-l-fucose, 2,3-di-O-methyl-d-glucuronic acid methyl ester, 2,4,6-tri-O-methyl-d-glucose, 2,4,6-tri-O-methyl-d-galactose and the pyruvic acid ketal, 4,6-O-(1′-methoxycarbonylethylidene)-2,3-O-methyl-d-galactose. All were identified as crystalline derivatives from an E. coli polysaccharide. The structure of the ketal was proved by proton-magnetic-resonance and mass spectrometry, and by cleavage to pyruvic acid and 2,3-di-O-methyl-d-galactose. All these polysaccharides are therefore regarded as variants on the same fundamental structure for which the name colanic acid is adopted. Although containing the same sugar residues, quite different methanolysis products were obtained after methylation of the extracellular polysaccharide from Klebsiella aerogenes (1.2 strain). The hydroxypropyl ester of E. coli polysaccharide, when treated with base under anhydrous conditions, underwent β-elimination at the uronate residues with release of a 4,6-O-(1′-alkoxycarbonylethylidene)-d-galactose. Together with the identification of 3-O-(d-glucopyranosyluronic acid)-d-galactose as a partial hydrolysis product, this establishes the nature of most, if not all, of the side chains as O-[4,6-O-(1′-carboxyethylidene)-d-galactopyranosyl]-(1→4)-O-(d-glucopyranosyluronic acid)-(1→3)-d-galactopyranosyl…

scholarly journals Prevention and Cure of Systemic Escherichia coli K1 Infection by Modification of the Bacterial Phenotype

2004 ◽  
Vol 48 (5) ◽  
pp. 1503-1508 ◽  
Author(s):  
Naseem Mushtaq ◽  
Maria B. Redpath ◽  
J. Paul Luzio ◽  
Peter W. Taylor
Keyword(s):  
Escherichia Coli ◽  
Capsular Polysaccharide ◽  
Virulent Strain ◽  
Polysialic Acid ◽  
Intraperitoneal Administration ◽  
Systemic Infection ◽  
E Coli ◽  
Inhibition Of Growth ◽  
Old Rats ◽  
Prevention And Cure

ABSTRACT Escherichia coli is a common cause of meningitis and sepsis in the newborn infant, and the large majority of isolates from these infections produce a polysialic acid (PSA) capsular polysaccharide, the K1 antigen, that protects the bacterial cell from immune attack. We determined whether a capsule-depolymerizing enzyme, by removing this protective barrier, could alter the outcome of systemic infection in an animal model. Bacteriophage-derived endosialidase E (endoE) selectively degrades the PSA capsule on the surface of E. coli K1 strains. Intraperitoneal administration of small quantities of recombinant endoE (20 μg) to 3-day-old rats, colonized with a virulent strain of K1, prevented bacteremia and death from systemic infection. The enzyme had no effect on the viability of E. coli strains but sensitized strains expressing PSA to killing by the complement system. This study demonstrates the potential therapeutic efficacy of agents that cure infections by modification of the bacterial phenotype rather than by killing or inhibition of growth of the pathogen.

scholarly journals Polysaccharides Cellulose, Poly-β-1,6-N-Acetyl-d-Glucosamine, and Colanic Acid Are Required for Optimal Binding of Escherichia coli O157:H7 Strains to Alfalfa Sprouts and K-12 Strains to Plastic but Not for Binding to Epithelial Cells

2008 ◽  
Vol 74 (8) ◽  
pp. 2384-2390 ◽  
Author(s):  
Ann G. Matthysse ◽  
Rajendar Deora ◽  
Meenu Mishra ◽  
Alfredo G. Torres
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cells ◽  
Capsular Polysaccharide ◽  
Cellulose Synthase ◽  
Marginal Effect ◽  
Tomato Root ◽  
E Coli ◽  
Colanic Acid ◽  
Alfalfa Sprouts ◽  
K 12

ABSTRACT When Escherichia coli O157:H7 bacteria are added to alfalfa sprouts growing in water, the bacteria bind tightly to the sprouts. In contrast, laboratory K-12 strains of E. coli do not bind to sprouts under similar conditions. The roles of E. coli O157:H7 lipopolysaccharide (LPS), capsular polysaccharide, and exopolysaccharides in binding to sprouts were examined. An LPS mutant had no effect on the binding of the pathogenic strain. Cellulose synthase mutants showed a significant reduction in binding; colanic acid mutants were more severely reduced, and binding by poly-β-1,6-N-acetylglucosamine (PGA) mutants was barely detectable. The addition of a plasmid carrying a cellulose synthase gene to K-12 strains allowed them to bind to sprouts. A plasmid carrying the Bps biosynthesis genes had only a marginal effect on the binding of K-12 bacteria. However, the introduction of the same plasmid allowed Sinorhizobium meliloti and a nonbinding mutant of Agrobacterium tumefaciens to bind to tomato root segments. These results suggest that although multiple redundant protein adhesins are involved in the binding of E. coli O157:H7 to sprouts, the polysaccharides required for binding are not redundant and each polysaccharide may play a distinct role. PGA, colanic acid, and cellulose were also required for biofilm formation by a K-12 strain on plastic, but not for the binding of E. coli O157:H7 to mammalian cells.

scholarly journals Global lysine acetylation in Escherichia coli results from growth conditions that favor acetate fermentation

2018 ◽  
Author(s):  
Birgit Schilling ◽  
Nathan Basisty ◽  
David G. Christensen ◽  
Dylan Sorensen ◽  
James S. Orr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Transcriptional Regulation ◽  
Regulatory Mechanism ◽  
Growth Conditions ◽  
Principal Factor ◽  
Lysine Acetylation ◽  
Label Free ◽  
Post Translational Modification ◽  
E Coli

ABSTRACTLysine acetylation is thought to provide a mechanism for regulating metabolism in diverse bacteria. Indeed, many studies have shown that the majority of enzymes involved in central metabolism are acetylated and that acetylation can alter enzyme activity. However, the details regarding this regulatory mechanism are still unclear, specifically with regards to the signals that induce lysine acetylation. To better understand this global regulatory mechanism, we profiled changes in lysine acetylation during growth of Escherichia coli on the hexose glucose or the pentose xylose at both high and low sugar concentrations using label-free mass spectrometry. The goal was to see whether lysine acetylation differed during growth on these two different sugars. No significant differences, however, were observed. Rather, the initial sugar concentration was the principal factor governing changes in lysine acetylation, with higher sugar concentrations causing more acetylation. These results suggest that acetylation does not target specific metabolic pathways but rather simply targets accessible lysines, which may or may not alter enzyme activity. They further suggest that lysine acetylation principally results from conditions that favor accumulation of acetyl phosphate, the principal acetate donor in E. coli.IMPORTANCEBacteria alter their metabolism in response to nutrient availability, growth conditions, and environmental stresses. This process is best understood at the level of transcriptional regulation, where many metabolic genes are conditionally expressed in response to diverse cues. However, additional modes of regulations are known to exist. One is lysine acetylation, a post-translational modification known to target many metabolic enzymes. However, unlike transcriptional regulation, little is known about this regulatory mode. We investigated the factors inducing changes in lysine acetylation by comparing growth on glucose and xylose. We found that the specific sugar used for growth did not alter the pattern of acetylation; rather, the principal factor was the amount of sugar, with more sugar yielding more acetylation. These results imply lysine acetylation is a global regulatory mechanism that is not responsive to the specific carbon source per se but rather the accumulation of downstream metabolites.

scholarly journals O -Acetylation of Capsular Polysialic Acid Enables Escherichia coli K1 Escaping from Siglec-Mediated Innate Immunity and Lysosomal Degradation of E. coli -Containing Vacuoles in Macrophage-Like Cells

2021 ◽  
Author(s):  
Jinghua Yang ◽  
Wei Ma ◽  
Yuanyuan Wu ◽  
Hui Zhou ◽  
Siyu Song ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Innate Immunity ◽  
Antibiotic Therapy ◽  
Polysialic Acid ◽  
Neonatal Meningitis ◽  
Lysosomal Degradation ◽  
Content Type ◽  
Mortality And Morbidity ◽  
E Coli ◽  
Escherichia Coli K1

Escherichia coli K1 is a leading cause of neonatal meningitis. The mortality and morbidity of this disease remain significantly high despite antibiotic therapy.

scholarly journals Gene Products Required for De Novo Synthesis of Polysialic Acid in Escherichia coli K1

2006 ◽  
Vol 188 (5) ◽  
pp. 1786-1797 ◽  
Author(s):  
Ekaterina N. Andreishcheva ◽  
Willie F. Vann
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
De Novo ◽  
Polysialic Acid ◽  
Neonatal Meningitis ◽  
Gene Products ◽  
De Novo Synthesis ◽  
E Coli ◽  
Tract Infections

ABSTRACT Escherichia coli K1 is responsible for 80% of E. coli neonatal meningitis and is a common pathogen in urinary tract infections. Bacteria of this serotype are encapsulated with the α(2-8)-polysialic acid NeuNAc(α2-8), common to several bacterial pathogens. The gene cluster encoding the pathway for synthesis of this polymer is organized into three regions: (i) kpsSCUDEF, (ii) neuDBACES, and (iii) kpsMT. The K1 polysialyltransferase, NeuS, cannot synthesize polysialic acid de novo without other products of the gene cluster. Membranes isolated from strains having the entire K1 gene cluster can synthesize polysialic acid de novo. We designed a series of plasmid constructs containing fragments of regions 1 and 2 in two compatible vectors to determine the minimum number of gene products required for de novo synthesis of the polysialic acid from CMP-NeuNAc in K1 E. coli. We measured the ability of the various combinations of region 1 and 2 fragments to restore polysialyltransferase activity in vitro in the absence of exogenously added polysaccharide acceptor. The products of region 2 genes neuDBACES alone were not sufficient to support de novo synthesis of polysialic acid in vitro. Only membrane fractions harboring NeuES and KpsCS could form sialic polymer in the absence of exogenous acceptor at the concentrations formed by wild-type E. coli K1 membranes. Membrane fractions harboring NeuES and KpsC together could form small quantities of the sialic polymer de novo.

Survival of Escherichia coli O157:H7 in Set Yogurt as Influenced by the Production of an Exopolysaccharide, Colanic Acid

2004 ◽  
Vol 67 (2) ◽  
pp. 252-255 ◽  
Author(s):  
SHIAO MEI LEE ◽  
JINRU CHEN
Keyword(s):  
Escherichia Coli ◽  
Culture Media ◽  
Starter Cultures ◽  
Escherichia Coli O157 ◽  
Acidic Polysaccharide ◽  
E Coli ◽  
Colanic Acid ◽  
Plate Counts ◽  
Processing And Storage ◽  
And Storage

Previous studies conducted in our laboratory revealed that Escherichia coli O157:H7 cells capable of producing colanic acid (CA), the acidic polysaccharide of mucoid slime, had increased tolerance to sublethal heat and the extreme pH of microbiological culture media. This study was undertaken to determine the effect of CA on the fate of E. coli O157:H7 during the processing and storage of an acid food: yogurt. Pasteurized and homogenized whole milk was inoculated with a wild-type E. coli O157:H7, its CA-deficient mutant, or a mixture (1:1) of the two strains. Set yogurt was processed from the contaminated milk and stored at 4° and 15°C for 3 weeks. Samples of milk and yogurt were withdrawn during processing and storage and analyzed for total plate counts and populations of E. coli O157:H7 and starter cultures. The results showed that E. coli O157: H7 survived longer in yogurt stored at 15°C than at 4°C. Cells of E. coli O157:H7 deficient in CA production died off more rapidly than those of the parent strain. This suggests that CA plays a role in protecting cells of E. coli O157:H7 from stress during the processing and storage of set yogurt.

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