Overproduction of Exopolysaccharide Colanic Acid by Escherichia coli by Strain Engineering and Media Optimization

2020 ◽  
Vol 193 (1) ◽  
pp. 111-127
Author(s):  
Hyeong Min Han ◽  
In Jung Kim ◽  
Eun Ju Yun ◽  
Jae Won Lee ◽  
Yoonho Cho ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Strain Engineering ◽  
Media Optimization ◽  
Colanic Acid

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 Activation of the gab Operon in an RpoS-Dependent Manner by Mutations That Truncate the Inner Core of Lipopolysaccharide in Escherichia coli

2004 ◽  
Vol 186 (24) ◽  
pp. 8542-8546 ◽  
Author(s):  
Moses L. Joloba ◽  
Katy M. Clemmer ◽  
Darren D. Sledjeski ◽  
Philip N. Rather
Keyword(s):  
Escherichia Coli ◽  
Sigma Factor ◽  
Inner Core ◽  
Acid Synthesis ◽  
Dependent Manner ◽  
New Genes ◽  
Colanic Acid ◽  
Operon Regulation ◽  
Operon Expression ◽  
High Level

ABSTRACT The gab operon (gabDTPC) in Escherichia coli functions in the conversion of γ-aminobutyrate to succinate. One component of gab operon regulation involves the RpoS sigma factor, which mediates activation at high cell density. Transposon mutagenesis was used to identify new genes that regulate gab operon expression in rich media. A Tn5tmp insertion in the hldD (formerly rfaD) gene increased gabT::lacZ expression 12-fold. The hldD gene product, an ADP-l-glycerol-d-mannoheptose-6-epimerase, catalyzes the conversion of ADP-d-glycerol-d-mannoheptose to ADP-l-glycerol-d-mannoheptose, a precursor for the synthesis of inner-core lipopolysaccharide (LPS). Defined mutations in hldE, required for heptose synthesis, and waaF, required for the addition of the second heptose to the inner core, also resulted in high-level gabT::lacZ expression. The hldD, hldE, and waaF mutants exhibited a mucoid colony phenotype due to production of a colanic acid capsule. However, in the hldD::cat background, the high-level expression of gabT::lacZ was independent of the regulatory components for colanic acid synthesis (rcsA, rcsB, and rcsC) and also independent of manC (cpsB), a structural gene for colanic acid synthesis. Activation of gabT::lacZ in the hldD::cat background was dependent on the RpoS sigma factor. The hldD::cat mutation resulted in a sixfold increase in the levels of a translational RpoS-LacZ fusion and had a marginal effect on a transcriptional fusion. This study reveals a stress-induced pathway, mediated by loss of the LPS inner core, that increases RpoS translation and gab operon expression in E. coli.

scholarly journals Role of Capsular Colanic Acid in Adhesion of Uropathogenic Escherichia coli

2003 ◽  
Vol 69 (8) ◽  
pp. 4474-4481 ◽  
Author(s):  
Andrea Hanna ◽  
Michael Berg ◽  
Valerie Stout ◽  
Anneta Razatos
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Bacterial Adhesion ◽  
Specific Binding ◽  
Binding Interactions ◽  
Colanic Acid ◽  
Mutant Strains ◽  
Tract Infections ◽  
Repulsive Forces

ABSTRACT Urinary tract infections are the most common urologic disease in the United States and one of the most common bacterial infections of any organ system. Biofilms persist in the urinary tract and on catheter surfaces because biofilm microorganisms are resistant to host defense mechanisms and antibiotic therapy. The first step in the establishment of biofilm infections is bacterial adhesion; preventing bacterial adhesion represents a promising method of controlling biofilms. Evidence suggests that capsular polysaccharides play a role in adhesion and pathogenicity. This study focuses on the role of physiochemical and specific binding interactions during adhesion of colanic acid exopolysaccharide mutant strains. Bacterial adhesion was evaluated for isogenic uropathogenic Escherichia coli strains that differed in colanic acid expression. The atomic force microscope (AFM) was used to directly measure the reversible physiochemical and specific binding interactions between bacterial strains and various substrates as bacteria initially approach the interface. AFM results indicate that electrostatic interactions were not solely responsible for the repulsive forces between the colanic acid mutant strains and hydrophilic substrates. Moreover, hydrophobic interactions were not found to play a significant role in adhesion of the colanic acid mutant strains. Adhesion was also evaluated by parallel-plate flow cell studies in comparison to AFM force measurements to demonstrate that prolonged incubation times alter bacterial adhesion. Results from this study demonstrate that the capsular polysaccharide colanic acid does not enhance bacterial adhesion but rather blocks the establishment of specific binding as well as time-dependent interactions between uropathogenic E. coli and inert substrates.

RcsC-mediated induction of colanic acid by secretion of streptokinase in Escherichia coli K-12

1996 ◽  
Vol 139 (2-3) ◽  
pp. 189-193
Author(s):  
H SI ◽  
C IL ◽  
S WEON ◽  
M SI
Keyword(s):  
Escherichia Coli ◽  
Colanic Acid ◽  
K 12

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.

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