IS2-mediated overexpression of kfoC in E. coli K4 increases chondroitin-like capsular polysaccharide production

2014 ◽  
Vol 98 (9) ◽  
pp. 3955-3964 ◽  
Author(s):  
D. Cimini ◽  
S. Fantaccione ◽  
F. Volpe ◽  
M. De Rosa ◽  
O. F. Restaino ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
E Coli ◽  
Polysaccharide Production

scholarly journals Kinetics of Targeted Phage Rescue in a Mouse Model of SystemicEscherichia coliK1

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
György Schneider ◽  
Nikolett Szentes ◽  
Marianna Horváth ◽  
Ágnes Dorn ◽  
Alysia Cox ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Protective Efficacy ◽  
Lytic Bacteriophage ◽  
E Coli ◽  
Causative Agents ◽  
High Level ◽  
Systemic Infections ◽  
Kinetics Of

Escherichia (E.) coliK1 strains remain common causative agents of neonatal sepsis and meningitis. We have isolated a lytic bacteriophage (ΦIK1) againstE. colistrain IHE3034 and tested its specificityin vitro, as well as distribution and protective efficacyin vivo. The phage was shown to be specific to the K1 capsular polysaccharide. In the lethal murine model, a high level of protection was afforded by the phage with strict kinetics. A single dose of 1 x 108phage particles administered 10 and 60 minutes following the bacterial challenge elicited 100 % and 95 % survival, respectively. No mice could be rescued if phage administration occurred 3 hours postinfection. Tissue distribution surveys in the surviving mice revealed that the spleen was the primary organ in which accumulation of active ΦIK1 phages could be detected two weeks after phage administration. These results suggest that bacteriophages have potential as therapeutic agents in the control of systemic infections.

S5.9 Heparin-like compounds prepared by chemical modification of capsular polysaccharide from E. coli K5

1993 ◽  
Vol 10 (4) ◽  
pp. 252-253
Author(s):  
N. Razi ◽  
E. Feyzi ◽  
I. Bj�rk ◽  
U. Lindahl ◽  
P. Oreste ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Capsular Polysaccharide ◽  
E Coli

Serological and conformational properties of E. coli K92 capsular polysaccharide and its N-propionylated derivative both illustrate that induced antibody does not recognize extended epitopes of polysialic acid: Implications for a comprehensive conjugate vaccine against groups B and C N. meningitidis

2002 ◽  
Vol 80 (8) ◽  
pp. 1055-1063 ◽  
Author(s):  
Robert A Pon ◽  
Nam Huan Khieu ◽  
Qing-Ling Yang ◽  
Jean-Robert Brisson ◽  
Harold J Jennings
Keyword(s):  
Molecular Dynamics ◽  
Immune Response ◽  
Conjugate Vaccine ◽  
Capsular Polysaccharide ◽  
Competitive Inhibition ◽  
Polysialic Acid ◽  
E Coli ◽  
Protective Epitope ◽  
Conformational Properties ◽  
Group B

The capsular polysaccharide of E. coli K92 (K92P) contains elements in common with the capsular polysaccharides of both groups B and C N. meningitidis, and may therefore form the basis of a bivalent vaccine. In an attempt to augment the cross-protective immune response to group B meningococci, the N-acetyl groups of the K92P were replaced by N-propionyl groups (NPrK92P) and conjugated to protein. This strategy had previously been applied with success to the poorly immunogenic capsular polysaccharide of group B meningococcus (GBMP), and the bactericidal epitope was found to be exclusively mimicked by extended helical segments of the NPrGBMP. The NPrK92P-conjugate, in relation to a K92P-conjugate, failed to enhance the response to GBMP but did generate a measurable response to NPrGBMP, but only at the expense of a greatly reduced GCMP response. Despite the presence of an immune response to NPrGBMP, the anti-NPrK92 serum was not bactericidal. Competitive inhibition studies with NPrGBMP oligosaccharides suggested the NPrK92 antibodies could not cross-react with the protective epitope on group B meningococci, as defined by extended helical segments of the NPrGBMP, but only recognized short non-bactericidal NPrGBMP epitopes. This hypothesis was supported from the conformational and molecular dynamics studies of the K92P, which demonstrated a lack of extended conformations that resemble the GBMP extended epitope. Indeed, the conformational properties of the K92P more closely resembled those of the GCMP, thereby explaining the observed moderate cross-protection of the K92P antiserum towards group C meningococci. Thus, on the basis of these results, it can be concluded that K92P, regardless of N-propionyl modification, will not serve as an effective single vaccine component against both groups B and C meningococci.Key words: conjugate vaccine, Neisseria meningitidis, polysialic acid, NMR, molecular dynamics.

scholarly journals Overexpression of UDP-glucose dehydrogenase in Escherichia coli results in decreased biosynthesis of K5 polysaccharide

2003 ◽  
Vol 374 (3) ◽  
pp. 767-772 ◽  
Author(s):  
Elisabet ROMAN ◽  
Ian ROBERTS ◽  
Kerstin LIDHOLT ◽  
Marion KUSCHE-GULLBERG
Keyword(s):  
Escherichia Coli ◽  
Capsular Polysaccharide ◽  
Glucose Dehydrogenase ◽  
Fold Increase ◽  
Extra Copy ◽  
Polysaccharide Biosynthesis ◽  
Polysaccharide Production ◽  
Significant Difference ◽  
K5 Polysaccharide

The Escherichia coli K5 capsular polysaccharide (glycosaminoglycan) chains are composed of the repeated disaccharide structure: -GlcAβ1,4-GlcNAcα1,4-(where GlcA is glucuronic acid and GlcNAc is N-acetyl-d-glucosamine). The GlcA, present in most glycosaminoglycans, is donated from UDP-GlcA, which, in turn, is generated from UDP-glucose by the enzyme UDP-glucose dehydrogenase (UDPGDH). The formation of UDP-GlcA is critical for the biosynthesis of glycosaminoglycans. To investigate the role of UDPGDH in glycosaminoglycan biosynthesis, we used K5 polysaccharide biosynthesis as a model. E. coli was transformed with the complete gene cluster for K5 polysaccharide production. Additional transformation with an extra copy of UDPGDH resulted in an approx. 15-fold increase in the in vitro UDPGDH enzyme activity compared with the strain lacking extra UDPGDH. UDP-GlcA levels were increased 3-fold in overexpressing strains. However, metabolic labelling with [14C]glucose showed, unexpectedly, that overexpression of UDPGDH lead to decreased formation of K5 polysaccharide. No significant difference in the K5 polysaccharide chain length was observed between control and overexpressing strains, indicating that the decrease in K5-polysaccharide production most probably was due to synthesis of fewer chains. Our results suggest that K5-polysaccharide biosynthesis is strictly regulated such that increasing the amount of available UDP-GlcA results in diminished K5-polysaccharide production.

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