Sequence and expression of the Escherichia coli K1 neuC gene product

Zapata, Gerardo; Crowley, J M; Vann, Willie F.

doi:10.1128/jb.174.1.315-319.1992

Cited by 31 publications

(32 citation statements)

References 29 publications

(9 reference statements)

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“…The mutation in nanA ensures that the NeuNAc added to the media was targeted for polymer synthesis and not a catabolic pathway. These observations are consistent with those of previous studies (29,41) and support the notion that NeuC is an essential enzyme in the biosynthesis of sialic acid. Zeitler et al previously showed that capsular polysaccharide production by a neuC insertion mutant was not complemented by ManNAc (43).…”

Section: Resultssupporting

confidence: 83%

“…These data are in good agreement with both the protein homologies and the indirect results reported by other investigators (29,41). Two radiolabeled reaction products that comigrated in paper chromatography with ManNAc and 2-acetamidoglucal resulted from the in vitro incubation of purified NeuC protein with UDP-[…”

Section: Discussionsupporting

confidence: 81%

“…NeuS is the polysialyltransferase that polymerizes activated CMP-NeuNAc to polysialic acid (31). NeuC (41) and NeuD (9) mutants are complemented by sialic acid and therefore appear to be involved in sialic acid biosynthesis. Reactions 1 and 2 summarize the postulated mechanism of sialic acid synthesis in E. coli K1: UDP-GlcNAc 3 ManNAc ϩ UDP…”

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confidence: 99%

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The NeuC Protein ofEscherichia coliK1 Is a UDPN-Acetylglucosamine 2-Epimerase

et al. 2004

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The K1 capsule is an essential virulence determinant of Escherichia coli strains that cause meningitis in neonates. Biosynthesis and transport of the capsule, an ␣-2,8-linked polymer of sialic acid, are encoded by the 17-kb kps gene cluster. We deleted neuC, a K1 gene implicated in sialic acid synthesis, from the chromosome of EV36, a K-12-K1 hybrid, by allelic exchange. Exogenously added sialic acid restored capsule expression to the deletion strain (⌬neuC), confirming that NeuC is necessary for sialic acid synthesis. The deduced amino acid sequence of NeuC showed similarities to those of UDP-N-acetylglucosamine (GlcNAc) 2-epimerases from both prokaryotes and eukaryotes. The NeuC homologue from serotype III Streptococcus agalactiae complements ⌬neuC. We cloned the neuC gene into an intein expression vector to facilitate purification. We demonstrated by paper chromatography that the purified neuC gene product catalyzed the formation of

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Section: Resultssupporting

confidence: 83%

Section: Discussionsupporting

confidence: 81%

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The NeuC Protein ofEscherichia coliK1 Is a UDPN-Acetylglucosamine 2-Epimerase

et al. 2004

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“…PCR was used to detect eight genes encoding virulence determinants usually associated with the E. coli strains responsible for extraintestinal infections: neuC (K1 capsule antigen), hly (alpha-hemolysin), papC (type P pili), sfa/foc (type S pili and type 1C fimbriae), fimH (type 1 pili), afa (afimbrial adhesin), iucC (aerobactin), and ibeA (IbeA protein) (2,14,18,34,35). Each VF gene was amplified with the primers described in Table 1 in a total volume of 25 l containing 1ϫ PCR buffer, 0.1 mM (each) deoxyribonucleoside triphosphate, 0.5 M (each) primer, 0.5 U of Taq polymerase, and 25 ng of DNA.…”

Section: Methodsmentioning

confidence: 99%

Escherichia coli Strains from Pregnant Women and Neonates: Intraspecies Genetic Distribution and Prevalence of Virulence Factors

et al. 2003

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To determine the extent to which the vagina, endocervix, and amniotic fluid screen the Escherichia coli strains responsible for neonatal infections, we studied the genetic relationships among 105 E. coli strains isolated from all of the ecosystems involved in this infectious process. Twenty-four strains were isolated from the intestinal flora, and 25 strains were isolated from the vaginas of pregnant women. Twenty-seven strains were isolated from the amniotic fluid, blood, and cerebrospinal fluid (CSF) of infected neonates. The intraspecies genetic characteristics of all of the isolates were determined by random amplified polymorphic DNA (RAPD) analysis, PCR ECOR (E. coli reference) grouping, and PCR virulence genotyping. A correlation was found between the intraspecies distributions of the strains in the A, B1, B2, and D ECOR groups and in the two major RAPD groups (I and II). Nevertheless, the distribution of the E. coli strains in the RAPD groups according to their anatomical origins was more significant than their distribution in the ECOR groups. This may be explained by the existence of an E. coli subpopulation, defined by the RAPD I group, within the ECOR B2 group. This RAPD I group presents a major risk for neonates: 75% of the strains isolated from patients with meningitis and 100% of the strains isolated from patients with bacteremia were in this group. The vagina and the amniotic fluid are two barriers that favor colonization by highly infectious strains. Indeed, only 17% of fecal strains belonged to the RAPD I group, whereas 52% of vaginal strains and 67% of amniotic fluid strains belonged to this subpopulation. The ibeA and iucC genes were significantly associated with CSF strains, whereas the hly and sfa/foc genes were more frequent in blood strains. These findings could serve as a basis for developing tools to recognize vaginal strains, which present a high risk for neonates, for use in prophylaxis programs.

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“…Virulence factor genes were amplified with the primers described elsewhere [14,[18][19][20][21], in a total volume of 50 L containing 25 L of KapaTaq 2x Ready Mix (KAPA Biosystems, USA), 20 pmol concentrations of each primer except hly (30 pmol), and 5 L of DNA template [14]. The reaction conditions were as follows [18]: initial denaturation at 94°C for 5 min followed by 25 cycles of denaturation at 94°C for 30 s, annealing at 63°C for 30 s, and extension at 68°C for 3 min, followed by a final 10-min extension period at 72°C.…”

Section: Genotypic Virulence Characterization Of the Isolatesmentioning

confidence: 99%

Phylogenetic Grouping and Virulence Characterization of ESBL-Producing and Non-Producing Vaginal Escherichia Coli

Al-Mayahie¹

2014

AJBLS

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Abstract:The initial colonization of the vaginal mucosa with Escherichia coli is considered as a critical step toward urinary tract and neonatal infections. This study was conducted to characterize ESBL-producing (n=40) vaginal E. coli isolates from pregnant and non-pregnant women. These isolates were compared with corresponding ESBL-non-producing E. coli isolates (n=21). Both groups were investigated using PCR-based protocols for their phylogenetic origin and virulence genotype. High numbers of ESBL producers and non-producers were from group B2 (47.5% vs. 42.8%, respectively). None of ESBL nonproducers clustered in group D, whereas significant numbers (P ≤ 0.05) of them belonged to group B1 (33.3%) in comparison with 20.0% and 7.5% of ESBL producers, respectively. Significant differences in the prevalence of this study included virulence factors were not observed between these two groups. In both high rates of multiple virulence factors possession were demonstrated among isolates belonged to groups B2 and D. Comparison of CTX-M-producers with non-CTX-M-ESBLproducers and ESBL-non-producers revealed no significant differences among these three groups. In total, 60.8%, 17.3%, 17.3% and 4.3% of multidrug resistant (MDR) isolates clustered in groups B2, D, A and B1, respectively. All MDR-ESBL-non producers (100%) belonged to phylogroup B2 compared with 50% of MDR ESBL-producers and their virulence was much more higher. This study indicates that significant differences are not present between ESBL-producing and non-producing vaginal E. coli for both phylogenetic group distribution and virulence genes possession. Also, ESBL-producing vaginal E. coli, especially CTX-M producers, tend to be more dominant among the highly virulent phylogroup B2 and to a lesser extent group D. These data reveal the importance of vaginal colonization by these highly virulent, MDR, ESBL-producing E. coli as a source of extraintestinal E. coli infections.

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Sequence and expression of the Escherichia coli K1 neuC gene product

Cited by 31 publications

References 29 publications

The NeuC Protein ofEscherichia coliK1 Is a UDPN-Acetylglucosamine 2-Epimerase

The NeuC Protein ofEscherichia coliK1 Is a UDPN-Acetylglucosamine 2-Epimerase

Escherichia coli Strains from Pregnant Women and Neonates: Intraspecies Genetic Distribution and Prevalence of Virulence Factors

Phylogenetic Grouping and Virulence Characterization of ESBL-Producing and Non-Producing Vaginal Escherichia Coli

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