Structure, Function, and Regulation of the Plasmid-Encoded Hemolysin Determinant of Escherichia Coli

Goebel, Werner; Hacker, Jörg; Knapp, S.; Then, I.; Wagner, Wilma; Juárez, Antonio

doi:10.1007/978-1-4613-2447-8_55

Cited by 27 publications

(41 citation statements)

References 14 publications

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“…60 kDa) product confers this phenotype. Earlier studies have shown that this breakdown product of HlyA recognized by HlyA antibodies may have haemolytic activity (Noegel et al, 1979 ;Goebel & Hedgpeth, 1982 ;Nicaud et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

Expression of cytotoxicity by potential pathogens in the standard Escherichia coli collection of reference (ECOR) strains The GenBank accession numbers for the sequences reported in this paper are AF159702 and AF160993–161002.

1999

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The standard Escherichia coli collection of reference (ECOR) strains was examined for ability to exert cytotoxicity towards mammalian cells. A group of strains with functional haemolysin expression caused strong cytotoxicity and detachment in J774 macrophage cells as measured by lactate dehydrogenase release and as observed under a microscope. The expression of haemolysin was monitored by using antisera recognizing the E. coli α-haemolysin, the HlyA protein, and by quantitative haemolysis assays. The presence of the hlyA gene, which may be part of a pathogenicity island, was also confirmed. These analyses revealed that different ECOR strains express quantitatively different levels of haemolysin. One putative enteroaggregative E. coli (EAEC) strain was also found in the ECOR collection. The EAEC strain was characterized by the clump formation assay, PCR amplification of the EAEC DNA probe sequence and confirmative sequence analysis of the amplified fragment. The EAEC heat-stable enterotoxin 1 gene, astA, was found in 14 % (10/72) of the ECOR strains and a consensus sequence for astA was proposed by comparing these sequences with those from pathogens. The astA gene appeared to be plasmid-located. Based on evidence from the work of other laboratories and from the present findings, it is concluded that the ECOR collection contains strains that may represent pathogenic E. coli. It is noted that caution is necessary when handling or disposing of those potentially pathogenic ECOR strains.

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Section: Discussionmentioning

confidence: 99%

Expression of cytotoxicity by potential pathogens in the standard Escherichia coli collection of reference (ECOR) strains The GenBank accession numbers for the sequences reported in this paper are AF159702 and AF160993–161002.

1999

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“…Furthermore, these toxins are synthesized as inactive protoxins, requiring one or two posttranslational acylations in order to exert their full cytotoxic activity once they are translocated and folded correctly in the extracellular space. The essential acylation of ε-amino groups of internal lysine residues of the protoxin is catalyzed by coexpressed RtxC acyltransferases (192,215,216). Three different RtxC lysine acyltransferases, HlyC from E. coli, CyaC from Bordetella pertussis, and LtxC from Aggregatibacter (Formerly Actinobacillus) actinomycetemcomitans have been characterized.…”

Section: Rtxc Acyltransferases That Activate Rtx Leukotoxinsmentioning

confidence: 99%

Acyltransferases in Bacteria

Röttig

Steinbüchel

2013

Microbiol Mol Biol Rev

144

141

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SUMMARY Long-chain-length hydrophobic acyl residues play a vital role in a multitude of essential biological structures and processes. They build the inner hydrophobic layers of biological membranes, are converted to intracellular storage compounds, and are used to modify protein properties or function as membrane anchors, to name only a few functions. Acyl thioesters are transferred by acyltransferases or transacylases to a variety of different substrates or are polymerized to lipophilic storage compounds. Lipases represent another important enzyme class dealing with fatty acyl chains; however, they cannot be regarded as acyltransferases in the strict sense. This review provides a detailed survey of the wide spectrum of bacterial acyltransferases and compares different enzyme families in regard to their catalytic mechanisms. On the basis of their studied or assumed mechanisms, most of the acyl-transferring enzymes can be divided into two groups. The majority of enzymes discussed in this review employ a conserved acyltransferase motif with an invariant histidine residue, followed by an acidic amino acid residue, and their catalytic mechanism is characterized by a noncovalent transition state. In contrast to that, lipases rely on completely different mechanism which employs a catalytic triad and functions via the formation of covalent intermediates. This is, for example, similar to the mechanism which has been suggested for polyester synthases. Consequently, although the presented enzyme types neither share homology nor have a common three-dimensional structure, and although they deal with greatly varying molecule structures, this variety is not reflected in their mechanisms, all of which rely on a catalytically active histidine residue.

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“…The recombinant hemolysin (h/y+) plasmids used (pANN202-312, pANN5211-06; pANN5311-018, pANN5411-075) contain BamHI-Sall fragments carrying the genes hlyA, hlyB and hlyD of various chromosomal (strains 536-06, 764-018, 341-075 31 ) and plasmid-(pHiy152 30 ) encoded h/y determinants cloned into pANN202. pANN202 is pACYC184 bearing hlyC ot the plasmid pHiy152 (Table 1 and Fig.…”

Section: Recombinant Dnasmentioning

confidence: 99%

Influence of cloned Escherichia coli hemolysin genes, S-fimbriae and serum resistance on pathogenicity in different animal models

Hacker

Hof

Emödy

et al. 1986

Microbial Pathogenesis

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of cloned hemolysin genes, S-fimbriae and serum resistance on pathogenicity in different animal models. Microbial Pathogenesis 1986; 1: 000-000.The virulence of the uropathogenic E. coli strain 536 (06: K 1 5: H31) which produces the S-fimbrial adhesin (Sfa•), is serum-resistant (Sre+) and hemolytic (Hiy+) and its derivatives were assessed in five different animal models. Cloned hemolysin (h/y) determinants from the Chromosomes of 06,018 and 075 E. colistrains and from the plasmid pHiy152 were introduced into the spontaneaus Sfa-, Sre-, Hly-mutant 536-21 and its Sfa+, Sre+, Hly-variant 536-31. As already demonstrated for the 536-21 strains {lnfect. Immun. 42: 57-63) the 018-hly determinant but not the plasmid-encoded hly determinant of pHiy 1 52 transformed into 536-31 contribute to lethality in a mouse peritonitis modal. Similar results were obtained with both Hlyhost strains and their Hly+ transformants in a chicken embryo test and in a mouse nephropathogenicity assay in which the renal bacterial counts were measured 1 5 min to 8 hours after i.v. infection. S-fimbriae and serum resistance had only a marginal influence in these three in vivo systems. ln centrast all three factors, S-fimbriae, serum resistance and hemolysin, were necessary for full virulence in a respiratory mouse infection assay. ln a subcutaneously-induced sepsis model in the mouse restoration of S-fimbriae and serum resistance and separately chromosomally-encoded hemolysis increased virulence to a Ievel comparable to that of the parental 536 strain.Key words: E. coli hemolysin. S-fimbriae; serum resistance. E. coli virulence; animal models; gene cloning. lntroductionEscherichia coli strains are responsible for most urinary tract infections (UTI). Certain E. coli clones cause neonatal sepsis and meningitis. 1 -3 Many cell components such as adhesins, serum resistance factors, cytolysins and others have been shown to be associated with extraintestinal virulence in E. coli. 4 Adhesion factors which recognize galactosyl-galactose receptors (P fimbriae 2 · 5 ) are common among UTI strains. S-fimbriae specifically bind to sialic acid containing structures are frequently associated with isolates from cases of newborn meningitis.3·6 The genetic determinants for S~fimbrial adhesins (sfa) cover a stretch of

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Structure, Function, and Regulation of the Plasmid-Encoded Hemolysin Determinant of Escherichia Coli

Cited by 27 publications

References 14 publications

Expression of cytotoxicity by potential pathogens in the standard Escherichia coli collection of reference (ECOR) strains The GenBank accession numbers for the sequences reported in this paper are AF159702 and AF160993–161002.

Expression of cytotoxicity by potential pathogens in the standard Escherichia coli collection of reference (ECOR) strains The GenBank accession numbers for the sequences reported in this paper are AF159702 and AF160993–161002.

Acyltransferases in Bacteria

Influence of cloned Escherichia coli hemolysin genes, S-fimbriae and serum resistance on pathogenicity in different animal models

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