@article{MorschhaeuserVetterKorhonenetal.1993, author = {Morschh{\"a}user, Joachim and Vetter, Viktoria and Korhonen, Timo and Uhlin, Bernt Eric and Hacker, J{\"o}rg}, title = {Regulation and binding properties of S fimbriae cloned from E. coli strains causing urinary tract infection and meningitis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86140}, year = {1993}, abstract = {S fimbriae are able to recognize receptor molecules containing sialic acid and are produced by pathogenic E. coli strains causing urinary tract infection and menigitis. In order to characterize the corresponding genetic determinant, termed S fimbrial adhesin ( sfa) gene duster, we have cloned the S-specific genes from a urinary pathogen and from a meningitis isolate. Nine genes are involved in the production of S fimbriae, two of these, sfaB and sfaC code for regulatory proteins being necessary for the expression of S fimbriae. Two promoters, PB and Pc, are located in front of these genes. Transcription of the sfa determinant is influenced by activation of the promotersvia SfaB and SfaC, the action of the H-NS protein and an RNaseE-specific mRNA processing. In addition, a third promoter, P A• located in front of the major subunit gene sfaA, can be activated under special circumstances. Four genes of the sfa determinant code for the subunit-specific proteins, SfaA (16 kda), SfaG (17 kda), SfaS (14 kda) and SfaH (29 kda). It was demonstrated that the protein SfaA is the major subunit protein while SfaS is identical to the sialic-acid-specific adhesin of S fimbriae. The introduction of specific mutations into sfaS revealed that a region of six amino acids of the adhesin which includes two lysine and one arginine residues is involved in the receptor specific interaction of S fimbriae. Additionally, it has been shown that SfaS is necessary for the induction of fimbriation while SfaH plays a role in the stringency of binding of S fimbriae to erythrocytes.}, subject = {Escherichia coli}, language = {en} } @article{TschaepeBenderOttetal.1992, author = {Tsch{\"a}pe, Helmut and Bender, Larisa and Ott, Manfred and Wittig, Walter and Hacker, J{\"o}rg}, title = {Restriction fragments length polymorphism and virulence pattern of the veterinary pathogen Escherichia coli O139:K82:H1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86131}, year = {1992}, abstract = {Escherichia coli 0139: K82: H1 strains originating from outbreaks and single cases of oedema disease in pigs were characterized by their genomic restriction fragment length polymorphism (RFLP), their virulence pattern, and by the occurrence as well as the genomic distribution of the determinants for hemolysin (hly) and verotoxins (shiga-like toxins; sltI, sltII). Whereas the RFLPs revealed considerable variation among the E. coli 0139: K82: H1 isolates depending the origin and epidemic source of the strains, the virulence gene slt II was found to be present in nearly all strains in a particular chromosomal region. Similar to RFLPs, the plasmid profiles are useful for epidemiological analysis.}, subject = {Escherichia coli}, language = {en} } @article{HackerOttBlumetal.1992, author = {Hacker, J{\"o}rg and Ott, Manfred and Blum, Gabriele and Marre, Reinhard and Heesemann, J{\"u}rgen and Tsch{\"a}pe, Helmut and Goebel, Werner}, title = {Genetics of Escherichia coli uropathogenicity: Analysis of the O6:K15:H31 isolate 536}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71578}, year = {1992}, abstract = {E. coli strain 536 (06: K15: H31) isolated from a case of acute pyelonephritis, expresses S-fimbrial adhesins, P-related fimbriae, common type I fimbriae, and hemolysins. The respective chromosomally encoded determinants were cloned by constructing a genomic library of this strain. Furthermore, the strain produces the iron uptake substance, enterocheline, damages HeLa cells, and behaves in a serum-resistant mode. Genetic analysis of spontaneously arising non-hemolytic variants revealed that some of the virulence genes were physically linked to large unstable DNA regions, termed "pathogenicity islands", which were mapped in the respective positions on the E. coli K-12linkage map. By comparing the wild type strain and mutants in in vitro and in vivo assays, virulence features have been evaluated. In addition, a regulatory cross talk between adhesin determinants was found for the wild-type isolate. This particular mode of virulence regulation is missing in the mutant strain.}, subject = {Escherichia coli}, language = {en} } @article{OttHacker1991, author = {Ott, M. and Hacker, J{\"o}rg}, title = {Analysis of the variability of S fimbriae expression in an Escherichia coli pathogen.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59695}, year = {1991}, abstract = {The uropathogenic Escherichia coli wiJd..:type strain 536 produces S-fimbriae, P-related fimbriae and type I fimbriae. Using immuno-colony dot and ELISA techniques, variants were detected showing an increased degree of S-fimbrial production. It was demonstrated by itrtmunofluorescence microscopy that in noimal (wild-type) and hyperS- fimbriated E. coli populaiions non-fimbriated cells also · exist, and that the percentage of Sfinibrlated and non-fimbriated bacteria was roughly identica1 in either population. Hyper-Sfimbriated variants could be stably maintained. The transition from wild-type to hyper-S-fimbriation, which occurs spontaneously, is markedly higher than vice versa. Southern blot analysis of the S fimbrial adhesin (sfa) determinants of normal and hyper-fimbriated strains revealed no marked difference in the gene structure.}, subject = {Infektionsbiologie}, language = {en} } @article{VanDieKramerHackeretal.1991, author = {Van Die, I. and Kramer, C. and Hacker, J{\"o}rg and Bergmans, H. and Jongen, W. and Hoekstra, W.}, title = {Nucleotide sequence of the genes coding for minor fimbrial subunits of the F1C fimbriae of Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40353}, year = {1991}, abstract = {F 1 C fimbriae allow uropathogenic Escherichia coli to adhere to specific epithelial surfaces. This adhesive property is probably due to the presence of minor fimbrial components in F1C fimbriae. The foe gene cluster encoding F1C fimbriae has been cloned, as described previously. Here we present the nucleotide sequence (2081 bp) coding for the F 1 C minor fimbria I subunits. The structural genes code for polypeptides of 175 (FocF), 166 (FocG), and 300 (FocH) amino acids. The deduced amino acids of the F 1 C minor subunits were compared with the reported sequences of the minor subunits of other types of fimbriae. The data show that the Foc minor subunits are highly homologous to the corresponding Sfa proteins, whereas homology to the minor subunits of type 1 and P fimbriae is much lower.}, language = {en} } @article{SchrotenWolskePlogmannetal.1991, author = {Schroten, Horst and Wolske, Anja and Plogmann, Ricarda and Hanisch, Franz-Georg and Hacker, J{\"o}rg and Uhlenbr{\"u}ck, Gerhard and Wahn, Volker}, title = {Binding of cloned S-fimbriated E. coli to human buccal epithelial cells-different inhibition of binding by neonatal saliva and adult saliva.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86291}, year = {1991}, abstract = {Investigations were carried out on the adhesion of cloned S-fimbriated E. coli, labelled with fluoresceinisothiocyanate (FITC) to human buccal epithelial cells. Fluorescence microscopic analysis revealed binding of bacteria to 75-95\% of epithelial cells. Inhibition experiments with fetuin, a 1-acid glycoprotein and N-acetyl neuraminic acid confirmed the specificity of bacterial binding to sialoglycoproteins. Further studies using saliva as an inhibitor resulted in a 4-5 times stronger binding inhibition by newborn saliva in comparison to adult saliva coinciding with a 4-5 times higher content of total N-acetyl neuraminic acid in samples of newborn saliva. In Western blot analysis sialoglycoprotein bands with a molecular weight >200 kD reacting with wheat germ agglutinin (WGA), were only identified in samples of newborn saliva. These bands are classified as mucins on account of molecular weight and staining. These data suggest that saliva mucins could represent a major defense mechanism against bacterial infections at a stage of ontogeny where the secretory IgAsystem is not yet developed.}, subject = {Escherichia coli}, language = {en} } @article{ParkkinenHackerKorhonen1991, author = {Parkkinen, Jaakko and Hacker, J{\"o}rg and Korhonen, Timo K.}, title = {Enhancement of tissue plasminogen activator-catalyzed plasminogen activation by Escherichia coli S fimbriae associated with neonatal septicaemia and meningitis.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71566}, year = {1991}, abstract = {The effect of Escherichia coli strains isolated from blood and cerebrospinal fluid of septic infants on plasminogen activation was studied. These strains typically carry a filamentous surface protein, S fimbria, that has formerly been shown to bind to endothelial cells and interact with plasminogen. The bacteria effectively promoted plasminogen activation by tissue plasminogen activator (t-PA) which was inhibited by e-aminocaproic acid. A recombinant strain expressing S fimbriae accelerated t-PAcatalyzed plasminogen activation to a similar extent as did the wild-type strains whereas the nonfimbriate recipient strain had no effect. After incubation with t-PA and plasminogen, the S-fimbriate strain displayed bacterium-bound plasmin activity whereas the nonfimbriate strain did not. Bacterium-associated plasmin generation was also observed with a strain expressing mutagenized S fimbriae that Iack the cell-binding subunit SfaS but not with a strain lacking the major subunit SfaA. Both t-PA and plasminogen bound to purified S fimbriae in a lysine-dependent manner and purified S fimbriae accelerated t-PA-catalyzed plasminogen activation. The results indicate that E. coli S fimbriae form a complex with t-PA and plasminogen which enhances the rate of plasminogen activation and generates bacterium-bound plasmin. This may promote bacterial invasion and persistence in tissues and contribute to the systemic activation of fibrinolysis in septicaemia.}, subject = {Escherichia coli}, language = {en} } @article{SchmollMorschhaeuserOttetal.1990, author = {Schmoll, T. and Morschh{\"a}user, J. and Ott, M. and Ludwig, B. and Van Die, I. and Hacker, J{\"o}rg}, title = {Complete genetic organization and functional aspects of the Escherichia coli S fimbrial adhesin determinant: nucleotide sequence of the genes sfaB, C, D, E, F.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59661}, year = {1990}, abstract = {The S fimbrial adhesin (sfa) determinant of E. co/i comprises nine genes situated on a stretch of 7.9 kilobases (kb) DNA. Here the nucleotide sequence of the genes sfa B and sfaC situated proximal to the main structural gene sfaA is described. Sfa-LacZ fusions show that the two genes are transcribed in opposite directions. The isolation of mutants in the proximal region of the sfa gene cluster, the construction of sfa-phoA gene fusions and subsequent transcomplementation sturlies indicated that the genes sfaB and sfaC play a role in regulation of the sfa determinant. ln addition the nucleotide sequence of the genes sfa D, sfa E and sfa F situated between the genes sfaA and sfaG responsible for S subunit proteins, were determined. lt is suggested that these genes are involved in transport and assembly of fimbrial subunits. Thus the entire genetic organization of the sfa determinant is presented and compared with the gene clusters coding for P fimbriae (pap), F1 C fimbriae (foc) and type I fimbriae ( fim). The evolutionary relationship of fimbrial adhesin determinants is discussed.}, subject = {Infektionsbiologie}, language = {en} } @article{HackerGadebergOrskov1989, author = {Hacker, J{\"o}rg and Gadeberg, Ole V. and Orskov, Ida}, title = {Role of alpha-Hemolysin for the in vitro Phagocytosis and intracellular killing of Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-73019}, year = {1989}, abstract = {The_role of a-hemolysin for the elimination of Eschericbia coli by phagocyres in vitro was investigated using sets of isogenic strains which included wild-type a -hemolyric srrains, derived strains with a reduced production of a-hemolysin and derived nonhemolytic strains. Phagocyrosis and intracellular killing of the bacteria by human blood granulocytes or monocytes were measured using growth inhibition rechniques. a-hemolytic strains were phagocytosed and killed ro a Jesser extent than isogenic strains with a reduced production of o:hemoJysin and isogenic nonhemolytic strains. The results obrained with granulocyres were similar to rhose obtained with monocyres although the elimination of bacteria by monocytes was less than that by granulocytes. These resulcs strongJy suggest that production of ahemolysin is a means by which E. coli counteracrs the activity of phagocytes by injuring these cells with the toxin.}, subject = {Escherichia coli}, language = {en} } @article{KrallmannWenzelOttHackeretal.1989, author = {Krallmann-Wenzel, U. and Ott, M. and Hacker, J{\"o}rg and Schmidt, G}, title = {Chromosomal mapping of genes encoding mannose-sensitive (type I) and mannose-resistant F8(P) fimbriae of Escherichia coli O18:K5:H5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59545}, year = {1989}, abstract = {DNA hybridization experiments demonstrated that the gene clusters encoding the F8 fimbriae (fei) as well as the type I fimbriae (pi/) exist in a single copy on the chromosome of E. coli 018:K5 strain 2980. In conjugation experiments with appropriate donors, the chromosomal site of these gene clusters was determined. The pil genes were mapped close to the gene clusters thr and Jeu controlling the biosynthesis of threonine and leucine, respectively. The fei genes were found to be located close to the galactose operon (gal) between the position 17 and 21 of the E. coli chromosomallinkage map.}, subject = {Infektionsbiologie}, language = {en} }