@article{WintermeyerRdestLudwigetal.1991,
  author    = {Wintermeyer, E. and Rdest, U. and Ludwig, B. and Debes, A. and Hacker, J{\"o}rg},
  title     = {Characterization of legiolysin (lly); responsible for hemolytic activity, colour production and fluorescence of Legionella pneumophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59706},
  year      = {1991},
  abstract  = {No abstract available},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{OttMessnerHeesemannetal.1991,
  author    = {Ott, M. and Messner, P. and Heesemann, J. and Marre, R. and Hacker, J{\"o}rg},
  title     = {Temperature dependent expression of flagella in Legionella},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59755},
  year      = {1991},
  abstract  = {Legionel/a pneumophila, the causative agent of Legionnaires' disease, was analysed by electron microscopy for production of surface structures. Crystalline surface (S-) layers and fimbriae were not detected, but monotrichous flagellation was seen. Polyclonal antibodies specific for the 47 kDa ftagellin subunit of L. pneumophila Philadelphia I were used in Western blots to confirm the presence of flagella subunits in various L. pneumophila strains tested, but the antiserumalso reacted with flagellin subunits of L. micdlulei, L. hackelia (serogroup (SG) l and SG21 and L./ongbetichae (SG2). Flagellation of Legionellae was shown to be temperature regulated. When the growth temperature of virulent and avirulent variants of strain L. pneumophila Philadelphia I was shifted from 30 oc to either 37 or 41 oc, a decrease in the percentage offtagellated bacteria within the populationwas observed.},
  subject      = {Infektionsbiologie},
  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{OttBenderMarreetal.1991,
  author    = {Ott, M. and Bender, L. and Marre, R. and Hacker, J{\"o}rg},
  title     = {Pulsed field electrophoresis of genomic restriction fragments for the detection of nosocomial Legionella pneumophila in hospital water supplies},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59672},
  year      = {1991},
  abstract  = {Ten Legionella pneumophUa strains isolated from dift'erent sources were analyzed according to their restriction fragment patterils obtained by cle~vage of gen.omic DNA With Notl and Sftl and separation by pulsed field electrophoresis. Three L. pneumophila isolate~ from a nosocomial outbreak in L{\"u}~k (Germany) and three other L. prreumophilll stralns independently isolated from a water tap located in the care unit where tbe patients were bospitalized 'xhibited identical restricti9n fragment profiles. Therefore, we concluded that these environment81 spee~ens were the source of the Legionnatres dlsease. Anotber two isolates from patients and two strains from the environment, all unrelated to the outJlreak described, sbowed different cleavage patterns.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{OttBenderChirinosetal.1991,
  author    = {Ott, M. and Bender, L. and Chirinos, E. and Ehret, W. and Hacker, J{\"o}rg},
  title     = {Phenotype versus genotype of the 19 kd peptido-glycan associated protein of Legionella (PplA) among Legionellae and other gram-negative bacteria},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59768},
  year      = {1991},
  abstract  = {The protein PpiA (19 kD) cloned from a genomic library of Legionella pneumophila, Philadelphia 1, represents a peptido-glycan associated outer membrane protein in recombinant E. coli K-12 and L. pneumophila. lt exhibits distinct sequence homology to Iipoproteins of Haemophilus influenzae and E. coli. A ppiA specific DNA probe generated by PCR was used in Southern hybridizations of chromosomal DNA of Legionella strains and other Gram-negative pathogens. Under conditions of high stringency, hybridization could only be observed in L. pneumophila isolates, but alt other Legionella strains tested displayed hybridization under lower stringency. No signals appeared after hybridization of chromosomal DNA from a variety of other bacteria. Using anti-PpiA monospecific polyclonal antibodies in Western blots, it was demonstrated that PpiA related proteins of nearly the same size are found in all L. pneumophila isolates and in a variety of, but not alt, the Legionella species analysed here.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{OttBenderBlumetal.1991,
  author    = {Ott, M. and Bender, L. and Blum, G. and Schmittroth, M. and Achtmann, M. and Tsch{\"a}pe, H. and Hacker, J{\"o}rg},
  title     = {Virulence patterns and long range mapping of extraintestinal Escherichia coli K1, K5 and K100 isolates: Use of pulse field gel electrophoresis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59738},
  year      = {1991},
  abstract  = {A total of 127 extraintestinal Escherichia coli strains of the capsule serotypes Kl, KS, and KlOO from human and animal sources were analyzed for DNA sequences specific for the genes for various adhesins (P fimbriae fpap] and P-related sequences fprs], S fimbriae [s/a)/FlC fimbriae [foc], and type I fimbriae lfim]), aerobactin (aer), and hemolysin (hly). The expression of corresponding virulence factors was also tested. Twenty-four selected strains were analyzed by long-range DNA mapping to evaluate their genetic relationships. DNA sequences for the adhesins were often found in strains not expressing them, while strains with hemolysin and aerobactin genes usually did express them. Different isolates of the same serotype orten expressed different virulence patterns. The use of virulence-associated gene probes for Southern hybridization with genomic DNA fragments separated by pulsed-field gel electrophoresis revealed that a highly heterogeneous restriction fragment length and hybridization pattern existed even within strains of the same serotype. Long-range DNA mapping is therefore useful for the evaluation of genetic relatedness among individual isolates and facilitates the performance of .precise molecular epidemiology.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{LudwigSchmidMarreetal.1991,
  author    = {Ludwig, B. and Schmid, A. and Marre, R. and Hacker, J{\"o}rg},
  title     = {Cloning, genetic analysis and nucleotide sequence of a determinant coding for a 19 kd peptidoglycan-associated protein (Ppl) of Legionella pneumophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59721},
  year      = {1991},
  abstract  = {A genomic library of Legionello pneumophihz, the causative agent of Legionnaires disease in humans, was constructed in Escherichill coli K-12, and the recombinant clones were screened by immuno-colony blots with im antiserum raised against heat-killed L. pneumophilo. Twenty-three clones coding for a LegioneUa-specific protein of 19 kDa were isolated. The 19-kDa protein, which represents an outer membrane protein, was found tobe associated with the peptidoglycan layer bothin L. pneumophilo andin the recombinant E. coli clones. This was shown by electrophoresis and Western immunoblot analysis of bacterial cell membrane fractions witb a monospecific polyclonal 19-kDa protein-specific antiserum. Tbe protein was termed peptidoglycan-associated protein of L. pneumophilo (Ppl). The corresponding genetic determinant, ppl, was subcloned on a 1.8-kb Clol fragment. DNA sequence studies revealed that two open reading frames, pplA and pplB, coding for putative proteins of 18~9 and 16.8 kDa, respectively, were located on the Clol fragment. Exonuclease 111 digestion studies confirmed tbat pplA is the gene coding for the peptidoglycan.;.associated 19-kDa protein of L. pneumophilo. The amino acid sequence of PpiA exhibits a high degree of homology to the sequences of the Pal Iipoproteins of E. coli K-12 and liaemophilus injluenvze.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{HackerOttLudwigetal.1991,
  author    = {Hacker, J{\"o}rg and Ott, M. and Ludwig, B. and Rdest, U.},
  title     = {Intracellular survival and expression of virulence determinants of Legionella pneumophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59681},
  year      = {1991},
  abstract  = {Legionella pneumophila, the causative agent of Legionnaires' disease is able to live and multiply within macrophages as weil as within protozoan organisms. Legionella strains inhibit phagosome-lysosome fusion and phagosome acidification. By using two different cell culture systems, one derived from human macrophages and the other from human.embryo lung fibro:blastic cells, it is demonstrated that Legionella strains lose their virulence following cultivation in the laboratory. In order to study the mechanisms involved in intracellular survival of Legionella a genomic library of strain Legionella pneumophila Philadelphia I was established in Escherichia coli K-12. By cosmid cloning technique we were able to clone five putative virulence factors, two of which exhibit hemolytic activities and three of which represent membrane-associated proteins of 19, 26 and 60 kilodalton. One of the hemolytic proteins, termed legiolysin, represents a new toxin which specifically lyses human erythrocytes. The other hemolysin exhibits proteolytic properties in addition and is cytolytic for Vero and CHO cells. Further sturlies will be necessary to determine the exact role of the cloned proteins in the pathogenesis of Legionella. Zusammenfassung: Intrazellul{\"a}res {\"U}berleben},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{BlumOttCrossetal.1991,
  author    = {Blum, G. and Ott, M. and Cross, A. and Hacker, J{\"o}rg},
  title     = {Virulence determinants of Escherichia coli O6 extraintestinal isolates analysed by Southern hybridizations and DNA long range mapping techniques},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59717},
  year      = {1991},
  abstract  = {A total of 16 Escherichia coli 06 strains isolated from cases of extraintestinal infections were analysed for the genetic presence and phenotypic expression of fimbrial adhesins ( P, S/FIC, type I), aerobactin and hemolysin. ln addition restriction fragment length polymorphisms (RFLPs) of Xbal-cleaved genomic DNA of seven selected strains, separated by orthogonal field alternation gel electrophoresis {OFAGE) were determined and virulence-associated DNA probes were used for Southern hybridization studies of the Xbal-cleaved genomic DNAs. The virulence characteristics and hybridization patterns obtained differed between the various isolates. ln three isolates hemolysin genes and P fimbrial determinants were located on the same Xbal fragments. Furthermore, multiple copies of FIC determinants (foc) could be detected in two strains. Our data show that the new technique of pulse field electrophoresis tagether with Southern hybridization represents a powerful tool for the genetic analysis of pathogenic bacteria.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{BenderOttDebesetal.1991,
  author    = {Bender, L. and Ott, M. and Debes, A. and Rdest, U. and Heesemann, J. and Hacker, J{\"o}rg},
  title     = {Distribution, expression and long range mapping of legiolysin gene (lly) specific DNA sequences in Legionellae},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59744},
  year      = {1991},
  abstract  = {The legiolysin gene (lly) cloned from Legionella pneumophila Philadelphia 1 confers the phenotypes of hemolysis and browning of the culture medium. An internal Uy-specific DNA probe was used in Southern hybridizations for the detection of Uy-specific DNA in the genomes of legioneUae and other gram-negative pathogenic bacteria. Under conditi9ns of high stringency, tlie Uy DNA probe specifically reacted with DNA fragments fr9m L. pneumophi{\"u}z isolates; by reducing stringency, hybridization was also observed for all other Legionella strains tested. No hybridization occurred with DNAs isolated from bact~ria of other genera. The Uy genewas mapped by pulsed-field gel electrophoresis to the respective genomic Notl fragments of Legionelltz isolates. By using antilegiolysin monospecific polyclonal antibodies in Western blots (immunoblots), Lly proteins could be detected only in L. pneumophila isolates.},
  subject      = {Infektionsbiologie},
  language  = {en}
}