@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}
}
@article{BenderOttMarreetal.1990,
  author    = {Bender, L. and Ott, M. and Marre, R. and Hacker, J{\"o}rg},
  title     = {Genome analysis of Legionella spp. by orthogonal field alternation gel electrophoresis (OFAGE)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59657},
  year      = {1990},
  abstract  = {Various Legionella isolates from different sources and origins were analysed by orthogonal field alternation gel electrophoresis of Not I cleaved genomic DNA. The genome of L pneumophila Philadelphia I, the original isolate of the epidemics in 1976, exhibits only five Not I fragments. Two virulent derivatives. derived from L pneumophila Philadelphia I. which were obtained by prolonged passage on artificial cuhure media, did not differ from their isogenic virulent strain according the Not I fragment pattern. By summing the lengths of the Notl fragments, the genome size of L. pneumophila Philadelphia I was calculated as approximately 3.9 Mb. Environmental L pneumophila strains exhibited different Not I pattems, as did Legionella strains not belongi'ng to the species pneumophila. The usefulness of DNA long range mapping of Legionella ssp. with Notl for epidemiology and evaluation of their evolutionary rela· tionships is discussed.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{BergerHackerJuarezetal.1982,
  author    = {Berger, Harald and Hacker, J{\"o}rg and Juarez, Antonio and Hughes, Colin and Goebel, Werner},
  title     = {Cloning of the chromosomal determinants encoding hemolysin production and mannose-resistant hemagglutination in Escherichia coli},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40255},
  year      = {1982},
  abstract  = {We have cloned the chromosomal hemolysin determinants from Escherichia coli strains belonging to the four O-serotypes 04, 06, 018, and 075, The hemolysin-producing clones were isolated from gene banks of these strains which were constructed by inserting partial Sau3A fragments of chromosomal DNA into the cosmid pJC74. The hemolytic cosmid clones were relatively stable. The inserts were further sub cloned either as Sail fragments in pACYC184 or as BamHI-SaLI fragments in a recombinant plasmid (pANN202) containing cistron C (hlye) of the plasmid-encoded hemolysin determinant. Detailed restriction maps of each of these determinants were constructed, and it was found that, despite sharing overall homology, the determinants exhibited minor specific differences in their structure, These appeared to be restricted to cistron A (hlyA), which is the structural gene for hemolysin. In the gene banks of two of these hemolytic strains, we could also identify clones which carried the genetic determinants for the mannose-resistant hemagglutination antigens Vb and VIc. Both of these fimbrial antigens were expressed in the E. coli K-12 clones to an extent similar to that observed in the wild-type strains. These recombinant cosmids were rather unstable, and, in the absence of selection, segregated at a high frequency.},
  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{ChakrabortyKathariouHackeretal.1987,
  author    = {Chakraborty, Trinad and Kathariou, Sophia and Hacker, J{\"o}rg and Hof, Herbert and Huhle, Burkhard and Wagner, Wilma and Kuhn, Michael and Goebel, Werner},
  title     = {Molecular analysis of bacterial cytolysins},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40328},
  year      = {1987},
  abstract  = {Results of molecular and pathogenic studies of three different bacterial hemolysins (cytolysins) are presented. These exoproteins derive from the two gram-negative bacteria Escherichia coli and Aeromonas hydrophila and from the gram-positive pathogen Listeria monocytogenes. The hemolysin of E. coli is determined by an 8-kilobase (kb) region that includes four clustered genes (hlyC, hlyA, hlyB, and hlyD). This hemolysin determinant is part either of large transmissible plasmids or of the chromosome. The genes located chromosomally are found predominantly in E. coli strains that can cause pyelonephritis and/or other extraintestinal infections. A detailed analysis of the chromosomal hly determinants of one nephropathogenic E. coli strain revealed the existence of specific, large chromosomal insertions 75 kb and lOO kb in size that carry the hly genes but that also influence the expression of other virulence properties, i.e., adhesion and serum resistance. The direct involvement of E. coli hemolysin in virulence could be demonstrated in several model systems. The genetic determinants for hemolysin (cytolysin) formation in , A. hydrophila (aerolysin) and L. monocytogenes (listeriolysin) are less complex. Both cytolysins seem to be encoded by single genes, although two loci (aerB and aerC) that affect the expression and activity of aerolysin have been identified distal and proximal to the structural gene for aerolysin (aerA). Cytolysin-negative mutants of both bacteria were obtained by site-specific deletion and/or transposon mutagenesis. These mutants show a drastic reduction in the virulence of the respective bacteria.},
  language  = {en}
}
@article{FischerBangLudwigetal.1992,
  author    = {Fischer, G. and Bang, H. and Ludwig, B. and Mann, K. H. and Hacker, J{\"o}rg},
  title     = {Mip protein of Legionella pneumophila exhibits peptidyl-prolyl cis-trans-isomerase (PPIase) activity},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59778},
  year      = {1992},
  abstract  = {Legfonells pneumoph/la is an intracellular paraslte which ts able to survtve and multipJy in human monocytes and alveolar macrophages. The Mtp (macrophage lnfectiv1ty potentlator) protein has been shown to be an essential virulente factor. A search of translated nuclelt .acld data ba.ses has shown that the Mip proteJn from strain Wadsworth possesses reglons homologaus to those found in the FK.506-bindfng proteins (FKBPs) of several different eukaryotlc organisms. FKBPs are abte to bind to the fmmunosuppressant macrollde FK506 and possess peptidyf .. prolyl cisltrans Isomerase (PPiase) activlty. The gene coding for the Mlp proteln was cloned from the ehromo. some of L. pneumophila straln Philadelph·a I and sequenced. II was synthesl\%ed in Escherichla coll ·K- 12 and alter purlfication it exhibited PPiase activity catalyslng the slow clsltrans lsomerization of prolyl peptlde bonds. ln ollgopeptides. Mip ls inhibi~ted by FK506 and fully reslstant to cyclosporln A, as was also found for the recently characterlzed FKBP-type PPiases of eukaryotes. However, the N-terminal extenslon of Mip and/or the substltutrons of the vari· ab1e amlno acrds ln the C-termlnal FKBP core Iead to variatlons,. when compared with eukaryotlc FKBPs, Jn substrate specfflclty wlth the Oligopeptide substrates of' type Suc-Aia-Xaa-Pro-Phe·4·nitroanUide. Never· theless, the Legionella Mip factor represents a bacte· rial gene product whtch shares some characteristics normally found in eukaryotic proteins. ln view of the activity of PPiases in protein-folding reactlonsf such prokaryotic FKBP analogues may represent a new class of bacterial. pathogenicity factors.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{HackerBenderOttetal.1990,
  author    = {Hacker, J{\"o}rg and Bender, L. and Ott, M. and Wingeder, J. and Lund, B. and Marre, R. and Goebel, W.},
  title     = {Deletions of chromosomal regions coding for fimbriae and hemolysins occur in vivo and in vitro in various extraintestinal Escherichia coli isolates},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59608},
  year      = {1990},
  abstract  = {No abstract available},
  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{HackerHofEmoedyetal.1986,
  author    = {Hacker, J{\"o}rg and Hof, H. and Em{\"o}dy, L. and Goebel, W.},
  title     = {Influence of cloned Escherichia coli hemolysin genes, S fimbriae and serum resistance on pathogenicity in different animal models},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59423},
  year      = {1986},
  abstract  = {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.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{HackerHofHughesetal.1985,
  author    = {Hacker, J{\"o}rg and Hof, H. and Hughes, C. and Goebel, W.},
  title     = {Salmonella typhimurium strains carrying hemolysin plasmids and cloned hemolysin. genes from Escherichia coli},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40309},
  year      = {1985},
  abstract  = {Like all other Salmonella typhimurium strains examined, the smooth variants SF1397 (L T2) and 1366 and also their semi-rough and rough derivatives are non-haemolytic. Nevertheless, two haemolysin (Hly) plasmids of E. coli belonging to the inc groups incFllI,lv (pSU316) and incIz (pHly152) were able to be introduced into these strains by conjugation and stably maintained. A considerable percentage of the Hly+ transconjugants obtained had lost parts of their O-side chains, a result of selection for the better recipient capability of « semi-rough» variants rather than the direct influence of the Hly+ plasmids themselves. In contrast to the incF1lI1V plasmid pSU316, which exhibited higher conjugation rates with rough recipients, the incIz plasmid pHly152 was accepted best by smooth strains. Transformation with cloned E. coli haemolysin (hly) determinant was inefficient ( <10-8) for smooth strains, but 102-103 times higher for rough recipients, and was increased by the use of Salmonella-modified DNA. The transform ants and transconjugants were relatively stable and showed the same haemolytic activity as the E. coli donor strains. The virulence of the Hly+ smooth, semi-rough and rough S. typhimurium strains was tested in two mouse models, and neither the mortality rate nor the ability to multiply within the mouse spleen was influenced by the hly determinants.},
  language  = {en}
}
@article{HackerHughesHofetal.1983,
  author    = {Hacker, J{\"o}rg and Hughes, C. and Hof, H. and Goebel, W.},
  title     = {Cloned hemolysin genes from Escherichia coli that cause urinary tract infection determine different levels of toxicity in mice},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59330},
  year      = {1983},
  abstract  = {After intraperitoneal injection of mice with Escherichia coli strains isolated from patients with urinary tract infections, the mortality due to hemolytic (Hly+) and nonhemolytic (Hiy-) isolates was 77 and 40\%, respectively. Deletion of the chromosomal hemolysin (h/y) determinant in an E. co/i 06:K15:H31 urinary tract infection strain led to a significant reduction in toxicity for mice, and its reintroduction on a recombinant plasmid partially restored the original toxicity. Although introduction of the cloned plasmid pHiy152-encoded hly determinant into the Hly- E. coli 06 mutant strain increased toxicity by only a marginal degree, transformation with the cloned chromosomal hly determinants from two E. coli strains of serotypes 018ac:K5:H- and 075:K95:H? resulted in markedly greater toxicity, even exceeding that of the original Hly+ E. coli 06 wild-type strain.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{HackerKestlerHoschuetzkyetal.1993,
  author    = {Hacker, J{\"o}rg and Kestler, H. and Hosch{\"u}tzky, H. and Jann, K. and Lottspeich, F. and Korhonen, T. K.},
  title     = {Cloning and characterization of the S fimbrial adhesin (SfaII) complex of an Escherichia coli O18:K1 meningitis isolate},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59853},
  year      = {1993},
  abstract  = {S fimbrial adbesins (Sfa), which are able to recognize sialic acid-containing receptors on eukaryotic cells, are produced by Escherichia coli strains causing urinary tract infections or newbom meningitis. We recently described tbe cloning and molecular cbaracterization of a determinant, termed sftJI, from the chromosome of an E. coli urinary tract infection strain. Herewe present data conceming a S fimbria-specific gene duster, designated sfall, of an E. coli newbom meningitis strain. Like tbe Sfal complex, Sfall consists of tbe major subunit protein SfaA (16 kDa) and the minor subunit proteins SfaG (17 kDa), SfaS (15 kDa), and SfaH (29 kDa). The genes encoding tbe subunit proteins of Sfall were identified and sequenced. Their protein sequences were calculated from the DNA sequences and compared with tbose of the Sfal complex subunits. Altbough the sequences ofthe two major SfaA subunits ditf'ered markedly, tbe sequences ofthe minor subunits sbowed only a few amino acid exchanges (SfaG, SfaH) or were completely identical (SfaS). The introduction of a site-specific mutation into the gene sfaSII and subsequent analysis of an SfaS-negative clone indicated that sfaSII codes for the sialic acid-specific adhesin of tbe meninigitis isolate. These data were confirmed by tbe isolation and characterization of tbe SfaSII protein and the determination of its N-terminal amino acid sequence. The identity between the sialic acid-specific adhesins of Sfal and Sfall revealed that difl'erences between the two Sfa complexes with respect to tbeir capacities to agglutinate erythrocytes must result from sequence alterations of subunit proteins other tban SfaS.},
  subject      = {Infektionsbiologie},
  language  = {en}
}
@article{HackerKnappGoebel1983,
  author    = {Hacker, J{\"o}rg and Knapp, S. and Goebel, W.},
  title     = {Spontaneous deletions and flanking regions of the chromosomal inherited hemolysin determinant of an Escherichia coli 06 strain},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40260},
  year      = {1983},
  abstract  = {The hemolytic Escherichia coli strain 536 (06) propagates spontaneous hemolysin- negative mutants at relatively high rates (10-3 to 10-4 ). One type of mutant (type I) lacks both secreted (external) and periplasmic (internal) hemolysin activity (HlYex - IHlYin -) and in addition shows no mannose-resistant hemagglutination (Mrh -), whereas the other type (type II) is HlYex -IHIYin + and Mrh +. The genetic determinants for hemolysin production (hly) and for mannose-resistant hemagglutination (mrh) of this strain are located on the chromosome. Hybridization experiments with DNA probes specific for various parts of the hly determinant reveal that mutants of type I have lost the total hly determinant, whereas those of type 11 lack only part of the hlyB that is essential for transport of hemolysin across the outer membrane. Using a probe that contains the end sequence of the plasmid pHly152-encoded hly determinant (adjacent to hlyB), we determined that a related sequence flanks also the hlyB-distal end of the chromosomal hly determinant of E. coli 536. In addition several other similar or even identical sequences are found in the vicinity of the hlyC- and the hlyB-distal ends of both the chromosomal and the plasmid hly determinants.},
  language  = {en}
}
@article{HackerOttHof1993,
  author    = {Hacker, J{\"o}rg and Ott, M. and Hof, H.},
  title     = {Effects of low, subinhibitory concentrations of antibiotics on expression of a virulence gene cluster of pathogenic E. coli by using a wild-type gene fusion},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59874},
  year      = {1993},
  abstract  = {No abstract available},
  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{HackerOttSchmidtetal.1986,
  author    = {Hacker, J{\"o}rg and Ott, M. and Schmidt, G. and Hull, R. and Goebel, W.},
  title     = {Molecular cloning of the F8 fimbrial antigen from Escherichia coli},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59391},
  year      = {1986},
  abstract  = {The genetic determinant coding for the Pspecific F8 fimbriae was cloned from · the chromosome of the Escherichia coli wild-type strain 2980 (018: K5: H5: FlC, F8). The F8 determinant was further subcloned into the Pstl site of pBR322 and a restriction map was established. In a Southern hybridization experiment identity between the chromosomally encoded F8 determinant of 2980 and its cloned Counterpart was demonstrated. The cloned F8 fimbri{\"a}e and those of the wild type strain consist of a protein subunit of nearly 20 kDa. F8 fimbriated strains were agglutinated by an F8 polyclonal antiserum, caused mannose-resistant hemagglutination and attached to human uroepi thellal cells. The cloned F8 determinant was weil expressed in a variety of host strains.},
  subject      = {Infektionsbiologie},
  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{HackerOttWintermeyeretal.1993,
  author    = {Hacker, J{\"o}rg and Ott, Manfred and Wintermeyer, Eva and Ludwig, Birgit and Fischer, Gunter},
  title     = {Analysis of virulence factors of Legionella pneumophila.},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70620},
  year      = {1993},
  abstract  = {Legionella pneumophila, the causative agent of Legionnaires' disease is a facultative intracellular bacterium, which in the course of human infection multiplies in lung macrophages predominantly manifesting as pneumonia. The natural habitat of Legionella is found in sweet water reservoirs and man-made water systems. Virulent L. pneumophila spontaneously convert to an avirulent status at a high frequency. Genetic approaches have led to the identification of various L. pneumophila genes. The mip (macrophage infectivity potentiator) determinant remains at present the sole established virulence factor. The Mip protein exhibits activity of a peptidyl prolyl cis trans isomerase (PPiase), an enzyme which is able to bind the immunosuppressant FK506 and is involved in protein folding. The recently cloned major outer membrane protein (MOMP) could play a role in the uptake of legionellae by macrophages. Cellular models are useful in studying the intracellular replication of legionellae in eukaryotic cells. Human celllines and protozoan models are appropriate for this purpose. By using U 937 macrophage-like cells and Acanthamoeba castellanii as hosts, we could discriminate virulent and avirulent L. pneumophila variants since only the virulent strain was capable of intracellular growth at 37 oc. By using these systems we further demonstrated that a hemolytic factor cloned and characterized in our laboratory, legiolysin (lly), had no influence on the intracellular growth of L. pneumophila.},
  subject      = {Legionella pneumophila},
  language  = {en}
}
@article{HackerRdestWintermeyeretal.1991,
  author    = {Hacker, J{\"o}rg and Rdest, Ursula and Wintermeyer, E. and Ludwig, B.},
  title     = {Legiolysin, a New Hemolysin from L. pneumophila},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-73070},
  year      = {1991},
  abstract  = {Legionella pneumophila generares exotoxins, cytolysins, proteases oc hemolysins that darnage host cells llke erythrocytes or rissue cu lrure cells. The gene for a new L. pneumophila hemolysin withour a proteolytic activiry was idemified, cloned in E. coli and sequenced. The gene producr was analysed by SDS-Polyacrylamide-gel-electrophoresis.},
  subject      = {H{\"a}molysin},
  language  = {en}
}
@article{HackerSchmidtHughesetal.1985,
  author    = {Hacker, J{\"o}rg and Schmidt, G. and Hughes, C. and Knapp, S. and Marget, M. and Goebel, W.},
  title     = {Cloning and characterization of genes involved in the production of mannose-resistant, neuraminidase-susceptible (X) fimbriae from an uropathogenic O6:K15:K31 Escherichia coli strain},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59353},
  year      = {1985},
  abstract  = {The Qropathogenic Escherichia coli strain 536 (06:K15:H31) exhibits a mannose-resistant hemagglutination phenotype (Mrh) with bovine erythrocytes and delayed Mrh with human and guinea pig erythrocytes. Neuraminidase treatment of the erythrocytes abolishes mannose resistant hemagglutination, which is typical for X fimbriae. E. coli strain 536 synthesizes two different fimbriae (Fim phenotype) prQtein subunits, 16.5 and 22 kilodaltons in size. In addition the strain shows mannose-sensitive hemagglutination and common type I (Fl) fimbriae. The cosmid clone E. coli K-12(pANN801) and another nine independently isolated Mrh+ cosmid clones derived from a cosmid gene bank of strain 536 express the 16.5-kilodalton protein band, bot not the 22-kilodalton protein, indicating an association of the Mrh+ property with the "16.5-kilodalton fimbriae." All cosmid clones were fimbriated, and they reacted with antiserum produced against Mrh+ fimbriae of the E. coli strain HB101(pANN801) and lacked mannose-sensitive hemagglutination (Fl) funbriae. From the Mrh fim cosmid DNA pANN801, several subclones coding for hemagglutination and X fimbriae were constructed. Subclones that express both hemagglutination and fimbriae and subclones that only code for the hemagglutination antigen were isolated; subclones that only produce fimbriae were not detected. By transposon Tn5 mutagenesis we demonstrated that about 6.5 kilobases of DNA is required for the Mrh+ Fim+ phenotype, and the 1.5- to 2-kilobase DNA region coding for the structural proteiil of the fimbriae has been mapped adjacent to the region responsible for the Mrh+ phenotype. Two different regions can thus be distinguished in the adhesion determinant, one coding for hemagglutination and the other coding for fimbria formation. Transformation of plasmid DNA from these subclones into a Mrh- Fim- mutant of E. coli 536 and into a galE (rough) strain of Salmonella typhimurium yielded transformants that expressed both hemagglutination and fimbria production.},
  subject      = {Infektionsbiologie},
  language  = {en}
}