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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vitro tissue culture techniques were employed to study the effects of bacterial endotoxins on the growth of normal epithelial cells from the human ureter (NHU). Primary cultures of NHU cells were initiated from explant outgrowth cultures of human ureteral tissue and cultured on collagen gel in F-12* medium containing 1% fetal calf serum (FCS). Optimal clonal growth of secondary cultures of NHU cells seeded at relatively low seeding cell densities, directly on plastic dishes, was achieved in F-12* medium containing bovine pituitary extract (0.5% BPE) and 0.05% BSA. Results indicated that insulin in the F-12* medium could be replaced by three orders of magnitude less IGF-1. Further clonal growth experiments demonstrated that PGE1 is growth stimulatory and can replace BPE as a growth factor requirement. This finding was in agreement with the fact that BPE growth requirement could be replaced by cholera toxin or dibutyryl cAMP. These results suggested that both BPE and cholera toxin operated by activation of a cAMP-dependent mitogenic pathway. Seven gram-negative bacterial lipopolysaccharides (LPS) and three gram-positive bacterial lipotechoic acids (LT) were tested for their effects on NHU clonal growth. Three out of the five LPS derived from Escherichia coli (strains 055:B5, 0128:B12, and 0127:B8), LPS from Klebsiella pneumoniae, and LPS from Pseudomonas aeruginosa all showed significant growth inhibitory effects at minimally effective doses ranging from 5 to 25 micrograms/ml. LPS derived from E. coli strain (0111:B4) had no growth effects at the highest concentration tested (100 micrograms/ml). In contrast, LT derived from Streptococcus pyogenes, S. faecalis, Staphylococcus aureas, and Bacillus subtilis all markedly enhanced clonal growth at concentrations ranging from 1 microgram/ml less than [LT] less than 50 micrograms/ml. LT from Strep. pyogenes was inhibitory to clonal growth at 100 micrograms/ml. The growth inhibitory effects of LPS were shown to be sensitive to the presence of hydrocortisone in the growth medium, indicating that LPS effects on growth are mediated via the arachidonic acid cascade. We speculate that these results indicate a link between the susceptibility of uroepithelial tissue to the pathogenic microflora seen in urinary tract diseases and the differential sensitivity of proliferation-competent uroepithelial cells to growth inhibition by LPS produced by gram-negative bacteria. However, further studies with uropathogenic serotypes will be necessary to corroborate this possibility. The growth-stimulating activity of LTs produced by gram-positive bacteria may be due to their ability to bind to cell-associated fibronectin and to activate the fibronectin receptor as part of ligand receptor-induced mitogenic transmembrane signalling pathway.
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PMID:Effects of growth factors, hormones, bacterial lipopolysaccharides, and lipotechoic acids on the clonal growth of normal ureteral epithelial cells in serum-free culture. 173 Jul 86

This study reports an in vitro system that allows the convenient study of both microenvironmental and bacterial factors affecting adherence of Pseudomonas aeruginosa to tracheal epithelium. Primary cultures of mixed ciliated and nonciliated epithelial cells isolated from hamster tracheas were grown on collagen-coated multiwell plates containing 10(5) epithelial cells/well at confluence. When 10(7) 14C-labeled P. aeruginosa (nonmucoid, strain Y-4) suspensions were added to each well, 8.13 +/- 2.6% (mean +/- SD) of the initial inoculum bound to the cultured cells, an amount comparable to that measured using suspensions of human tracheal epithelial cells and the same bacteria. The bacteria adhered preferentially to the cultured cells rather than to an acellular collagen matrix. Five additional nonmucoid strains of P. aeruginosa also bound well to the cultured cells, while two mucoid strains were less adherent. Strains of two other gram-negative bacteria, Pseudomonas maltophilia and Klebsiella pneumoniae, did not bind significantly, emphasizing the bacterial species specificity of the adherence interaction being measured. The binding interaction with P. aeruginosa was both pH-sensitive and altered by the presence of the divalent cation calcium. Thus, the in vitro assay system described provides a consistent surface of tracheal epithelial cells that binds P. aeruginosa in a specific manner and can be used to examine the effects of bacterial variables and microenvironmental conditions that may be present in the human airway.
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PMID:Characterization of Pseudomonas aeruginosa adherence to cultured hamster tracheal epithelial cells. 195 84

Tissue-binding specificity of the type-3 fimbriae of pathogenic enteric bacteria was determined using frozen sections of human kidney. A wild-type Klebsiella sp. strain and the recombinant strain Escherichia coli HB101(pFK12), both expressing type-3 fimbriae, as well as the purified type-3 fimbriae effectively bound to sites at or adjacent to tubular basement membranes, Bowman's capsule, arterial walls, and the interstitial connective tissue. Bacterial adherence to kidney was decreased after collagenase treatment of the tissue sections. Recombinant strains expressing type-3 fimbriae specifically adhered to type V collagen immobilized on glass slides, whereas other collagens, fibronectin or laminin did not support bacterial adherence. In accordance with these findings, specific binding of purified type-3 fimbriae to immobilized type V collagen was demonstrated. Specific adhesion to type V collagen was also seen with the recombinant strain HB101(pFK52/pDC17), which expresses the mrkD gene of the type-3 fimbrial gene cluster in association with the pap-encoded fimbrial filament of E. coli, showing that the observed binding was mediated by the minor lectin (MrkD) protein of the type-3 fimbrial filament. The interaction is highly dependent on the conformation of type V collagen molecules since type V collagen in solution did not react with the fimbriae. Specific binding to type V collagen was also exhibited by type-3 fimbriate strains of Yersinia and Salmonella, showing that the ability to use type V collagen as tissue target is widespread among enteric bacteria.
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PMID:Type V collagen as the target for type-3 fimbriae, enterobacterial adherence organelles. 198 Jul 13

The promotion of healing of large abscess cavities attained with topical phenytoin was evaluated in controlled studies of clinical and experimental wounds. In the clinical abscess cavities, phenytoin application in 20 patients compared with conventional treatment in 20 patients resulted in earlier separation of slough, decrease in oedema, control of pain and overall enhanced healing. The mean(s.d.) rate of reduction of wound area was 2.02(0.48) cm2/day in the phenytoin group versus 1.58(0.51) cm2/day in controls (P less than 0.05) on day 10, and 1.8(0.32) cm2/day versus 1.19(0.21) cm2/day (P less than 0.01) on day 20. The mean volume reduction rates at both the 10th and 20th day were 0.48(0.01) cm3/day for phenytoin versus 0.32(0.04) cm3/day for controls; (P less than 0.005). By day 20, 17 of the patients treated with phenytoin were rated as having healed completely, compared with only one of the controls. In a standardized guinea-pig model of the clinical abscess cavity, which included inoculation of the wound with Bacillus proteus and Klebsiella pneumoniae, an enhanced healing rate was also observed (at 7 days 0.40(0.05) cm2/day with phenytoin versus 0.21(0.08) cm2/day in controls; P less than 0.005). All eight of the animals treated with phenytoin healed by day 21, compared with one of the eight controls. Biopsies of wounds treated with phenytoin showed less inflammation, no necrosis, and enhanced neovascularization, collagen deposition and fibroblast proliferation compared to controls. Bacterial colonies also decreased more rapidly with the use of phenytoin.
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PMID:Role of phenytoin in healing of large abscess cavities. 199 49

Parainfluenza 1 (Sendai) and influenza A virus pneumonitis cause severe lung damage, which, upon resolution, is followed by persistent alveolitis and parenchymal changes characterized by patchy consolidation and collagen deposition in the affected areas. To determine whether these long-term sequelae of the virus pneumonias are cumulative, mice were infected by aerosol inhalation with Sendai virus, influenza A virus, or Sendai followed 30 days later by influenza virus infection. At 90 days after the initial infection, mice were killed for assay of long-term parenchymal changes as quantitated lung hydroxyproline (Hpr) content, morphometric analysis, and total and differential lavage cell counts. Sendai virus infection did not alter the proliferation of influenza virus in the lungs as quantitated by infectious virus titers on Day 1, 3, 5, 7, 9, and 11 of influenza infection. At Day 90, lung Hpr content was cumulative in dual-infected mice, with a concomitant increase in the persistent alveolitis. To determine whether bacterial infections played a similar role in these long-term pulmonary sequelae, mice were infected by aerosol inhalation with either Staphylococcus aureus or Klebsiella pneumoniae or, during the course of influenza virus infection, superinfected with each of the bacteria. Sixty days after infection with K. pneumoniae alone, lung Hpr levels were significantly increased over those in noninfected control mice. Infection with S. aureus had no effect on the quantitated parameters of long-term lung damage. In influenza-infected mice superinfected with K. pneumoniae, lung Hpr content was significantly increased over that of S. aureus did not elevate any quantitated parameter of lung damage when compared with the virus alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sequential virus infections, bacterial superinfections, and fibrogenesis. 216 56

The determined nucleotide sequence of the Klebsiella pneumoniae UNF5023 gene pulA comprises a single open reading frame coding for a 1090-residue precursor of the secreted protein pullulanase. The predicted sequence of this protein is highly homologous to that of pullulanase of Klebsiella aerogenes strain W70. However, the UNF5023 pullulanase lacks a collagen-like sequence present at the N-terminus of the mature W70 enzyme and differs further from the W70 pullulanase around residue 300 and at the C-terminus. Pullulanases with or without the collagen-like sequence could not be separated by gel electrophoresis under denaturing or non-denaturing conditions, and were unaffected by collagenase. A large central domain which is highly conserved in both UNF5023 and W70 polypeptides contains eight short sequences that are also found in amylases and iso-amylases. Linker mutations in the region of the UNF5023 pulA gene coding for this domain abolished catalytic activity without affecting transport of the polypeptide across the outer membrane. Hybrid proteins comprising at least the amino-terminal 656 residues of prepullulanase fused to alkaline phosphatase were partially localized to the cell surface, as judged by their accessibility to anti-pullulanase serum in immuno-fluorescence tests. On the basis of these results, we tentatively propose that secretion signals required for recognition and translocation across the outer membrane via the pullulanase-specific extension of the secretion pathway are located near the N-terminus of the pullulanase polypeptide.
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PMID:Molecular characterization of pulA and its product, pullulanase, a secreted enzyme of Klebsiella pneumoniae UNF5023. 218 Dec 42

Pullulanase from Klebsiella pneumoniae strain FG9 has an unusual N-terminal amino acid sequence that includes six repeats of the tripeptide Gly-X-Pro. This type of sequence is characteristic of animal collagens and collagen-like proteins which form triple helical structures. We have investigated the molecular organization of this bacterial pullulanase isolated from the cell surface of Escherichia coli cells that carry the cloned FG9 pulA (pullulanase encoding) gene. Non-denaturing polyacrylamide gel analysis shows that pullulanase exists as higher order, apparently homogeneous, structures. We have used highly purified bacterial collagenase to probe the role of the collagen-like region and we demonstrate that this feature is essential for non-covalent association of pullulanase homotrimers. In addition we show collagenase-specific release of cell-bound pullulanase.
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PMID:Collagen-like sequences stabilize homotrimers of a bacterial hydrolase. 284 88

Molecular mimicry has been shown between two sequences of Klebsiella pneumoniae pulD secretion protein (DRDE) with HLA-B27 (DRED) and pulA (pullulanase) enzyme (Gly-X-Pro) with types I, III and IV collagen respectively. IgG antibody levels in AS patients were elevated against 16mer synthetic peptides of HLA-B27 and pulD by enzyme immunosorbent assay (ELISA) compared to controls (P < 0.001). ELISA assays against K. pneumoniae grown in the absence and presence of pullulan demonstrated significant levels of IgA antibody in AS patients compared to controls (P < 0.001). Increased IgA and IgG antibody levels to pulA and types I and IV collagen were observed in AS patients compared to controls (P < 0.001). These observations could be relevant in the sequence of molecular events in AS.
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PMID:Molecular mimicry and ankylosing spondylitis: possible role of a novel sequence in pullulanase of Klebsiella pneumoniae. 764 65

The type 3 fimbriae of enteric bacteria mediate agglutination, in vitro, of erythrocytes treated with tannic acid. The gene encoding the polypeptide, MrkD, that mediates this agglutination reaction was placed downstream of an inducible promoter, and the ability of MrkD alone to facilitate hemagglutination was determined. Although Escherichia coli transformants could be shown to produce the MrkD protein, hemagglutination did not occur in the absence of other mrk gene products. In addition, the MrkD polypeptide did not cross the bacterial outer membrane unless a fimbrial chaperone protein was also present. Analysis of the frequency of the mrkD gene within the genus Klebsiella indicated that this gene is conserved in strains of Klebsiella oxytoca but not in other fimbriate Klebsiella species. In the small number of strains of Klebsiella pneumoniae that do possess a related mrkD gene, this determinant could be found on a plasmid in one strain. The ability of type 3 fimbriate bacteria to adhere to type V collagen was found to be a function of a specific MrkD polypeptide. This adhesin is frequently found in strains of K. oxytoca but is rarely associated with the type 3 fimbriae of K. pneumoniae.
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PMID:The type 3 fimbrial adhesin gene (mrkD) of Klebsiella species is not conserved among all fimbriate strains. 792 74

The interaction between C1q, a subcomponent of the complement classical pathway component C1, and OmpK36, a porin protein from Klebsiella pneumoniae, was studied in a solid-phase direct-binding assay, inhibition assays with the purified globular and collagen-like regions of C1q, and cross-linking experiments. We have shown that the binding of C1q to the OmpK36 porin of the serum-sensitive strain K. pneumoniae KT707 occurs in an in vivo situation and that this binding leads to activation of the complement classical pathway and the subsequent deposition of complement components C3b and C5b-9 on the OmpK36 porin. Scatchard analysis of the binding of [125I]C1q to the OmpK36 porin showed two binding sites with dissociation constants of 1.5 and 75 nM. The decrease of [125I]C1q binding to the OmpK36 porin in buffer with increasing salt concentrations and the pIs of the C1q subcomponent (10.3) and OmpK36 porin (4.5) suggest that charged amino acids are involved in the binding phenomenon. In inhibition assays, only the globular regions of C1q inhibited the interaction between C1q and OmpK36 porin, demonstrating that C1q binds to porin through its globular region and not through the collagen-like stalks.
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PMID:Interaction between complement subcomponent C1q and the Klebsiella pneumoniae porin OmpK36. 889 Feb 31


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