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Query: UMLS:C0034186 (pyelonephritis)
 6,144 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pyelonephritis-associated pilus (Pap) expression is regulated by a phase variation control mechanism involving PapB, Papl, catabolite activator protein (CAP), leucine-responsive regulatory protein (Lrp) and deoxyadenosine methylase (Dam). Lrp and Papl bind to a specific non-methylated pap regulatory DNA region containing the sequence 'GATC' and facilitate the formation of an active transcriptional complex. Evidence indicates that binding of Lrp and Papl to this region inhibits methylation of the GATC site by Dam. However, if this GATC site is first methylated by Dam, binding of Lrp and Papl is inhibited. These events lead to the formation of two different pap methylation states characteristic of active (ON) and inactive (OFF) pap transcription states. The fae (K88), daa (F1845) and sfa (S) pilus operons share conserved 'GATC-box' domains with pap and may be subject to a similar regulatory control mechanism involving Lrp and DNA methylation.
Mol Microbiol 1992 Sep
PMID:Evidence for global regulatory control of pilus expression in Escherichia coli by Lrp and DNA methylation: model building based on analysis of pap. 135 27

The immunomorphological characteristics of interstitial macrophages with PAS-positive granules were studied in experimental Escherichia coli pyelonephritis in rats, using an anti-E. coli antibody. Immunohistochemical, immunoelectron microscopical, as well as light- and electron microscopical findings were compared at twelve time points between 2 days and 13 weeks after infection. Macrophages with PAS-positive granules were present in the inflammatory infiltrates from the 7th day. The granules were phagolysosomes, filled predominantly with myelin figures. The myelin figures originated mainly from the constituents of the bacterial wall and reacted with the anti-E. coli antibody even 13 weeks after infection. The storage of bacterial residues with preserved antigenic structures for several weeks after infection indicates disturbed phagolysosomal elimination of the bacterial substances in the PAS-positive macrophages. In the formation of macrophages with PAS-positive granules, lysosomal overloading with large amounts of bacteria and cell debris is assumed, leading to consumption of the lysosomal enzymes, consequent incomplete breakdown and retention of the bacterial residues.
Virchows Arch B Cell Pathol Incl Mol Pathol 1990
PMID:Demonstration of bacterial antigen in macrophages in experimental pyelonephritis. 197 36

The Escherichia coli urinary tract isolate C1212 contains two pyelonephritis-associated pili (pap) DNA sequences designated here as pap-17 and pap-21. Each of these pap sequences encodes antigenically-distinct pilin monomers, pilin-17 and pilin-21, respectively. Most individual strain C1212 cells isolated from a single bacterial colony expressed pilin-21. Only a small fraction (5%) of strain C1212 cells expressed pilin-17. Most of the latter population simultaneously expressed pilin-21, but a low percentage of cells expressed pili composed of pilin-17 alone. In contrast, almost every E. coli K-12 cell containing multicopy pap-17 expressed pilin-17 at the cell surface. These results indicated that the regulation of pilin-17 expression observed for strain C1212 was lost when pap-17 was in the multicopy state. Transfer of pap-17 to a single copy vector resulted in a pilin-17 expression frequency lower than strain C1212 (1%). Using E. coli K-12 containing single copy pap-17, we found that the frequency of pilin-17 expression increased about 15-fold when pap-21 was present in multiple copies in trans. Subcloning of pap-21 showed that a 2.2 kilobase-pair DNA sequence adjacent to, but not including, the pilin-21 structural gene was sufficient for activation of pilin-17 expression.
Mol Microbiol 1987 Nov
PMID:The frequency of expression of pyelonephritis-associated pili is under regulatory control. 289 90

We investigated the expression of osteopontin (OPN) messenger (m) RNA in the rat kidney under the experimental models of several conditions that are considered to be risk factors of human renal stones. In the renal stone formation model administrated glyoxylic acid and 1,25-dihydroxyvitamin D3, pyelonephritis model and hydronephrosis model the expression of OPN mRNA in the distal convoluted tubule of the kidney was enhanced compared with the control which was sporadically positive utilizing in situ hybridization and northern blot analysis. The expression of OPN mRNA was markedly inhibited in the renal stone formation model by concominant administration of estradiol and/or progesterone.
Biochem Mol Biol Int 1995 Jan
PMID:Expression of osteopontin messenger RNA in the rat kidney on experimental model of renal stone. 773 36

Escherichia coli strains causing acute pyelonephritis often express multiple fimbrial types and haemolysin, which may contribute to their ability to adhere to, and interact with, kidney epithelial cells. Strain CFT073, a pap+, sfa+, pil+, hly+ pyelonephritis strain, previously established as virulent in the CBA mouse model of ascending urinary tract infection and cytotoxic for cultured human renal epithelial cells, was selected for construction of isogenic strains. From a gene bank of this strain, two distinct copies of the pap operon were isolated. The two P-fimbrial determinants were subcloned into pCVD442, a positive selection suicide vector containing the sacB gene of Bacillus subtilis. Deletion mutations were introduced into each of the two constructs, within papEFG of one operon and papDEFG of the other. Suicide vectors carrying pap deletions were mobilized from E. coli SM10 lambda pir into CFT073 (NalR) and cointegrates were passaged on non-selective medium. The first pap mutation was identified by screening a Southern blot of DNA from sucrose-resistant colonies using a papEFG probe. This mutant retained the MRHA+ phenotype since a second functional copy of pap was still present. A double pap-deletion mutant, UPEC76, confirmed by Southern blotting, was unable to agglutinate human type O erythrocytes or alpha Gal(1-4)beta Gal-coated latex beads. CBA mice (N = 100) were challenged transurethrally with 10(5), 10(6), 10(7), or 10(9) cfu of strains CFT073 or UPEC76. After one week, quantitative cultures of urine, bladder, and kidney were done and histologic changes were examined. No substantive differences in organism concentration or histological findings between parent and mutant were detected in urine, bladder, or kidney at any challenge concentration. We conclude that adherence by P fimbriae of uropathogenic E. coli strain CFT073 plays only a subtle role in the development of acute pyelonephritis in the CBA mouse model.
Mol Microbiol 1993 Oct
PMID:Isogenic P-fimbrial deletion mutants of pyelonephritogenic Escherichia coli: the role of alpha Gal(1-4) beta Gal binding in virulence of a wild-type strain. 796 11

Expression of pyelonephritis-associated pili (Pap) in Escherichia coli is under a phase-variation control mechanism in which individual cells alternate between pili+ (ON) and pili- (OFF) states through a process involving DNA methylation by deoxyadenosine methylase (Dam). Methylation of two GATC sites (GATC1028 and GATC1130) within the pap regulatory region is differentially inhibited in phase ON and phase OFF cells. The GATC1028 site of phase ON cells is non-methylated and the GATC1130 site is fully methylated. Conversely, in phase OFF cells the GATC1028 site is fully methylated whereas the GATC1130 site is non-methylated. Two transcriptional activators, PapI and Lrp (leucine-responsive regulatory protein), are required for this specific methylation inhibition. DNA footprint analysis using non-methylated pap DNAs indicates that Lrp binds to a region surrounding the GATC1130 site, whereas PapI does not appear to bind to pap regulatory DNA. However, addition of Lrp and PapI together results in an additional DNaseI footprint around the GATC1028 site. Moreover, Dam methylation inhibits binding of Lrp/PapI near the GATC1028 site and alters binding of Lrp at the GATC1130 site. Our results support a model in which Dam and Lrp/PapI compete for binding near the GATC1028 site, regulating the methylation state of this GATC site and, consequently, the pap transcription state.
Mol Microbiol 1993 Feb
PMID:Regulation of pyelonephritis-associated pili phase-variation in Escherichia coli: binding of the PapI and the Lrp regulatory proteins is controlled by DNA methylation. 809 19

Tubulointerstitial and periglomerular inflammation and fibrosis are important consequences of pyelonephritis. The pathogenesis of these abnormalities is not fully understood. Renal tubular epithelial cells (RTEC) elaborate biologically active materials following incubation with bacteria. Nitric oxide (NO) is an inflammatory mediator and it modulates the accumulation of extracellular matrix proteins. Therefore, we studied whether RTEC-E. coli interaction products regulate NO production by cultured rat renal medullary interstitial cells (RMIC) and mesangial cells (MC). RMIC and MC were maintained in media containing IFN-gamma and LPS for 24-72 h. Test media contained either no further additives or 20% supernatants from RTEC incubated with E. coli or bacterial cell products. RTEC-E. coli interaction products significantly increased NO production in RMIC and MC. This stimulation in NO production was not associated with changes in inducible nitric oxide synthase (iNOS) gene or protein expression. These findings indicate that RTEC-E. coli interaction products increase NO production in RMIC and MC by directly stimulating iNOS enzymatic activity. Altered NO production by renal cells may contribute to tubulointerstitial inflammation in acute and chronic pyelonephritis.
Res Commun Mol Pathol Pharmacol 1996 Dec
PMID:Renal tubular epithelial cell-E. coli interaction products stimulate nitric oxide production in cultured rat renal medullary interstitial and mesangial cells. 902 69

Pap pili play an important role in the pathogenesis of upper urinary tract infections by enabling uropathogenic Escherichia coli to adhere to host epithelial cells. Pap pili are coded for by the pyelonephritis-associated pili (pap) operon, which consists of 11 genes required for the expression and assembly of Pap pili. Expression of Pap pili is regulated by a phase variation mechanism in which the pili expression state of the bacterial population is skewed between phase-on (expression positive) and phase-off (expression negative) states. Pap phase variation is controlled by the cooperative binding of leucine-responsive regulatory protein (Lrp) to two sets of Lrp binding sites in the upstream regulatory region of the pap operon. A single GATC sequence, which is the target site for deoxyadenosine methylase (Dam), is centrally located within each Lrp binding region. Dam plays a critical role in the expression of Pap pili via the formation of DNA methylation patterns. Methylation of GATC-I reduced the affinity of Lrp for pap DNA by about twofold. Conversely, Lrp specifically blocked methylation of pap GATC-I in vitro. These data support the hypothesis that Lrp and Dam compete for binding to GATC-I, and are consistent with previous results indicating that methylation of GATC-I is important for stability of the phase-off state.
Mol Genet Metab 1998 Nov
PMID:Regulation of uropathogenic Escherichia coli adhesin expression by DNA methylation. 985 83

CS1 pili serve as the prototype for a large class of serologically distinct pili associated with enterotoxigenic Escherichia coli that cause diarrhoea in humans. The four genes essential for CS1 pilus morphogenesis, cooB, A, C and D, are arranged in an operon and encode structural and assembly proteins unlike those of other pilus systems commonly associated with Gram-negative bacteria. CS1 pili are composed primarily of the major pilin subunit, CooA, which determines the serological type of the pilus. The major pilin subunit is assembled into pili by the proteins CooB, CooC and CooD. CooD is both a minor component found at the pilus tip and an essential assembly protein, whereas CooC is an outer membrane protein thought to be involved in pilin transport. CooB is a novel periplasmic chaperone-like protein that forms intermolecular complexes with and stabilizes the major and minor pilins. Unlike other pilin chaperones, CooB also stabilizes the outer membrane component of the assembly system, CooC. The proteins of CS1 pili have no significant homology to those of the well-characterized Pap (pyelonephritis-associated) pili and related systems, although most of the features of pilus morphogenesis are similar. Therefore, these appear to be among the rare cases of convergent evolution. Thus, for CS1 pili, enterotoxigenic E. coli use new protein 'tools' in the old 'trade' of forming functional pili.
Mol Microbiol 1998 Nov
PMID:New tools in an old trade: CS1 pilus morphogenesis. 1009 17

Plasmid-encoded fimbriae (Pef) expressed by Salmonella typhimurium mediate adhesion to mouse intestinal epithelium. The pef operon shares features with the Escherichia coli pyelonephritis-associated pilus (pap) operon, which is under methylation-dependent transcriptional regulation. These features include conserved DNA GATC box sites in the upstream regulatory region as well as homologues of the PapI and PapB regulatory proteins. Unlike Pap fimbriae, which are expressed in a variety of laboratory media, Pef fimbriae were expressed only in acidic, rich broth under standing culture conditions. Analysis of S. typhimurium grown under these conditions indicated that Pef production was regulated by a phase variation mechanism, in which the bacterial population was skewed between fimbrial expression (phase ON) and non-expression (phase OFF) states. Leucine-responsive regulatory protein (Lrp) and DNA adenine methylase (Dam) were required for pef transcription. In contrast, the histone-like protein (H-NS) and the stationary-phase sigma factor (RpoS) repressed pef transcription. Methylation of the pef GATC II site appeared to be required for pef fimbrial expression based on analysis of a GCTC II mutant that did not express Pef fimbriae. Analysis of the DNA methylation states of pef GATC sites indicated that, under acidic growth conditions, which induced Pef production, most GATC I sites were non-methylated, whereas GATC II and GATC X were predominantly methylated. The methylation protection at GATC I and GATC II was dependent upon Lrp and was modulated by PefI. Together, these results indicate that Pef production is regulated by DNA methylation, which is the first example of methylation-dependent gene regulation outside of E. coli.
Mol Microbiol 2000 Feb
PMID:DNA methylation-dependent regulation of pef expression in Salmonella typhimurium. 1069 51


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