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Letteratura scientifica selezionata sul tema "Pili (Microbiology)"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 20 febbraio 2023

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Articoli di riviste sul tema "Pili (Microbiology)"

1

Hendrickx, Antoni P. A., Claudia M. E. Schapendonk, Miranda van Luit-Asbroek, Marc J. M. Bonten, Willem van Schaik e Rob J. L. Willems. "Differential PilA pilus assembly by a hospital-acquired and a community-derived Enterococcus faecium isolate". Microbiology 156, n. 9 (1 settembre 2010): 2649–59. http://dx.doi.org/10.1099/mic.0.041392-0.

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Abstract (sommario):
Pili are hair-like structures protruding from the cell envelope of bacterial cells. Here, we describe the conditional and differential display of PilA-type pili, and PilE and PilF proteins, encoded from pilin gene cluster 1 at the surface of a hospital-acquired Enterococcus faecium bloodstream isolate (E1165) and a community-derived stool isolate (E1039), at two different temperatures. Both strains have virtually identical pilA gene clusters, as determined by sequencing. Western blotting and transmission immunoelectron microscopy revealed that PilA and PilF assembled into high-molecular-mass pilus-like structures at 37 °C in the E1165 strain, whereas PilE was not produced at either of the temperatures used; at 21 °C, PilA and PilF were cell-wall-anchored proteins. In contrast, in strain E1039, PilA, PilE and PilF pilin proteins were found to be displayed as cell-wall-anchored proteins at 37 °C only, and they were not associated with pilus-like structures. The discrepancy in pilus assembly between E1039 and E1165 cannot be explained by differences in expression of the genes encoding the predicted sortases in the pilA gene cluster, as these had similar expression levels in both strains at 21 and 37 °C. Double-labelling electron microscopy revealed that PilA formed the pilus backbone in E1165, and PilF the minor subunit which was distributed along the PilA pilus shaft and positioned at the tip; however, it was deposited as a cell-wall-anchored protein in a pilA isogenic mutant. The differential deposition of surface proteins from pilin gene cluster 1 and differences in pilus assembly in the two strains suggest a complex post-transcriptional regulatory mechanism of pilus biogenesis in E. faecium.
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2

Sauvonnet, Nathalie, Pierre Gounon e Anthony P. Pugsley. "PpdD Type IV Pilin of Escherichia coliK-12 Can Be Assembled into Pili in Pseudomonas aeruginosa". Journal of Bacteriology 182, n. 3 (1 febbraio 2000): 848–54. http://dx.doi.org/10.1128/jb.182.3.848-854.2000.

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Abstract (sommario):
ABSTRACT Escherichia coli K-12 possesses at least 16 chromosomal genes related to genes involved in the formation of type IV pili in other gram-negative bacteria. However, E. coli K-12 does not produce type IV pili when grown under standard laboratory conditions. The results of reverse transcription-PCR, operon fusion analysis, and immunoblotting demonstrated that several of the putativeE. coli piliation genes are expressed at very low levels. Increasing the level of expression of the major pilin gene (ppdD) and the linked assembly genes hofB andhofC (homologues of the Pseudomonas aeruginosatype IV pilus assembly genes pilB and pilC) did not lead to pilus production. However, expression of theppdD gene in P. aeruginosa led to assembly of PpdD into pili that were recognized by antibodies directed against the PpdD protein. Assembly of PpdD into pili in P. aeruginosawas dependent on the expression of the pilB andpilC genes and independent of expression of the P. aeruginosa pilin structural gene pilA.
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3

Graupner, Stefan, Verena Frey, Rozita Hashemi, Michael G. Lorenz, Gudrun Brandes e Wilfried Wackernagel. "Type IV Pilus Genes pilA andpilC of Pseudomonas stutzeri Are Required for Natural Genetic Transformation, and pilA Can Be Replaced by Corresponding Genes from Nontransformable Species". Journal of Bacteriology 182, n. 8 (15 aprile 2000): 2184–90. http://dx.doi.org/10.1128/jb.182.8.2184-2190.2000.

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Abstract (sommario):
ABSTRACT Pseudomonas stutzeri lives in terrestrial and aquatic habitats and is capable of natural genetic transformation. After transposon mutagenesis, transformation-deficient mutants were isolated from a P. stutzeri JM300 strain. In one of them a gene which coded for a protein with 75% amino acid sequence identity to PilC of Pseudomonas aeruginosa, an accessory protein for type IV pilus biogenesis, was inactivated. The presence of type IV pili was demonstrated by susceptibility to the type IV pilus-dependent phage PO4, by occurrence of twitching motility, and by electron microscopy. The pilC mutant had no pili and was defective in twitching motility. Further sequencing revealed that pilC is clustered in an operon with genes homologous to pilB andpilD of P. aeruginosa, which are also involved in pilus formation. Next to these genes but transcribed in the opposite orientation a pilA gene encoding a protein with high amino acid sequence identity to pilin, the structural component of type IV pili, was identified. Insertional inactivation of pilAabolished pilus formation, PO4 plating, twitching motility, and natural transformation. The amounts of 3H-labeled P. stutzeri DNA that were bound to competent parental cells and taken up were strongly reduced in the pilC andpilA mutants. Remarkably, the cloned pilA genes from nontransformable organisms like Dichelobacter nodosusand the PAK and PAO strains of P. aeruginosa fully restored pilus formation and transformability of the P. stutzeri pilA mutant (along with PO4 plating and twitching motility). It is concluded that the type IV pili of the soil bacterium P. stutzeri function in DNA uptake for transformation and that their role in this process is not confined to the species-specific pilin.
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4

Bertrand, Jacob J., Joyce T. West e Joanne N. Engel. "Genetic Analysis of the Regulation of Type IV Pilus Function by the Chp Chemosensory System of Pseudomonas aeruginosa". Journal of Bacteriology 192, n. 4 (11 dicembre 2009): 994–1010. http://dx.doi.org/10.1128/jb.01390-09.

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Abstract (sommario):
ABSTRACT The virulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of many virulence factors, including type IV pili, which are required for colonization of host tissues and for twitching motility. Type IV pilus function is controlled in part by the Chp chemosensory system, which includes a histidine kinase, ChpA, and two CheY-like response regulators, PilG and PilH. How the Chp components interface with the type IV pilus motor proteins PilB, PilT, and PilU is unknown. We present genetic evidence confirming the role of ChpA, PilG, and PilB in the regulation of pilus extension and the role of PilH and PilT in regulating pilus retraction. Using informative double and triple mutants, we show that (i) ChpA, PilG, and PilB function upstream of PilH, PilT, and PilU; (ii) that PilH enhances PilT function; and (iii) that PilT and PilB retain some activity in the absence of signaling input from components of the Chp system. By site-directed mutagenesis, we demonstrate that the histidine kinase domain of ChpA and the phosphoacceptor sites of both PilG and PilH are required for type IV pilus function, suggesting that they form a phosphorelay system important in the regulation of pilus extension and retraction. Finally, we present evidence suggesting that pilA transcription is regulated by intracellular PilA levels. We show that PilA is a negative regulator of pilA transcription in P. aeruginosa and that the Chp system functionally regulates pilA transcription by controlling PilA import and export.
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5

Villar, Maria T., Jennifer T. Helber, Becky Hood, Michael R. Schaefer e Rona L. Hirschberg. "Eikenella corrodens Phase Variation Involves a Posttranslational Event in Pilus Formation". Journal of Bacteriology 181, n. 14 (15 luglio 1999): 4154–60. http://dx.doi.org/10.1128/jb.181.14.4154-4160.1999.

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Abstract (sommario):
ABSTRACT The human pathogen Eikenella corrodens synthesizes type IV pili and exhibits a phase variation involving the irreversible transition from piliated to nonpiliated variants. On solid medium, piliated variants form small (S-phase), corroding colonies whereas nonpiliated variants form large (L-phase), noncorroding colonies. We are studying the molecular basis of this phase variation in the clinical isolate E. corrodens VA1. A genomic fragment encoding the major type IV pilin was cloned from the S-phase variant of strain VA1. Sequence analysis of the fragment revealed four tandemly arranged potential open reading frames (ORFs), designatedpilA1, pilA2, pilB, andhagA. Both pilA1 and pilA2 predict a type IV pilin. The protein predicted by pilB shares sequence identity with the Dichelobacter nodosus FimB fimbrial assembly protein. The protein predicted by hagAresembles a hemagglutinin. The region containing these four ORFs was designated the pilA locus. DNA hybridization and sequence analysis showed that the pilA locus of an L-phase variant of strain VA1 was identical to that of the S-phase variant. An abundantpilA1 transcript initiating upstream of pilA1and terminating at a predicted hairpin structure betweenpilA1 and pilA2 was detected by several assays, as was a less abundant read-through transcript encompassingpilA1, pilA2, and pilB. Transcription from the pilA locus was nearly indistinguishable between S- and L-phase variants. Electron microscopy and immunochemical analysis showed that S-phase variants synthesize, export, and assemble pilin into pili. In contrast, L-phase variants synthesize pilin but do not export and assemble it into pili. These data suggest that a posttranslational event, possibly involving an alteration in pilin export and assembly, is responsible for phase variation in E. corrodens.
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6

Li, Yinuo, Renate Lux, Andrew E. Pelling, James K. Gimzewski e Wenyuan Shi. "Analysis of type IV pilus and its associated motility in Myxococcus xanthus using an antibody reactive with native pilin and pili". Microbiology 151, n. 2 (1 febbraio 2005): 353–60. http://dx.doi.org/10.1099/mic.0.27614-0.

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Abstract (sommario):
Myxococcus xanthus possesses a social gliding motility that requires type IV pili (TFP). According to the current model, M. xanthus pili attach to an external substrate and retract, pulling the cell body forward along their long axis. By analogy with the situation in other bacteria employing TFP-dependent motility, M. xanthus pili have been assumed to be composed of pilin (PilA) subunits, but this has not previously been confirmed. The first 28 amino acids of the M. xanthus PilA protein share extensive homology with the N-terminal oligomerization domain of pilins in other bacterial species. To facilitate purification, the authors engineered a truncated form of M. xanthus PilA lacking the first 28 amino acids and purified this protein in soluble form. Polyclonal antibody generated against this protein was reactive with native pilin and pili. Using this antibody, it was confirmed that TFP of M. xanthus are indeed composed of PilA, and that TFP are located unipolarly and required for social gliding motility via retraction. Using tethering as well as motility assays, details of pili function in M. xanthus social motility were further examined.
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7

Scheuerpflug, Ina, Thomas Rudel, Roland Ryll, Jasmine Pandit e Thomas F. Meyer. "Roles of PilC and PilE Proteins in Pilus-Mediated Adherence of Neisseria gonorrhoeae and Neisseria meningitidis to Human Erythrocytes and Endothelial and Epithelial Cells". Infection and Immunity 67, n. 2 (1 febbraio 1999): 834–43. http://dx.doi.org/10.1128/iai.67.2.834-843.1999.

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Abstract (sommario):
ABSTRACT Unlike other type 4 pili, the neisserial pili consist of at least two distinct proteins, the highly variable major subunit PilE forming the pilus fiber and the tip-associated adhesin PilC. PilC protein purified either from gonococci or from Escherichia coliinteracted with different human epithelial cell lines, primary epithelial and endothelial cells. The binding of PilC protein efficiently prevented the attachment of piliated Neisseria gonorrhoeae and Neisseria meningitidis to these cell types. Fluorescent beads coated with pili prepared from piliated wild-type N. gonorrhoeae also adhered to these cells, in contrast to beads coated with pili prepared from a piliated PilC-deficient mutant. In the latter case, the binding of fluorescent beads was restored after pretreatment of the pilus-loaded beads with purified PilC. Piliated wild-type N. gonorrhoeae, the piliated PilC-deficient mutant, and N. gonorrhoeae pili assembled in Pseudomonas aeruginosa agglutinated human erythrocytes, while nonpiliated gonococci did not. Consistently, purified PilC did not agglutinate or bind to human erythrocytes, suggesting that N. gonorrhoeae PilE is responsible for pilus-mediated hemagglutination.
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8

Jelsbak, Lotte, e Dale Kaiser. "Regulating Pilin Expression Reveals a Threshold for S Motility in Myxococcus xanthus". Journal of Bacteriology 187, n. 6 (15 marzo 2005): 2105–12. http://dx.doi.org/10.1128/jb.187.6.2105-2112.2005.

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Abstract (sommario):
ABSTRACT An isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible promoter was constructed in Myxococcus xanthus. The single-copy pilA gene encodes pilin, the monomer unit of M. xanthus type IV pili. To vary the level of pilA expression, we cloned its promoter in front of the lac operator, and a plasmid containing the construct was inserted into the chromosome of a ΔpilA strain. Induction of pilin expression increased smoothly as the dose of IPTG added to the culture was increased. IPTG-induced pilin rescued S motility of the ΔpilA strain to wild-type levels. The rate of S-motile swarming was found to be proportional to the number of pili (shear-sensitive pilin) produced rather than to the level of total pilin. In fact, S motility was not rescued until the total level of pilin was more than 50% of the wild-type level. This observation implies that a threshold concentration of pilin must be exceeded before the shear-sensitive material (pili) is polymerized in M. xanthus.
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9

Bakaletz, Lauren O., Beth D. Baker, Joseph A. Jurcisek, Alistair Harrison, Laura A. Novotny, James E. Bookwalter, Rachna Mungur e Robert S. Munson. "Demonstration of Type IV Pilus Expression and a Twitching Phenotype by Haemophilus influenzae". Infection and Immunity 73, n. 3 (marzo 2005): 1635–43. http://dx.doi.org/10.1128/iai.73.3.1635-1643.2005.

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Abstract (sommario):
ABSTRACT Haemophilus influenzae is considered a nonmotile organism that expresses neither flagella nor type IV pili, although H. influenzae strain Rd possesses a cryptic pilus locus. We demonstrate here that the homologous gene cluster pilABCD in an otitis media isolate of nontypeable H. influenzae strain 86-028NP encodes a surface appendage that is highly similar, structurally and functionally, to the well-characterized subgroup of bacterial pili known as type IV pili. This gene cluster includes a gene (pilA) that likely encodes the major subunit of the heretofore uncharacterized H. influenzae-expressed type IV pilus, a gene with homology to a type IV prepilin peptidase (pilD) as well as two additional uncharacterized genes (pilB and pilC). A second gene cluster (comABCDEF) was also identified by homology to other pil or type II secretion system genes. When grown in chemically defined medium at an alkaline pH, strain 86-028NP produces approximately 7-nm-diameter structures that are near polar in location. Importantly, these organisms exhibit twitching motility. A mutation in the pilA gene abolishes both expression of the pilus structure and the twitching phenotype, whereas a mutant lacking ComE, a Pseudomonas PilQ homologue, produced large appendages that appeared to be membrane bound and terminated in a slightly bulbous tip. These latter structures often showed a regular pattern of areas of constriction and expansion. The recognition that H. influenzae possesses a mechanism for twitching motility will likely profoundly influence our understanding of H. influenzae-induced diseases of the respiratory tract and their sequelae.
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10

Macdonald, D. L., B. L. Pasloske e W. Paranchych. "Mutations in the fifth-position glutamate in Pseudomonas aeruginosa pilin affect the transmethylation of the N-terminal phenylalanine". Canadian Journal of Microbiology 39, n. 5 (1 maggio 1993): 500–505. http://dx.doi.org/10.1139/m93-071.

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Abstract (sommario):
The pili of Pseudomonas aeruginosa are composed of 15-kDa pilin monomers that are synthesized in the cytoplasm and assembled in the membrane. Processing occurs between the synthesis and assembly steps. The propilin is cleaved by a unique leader peptidase encoded by pilD, which is adjacent to the pilin structural gene pilA. This generates an N-terminal phenylalanine that is subsequently methylated by an as yet uncharacterized transmethylase. The pili of P. aeruginosa belong to the type IV class of pilins, which share a highly conserved N-terminal region 35 amino acids in length, containing a short leader of 6 or 7 amino acids. Two site-specific mutants in the N-terminal region of the mature pilin were constructed. Reestablishing the fifth-position glutamate in a four amino acid deletion mutant (amino acids 4–7) restored the leader peptidase cleavage but not the methylation. A mutation of the fifth-position glutamate to alanine decreased the degree of methylation of the N-terminal phenylalanine. Pili were not assembled by these mutants as assessed by electron microscopy and sensitivity to pilus-specific bacteriophage. Methylation may be required for recognition of the pilin by the assembly machinery and is not residue specific. The fifth-position glutamate appears to play an important role in transmethylase recognition of the pilin subunit.Key words: Pseudomonas aeruginosa, pilin, transmethylase.
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Più fonti

Tesi sul tema "Pili (Microbiology)"

1

Botten, James Alfons Desmond. "Role of sefD and sefR in the biogenesis of Salmonella enterica serovar Enteritidis SEF14 fimbriae". Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phb7512.pdf.

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2

Kennouche, Paul. "New insights into meningococcal pathogenesis : exploring the role of the major pilin PilE in the functions of type IV pili Mechanisms of meningococcal type IV pili multiple functions revealed by deep mutational scanning". Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=1972&f=12515.

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Abstract (sommario):
Les pili de type IV (PT4) sont des filaments micrométriques qui exercent de multiples fonctions à la surface de nombreux procaryotes. Chez Neisseria meningitidis, les PT4 sont des homopolymères de la piline majeure PilE. Leur implication dans l'agrégation interbactérienne et l'adhésion aux cellules humaines les rend centraux dans la virulence du méningocoque. Cependant, les mécanismes permettant aux PT4 d'exercer ces diverses fonctions restent trop élusifs. Durant ce doctorat, nous avons simultanément déterminé les régions de PilE impliquées dans l'assemblage des pili, l'auto-agrégation, l'adhésion aux cellules humaines et la compétence à la transformation en utilisant la technique de deep mutational scanning. L'analyse approfondie de cette carte fonctionnelle de la séquence de la piline offre de nouvelles perspectives sur les mécanismes de fonctionnement des PT4 : tout d'abord, le domaine hyperconservé 1 de PilE est impliqué dans la régulation de la balance entre la longueur et le nombre des pili ; par ailleurs, nous avons identifié un groupe d'acides aminés électropositifs autour de la lysine 140 requis pour l'agrégation ; enfin, nous montrons l'importance de l'extrémité distale des PT4 dans l'adhésion. En résumé, ces résultats sont en faveur d'un rôle direct de PilE dans l'agrégation et l'adhésion bactérienne et identifient les domaines spécifiquement impliqués dans ces fonctions. Ces travaux ouvrent aussi de nouvelles perspectives sur la pathogénicité de Neisseria meningitidis et pourraient participer au développement de nouvelles thérapies pour combattre les pathologies provoquées par le méningocoque
Type IV pili (TFP) are multifunctional micrometer-long filaments expressed at the surface of many prokaryotes. In Neisseria meningitidis, TFP are homopolymers of the major pilin PilE. They are crucial for virulence as they mediate interbacterial aggregation and adhesion to host cells although the mechanisms behind these functions remain unclear. During this doctoral work, we simultaneously determined the regions of PilE involved in pili display, auto-aggregation and adhesion to human cells by using deep mutational scanning. Mining of this extensive functional map of the pilin sequence provides new mechanistic insights: first, the hyperconserved 1-domain of PilE was found to be involved in the balance between pili length and number; moreover, we identified an electropositive cluster of residues centered around Lysine 140 necessary for aggregation; finally, we show the importance of the tip of TFP in adhesion. Overall, these results support a direct role of PilE in aggregation and adhesion to host cells and identify these specific functional domains. This doctoral work opens up new perspectives on the pathogenicity mechanisms of Neisseria meningitidis and could help design new therapies to fight meningococcal disease
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3

Paranjpye, Rohinee. "The role of a Vibrio vulnificus type IV pilin in pathogenesis and in persistence in oysters /". Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5372.

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4

Choi, Suk Ho. "Binding mechanism of K88ab pili produced by enterotoxigenic Escherichia coli". Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/74764.

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Abstract (sommario):
Binding of K88ab pili by brush border membrane and mucus from pig small intestine was characterized by inhibition assay and Western blot. In Western blot, K88ab pili were bound by two major brush border membrane polypeptides with molecular weight of 61,500 and 57,000 in addition to numerous minor polypeptides and a major mucus polypeptide with molecular weight of 27,500. The results from Western blot assays with periodate oxidized and carbamylated brush border membrane and inhibition assay with brush border membrane glycopeptide suggest that amino groups (rather than carbohydrate) present on the protein moiety are a part of the recognition site for K88ab pili of receptor polypeptides in brush border membrane. Differences were obtained in the binding patterns of K88ab pili when brush border membranes were prepared from small intestines obtained from 2-, 21-, and 42-day-old piglets as well as adult hogs. Binding of K88ab pili by mucus polypeptides was greater when prepared from small intestines obtained from 2-day-old piglets than from piglets of other ages and adult hogs. In inhibition assay, most fractions from sow milk and colostrum inhibited binding of K88ab pili. After gel filtration of colostral whey, fractions which contained IgG, IgA, and IgM produced the strongest inhibition of K88ab binding. Among fractions prepared from cow milk, casein and skim milk significantly inhibited binding of K88ab pili. In Western blot, αs1-casein, immunoglobulin chains, and MFGM polypeptides in sow milk and colostrum were shown to be able to bind K88ab pili. Additionally, αs1-casein was the major protein in bovine milk responsible for binding K88ab pili. In dot blot assay, IgG as well as brush border membrane could strongly bind K88ab pili. However, bovine αs1-casein showed only weak binding of K88ab pili. Binding of K88ab pili to these proteins and brush border membrane was inhibited by carbamylation and by addition of 100 mM D-galactosamine. The results suggest that the K88ab-binding proteins in milk and colostrum compete to bind K88ab pili with the receptors in the brush border membrane and that mechanisms involved in binding of K88ab pili by these proteins is similar to that by brush border membrane.
Ph. D.
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5

Karlsson, Katarina Flemmer. "Synthesis, conformational analysis, and biological evaluation of peptides from E. coli P pilus proteins". Lund : Organic Chemistry 2, Lund Institute of Technology, Lund University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/39777038.html.

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6

Charles-Orszag, Arthur. "Cellular and molecular mechanisms of human endothelial cell plasma membrane remodeling by Neisseria meningitidis". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB045/document.

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Abstract (sommario):
Neisseria meningitidis est une bactérie diderme qui colonise le nasopharynx humain de façon commensale. Occasionnellement, elle franchit la barrière nasopharyngée et accède à la circulation sanguine où elle peut provoquer un choc septique et/ou une méningite Le pouvoir pathogène de N. meningitidis est lié à sa capacité à interagir avec les cellules endothéliales humaines. Après avoir adhéré aux cellules grâce à des organelles filamenteux, les pili de type IV, les bactéries induisent une déformation de la membrane plasmique de la cellule hôte sous la forme de protrusions riches en actine ressemblant à des filopodes. Ces protrusions permettent aux bactéries de résister aux forces de cisaillements générées par le flux sanguin et de proliférer à la surface des cellules. Contrairement à de nombreuses autres bactéries pathogènes, cette déformation de la membrane plasmique ne nécessite pas de polymérisation d’actine. Cependant, les mécanismes cellulaires et moléculaires de cette déformation sont inconnus. Dans cette étude, nous montrons que lorsque des bactéries individuelles adhèrent à la cellule hôte, la membrane plasmique se déforme en adhérant le long des fibres de pili de type IV de façon similaire au mouillage d’un liquide sur un solide. Les pili de type IV agissent donc comme un échafaudage extracellulaire qui guide les protrusions de membrane plasmique indépendamment du cytosquelette d’actine. Nous montrons également que la capacité de la membrane plasmique à se déformer le long de structures adhésives nanométriques est une propriété intrinsèque des cellules endothéliales. Ces travaux décrivent le mécanisme d’une étape importante de la pathophysiologie de N. meningitidis et mettent en évidence des propriétés nouvelles de la membrane plasmique des cellules humaines qui pourraient être impliquées dans d’autres processus fondamentaux de biologie cellulaire
Neisseria meningitidis is a diderm bacterium that is naturally found in the human nasopharynx as a commensal. Occasionally, it can cross the mucosa and reach the underlying blood vessels where it enters the circulation. Once in the bloodstream, it can cause severe septic shock and/or meningitis. The ability of N. meningitidis to cause disease is tightly linked to its ability to interact with human endothelial cells. In particular, upon bacterial adhesion via filamentous organelles called type IV pili, bacteria remodel the host cell plasma membrane in the form of actin-rich, filopodia-like protrusions. These protrusions allow bacteria to resist blood flow-generated shear stress and proliferate on top of the host cells. Unlike many other bacterial pathogens, plasma membrane remodeling induced by N. meningitidis does not require actin polymerization. Yet, the cellular and molecular mechanisms of this process are unknown. Here, we show that upon adhesion of individual bacteria, the host cell plasma membrane deforms by adhering along type IV pili fibers in a wetting-like fashion. Therefore, type IV pili act as an extracellular scaffold that guide plasma membrane protrusions in an F-actin-independent manner. We further show that the ability of the plasma membrane to deform along nanoscale adhesive structures is an intrinsic property of endothelial cells. Therefore, this study uncovers the mechanism of a key step of N. meningitidis pathophysiology and reveals novel properties of human cell plasma membrane that could be at play in other fundamental cellular processes
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7

Kuehn, Joanna Sue Clegg Steven. "Dam methylation and putative fimbriae in Klebsiella pneumoniae". Iowa City : University of Iowa, 2009. http://ir.uiowa.edu/etd/391.

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8

Warren, Matthew J. "Analysis of the role of phosphorylcholine in Neisseria meningitidis /". [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19050.pdf.

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9

Choudhury, Devapriya. "Functional implications of macromolecular recognition : assembly of adhesive pili and enzyme substrate interactions /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5820-X.pdf.

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10

Wright, Denis Sebastian. "Cloning of the Bacteroides nodosus pilin gene and expression in Escherichia coli". Thesis, The University of Sydney, 1985. https://hdl.handle.net/2123/28530.

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Abstract (sommario):
The bacterium, Bagteroides nogosu , is the principal causative organism of footrot in sheep. a disease which causes major economic losses in Australia. Current footrot vaccines contain strains from each of the eight serogroups present in Australia. However, they are expensive and difficult to produce because B.nodosus an anaerobe has complex growth requirements and expression of the pilus, a major protective antigen is variable in liquid culture. The pilus (plural, pili) is composed essentially of one subunit protein called pilin and is the antigen which forms the basis for serotyping the organism. Purified pilus vaccines protect sheep against footrot challenge. It is therefore important to clone and characterise the genes reponsible for piliation in §.godosus. so that its regulation may be understood. With this knowledge, it should be possible to produce a cheap, reliable footrot vaccine based on genetically engineered strains that express high levels of pilus antigen. This work describes the cloning of the pilin gene from §.nodosu§ strain 215, which belongs to serogroup B. During the course of this project, three distinct b. nodosus loci have been cloned and expressed in Escherichia coli, an easily grown and well characterised bacterium. The first locus is represented by two clones pDWl and pDW3. carrying DNA inserts of 7.2 and 4.5 kilobases (kb). respectively. Analysis in maxicells shows that they both encode a protein which co—migrates with b. nodosus pilin and reacts weakly with pilus antiserum in Western blotting. It appears not to be the same pilin locus as that isolated from b. nodosus strain 198 (serogroup A: Anderson et al., 1984; Elleman et al., 1984). because the DNA shows no restriction homology with the strain 198 pilin clones. It is suggested that pDWl and pDW3 may encode an alternative pilin locus. The second locus is represented by pDW4, a clone carrying an insert of 10.2 kb. Western blotting shows that pDW4 encodes three proteins that are present in the pilus preparation used to raise antisera in rabbits. It does not encode pilin. These first two loci may encode proteins associated with pilus production, as the clones were detected using antibodies that had been raised against purified pili. The third locus is represented by pDWS and pDW6, carrying inserts of 10.0 and 5.6 kb repectively. These clones show strong expression of pilin in Western blotting experiments, and the DNA restriction maps exhibit homology with DNA from strain 198 pilin clones. Suggestions for further work, to determine the genes and conditions necessary for full pilus expression. are presented.
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Libri sul tema "Pili (Microbiology)"

1

1953-, Jarrell Kenneth F., a cura di. Pili and flagella: Current research and future trends. Norfolk, UK: Caister Academic Press, 2009.

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2

Holmgren, Anders. Structural studies of PapD, a chaperone protein involved in pili assembly, from E. coli. Uppsala: Sveriges Lantbruksuniversitet, 1993.

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3

Pili and flagella: Current research and future trends. Norfolk, UK: Caister Academic Press, 2009.

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4

1953-, Jarrell Kenneth F., a cura di. Pili and flagella: Current research and future trends. Norfolk, UK: Caister Academic Press, 2009.

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5

Barocchi, Michele Anne, e John L. Telford. Bacterial Pili: Structure, Synthesis and Role in Disease. CABI, 2014.

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6

Telford, John L., e Michèle Anne Barocchi. Bacterial Pili: Structure, Synthesis and Role in Disease. CABI, 2019.

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7

Per, Klemm, a cura di. Fimbriae: Adhesion, genetics, biogenesis, and vaccines. Boca Raton: CRC Press, 1994.

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8

Jann, Klaus. Bacterial Adhesins (Current Topics in Microbiology & Immunology, Volume 151). A cura di Klaus Jann. Springer, 1990.

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Capitoli di libri sul tema "Pili (Microbiology)"

1

Schmidt, M. A. "Synthetic Peptides: Prospects for a Pili (Fimbriae)-Based Synthetic Vaccine". In Current Topics in Microbiology and Immunology, 185–204. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-74703-8_10.

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2

Gelderblom, H., L. Beutin, D. Hadjiyiannis e H. Reupke. "Rapid Typing of Pili of Pathogenic Escherichia coli by Dispersive Immunoelectron Microscopy". In Rapid Methods and Automation in Microbiology and Immunology, 390–400. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-69943-6_49.

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3

Ranalli, G., P. Principi, M. Zucchi, F. da Borso, L. Catalano e C. Sorlini. "Pile Composting of Two-phase Centrifuged Olive Husks: Bioindicators of the Process". In Microbiology of Composting, 165–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-08724-4_14.

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4

Dhakal, B. K., J. M. Bower e M. A. Mulvey. "Pili, Fimbriae". In Encyclopedia of Microbiology, 470–89. Elsevier, 2009. http://dx.doi.org/10.1016/b978-012373944-5.00051-1.

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5

RCHAPMAN, M., M. AMULVEY e S. JHULTGREN. "Fimbriae and Pili". In Molecular Medical Microbiology, 177–97. Elsevier, 2002. http://dx.doi.org/10.1016/b978-012677530-3/50228-2.

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6

Volkan, Ender, Vasilios Kalas e Scott Hultgren. "Pili and Fimbriae of Gram-Negative Bacteria". In Molecular Medical Microbiology, 147–62. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-12-397169-2.00008-1.

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7

Barnhart, Michelle M., Joel D. Schilling, Fredrik Bäckhed, Agneta Richter Dahlfors, Staffan Normark e Scott J. Hultgren. "7 Host-pathogen interactions: Structure and function of pili". In Methods in Microbiology, 133–59. Elsevier, 2002. http://dx.doi.org/10.1016/s0580-9517(02)31008-0.

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8

Yan, Kuan, Xianming Zhao, Tong Huang, Wei Li, Yan Ren e Manzar Abbas. "Microbial Diversity in Sichuan Dark Tea during Pile-Fermentation". In Prime Archives in Microbiology. Vide Leaf, Hyderabad, 2021. http://dx.doi.org/10.37247/pamicr2ed.2.2021.20.

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