Siga este enlace para ver otros tipos de publicaciones sobre el tema: FIM3.
Artículos de revistas sobre el tema "FIM3"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "FIM3".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Hallander, Hans, Abdolreza Advani, Frances Alexander, Lennart Gustafsson, Margaretha Ljungman, Catherine Pratt, Ian Hall y Andrew R. Gorringe. "Antibody Responses to Bordetella pertussis Fim2 or Fim3 following Immunization with a Whole-Cell, Two-Component, or Five-Component Acellular Pertussis Vaccine and following Pertussis Disease in Children in Sweden in 1997 and 2007". Clinical and Vaccine Immunology 21, n.º 2 (4 de diciembre de 2013): 165–73. http://dx.doi.org/10.1128/cvi.00641-13.
Texto completoResumen
ABSTRACTBordetella pertussisfimbriae (Fim2 and Fim3) are components of a five-component acellular pertussis vaccine (diphtheria–tetanus–acellular pertussis vaccine [DTaP5]), and antibody responses to fimbriae have been associated with protection. We analyzed the IgG responses to individual Fim2 and Fim3 in sera remaining from a Swedish placebo-controlled efficacy trial that compared a whole-cell vaccine (diphtheria-tetanus-whole-cell pertussis vaccine [DTwP]), a two-component acellular pertussis vaccine (DTaP2), and DTaP5. One month following three doses of the Fim-containing vaccines (DTwP or DTaP5), anti-Fim2 geometric mean IgG concentrations were higher than those for anti-Fim3, with a greater anti-Fim2/anti-Fim3 IgG ratio elicited by DTaP5. We also determined the responses in vaccinated children following an episode of pertussis. Those who received DTaP5 showed a large rise in anti-Fim2 IgG, reflecting the predominant Fim2 serotype at the time. In contrast, those who received DTwP showed an equal rise in anti-Fim2 and anti-Fim3 IgG concentrations, indicating that DTwP may provide a more efficient priming effect for a Fim3 response following contact withB. pertussis. Anti-Fim2 and anti-Fim3 IgG concentrations were also determined in samples from two seroprevalence studies conducted in Sweden in 1997, when no pertussis vaccine was used and Fim2 isolates predominated, and in 2007, when either DTaP2 or DTaP3 without fimbriae was used and Fim3 isolates predominated. Very similar distributions of anti-Fim2 and anti-Fim3 IgG concentrations were obtained in 1997 and 2007, except that anti-Fim3 concentrations in 1997 were lower. This observation, together with the numbers of individuals with both anti-Fim2 and anti-Fim3 IgG concentrations, strongly suggests thatB. pertussisexpresses both Fim2 and Fim3 during infection.
2
Alexander, Frances, Mary Matheson, Norman K. Fry, Briony Labram y Andrew R. Gorringe. "Antibody Responses to Individual Bordetella pertussis Fimbrial Antigen Fim2 or Fim3 following Immunization with the Five-Component Acellular Pertussis Vaccine or to Pertussis Disease". Clinical and Vaccine Immunology 19, n.º 11 (5 de septiembre de 2012): 1776–83. http://dx.doi.org/10.1128/cvi.00355-12.
Texto completoResumen
ABSTRACTBordetella pertussisexpresses two serologically distinct fimbriae (Fim2 and Fim3) which are included in the Sanofi Pasteur 5-component acellular pertussis vaccine, and antibody responses to these antigens have been shown to be associated with protection. Studies to date have assessed the IgG response to this vaccine using a copurified mixture of Fim2 and Fim3, and the response to the individual antigens has not been characterized. We have purified separate Fim2 and Fim3 from strains that express either Fim2 or Fim3 and have used these antigens in an enzyme-linked immunosorbent assay (ELISA) to quantify IgG responses following immunization with 5-component acellular pertussis vaccine in 15-month-old, 4- to 6-year-old, and 11- to 18-year-old subjects. All individuals showed increases in Fim2 and Fim3 IgG concentrations following immunization, with 3-fold-greater Fim2 than Fim3 IgG concentrations seen in the younger two age groups. Fim2 IgG concentrations were 1.5-fold greater than Fim3 IgG concentrations in the 11- to 18-year-olds. We have also compared Fim2 and Fim3 IgG concentrations in individuals with prolonged cough who were diagnosed as having recent pertussis using a pertussis toxin (Ptx) IgG ELISA with individuals with prolonged cough but without elevated Ptx IgG concentrations. Individuals with evidence of recent pertussis had greater Fim3 IgG concentrations, consistent with the predominant serotype of isolates obtained in the United Kingdom. However, a surprising number of individuals had moderate Fim2 IgG concentrations despite very few isolates of that serotype obtained in the sampling period.
3
Saini, Supreet, Jeffrey A. Pearl y Christopher V. Rao. "Role of FimW, FimY, and FimZ in Regulating the Expression of Type I Fimbriae in Salmonella enterica Serovar Typhimurium". Journal of Bacteriology 191, n.º 9 (13 de febrero de 2009): 3003–10. http://dx.doi.org/10.1128/jb.01694-08.
Texto completoResumen
ABSTRACT Type I fimbriae in Salmonella enterica serovar Typhimurium are surface appendages that facilitate binding to eukaryotic cells. Expression of the fim gene cluster is known to be regulated by three proteins—FimW, FimY, and FimZ—and a tRNA encoded by fimU. In this work, we investigated how these proteins and tRNA coordinately regulate fim gene expression. Our results indicate that FimY and FimZ independently activate the P fimA promoter which controls the expression of the fim structural genes. FimY and FimZ were also found to strongly activate each other's expression and weakly activate their own expression. FimW was found to negatively regulate fim gene expression by repressing transcription from the P fimY promoter, independent of FimY or FimZ. Moreover, FimW and FimY interact within a negative feedback loop, as FimY was found to activate the P fimW promoter. In the case of fimU, the expression of this gene was not found to be regulated by FimW, FimY, or FimZ. We also explored the effect of fim gene expression on Salmonella pathogenicity island 1 (SPI1). Our results indicate that FimZ alone is able to enhance the expression of hilE, a known repressor of SPI1 gene expression. Based on our results, we were able to propose an integrated model for the fim gene circuit. As this model involves a combination of positive and negative feedback, we hypothesized that the response of this circuit may be bistable and thus a possible mechanism for phase variation. However, we found that the response was continuous and not bistable.
4
Gutiérrez-Ferman, J. L., L. Villarreal-Treviño, J. M. Ramírez-Aranda, A. Camacho-Ortiz, M. R. Ballesteros-Elizondo, M. R. Moreno-Juárez, S. Mendoza-Olazarán et al. "Emerging ofptxP3 lineage inBordetella pertussis strains circulating in a population in northeastern Mexico". Epidemiology and Infection 146, n.º 16 (23 de agosto de 2018): 2096–101. http://dx.doi.org/10.1017/s0950268818002303.
Texto completoResumen
AbstractWe determined the molecular epidemiology ofBordetella pertussisisolates to evaluate its potential impact on pertussis reemergence in a population of Mexico. Symptomatic and asymptomatic cases were included. Pertussis infection was confirmed by culture and real-time polymerase chain reaction (PCR). SelectedB. pertussisisolates were further analysed; i.e. clonality was analysed by pulsed-field gel electrophoresis (PFGE) andptxP-ptxA, prn,fim2 andfim3 typing was performed by PCR and sequencing. Out of 11 864 analysed samples, 687 (5.8%) were positive for pertussis, with 244 (36%) confirmed by both culture and PCR whereas 115 (17%) were positive only by culture and 328 (48%) were positive only by PCR. One predominant clone (clone A,n= 62/113; 55%) and three major subtypes (A1, A2 and A3) were identified by PFGE. All 113 selected isolates had the allelic combinationptxP3-ptxA1.The predominant clone A and the three major subtypes (A1, A2 and A3) corresponded to the emerging genotypesptxP3-ptxA1-prn2-fim2-1-fim3-2 andptxP3-ptxA1-prn2-fim2-1-fim3-1. In conclusion, the presence of an endemic clone and three predominant subtypes belonging to the genotypesptxP3-ptxA1-prn2-fim2-1-fim3-2andptxP3-ptxA1-prn2-fim2-1-fim3-1were detected. This finding supports the global spread/expansion reported for these outbreaks associated genotypes.
5
Mishra, Arunima, Asis Das, John O. Cisar y Hung Ton-That. "Sortase-Catalyzed Assembly of Distinct Heteromeric Fimbriae in Actinomyces naeslundii". Journal of Bacteriology 189, n.º 8 (2 de febrero de 2007): 3156–65. http://dx.doi.org/10.1128/jb.01952-06.
Texto completoResumen
ABSTRACT Two types of adhesive fimbriae are expressed by Actinomyces; however, the architecture and the mechanism of assembly of these structures remain poorly understood. In this study we characterized two fimbrial gene clusters present in the genome of Actinomyces naeslundii strain MG-1. By using immunoelectron microscopy and biochemical analysis, we showed that the fimQ-fimP-srtC1-fimR gene cluster encodes a fimbrial structure (designated type 1) that contains a major subunit, FimP, forming the shaft and a minor subunit, FimQ, located primarily at the tip. Similarly, the fimB-fimA-srtC2 gene cluster encodes a distinct fimbrial structure (designated type 2) composed of a shaft protein, FimA, and a tip protein, FimB. By using allelic exchange, we constructed an in-frame deletion mutant that lacks the SrtC2 sortase. This mutant produces abundant type 1 fimbriae and expresses the monomeric FimA and FimB proteins, but it does not assemble type 2 fimbriae. Thus, SrtC2 is a fimbria-specific sortase that is essential for assembly of the type 2 fimbriae. Together, our experiments pave the way for several lines of molecular investigation that are necessary to elucidate the fimbrial assembly pathways in Actinomyces and their function in the pathogenesis of different biofilm-related oral diseases.
6
Geuijen, Cecile A. W., Rob J. L. Willems, Peter Hoogerhout, Wouter C. Puijk, Rob H. Meloen y Frits R. Mooi. "Identification and Characterization of Heparin Binding Regions of the Fim2 Subunit of Bordetella pertussis". Infection and Immunity 66, n.º 5 (1 de mayo de 1998): 2256–63. http://dx.doi.org/10.1128/iai.66.5.2256-2263.1998.
Texto completoResumen
ABSTRACT Bordetella pertussis fimbriae bind to sulfated sugars such as heparin through the major subunit Fim2. The Fim2 subunit contains two regions, designated H1 and H2, which show sequence similarity with heparin binding regions of fibronectin, and the role of these regions in heparin binding was investigated with maltose binding protein (MBP)-Fim2 fusion proteins. Deletion derivatives of MBP-Fim2 showed that both regions are important for binding to heparin. The role of H2 in heparin binding was confirmed by site-directed mutagenesis in which basic amino acids were replaced by alanine. These studies revealed that Lys-186 and Lys-187 are important for heparin binding of MBP-Fim2, whereas Arg-179 is not required. Peptides derived from H1 and H2 (pepH1 and pepH2) also showed heparin binding activity. Using a series of peptides, in each of which a different basic amino acid was substituted for alanine, we demonstrated that the structural requirements for heparin binding differ significantly among pepH1 and pepH2 peptides. A Pepscan analysis of Fim2 revealed regions outside H1 and H2 which bind heparin and showed that not only basic amino acids but also tyrosines may be important for binding to sulfated sugars. A comparison of the heparin binding regions of Fim2 with homologous regions of Fim3 and FimX, two closely related but antigenically distinct fimbrial subunits, showed that basic amino acids and tyrosines are generally conserved. The major heparin binding regions identified in Fim2 are part of epitopes recognized by human antibodies, suggesting that the heparin binding regions are exposed at the fimbrial surface and are immunodominant. Since B. pertussis fimbriae show weak serological cross-reactivity, the differences in primary structure in the heparin binding regions of Fim2, Fim3, and FimX may affect antibody binding but not heparin binding, allowing the bacteria to evade antibody-mediated immunity by switching the fimbrial gene expressed.
7
Tinker, Juliette K. y Steven Clegg. "Characterization of FimY as a Coactivator of Type 1 Fimbrial Expression in Salmonella enterica Serovar Typhimurium". Infection and Immunity 68, n.º 6 (1 de junio de 2000): 3305–13. http://dx.doi.org/10.1128/iai.68.6.3305-3313.2000.
Texto completoResumen
ABSTRACT Type 1 fimbriae of Salmonella enterica serovar Typhimurium are surface appendages that carry adhesins specific for mannosylated host glycoconjugates. Regulation of the major fimbrial subunit is thought to be controlled by a number of ancillaryfim genes, including fimZ, fimY,fimW, and fimU. Previous studies using a FimZ mutant have indicated that this protein is necessary forfimA expression, and in vitro DNA binding assays determined that FimZ is a transcriptional activator that binds directly to thefimA promoter. To determine the role of FimY as a potential regulator of fimbrial expression, a fimY mutant of serovar Typhimurium was generated by allelic exchange. This mutant was found to be phenotypically nonfimbriate. No transcription from thefimA promoter was detected in a fimY mutant containing a fimA-lacZ reporter construct located on the chromosome. In addition, transcription from the cloned fimYpromoter was not detected in Escherichia coli unless both FimZ and FimY were present, indicating that these proteins also act as coactivators of fimY expression. Consistent with these results, there is no transcription from a fimY-lacZreporter construct within a serovar Typhimurium fimY orfimZ mutant. Studies using the fimY-lacZconstruct reveal that expression of this gene varies with environmental conditions in a manner similar to fimA expression. Extensive in vitro DNA binding assays using extracts from E. coli that overexpress FimY, as well as partially purified FimY, were unable to identify a specific interaction between FimY and thefimA or fimY promoter. The results indicate that FimY is a positive regulator of fimbrial expression and that this protein acts in cooperation with FimZ to regulate the expression ofSalmonella type 1 fimbrial appendages.
8
Bazhanova, I. G., M. V. Britsina, N. U. Mertsalova y M. N. Ozeretskovskaya. "Genetic variability of Bordetella pertussis and its role in vaccine prevention of pertussis". Journal of microbiology epidemiology immunobiology, n.º 4 (2 de septiembre de 2019): 98–105. http://dx.doi.org/10.36233/0372-9311-2019-4-98-105.
Texto completoResumen
In many countries of the world despite the extensively vaccination against pertussis has increased the incidence of the whooping cough in all age group of the population. The MLST, MLVA and CGH investigations revealed the differences in genotypes between the vaccine strains B.pertussis and the circulating isolates B.pertussis in consequence of adaptation of the bacterium B.pertussis to the immunized hosts. It is lead to waning immynity and outbreak of incidence of pertussis. The mutations in the genes encoding the major virulence factors, the allelic polimorfism and decreasing the genome size of B.pertussis strains are the basis of the B.pertussis adaptation to the immunized hosts and dependent on the type of the vaccine used for immunization Programme. In countries that use acellular pertussis vaccine for vaccination programme the dominant isolates genotypes are: ptxА1-ptxС2- ptxР3-prn2- tcfA2-1-fim3-2 и ptxА1- ptxС2- ptxР3-prnА2- tcfA2- fim2-1- fim3-1, and that use the cellular pertussis vaccine the dominant isolates genotypes are ptxА1-ptxС1- ptxР1-prn1- tcfA2- fim2-2 fim3-1 и ptxА1- ptxС1- ptxР1- prn2- tcfA2- fim2-1- fim3-1. The constant monitoring of the genotypes of isolates B.pertussis is necessary to reveal the dominant genotypes and include them in the national immunization programme in combination with vaccine strains B.pertussis.
9
Zeiner, Sarah A., Brett E. Dwyer y Steven Clegg. "FimY Does Not Interfere with FimZ-FimW Interaction during Type 1 Fimbria Production by Salmonella enterica Serovar Typhimurium". Infection and Immunity 81, n.º 12 (16 de septiembre de 2013): 4453–60. http://dx.doi.org/10.1128/iai.00795-13.
Texto completoResumen
ABSTRACTThe production of type 1 fimbriae inSalmonella entericaserovar Typhimurium is controlled, in part, by three proteins, FimZ, FimY, and FimW. Amino acid sequence analysis indicates that FimZ belongs to the family of bacterial response regulators of two-component systems. In these studies, we have demonstrated that introducing a mutation mimicking phosphorylation of FimZ is necessary for activation of its target gene,fimA. In addition, the interaction of FimZ with FimW, a repressor offimAexpression, occurs only when FimZ is phosphorylated. Consequently, the negative regulatory effect of FimW is most likely due to downmodulation of the active FimZ protein. FimY does not appear to function as a response regulator, and its activity can be lost by mimicking the phosphorylation of FimY. Overproduction of FimY cannot alleviate the nonfimbriate phenotype in a FimZ mutant, whereas high levels of FimZ can overcome the nonfimbriate phenotype of a FimY mutant. It appears that FimY acts upstream of FimZ to activatefimAexpression.
10
Vaughan, Thomas E., Catherine B. Pratt, Katie Sealey, Andrew Preston, Norman K. Fry y Andrew R. Gorringe. "Plasticity of fimbrial genotype and serotype within populations of Bordetella pertussis: analysis by paired flow cytometry and genome sequencing". Microbiology 160, n.º 9 (1 de septiembre de 2014): 2030–44. http://dx.doi.org/10.1099/mic.0.079251-0.
Texto completoResumen
The fimbriae of Bordetella pertussis are required for colonization of the human respiratory tract. Two serologically distinct fimbrial subunits, Fim2 and Fim3, considered important vaccine components for many years, are included in the Sanofi Pasteur 5-component acellular pertussis vaccine, and the World Health Organization recommends the inclusion of strains expressing both fimbrial serotypes in whole-cell pertussis vaccines. Each of the fimbrial major subunit genes, fim2, fim3, and fimX, has a promoter poly(C) tract upstream of its −10 box. Such monotonic DNA elements are susceptible to changes in length via slipped-strand mispairing in vitro and in vivo, which potentially causes on/off switching of genes at every cell division. Here, we have described intra-culture variability in poly(C) tract lengths and the resulting fimbrial phenotypes in 22 recent UK B. pertussis isolates. Owing to the highly plastic nature of fimbrial promoters, we used the same cultures for both genome sequencing and flow cytometry. Individual cultures of B. pertussis contained multiple fimbrial serotypes and multiple different fimbrial promoter poly(C) tract lengths, which supports earlier serological evidence that B. pertussis expresses both serotypes during infection.
11
Borisova, Olga, Svetlana Yu Kombarova, Nelli S. Zakharova, Marjolein van Gent, Vladimir A. Aleshkin, Isabella Mazurova y Frits R. Mooi. "Antigenic Divergence between Bordetella pertussis Clinical Isolates from Moscow, Russia, and Vaccine Strains". Clinical and Vaccine Immunology 14, n.º 3 (3 de enero de 2007): 234–38. http://dx.doi.org/10.1128/cvi.00294-06.
Texto completoResumen
ABSTRACT We analyzed temporal changes in the frequencies of the ptxA, prn, fim2, and fim3 alleles in Bordetella pertussis strains isolated from pertussis patients in Moscow, Russia, from 1948 to 2004. The three strains used for the whole-cell vaccine harbored the alleles ptxA2, ptxA4, prn1, fim2-1, and fim3A. Vaccine-type alleles of ptxA (ptxA2 and ptxA4) were characteristic for all prevaccination strains and for 96% of the strains isolated in the 1960s and 1970s. At the beginning of the 1970s, ptxA2 and ptxA4 were replaced by the ptxA1 allele. In the 1980s and to the present, strains with ptxA1 were predominant in the B. pertussis population. All prevaccination strains harbored the prn1 allele, which corresponds to the vaccine-type allele. In subsequent years, the proportion of strains with the prn1 allele decreased and the proportion of prn3 and prn2 strains increased. From 2002 to 2004 strains with prn2 or prn3 were predominant in the B. pertussis population. The vaccine-type alleles fim2-1 and fim3A were found in all prevaccination strains and in 92% of the strains isolated from 1960 to 1989. The fim2-2 and fim3B alleles were first observed at the beginning of the 1980s. In subsequent years, these strains became predominant. Together with waning immunity, the antigenic divergence between vaccine strains and clinical isolates observed in the Moscow area may explain the persistence of pertussis, despite the high rates of vaccine coverage. The results demonstrate that the selection of B. pertussis strains for vaccine manufacturing must be based on a thorough study of the B. pertussis population.
12
Pierce, Deanne L., So-ichiro Nishiyama, Shuang Liang, Min Wang, Martha Triantafilou, Kathy Triantafilou, Fuminobu Yoshimura, Donald R. Demuth y George Hajishengallis. "Host Adhesive Activities and Virulence of Novel Fimbrial Proteins of Porphyromonas gingivalis". Infection and Immunity 77, n.º 8 (8 de junio de 2009): 3294–301. http://dx.doi.org/10.1128/iai.00262-09.
Texto completoResumen
ABSTRACT The fimbriae of Porphyromonas gingivalis mediate critical roles in host colonization and evasion of innate defenses and comprise polymerized fimbrilin (FimA) associated with quantitatively minor accessory proteins (FimCDE) of unknown function. We now show that P. gingivalis fimbriae lacking FimCDE fail to interact with the CXC-chemokine receptor 4 (CXCR4), and bacteria expressing FimCDE-deficient fimbriae cannot exploit CXCR4 in vivo for promoting their persistence, as the wild-type organism does. Consistent with these loss-of-function experiments, purified FimC and FimD (but not FimE) were shown to interact with CXCR4. However, significantly stronger binding was observed when a combination of all three proteins was allowed to interact with CXCR4. In addition, FimC and FimD bound to fibronectin and type 1 collagen, whereas FimE failed to interact with these matrix proteins. These data and the fact that FimE is required for the association of FimCDE with P. gingivalis fimbriae suggest that FimE may recruit FimC and FimD into a functional complex, rather than directly binding host proteins. Consistent with this notion, FimE was shown to bind both FimC and FimD. In summary, the FimCDE components cooperate and impart critical adhesive and virulence properties to P. gingivalis fimbriae.
13
McFarland, Kirsty A., Sacha Lucchini, Jay C. D. Hinton y Charles J. Dorman. "The Leucine-Responsive Regulatory Protein, Lrp, Activates Transcription of the fim Operon in Salmonella enterica Serovar Typhimurium via the fimZ Regulatory Gene". Journal of Bacteriology 190, n.º 2 (2 de noviembre de 2007): 602–12. http://dx.doi.org/10.1128/jb.01388-07.
Texto completoResumen
ABSTRACT The fim operon of Salmonella enterica serovar Typhimurium encodes type 1 fimbriae. The expression of fim is controlled in response to environmental signals through a complex regulatory cascade involving the proteins FimW, FimY, and FimZ and a genetic locus, fimU, that encodes a rare arginine tRNA. We discovered that a knockout mutation in lrp, the gene that codes for the leucine-responsive regulatory protein (Lrp), inhibited fim transcription. The loss of fim gene expression was accompanied by a corresponding loss of the mannose-sensitive hemagglutination that is a characteristic of type 1 fimbriae. Normal type 1 fimbrial expression was restored following the introduction into the knockout mutant of a plasmid carrying a functional copy of the lrp gene. Electrophoretic mobility shift analysis revealed no interactions between purified Lrp protein and the regulatory region of the fimA, fimU, or fimW gene. Instead, Lrp produced protein-DNA complexes with the regulatory region of the fimZ gene, and the nature of these complexes was leucine sensitive. DNase I footprinting showed that Lrp binds within a region between −65 and −170 with respect to the fimZ transcription start site, consistent with the binding and wrapping of the DNA in this upstream region. Ectopic expression of the fimZ gene from an inducible promoter caused Lrp-independent type 1 fimbriation in serovar Typhimurium. These data show that Lrp makes a positive contribution to fim gene expression through direct interaction with the fimZ promoter region, possibly by antagonizing the binding of the H-NS global repressor protein.
14
Mattoo, Seema, Jeff F. Miller y Peggy A. Cotter. "Role of Bordetella bronchisepticaFimbriae in Tracheal Colonization and Development of a Humoral Immune Response". Infection and Immunity 68, n.º 4 (1 de abril de 2000): 2024–33. http://dx.doi.org/10.1128/iai.68.4.2024-2033.2000.
Texto completoResumen
ABSTRACT Fimbriae are filamentous, cell surface structures which have been proposed to mediate attachment of Bordetella species to respiratory epithelium. Bordetella bronchiseptica has four known fimbrial genes: fim2, fim3,fimX, and fimA. While these genes are unlinked on the chromosome, their protein products are assembled and secreted by a single apparatus encoded by the fimBCD locus. ThefimBCD locus is embedded within the fha operon, whose genes encode another putative adhesin, filamentous hemagglutinin (FHA). We have constructed a Fim− B. bronchiseptica strain, RB63, by introducing an in-frame deletion extending from fimB through fimD. Western blot analysis showed that RB63 is unable to synthesize fimbriae but is unaffected for FHA expression. Using this mutant, we assessed the role of fimbriae in pathogenesis in vitro and in vivo in natural animal hosts. Although RB63 was not significantly defective in its ability to adhere to various tissue culture cell lines, including human laryngeal HEp-2 cells, it was considerably altered in its ability to cause respiratory tract infections in rats. The number of ΔfimBCD bacteria recovered from the rat trachea at 10 days postinoculation was significantly decreased compared to that of wild-type B. bronchiseptica and was below the limit of detection at 30 and 60 days postinoculation. The number of bacteria recovered from the nasal cavity and larynx was not significantly different between RB63 and the wild-type strain at any time point. The ability of fimbriae to mediate initial attachment to tracheal tissue was tested in an intratracheal inoculation assay. Significantly fewer RB63 than wild-type bacteria were recovered from the tracheas at 24 h after intratracheal inoculation. These results demonstrate that fimbriae are involved in enhancing the ability of B. bronchiseptica to establish tracheal colonization and are essential for persistent colonization at this site. Interestingly, anti-Bordetella serum immunoglobulin M (IgM) levels were significantly lower in animals infected with RB63 than in animals infected with wild-type B. bronchiseptica at 10 days postinoculation. Even at 30 days postinoculation, RB63-infected animals had lower serum anti-Bordetella antibody titers in general. This disparity in antibody profiles suggests that fimbriae are also important for the induction of a humoral immune response.
15
Tinker, Juliette K., Lisa S. Hancox y Steven Clegg. "FimW Is a Negative Regulator Affecting Type 1 Fimbrial Expression in Salmonella enterica Serovar Typhimurium". Journal of Bacteriology 183, n.º 2 (15 de enero de 2001): 435–42. http://dx.doi.org/10.1128/jb.183.2.435-442.2001.
Texto completoResumen
ABSTRACT Type 1 fimbriae are proteinaceous surface appendages that carry adhesins specific for mannosylated glycoproteins. These fimbriae are found on most members of the family Enterobacteriaceae and are known to facilitate binding to a variety of eukaryotic cells, including those found on the mucosal surfaces of the alimentary tract. We have shown that the regulation of type 1 fimbrial expression in Salmonella enterica serovar Typhimurium is controlled, in part, by the products of four genes found within the fimgene cluster: fimZ, fimY, fimW, andfimU. To better understand the specific role of FimW in fimbrial expression, a mutation was constructed in this gene by the insertion of a kanamycin resistance DNA cassette into the chromosome. The resulting fimW mutation was characterized by mannose-sensitive hemagglutination and agglutination with fimbria-specific antiserum. Assays suggested that this mutant was more strongly fimbriate than the parental strain, exhibiting a four- to eightfold increase in fimbrial production. The fimWmutation was introduced into a second strain of Salmonella enterica serovar Typhimurium, and this mutant was also found to be strongly fimbriate compared to the parental strain. Consistent with the role of this protein as a negative regulator, fimA-lacZexpression in serovar Typhimurium, as well as in Escherichia coli, was increased twofold in the absence of functional FimW. Primer extension analysis determined that fimWtranscription is initiated from its own promoter 31 bp upstream of the translation start site. Analysis using a fimW-lacZ reporter indicated that fimW expression in serovar Typhimurium was increased under conditions that select for poorly fimbriate bacteria and low fimA expression. FimW also appears to act as an autoregulator, since expression from the fimW-lacZ reporter was increased in a fimW mutant. FimW was partially purified by fusion with the E. coli maltose-binding protein. Use of this FimW protein extract, as well as others, in DNA-binding assays was unable to identify a specific binding site for FimW in thefimA, fimZ, fimY, orfimW promoter regions. To analyze protein-protein interactions, FimW was expressed in a LexA-based two-hybrid system inE. coli. A significant interaction between FimW and the DNA-binding activator protein, FimZ, was detected using this system. These results indicate that FimW is a negative regulator of serovar Typhimurium type 1 fimbrial expression and may function by interfering with FimZ-mediated activation of fimA expression.
16
Zhang, Juansheng, Diqiang Zhang, Xiaoqiang Wang, Xiaoguang Wei y Hao Li. "Macrolide susceptibility and molecular characteristics of Bordetella pertussis". Journal of International Medical Research 50, n.º 2 (febrero de 2022): 030006052210787. http://dx.doi.org/10.1177/03000605221078782.
Texto completoResumen
Objective To analyse macrolide resistance and molecular characteristics of Bordetella pertussis clinical isolates from western China, and to explore the relationship between macrolide-resistance and genotypes. Methods Susceptibilities of B. pertussis clinical isolates to erythromycin, azithromycin and clarithromycin were determined by epsilometer test (E-test). Isolated strains were sequenced to ascertain the presence of the 23S rRNA gene A2047G mutation. Strains were typed using multilocus antigen sequence typing, multilocus variable-number tandem-repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). Results Of 58 B. pertussis strains isolated in this study, 46 were macrolide-resistant and 12 were macrolide sensitive. All macrolide-resistant strains carried the A2047G mutation and were the prn1/ ptxP1/ ptxA1/ fim3-1/ fim2-1 genotype; the MLVA types were MT195 (19/58), MT55 (13/58) and MT104 (14/58), and the PFGE profiles were classified into BpSR23 (17/58) and BpFINR9 (29/58) types. None of the macrolide-sensitive strains carried the A2047G mutation; genotypes were ( prn9 or prn2)/ ptxP3/ ptxA1/ fim3-1/ fim2-1, and all were MT27. PFGE profiles differed from the macrolide-resistant strains. Conclusions B. pertussis clinical isolates from western China were severely resistant to macrolides. Genotypes differed between macrolide-resistant and macrolide-sensitive strains, and there may be a correlation between acquisition of macrolide resistance and changes in specific molecular types.
17
Cuzzoni, A., P. Pedroni, B. Riboli, G. Grandi y F. de Ferra. "Nucleotide sequence of the fim3 gene fromBordetella pertussisand homology to fim2 and fimX gene products". Nucleic Acids Research 18, n.º 6 (1990): 1640. http://dx.doi.org/10.1093/nar/18.6.1640.
Texto completo
18
Savelkoul, P. H., D. P. de Kerf, R. J. Willems, F. R. Mooi, B. A. van der Zeijst y W. Gaastra. "Characterization of the fim2 and fim3 fimbrial subunit genes of Bordetella bronchiseptica: roles of Fim2 and Fim3 fimbriae and flagella in adhesion." Infection and immunity 64, n.º 12 (1996): 5098–105. http://dx.doi.org/10.1128/iai.64.12.5098-5105.1996.
Texto completo
19
Xie, Yi, Yufeng Yao, Vitaliy Kolisnychenko, Ching-Hao Teng y Kwang Sik Kim. "HbiF Regulates Type 1 Fimbriation Independently of FimB and FimE". Infection and Immunity 74, n.º 7 (julio de 2006): 4039–47. http://dx.doi.org/10.1128/iai.02058-05.
Texto completoResumen
ABSTRACT Type 1 fimbriae have been suggested to play a role in the pathogenesis of extraintestinal Escherichia coli infection. Type 1 fimbriation in E. coli is phase variable and known to be dependent upon FimB and FimE, the two recombinases that invert the molecular switch fimS and control the expression of the downstream fim operon. Here we showed that HbiF, a novel site-specific recombinase, inverted fimS independently of FimB and FimE. HbiF-mediated fimS inversion appeared to be predominantly switching from “off” (termed OFF) to “on” (termed ON) orientation. This is different from the fimS inversion mediated by either FimB (bidirectional ON to OFF and OFF to ON) or FimE (unidirectional ON to OFF). Constitutive expression of the hbiF gene in E. coli resulted in a fimS-locked-ON phenotype, which resulted in the pathogenic E. coli K1 strain being incapable of inducing a high degree of bacteremia in neonatal rats. Discovery of HbiF-mediated OFF-to-ON fimS switching provides a new opportunity to develop a strategy for the prevention and therapy of extraintestinal E. coli infection including bacteremia and meningitis.
20
Schwan, William R., Satoshi Shibata, Shin-Ichi Aizawa y Alan J. Wolfe. "The Two-Component Response Regulator RcsB Regulates Type 1 Piliation in Escherichia coli". Journal of Bacteriology 189, n.º 19 (20 de julio de 2007): 7159–63. http://dx.doi.org/10.1128/jb.00705-07.
Texto completoResumen
ABSTRACT The ability of Escherichia coli cells to produce type 1 pili depends upon the orientation of the fimA promoter. The orientation depends upon the ratios of the FimB and FimE recombinases. Here, we report that the two-component response regulator RcsB influences the piliation state by controlling fimB and fimE transcription.
21
Yin, Lizi, Yuyun Dai, Han Chen, Xuewen He, Ping Ouyang, Xiaoli Huang, Xiangang Sun et al. "Cinnamaldehyde Resist Salmonella Typhimurium Adhesion by Inhibiting Type I Fimbriae". Molecules 27, n.º 22 (10 de noviembre de 2022): 7753. http://dx.doi.org/10.3390/molecules27227753.
Texto completoResumen
Salmonella Typhimurium (S. Typhimurium), a common foodborne pathogen, severely harms the public and food security. Type I fimbriae (T1F) of S. Typhimurium, plays a crucial role in the pathogenic processes; it mediates the adhesion of bacteria to the mannose receptor on the host cell, assists the bacteria to invade the host cell, and triggers an inflammatory response. Cinnamaldehyde is the main ingredient in cinnamon essential oil. In this study, cinnamaldehyde was demonstrated to inhibit the expression of T1F by hemagglutination inhibition test, transmission electron microscopy, and biofilms. The mechanism of cinnamaldehyde action was studied by proteomics technology, PCR and Western blotting. The results showed that cinnamaldehyde can inhibit T1F in S. typhimurium without the growth of bacteria, by regulating the level of expression and transcription of fimA, fimZ, fimY, fimH and fimW. Proteomics results showed that cinnamaldehyde downregulated the subunits and regulators of T1F. In addition, the invasion assays proved that cinnamaldehyde can indeed reduce the ability of S. typhimurium to adhere to cells. The results of animal experiments showed that the colonization in the intestinal tract and the expression levels of inflammatory cytokine were significantly decreased, and the intestinal mucosal immune factors MUC1 and MUC2 were increased under cinnamaldehyde treatment. Therefore, cinnamaldehyde may be a potential drug to target T1F to treat Salmonella infections.
22
Han, Xiaoyan, Ruth M. Kennan, Dane Parker, John K. Davies y Julian I. Rood. "Type IV Fimbrial Biogenesis Is Required for Protease Secretion and Natural Transformation in Dichelobacter nodosus". Journal of Bacteriology 189, n.º 14 (18 de mayo de 2007): 5022–33. http://dx.doi.org/10.1128/jb.00138-07.
Texto completoResumen
ABSTRACT The objective of this study was to develop an understanding of the molecular mechanisms by which type IV fimbrial biogenesis, natural transformation, and protease secretion are linked in the ovine foot rot pathogen, Dichelobacter nodosus. We have shown that like the D. nodosus fimbrial subunit FimA, the pilin-like protein PilE and the FimN, FimO, and FimP proteins, which are homologs of PilB, PilC, and PilD from Pseudomonas aeruginosa, are essential for fimbrial biogenesis and natural transformation, indicating that transformation requires an intact type IV fimbrial apparatus. The results also showed that extracellular protease secretion in the fimN, fimO, fimP, and pilE mutants was significantly reduced, which represents the first time that PilB, PilC, and PilE homologs have been shown to be required for the secretion of unrelated extracellular proteins in a type IV fimbriate bacterium. Quantitative real-time PCR analysis of the three extracellular protease genes aprV2, aprV5, and bprV showed that the effects on protease secretion were not mediated at the transcriptional level. Bioinformatic analysis did not identify a classical type II secretion system, and the putative fimbrial biogenesis gene pilQ was the only outer membrane secretin gene identified. Based on these results, it is postulated that in D. nodosus, protease secretion occurs by a type II secretion-related process that directly involves components of the type IV fimbrial biogenesis machinery, which represents the only type II secretion system encoded by the small genome of this highly evolved pathogen.
23
Nishikawa, Kiyoshi y Margaret J. Duncan. "Histidine Kinase-Mediated Production and Autoassembly of Porphyromonas gingivalis Fimbriae". Journal of Bacteriology 192, n.º 7 (29 de enero de 2010): 1975–87. http://dx.doi.org/10.1128/jb.01474-09.
Texto completoResumen
ABSTRACT Porphyromonas gingivalis, a Gram-negative oral anaerobe, is strongly associated with chronic adult periodontitis, and it utilizes FimA fimbriae to persistently colonize and evade host defenses in the periodontal crevice. The FimA-related gene cluster (the fim gene cluster) is positively regulated by the FimS-FimR two-component system. In this study, comparative analyses between fimbriate type strain ATCC 33277 and fimbria-deficient strain W83 revealed differences in their fimS loci, which encode FimS histidine kinase. Using a reciprocal gene exchange system, we established that FimS from W83 is malfunctional. Complementation analysis with chimeric fimS constructs revealed that W83 FimS has a defective kinase domain due to a truncated conserved G3 box motif that provides an ATP-binding pocket. The introduction of the functional fimS from 33277 restored the production, but not polymerization, of endogenous FimA subunits in W83. Further analyses with a fimA-exchanged W83 isogenic strain showed that even the fimbria-deficient W83 retains the ability to polymerize FimA from 33277, indicating the assembly of mature FimA by a primary structure-dependent mechanism. It also was shown that the substantial expression of 33277-type FimA fimbriae in the W83 derivative requires the introduction and expression of the functional 33277 fimS. These findings indicate that FimSR is the unique and universal regulatory system that activates the fim gene cluster in a fimA genotype-independent manner.
24
Schwan, William R., Jeffrey L. Lee, Farrah A. Lenard, Brian T. Matthews y Michael T. Beck. "Osmolarity and pH Growth Conditions Regulate fim Gene Transcription and Type 1 Pilus Expression in Uropathogenic Escherichia coli". Infection and Immunity 70, n.º 3 (marzo de 2002): 1391–402. http://dx.doi.org/10.1128/iai.70.3.1391-1402.2002.
Texto completoResumen
ABSTRACT A comparative study was performed to determine the effects of pH, osmolarity, and human urine on the transcription of several fim genes, as well as the overall expression of type 1 pili. Several fim-lacZYA fusions were constructed on single-copy plasmids to test a range of pHs and a range of osmolarities. Growth in acidic medium slightly reduced expression from all of the fim promoters (fimA, fimB, and fimE). Increased osmolarity in neutral-pH medium repressed fimA and fimB transcription by approximately 50% when 400 mM NaCl was used and nearly threefold when 800 mM NaCl was used, whereas fimE transcription rose slightly as the osmolarity increased. This effect was more pronounced in high-osmolarity acidic media; fimB and fimA expression decreased fivefold in growth media containing 800 mM NaCl compared to expression in growth media without added NaCl. Moreover, fimE expression doubled under the same high-osmolarity conditions compared to expression in a low-osmolarity acidic environment. When a fimB-lacZ or fimE-lacZ fusion was inserted into the chromosome of strain AAEC189, fimE expression changed slightly as the osmolarity increased, but fimB expression decreased by 50% in a low-pH high-osmolarity environment. When strain AAEC189 with either a plasmid-borne fimB-lacZ fusion or a plasmid-borne fimE-lacZ fusion was grown in human urine, similar changes in the levels of fimB and fimE expression were observed. Limiting-dilution reverse transcription-PCR confirmed that these changes in fim expression occurred in clinical isolates of uropathogenic Escherichia coli grown in media with different pHs and different osmolarities. Furthermore, the invertible switch region in uropathogenic strain NU149 shifted from favoring the phase-on position in a neutral-pH low-osmolarity environment to favoring the phase-off position in a low-pH high-osmolarity environment. Results obtained with an ompR mutant strain demonstrated that fimB expression was derepressed and that OmpR may neutralize repression by an acid response regulator of fimE expression in a low-pH environment. In addition, H-NS was verified to be important in regulation of fimB, but it had only a slight effect on fimE under the specific pH and osmotic growth conditions tested. Enzyme immunoassays with anti-type 1 pilus antibody and hemagglutination assays showed that fewer type 1 pili were detected with cells in a low-pH high-osmolarity environment. Together, these observations demonstrate that a combination of low pH and high osmolarity regulates the transcription of fim genes, which favors a shift in the invertible element to the phase-off orientation and a loss of type 1 pilus expression. Taken together, our data suggest that the environmental cues that we tested may regulate expression of type 1 pili in specific in vivo niches, such as murine kidneys and possibly human kidneys.
25
Zeiner, Sarah A., Brett E. Dwyer y Steven Clegg. "FimA, FimF, and FimH Are Necessary for Assembly of Type 1 Fimbriae on Salmonella enterica Serovar Typhimurium". Infection and Immunity 80, n.º 9 (9 de julio de 2012): 3289–96. http://dx.doi.org/10.1128/iai.00331-12.
Texto completoResumen
ABSTRACTSalmonella entericaserovar Typhimurium is a Gram-negative member of the familyEnterobacteriaceaeand is a common cause of bacterial food poisoning in humans. The fimbrial appendages are found on the surface of many enteric bacteria and enable the bacteria to bind to eukaryotic cells.S. Typhimurium type 1 fimbriae are characterized by mannose-sensitive hemagglutination and are assembled via the chaperone/usher pathway.S. Typhimurium type 1 fimbrial proteins are encoded by thefimgene cluster (fimAICDHFZYW), withfimAICDHFexpressed as a single transcriptional unit. The structural components of the fimbriae are FimA (major subunit), FimI, FimH (adhesin), and FimF (adaptor). In order to determine which components are required for fimbrial formation inS. Typhimurium, mutations infimA,fimI,fimH, andfimFwere constructed and examined for their ability to produce surface-assembled fimbriae.S. Typhimurium SL1344ΔfimA, -ΔfimH, and -ΔfimFmutants were unable to assemble fimbriae, indicating that these genes are necessary for fimbrial production inS. Typhimurium. However, SL1344ΔfimIwas able to assemble fimbriae. InEscherichia colitype 1 and Pap fimbriae, at least two adaptors are expressed in addition to the adhesins. However,E. colitype 1 and Pap fimbriae have been reported to be able to assemble fimbriae in the absence of these proteins. These results suggest differences between theS. Typhimurium type 1 fimbrial system and theE. colitype 1 and Pap fimbrial systems.
26
Boyd, E. Fidelma y Daniel L. Hartl. "Analysis of the Type 1 Pilin Gene Clusterfim in Salmonella: Its Distinct Evolutionary Histories in the 5′ and 3′ Regions". Journal of Bacteriology 181, n.º 4 (15 de febrero de 1999): 1301–8. http://dx.doi.org/10.1128/jb.181.4.1301-1308.1999.
Texto completoResumen
ABSTRACT The type 1 pilin encoded by fim is present in bothEscherichia coli and Salmonella natural isolates, but several lines of evidence indicate that similarities at the fim locus may be an example of independent acquisition rather than common ancestry. For example, the fim gene cluster is found at different chromosomal locations and with distinct gene orders in these closely related species. In this work we examined the fim gene cluster of Salmonella, the genes of which show high nucleotide sequence divergence from their E. coli counterparts, as well as a different G+C content and codon usage. DNA hybridization analysis revealed that, among the salmonellae, the fim gene cluster is present in all isolates of S. enterica but is absent from S. bongori. Molecular phylogenetic analyses of the fimA and fimIgenes yield an estimate of phylogeny that is in satisfactory congruence with housekeeping and other virulence genes examined in this species. In contrast, phylogenetic analyses of the fimZ,fimY, and fimW genes indicate that horizontal transfer of this region has occurred more than once. There is also size variation in the fimZ, fimY, andfimW intergenic regions in the 3′ region, and these genes are absent in isolate S2983 of subspecies IIIa. Interestingly, the G+C contents of the fimZ, fimY, andfimW genes are less than 46%, which is considerably lower than those of the other six genes of the fim cluster. This study demonstrates that horizontal transmission of all or part of the same gene cluster can occur repeatedly, with the result that different regions of a single gene cluster may have different evolutionary histories.
27
Rosen, David A., Jerome S. Pinkner, Jennifer M. Jones, Jennifer N. Walker, Steven Clegg y Scott J. Hultgren. "Utilization of an Intracellular Bacterial Community Pathway in Klebsiella pneumoniae Urinary Tract Infection and the Effects of FimK on Type 1 Pilus Expression". Infection and Immunity 76, n.º 7 (14 de abril de 2008): 3337–45. http://dx.doi.org/10.1128/iai.00090-08.
Texto completoResumen
ABSTRACT Klebsiella pneumoniae is an important cause of urinary tract infection (UTI), but little is known about its pathogenesis in vivo. The pathogenesis of the K. pneumoniae cystitis isolate TOP52 was compared to that of the uropathogenic Escherichia coli (UPEC) isolate UTI89 in a murine cystitis model. Bladder and kidney titers of TOP52 were lower than those of UTI89 at early time points but similar at later time points. TOP52, like UTI89, formed biofilm-like intracellular bacterial communities (IBCs) within the murine bladder, albeit at significantly lower levels than UTI89. Additionally, filamentation of TOP52 was observed, a process critical for UTI89 evasion of neutrophil phagocytosis and persistence in the bladder. Thus, the IBC pathway is not specific to UPEC alone. We investigated if differences in type 1 pilus expression may explain TOP52's early defect in vivo. The type 1 pilus operon is controlled by recombinase-mediated (fimE, fimB, and fimX) phase variation of an invertible promoter element. We found that K. pneumoniae carries an extra gene of unknown function at the 3′ end of its type 1 operon, fimK, and the genome lacks the recombinase fimX. A deletion mutant of fimK was constructed, and TOP52 ΔfimK had higher titers and formed more IBCs in the murine cystitis model than wild type. The loss of fimK or expression of E. coli fimX from a plasmid in TOP52 resulted in a larger phase-ON population and higher expression levels of type 1 pili and gave TOP52 the ability to form type 1-dependent biofilms. Complementation with pfimK decreased type 1 pilus expression and biofilm formation of TOP52 ΔfimK and decreased UTI89 biofilm formation. Thus, K. pneumoniae appears programmed for minimal expression of type 1 pili, which may explain, in part, why K. pneumoniae is a less prevalent etiologic agent of UTI than UPEC.
28
Kwiecień, Ewelina, Ilona Stefańska, Magdalena Kizerwetter-Świda, Dorota Chrobak-Chmiel, Anna Didkowska, Wojciech Bielecki, Wanda Olech, Krzysztof Anusz y Magdalena Rzewuska. "Prevalence and Genetic Diversity of Trueperella pyogenes Isolated from Infections in European Bison (Bison bonasus)". Animals 12, n.º 14 (18 de julio de 2022): 1825. http://dx.doi.org/10.3390/ani12141825.
Texto completoResumen
Trueperella pyogenes is a Gram-positive bacterium causing purulent infections in many animal species, including the European bison. However, the data about the virulence and genetic relationships of T. pyogenes strains isolated from these wild ruminants are strongly limited. The aim of this study was to investigate the prevalence of T. pyogenes infections in the European bison, and to evaluate the genetic diversity of isolates from these animals. In the time span of 10 years, 328 European bison from 16 different locations were examined. The standard bacteriological methods were used for T. pyogenes isolation and identification from clinical specimens obtained from urogenital tract infections and abscesses of different locations. The presence of genes encoding known virulence factors was investigated by PCR, and the genetic diversity of T. pyogenes strains was examined with the RAPD-PCR method. The prevalence of T. pyogenes infections was 14.6%, and the pathogen was isolated from both female (47.9% of isolates) and male (52.1% of isolates) European bison. It should be highlighted that a considerable number of strains were isolated from the prepuce and penis infections. Therefore, the role of T. pyogenes in the pathogenesis of balanoposthitis should be seriously perceived. A total of 39 T. pyogenes strains were subjected to genetic characterization. All studied strains carried the plo gene, while the nanH (25.6%), nanP (23.1%), cbpA (7.7%), fimA (97.4%), fimC (69.2%), fimE (92.3%) and fimG (15.4%) genes were present with a variable frequency among the tested strains. The virulence genotype plo/fimA/fimC/fimE was dominant. RAPD-PCR typing showed a high level of genetic diversity among European bison T. pyogenes strains, and a total of 31 different RAPD profiles were distinguished. In a few cases, the same RAPD profile was found in strains obtained from animals living in the same area. This study provided the first data about the prevalence and genetic relationships of T. pyogenes in the Polish population of European bison. However, further epidemiological investigations are needed to understand the routes of transmission and dissemination of the pathogen in these wild animals.
29
Johnston, Joanne L., Stephen J. Billington, Volker Haring y Julian I. Rood. "Complementation Analysis of the Dichelobacter nodosus fimN, fimO, and fimP Genes inPseudomonas aeruginosa and Transcriptional Analysis of thefimNOP Gene Region". Infection and Immunity 66, n.º 1 (1 de enero de 1998): 297–304. http://dx.doi.org/10.1128/iai.66.1.297-304.1998.
Texto completoResumen
ABSTRACT The causative agent of ovine footrot, the gram-negative anaerobeDichelobacter nodosus, produces polar type IV fimbriae, which are the major protective antigens. The D. nodosusgenes fimN, fimO, and fimP are homologs of the Pseudomonas aeruginosa fimbrial assembly genes, pilB, pilC, and pilD, respectively. Both the pilD and fimP genes encode prepilin peptidases that are responsible for cleavage of the leader sequence from the immature fimbrial subunit. To investigate the functional similarity of the fimbrial biogenesis systems from these organisms, the D. nodosus genes were introduced intoP. aeruginosa strains carrying mutations in the homologous genes. Analysis of the resultant derivatives showed that thefimP gene complemented a pilD mutant ofP. aeruginosa for both fimbrial assembly and protein secretion. However, the fimN and fimO genes did not complement pilB or pilC mutants, respectively. These results suggest that although the PilD prepilin peptidase can be functionally replaced by the heterologous FimP protein, the function of the PilB and PilC proteins may require binding or catalytic domains specific for the P. aeruginosafimbrial assembly system. The transcriptional organization and regulation of the fimNOP gene region were also examined. The results of reverse transcriptase PCR and primer extension analysis suggested that these genes form an operon transcribed from two ς70-type promoters located upstream of ORFM, an open reading frame proximal to fimN. Transcription of theD. nodosus fimbrial subunit was found to increase in cells grown on solid media, and it was postulated that this regulatory effect may be of significance in the infected footrot lesion.
30
Pearce, A. M., L. I. Irons, A. Robinson y R. N. Seabrook. "Effects of guanidinium hydrochloride on the structure and immunological properties of Bordetella pertussis fimbriae". Biochemical Journal 283, n.º 3 (1 de mayo de 1992): 823–28. http://dx.doi.org/10.1042/bj2830823.
Texto completoResumen
Denaturation of Bordetella pertussis fimbrial preparations by guanidinium hydrochloride (GdnHCl) has been characterized using static light scattering, c.d., fluorescence and antibody recognition. The susceptibility of Fim2 + 3 (a mixed preparation of two fimbrial types) to GdnHCl was found to be highly dependent on pH; as the pH was increased from pH 7.2 to 10.5, the concentration of GdnHCl required to induce 50% denaturation was decreased. At pH 10.5, Fim2 + 3 was denatured by GdnHCl in a three-step pathway comprising: (1) formation of a pre-denaturational intermediate at less than 1.0 M-GdnHCl; (2) dissociation of the fimbrial polymer into subunits between 2 M- and 3.2 M-GdnHCl; and (3) subunit unfolding between 2.8 M- and 3.6 M-GdnHCl. A similar pathway was also found for the denaturation of the individual fimbrial types, Fim2 and Fim3, except that unfolding of either subunit commenced at a lower GdnHCl concentration (2.2 M) than that found for the mixture of fimbriae, Fim2 + 3. The second step in the denaturation pathway, dissociation into subunits, was partially reversible, but the renaturation and reassociation of fully unfolded subunits to form fimbriae-like structures was not achieved. These findings demonstrate that the GdnHCl denaturation of complex polymeric proteins is unlikely to follow a reversible two-state denaturation pathway, and support the involvement of a chaperone-like protein in the folding and assembly of the fimbriae in vivo. Measurement of the ability of anti-fimbrial monoclonal antibodies to recognize intermediates in the denaturation pathway enabled the identification of two types of epitope which were dependent on different aspects of fimbrial tertiary/quaternary structure.
31
Rogovskyy, Artem S., Sara Lawhon, Kathryn Kuczmanski, David C. Gillis, Jing Wu, Helen Hurley, Yuliya V. Rogovska, Kranti Konganti, Ching-Yuan Yang y Kay Duncan. "Phenotypic and genotypic characteristics of Trueperella pyogenes isolated from ruminants". Journal of Veterinary Diagnostic Investigation 30, n.º 3 (12 de marzo de 2018): 348–53. http://dx.doi.org/10.1177/1040638718762479.
Texto completoResumen
Trueperella pyogenes is an opportunistic pathogen that causes suppurative infections in animals including humans. Data on phenotypic and genotypic properties of T. pyogenes isolated from ruminants, particularly goats and sheep, are lacking. We characterized, by phenotypic and genotypic means, T. pyogenes of caprine and ovine origin, and established their phylogenetic relationship with isolates from other ruminants. T. pyogenes isolates ( n = 50) from diagnostic specimens of bovine ( n = 25), caprine ( n = 19), and ovine ( n = 6) origin were analyzed. Overall, variable biochemical activities were observed among the T. pyogenes isolates. The fimbriae-encoding gene, fimE, and neuraminidase-encoding gene, nanH, were, respectively, more frequently detected in the large ( p = 0.0006) and small ( p = 0.0001) ruminant isolates. Moreover, genotype V ( plo/ nanH/ nanP/ fimA/ fimC) was only detected in the caprine and ovine isolates, whereas genotype IX ( plo/ nanP/ fimA/ fimC/ fimE) was solely present in the isolates of bovine origin ( p = 0.0223). The 16S rRNA gene sequences of all T. pyogenes isolates were clustered with the reference T. pyogenes strain ATCC 19411 and displayed a high degree of identity to each other. Our results highlight phenotypic and genotypic diversity among ruminant isolates of T. pyogenes and reinforce the importance of characterization of more clinical isolates to better understand the pathogenesis of this bacterium in different animal species.
32
Benamrouche, Nabila, Hassiba Tali Maamar, Malika Lazri, Sonia Hasnaoui, Abdelkarim Radoui, Ourida Lafer, Rachida Boukari, Chawki Kaddache, Zakia Arrada y Kheira Rahal. "Pertussis in north-central and northwestern regions of Algeria". Journal of Infection in Developing Countries 10, n.º 11 (24 de noviembre de 2016): 1191–99. http://dx.doi.org/10.3855/jidc.7262.
Texto completoResumen
Introduction: Pertussis outbreaks continue to occur in many countries despite high vaccination coverage. Under-diagnosed cases in adolescents and adults may result in increased transmission to infants, who are at risk of severe pertussis. Additional measures to protect both groups should be considered. Methodology: Nasopharyngeal samples and sera were collected from patients and household contacts with clinically suspected pertussis. Diagnoses were confirmed by culture, real-time polymerase chain reaction (PCR), and serology. Bordetella pertussis isolates were characterized by antimicrobial sensitivity and fimbrial serotyping. Results: Of 392 participants, 134/248 patients (54%) and 66/144 contacts (45.8%) had confirmed pertussis infections. B. parapertussis was not detected. All B. pertussis isolates were sensitive to the antibiotics tested, and all expressed the Fim3, not the Fim2, fimbrial serotype. Most patients (81.2%) were <6 months (51.8% of whom were <3 months) of age; 77.6% were unvaccinated, and most positive contacts were mothers 20–40 years of age. Conclusions: Despite high vaccination coverage, pertussis is circulating in Algeria. Most infections occur in unvaccinated infants <6 months of age, with mothers as the main source of infection. An adolescent/adult booster should be considered. Adoption of sensitive and specific laboratory tests would improve pertussis diagnosis and surveillance.
33
Williamson, Peter y Ruth Matthews. "Epitope mapping the Fim2 and Fim3 proteins ofBordetella pertussiswith sera from patients infected with or vaccinated against whooping cough". FEMS Immunology & Medical Microbiology 13, n.º 2 (febrero de 1996): 169–78. http://dx.doi.org/10.1111/j.1574-695x.1996.tb00231.x.
Texto completo
34
WILLIAMSON, P. y R. MATTHEWS. "Epitope mapping the Fim2 and Fim3 proteins of with sera from patients infected with or vaccinated against whooping cough". FEMS Immunology and Medical Microbiology 13, n.º 2 (febrero de 1996): 169–78. http://dx.doi.org/10.1016/0928-8244(95)00123-9.
Texto completo
35
Nguyen Van Cong, S. Fichelson, M. S. Gross, B. Sola, D. Bordereaux, M. F. de Tand, S. Guilhot, S. Gisselbrecht, J. Frézal y P. Tambourin. "The human homologues of Fim1, Fim2/c-Fms, and Fim3, three retroviral integration regions involved in mouse myeloblastic leukemias, are respectively located on chromosomes 6p23, 5q33, and 3q27". Human Genetics 81, n.º 3 (febrero de 1989): 257–63. http://dx.doi.org/10.1007/bf00279000.
Texto completo
36
Oprea, Doinita, Madalina Gabriela Iliescu, Elena Valentina Ionescu, Liliana Elena Stanciu, Lucian Petcu, Sorin Chiriac, Andra Maria Stefan et al. "The Importance of Rehabilitation Programs Using Balneary Treatments in Patients with Spinal Cord Injury". Applied Sciences 12, n.º 18 (18 de septiembre de 2022): 9341. http://dx.doi.org/10.3390/app12189341.
Texto completoResumen
The rehabilitation tools that are designed to improve the function of patients with spinal cord injury (SCI) have various effects. The goals of rehabilitation are to prevent secondary complications, maximize physical functioning, and integrate them into the community. The objective of this study is to evaluate the functional and neurological outcomes of patients with SCI after in-patient rehabilitation in a balneary unit. Methods: one hundred forty-two patients, admitted for primary rehabilitation in a two-year period (2020–2021), aged ≥18 years with SCI, divided into traumatic SCI (T-SCI) and nontraumatic SCI (NT-SCI). The following demographic information was collected: gender, age, studies, occupation, and environment. All patients underwent an initial clinical examination which included diagnosis, causes of SCI, medication, Carmeli score, fall risk, Visual Analogue Scale (VAS) for pain, Functional Independence Measure Motor (FIMm), Functional Independence Measure Cognitive (FIMc), and Functional Independence Measure Total (FIMt). At discharge, the fall risk, VAS, FIMm, FIMc, and FIMt were analyzed. We compared the results between the two groups. Results: T-SCI group was 65 (45.77%) and the NT-SCI group was 77 (54.23%). The study analyzed the effects of rehabilitation on the functional presentation of patients with SCI. It also compared the effects of rehabilitation on T-SCI versus NT-SCI on different outcomes such as age, gender, and clinical–functional impairment. Conclusions: Physical medicine and rehabilitation increase the autonomy of patients. Neurological improvement begins in the first 10 days of complex rehabilitation treatment and is not significantly different between the two groups. The cause of the injury in SCI does not affect the results of the rehabilitation.
37
Kelly, Arlene, Colin Conway, Tadhg Ó Cróinín, Stephen G. J. Smith y Charles J. Dorman. "DNA Supercoiling and the Lrp Protein Determine the Directionality of fim Switch DNA Inversion in Escherichia coli K-12". Journal of Bacteriology 188, n.º 15 (1 de agosto de 2006): 5356–63. http://dx.doi.org/10.1128/jb.00344-06.
Texto completoResumen
ABSTRACT Site-specific recombinases of the integrase family usually require cofactors to impart directionality in the recombination reactions that they catalyze. The FimB integrase inverts the Escherichia coli fim switch (fimS) in the on-to-off and off-to-on directions with approximately equal efficiency. Inhibiting DNA gyrase with novobiocin caused inversion to become biased in the off-to-on direction. This directionality was not due to differential DNA topological distortion of fimS in the on and off phases by the activity of its resident P fimA promoter. Instead, the leucine-responsive regulatory (Lrp) protein was found to determine switching outcomes. Knocking out the lrp gene or abolishing Lrp binding sites 1 and 2 within fimS completely reversed the response of the switch to DNA relaxation. Inactivation of either Lrp site alone resulted in mild on-to-off bias, showing that they act together to influence the response of the switch to changes in DNA supercoiling. Thus, Lrp is not merely an architectural element organizing the fim invertasome, it collaborates with DNA supercoiling to determine the directionality of the DNA inversion event.
38
Lo, Alvin, Christine Seers, Stuart Dashper, Catherine Butler, Glenn Walker, Katrina Walsh, Deanne Catmull et al. "FimR and FimS: Biofilm Formation and Gene Expression in Porphyromonas gingivalis". Journal of Bacteriology 192, n.º 5 (8 de enero de 2010): 1332–43. http://dx.doi.org/10.1128/jb.01211-09.
Texto completoResumen
ABSTRACT Porphyromonas gingivalis is a late-colonizing bacterium of the subgingival dental plaque biofilm associated with periodontitis. Two P. gingivalis genes, fimR and fimS, are predicted to encode a two-component signal transduction system comprising a response regulator (FimR) and a sensor histidine kinase (FimS). In this study, we show that fimS and fimR, although contiguous on the genome, are not part of an operon. We inactivated fimR and fimS in both the afimbriated strain W50 and the fimbriated strain ATCC 33277 and demonstrated that both mutants formed significantly less biofilm than their respective wild-type strains. Quantitative reverse transcription-real-time PCR showed that expression of fimbriation genes was reduced in both the fimS and fimR mutants of strain ATCC 33277. The mutations had no effect, in either strain, on the P. gingivalis growth rate or on the response to hydrogen peroxide or growth at pH 9, at 41°C, or at low hemin availability. Transcriptome analysis using DNA microarrays revealed that inactivation of fimS resulted in the differential expression of 10% of the P. gingivalis genome (>1.5-fold; P < 0.05). Notably genes encoding seven different transcriptional regulators, including the fimR gene and three extracytoplasmic sigma factor genes, were differentially expressed in the fimS mutant.
39
Feil, Helene, William S. Feil, John C. Detter, Alexander H. Purcel y Steven E. Lindow. "Site-Directed Disruption of the fimA and fimF Fimbrial Genes of Xylella fastidiosa". Phytopathology® 93, n.º 6 (junio de 2003): 675–82. http://dx.doi.org/10.1094/phyto.2003.93.6.675.
Texto completoResumen
Xylella fastidiosa causes Pierce's disease, a serious disease of grape, citrus variegated chlorosis, almond and oleander leaf scorches, and many other similar diseases. Although the complete genome sequences of several strains of this organism are now available, the function of most genes in this organism, especially those conferring virulence, is lacking. Attachment of X. fastidiosa to xylem vessels and insect vectors may be required for virulence and transmission; therefore, we disrupted fimA and fimF, genes encoding the major fimbrial protein FimA and a homolog of the fimbrial adhesin MrkD, to determine their role in the attachment process. Disruption of the fimA and fimF genes in Temecula1 and STL grape strains of X. fastidiosa was obtained by homologous recombination using plasmids pFAK and pFFK, respectively. These vectors contained a kanamycin resistance gene cloned into either the fimA or fimF genes of X. fastidiosa grape strains Temecula1 or STL. Efficiency of transformation was sufficiently high (≈600 transformants per μg of pFFK DNA) to enable selection of rare recombination events. Polymerase chain reaction and Southern blot analyses of the mutants indicated that a double crossover event had occurred exclusively within the fimA and fimF genes, replacing the chromosomal gene with the disrupted gene and abolishing production of the corresponding proteins, FimA or FimF. Scanning electron microscopy revealed that fimbriae size and number, cell aggregation, and cell size were reduced for the FimA¯ or FimF¯ mutants of X. fastidiosa when compared with the parental strain. FimA¯ or FimF¯ mutants of X. fastidiosa remained pathogenic to grapevines, with bacterial populations slightly reduced compared with those of the wild-type X. fastidiosa cells. These mutants maintained their resistance to kanamycin in planta for at least 6 months in the greenhouse.
40
Nguyen, Anh H. V., Hoan T. Pham y Cao Huu Nghia. "Molecular Epidemiology of Bordetella pertussis Strains Isolated in Vietnam During 2015–2017". Infection Control & Hospital Epidemiology 41, S1 (octubre de 2020): s319—s320. http://dx.doi.org/10.1017/ice.2020.916.
Texto completoResumen
Background: Whooping cough is a serious respiratory illness in infants caused by Bordetella pertussis. In spite of the vaccination program, the incidence rates of whooping cough per 100,000 population in Vietnam increased from 0.33 in 2015 to 0.58 in 2017. If this represents a pertussis resurgence, contributors may include pathogen adaptation, the spread of specific variants, vaccine failure, and failure to effectively treat cases and contacts. There has been little research in Vietnam on B. pertussis strains. Therefore, we investigated the molecular epidemiology of circulating B. pertussis strains in Southern Vietnam by applying multilocus sequence typing (MLST) for 7 housekeeping genes and 4 antigenic determinant genes as components in the acellular vaccine including prn, ptxP, ptxS1, and fim3. Methods: DNA was extracted from 15 isolates collected from 263 case patients during 2015–2017 and was subject to MLST using primers and cycling conditions from the Bordetella pubMLST website (www.Pubmlst.org/Bordetella/). The products were analyzed using BioEdit version 7.2.5 software and then were aligned and compared to reference sequences of each genotype in the database. The evolutionary relationship among sequence types (STs) from housekeeping genes was performed as a minimum spanning tree via the goeBURST algorithm, whereas the correlation of different variants from 4 antigenic determinant genes was built up and clarified with phylogenetic trees based on the UPGMA method by MEGA 7 program. Results: The 15 isolates were all classified as ST2 (100%) by MLST of housekeeping genes, and they belonged to a common global clonal group (Fig. 1). Sequencing of antigenic determinant genes prn2 – ptxP3 – ptxS1-1 – fim3-1 determined that all were identical to each another and the reference sequences (Fig. 2). Conclusions:B. pertussis isolates circulating in Southern Vietnam appeared to be the same as the common global strain. Few isolates were available for testing; therefore, continued surveillance is important to confirm these findings and to monitor population changes over time.Funding: NoneDisclosures: None
41
Debrie, Anne-Sophie, Loïc Coutte, Dominique Raze, Frits Mooi, Frances Alexander, Andrew Gorringe, Nathalie Mielcarek y Camille Locht. "Construction and evaluation of Bordetella pertussis live attenuated vaccine strain BPZE1 producing Fim3". Vaccine 36, n.º 11 (marzo de 2018): 1345–52. http://dx.doi.org/10.1016/j.vaccine.2018.02.017.
Texto completo
42
Tsang, R. S. W., A. K. H. Lau, M. L. Sill, S. A. Halperin, P. Van Caeseele, F. Jamieson y I. E. Martin. "Polymorphisms of the Fimbria fim3 Gene of Bordetella pertussis Strains Isolated in Canada". Journal of Clinical Microbiology 42, n.º 11 (1 de noviembre de 2004): 5364–67. http://dx.doi.org/10.1128/jcm.42.11.5364-5367.2004.
Texto completo
43
Stentebjerg-Olesen, Bodil, Trinad Chakraborty y Per Klemm. "Type 1 Fimbriation and Phase Switching in a NaturalEscherichia coli fimB Null Strain, Nissle 1917". Journal of Bacteriology 181, n.º 24 (15 de diciembre de 1999): 7470–78. http://dx.doi.org/10.1128/jb.181.24.7470-7478.1999.
Texto completoResumen
ABSTRACT Escherichia coli Nissle 1917 has been used as a probiotic against intestinal disorders for many decades. It is a good colonizer of the human gut and has been reported to be able to express type 1 fimbriae. Type 1 fimbriae are surface organelles which mediate α-d-mannose-sensitive binding to various host cell surfaces. The expression is phase variable, and two tyrosine recombinases, FimB and FimE, mediate the inversion of the fimbrial phase switch. Current evidence suggests that FimB can carry out recombination in both directions, whereas FimE-catalyzed switching is on to off only. We show here that under liquid shaking growth conditions, Nissle 1917 did not express type 1 fimbriae, due to a truncation of the fimB gene by an 1,885-bp insertion element. Despite its fimB null status, Nissle 1917 was still capable of off-to-on switching of the phase switch and expressing type 1 fimbriae when grown under static conditions. This phase switching was not catalyzed by FimE, by truncated FimB, or by information residing within the insertion element. No further copies offimB seemed to be present on the chromosome of Nissle 1917, suggesting that another tyrosine recombinase in Nissle 1917 is responsible for the low-frequency off-to-on inversion of the phase switch that is strongly favored under static growth conditions. This is the first report documenting the non-FimB- or non-FimE-catalyzed inversion of the fim switch.
44
Guo, Yuru. "Antimicrobial Resistance and Virulence Genes Distribution in Trueperella pyogenes Isolated from Dairy Cows with Clinical Mastitis in Liaoning of China". Pakistan Veterinary Journal 41, n.º 03 (1 de agosto de 2021): 329–34. http://dx.doi.org/10.29261/pakvetj/2021.040.
Texto completoResumen
Trueperella pyogenes is considered as a causative agent of many infections, such as mastitis, endometritis, pneumonia, liver abscessation. T. pyogenes can express several virulence genes such as plo, fimA, cbpA, nanH and nanP contributing to its pathogenicity. The aim of this study was to provide an investigation about antimicrobial resistance, as well as virulence genes distribution and gene cassettes among T. pyogenes isolates from dairy cows with clinical mastitis. The susceptibility to different antimicrobial agents was determined by the Broth Microdilution Method, and virulence genes and gene cassette was detected by polymerase chain reactions (PCRs). There are 10.49% (17/162) of milk samples from dairy cows with mastitis were positive for T. pyogenes. High levels of resistance were found to clindamycin (23.53%), oxytetracycline (23.53%), ciprofloxacin (47.06%), sulfamethoxazole/trimethoprim (100%). Moreover, all isolates carried class I integrons, and gene cassette arrays were aadA9 (2/17) or aadA5-dfrA17 (3/17). Finally, all isolates harbored plo nanH and fimA genes, but other genes encoding virulence genes including fimC, fimE, nanP and cbpA are ranged from 47.06% to 88.23%. Our study showed T. pyogenes isolates from dairy cows with clinical mastitis were susceptible to β-lactams. In addition, all seven virulence genes occurred in isolates, and plo, nanH, and fimA gene showed a significantly higher frequency in T. pyogenes of the Liaoning Province, China.
45
Oguchi, Kaoru, Akiko Miyata, Yukimasa Kazuyama, Atsuya Noda, Eri Suzuki, Mineo Watanabe y Tetsuo Nakayama. "Detection of antibodies against fimbria type 3 (Fim3) is useful diagnostic assay for pertussis". Journal of Infection and Chemotherapy 21, n.º 9 (septiembre de 2015): 639–46. http://dx.doi.org/10.1016/j.jiac.2015.05.006.
Texto completo
46
Feil, Helene, William S. Feil y Steven E. Lindow. "Contribution of Fimbrial and Afimbrial Adhesins of Xylella fastidiosa to Attachment to Surfaces and Virulence to Grape". Phytopathology® 97, n.º 3 (marzo de 2007): 318–24. http://dx.doi.org/10.1094/phyto-97-3-0318.
Texto completoResumen
The role of fimbrial and afimbrial adhesins of Xylella fastidiosa in biofilm formation was assessed by visualization of cell aggregates of mutant strains after incubation on glass surfaces. FimA- or FimF- fimbrial mutants adhered as solitary cells at a slightly lesser frequency to glass surfaces than the parental strain; however, cell aggregates were not formed, unlike the wild-type strain. Conversely, whereas the XadA- and HxfB- nonfimbrial mutants also exhibited a much lower frequency of adherence to glass surfaces than the wild-type strain, most of the cells retained on the surfaces were in cell aggregates of different sizes, much like that of the parental strain. Neither fimbrial or afimbrial mutants formed a mature biofilm on the sides of flasks of broth cultures, unlike the dense biofilm formed by the wild-type strain. Although FimA- and FimF- mutants did not form cell aggregates on glass surfaces when incubated as individual strains, aggregates of a FimA- or FimF- mutant were observed when co-incubated with either a XadA- mutant or HxfB- mutant, respectively. These results are consistent with a model in which the fimbrial adhesins FimA and FimF are involved preferentially in cell-to-cell aggregate formation whereas the afimbrial adhesions XadA and HxfB preferentially contribute to initial cell binding to surfaces, whereupon further cell aggregation can occur. In each of five separate experiments, FimA, FimF, XadA, and HxfB mutants of X. fastidiosa all were less virulent to grape than the corresponding wild-type strain. Fimbrial and afimbrial mutants might produce a reduced biofilm within vessels of grape and, hence, be deficient in various cell-density-dependent traits required for movement through the plant and, thus, virulence.
47
Burns, Lesley S., Stephen G. J. Smith y Charles J. Dorman. "Interaction of the FimB Integrase with thefimS Invertible DNA Element in Escherichia coliIn Vivo and In Vitro". Journal of Bacteriology 182, n.º 10 (15 de mayo de 2000): 2953–59. http://dx.doi.org/10.1128/jb.182.10.2953-2959.2000.
Texto completoResumen
ABSTRACT The FimB protein is a site-specific recombinase that inverts thefimS genetic switch in Escherichia coli. Based on amino acid sequence analysis alone, FimB has been assigned to the integrase family of tyrosine recombinases. We show that amino acid substitutions at positions R47, H141, R144, and Y176, corresponding to highly conserved members of the catalytic motif of integrase proteins, render FimB incapable of inverting the fimS element in vivo. The arginine substitutions reduced the ability of FimB to bind tofimS in vivo or in vitro, while the substitution R144Q resulted in a protein unable to bind independently to the half sites located at the left end of fimS in phase-on bacteria. These data confirm that FimB is an integrase and suggest that residue R144 has a role in binding to a specific component of the fimswitch.
48
Zaitsev, E. M., I. G. Bazhanova y M. V. Britsina. "Protective Activity and Safety of Acellular Pertussis Vaccine from Vaccine and Freshly Isolated Strain Bordetella pertussis". Epidemiology and Vaccine Prevention 16, n.º 2 (20 de abril de 2017): 31–34. http://dx.doi.org/10.31631/2073-3046-2017-16-2-31-34.
Texto completoResumen
Goal. Study of the protective activity and safety of acellular pertussis vaccine (APV) using freshly isolated strain of B. pertussis. Materials and methods. Mice-hybrids F1 (CBAxC57Bl6). The B. pertussis strains: vaccine strains No. 305, No. 203, freshly isolated strain No. 287, the test neurotropic strain culture of B. pertussis No. 18323. Protective properties of the APV evaluated in accordance with the guidelines. Toxicity APV was studied by changes of body weight of mice, histamine-sensitizing properties, according to the instructions. The results and discussion. The paper presents the study of the safety and protective activity of three options acellular pertussis vaccine (APV) containing a complex of protective antigens of pertussis microbe: APV1 of vaccine strains of B. pertussis No. 305, serovariant 1.2.0, the gene for the pertussis toxin ptxA2, pertactin prnl gene, genes fimbria 2 and 3 - fim2-1 and fim3A and strain No. 203, serovariant 1.2.3, the gene for the pertussis toxin ptxA4, pertactin prnl gene, genes fimbria - fim2-1 and fim3A; APV2 of freshly isolated strain of B. pertussis No. 287, serovariant 1.0.3, the gene for the pertussis toxin ptxAl, gene pertactin prn2 genes fimbria -fim2-1 and fim3В; APV3 of strains No. 305, No. 203 and No. 287. Shows the relationship between the protective activity of the APV and genetic types, pertussis toxin, pertactin and fimrie in their composition. Protective activity APV1, APV2 and APV3 when infecting dose of 345 LD50 was 9.0 IPU/ml (international protective units per ml) of 10.3 IPU/ml and 19.9 IPU/ml, respectively. At extremely high dose of infection (3846 LD50) protective properties possessed only APV3, protective activity it was 9.2IPU/ml, in line with who requirements - at least 8 IPU/ml. Conclusion. Enhancing the protective effects of the vaccine APV3 and freshly isolated strain can be explained by the stimulation of cellular and humoral immunity to a broader spectrum of antigenic alternative structures in pertussis toxin, pertactin and fimrie.
49
Blumer, Caroline, Alexandra Kleefeld, Daniela Lehnen, Margit Heintz, Ulrich Dobrindt, Gábor Nagy, Kai Michaelis et al. "Regulation of type 1 fimbriae synthesis and biofilm formation by the transcriptional regulator LrhA of Escherichia coli". Microbiology 151, n.º 10 (1 de octubre de 2005): 3287–98. http://dx.doi.org/10.1099/mic.0.28098-0.
Texto completoResumen
Type 1 fimbriae of Escherichia coli facilitate attachment to the host mucosa and promote biofilm formation on abiotic surfaces. The transcriptional regulator LrhA, which is known as a repressor of flagellar, motility and chemotaxis genes, regulates biofilm formation and expression of type 1 fimbriae. Whole-genome expression profiling revealed that inactivation of lrhA results in an increased expression of structural components of type 1 fimbriae. In vitro, LrhA bound to the promoter regions of the two fim recombinases (FimB and FimE) that catalyse the inversion of the fimA promoter, and to the invertible element itself. Translational lacZ fusions with these genes and quantification of fimE transcript levels by real-time PCR showed that LrhA influences type 1 fimbrial phase variation, primarily via activation of FimE, which is required for the ON-to-OFF transition of the fim switch. Enhanced type 1 fimbrial expression as a result of lrhA disruption was confirmed by mannose-sensitive agglutination of yeast cells. Biofilm formation was stimulated by lrhA inactivation and completely suppressed upon LrhA overproduction. The effects of LrhA on biofilm formation were exerted via the changed levels of surface molecules, most probably both flagella and type 1 fimbriae. Together, the data show a role for LrhA as a repressor of type 1 fimbrial expression, and thus as a regulator of the initial stages of biofilm development and, presumably, bacterial adherence to epithelial host cells also.
50
Zhou, Ge, Wen-Jun Mo, Peter Sebbel, Guangwei Min, Thomas A. Neubert, Rudi Glockshuber, Xue-Ru Wu, Tung-Tien Sun y Xiang-Peng Kong. "Uroplakin Ia is the urothelial receptor for uropathogenicEscherichia coli: evidence from in vitro FimH binding". Journal of Cell Science 114, n.º 22 (15 de noviembre de 2001): 4095–103. http://dx.doi.org/10.1242/jcs.114.22.4095.
Texto completoResumen
The binding of uropathogenic Escherichia coli to the urothelial surface is a crucial initial event for establishing urinary tract infection because it allows the bacteria to gain a foothold on the urothelial surface, thus preventing them from being removed by micturition. In addition, it triggers bacterial invasion as well as host urothelial defense. This binding is mediated by the FimH adhesin located at the tip of the bacterial type 1-fimbrium, a filamentous attachment apparatus, and its urothelial receptor. We have prepared a biotinylated, recombinant FimH-FimC adhesin:chaperone complex and used it to identify its mouse urothelial receptor. The FimH-FimC complex binds specifically to a single 24 kDa major mouse urothelial plaque protein, which we identified as uroplakin Ia by mass spectrometry, cDNA cloning and immunoreactivity. The terminal mannosyl moieties on Asn-169 of uroplakin Ia are responsible for FimH as well as concanavalin A binding. Although FimH binds to uroplakin Ia with only moderate strength (Kd ∼100 nM between pH 4 and 9), the binding between multiple fimbriae of a bacterium and the crystalline array of polymerized uroplakin receptors should achieve high avidity and stable bacterial attachment. The FimH-FimC complex binds preferentially to the mouse urothelial umbrella cells in a pattern similar to uroplakin staining. Our results indicate that the structurally related uroplakins Ia and Ib are glycosylated differently, that uroplakin Ia serves as the urothelial receptor for the type 1-fimbriated E. coli, and that the binding of uropathogenic bacteria to uroplakin Ia may play a key role in mediating the urothelial responses to bacterial attachment.