Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bordetella pertussis 18323 produces a bvg-regulated 39.1-kDa porin-like protein, OmpQ. OmpQ had 61% similarity to the major porin of B. pertussis and contains conserved regions common to both the neisserial and enteric porin families. The results of Southern blot analysis indicate that strains of Bordetella parapertussis and Bordetella bronchiseptica but not Bordetella avium contain this gene.
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PMID:Identification of a Bordetella pertussis bvg-regulated porin-like protein. 783 16

A shared-primer PCR method for the detection of infection was developed by using primers derived from DNA sequences upstream of the structural genes for the porin proteins of Bordetella pertussis and Bordetella parapertussis. This method resulted in a 159-bp PCR product specific for B. pertussis and a 121-bp DNA fragment specific for B. parapertussis and allowed for the simultaneous detection of these pathogens. The PCR procedure was shown to be very specific since no PCR product was obtained from 36 non-Bordetella bacterial DNAs. Nasopharyngeal aspirates (NPAs) from children suspected of having pertussis were evaluated by the PCR method, culture, and the Chinese hamster ovary (CHO) cell assay, which detects pertussis toxin. B. pertussis was cultured from 119 of 205 NPAs assayed, and the presence of pertussis toxin was detected in 69 of the NPAs by the CHO cell assay. When ethidium bromide staining was used to detect PCR products, 100 NPAs gave positive results by shared-primer PCR; 94 of these NPAs were also positive by culture. The result indicated a sensitivity of 79% for PCR when culture was used as the standard. The sensitivity of PCR was increased to 95% when a digoxigenin immunoblot system was used. An additional 20 NPAs from patients with suspected pertussis that were culture negative also gave positive results by PCR. The specific and sensitive PCR method described here should be useful for both the clinical diagnosis of pertussis and case identification in vaccine trials.
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PMID:Identification of Bordetella pertussis infection by shared-primer PCR. 819 94

Using atomic force microscopy (AFM), we obtained high-resolution surface images of the bacterial outer membrane channels Escherichia coli OmpF porin and Bordetella pertussis porin that were reconstituted in artificial bilayer membranes as two-dimensional crystalline arrays. These porins were chosen because they are among the most extensively studied proteins of this type and are known for their well-defined crystalline nature in the native membrane. Such reconstituted membrane proteins are ideal specimens to assess the suitability and resolution of AFM for imaging biomembranes and associated proteins. Although OmpF porin often showed a mixed pattern of rectangular and hexagonal arrays with approximately 8.4 x 9.8- and approximately 7.2-nm-spacings, respectively, B. pertussis porin showed mostly a rectangular pattern with an approximately 7.9 x 13.8-nm spacing. The packing patterns of the E. coli OmpF porin in the membrane are very close to those found in electron-microscopic studies. When B. pertussis porin was imaged in a buffer solution, its trimeric subunits were apparently resolved, and the surface of each monomer revealed beadlike structures. This is the first report of such a high-resolution structural analysis of B. pertussis porin by any imaging method. We also imaged the lipid bilayer itself as an internal control for imaging and to further ascertain the resolution. Individual polar head groups of bilayer lipid molecules were resolved, suggesting the intrinsic resolution of AFM for bioimaging.
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PMID:Imaging of reconstituted biological channels at molecular resolution by atomic force microscopy. 821 41

We have examined the surface topography and channel connectivity of a naturally crystalline porin that is known to be functional, and whose structure has not been perturbed by detergent extraction. A three-dimensional density map, calculated from two independent tilt series of negatively stained cell envelopes, reveals three separate channels per trimer on one side (the 'smooth' side), and a single common opening at the other ('rough') side. This arrangement is consistent with the molecular structures recently determined at high resolution by X-ray crystallography for three other porins after detergent solubilization, and implies that the Bordetella pertussis porin may have the same kind of folding. Surface relief maps calculated from electron micrographs of cell envelopes contrasted by unidirectional shadowing clearly show that the side with single opening (i.e. the rough side) represents the external surface.
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PMID:Orientation of porin channels in the outer membrane of Bordetella pertussis. 841 96

The gene coding for the anion-specific porin of the halophilic eubacterium Ectothiorhodospira (Ect.) vacuolata was cloned and sequenced, the first such gene so analyzed from a purple sulfur bacterium. It encodes a precursor protein consisting of 374 amino acid (aa)-residues including a signal peptide of 22-aa residues. Comparison with aa sequences of porins from several other members of the Proteobacteria revealed little homology. Only two regions showed local homology with the previously sequenced porins of Neisseria species, Comamonas acidovorans, Bordetella pertussis, Alcaligenes eutrophus, and Burkholderia cepacia. Genomic Southern blot hybridization studies were carried out with a probe derived from the 5' end of the gene coding for the porin of Ect. vacuolata. Two related species, Ect. haloalkaliphila and Ect. shaposhnikovii, exhibited a clear signal, while the extremely halophilic bacterium Halorhodospira (Hlr.) halophila (formerly Ect. halophila) did not show any cross-hybridization even at low stringency. This result is in good accordance with a recently proposed reassignment within the family Ectothiorhodospiraceae, which included the separation of the extremely halophilic species into the new genus Halorhodospira.
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PMID:Porin from the halophilic species Ectothiorhodospira vacuolata: cloning, structure of the gene and comparison with other porins. 921 24

Immunization with whole-cell pertussis vaccines (WCV) containing heat-killed Bordetella pertussis cells and with acellular vaccines containing genetically or chemically detoxified pertussis toxin (PT) in combination with filamentous hemagglutinin (FHA), pertactin (Prn), or fimbriae confers protection in humans and animals against B. pertussis infection. In an earlier study we demonstrated that FHA is involved in the adherence of these bacteria to human bronchial epithelial cells. In the present study we investigated whether mouse antibodies directed against B. pertussis FHA, PTg, Prn, and fimbriae, or against two other surface molecules, lipopolysaccharide (LPS) and the 40-kDa outer membrane porin protein (OMP), that are not involved in bacterial adherence, were able to block adherence of B. pertussis and B. parapertussis to human bronchial epithelial cells. All antibodies studied inhibited the adherence of B. pertussis to these epithelial cells and were equally effective in this respect. Only antibodies against LPS and 40-kDa OMP affected the adherence of B. parapertussis to epithelial cells. We conclude that antibodies which recognize surface structures on B. pertussis or on B. parapertussis can inhibit adherence of the bacteria to bronchial epithelial cells, irrespective whether these structures play a role in adherence of the bacteria to these cells.
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PMID:Role of antibodies against Bordetella pertussis virulence factors in adherence of Bordetella pertussis and Bordetella parapertussis to human bronchial epithelial cells. 1002 42

No standardized PCR method is available for the laboratory diagnosis of the pertussis syndrome. Consensus recommendations for the use of PCR in the diagnosis of Bordetella pertussis infections have been proposed, and the aim of this study was to develop a method that fulfills all of these criteria. A rapid-cycle shared-primer PCR method with a microwell format and probe hybridization detection step (POR) was developed using novel oligonucleotides targeted to the outer membrane porin gene (Bordetella spp.). In specimens positive for Bordetella spp., B. pertussis was differentiated from Bordetella parapertussis and Bordetella bronchiseptica by hybridization with organism-specific oligonucleotide probes. An internal control was developed using overlap extension PCR and mouse beta-actin DNA. The analytical specificity was 100%. The analytical sensitivity was comparable to that of nested IS481 and IS1001 PCR ( approximately 1 organism per reaction). The clinical sensitivity and specificity were ascertained using 705 specimens (from 705 patients). The results were compared to those of a nested-PCR method targeting the insertion sequences IS481 and IS1001. Fifty-one specimens were positive for B. pertussis by POR and IS481 PCR. Two specimens which fulfilled a clinical definition of pertussis were positive by POR and negative by IS481 PCR. A total of 652 specimens were negative by both methods. B. parapertussis was not detected in any specimens. PCR inhibition was detected in 21 out of 705 specimens (2.98%). Thus, a rapid (4 h, including specimen preparation) PCR method which fulfills all of the consensus recommendations was developed and validated for the detection of B. pertussis.
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PMID:Rapid-cycle PCR method to detect Bordetella pertussis that fulfills all consensus recommendations for use of PCR in diagnosis of pertussis. 1110 86

Many virulence factors secreted from pathogenic Gram-negative bacteria are autotransporter proteins. The final step of autotransporter secretion is C --> N-terminal threading of the passenger domain through the outer membrane (OM), mediated by a cotranslated C-terminal porin domain. The native structure is formed only after this final secretion step, which requires neither ATP nor a proton gradient. Sequence analysis reveals that, despite size, sequence, and functional diversity among autotransporter passenger domains, >97% are predicted to form parallel beta-helices, indicating this structural topology may be important for secretion. We report the folding behavior of pertactin, an autotransporter passenger domain from Bordetella pertussis. The pertactin beta-helix folds reversibly in isolation, but folding is much slower than expected based on size and native-state topology. Surprisingly, pertactin is not prone to aggregation during folding, even though folding is extremely slow. Interestingly, equilibrium denaturation results in the formation of a partially folded structure, a stable core comprising the C-terminal half of the protein. Examination of the pertactin crystal structure does not reveal any obvious reason for the enhanced stability of the C terminus. In vivo, slow folding would prevent premature folding of the passenger domain in the periplasm, before OM secretion. Moreover, the extra stability of the C-terminal rungs of the beta-helix might serve as a template for the formation of native protein during OM secretion; hence, vectorial folding of the beta-helix could contribute to the energy-independent translocation mechanism. Coupled with the sequence analysis, the results presented here suggest a general mechanism for autotransporter secretion.
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PMID:Pertactin beta-helix folding mechanism suggests common themes for the secretion and folding of autotransporter proteins. 1654 96

PCR has greatly facilitated pertussis diagnosis due to the speed, sensitivity, and specificity of this assay compared to other detection methods. Various single-target PCR assays are currently utilized, but none is universally considered to be the "gold standard." Our aim was to assess the use of multitarget versus single-target PCR for the diagnosis of pertussis in clinical samples. PCR assays targeting insertion sequence IS481 (IS), pertussis toxin ptxA promoter region (PT), and outer membrane porin (PO), or recA (RA) were evaluated in respiratory specimens collected from 4,442 patients with suspected pertussis. The diagnosis of pertussis was confirmed in 309 (6.96%) patients by the 3-target IS-PT-PO/RA PCR versus 247 (5.56%) by the conventional single-target IS (P=0.007). Compared to single-target IS, the three-target combination increased the proportion of positive specimens by 1.25-fold, and two-target combinations increased the proportion of positive specimens by 1.10- to 1.24-fold. In addition, nine cases of B. parapertussis infection were also confirmed by using the discriminative features of this multitarget PCR. Of the 89 culture-proven pertussis cases, 17 (19.1%) and 5 of the 16 patients (31.3%) admitted to intensive care unit would have been missed had only the single-target IS PCR been applied. Patients with mild disease (P=0.004) and shorter hospitalization (P=0.006) were less likely to have positive cultures. This consensus generating real-time PCR approach permits a sensitive detection, as well as an accurate species identification of the causative Bordetella pathogens for the timely management of patients.
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PMID:Multitarget PCR for diagnosis of pertussis and its clinical implications. 1715 Dec 10

Pertussis (whooping cough), caused by Bordetella pertussis is a severe, acute contagious disease of the respiratory system and it affects mostly children and also susceptible individuals of all ages. Although the conventional culture method used for diagnosis is highly specific, it has a lower sensitivity. Therefore, there is a need for a sensitive, specific and rapid method for diagnosis of pertussis. Polymerase chain reaction (PCR), introduced recently as a new approach for diagnosis of pertussis, has been shown to be more sensitive than culture method. Pertussis toxin gene (ptxA-Pr), insertion sequence genes (IS481 and IS1001), adenylate cyclase genes and structural porin and flagellin genes were chosen as targets for PCR, in different studies. This study aimed to develop and optimize a diagnostic inhouse PCR method by using primers specific for ptxA-Pr and IS481 gene regions. An in-house PCR method was developed by using primer pairs of PTp1/PTp2 specific for ptxA-Pr gene and PIp1/PIp2 specific for IS481 gene and DNAs of various bacterial reference strains. Throat samples obtained from 45 healthy individuals and B.pertussis reference strain with decreasing concentrations were mixed to constitute a group of "representative clinical samples" and used to test and optimize sensitivity and specificity of the method. The in-house PCR with PTp1/PTp2 primers showed a very high specificity but a low sensitivity with a value of 34.4 cfu/Rm (colony forming unit/reaction mixture). Whereas, the inhouse PCR with PIp1/PIp2 primers exhibited a low specificity due to cross-reactivity with B. Pertussis and B.bronchiseptica but much higher sensitivity with a value of 1.12 cfu/Rm. The experiments performed with the representative clinical samples yielded similar results. Simultaneously applied cultivation studies indicated the detection limit of the PCR method as 2 x 103 cfu/ml. Based on our results, the PCR targeting IS481 gene had high sensitivity while the PCR targeting ptxA-Pr gene had high specificity. It was concluded that, PCR method targeting the IS481 gene might be used for pre-diagnosis and then PCR for ptxA-Pr gene might be applied for the confirmation of B.pertussis in the molecular diagnosis of pertussis.
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PMID:[Development and optimization of an in-house PCR method for molecular diagnosis of pertussis]. 2209 Feb 94


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