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- Johansson, Maria U, et al.
(författare)
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Structure, specificity, and mode of interaction for bacterial albumin-binding modules.
- 2002
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Ingår i: Journal of Biological Chemistry. - 1083-351X .- 0021-9258. ; 277:10, s. 8114-8120
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Tidskriftsartikel (refereegranskat)abstract
- We have determined the solution structure of an albumin binding domain of protein G, a surface protein of group C and G streptococci. We find that it folds into a left handed three-helix bundle similar to the albumin binding domain of protein PAB from Peptostreptococcus magnus. The two domains share 59% sequence identity, are thermally very stable, and bind to the same site on human serum albumin. The albumin binding site, the first determined for this structural motif known as the GA module, comprises residues spanning the first loop to the beginning of the third helix and includes the most conserved region of GA modules. The two GA modules have different affinities for albumin from different species, and their albumin binding patterns correspond directly to the host specificity of C/G streptococci and P. magnus, respectively. These studies of the evolution, structure, and binding properties of the GA module emphasize the power of bacterial adaptation and underline ecological and medical problems connected with the use of antibiotics.
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| 2. |
- Aspholm-Hurtig, Marina, et al.
(författare)
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Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
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Tidskriftsartikel (refereegranskat)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
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| 6. |
- Hagger, Martin S., et al.
(författare)
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Physical self-perceptions in adolescence : Generalizability of a hierarchical multidimensional model across three cultures
- 2003
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Ingår i: Journal of Cross-Cultural Psychology. - Beverly Hills, CA : Sage Publications. - 0022-0221 .- 1552-5422. ; 34:6, s. 611-628
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the generalizability of the form, structural parameters, and latent means of a hierarchical multidimensional model of physical self-perceptions in adolescents from three cultures. A children's version of the physical self-perception profile (PSPP-C) was administered to samples of British, Hong Kong, and Russian high school students. A structural equation model that hypothesized a hierarchical structure with global self-esteem as a superordinate construct and physical self-worth as a domain-level construct governing the PSPP-C subdomains fit the data adequately. Tests of the cross-cultural generalizability of the proposed model supported the invariance of the factor pattern and model parameters across the samples. Latent means analysis suggested that the factor means were significantly higher in the British sample, a finding that supports the results of cross-cultural studies of self-esteem in other domains.
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| 8. |
- Ryder, Edward, et al.
(författare)
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The DrosDel collection : a set of P-element insertions for generating custom chromosomal aberrations in Drosophila melanogaster.
- 2004
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Ingår i: Genetics. - 0016-6731. ; 167:2, s. 797-813
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Tidskriftsartikel (refereegranskat)abstract
- We describe a collection of P-element insertions that have considerable utility for generating custom chromosomal aberrations in Drosophila melanogaster. We have mobilized a pair of engineered P elements, p[RS3] and p[RS5], to collect 3243 lines unambiguously mapped to the Drosophila genome sequence. The collection contains, on average, an element every 35 kb. We demonstrate the utility of the collection for generating custom chromosomal deletions that have their end points mapped, with base-pair resolution, to the genome sequence. The collection was generated in an isogenic strain, thus affording a uniform background for screens where sensitivity to genetic background is high. The entire collection, along with a computational and genetic toolbox for designing and generating custom deletions, is publicly available. Using the collection it is theoretically possible to generate >12,000 deletions between 1 bp and 1 Mb in size by simple eye color selection. In addition, a further 37,000 deletions, selectable by molecular screening, may be generated. We are now using the collection to generate a second-generation deficiency kit that is precisely mapped to the genome sequence.
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| 9. |
- Sjölund, Maria, et al.
(författare)
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Long-term persistence of resistant Enterococcus species after antibiotics to eradicate Helicobacter pylori
- 2003
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Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819 .- 1539-3704. ; 139:6, s. 483-7
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Antibiotic treatment selects for resistance not only in the pathogen to which it is directed but also in the indigenous microflora. OBJECTIVE: To determine whether a widely used regimen (clarithromycin, metronidazole, and omeprazole) for Helicobacter pylori eradication affects resistance development in enterococci. DESIGN: Cohort study. SETTING: Endoscopy units at 3 community hospitals in Sweden. PATIENTS: 5 consecutive dyspeptic patients who were colonized with H. pylori, had endoscopy-confirmed duodenal ulcer, and received antibiotic treatment, and 5 consecutive controls with dyspepsia but no ulcer who did not receive treatment. MEASUREMENTS: Fecal samples were obtained from patients and controls before, immediately after, 1 year after, and 3 years after treatment. From each patient and sample, enterococci were isolated and analyzed for DNA fingerprint, clarithromycin susceptibility, and presence of the erm(B) gene. RESULTS: In treated patients, all enterococci isolated immediately after treatment showed high-level clarithromycin resistance due to erm(B). In 3 patients, resistant enterococci persisted for 1 to 3 years after treatment. No resistance developed among controls. CONCLUSION: A common H. pylori treatment selects for highly resistant enterococci that can persist for at least 3 years without further selection.
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