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| 2. |
- Bröms, Jeanette E, et al.
(författare)
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Mapping of a YscY binding domain within the LcrH chaperone that is required for regulation of Yersinia type III secretion
- 2005
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Ingår i: Journal of Bacteriology. - : American Society for Microbiology. - 0021-9193 .- 1098-5530. ; 187:22, s. 7738-7752
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Tidskriftsartikel (refereegranskat)abstract
- Type III secretion systems are used by many animal and plant interacting bacteria to colonize their host. These systems are often composed of at least 40 genes, making their temporal and spatial regulation very complex. Some type III chaperones of the translocator class are important regulatory molecules, such as the LcrH chaperone of Yersinia pseudotuberculosis. In contrast, the highly homologous PcrH chaperone has no regulatory effect in native Pseudomonas aeruginosa or when produced in Yersinia. In this study, we used LcrH-PcrH chaperone hybrids to identify a discrete region in the N terminus of LcrH that is necessary for YscY binding and regulatory control of the Yersinia type III secretion machinery. PcrH was unable to bind YscY and the homologue Pcr4 of P. aeruginosa. YscY and Pcr4 were both essential for type III secretion and reciprocally bound to both substrates YscX of Yersinia and Pcr3 of P. aeruginosa. Still, Pcr4 was unable to complement a DeltayscY null mutant defective for type III secretion and yop-regulatory control in Yersinia, despite the ability of YscY to function in P. aeruginosa. Taken together, we conclude that the cross-talk between the LcrH and YscY components represents a strategic regulatory pathway specific to Yersinia type III secretion.
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| 3. |
- Carlsson, Gunnar E, 1930, et al.
(författare)
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Attitudes toward dental appearance in 50- and 60-year-old subjects living in Sweden
- 2008
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Ingår i: Journal of Esthetic and Restorative Dentistry. - : Wiley. - 1496-4155 .- 1708-8240. ; 20:1, s. 46-56
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Tidskriftsartikel (refereegranskat)abstract
- Background: Attitudes towards the importance of general appearance has varied much not only over time but also among groups of individuals of different age and other characteristics. Whether the situation is similar regarding dental appearance does not seem to have been studied. Purpose: The aim was to study differences in attitudes towards dental appearance between two large samples of 50- and 60-year-old subjects. Materials and Methods: Identical questionnaires were sent to all subjects born in 1942 and 1952 living in two Swedish counties in 2002 (n=17444; n50=8881; n60=8563). The final response rate was 72.2% (n=12599). In this study, responses to four statements on the importance of dental appearance have been analyzed with respect to gender and age. Results: Many of the responses to the four statements differed with gender and age. To the first statement (“To have beautiful and perfect teeth is very important for how you are treated by other people”), 73 % agreed at age 60 compared to 64 % at age 50 (P < 0.001). Approximately 90 % of the subjects agreed to the second statement (“Minor aesthetic imperfections of the teeth have no importance, only they function well”). Logistic regression indicated that several variables were significantly associated with the statements. Besides age and gender, education and self-assessed dental problems were most important. Conclusion: Attitudes towards the importance of dental appearance differed both between genders and age groups. CLINICAL SIGNIFICANCE The varying attitudes towards dental appearance in the population must be acknowledged in treatment decisions.
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| 4. |
- Carlsson, Gunnar E, 1930, et al.
(författare)
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Occlusie en gebitsslitage
- 2015
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Ingår i: Occlusie en articulatie. - 978 90 8562 141 6 ; , s. 62-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Carlsson, Katrin E, et al.
(författare)
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Extracytoplasmic-stress-responsive pathways modulate type III secretion in Yersinia pseudotuberculosis.
- 2007
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Ingår i: Infect Immun. - 0019-9567. ; 75:8, s. 3913-24
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Tidskriftsartikel (refereegranskat)abstract
- Three signal transduction pathways, the two-component systems CpxRA and BaeSR and the alternative sigma factor sigma(E), respond to extracytoplasmic stress that facilitates bacterial adaptation to changing environments. At least the CpxRA and sigma(E) pathways control the production of protein-folding and degradation factors that counter the effects of protein misfolding in the periplasm. This function also influences the biogenesis of multicomponent extracellular appendages that span the bacterial envelope, such as various forms of pili. Herein, we investigated whether any of these regulatory pathways in the enteropathogen Yersinia pseudotuberculosis affect the functionality of the Ysc-Yop type III secretion system. This is a multicomponent molecular syringe spanning the bacterial envelope used to inject effector proteins directly into eukaryotic cells. Disruption of individual components revealed that the Cpx and sigma(E) pathways are important for Y. pseudotuberculosis type III secretion of Yops (Yersinia outer proteins). In particular, a loss of CpxA, a sensor kinase, reduced levels of structural Ysc (Yersinia secretion) components in bacterial membranes, suggesting that these mutant bacteria are less able to assemble a functional secretion apparatus. Moreover, these bacteria were no longer capable of localizing Yops into the eukaryotic cell interior. In addition, a cpxA lcrQ double mutant engineered to overproduce and secrete Yops was still impaired in intoxicating cells. Thus, the Cpx pathway might mediate multiple influences on bacterium-target cell contact that modulate Yersinia type III secretion-dependent host cell cytotoxicity.
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| 6. |
- Carlsson, Katrin E, et al.
(författare)
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Influence of the Cpx extracytoplasmic-stress-responsive pathway on Yersinia sp.-eukaryotic cell contact.
- 2007
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Ingår i: Infect Immun. - 0019-9567. ; 75:9, s. 4386-99
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Tidskriftsartikel (refereegranskat)abstract
- The extracytoplasmic-stress-responsive CpxRA two-component signal transduction pathway allows bacteria to adapt to growth in extreme environments. It controls the production of periplasmic protein folding and degradation factors, which aids in the biogenesis of multicomponent virulence determinants that span the bacterial envelope. This is true of the Yersinia pseudotuberculosis Ysc-Yop type III secretion system. However, despite using a second-site suppressor mutation to restore Yop effector secretion by yersiniae defective in the CpxA sensor kinase, these bacteria poorly translocated Yops into target eukaryotic cells. Investigation of this phenotype herein revealed that the expression of genes which encode several surface-located adhesins is also influenced by the Cpx pathway. In particular, the expression and surface localization of invasin, an adhesin that engages beta1-integrins on the eukaryotic cell surface, are severely restricted by the removal of CpxA. This reduces bacterial association with eukaryotic cells, which could be suppressed by the ectopic production of CpxA, invasin, or RovA, a positive activator of inv expression. In turn, these infected eukaryotic cells then became susceptible to intoxication by translocated Yop effectors. In contrast, bacteria harboring an in-frame deletion of cpxR, which encodes the cognate response regulator, displayed an enhanced ability to interact with cell monolayers, as well as elevated inv and rovA transcription. This phenotype could be drastically suppressed by providing a wild-type copy of cpxR in trans. We propose a mechanism of inv regulation influenced by the direct negative effects of phosphorylated CpxR on inv and rovA transcription. In this fashion, sensing of extracytoplasmic stress by CpxAR contributes to productive Yersinia sp.-eukaryotic cell interactions.
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| 7. |
- Costa, Tiago R. D., et al.
(författare)
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Influence of the LcrH chaperone on type III secretion system regulation in Yersinia pseudotuberculosis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Human pathogenic Yersiniae share a common virulence plasmid that encodes for the Ysc-Yop type III secretion system (T3SS). Control of yop expression involves several pathways in which their cross-talk is not completely understood. LcrF, an AraC-like transcriptional activator, is required for temperature-dependent yop-transcription. In contrast, a repressive effect of the T3S chaperone LcrH and the cognate translocator substrate YopD occurs through binding to yop mRNA and inhibiting translation; a process that is also thought to involve LcrQ. Several homologous members of the LcrH family of translocator-class of T3S chaperones can act as a cofactor to amplify the activity of transcriptional activators analogous to LcrF. However, we show here in Y. pseudotuberculosis that LcrH does not induce LcrF-dependent transcription of target genes. Moreover, a full length DlcrH null mutant in which YopB and YopD are rapidly degraded is totally de-repressed for Yop synthesis even though the anti-activator LcrQ is forced to accumulate in the cytoplasm through rendering the Ysc-Yop T3SS non-functional or ectopically producing LcrQ in trans. Typically, this mutant cannot grow at 37°C. Thus, in all respects, the DlcrH null mutant mirrors the regulatory defects established for Yersinia lacking the translocator and anti-activator YopD. On the other hand, Y. pseudotuberculosis producing the LcrHE30G point mutant that is defective for YscY chaperone binding exhibits a mild regulatory defect that permits some growth at 37°C, but is blind to the cytoplasmic accumulation of LcrQ. Critically however, this mutant still responds to repression caused by YopD accumulation, which is stably produced and efficiently secreted by this strain. Thus, our work with LcrHE30G indicates an additional regulatory function of this versatile T3S chaperone that is independent of the LcrF transcription factor and the YopD anti-activator.
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| 8. |
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| 9. |
- Johansson, Anders, 1957, et al.
(författare)
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A 10-year longitudinal study of self-assessed chewing ability and dental status in 50-year-old subjects.
- 2007
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Ingår i: Int J Prosthodont. ; 20:6, s. 643-645
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Tidskriftsartikel (refereegranskat)abstract
- Chewing ability and dental status were assessed in two Swedish counties by questionnaires sent in 1992 and in 2002 to all subjects born in 1942. Those who answered both questionnaires – at ages 50 and 60 – were included in the study (n = 5008). The proportion of those who reported chewing ability as very good decreased from 75 % to 66 % during the 10-year follow-up. Approximately 80 % of complete denture wearers considered their chewing ability to be good. Chewing ability was reported to be worse at age 60 than at age 50, although there was only a minor impairment in dental status
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| 10. |
- Johansson, Ann-Katrin, et al.
(författare)
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A 15-yr longitudinal study of xerostomia in a Swedish population of 50-yr-old subjects
- 2009
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Ingår i: EUROPEAN JOURNAL OF ORAL SCIENCES. - : Wiley. - 0909-8836 .- 1600-0722. ; 117:1, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the changes in prevalence of xerostomia in subjects from 50 to 65 yr of age. Questionnaires were sent to all subjects who were born in 1942 and were living in two Swedish counties in 1992, 1997, 2002, and 2007. The analyses focused on those who answered the questionnaires both in 1992 and in 2007. The response rate was 71.4% (n = 6,346) in 1992 and 73.1% (n = 6,078) in 2007. Of those who answered the questionnaire in 1992, 74.3% (n = 4,714) also responded in 2007. There was an almost linear increase in the prevalence of xerostomia at the four study time-points (i.e. when the subjects were 50, 55, 60, and 65 yr of age). Xerostomia was more prevalent at night than during the day. The pooled prevalence of night-time and daytime xerostomia was 6% at 50 yr of age and 15% at 65 yr of age, and it was higher in women than in men on both occasions. Logistic regression analyses showed that impaired health and smoking were significantly associated with daytime xerostomia but not with night-time xerostomia. Despite the increase in prevalence of xerostomia from 50 to 65 yr of age, there was considerable variation during the observation period. The incidence rate was 13% (507/4,015) and the disappearance rate was 42% (104/250) (dichotomized answers).
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