| 1. |
- Brandhagen, Martin, 1984, et al.
(författare)
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Alcohol and macronutrient intake patterns are related to general and central adiposity.
- 2012
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Ingår i: European journal of clinical nutrition. - : Springer Science and Business Media LLC. - 1476-5640 .- 0954-3007. ; 66, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- Background/Objectives:Alcohol and dietary fat have high energy densities and may therefore be related to body weight and fat deposition. We studied associations between alcohol and macronutrient intake patterns and general and central adiposity.Subjects/Methods:A population-based cross-sectional study of 524 men and 611 women. The participants answered a dietary questionnaire describing habitual food consumption including intake of alcoholic beverages. Macronutrient intake was analysed in relation to anthropometric measures and dual energy X-ray absorptiometry determined body fat.Results:In women, total alcohol intake was negatively associated with body fat percentage (β:-0.67, P<0.01). In men, total alcohol intake was positively associated with sagittal abdominal diameter (SAD) (β: 0.28, P=0.01). In addition, positive associations were found between intake of alcohol from spirits and body fat percentage (β: 1.17, P<0.05), SAD (β: 0.52, P<0.05) and waist circumference (β: 2.29, P=0.01). In men, protein intake was positively associated with body mass index (BMI) (β: 0.03, P=0.001), body fat percentage (β: 0.04, P<0.05), SAD (β: 0.02, P=0.01) and waist circumference (β: 0.09, P<0.01). Also in men only, negative associations between fat intake and BMI (β: -0.03, P<0.01), SAD (β: -0.02, P<0.05) and waist circumference (β: -0.05, P<0.05) were found.Conclusions:Alcohol intake was inversely associated to relative body fat in women whereas spirits consumption was positively related to central and general obesity in men. Macronutrient intakes, particularly protein and fat, were differently associated with obesity indicators in men versus women. This may reflect a differential effect by gender, or differential obesity related reporting errors in men and women.European Journal of Clinical Nutrition advance online publication, 16 November 2011; doi:10.1038/ejcn.2011.189.
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| 2. |
- Egge-Jacobsen, Wolfgang, et al.
(författare)
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O-Linked glycosylation of the PilA pilin protein of francisella tularensis : identification of the endogenous protein-targeting oligosaccharyltransferase and characterization of the native oligosaccharide
- 2011
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Ingår i: Journal of Bacteriology. - Baltimore : Williams & Wilkins. - 0021-9193 .- 1098-5530. ; 193:19, s. 5487-5497
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Tidskriftsartikel (refereegranskat)abstract
- Findings from a number of studies suggest that the PilA pilin proteins may play an important role in the pathogenesis of disease caused by species within the genus Francisella. As such, a thorough understanding of PilA structure and chemistry is warranted. Here, we definitively identified the PglA protein-targeting oligosaccharyltransferase by virtue of its necessity for PilA glycosylation in Francisella tularensis and its sufficiency for PilA glycosylation in Escherichia coli. In addition, we used mass spectrometry to examine PilA affinity purified from Francisella tularensis subsp. tularensis and F. tularensis subsp. holarctica and demonstrated that the protein undergoes multisite, O-linked glycosylation with a pentasaccharide of the structure HexNac-HexHex-HexNac-HexNac. Further analyses revealed microheterogeneity related to forms of the pentasaccharide carrying unusual moieties linked to the distal sugar via a phosphate bridge. Type A and type B strains of Francisella subspecies thus express an O-linked protein glycosylation system utilizing core biosynthetic and assembly pathways conserved in other members of the proteobacteria. As PglA appears to be highly conserved in Francisella species, O-linked protein glycosylation may be a feature common to members of this genus.
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| 3. |
- Balonova, Lucie, et al.
(författare)
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Characterization of protein glycosylation in Francisella tularensis subsp holarctica
- 2012
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- FTH_0069 is a previously uncharacterized strongly immunoreactive protein that has been proposed to be a novel virulence factor in Francisella tularensis. Here, the glycan structure modifying two C-terminal peptides of FTH_0069 was identified utilizing high resolution, high mass accuracy mass spectrometry, combined with in-source CID tandem MS experiments. The glycan observed at m/z 1156 was determined to be a hexasaccharide, consisting of two hexoses, three N-acetylhexosamines, and an unknown monosaccharide containing a phosphate group. The monosaccharide sequence of the glycan is tentatively proposed as X-P-HexNAc-HexNAc-Hex-Hex-HexNAc, where X denotes the unknown monosaccharide. The glycan is identical to that of DsbA glycoprotein, as well as to one of the multiple glycan structures modifying the type IV pilin PilA, suggesting a common biosynthetic pathway for the protein modification. Here, we demonstrate that the glycosylation of FTH_0069, DsbA, and PilA was affected in an isogenic mutant with a disrupted wbtDEF gene cluster encoding O-antigen synthesis and in a mutant with a deleted pglA gene encoding pilin oligosaccharyltransferase PglA. Based on our findings, we propose that PglA is involved in both pilin and general F. tularensis protein glycosylation, and we further suggest an inter-relationship between the O-antigen and the glycan synthesis in the early steps in their biosynthetic pathways. Molecular & Cellular Proteomics 11: 10.1074/mcp.M111.015016, 1-12, 2012.
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| 4. |
- Bröms, Jeanette, et al.
(författare)
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Dissection of homologous translocon operons reveals a distinct role for YopD in type III secretion by Yersinia pseudotuberculosis
- 2003
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Ingår i: Microbiology. - : Microbiology Society Journals. - 1350-0872 .- 1465-2080. ; 149:9, s. 2615-2626
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Tidskriftsartikel (refereegranskat)abstract
- The homologous pcrGVHpopBD and lcrGVHyopBD translocase operons of Pseudomonas aeruginosa and pathogenic Yersinia spp., respectively, are responsible for the translocation of anti-host effectors into the cytosol of infected eukaryotic cells. In Yersinia, this operon is also required for yop-regulatory control. To probe for key molecular interactions during the infection process, the functional interchangeability of popB/yopB and popD/yopD was investigated. Secretion of PopB produced in trans in a yopB null mutant of Yersinia was only observed when co-produced with its native chaperone PcrH, but this was sufficient to complement the yopB translocation defect. The Yersinia yopD null mutant synthesized and secreted PopD even in the absence of native PcrH, yet this did not restore YopD-dependent yop-regulatory control or effector translocation. Thus, this suggests that key residues in YopD, which are not conserved in PopD, are essential for functional Yersinia type III secretion.
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| 5. |
- Bröms, Jeanette, et al.
(författare)
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PcrH of Pseudomonas aeruginosa is essential for secretion and assembly of the type III translocon
- 2003
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 0022-1899 .- 1537-6613. ; 188:12, s. 1909-1921
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Tidskriftsartikel (refereegranskat)abstract
- Pseudomonas aeruginosa harbors a type III secretion system that translocates antihost effectors into an infected eukaryotic cell. PcrH is a key component of type III secretion in this essential virulence strategy. In the absence of PcrH, P. aeruginosa is translocation deficient because of a specific reduction in presecretory stability and subsequent secretion of PopB and PopD, 2 proteins essential for the translocation process. PcrH exerts this chaperone function by binding directly to PopB and PopD. Consistent with the genetic relatedness of PcrH with LcrH of pathogenic Yersinia species, these proteins are functionally interchangeable with respect to their ability to complement the translocation defect associated with either a lcrH or pcrH null mutant, respectively. Thus, the translocator class of chaperones performs a critical function in ensuring the assembly of a translocation competent type III secreton. Finally, unlike the regulatory roles of other translocator-class chaperones (e.g., LcrH, SicA of Salmonella enterica, and IpgC of Shigella species), in vitro regulation of P. aeruginosa type III secretion does not involve PcrH.
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| 6. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
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Direct repeat-mediated deletion of a type IV pilin gene results in major virulence attenuation of Francisella tularensis
- 2006
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Ingår i: Molecular Microbiology. - : Wiley-Blackwell. - 0950-382X .- 1365-2958. ; 59:6, s. 1818-1830
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis, the causative agent of tularaemia, is a highly infectious and virulent intracellular pathogen. There are two main human pathogenic subspecies, Francisella tularensis ssp. tularensis (type A), and Francisella tularensis ssp. holarctica (type B). So far, knowledge regarding key virulence determinants is limited but it is clear that intracellular survival and multiplication is one major virulence strategy of Francisella. In addition, genome sequencing has revealed the presence of genes encoding type IV pili (Tfp). One genomic region encoding three proteins with signatures typical for type IV pilins contained two 120 bp direct repeats. Here we establish that repeat-mediated loss of one of the putative pilin genes in a type B strain results in severe virulence attenuation in mice infected by subcutaneous route. Complementation of the mutant by introduction of the pilin gene in cis resulted in complete restoration of virulence. The level of attenuation was similar to that of the live vaccine strain and this strain was also found to lack the pilin gene as result of a similar deletion event mediated by the direct repeats. Presence of the pilin had no major effect on the ability to interact, survive and multiply inside macrophage-like cell lines. Importantly, the pilin-negative strain was impaired in its ability to spread from the initial site of infection to the spleen. Our findings indicate that this putative pilin is critical for Francisella infections that occur via peripheral routes.
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| 7. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
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Hfq, a novel pleiotropic regulator of virulence-associated genes in Francisella tularensis
- 2009
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Ingår i: Infection and Immunity. - : American society for microbiology. - 0019-9567 .- 1098-5522. ; 77:5, s. 1866-80
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is a highly infectious pathogen that infects animals and humans, causing tularemia. The ability to replicate within macrophages is central for virulence and relies on expression of genes located in the Francisella pathogenicity island (FPI), as well as expression of other genes. Regulation of FPI-encoded virulence gene expression in F. tularensis involves at least four regulatory proteins and is not fully understood. Here we studied the RNA-binding protein Hfq in F. tularensis and particularly the role that it plays as a global regulator of gene expression in stress tolerance and pathogenesis. We demonstrate that Hfq promotes resistance to several cellular stresses (including osmotic and membrane stresses). Furthermore, we show that Hfq is important for the ability of the F. tularensis vaccine strain LVS to induce disease and persist in organs of infected mice. We also demonstrate that Hfq is important for stress tolerance and full virulence in a virulent clinical isolate of F. tularensis, FSC200. Finally, microarray analyses revealed that Hfq regulates expression of numerous genes, including genes located in the FPI. Strikingly, Hfq negatively regulates only one of two divergently expressed putative operons in the FPI, in contrast to the other known regulators, which regulate the entire FPI. Hfq thus appears to be a new pleiotropic regulator of virulence in F. tularensis, acting mostly as a repressor, in contrast to the other regulators identified so far. Moreover, the results obtained suggest a novel regulatory mechanism for a subset of FPI genes.
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| 8. |
- Forslund, Anna-Lena, 1964-
(författare)
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Identification of new virulence factors in Francisella tularensis
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Francisella tularensis, the causative agent of tularemia, is a highly virulent bacterium with an infection dose of less than ten bacteria. The ability of a pathogen to cause infection relies on different virulence mechanisms, but in Francisella tularensis relatively few virulence factors are known. Two F. tularensis subspecies are virulent in humans; the highly virulent subspecies tularensis, also referred to as type A, and the less virulent subspecies holarctica, also called type B. The aim of this thesis has been to improve the knowledge regarding the ability of Francisella to cause disease, with the emphasis on surface located and membrane associated proteins and structures. In addition I have also investigated how virulence is regulated by studying the role of the small RNA chaperone, Hfq.The genome of Francisella appears to encode few regulatory genes. In my work I found that Hfq has an important role in regulation of virulence associated genes in Francisella. Similar to what has been found in other pathogens, Hfq functions in negative regulation, and this is the first time a negative regulation has been described for genes in the Francisella pathogenicity island. Another protein with a key role in virulence is a homologue to a disulphide oxidoreductase, DsbA, which was identified as an outer membrane lipoprotein in Francisella. A dsbA mutant was found to be severely attenuated for virulence and also induced protection against wild-type infections, thus making it a candidate for exploration as a new live vaccine. Additional genes with homology to known virulence determinants include a type IV pilin system. The pilin homologue, PilA, was identified to be required for full virulence in both type A and type B strains. In addition, genes involved in pili assembly and secretion, pilC and pilQ, were also found to be virulence associated in the type A strain.In summary, dsbA, hfq and type IV pili associated genes were indentified to be virulence determinants in F. tularensis. DsbA is a potential target for drug development and a dsbA mutant a candidate for a new live vaccine strain. Furthermore the identification of Hfq as a novel regulatory factor opens new insights into the virulence regulatory network in Francisella.
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| 9. |
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| 10. |
- Forslund, Anna-Lena, 1964-, et al.
(författare)
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The type IV pilin, PilA, is required for full virulence of Francisella tularensis subspecies tularensis
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Annan publikation (populärvet., debatt m.m.)abstract
- Background: All four Francisella tularensis subspecies possess gene clusters with potential to express type IV pili (Tfp). These clusters include putative pilin genes, as well as pilB, pilC and pilQ, required for secretion and assembly of Tfp. A hallmark of Tfp is the ability to retract the pilus upon surface contact, a property mediated by the ATPase PilT. Interestingly, out of the two major human pathogenic subspecies only the highly virulent type A strains have a functional pilT gene.Results: In a previous study, we were able to show that one pilin gene, pilA, was essential for virulence of a type B strain in a mouse infection model. In this work we have examined the role of several pilin genes in the virulence of the pathogenic type A strain SCHU S4. pilA, pilC, pilQ, and pilT were mutated by in-frame deletion mutagenesis. Interestingly, when mice were infected with a mixture of each mutant strain and the wild-type strain, the pilA, pilC and pilQ mutants were out-competed, while the pilT mutant was equally competitive as the wild-type.Conclusions: This suggests that expression and surface localisation of PilA contribute to virulence in the highly virulent type A strain, while PilT was dispensable for virulence in the mouse infection model.
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