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| 2. |
- Forsberg, Göte, et al.
(författare)
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Presence of bacteria and innate immunity of intestinal epithelium in childhood celiac disease
- 2004
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Ingår i: American Journal of Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 0002-9270 .- 1572-0241. ; 99:5, s. 894-904
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Exposure to gliadin and related prolamins and appropriate HLA-DQ haplotype are necessary but not sufficient for contracting celiac disease (CD). Aberrant innate immune reactions could be contributing risk factors. Therefore, jejunal biopsies were screened for bacteria and the innate immune status of the epithelium investigated.METHODS: Children with untreated, treated, challenged CD, and controls were analyzed. Bacteria were identified by scanning electron microscopy. Glycocalyx composition and mucin and antimicrobial peptide production were studied by quantitative RT-PCR, antibody and lectin immunohistochemistry.RESULTS: Rod-shaped bacteria were frequently associated with the mucosa of CD patients, with both active and inactive disease, but not with controls. The lectin Ulex europaeus agglutinin I (UEAI) stained goblet cells in the mucosa of all CD patients but not of controls. The lectin peanut agglutinin (PNA) stained glycocalyx of controls but not of CD patients. mRNA levels of mucin-2 (MUC2), alpha-defensins HD-5 and HD-6, and lysozyme were significantly increased in active CD and returned to normal in treated CD. Their expression levels correlated to the interferon-gamma mRNA levels in intraepithelial lymphocytes. MUC2, HD-5, and lysozyme proteins were seen in absorptive epithelial cells. beta-defensins hBD-1 and hBD-2, carcinoembryonic antigen (CEA), CEA cell adhesion molecule-1a (CEACAM1a), and MUC3 were not affected.CONCLUSIONS: Unique carbohydrate structures of the glycocalyx/mucous layer are likely discriminating features of CD patients. These glycosylation differences could facilitate bacterial adhesion. Ectopic production of MUC2, HD-5, and lysozyme in active CD is compatible with goblet and Paneth cell metaplasia induced by high interferon-gamma production by intraepithelial lymphocytes.
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| 4. |
- Hedberg, Maria E, 1959-, et al.
(författare)
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Lachnoanaerobaculum a new genus in Lachnospiraceae; characterization of Lachnoanaerobaculum umeaense gen. nov., sp. nov., isolated from human small intestine, Lachnoanaerobaculum orale gen. nov., sp. nov., isolated from saliva and reclassification of Eubacterium saburreum (Prevot) Holdeman and Moore 1970 as Lachnoanaerobaculum saburreum comb. nov.
- 2012
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Ingår i: International Journal of Systematic and Evolutionary Microbiology. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 62:11, s. 2685-2690
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Tidskriftsartikel (refereegranskat)abstract
- Two new obligately anaerobic Gram-positive, saccharolytic and non-proteolytic spore-forming bacilli (strain CD3:22 and N1) are described. Strain CD3:22 was isolated from a biopsy of the small intestine of a child with celiac disease and strain N1 from the saliva of a healthy young man. The cells of both strains were observed to be filamentous with lengths of approximately 5 to >20 µm, some of them curving and with swellings. The novel organisms produced H2S, NH3, butyric acid and acetic acid as major metabolic end products. Phylogenetic analyses, based on comparative 16S rRNA gene sequencing, revealed close relationships (98 % sequence similarity) between the two isolates, as well as the type strain of Eubacterium saburreum CCUG 28089T and four other Lachnospiraceae bacterium/E. saburreum-like organisms. This group of bacteria were clearly different from any of the 19 known genera in the family Lachnospiraceae. While Eubacterium spp. are reported to be non-spore-forming, reanalysis of E. saburreum CCUG 28089T confirmed that the bacterium, indeed, is able to form spores. Based on 16S rRNA gene sequencing, phenotypic and biochemical properties, CD3:22 (CCUG 58757T) and N1 (CCUG 60305T) represent new species of a new and distinct genus, named Lachnoanaerobaculum, in the family Lachnospiraceae [within the order Clostridiales, class Clostridia, phylum Firmicutes]. Strain CD3:22 is the type strain of the type species, Lachnoanaerobaculum umeaense gen. nov., sp. nov., of the proposed new genus. Strain N1 is the type strain of the species, Lachnoanaerobaculum orale gen. nov., sp. nov. Moreover, E. saburreum CCUG 28089T is reclassified as Lachnoanaerobaculum saburreum comb. nov.
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| 5. |
- Hedberg, Maria E, et al.
(författare)
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Lachnoanaerobaculum gen. nov., a new genus in the Lachnospiraceae: characterization of Lachnoanaerobaculum umeaense gen. nov., sp. nov., isolated from the human small intestine, and Lachnoanaerobaculum orale sp. nov., isolated from saliva, and reclassification of Eubacterium saburreum (Prevot 1966) Holdeman and Moore 1970 as Lachnoanaerobaculum saburreum comb. nov.
- 2012
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Ingår i: International journal of systematic and evolutionary microbiology. - : Microbiology Society. - 1466-5034 .- 1466-5026. ; 62:Pt 11, s. 2685-90
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Tidskriftsartikel (refereegranskat)abstract
- Two novel obligately anaerobic, Gram-stain-positive, saccharolytic and non-proteolytic spore-forming bacilli (strains CD3 : 22(T) and N1(T)) are described. Strain CD3 : 22(T) was isolated from a biopsy of the small intestine of a child with coeliac disease, and strain N1(T) from the saliva of a healthy young man. The cells of both strains were observed to be filamentous, approximately 5 to >20 µm long, some of them curving and with swellings. The novel organisms produced H(2)S, NH(3), butyric acid and acetic acid as major metabolic end products. Phylogenetic analyses, based on comparative 16S rRNA gene sequencing, revealed close relationships (98 % sequence similarity) between the two isolates, as well as the type strain of Eubacterium saburreum and four other Lachnospiraceae bacterium-/E. saburreum-like organisms. This group of bacteria were clearly different from any of the 19 known genera in the family Lachnospiraceae. While Eubacterium species are reported to be non-spore-forming, reanalysis of E. saburreum CCUG 28089(T) confirmed that the bacterium is indeed able to form spores. Based on 16S rRNA gene sequencing, phenotypic and biochemical properties, strains CD3 : 22(T) and N1(T) represent novel species of a new and distinct genus, named Lachnoanaerobaculum gen. nov., in the family Lachnospiraceae [within the order Clostridiales, class Clostridia, phylum Firmicutes]. Strain CD3 : 22(T) ( = CCUG 58757(T) = DSM 23576(T)) is the type strain of the type species, Lachnoanaerobaculum umeaense gen. nov., sp. nov., of the proposed new genus. Strain N1(T) ( = CCUG 60305(T) = DSM 24553(T)) is the type strain of Lachnoanaerobaculum orale sp. nov. Moreover, Eubacterium saburreum is reclassified as Lachnoanaerobaculum saburreum comb. nov. (type strain CCUG 28089(T) = ATCC 33271(T) = CIP 105341(T) = DSM 3986(T) = JCM 11021(T) = VPI 11763(T)).
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| 7. |
- Hueting, David A., et al.
(författare)
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Design, structure and plasma binding of ancestral β-CoV scaffold antigens
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- We report the application of ancestral sequence reconstruction on coronavirus spike protein, resulting in stable and highly soluble ancestral scaffold antigens (AnSAs). The AnSAs interact with plasma of patients recovered from COVID-19 but do not bind to the human angiotensin-converting enzyme 2 (ACE2) receptor. Cryo-EM analysis of the AnSAs yield high resolution structures (2.6–2.8 Å) indicating a closed pre-fusion conformation in which all three receptor-binding domains (RBDs) are facing downwards. The structures reveal an intricate hydrogen-bonding network mediated by well-resolved loops, both within and across monomers, tethering the N-terminal domain and RBD together. We show that AnSA-5 can induce and boost a broad-spectrum immune response against the wild-type RBD as well as circulating variants of concern in an immune organoid model derived from tonsils. Finally, we highlight how AnSAs are potent scaffolds by replacing the ancestral RBD with the wild-type sequence, which restores ACE2 binding and increases the interaction with convalescent plasma.
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| 8. |
- Ihse, Elisabet, 1977-
(författare)
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Two Types of Fibrils in ATTR Amyloidosis : Implications for Clinical Phenotype and Treatment Outcome
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic amyloidoses are a group of lethal diseases where proteins aggregate into fibrillar structures, called amyloid fibrils, that deposits throughout the body. Transthyretin (TTR) causes one type of amyloidosis, in which the aggregates mainly infiltrate nervous and cardiac tissue. Almost a hundred different mutations in the TTR gene are known to trigger the disease, but wild-type (wt) TTR is also incorporated into the fibrils, and may alone form amyloid. Patients with the TTRV30M mutation show, for unknown reasons, two clinical phenotypes. Some have an early onset of disease without cardiomyopathy while others have a late onset and cardiomyopathy. It has previously been described that amyloid fibrils formed from TTRV30M can have two different compositions; either with truncated molecules beside full-length TTR (type A) or only-full-length molecules (type B). In this thesis, the clinical importance of the two types of amyloid fibrils was investigated. We found that the fibril composition types are correlated to the two clinical phenotypes seen among TTRV30M patients, with type A fibrils present in late onset patients and type B fibrils in early onset patients. The only treatment for hereditary TTR amyloidosis has been liver transplantation, whereby the liver producing the mutant TTR is replaced by an organ only producing wt protein. However, in some patients, cardiac symptoms progress post-transplantationally. We demonstrated that the propensity to incorporate wtTTR differs between fibril types and tissue types in TTRV30M patients, with cardiac amyloid of type A having the highest tendency. This offers an explanation to why particularly cardiac amyloidosis develops after transplantation, and suggests which patients that are at risk for such development. By examining patients with other mutations than TTRV30M, we showed that, in contrast to the general belief, a fibril composition with truncated TTR is very common and might even be the general rule. This may explain why TTRV30M patients often have a better outcome after liver transplantation than patients with other mutations. In conclusion, this thesis has contributed with one piece to the puzzle of understanding the differences in clinical phenotype and treatment response between TTR amyloidosis patients, by demonstrating corresponding differences at a molecular level.
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| 9. |
- Laursen, Louise, 1988-
(författare)
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Exploring the Role of the PDZ Domain in a Supramodule
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The postsynaptic density (PSD) is a large, dense and membraneless compartment of proteins associated below the postsynaptic membrane bilayer, and which constantly undergoes morphological alteration in response to synaptic activity. Formation of PSD is associated with liquid-liquid phase separation of scaffold proteins in complex with other PSD proteins. PSD-95, one of the most abundant scaffold proteins, contains five domains: PDZ1, PDZ2, PDZ3, Src homology 3 (SH3), and guanylate kinase-like (GK) domain. The domains are functionally divided in two supramodules: PDZ1-PDZ2 and PDZ3-SH3-GK (PSG). Multi-domain proteins are characterized through their isolated domains in most studies and represented by “beads on a string” model, which means that the function of a single domain is independent of the context. In this thesis, the properties of PDZ3 and PSG are compared to elucidate how and when PSD-95 can been characterized by the simple “beads on a string” model. Kinetic characterization of CRIPT binding to PDZ3 showed a two-state mechanism, but a more complex mechanism involving two conformational states upon binding to PSG. The results were consistent with recent structural findings of conformational changes in PSD-95, altogether showing that conformational transitions in supertertiary structures can shape the ligand-binding energy landscape and modulate protein-protein interactions. Next the allosteric networks in a PDZ:ligand complex were experimentally mapped, both in isolation and in the context of a supramodular structure. Data showed that allosteric networks in a PDZ3 domain has high dependency on the supertertiary structure. Furthermore, equilibrium and kinetic folding experiments were applied to demonstrate that the PDZ3 domain folds faster and independently from the SH3-GK tandem, which folds as one cooperative unit. However, concurrent folding of the PDZ3 domain slows down folding of SH3-GK by non-native interactions, resulting in an off-pathway folding intermediate. Finally, the interactome of PSG in PSD was mapped. PDZ3 and PSG show high specificity for peptides with type I PBM. Interestingly, two proteins called SynGap and AGRB1 only bind with high affinity to PSG and forms concentration dependent liquid droplets. The results show how context in terms of supertertiary structure alter affinity and function, and suggest a model for how PSD anchor to the postsynaptic membrane. Altogether, the findings in the thesis show that binding energy landscape, interactome, allosteric network, folding mechanism and phase separation are dependent on the context, which suggest that we need to be careful in interpretation of data obtained from isolated domains in multi-domain proteins.
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