umu.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1 - 16 av 16
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Hasslöf, Pamela
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Twetman, Svante
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Growth inhibition of oral mutans streptococci and candida by commercial probiotic lactobacilli: an in vitro study2010Ingår i: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 10, s. 18-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The selected probiotic strains showed a significant but somewhat varying ability to inhibit growth of oral mutans streptococci and Candida albicans in vitro.

  • 2.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Growth inhibition of Porphyromonas gingivalis biofilm by lactobacilli2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Background. Chronic periodontitis is one of the most common infectious diseases of the oral cavity. Dental plaque contains a mix of oral bacteria, and grows as biofilm on tooth surfaces. One of the bacterial species associated with periodontitis is Porphyromonas gingivalis, a Gram-negative anaerobic rod. Lactobacilli are used in probiotic products and are known to play an important role in the management of health by stimulating the immune system and contributing to the balance of the normal microflora. The knowledge of probiotic effects on oral bacteria is at present limited.

    Purpose. Lactobacillus reuteri, and Lactobacillus acidophilus are two species used in different probiotic products. In the presence of glycerol L. reuteri produces an antimicrobial product, 3-hydroxypropionaldehyd, also called reuterin. The purpose of the study was to examine the impact of L. reuteri and L. acidophilus on biofilm formed by P. gingivalis.

    Methods. To study whether L. reuteri and L. acidophilus had ability to alter the biofilm formation of P. gingivalis, 108 CFU/mL P. gingivalis and 108 CFU/mL of one of the lactobacilli were co-cultured in Brucella broth using cell-culture plates. After 48 h incubation the broth was removed and the biofilm studied by microscopy, crystal violet staining with subsequent absorbance measurements at 590 nm. Viable bacterial cells were determined in the biofilm and in the removed growth medium.

    Results. P. gingivalis and L. reuteri cultured individually formed heavy layers of biofilm (A590=2.1-3.1), whereas L. acidophilus gave a very thin layer (A590=0.21-0.35). In the biofilm competition assay, the level of viable P. gingivalis cells were reduced by at least 3 logs regardless the addition of glycerol when co-cultured with L. reuteri or L. acidophilus. In presence of glycerol, both P. gingivalis and L. reuteri were reduced below the detection level after 48 h incubation.

    Even though P. gingivalis cultured as single species formed a dense biofilm this was strongly reduced when co-cultured with L. acidophilus.

    Conclusion. In summary, the observed glycerol-dependent growth inhibition of P. gingivalis by L. reuteri seemed to be due to reuterin production. Competition in the biofilm model appeared to favor both lactobacillus species tested at the expense of P. gingivalis. The lactobacilli were able to strongly inhibit or suppress the growth of a major periodontal pathogen in the biofilm-competition assay.

  • 3.
    Hedberg, Maria E.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Israelsson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Moore, Edward R. B.
    Svensson-Stadler, Liselott
    Wai, Sun Nyunt
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Pietz, Grzegorz
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sandström, Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarstrom, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Prevotella jejuni sp nov., isolated from the small intestine of a child with coeliac disease2013Ingår i: International Journal of Systematic and Evolutionary Microbiology, ISSN 1466-5026, E-ISSN 1466-5034, Vol. 63, nr 11, s. 4218-4223Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Five obligately anaerobic, Gram-stain-negative, saccharolytic and proteolytic, non-spore-forming bacilli (strains CD3 :27, CD3 :28(T), CD3 :33, CD3 :32 and CD3 :34) are described. All five strains were isolated from the small intestine of a female child with coeliac disease. Cells of the five strains were short rods or coccoid cells with longer filamentous forms seen sporadically. The organisms produced acetic acid and succinic acid as major metabolic end products. Phylogenetic analysis based on comparative 16S rRNA gene sequence analysis revealed close relationships between CD3 : 27, CD3 :28(T) and CD3 :33, between CD3 :32 and Prevotella histicola CCUG 55407(T), and between CD3 :34 and Prevotella melaninogenica CCUG 4944B(T). Strains CD3 : 27, CD3 :28(T) and CD3 :33 were clearly different from all recognized species within the genus Prevotella and related most closely to but distinct from P. melaninogenica. Based on 16S rRNA, RNA polymerase) beta-subunit (rpoB) and 60 kDa chaperonin protein subunit (cpn60) gene sequencing, and phenotypic, chemical and biochemical properties, strains CD3 :27, CD3 :28(T) and CD3 :33 are considered to represent a novel species within the genus Prevotella, for which the name Prevotella jejuni sp. nov. is proposed. Strain CD3 : 28(T) (=CCUG 60371(T)=DSM 26989(T)) is the type strain of the proposed novel species. All five strains were able to form homologous aggregates, in which tube-like structures were connecting individual bacteria cells. The five strains were able to bind to human intestinal carcinoma cell lines at 37 degrees C.

    Ladda ner fulltext (pdf)
    fulltext
  • 4.
    Hedberg, Maria E
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Moore, Edward RB
    Svensson-Stadler, Liselott
    Hörstedt, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Baranov, Vladimir
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk immunologi.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Wai, Sun Nyunt
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    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.2012Ingår i: International Journal of Systematic and Evolutionary Microbiology, ISSN 1466-5026, E-ISSN 1466-5034, Vol. 62, nr 11, s. 2685-2690Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 5.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Baranov, Vladimir
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk immunologi.
    Wai, Sun Nyunt
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Moore, Edward
    Sahlgrenska Universitetssjukhuset, Göteborgs Universitet.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Clostridiales bacterium CD3:22-an anaerobic spore-forming bacterium isolated from small intestine in a celiac disease patient2010Rapport (Övrigt vetenskapligt)
  • 6.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Hasslöf, Pamela
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Sjöström, I
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Twetman, S
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Pedodonti.
    Sugar fermentation in probiotic bacteria: an in vitro study2008Ingår i: Oral Microbiology and Immunology, ISSN 0902-0055, E-ISSN 1399-302X, Vol. 23, nr 6, s. 482-485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    INTRODUCTION: Food supplemented with probiotic bacteria is a rapidly growing sector of the market. The aim of the present study was to evaluate and compare the acid production of selected probiotic strains available in commercial products.

    METHODS: Six Lactobacillus strains (Lactobacillus plantarum 299v and 931; Lactobacillus rhamnosus GG and LB21; Lactobacillus paracasei subsp. paracasei F19, and Lactobacillus reuteri PTA 5289) were cultivated at 37 degrees C in an anaerobic atmosphere on Man, Rogosa, Shape (MRS) agar for 48 h or MRS broth for 16 h. After centrifugation, the cells were washed and resuspended in sterile phosphate-buffered saline and immediately subjected to a fermentation assay with 12 different carbohydrates (nine sugars and three sugar alcohols) in microtiter plates with a pH indicator. The plates were examined for color changes after 24, 48, and 72 h of incubation under aerobic and anaerobic conditions. Three scores were used: negative (pH > 6.8); weak (pH 5.2-6.8), and positive (pH < 5.2). The strains were characterized with the API 50 CH system to confirm their identity.

    RESULTS: L. plantarum fermented all the sugars except for melibiose, raffinose, and xylitol. Both L. rhamnosus strains were generally less active although L. rhamnosus GG was slightly more active than strain LB21 in the 5% CO(2) setting. The latter strain exhibited negative reactions for sucrose, maltose, arabinose, and sorbitol under anaerobic conditions. The assays with L. paracasei and L. reuteri had negative or weak reactions for all tested sugars under both aerobic and anaerobic conditions.

    CONCLUSION: The metabolic capacity to form acid from dietary sugars differed significantly between the various probiotic strains.

  • 7.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Hasslöf, Pamela
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Sjöström, Inger
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Stecksén-Blicks, Christina
    Umeå universitet, Medicinsk fakultet, Odontologi, Pedodonti.
    Twetman, Svante
    University of Copenhagen.
    In vitro inhibition of mutans streptococci by probiotic lactobacilli2009Rapport (Övrigt vetenskapligt)
  • 8.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Karched, Maribasappa
    Asikainen, Sirkka
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    In-vitro growth inhibition of periodontitis-associated species by Lactobacillus reuteri2006Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Purpose. Lactobacillus reuteri, a species used in probiotic products, produces in vitro a bacteriocin, reuterin, in the presence of glycerol. The purpose of the study was to investigate in vitro whether L. reuteri strains inhibit the growth of periodontal pathogens.

    Methods. The inhibition study was based on a disk-diffusion method. The periodontitis-associated bacteria were pre-grown for 20 h in Brucella broth or Brucella blood agar at 37oC in anaerobic atmosphere. Standardization of bacterial inocula used in the assay was made by determinations of optical density, microscopic counting of cells, and viable count. Brucella blood agar plates, without or with glycerol (100 mM), were seeded with standardized inocula of the periodontal pathogens Fusobacterium nucleatum (IDH 4186), Porphyromonas gingivalis (ATCC 33277), Prevotella intermedia (ATCC 25611), and Actinobacillus actinomycetemcomitans (SA 1398). The lactobacilli L. reuteri ATCC 55730 and L. reuteri PTA 5289 were grown for 16 h in MRS broth. A 20-L aliquot of the suspension containing 107 CFU/mL was used to soak 6-mm paper disks, which were placed on Brucella agar plates (diameter 14 cm), seeded with each periodontal pathogen separately. The plates were then incubated for 3 - 7 days in anaerobic atmosphere at 37oC before measuring the inhibition zones.

    Results. On Brucella blood agar plates seeded with periodontal pathogens, no inhibition zones were seen around the paper discs. When glycerol was added to the agar, zones of 26 to 118 mm appeared. Sizes of the zones depended on the L. reuteri strain, the periodontal pathogen, and the sizes of their inocula. L. reuteri PTA 5289 had a stronger (7-30%) inhibitory effect than L. reuteri ATCC 55730 on all periodontal species. P. gingivalis was the most susceptible species among the tested strains.

    Conclusion. Both L. reuteri strains strongly inhibited or suppressed the growth of the tested periodontitis-associated bacteria in the presence of glycerol. The inhibitory activity of L. reuteri PTA 5289 was consistently higher than that of L. reuteri ATCC 55730. The results suggest that the inhibition activity of the tested lactobacilli was related to reuterin.

  • 9.
    Hedberg, Maria
    et al.
    Umeå universitet, Medicinsk fakultet, Odontologi, Oral mikrobiologi.
    Nord, Carl Erik
    Karoloinska Institute,.
    Anaerobic bacteria2008Ingår i: Antimicrobial therapy and vaccines: volume I: Microbes, New York: Apple Trees Production, LLC , 2008, 3rdKapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 10.
    Ou, Gangwei
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hörstedt, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Patologi.
    Baranov, Vladimir
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Klinisk immunologi.
    Forsberg, Göte
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Drobni, Mirva
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Sandström, Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Wai, Sun Nyunt
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Johansson, Ingegerd
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Kariologi.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Proximal small intestinal microbiota and identification of rod-shaped bacteria associated with childhood celiac disease2009Ingår i: American Journal of Gastroenterology, ISSN 0002-9270, E-ISSN 1572-0241, Vol. 104, nr 12, s. 3058-3067Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVES: Alterations in the composition of the microbiota in the intestine may promote development of celiac disease (CD). Using scanning electron microscopy (SEM) we previously demonstrated that rod-shaped bacteria were present on the epithelium of proximal small intestine in children with CD but not in controls. In this study we characterize the microbiota of proximal small intestine in children with CD and controls and identify CD-associated rod-shaped bacteria. METHODS: Proximal small intestine biopsies from 45 children with CD and 18 clinical controls were studied. Bacteria were identified by 16S rDNA sequencing in DNA extracted from biopsies washed with buffer containing dithiothreitol to enrich bacteria adhering to the epithelial lining, by culture-based methods and by SEM and transmission electron microscopy. RESULTS: The normal, mucosa-associated microbiota of proximal small intestine was limited. It was dominated by the genera Streptococcus and Neisseria, and also contained Veillonella, Gemella, Actinomyces, Rothia, and Haemophilus. The proximal small intestine microbiota in biopsies from CD patients collected during 2004-2007 differed only marginally from that of controls, and only one biopsy (4%) had rod-shaped bacteria by SEM (SEM+). In nine frozen SEM+ CD biopsies from the previous study, microbiotas were significantly enriched in Clostridium, Prevotella, and Actinomyces compared with SEM- biopsies. Bacteria of all three genera were isolated from children born during the Swedish CD epidemic. New Clostridium and Prevotella species and Actinomyces graevenitzii were tentatively identified. CONCLUSIONS: Rod-shaped bacteria, probably of the indicated species, constituted a significant fraction of the proximal small intestine microbiota in children born during the Swedish CD epidemic and may have been an important risk factor for CD contributing to the fourfold increase in disease incidence in children below 2 years of age during that time.

  • 11.
    Pietz, Grzegorz
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    De, Rituparna
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sjöberg, Veronika
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sandström, Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Immunopathology of childhood celiac disease: Key role of intestinal epithelial cells2017Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, nr 9, artikel-id e0185025Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND & AIMS: Celiac disease is a chronic inflammatory disease of the small intestine mucosa due to permanent intolerance to dietary gluten. The aim was to elucidate the role of small intestinal epithelial cells in the immunopathology of celiac disease in particular the influence of celiac disease-associated bacteria.

    METHODS: Duodenal biopsies were collected from children with active celiac disease, treated celiac disease, and clinical controls. Intestinal epithelial cells were purified and analyzed for gene expression changes at the mRNA and protein levels. Two in vitro models for human intestinal epithelium, small intestinal enteroids and polarized tight monolayers, were utilized to assess how interferon-γ, interleukin-17A, celiac disease-associated bacteria and gluten influence intestinal epithelial cells.

    RESULTS: More than 25 defense-related genes, including IRF1, SPINK4, ITLN1, OAS2, CIITA, HLA-DMB, HLA-DOB, PSMB9, TAP1, BTN3A1, and CX3CL1, were significantly upregulated in intestinal epithelial cells at active celiac disease. Of these genes, 70% were upregulated by interferon-γ via the IRF1 pathway. Most interestingly, IRF1 was also upregulated by celiac disease-associated bacteria. The NLRP6/8 inflammasome yielding CASP1 and biologically active interleukin-18, which induces interferon-γ in intraepithelial lymphocytes, was expressed in intestinal epithelial cells.

    CONCLUSION: A key factor in the epithelial reaction in celiac disease appears to be over-expression of IRF1 that could be inherent and/or due to presence of undesirable microbes that act directly on IRF1. Dual activation of IRF1 and IRF1-regulated genes, both directly and via the interleukin-18 dependent inflammasome would drastically enhance the inflammatory response and lead to the pathological situation seen in active celiac disease.

    Ladda ner fulltext (pdf)
    fulltext
  • 12.
    Pietz, Grzegorz
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Israelsson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sandström, Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Nyunt Wai, Sun
    Umeå universitet, Medicinska fakulteten, Institutionen för molekylärbiologi (Medicinska fakulteten).
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Influences of celiac disease associated bacteria on functions of intestinal epithelium: an in vitro studyManuskript (preprint) (Övrigt vetenskapligt)
  • 13.
    Sjöberg, Veronika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Sandström, Olof
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hammarström, Sten
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Hernell, Olle
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Pediatrik.
    Hammarström, Marie-Louise
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Immunologi/immunkemi.
    Intestinal T-cell responses in celiac disease: impact of celiac disease associated bacteria2013Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, nr 1, s. e53414-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A hallmark of active celiac disease (CD), an inflammatory small-bowel enteropathy caused by permanent intolerance to gluten, is cytokine production by intestinal T lymphocytes. Prerequisites for contracting CD are that the individual carries the MHC class II alleles HLA-DQ2 and/or HLA-DQ8 and is exposed to gluten in the diet. Dysbiosis in the resident microbiota has been suggested to be another risk factor for CD. In fact, rod shaped bacteria adhering to the small intestinal mucosa were frequently seen in patients with CD during the "Swedish CD epidemic" and bacterial candidates could later be isolated from patients born during the epidemic suggesting long-lasting changes in the gut microbiota. Interleukin-17A (IL-17A) plays a role in both inflammation and anti-bacterial responses. In active CD IL-17A was produced by both CD8(+) T cells (Tc17) and CD4(+) T cells (Th17), with intraepithelial Tc17 cells being the dominant producers. Gluten peptides as well as CD associated bacteria induced IL-17A responses in ex vivo challenged biopsies from patients with inactive CD. The IL-17A response was suppressed in patients born during the epidemic when a mixture of CD associated bacteria was added to gluten, while the reverse was the case in patients born after the epidemic. Under these conditions Th17 cells were the dominant producers. Thus Tc17 and Th17 responses to gluten and bacteria seem to pave the way for the chronic disease with interferon-γ-production by intraepithelial Tc1 cells and lamina propria Th1 cells. The CD associated bacteria and the dysbiosis they might cause in the resident microbiota may be a risk factor for CD either by directly influencing the immune responses in the mucosa or by enhancing inflammatory responses to gluten.

    Ladda ner fulltext (pdf)
    fulltext
  • 14. Soki, Jozsef
    et al.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi, Biomedicinsk laboratorievetenskap.
    Patrick, Sheila
    Balint, Balazs
    Herczeg, Robert
    Nagy, Istvan
    Hecht, David W.
    Nagy, Elisabeth
    Urban, Edit
    Emergence and evolution of an international cluster of MDR Bacteroides fragilis isolates2016Ingår i: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 71, nr 9, s. 2441-2448Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to examine the antibiotic resistance profiles, antibiotic resistance mechanisms and possible 'clonal' nature of some MDR Bacteroides fragilis strains that simultaneously harboured cfiA, nimB, IS1186 and IS4351. Antibiotic susceptibilities were determined by Etests and antibiotic resistance genes and different genetic elements were detected by applying PCR methods. The environments of the cfiA and nimB genes were also determined by sequencing. The transferability of the cfiA, nimB and tet(Q) genes was tested by conjugation. The genetic relatedness of the test strains was tested by ERIC-PCR or PFGE. The complete genome sequences of two strains (B. fragilis BF8 and O:21) were determined by next-generation sequencing. Most of the seven B. fragilis strains tested displayed multidrug resistance phenotypes; five strains were resistant to at least five types of antibiotics. Besides the common genetic constitution, ERIC-PCR implied high genetic relatedness. Similarities in some of the antibiotic resistance mechanisms [carbapenems (cfiA) and metronidazole (nimB)] also confirmed their common origin, but some other resistance mechanisms {MLSB [erm(F)] and tetracycline [tet(Q)]} and PFGE typing revealed differences. In B. fragilis BF8 and O:21, erm(F) and tet(X) genes were found with IS4351 borders, thus constituting Tn4351. All the strains were tet(Q) positive and transferred this gene in conjugation experiments, but not the cfiA and nimB genes. An international cluster of MDR B. fragilis strains has been identified and characterized. This 'clone' may have emerged early in the evolution of division II B. fragilis strains, which was suggested by the low-complexity ERIC profiles and differences in the PFGE patterns.

  • 15.
    Sóki, J.
    et al.
    University of Szeged.
    Edwards, R.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Fang, H.
    Nagy, E.
    Nord, C. E.
    Examination of cfiA-mediated carbapenem resistance in Bacteroides fragilis strains from a European antibiotic susceptibility survey2006Ingår i: International Journal of Antimicrobial Agents, ISSN 0924-8579, E-ISSN 1872-7913, Vol. 28, nr 6, s. 497-502Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Of 1284 Bacteroides strains collected in Europe in 2000 for antibiotic susceptibility surveillance, 65 isolates displayed imipenem minimum inhibitory concentrations (MICs) > or =1 mg/L and were chosen for a thorough analysis of their resistance mechanism. Twenty-five of the isolates were positive for the cfiA carbapenem resistance gene. The resistance rates were 0.8% and 1.3% for imipenem and meropenem, respectively. In six of the strains, insertion sequence (IS) elements (IS613, IS614B, IS1186 and IS1187) activated the cfiA gene. However, other strains displayed at least elevated carbapenem MICs or were carbapenem resistant and produced measurable carbapenemase activities but did not harbour IS elements in the region upstream of the cfiA gene. The major determinant of carbapenem resistance in Bacteroides fragilis is production of CfiA metallo-beta-lactamase via activation of the cfiA gene by IS elements (higher level resistance) or by activation of its putative own promoter.

  • 16.
    Sóki, József
    et al.
    University of Szeged, Hungary.
    Hedberg, Maria
    Umeå universitet, Medicinska fakulteten, Institutionen för odontologi, Oral mikrobiologi.
    Urbán, Edith
    University of Szeged, Hungary.
    Terhes, G
    University of Szeged, Hungary.
    Nagy, Elisabeth
    University of Szeged, Hungary.
    Description of bacteroides strains showing hetero-resistance to cefoxitin and carbapenems2008Rapport (Övrigt vetenskapligt)
1 - 16 av 16
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf