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| 2. |
- Wehrli, Patrick M., et al.
(författare)
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Exploring bacterial phenotypic diversity using factorial design and FTIR multivariate fingerprinting
- 2014
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Ingår i: Journal of Chemometrics. - : John Wiley and Sons Ltd. - 0886-9383. ; 28:8, s. 681-686
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Tidskriftsartikel (refereegranskat)abstract
- Transmission Fourier transform infrared (FTIR) spectra were obtained from cultures of Staphylococcus aureus that were grown under sets of various environmental conditions enclosing ranges of potential conditions in wound sites. The primary aim of this study was to determine whether bacterial phenotypic diversity could be characterized by FTIR spectroscopy analyses of cultures of S.aureus grown under variable sets of environmental conditions. Designing experiments with full factorial design has shown to be a powerful way to explore an expectedly large array of phenotypic diversity of S.aureus. Various combinations of environmental conditions caused the bacteria to adapt their phenotype, which was assessed via FTIR spectral fingerprinting. Transmission FTIR spectroscopy was found to be superior to other vibrational spectroscopy techniques for this purpose because of its high sensitivity, reproducibility, and rapidity of analysis. The sample preparation presented was fundamental for reproducible results. Different spectral preprocessing methods were compared in combination with scaling methods to obtain distinguishable phenotypes in principal component analysis (PCA) models. Spectral preprocessing with combined filters, including standard normal variate transformation, Savitzky-Golay smoothing, and use of the first derivative in a PCA model with unit variance scaling, gave the most optimal clustering for the data in this study. Spectra obtained from each treatment group were found to have a unique FTIR profile with good reproducibility, and thus PCA resulted in full separation between all groups on three principal components. In conclusion, transmission FTIR spectroscopy in conjunction with design of experiment, and multivariate analysis are powerful tools to investigate phenotypic diversity of S.aureus. © 2014 John Wiley & Sons, Ltd.
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| 3. |
- Bankvall, Maria, et al.
(författare)
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The oral microbiota of patients with recurrent aphthous stomatitis.
- 2014
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Ingår i: Journal of oral microbiology. - : Informa UK Limited. - 2000-2297. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Specific pathogenic bacteria have been implicated in recurrent aphthous stomatitis (RAS), a chronic inflammatory condition characterised by ulcerations in the oral mucosa. However, the aetiology behind this condition still remains unclear.
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| 4. |
- Bergersen, L H, et al.
(författare)
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Immunogold detection of L-glutamate and D-serine in small synaptic-like microvesicles in adult hippocampal astrocytes.
- 2012
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 22:7, s. 1690-1697
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Tidskriftsartikel (refereegranskat)abstract
- Glutamate and the N-methyl-D-aspartate receptor ligand D-serine are putative gliotransmitters. Here, we show by immunogold cytochemistry of the adult hippocampus that glutamate and D-serine accumulate in synaptic-like microvesicles (SLMVs) in the perisynaptic processes of astrocytes. The estimated concentration of fixed glutamate in the astrocytic SLMVs is comparable to that in synaptic vesicles of excitatory nerve terminals (≈ 45 and ≈ 55 mM, respectively), whereas the D-serine level is about 6 mM. The vesicles are organized in small spaced clusters located near the astrocytic plasma membrane. Endoplasmic reticulum is regularly found in close vicinity to SLMVs, suggesting that astrocytes contain functional nanodomains, where a local Ca(2+) increase can trigger release of glutamate and/or D-serine.
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| 5. |
- Johansson, Sara, 1977, et al.
(författare)
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Long-chain polyunsaturated fatty acids are consumed during allergic inflammation and affect T helper type 1 (Th1)- and Th2-mediated hypersensitivity differently
- 2010
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Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 160:3, s. 411-419
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Tidskriftsartikel (refereegranskat)abstract
- P>Studies have shown that atopic individuals have decreased serum levels of n-3 fatty acids. Indicating these compounds may have a protective effect against allergic reaction and/or are consumed during inflammation. This study investigated whether fish (n-3) or sunflower (n-6) oil supplementation affected T helper type 1 (Th1)- and Th2-mediated hypersensitivity in the skin and airways, respectively, and whether the fatty acid serum profile changed during the inflammatory response. Mice were fed regular chow, chow + 10% fish oil or chow + 10% sunflower oil. Mice were immunized with ovalbumin (OVA) resolved in Th1 or Th2 adjuvant. For Th1 hypersensitivity, mice were challenged with OVA in the footpad. Footpad swelling, OVA-induced lymphocyte proliferation and cytokine production in the draining lymph node were evaluated. In the airway hypersensitivity model (Th2), mice were challenged intranasally with OVA and the resulting serum immunoglobulin (Ig)E and eosinophilic lung infiltration were measured. In the Th1 model, OVA-specific T cells proliferated less and produced less interferon (IFN)-gamma, tumour necrosis factor (TNF) and interleukin (IL)-6 in fish oil-fed mice versus controls. Footpad swelling was reduced marginally. In contrast, mice fed fish oil in the Th2 model produced more OVA-specific IgE and had slightly higher proportions of eosinophils in lung infiltrate. A significant fall in serum levels of long-chain n-3 fatty acids accompanied challenge and Th2-mediated inflammation in Th2 model. Fish oil supplementation affects Th1 and Th2 immune responses conversely; significant consumption of n-3 fatty acids occurs during Th2-driven inflammation. The latter observation may explain the association between Th2-mediated inflammation and low serum levels of n-3 fatty acids.
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| 7. |
- Stern, Anna, 1980, et al.
(författare)
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Neonatal Mucosal Immune Stimulation by Microbial Superantigen Improves the Tolerogenic Capacity of CD103(+) Dendritic Cells
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9
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Tidskriftsartikel (refereegranskat)abstract
- Food allergy represents failure to develop tolerance to dietary proteins. Food allergy has increased in prevalence in parallel with decreased exposure to microbes during infancy. In mice, neonatal peroral exposure to the strongly T cell stimulating superantigen staphylococcal enterotoxin A (SEA), enhances the capacity to develop oral tolerance to a novel antigen encountered in adult life. A population of antigen-presenting cells in the gut, the CD103(+) dendritic cells (DCs), is thought to be involved in oral tolerance development, as they convert naive T cells into FoxP3(+) regulatory T cells (Treg). This function depends on their capacity to convert vitamin A to retinoic acid, carried out by the retinal aldehyde dehydrogenase (RALDH) enzyme. Here, newborn mice were treated with superantigen and DC function and tolerogenic capacity was examined at six weeks of age. We observed that, in mice fed superantigen neonatally, the CD11c(+) DCs had increased expression of RALDH and in vitro more efficiently induced expression Foxp3 expression to stimulated T cells. Further, these mice showed an accumulation of FoxP3(+) T cells in the small intestinal lamina propria and had a more Ag-specific FoxP3(+) T cells after oral tolerance induction in vivo. Moreover, the improved oral tolerance, as shown by increased protection from food allergy, was eradicated if the Vitamin A metabolism was inhibited. These observations contribute to the understanding of how a strong immune stimulation during the neonatal period influences the maturation of the immune system and suggests that such stimulation may reduce the risk of later allergy development.
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| 8. |
- Wehrli, Patrick M., et al.
(författare)
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Maximising the potential for bacterial phenotyping using time‐of‐flight secondary ion mass spectrometry with multivariate analysis and Tandem Mass Spectrometry
- 2014
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Ingår i: Surface and Interface Analysis. - : Wiley. - 1096-9918 .- 0142-2421. ; 46:1, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- The increasing trend towards bacteria becoming resistant to current antibiotic treatments is of great concern to the healthcare industry with severe potential consequences for society as a whole. In many cases, it is the interaction of the antibacterial agent with the targets within the bacterial envelope of the microorganism that is a critical factor. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is uniquely capable of probing the chemistry in this region. This study aimed at optimising sample preparation and data pre-processing for bacterial analysis with ToF-SIMS and principal components analysis to study small chemical differences related to changes in bacterial phenotype that will help to find new antibiotics and understand how antibiotics are trafficked in the bacteria. ToF-SIMS analysis was performed using a J105 instrument equipped with a 40 kV C60+ ion source. Combination of positive and negative ion mode data enhanced the multivariate model quality regarding classification and aided chemical identification particularly when coupled with tandem mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.
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