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| 2. |
- Saénz-de la O, Diana, et al.
(författare)
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Antioxidant and drought‑acclimation responses in UV‑B‑exposed transgenic Nicotiana tabacum displaying constitutive overproduction of H2O2
- 2023
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Ingår i: Photochemical and Photobiological Sciences. - : Springer. - 1474-905X .- 1474-9092. ; 22:10, s. 2373-2387
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen peroxide (H2O2) is an important molecule that regulates antioxidant responses that are crucial for plant stress resistance. Exposure to low levels of ultraviolet-B radiation (UV-B, 280–315 nm) can also activate antioxidant defenses and acclimation responses. However, how H2O2 and UV-B interact to promote stress acclimation remains poorly understood. In this work, a transgenic model of Nicotiana tabacum cv Xanthi nc, with elevated Mn-superoxide dismutase (Mn-SOD)activity, was used to study the interaction between the constitutive overproduction of H2O2 and a 14-day UV-B treatment (1.75 kJ m−2 d−1 biologically effective UV-B). Subsequently, these plants were subjected to a 7-day moderate drought treatment to evaluate the impact on drought resistance of H2O2- and UV-dependent stimulation of the plants' antioxidant system. The UV-B treatment enhanced H2O2 levels and altered the antioxidant status by increasing the epidermal flavonol index, Trolox Equivalent Antioxidant Capacity, and catalase, peroxidase and phenylalanine ammonia lyase activities in the leaves. UV-B also retarded growth and suppressed acclimation responses in highly H2O2-overproducing transgenic plants. Plants not exposed to UV-B had a higher drought resistance in the form of higher relative water content of leaves. Our data associate the interaction between Mn-SOD transgene overexpression and the UV-B treatment with a stress response. Finally, we propose a hormetic biphasic drought resistance response curve as a function of leaf H2O2 content in N. tabacum cv Xanthi.
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| 3. |
- Kalbina, Irina, et al.
(författare)
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Two separate UV-B radiation wavelength regions control expression of different molecular markers in Arabidopsis thaliana
- 2008
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Ingår i: Functional Plant Biology. - Collinwood VIC : CSIRO. - 1445-4408 .- 1445-4416. ; 35:3, s. 222-227
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Tidskriftsartikel (refereegranskat)abstract
- Fluence-response curves were obtained at nine wavelengths in the interval 280-360 nm for mRNA transcripts of four molecular markers induced by ultraviolet-B (UV-B) radiation in Arabidopsis thaliana: CHS (encoding chalcone synthase), PDX1.3 (encoding an enzyme involved in formation of pyridoxine), MEB5.2 (encoding a protein with unknown function but which is strongly up-regulated by UV-B), and LHCB1*3 (encoding a chlorophyll a/b binding protein). Intact Arabidopsis plants were irradiated for 3h using a high intensity deuterium radiation source and narrow bandwith filters (Kalbin et al. 2005, J. Biochem. Biophys. Meth. 65, 1-12) without supplementary PAR. The results obtained suggest the existence of two distinct UV-B signal responses: one sensitive between 300 and 310 nm and the other sensitive around 280-290 nm. Among the investigated molecular markers, CHS and PDX1.3 were regulated through the chromophore absorbing around 300 nm, whereas MEB5.2 and LHCB1*3 were regulated through the chromophore absorbing at 280-290 nm. The results obtained show that at least two signal transduction pathways exist that regulate gene expression as a result of absorption of UV-B radiation in plants.
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| 4. |
- Sorour, Ashraf E., et al.
(författare)
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Evaluation of hepatocyte growth factor as a local acute phase response marker in the bowel : the clinical impact of a rapid diagnostic test for immediate identification of acute bowel inflammation
- 2015
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Ingår i: Cytokine. - : Elsevier BV. - 1043-4666 .- 1096-0023. ; 71:1, s. 8-15
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Tidskriftsartikel (refereegranskat)abstract
- Background: There are no rapid tests that can distinguish contagious gastroenteritis, which requires isolation at its onset, from exacerbation of chronic inflammatory bowel disease (IBD) or bowel engagement in the course of systemic inflammatory response syndrome (SIRS). Hepatocyte growth factor (HGF) is an acute phase cytokine that is produced at the site of injury. It has high affinity to sulfated glycan, and this binding affinity is lost during chronic inflammation. The fecal pH strongly impacts the prognosis for severe bowel disease. We developed a strip test to evaluate HGF as a local acute phase response marker in the bowel. This test assessed the binding affinity of HGF to sulfated glycans in fecal samples and determined fecal pH as an indicator of illness severity.Methods: Fresh feces from patients with diarrhea (n = 513) were collected and tested blindly, and information about patient illness course and outcome was collected. Patients were classified based on the focus of inflammation and the cause of the symptoms. Objectively verified diagnoses of infectious gastroenteritis (n = 131) and IBD onset/exacerbation and bowel cancer (n = 44) were used to estimate the performance of the test strip. ELISA was performed on 101 freeze-thawed feces samples to determine the fecal HGF levels.Results: The test rapidly distinguished infectious gastroenteritis from non-infectious inflammatory causes of diarrhea (sensitivity, 87.96%; specificity, 90.9%; positive predictive value, 96.6%; negative predictive value, 71.4%; accuracy, 89.1%). Fecal pH (p < 0.0001) and mortality within 28 days of sampling (p < 0.04) was higher in patients with sepsis/SIRS and diarrhea. The concentration of HGF was higher in strip test-positive stool samples (p < 0.01).Conclusions: HGF is a good local acute phase response marker of acute bowel inflammation. Test-strip determination of the binding affinity of fecal HGF to sulfated glycan was a rapid, equipment-free way to assess patients with diarrhea and to guide the diagnostic and therapeutic approaches on admission. (C) 2014 The Authors. Published by Elsevier Ltd.
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| 6. |
- Grahn, Elin M., 1970-, et al.
(författare)
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Structural Characterization of a Lectin from the Mushroom Marasmius oreades in Complex with the Blood Group B Trisaccharide and Calcium
- 2009
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Ingår i: Journal of Molecular Biology. - Amsterdam : Academic Press. - 0022-2836 .- 1089-8638. ; 390:3, s. 457-466
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Tidskriftsartikel (refereegranskat)abstract
- MOA (Marasmius oreades agglutinin), a lectin isolated from fruiting bodies of the mushroom M. oreades, specifically binds nonreducing terminal Galα(1,3)Gal carbohydrates, such as that which occurs in the xenotransplantation epitope Galα(1,3)Galβ(1,4)GlcNAc and the branched blood group B determinant Galα(1,3)[Fucα(1,2)]Gal. Here, we present the crystal structure of MOA in complex with the blood group B trisaccharide solved at 1.8 Å resolution. To our knowledge, this is the first blood-group-B-specific structure reported in complex with a blood group B determinant. The carbohydrate ligand binds to all three binding sites of the N-terminal β-trefoil domain. Also, in this work, Ca2+ was included in the crystals, and binding of Ca2+ to the MOA homodimer altered the conformation of the C-terminal domain by opening up the cleft containing a putative catalytic site.
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| 7. |
- Mohlin, Camilla, 1972-, et al.
(författare)
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Evaluation of Congo Red Staining in Degenerating Porcine Photoreceptors In Vitro : Protective Effects by Structural and Trophic Support
- 2018
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Ingår i: Journal of Histochemistry and Cytochemistry. - : Sage Publications. - 0022-1554 .- 1551-5044. ; 66:9
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Tidskriftsartikel (refereegranskat)abstract
- Congo red (CR) is a histological stain used for the detection of extracellular amyloids mediating various neurodegenerative diseases. Given that damaged photoreceptors appear to degenerate similarly to other nerve cells, CR staining was evaluated in experimentally injured porcine retina. CR staining appeared mostly as discrete cytosolic deposits with no obvious plaque formation during the investigated time period. Increases of CR labeling coincided temporally with the known accumulation of mislocalized opsins and increases of cell death. Coculture, either with human retinal pigment epithelium (ARPE) or human neural progenitor (ReN) cells, was accompanied by a significant reduction of CR labeling. Of particular interest was the reduction of CR labeling in cone photoreceptors, which are important for the perception of color and fine details and afflicted in age-related macular degeneration (AMD). Electron microscopy revealed inclusions in the inner segment, cell body, and occasionally synaptic terminals of photoreceptor cells in cultured specimens. Closer examinations indicated the presence of different types of inclusions resembling protein aggregates as well as inclusion bodies. The current results indicate that injury-related response resulted in accumulation of CR deposits in photoreceptor cells, and that trophic and/or structural support attenuated this response.
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| 8. |
- Hansson, Charlotta, et al.
(författare)
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Feeding transgenic plants that express a tolerogenic fusion protein effectively protects against arthritis
- 2016
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Ingår i: Plant Biotechnology Journal. - : Wiley-Blackwell. - 1467-7644 .- 1467-7652. ; 14:4, s. 1106-1115
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Tidskriftsartikel (refereegranskat)abstract
- Although much explored, oral tolerance for treatment of autoimmune diseases still awaits the establishment of novel and effective vectors. We investigated if the tolerogenic CTA1(R7K)-COL-DD fusion protein can be expressed in edible plants and in this way induce oral tolerance and protect against arthritis. The fusion protein was recombinantly expressed in Arabidopsis thaliana plants, which were fed to H-2q restricted DBA/1 mice to assess the preventive effect on collagen-induced arthritis (CIA). The treatment resulted in fewer mice exhibiting disease and arthritis scores were significantly reduced. Immune suppression was evident in treated mice and serum biomarkers for inflammation as well as anti-collagen IgG responses were reduced. In spleen draining and lymph nodes, CD4+ T cell responses were reduced. Concomitant with a reduced effector T cell activity with lower IFNg, IL-13 and IL-17A production we observed an increase in IL-10 production to recall antigen stimulation in vitro, suggesting reduced Th1, Th2 and Th17 activity subsequent to upregulated IL-10 and regulatory T cell (Treg) functions. The present study shows that edible plants expressing a tolerogen were effective at stimulating CD4 T cell tolerance and in protecting against CIA disease. Our study conveys optimism as to the potential of using edible plants for oral treatment of rheumatoid arthritis.
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| 9. |
- Asghar, Naveed, 1983-, et al.
(författare)
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Transient Expression of Flavivirus Structural Proteins in Nicotiana benthamiana
- 2022
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Ingår i: Vaccines. - : MDPI. - 2076-393X. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- Flaviviruses are a threat to public health and can cause major disease outbreaks. Tick-borne encephalitis (TBE) is caused by a flavivirus, and it is one of the most important causes of viral encephalitis in Europe and is on the rise in Sweden. As there is no antiviral treatment availa-ble, vaccination remains the best protective measure against TBE. Currently available TBE vaccines are based on formalin-inactivated virus produced in cell culture. These vaccines must be delivered by intramuscular injection, have a burdensome immunization schedule, and may exhibit vaccine failure in certain populations. This project aimed to develop an edible TBE vaccine to trigger a stronger immune response through oral delivery of viral antigens to mucosal surfaces. We demonstrated successful expression and post-translational processing of flavivirus structural pro-teins which then self-assembled to form virus-like particles in Nicotiana benthamiana. We performed oral toxicity tests in mice using various plant species as potential bioreactors and evaluated the immunogenicity of the resulting edible vaccine candidate. Mice immunized with the edible vaccine candidate did not survive challenge with TBE virus. Interestingly, immunization of female mice with a commercial TBE vaccine can protect their offspring against TBE virus infection.
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| 10. |
- Roomans, Godfried M., 1951-, et al.
(författare)
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X-Ray Microanalysis in the Scanning Electron Microscope
- 2014. - 3
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Ingår i: Electron microscopy. - New York, USA : Humana Press. - 9781627037761 - 9781627037754 ; , s. 639-661
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Bokkapitel (refereegranskat)abstract
- X-ray microanalysis conducted using the scanning electron microscope is a technique that allows the determination of chemical elements in bulk or semi-thick specimens. The lowest concentration of an element that can be detected is in the order of a few mmol/kg or a few hundred parts per million, and the smallest amount is in the order of 10(-18) g. The spatial resolution of the analysis depends on the thickness of the specimen. For biological specimen analysis, care must be taken to prevent displacement/loss of the element of interest (usually ions). Protocols are presented for the processing of frozen-hydrated and freeze-dried specimens, as well as for the analysis of small volumes of fluid, cell cultures, and other specimens. Aspects of qualitative and quantitative analysis are covered, including limitations of the technique.
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