| 1. |
- Andersson, Mats X., 1977, et al.
(författare)
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Involvement of the Electrophilic Isothiocyanate Sulforaphane in Arabidopsis Local Defense Responses
- 2015
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 167:1
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Tidskriftsartikel (refereegranskat)abstract
- Plants defend themselves against microbial pathogens through a range of highly sophisticated and integrated molecular systems. Recognition of pathogen-secreted effector proteins often triggers the hypersensitive response (HR), a complex multicellular defense reaction where programmed cell death of cells surrounding the primary site of infection is a prominent feature. Even though the HR was described almost a century ago, cell-to-cell factors acting at the local level generating the full defense reaction have remained obscure. In this study, we sought to identify diffusible molecules produced during the HR that could induce cell death in naive tissue. We found that 4-methylsulfinylbutyl isothiocyanate (sulforaphane) is released by Arabidopsis (Arabidopsis thaliana) leaf tissue undergoing the HR and that this compound induces cell death as well as primes defense in naive tissue. Two different mutants impaired in the pathogen-induced accumulation of sulforaphane displayed attenuated programmed cell death upon bacterial and oomycete effector recognition as well as decreased resistance to several isolates of the plant pathogen Hyaloperonospora arabidopsidis. Treatment with sulforaphane provided protection against a virulent H. arabidopsidis isolate. Glucosinolate breakdown products are recognized as antifeeding compounds toward insects and recently also as intracellular signaling and bacteriostatic molecules in Arabidopsis. The data presented here indicate that these compounds also trigger local defense responses in Arabidopsis tissue.
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| 2. |
- Andersson, Mats X., 1977, et al.
(författare)
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Oxylipin profiling of the hypersensitive response in Arabidopsis thaliana - Formation of a novel oxo-phytodienoic acid-containing galactolipid, arabidopside E
- 2006
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Ingår i: JOURNAL OF BIOLOGICAL CHEMISTRY. - 0021-9258. ; 281:42, s. 31528-31537
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation products of unsaturated fatty acids, collectively known as oxylipins, function as signaling molecules in plants during development, wounding, and insect and pathogen attack. Certain oxylipins are also known to have direct cytotoxic effects on pathogens. We used inducible expression of bacterial avirulence proteins in planta to study the involvement of oxylipins in race-specific defense against bacterial pathogens. We demonstrate that recognition of the Pseudomonas syringae avirulence protein AvrRpm1 induces 9- and 13-lipoxygenase-dependent oxylipin synthesis in Arabidopsis thaliana. The major oxylipins accumulated were jasmonic acid, 12-oxo-phytodienoic acid, and dinor-oxo-phytodienoic acid. The majority of the newly formed oxylipins (> 90%) was found to be esterified to glycerolipids, whereby 12-oxo-phytodienoic acid and dinor-oxo-phytodienoic acid were found to be esterified to a novel galactolipid. The structure of the substance was determined as a monogalactosyldiacylglycerol containing two 12-oxo-phytodienoic acids and one dinor-oxo-phytodienoic acid acyl chain and was given the trivial name arabidopside E. This substance accumulated to surprisingly high levels, 7 - 8% of total lipid content, and was shown to inhibit growth of a bacterial pathogen in vitro. Arabidopside E was formed also after recognition of the avirulence protein AvrRpt2, suggesting that this could be a conserved feature of defense reactions against bacterial pathogens. In conclusion, the data presented suggest a role of enzymatically formed oxylipins, especially the octadecanoids and arabidopside E in race-specific resistance against bacterial pathogens.
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| 3. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 4. |
- Nilsson, Anders K., 1982, et al.
(författare)
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Acylated monogalactosyl diacylglycerol : prevalence in the plant kingdom and identification of an enzyme catalyzing galactolipid head group acylation in Arabidopsis thaliana
- 2015
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Ingår i: The Plant Journal. - : Wiley-Blackwell. - 0960-7412 .- 1365-313X. ; 84:6, s. 1152-1166
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Tidskriftsartikel (refereegranskat)abstract
- The lipid phase of the thylakoid membrane is mainly composed of the galactolipids mono-and digalactosyl diacylglycerol (MGDG and DGDG, respectively). It has been known since the late 1960s that MGDG can be acylated with a third fatty acid to the galactose head group (acyl-MGDG) in plant leaf homogenates. In certain brassicaceous plants like Arabidopsis thaliana, the acyl-MGDG frequently incorporates oxidized fatty acids in the form of the jasmonic acid precursor 12-oxo-phytodienoic acid (OPDA). In the present study we further investigated the distribution of acylated and OPDA-containing galactolipids in the plant kingdom. While acyl-MGDG was found to be ubiquitous in green tissue of plants ranging from non-vascular plants to angiosperms, OPDA-containing galactolipids were only present in plants from a few genera. A candidate protein responsible for the acyl transfer was identified in Avena sativa (oat) leaf tissue using biochemical fractionation and proteomics. Knockout of the orthologous gene in A. thaliana resulted in an almost total elimination of the ability to form both non-oxidized and OPDA-containing acyl-MGDG. In addition, heterologous expression of the A. thaliana gene in E. coli demonstrated that the protein catalyzed acylation of MGDG. We thus demonstrate that a phylogenetically conserved enzyme is responsible for the accumulation of acyl-MGDG in A. thaliana. The activity of this enzyme in vivo is strongly enhanced by freezing damage and the hypersensitive response.
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| 5. |
- Persson, Mats, 1987-, et al.
(författare)
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Upper limits of the photon fluence rate on CT detectors : case study on a commercial scanner
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: The highest photon fluence rate that a CT detector must be able to measure is animportant parameter. We calculate the maximum transmitted fluence rate in a commercial CT scanner as a function of patient size for standard head, chest and abdomen protocols.Method: We scanned an anthropomorphic phantom (Kyoto Kagaku PBU-60) with the reference CT protocols provided by AAPM on a GE LightSpeed VCT scanner and noted the tube currentapplied with the tube current modulation (TCM) system. By rescaling this tube current usingpublished measurements on the tube current modulation of a GE scanner we could estimate the tube current that these protocols would have resulted in for other patient sizes. An ECG gatedchest protocol was also simulated. Using measured dose rate profiles along the bowtie filters, wesimulated imaging of anonymized patient images with a range of sizes on a GE VCT scanner andcalculated the maximum transmitted fluence rate. In addition, the 99th and the 95th percentilesof the transmitted fluence rate distribution behind the patient are calculated and the effect of omitting projection lines passing just below the skin line is investigated.Results: The highest transmitted fluence rates on the detector for the AAPM reference protocolswith centered patients are found for head and chest images of small patients, with a maximumof 7.1 · 107 mm−2 s−1 for head and 9.6 · 107 mm−2 s−1 for chest. Miscentering the head by 50 mm downwards increases the maximum transmitted fluence rate to 3.9 · 108 mm−2 s−1 . The ECG gatedchest protocol gives fluence rates up to 2.3 · 108 − 2.4 · 108 mm−2 s−1 depending on miscentering.Conclusion: The fluence rate on a CT detector reaches 1 · 108 − 4 · 108 mm−2 s−1 in standardimaging protocols, with the highest rates occurring for ECG gated chest and miscentered headscans. These results will be useful to developers of CT detectors, in particular photon countingdetectors.
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| 6. |
- Persson, Mats, 1987-, et al.
(författare)
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Upper limits of the photon fluence rate on CT detectors : Case study on a commercial scanner
- 2016
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Ingår i: Medical physics (Lancaster). - : AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS. - 0094-2405. ; 43:7, s. 4398-4411
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The highest photon fluence rate that a computed tomography (CT) detector must be able to measure is an important parameter. The authors calculate the maximum transmitted fluence rate in a commercial CT scanner as a function of patient size for standard head, chest, and abdomen protocols. Methods: The authors scanned an anthropomorphic phantom (Kyoto Kagaku PBU-60) with the reference CT protocols provided by AAPM on a GE LightSpeed VCT scanner and noted the tube current applied with the tube current modulation (TCM) system. By rescaling this tube current using published measurements on the tube current modulation of a GE scanner [N. Keat, "CT scanner automatic exposure control systems," MHRA Evaluation Report 05016, ImPACT, London, UK, 2005], the authors could estimate the tube current that these protocols would have resulted in for other patient sizes. An ECG gated chest protocol was also simulated. Using measured dose rate profiles along the bowtie filters, the authors simulated imaging of anonymized patient images with a range of sizes on a GE VCT scanner and calculated the maximum transmitted fluence rate. In addition, the 99th and the 95th percentiles of the transmitted fluence rate distribution behind the patient are calculated and the effect of omitting projection lines passing just below the skin line is investigated. Results: The highest transmitted fluence rates on the detector for the AAPM reference protocols with centered patients are found for head images and for intermediate-sized chest images, both with a maximum of 3.4 . 10(8) mm(-2) s-1, at 949 mm distance from the source. Miscentering the head by 50 mm downward increases the maximum transmitted fluence rate to 5.7 . 10(8) mm(-2) s(-1). The ECG gated chest protocol gives fluence rates up to 2.3 . 10(8)-3.6 . 10(8) mm(-2) s(-1) depending on miscentering. Conclusions: The fluence rate on a CT detector reaches 3 . 10(8)-6 . 10(8) mm(-2) s(-1) in standard imaging protocols, with the highest rates occurring for ECG gated chest and miscentered head scans. These results will be useful to developers of CT detectors, in particular photon counting detectors. (C) 2016 American Association of Physicists in Medicine.
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| 7. |
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| 8. |
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| 9. |
- Abdollahi Sani, Negar, et al.
(författare)
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All-printed diode operating at 1.6 GHz
- 2014
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 111:33, s. 11943-11948
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Tidskriftsartikel (refereegranskat)abstract
- Printed electronics are considered for wireless electronic tags and sensors within the future Internet-of-things (IoT) concept. As a consequence of the low charge carrier mobility of present printable organic and inorganic semiconductors, the operational frequency of printed rectifiers is not high enough to enable direct communication and powering between mobile phones and printed e-tags. Here, we report an all-printed diode operating up to 1.6 GHz. The device, based on two stacked layers of Si and NbSi2 particles, is manufactured on a flexible substrate at low temperature and in ambient atmosphere. The high charge carrier mobility of the Si microparticles allows device operation to occur in the charge injection-limited regime. The asymmetry of the oxide layers in the resulting device stack leads to rectification of tunneling current. Printed diodes were combined with antennas and electrochromic displays to form an all-printed e-tag. The harvested signal from a Global System for Mobile Communications mobile phone was used to update the display. Our findings demonstrate a new communication pathway for printed electronics within IoT applications.
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| 10. |
- Agredo Chavez, Angelica Maria, et al.
(författare)
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Cracking and Fatigue of Heavy Loaded Prestressed Concrete Bridge in Sweden
- 2022
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Ingår i: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering. - Zürich : International Association for Bridge and Structural Engineering. ; , s. 792-799
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Konferensbidrag (refereegranskat)abstract
- A prestressed concrete bridge was built in 1963 with BBRV cables. It has three spans and a total length of 134.8 m. Due to mining activities the bridge was loaded with trucks with a total weight of 90 ton during 2012-2014 and from 2019. Crack development has been monitored manually and from 2020 with strain gauges and LVDTs.Cracks normally vary between 0.1 to 0.3 mm in width and grow in length with time. In November 2020 some of the strain gauges on the concrete showed alarming growth and the bridge was closed for traffic. Additional strain gauges were installed on vertical reinforcement bars and an assessment was carried out of the fatigue capacity of the bridge. It was found that the new strain gauges did not indicate any growth in strain and that the fatigue capacity was sufficient. The bridge could be opened again for traffic after being closed for five weeks. Monitoring drift in the strain gauges and fatigue are discussed.
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