| 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. |
- Ekblom Bak, Elin, 1981-, et al.
(författare)
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Accelerometer derived physical activity patterns in 27.890 middle‐aged adults : The SCAPIS cohort study
- 2022
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 32:5, s. 866-880
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Tidskriftsartikel (refereegranskat)abstract
- The present study aims to describe accelerometer-assessed physical activity (PA) patterns and fulfillment of PA recommendations in a large sample of middle-aged men and women, and to study differences between subgroups of socio-demographic, socio-economic, and lifestyle-related variables. A total of 27 890 (92.5% of total participants, 52% women, aged 50–64 years) middle-aged men and women with at least four days of valid hip-worn accelerometer data (Actigraph GT3X+, wGT3X+ and wGT3X-BT) from the Swedish CArdioPulmonary bioImage Study, SCAPIS, were included. In total, 54.5% of daily wear time was spent sedentary, 39.1% in low, 5.4% in moderate, and only 0.1% in vigorous PA. Male sex, higher education, low financial strain, born in Sweden, and sedentary/light working situation were related to higher sedentary time, but also higher levels of vigorous PA. High BMI and having multiple chronic diseases associated strongly with higher sedentary time and less time in all three PA intensities. All-year physically active commuters had an overall more active PA pattern. The proportion fulfilling current PA recommendations varied substantially (1.4% to 92.2%) depending on data handling procedures and definition used. Twenty-eight percent was defined as having an “at-risk” behavior, which included both high sedentary time and low vigorous PA. In this large population-based sample, a majority of time was spent sedentary and only a fraction in vigorous PA, with clinically important variations between subgroups. This study provides important reference material and emphasizes the importance of a comprehensive assessment of all aspects of the individual PA pattern in future research and clinical practice.
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| 3. |
- Granlund, Anna, 1984-
(författare)
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Facilitating Automation Development in Internal Logistics Systems
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The internal logistics system includes all activities connected with managing the flow of materials within the physical limits of a facility. This system is an important part of operations in need of increased focus and continuous improvements. Automation is one possible tool with a previously confirmed great potential to improve internal logistics. Despite this great potential and a growing trend of using automation in the area, internal logistics activities are still not automated to the same extent as other parts of operations. The overall aim of this research is therefore to develop knowledge that supports the successful use of automation in internal logistics systems.The automation development process has been identified as critical for the success of the use of automation. With the overall aim of the research in mind, the objective of this thesis is to develop a framework facilitating the automation development process in internal logistics systems. To help fulfil the objective, empirical data have been collected through five case studies and a survey study. During the empirical studies, the process of improving the internal logistics system and the automation development process have been analysed and the focus has been on identifying challenges and facilitators for the successful use and development of automation in internal logistics systems.The findings indicate a poor awareness of both current and desired performance of the internal logistics system at the companies studied. In addition, automation development is often conducted in an unstructured and poorly supported manner and there is often insecurity regarding what steps and actions to take. Foremost, the findings indicate a poor base for proper evaluation and decisions during automation development in internal logistics systems. This is analysed and concluded as a cause of unclear goals and requirements and the lack of a strategic view with regard to both internal logistics operations and the use and development of automation.A framework, including proposed guidelines to overcome the observed challenges by including identified factors facilitating successful automation development in internal logistics systems has been developed. The core of the framework is a proposed process model for automation development in an internal logistics context. Due to the identified importance and the lack of a strategy linked to and supporting the automation development process, the framework also includes a proposed model for an internal logistics strategy as well as a proposed model for an automation strategy.
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| 4. |
- Johansson, Oskar N., 1984, et al.
(författare)
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A quick and robust method for quantification of the hypersensitive response in plants
- 2015
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Ingår i: Peerj. - : PeerJ. - 2167-8359. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- One of the most studied defense reactions of plants against microbial pathogens is the hypersensitive response (HR). The HR is a complex multicellular process that involves programmed cell death at the site of infection. A standard method to quantify plant defense and the HR is to measure the release of cellular electrolytes into water after infiltration with pathogenic bacteria. In this type of experiment, the bacteria are typically delivered into the plant tissue through syringe infiltration. Here we report the development of a vacuum infiltration protocol that allows multiple plant lines to be infiltrated simultaneously and assayed for defense responses. Vacuum infiltration did not induce more wounding response in Arabidopsis leaf tissue than syringe inoculation, whereas throughput and reproducibility were improved. The method was used to study HR-induced electrolyte loss after treatment with the bacterium Pseudomonas syringae pv. tomato DC3000 harboring the effector AvrRpm1, AvrRpt2 or AvrRps4. Specifically, the influence of bacterial titer on AvrRpm1-induced HR was investigated. Not only the amplitude, but also the timing of the maximum rate of the HR reaction was found to be dose-dependent. Finally, using vacuum infiltration, we were able quantify induction of phospholipase D activity after AvrRpm1 recognition in leaves labeled with (PO4)-P-33.
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| 5. |
- Johansson, Oskar N., 1984, et al.
(författare)
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Phenomics reveals a novel putative chloroplast fatty acid transporter in the marine diatom Skeletonema marinoi involved in temperature acclimation
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Diatoms are the dominant phytoplankton in temperate oceans and coastal regions and yet little is known about the genetic basis underpinning their global success. Here, we address this challenge by developing the first phenomic approach for a diatom, screening a collection of randomly mutagenized but identifiably tagged transformants. Based upon their tolerance to temperature extremes, several compromised mutants were identified revealing genes either stress related or encoding hypothetical proteins of unknown function. We reveal one of these hypothetical proteins is a novel putative chloroplast fatty acid transporter whose loss affects several fatty acids including the two omega-3, long-chain polyunsaturated fatty acids - eicosapentaenoic and docosahexaenoic acid, both of which have medical importance as dietary supplements and industrial significance in aquaculture and biofuels. This mutant phenotype not only provides new insights into the fatty acid biosynthetic pathways in diatoms but also highlights the future value of phenomics for revealing specific gene functions in these ecologically important phytoplankton.
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| 6. |
- Johansson, Oskar N., 1984, et al.
(författare)
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Redundancy among phospholipase D isoforrns in resistance triggered by recognition of the Pseudomonas syringae effector AyrRpm1 in Arabidopsis thaliana
- 2014
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Plants possess a highly sophisticated system for defense against microorganisms. So called MAMP (microbe-associated molecular patterns) triggered immunity (MTI) prevents the majority of non-adapted pathogens from causing disease. Adapted plant pathogens use secreted effector proteins to interfere with such signaling. Recognition of microbial effectors or their activity by plant resistance (R)-proteins triggers a second line of defense resulting in effector triggered immunity (ETI). The latter usually comprises the hypersensitive response (HR) which includes programmed cell death at the site of infection. Phospholipase D (PLD) mediated production of phosphatidic acid (PA) has been linked to both MTI and ETI in plants. Inhibition of PLD activity has been shown to attenuate MTI as well as ETI. In this study, we systematically tested single and double knockouts in all 12 genes encoding PLDs in Arabidopsis thaliana for effects on ETI and MTI. No single PLD could be linked to ETI triggered by recognition of effectors secreted by the bacterium Pseudomonas syringae. However, repression of PLD dependent PA production by n-butanol strongly inhibited the HR following Pseudomonas syringae effector recognition. In addition some p/d mutants were more sensitive to n-butanol than wild type. Thus, the effect of mutations of PLDs could become detectable, and the corresponding genes can be proposed to be involved in the HR. Only knockout of PLEA caused a loss of MTI-induced cell wall based defense against the non-host powdery mildew Erysiphe pisi. This is thus in stark contrast to the involvement of a multitude of PLD isoforms in the HR triggered by AvrRpm1 recognition.
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| 7. |
- Johansson Salazar-Sandoval, Eric, 1984-
(författare)
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Ceria Nanoparticle Hybrid Materials : Interfacial Design and Structure Control
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis addresses the challenge of bringing two very different materials into intimate chemical contact: inorganic metal oxide nanoparticles and acrylic polymers. In order to achieve this ambitious goal, the work has been divided into a series of more accessible tasks. Pedagogically designed, these tasks build upon one another to finally develop the knowledge and skills necessary to successfully formulate novel nanocomposites.A fundamental study on the bulk and surface bonding of ceria was carried out to show that, due to the ceria content in small and highly charged ions, which are difficult to polarize, the preferred chemical interactions are ionic. Among the different capping agents, the carboxylate ligands —through the rich and localized electron density of their oxygen atoms— formed an ionic bond with cerium oxides. This provided stability to the ceria nanoparticles and opened up a vast robust and versatile library of carboxylates to us. This is exemplified by the development of synthetic routes for understanding and modifying ceria nanoparticles with carboxylic acids carrying reactive moieties, which were used to extend the stability of the nanoparticle dispersions. This allowed us to perform in situ polymerization, which resulted in homogeneous ceria–polymer hybrid nanocomposites. This interfacial design offers not only structure control but also strong bonding between the covalent polymer network and the ionic nanocrystals.The focus of the present work, however, is not on characterization of the polymeric materials used but rather on how the embedded nanoparticles interact with the polymeric matrix with respect to chemical interfacial aspects. The following cases were studied: i) unreactive nanoceria dispersed in a polymer matrix; ii) dispersed nanoceria endowed with the ability to initiate polymerizations; and iii) dispersed nanoceria capable of copolymerizing with the propagating chains of the polymer.These processes led to the development of novel hybrid nanocomposites that preserved the optical properties of ceria (e.g. UV absorption) while enhancing mechanical properties such as stiffness and glass transition temperature.
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| 8. |
- Mazur, G. P., et al.
(författare)
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Towards modeling quasi-periodic oscillations of microquasars with oscillating slender tori
- 2013
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 554
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Tidskriftsartikel (refereegranskat)abstract
- Context. One of the often discussed models for high-frequency quasi-periodic oscillations of X-ray binaries is the oscillating torus model, which considers oscillation modes of slender accretion tori. Aims. Here, we aim at developing this model by considering the observable signature of an optically thick slender accretion torus subject to simple periodic deformations. Methods. We compute light curves and power spectra of a slender accretion torus subject to simple periodic deformations: vertical or radial translation, rotation, expansion, and shear. Results. We show that different types of deformations lead to very different Fourier power spectra and therefore could be observationally distinguished. Conclusions. This work is a first step in a longer term study of the observable characteristics of the oscillating torus model. It gives promising perspectives on the possibility of constraining this model by studying the observed power spectra of quasi-periodic oscillations.
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| 9. |
- Nilsson, Anders K., 1982, et al.
(författare)
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Formation of oxidized phosphatidylinositol and 12-oxo-phytodienoic acid containing acylated phosphatidylglycerol during the hypersensitive response in Arabidopsis
- 2014
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Ingår i: Phytochemistry. - : Elsevier BV. - 0031-9422. ; 101, s. 65-75
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Tidskriftsartikel (refereegranskat)abstract
- Plant membranes are composed of a wide array of polar lipids. The functionality of these extends far beyond a pure structural role. Membrane lipids function as enzyme co-factors, establish organelle identity and as substrates for enzymes such as lipases and lipoxygenases. Enzymatic degradation or oxidation (enzymatic or non-enzymatic) of membrane lipids leads to the formation of a diverse group of bioactive compounds. Plant defense reactions provoked by pathogenic microorganisms are often associated with substantial modifications of the lipidome. In this study, we profiled changes in phospholipids during the hypersensitive response triggered by recognition of the bacterial effector protein AvrRpm1 in Arabidopsis thaliana. A simple and robust LC-MS based method for profiling plant lipids was designed to separate all the major species of glycerolipids extracted from Arabidopsis leaf tissue. The method efficiently separated several isobaric and near isobaric lipid species, which otherwise are difficult to quantify in direct infusion based profiling. In addition to the previously reported OPDA-containing galactolipids found to be induced during hypersensitive response in Arabidopsis, three OPDA-containing sulfoquinovosyl diacylglycerol species, one phosphatidylinositol species as well as two acylated OPDA-containing phosphatidylglycerol species were found to accumulate during the hypersensitive response in Arabidopsis. Our study confirms and extends on the notion that the hypersensitive response in Arabidopsis triggers a unique profile of Allene Oxide Synthase dependent oxidation of membrane lipids. Primary targets of this oxidation seem to be uncharged and anionic lipid species. (C) 2014 Elsevier Ltd. All rights reserved.
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| 10. |
- Nilsson, Anders K., 1982, et al.
(författare)
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The activity of HYDROPEROXIDE LYASE 1 regulates accumulation of galactolipids containing 12-oxo-phytodienoic acid in Arabidopsis
- 2016
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 67:17, s. 5133-5144
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Tidskriftsartikel (refereegranskat)abstract
- Arabidopsis produces galactolipids containing esters of 12-oxo-phytodienoic acid (OPDA) and dinor-12-oxo-phytodienoic acid (dnOPDA). These lipids are referred to as arabidopsides and accumulate in response to abiotic and biotic stress. We explored the natural genetic variation found in 14 different Arabidopsis accessions to identify genes involved in the formation of arabidopsides. The accession C24 was identified as a poor accumulator of arabidopsides whereas the commonly used accession Col-0 was found to accumulate comparably large amounts of arabidopsides in response to tissue damage. A quantitative trait loci analysis of an F-2 population created from a cross between C24 and Col-0 located a region on chromosome four strongly linked to the capacity to form arabidopsides. Expression analysis of HYDROPEROXIDE LYASE 1 (HPL1) showed large differences in transcript abundance between accessions. Transformation of Col-0 plants with the C24 HPL1 allele under transcriptional regulation of the 35S promoter revealed a strong negative correlation between HPL1 expression and arabidopside accumulation after tissue damage, thereby strengthening the view that HPL1 competes with ALLENE OXIDE SYNTHASE (AOS) for lipid-bound hydroperoxide fatty acids. We further show that the last step in the synthesis of galactolipid-bound OPDA and dnOPDA from unstable allene oxides is exclusively enzyme-catalyzed and not the result of spontaneous cyclization. Thus, the results presented here together with previous studies suggest that all steps in arabidopside biosynthesis are enzyme-dependent and apparently all reactions can take place with substrates being esterified to galactolipids.
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