Change search
Refine search result
1234567 51 - 100 of 34676
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Abecasis, David
    et al.
    University of the Algarve, Portugal.
    Steckenreuter, Andre
    University of the Azores, Portugal.
    Reubens, Jan
    Flanders Marine Institute, Belgium.
    Aaestrup, Kim
    DTU, Denmark.
    Alos, Josep
    Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB), Spain.
    Badalamenti, Fabio
    CNR-IAMC, Italy.
    Bajona, Lenore
    Dalhousie University, Canada.
    Boylan, Patrick
    Loughs Agency, UK.
    Deneudt, Klaas
    Flanders Marine Institute, Belgium.
    Greenberg, Larry
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Brevé, Niels
    Sportfisserij Nederland, The Netherlands.
    Hernandez, Francisco
    Flanders Marine Institute, Belgium.
    Humphries, Nick
    The Marine Biological Association of the U.K, UK.
    Meyer, Carl
    University of Hawai’i at Mānoa, USA.
    Sims, David
    University of Southampton, UK.
    Thorstad, Eva B.
    Norwegian Institute for Nature Research (NINA), Norway.
    Walker, Alan M.
    Centre for Environment, Fisheries and Aquaculture Science (Cefas), UK.
    Whoriskey, Fred
    Dalhousie University, Canada.
    Alfonso, Pedro
    University of the Azores, Portugal.
    A review of acoustic telemetry in Europe and the need for a regional aquatic telemetry network2018In: Animal Biotelemetry, ISSN 2050-3385, E-ISSN 2050-3385, Vol. 6, p. 1-7, article id 12Article in journal (Refereed)
    Abstract [en]

    Background: Globally, there are a large and growing number of researchers using biotelemetry as a tool to studyaquatic animals. In Europe, this community lacks a formal network structure. The aim of this study is to review the useof acoustic telemetry in Europe and document the contribution of cross-boundary studies and inter-research groupcollaborations. Based on this, we explore the potential benefits and challenges of a network approach to identifyfuture priorities and best practices for aquatic biotelemetry research in Europe.

    Results: Over the past decade, there was an approximately sevenfold increase in the number of acoustic telemetrystudies published on marine and diadromous species in Europe compared to a sixfold increase globally. Over 90%of these studies were conducted on fishes and undertaken in coastal areas, estuaries, or rivers. 75% of these studieswere conducted by researchers based in one of five nations (Norway, UK, France, Portugal, and Spain) and, eventhough 34% were based on collaborations between scientists from several countries, there was only one study withan acoustic receiver array that extended beyond the borders of a single country. In recent years, acoustic telemetryin European waters has evolved from studying behavioural aspects of animals (82.2%), into more holistic approachesaddressing management-related issues (10%), tagging methods and effects (5%), and technology and data analysisdevelopment (2.8%).

    Conclusions: Despite the increasing number of publications and species tracked, there is a prominent lack ofplanned and structured acoustic telemetry collaborations in Europe. A formal pan-European network structure wouldpromote the development of (1) a research platform that could benefit the acoustic telemetry community throughcapacity building, (2) a centralized database, and (3) key deployment sites and studies on priority species requiringresearch in Europe. A network may increase efficiency, expand the scope of research that can be undertaken, promoteEuropean science integration, enhance the opportunities and success of acquiring research funding and, ultimately,foster regional and transatlantic collaborations. It may also help address research priorities such as the large-scalesocietal challenges arising from climate change impacts and assist the EU’s Marine Strategy Framework Directive viaidentification of good environmental status of endangered or commercially important species.

  • 52.
    Abedi-Valugerdi, Manuchehr
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Mercury and silver induce B cell activation and anti-nucleolar autoantibody production in outbred mouse stocks: are environmental factors more important than the susceptibility genes in connection with autoimmunity?2009In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 155, no 1, p. 117-124Article in journal (Refereed)
    Abstract [en]

    Environmental and predisposing genetic factors are known to play a crucial role in the development of systemic autoimmune diseases. With respect to the role of environmental factors, it is not known how and to what extent they contribute to the initiation and exacerbation of systemic autoimmunity. In the present study, I considered this issue and asked if environmental factors can induce autoimmunity in the absence of specific susceptible genes. The development of genetically controlled mercury- and silver-induced B cell activation and anti-nucleolar autoantibodies (ANolA) production in genetically heterozygous outbred Institute of Cancer Research (ICR), Naval Medical Research Institute (NMRI) and Black Swiss mouse stocks were analysed. Four weeks of treatment with both mercury and silver induced a strong B cell activation characterized by increased numbers of splenic antibody-secreting cells of at least one or more immunoglobulin (Ig) isotype(s) in all treated stocks. The three stocks also exhibited a marked increase in the serum IgE levels in response to mercury, but not silver. More importantly, in response to mercury a large numbers of ICR (88%), NMRI (96%) and Black Swiss (100%) mice produced different levels of IgG1 and IgG2a ANolA (a characteristic which is linked strictly to the H-2 genes). Similarly, but at lower magnitudes, treatment with silver also induced the production of IgG1 and IgG2a ANolA in 60% of ICR, 75% of NMRI and 100% of Black Swiss mice. Thus, the findings of this study suggest that long-term exposure to certain environmental factors can activate the immune system to produce autoimmunity per se, without requiring specific susceptible genes.

  • 53. Abel, John H.
    et al.
    Drawert, Brian
    Hellander, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computational Science.
    Petzold, Linda R.
    GillesPy: A Python package for stochastic model building and simulation2016In: IEEE Life Sciences Letters, E-ISSN 2332-7685, Vol. 2, p. 35-38Article in journal (Refereed)
  • 54.
    Abelein, Axel
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Modulation of Alzheimer's amyloid β peptide self-assembly: Insights into molecular mechanisms of peptide aggregation associated with Alzheimer's disease2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Misfolding of proteins and peptides is closely linked to several neurodegenerative disorders, among them Alzheimer's disease (AD), the most prominent example of brain diseases. The self-assembly of the amyloid β peptide (Aβ) into amyloid fibrils is one histologic hallmark of AD. A detailed knowledge about the underlying mechanism(s) of Aβ aggregation is crucial for advances toward a fundamental understanding of the disease, which may promote the search for and design of efficient therapeutics. The work presented in this thesis deals with modulation of the aggregation process by various compounds, i.e. small organic molecules (e.g. lacmoid and Congo red), surfactants and metal ions. These results provide insight into the molecular mechanism of modulator interactions and interference with Aβ and its aggregation pathways. Applying a combination of kinetic and dynamic studies as well as structural investigations we characterized the molecular interactions between Aβ and aggregation modulators in terms of microscopic rate constants, conformational preferences and thermodynamics. An important conclusion is that these modulators form highly dynamic complexes with Aβ, with life-times on the timescale of milliseconds. Despite the similar exchange dynamics, the effect on peptide aggregation is modulator-specific and fibril formation can be accelerated, retarded or inhibited by their interactions. In summary, Aβ self-assembly is governed by microscopic kinetic and dynamic processes that can be altered by aggregation modulators. Further elucidation of these mechanisms is beneficial for the understanding and therapeutic intervention of amyloid diseases.

  • 55.
    Abelein, Axel
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Modulation of amyloid β peptide self-assembly: Aggregation mechanisms associated with Alzheimer's disease2013Licentiate thesis, comprehensive summary (Other academic)
  • 56.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Abrahams, Jan Pieter
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Jarvet, Juri
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. National Institute of Chemical Physics and Biophysics, Estonia.
    Luo, Jinghui
    Tiiman, Ann
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Wärmländer, Sebastian K. T. S.
    The hairpin conformation of the amyloid beta peptide is an important structural motif along the aggregation pathway2014In: Journal of Biological Inorganic Chemistry, ISSN 0949-8257, E-ISSN 1432-1327, Vol. 19, no 4-5, p. 623-634Article, review/survey (Refereed)
    Abstract [en]

    The amyloid beta (A beta) peptides are 39-42 residue-long peptides found in the senile plaques in the brains of Alzheimer's disease (AD) patients. These peptides self-aggregate in aqueous solution, going from soluble and mainly unstructured monomers to insoluble ordered fibrils. The aggregation process(es) are strongly influenced by environmental conditions. Several lines of evidence indicate that the neurotoxic species are the intermediate oligomeric states appearing along the aggregation pathways. This minireview summarizes recent findings, mainly based on solution and solid-state NMR experiments and electron microscopy, which investigate the molecular structures and characteristics of the A beta peptides at different stages along the aggregation pathways. We conclude that a hairpin-like conformation constitutes a common motif for the A beta peptides in most of the described structures. There are certain variations in different hairpin conformations, for example regarding H-bonding partners, which could be one reason for the molecular heterogeneity observed in the aggregated systems. Interacting hairpins are the building blocks of the insoluble fibrils, again with variations in how hairpins are organized in the cross-section of the fibril, perpendicular to the fibril axis. The secondary structure propensities can be seen already in peptide monomers in solution. Unfortunately, detailed structural information about the intermediate oligomeric states is presently not available. In the review, special attention is given to metal ion interactions, particularly the binding constants and ligand structures of A beta complexes with Cu(II) and Zn(II), since these ions affect the aggregation process(es) and are considered to be involved in the molecular mechanisms underlying AD pathology.

  • 57.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Bolognesi, Benedetta
    Dobson, Christopher M.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lendel, Christofer
    Hydrophobicity and conformational change as mechanistic determinants for nonspecific modulators of amyloid β self-assembly2012In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 51, no 1, p. 126-137Article in journal (Refereed)
    Abstract [en]

    The link between many neurodegenerative disorders, including Alzheimer's and Parkinson's diseases, and the aberrant folding and aggregation of proteins has prompted a comprehensive search for small organic molecules that have the potential to inhibit such processes. Although many compounds have been reported to affect the formation of amyloid fibrils and/or other types of protein aggregates, the mechanisms by which they act are not well understood. A large number of compounds appear to act in a nonspecific way affecting several different amyloidogenic proteins. We describe here a detailed study of the mechanism of action of one representative compound, lacmoid, in the context of the inhibition of the aggregation of the amyloid β-peptide (Aβ) associated with Alzheimer's disease. We show that lacmoid binds Aβ(1-40) in a surfactant-like manner and counteracts the formation of all types of Aβ(1-40) and Aβ(1-42) aggregates. On the basis of these and previous findings, we are able to rationalize the molecular mechanisms of action of nonspecific modulators of protein self-assembly in terms of hydrophobic attraction and the conformational preferences of the polypeptide.

  • 58.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    The zinc ion – a minimal chaperone mimicking agent forretardation of amyloid β peptide fibril formationManuscript (preprint) (Other academic)
  • 59.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Zinc as chaperone-mimicking agent for retardation of amyloid beta peptide fibril formation2015In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 17, p. 5407-5412Article in journal (Refereed)
    Abstract [en]

    Metal ions have emerged to play a key role in the aggregation process of amyloid beta (A beta) peptide that is closely related to the pathogenesis of Alzheimer's disease. A detailed understanding of the underlying mechanistic process of peptide-metal interactions, however, has been challenging to obtain. By applying a combination of NMR relaxation dispersion and fluorescence kinetics methods we have investigated quantitatively the thermodynamic A beta-Zn2+ binding features as well as how Zn2+ modulates the nucleation mechanism of the aggregation process. Our results show that, under near-physiological conditions, substoichiometric amounts of Zn2+ effectively retard the generation of amyloid fibrils. A global kinetic profile analysis reveals that in the absence of zinc A beta(40) aggregation is driven by a monomer-dependent secondary nucleation process in addition to fibril-end elongation. In the presence of Zn2+, the elongation rate is reduced, resulting in reduction of the aggregation rate, but not a complete inhibition of amyloid formation. We show that Zn2+ transiently binds to residues in the N terminus of the monomeric peptide. A thermodynamic analysis supports a model where the N terminus is folded around the Zn2+ ion, forming a marginally stable, short-lived folded A beta(40) species. This conformation is highly dynamic and only a few percent of the peptide molecules adopt this structure at any given time point. Our findings suggest that the folded A beta(40)-Zn2+ complex modulates the fibril ends, where elongation takes place, which efficiently retards fibril formation. In this conceptual framework we propose that zinc adopts the role of a minimal antiaggregation chaperone for A beta(40).

  • 60.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Kaspersen, Jørn Døvling
    Nielsen, Søren Bang
    Jensen, Grethe Vestergaard
    Christiansen, Gunna
    Pedersen, Jan Skov
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Otzen, Daniel E.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Formation of dynamic soluble surfactant-induced amyloid β peptide aggregation intermediates2013In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 288, no 32, p. 23518-23528Article in journal (Refereed)
    Abstract [en]

    Intermediate amyloidogenic states along the amyloid β peptide (Aβ) aggregation pathway have been shown to be linked to neurotoxicity. To shed more light on the different structures that may arise during Aβ aggregation, we here investigate surfactant-induced Aβ aggregation. This process leads to co-aggregates featuring a β-structure motif that is characteristic for mature amyloid-like structures. Surfactants induce secondary structure in Aβ in a concentration-dependent manner, from predominantly random coil at low surfactant concentration, via β-structure to the fully formed α-helical state at high surfactant concentration. The β-rich state is the most aggregation-prone as monitored by thioflavin T fluorescence. Small angle x-ray scattering reveals initial globular structures of surfactant-Aβ co-aggregated oligomers and formation of elongated fibrils during a slow aggregation process. Alongside this slow (minutes to hours time scale) fibrillation process, much faster dynamic exchange (k(ex) ∼1100 s(-1)) takes place between free and co-aggregate-bound peptide. The two hydrophobic segments of the peptide are directly involved in the chemical exchange and interact with the hydrophobic part of the co-aggregates. Our findings suggest a model for surfactant-induced aggregation where free peptide and surfactant initially co-aggregate to dynamic globular oligomers and eventually form elongated fibrils. When interacting with β-structure promoting substances, such as surfactants, Aβ is kinetically driven toward an aggregation-prone state.

  • 61.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lang, Lisa
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lendel, Christofer
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Corrigendum to “Transient small molecule interactions kinetically modulate amyloid β peptide self-assembly” [FEBS Lett. 586 (2012) 3991–3995]2013In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 587, no 9, p. 1452-1452Article in journal (Other academic)
  • 62.
    Abelein, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lang, Lisa
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lendel, Christofer
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Danielsson, Jens
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Transient small molecule interactions kinetically modulate amyloid beta peptide self-assembly2012In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 586, no 22, p. 3991-3995Article in journal (Refereed)
    Abstract [en]

    Small organic molecules, like Congo red and lacmoid, have been shown to modulate the self-assembly of the amyloid beta peptide (A beta). Here, we show that A beta forms NMR invisible non-toxic co-aggregates together with lacmoid as well as Congo red. We find that the interaction involves two distinct kinetic processes and at every given time point only a small fraction of A beta is in the co-aggregate. These weak transient interactions kinetically redirect the aggregation prone A beta from self-assembling into amyloid fibrils. These findings suggest that even such weak binders might be effective as therapeutics against pathogenic protein aggregation.

  • 63. Abelein, Axel
    et al.
    Lang, Lisa
    Lendel, Christofer
    Gräslund, Astrid
    Danielsson, Jens
    Transient small molecule interactions kinetically modulate amyloid β peptide self-assembly.2012In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 586, no 22, p. 3991-3995, article id S0014-5793(12)00757-0Article in journal (Refereed)
    Abstract [en]

    Small organic molecules, like Congo red and lacmoid, have been shown to modulate the self-assembly of the amyloid β peptide (Aβ). Here, we show that Aβ forms NMR invisible non-toxic co-aggregates together with lacmoid as well as Congo red. We find that the interaction involves two distinct kinetic processes and at every given time point only a small fraction of Aβ is in the co-aggregate. These weak transient interactions kinetically redirect the aggregation prone Aβ from self-assembling into amyloid fibrils. These findings suggest that even such weak binders might be effective as therapeutics against pathogenic protein aggregation.

  • 64. Abeli, Thomas
    et al.
    Orsenigo, Simone
    Guzzon, Filippo
    Fae, Matteo
    Balestrazzi, Alma
    Carlsson-Graner, Ulla
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mueller, Jonas V.
    Mondoni, Andrea
    Geographical pattern in the response of the arctic-alpine Silene suecica (Cariophyllaceae) to the interaction between water availability and photoperiod2015In: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 30, no 2, p. 327-335Article in journal (Refereed)
    Abstract [en]

    We hypothesized a geographical pattern of the plant performance (seedling development, biomass production, relative water content and chlorophyll content) as a result of response to the interaction between photoperiod and water availability in populations of the arctic-alpine Silene suecica from different latitudes, thus experiencing different photoperiods during the growing season. Particularly, we expected a lower drought sensitivity in northern compared to southern populations as a consequence of harsher conditions experienced by the northern populations in terms of water availability. The experiment was carried out under common garden conditions, manipulating the water availability (wet and dry) and the photoperiod (21 and 16 h). We found an interaction between photoperiod and water availability on plant height, leaves, growth, biomass and total chlorophyll. However, the photoperiod neither counteracted nor intensified the effect of drought. Plants exposed to drought compensated for decreasing water availability by reducing their shoot growth. Changes in the chlorophyll content and chlorophyll a/b ratio were observed. Northern populations showed a higher basal growth performance and a greater response to the changed water regime (from wet to dry) than the southern populations. Southern populations showed a reduced ability to respond to drought, but their low basal performance may be advantageous under low water availability, avoiding water loss. In contrast, northern populations showed a stronger plastic response that limited the negative effects of reduced water availability. This study highlights the possibility that the plant response to environmental constraints (specifically water availability) may follow a geographical pattern.

  • 65.
    Abellan-Flos, Marta
    et al.
    Univ Namur, Belgium;PSL Univ, France.
    Timmer, Brian J. J.
    KTH Royal Instute of Technology, Sweden.
    Altun, Samuel
    Attana AB, Sweden.
    Aastrup, Teodor
    Attana AB, Sweden.
    Vincent, Stephane P.
    Univ Namur, Belgium.
    Ramström, Olof
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences. KTH Royal Instute of Technology, Sweden;Univ Massachusetts, USA.
    QCM sensing of multivalent interactions between lectins and well-defined glycosylated nanoplatforms2019In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 139, article id 111328Article in journal (Refereed)
    Abstract [en]

    Quartz crystal microbalance (QCM) methodology has been adopted to unravel important factors contributing to the "cluster glycoside effect" observed in carbohydrate-lectin interactions. Well-defined, glycosylated nanostructures of precise sizes, geometries and functionalization patterns were designed and synthesized, and applied to analysis of the interaction kinetics and thermodynamics with immobilized lectins. The nanostructures were based on Borromean rings, dodecaamine cages, and fullerenes, each of which carrying a defined number of carbohydrate ligands at precise locations. The synthesis of the Borromeates and dodecaamine cages was easily adjustable due to the modular assembly of the structures, resulting in variations in presentation mode. The binding properties of the glycosylated nanoplatforms were evaluated using flow-through QCM technology, as well as hemagglutination inhibition assays, and compared with dodecaglycosylated fullerenes and a monovalent reference. With the QCM setup, the association and dissociation rate constants and the associated equilibrium constants of the interactions could be estimated, and the results used to delineate the multivalency effects of the lectin-nanostructure interactions.

  • 66.
    Abeysinghe, Kasun S.
    et al.
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Yang, Xiao-Dong
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Goodale, Eben
    Guangxi Univ, Coll Forestry, Nanning, Guangxi, Peoples R China..
    Anderson, Christopher W. N.
    Massey Univ, Inst Agr & Environm, Soil & Earth Sci, Palmerston North, New Zealand..
    Bishop, Kevin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Cao, Axiang
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China.;Guizhou Normal Univ, Sch Chem & Mat Sci, Guiyang, Peoples R China..
    Feng, Xinbin
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Liu, Shengjie
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China.;Univ Chinese Acad Sci, Beijing, Peoples R China..
    Mammides, Christos
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Meng, Bo
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Quan, Rui-Chang
    Chinese Acad Sci, Xishuangbanna Trop Bot Garden, Key Lab Trop Forest Ecol, Mengla, Yunnan, Peoples R China..
    Sun, Jing
    Nanjing Agr Univ, Coll Resources & Environm Sci, Nanjing, Jiangsu, Peoples R China..
    Qiu, Guangle
    Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang, Peoples R China..
    Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil2017In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 36, no 5, p. 1202-1210Article in journal (Refereed)
    Abstract [en]

    Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia.

  • 67. Abi-Rached, Laurent
    et al.
    Jobin, Matthew J.
    Kulkarni, Subhash
    McWhinnie, Alasdair
    Dalva, Klara
    Gragert, Loren
    Babrzadeh, Farbod
    Stanford University, United States .
    Gharizadeh, Baback
    Luo, Ma
    Plummer, Francis A.
    Kimani, Joshua
    Carrington, Mary
    Middleton, Derek
    Rajalingam, Raja
    Beksac, Meral
    Marsh, Steven G. E.
    Maiers, Martin
    Guethlein, Lisbeth A.
    Tavoularis, Sofia
    Little, Ann-Margaret
    Green, Richard E.
    Norman, Paul J.
    Parham, Peter
    The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 334, no 6052, p. 89-94Article in journal (Refereed)
    Abstract [en]

    Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic human leukocyte antigen (HLA) class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.

  • 68. Abiven, Samuel
    et al.
    Hund, Andreas
    Martinsen, Vegard
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Norwegian University of Life Sciences (NMBU), Norway; Norwegian Geotechnical Institute (NGI), Norway .
    Biochar amendment increases maize root surface areas and branching: a shovelomics study in Zambia2015In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 395, no 1-2, p. 45-55Article in journal (Refereed)
    Abstract [en]

    Positive crop yield effects from biochar are likely explained by chemical, physical and/or biological factors. However, studies describing plant allometric changes are scarcer, but may be crucial to understand the biochar effect. The main aim of the present study is to investigate the effect of biochar on root architecture under field conditions in a tropical setting. The presented work describes a shovelomics (i.e., description of root traits in the field) study on the effect of biochar on maize root architecture. Four field experiments we carried out at two different locations in Zambia, exhibiting non-fertile to relatively fertile soils. Roots of maize crop (Zea mays L.) were sampled from treatments with fertilizer (control) and with a combination of fertilizer and 4 t.ha(-1) maize biochar application incorporated in the soil. For the four sites, the average grain yield increase upon biochar addition was 45 +/- 14 % relative to the fertilized control (from 2.1-6.0 to 3.1-9.1 ton ha(-1)). The root biomass was approximately twice as large for biochar-amended plots. More extensive root systems (especially characterized by a larger root opening angle (+14 +/- 11 %) and wider root systems (+20 +/- 15 %)) were observed at all biochar-amended sites. Root systems exhibited significantly higher specific surface areas (+54 +/- 14 %), branching and fine roots: +70 +/- 56 %) in the presence of biochar. Biochar amendment resulted in more developed root systems and larger yields. The more extensive root systems may have contributed to the observed yield increases, e.g., by improving immobile nutrients uptake in soils that are unfertile or in areas with prolonged dry spells.

  • 69.
    Aboye, Teshome L.
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    Strömstedt, Adam A.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    Gunasekera, Sunithi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    Bruhn, Jan G.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    El-Seedi, Hesham
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    Rosengren, K. Johan
    Göransson, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Division of Pharmacognosy.
    A Cactus-Derived Toxin-Like Cystine Knot Peptide with Selective Antimicrobial Activity2015In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 16, no 7, p. 1068-1077Article in journal (Refereed)
    Abstract [en]

    Naturally occurring cystine knot peptides show a wide range of biological activity, and as they have inherent stability they represent potential scaffolds for peptide-based drug design and biomolecular engineering. Here we report the discovery, sequencing, chemical synthesis, three-dimensional solution structure determination and bioactivity of the first cystine knot peptide from Cactaceae (cactus) family: Ep-AMP1 from Echinopsis pachanoi. The structure of Ep-AMP1 (35 amino acids) conforms to that of the inhibitor cystine knot (or knottin) family but represents a novel diverse sequence; its activity was more than 500 times higher against bacterial than against eukaryotic cells. Rapid bactericidal action and liposome leakage implicate membrane permeabilisation as the mechanism of action. Sequence homology places Ec-AMP1 in the plant C6-type of antimicrobial peptides, but the three dimensional structure is highly similar to that of a spider neurotoxin.

  • 70. Abraham, Edit
    et al.
    Miskolczi, Pal
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ayaydin, Ferhan
    Yu, Ping
    Kotogany, Edit
    Bako, Laszlo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oetvoes, Krisztina
    Horvath, Gabor V.
    Dudits, Denes
    Immunodetection of retinoblastoma-related protein and its phosphorylated form in interphase and mitotic alfalfa cells2011In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 62, no 6, p. 2155-2168Article in journal (Refereed)
    Abstract [en]

    Plant retinoblastoma-related (RBR) proteins are primarily considered as key regulators of G(1)/S phase transition, with functional roles in a variety of cellular events during plant growth and organ development. Polyclonal antibody against the C-terminal region of the Arabidopsis RBR1 protein also specifically recognizes the alfalfa 115 kDa MsRBR protein, as shown by the antigen competition assay. The MsRBR protein was detected in all cell cycle phases, with a moderate increase in samples representing G(2)/M cells. Antibody against the human phospho-pRb peptide (Ser807/811) cross-reacted with the same 115 kDa MsRBR protein and with the in vitro phosphorylated MsRBR protein C-terminal fragment. Phospho-MsRBR protein was low in G(1) cells. Its amount increased upon entry into the S phase and remained high during the G(2)/M phases. Roscovitine treatment abolished the activity of alfalfa MsCDKA1;1 and MsCDKB2;1, and the phospho-MsRBR protein level was significantly decreased in the treated cells. Colchicine block increased the detected levels of both forms of MsRBR protein. Reduced levels of the MsRBR protein in cells at stationary phase or grown in hormone-free medium can be a sign of the division-dependent presence of plant RBR proteins. Immunolocalization of the phospho-MsRBR protein indicated spots of variable number and size in the labelled interphase nuclei and high signal intensity of nuclear granules in prophase. Structures similar to phospho-MsRBR proteins cannot be recognized in later mitotic phases. Based on the presented western blot and immunolocalization data, the possible involvement of RBR proteins in G(2)/M phase regulation in plant cells is discussed.

  • 71. Abrahamczyk, S.
    et al.
    Kessler, M.
    Hanley, D.
    Karger, D. N.
    Mueller, M. P. J.
    Knauer, A. C.
    Keller, F.
    Schwerdtfeger, M.
    Humphreys, Aelys M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Imperial College London, UK.
    Pollinator adaptation and the evolution of floral nectar sugar composition2017In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 30, no 1, p. 112-127Article in journal (Refereed)
    Abstract [en]

    A long-standing debate concerns whether nectar sugar composition evolves as an adaptation to pollinator dietary requirements or whether it is 'phylogenetically constrained'. Here, we use a modelling approach to evaluate the hypothesis that nectar sucrose proportion (NSP) is an adaptation to pollinators. We analyse similar to 2100 species of asterids, spanning several plant families and pollinator groups (PGs), and show that the hypothesis of adaptation cannot be rejected: NSP evolves towards two optimal values, high NSP for specialist-pollinated and low NSP for generalist-pollinated plants. However, the inferred adaptive process is weak, suggesting that adaptation to PG only provides a partial explanation for how nectar evolves. Additional factors are therefore needed to fully explain nectar evolution, and we suggest that future studies might incorporate floral shape and size and the abiotic environment into the analytical framework. Further, we show that NSP and PG evolution are correlated - in a manner dictated by pollinator behaviour. This contrasts with the view that a plant necessarily has to adapt its nectar composition to ensure pollination but rather suggests that pollinators adapt their foraging behaviour or dietary requirements to the nectar sugar composition presented by the plants. Finally, we document unexpectedly sucrose-poor nectar in some specialized nectarivorous bird-pollinated plants from the Old World, which might represent an overlooked form of pollinator deception. Thus, our broad study provides several new insights into how nectar evolves and we conclude by discussing why maintaining the conceptual dichotomy between adaptation and constraint might be unhelpful for advancing this field.

  • 72. Abrahamson, Alexandra
    et al.
    Andersson, Carin
    Jönsson, Maria E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Environmental toxicology.
    Fogelberg, Oscar
    Orberg, Jan
    Brunstrom, Bjorn
    Brandt, Ingvar
    Gill EROD in monitoring of CYP1A inducers in fish - A study in rainbow trout (Oncorhynchus mykiss) caged in Stockholm and Uppsala waters2007In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 85, no 1, p. 1-8Article in journal (Refereed)
  • 73.
    Abrahamson, Alexandra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Andersson, Carin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Jönsson, Maria E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Fogelberg, Oscar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Örberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Brunström, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Brandt, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Gill EROD in monitoring of CYP1A inducers in fish: A study in rainbow trout (Oncorhynchus mykiss) caged in Stockholm and Uppsala waters2007In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 85, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    The gill filament 7-ethoxyresorufin O-deethylase (EROD) assay was evaluated as a monitoring tool for waterborne cytochrome P4501 A (CYP1A) inducers using rainbow trout (Oncorhynchus mykiss) caged in urban area waters in Sweden. To compare the CYP1A induction response in different tissues, EROD activity was also analyzed in liver and kidney microsomes. Immunohistochemistry was used to localize CYP1A protein in gill and kidney. In two separate experiments fish were caged at sites with fairly high expected polyaromatic hydrocarbon (PAH) contamination. In the first experiment, gill EROD activities were analyzed in fish exposed for 1-21 days in a river running through Uppsala. The reference site was upstream of Uppsala. In the second, gill, liver and kidney EROD activities were analyzed in fish exposed for 1-5 days in fresh or brackish waters of Stockholm and in a reference lake 60 km north of Stockholm. Fish exposed for 5 days followed by 2 days of recovery in tap water in the laboratory were also examined. The gill consistently showed a higher EROD induction compared with the liver and the kidney. After I day of caging, gill EROD activity was markedly induced (6-17-fold) at all sites examined. Induction in gill was pronounced (5-7-fold) also in fish caged at the reference sites. In the 21-day exposure study gill EROD activity remained highly induced throughout the experiment (26-fold at most) and the induced CYP1A protein was exclusively confined to the gill secondary lamellae. In the 5-day exposure experiment, EROD activity peaked after I day and then declined in both gill and liver, while CYP1A immunostaining in the gill remained intense over the 5-day period. In the kidney, CYP1A staining was weak or absent. We conclude that gill EROD activity is a more sensitive biomarker of exposure to waterborne CYP1A inducers than EROD activity in liver and kidney.

  • 74.
    Abrahamson, Alexandra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Brandt, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Brunström, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Physiology and Developmental Biology, Environmental Toxicology.
    Sundt, Rolf
    Jørgensen, Even
    Monitoring contaminants from oil production at sea by measuring gill EROD activity in Atlantic cod (Gadus morhua)2008In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 153, no 1, p. 169-175Article in journal (Refereed)
    Abstract [en]

    An ex vivo gill EROD assay was applied in Atlantic cod (Gadus morhua) as a biomarker for waterborne CYP1A-inducing compounds derived from oil production at sea. Exposure to nominal concentrations of 1 ppm or 10 ppm North Sea crude oil in a static water system for 24 h caused a concentration-dependent gill EROD induction. Further, exposure of cod for 14 days to environmentally relevant concentrations of produced water (PW, diluted 1:200 or 1:1000) from a platform in the North Sea using a flow-through system resulted in a concentration-dependent induction of gill EROD. Crude oil (0.2 ppm) from the same oil field also proved to induce EROD. Finally, gill EROD activity in cod caged for 6 weeks at 500-10 000 m from two platforms outside Norway was measured. The activities in these fish were very low and did not differ from those in fish caged at reference sites.

  • 75.
    Abrahamsson, S.
    et al.
    SLU, Umeå, Sweden .
    Ahlinder, J.
    FOI, Umeå, Sweden .
    Waldmann, Patrik
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, The Institute of Technology.
    García-Gil, M. R.
    SLU, Umeå, Sweden .
    Maternal heterozygosity and progeny fitness association in an inbred Scots pine population2013In: Genetica, ISSN 0016-6707, E-ISSN 1573-6857, Vol. 141, no 1-3, p. 41-50Article in journal (Refereed)
    Abstract [en]

    Associations between heterozygosity and fitness traits have typically been investigated in populations characterized by low levels of inbreeding. We investigated the associations between standardized multilocus heterozygosity (stMLH) in mother trees (obtained from12 nuclear microsatellite markers) and five fitness traits measured in progenies from an inbred Scots pine population. The traits studied were proportion of sound seed, mean seed weight, germination rate, mean family height of one-year old seedlings under greenhouse conditions (GH) and mean family height of three-year old seedlings under field conditions (FH). The relatively high average inbreeding coefficient (F) in the population under study corresponds to a mixture of trees with different levels of co-ancestry, potentially resulting from a recent bottleneck. We used both frequentist and Bayesian methods of polynomial regression to investigate the presence of linear and non-linear relations between stMLH and each of the fitness traits. No significant associations were found for any of the traits except for GH, which displayed negative linear effect with stMLH. Negative HFC for GH could potentially be explained by the effect of heterosis caused by mating of two inbred mother trees (Lippman and Zamir 2006), or outbreeding depression at the most heterozygote trees and its negative impact on the fitness of the progeny, while their simultaneous action is also possible (Lynch. 1991). However,since this effect wasn’t detected for FH, we cannot either rule out that the greenhouse conditions introduce artificial effects that disappear under more realistic field conditions.

  • 76. Abrahamsson, T. R.
    et al.
    Jakobsson, H. E.
    Andersson, Anders F.
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Björkstén, B.
    Engstrand, Lars
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Jenmalm, M. C.
    Low gut microbiota diversity in early infancy precedes asthma at school age2014In: Clinical and Experimental Allergy, ISSN 0954-7894, E-ISSN 1365-2222, Vol. 44, no 6, p. 842-850Article in journal (Refereed)
    Abstract [en]

    Background Low total diversity of the gut microbiota during the first year of life is associated with allergic diseases in infancy, but little is known how early microbial diversity is related to allergic disease later in school age. Objective To assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to the prevalence of different allergic diseases in school age, such as asthma, allergic rhinoconjunctivitis (ARC) and eczema. Methods The microbial diversity and composition was analysed with barcoded 16S rDNA 454 pyrosequencing in stool samples at 1week, 1month and 12months of age in 47 infants which were subsequently assessed for allergic disease and skin prick test reactivity at 7years of age (ClinicalTrials.gov ID NCT01285830). Results Children developing asthma (n=8) had a lower diversity of the total microbiota than non-asthmatic children at 1week (P=0.04) and 1month (P=0.003) of age, whereas allergic rhinoconjunctivitis (n=13), eczema (n=12) and positive skin prick reactivity (n=14) at 7years of age did not associate with the gut microbiota diversity. Neither was asthma associated with the microbiota composition later in infancy (at 12months). Children having IgE-associated eczema in infancy and subsequently developing asthma had lower microbial diversity than those that did not. There were no significant differences, however, in relative abundance of bacterial phyla and genera between children with or without allergic disease. Conclusion and Clinical Relevance Low total diversity of the gut microbiota during the first month of life was associated with asthma but not ARC in children at 7years of age. Measures affecting microbial colonization of the infant during the first month of life may impact asthma development in childhood.

  • 77. Abrahamsson, Thomas R.
    et al.
    Jakobsson, Hedvig E.
    Andersson, Anders F.
    KTH, School of Biotechnology (BIO), Gene Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Björksten, Bengt
    Engstrand, Lars
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Jenmalm, Maria C.
    Gut microbiota diversity and atopic disease: Does breast-feeding play a role? Reply2013In: Journal of Allergy and Clinical Immunology, ISSN 0091-6749, E-ISSN 1097-6825, Vol. 131, no 1, p. 248-249Article in journal (Other academic)
  • 78.
    Abramenkovs, Andris
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Stenerlöw, Bo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science.
    Measurement of DNA-Dependent Protein Kinase Phosphorylation Using Flow Cytometry Provides a Reliable Estimate of DNA Repair Capacity2017In: Radiation Research, ISSN 0033-7587, E-ISSN 1938-5404, Vol. 188, no 6, p. 597-604Article in journal (Refereed)
    Abstract [en]

    Uncontrolled generation of DNA double-strand breaks (DSBs) in cells is regarded as a highly toxic event that threatens cell survival. Radiation-induced DNA DSBs are commonly measured by pulsed-field gel electrophoresis, microscopic evaluation of accumulating DNA damage response proteins (e.g., 53BP1 or gamma-H2AX) or flow cytometric analysis of gamma-H2AX. The advantage of flow cytometric analysis is that DSB formation and repair can be studied in relationship to cell cycle phase or expression of other proteins. However, gamma-H2AX is not able to monitor repair kinetics within the first 60 min postirradiation, a period when most DSBs undergo repair. A key protein in non-homologous end joining repair is the catalytic subunit of DNA-dependent protein kinase. Among several phosphorylation sites of DNA-dependent protein kinase, the threonine at position 2609 (T2609), which is phosphorylated by ataxia telangiectasia mutated (ATM) or DNA-dependent protein kinase catalytic subunit itself, activates the end processing of DSB. Using flow cytometry, we show here that phosphorylation at T2609 is faster in response to DSBs than gamma-H2AX. Furthermore, flow cytometric analysis of T2609 resulted in a better representation of fast repair kinetics than analysis of gamma-H2AX. In cells with reduced ligase IV activity, and wild-type cells where DNA-dependent protein kinase activity was inhibited, the reduced DSB repair capacity was observed by T2609 evaluation using flow cytometry. In conclusion, flow cytometric evaluation of DNA-dependent protein kinase T2609 can be used as a marker for early DSB repair and gives a better representation of early repair events than analysis of gamma-H2AX.

  • 79.
    Abramson, Jeff
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Structural studies on the integral membrane protein, ubiquinol oxidase from Escherichia coli2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Heme-copper oxidases are redox-driven proton pumps that couple the reduction of molecular oxygen to water with the vectorial translocation of protons across the membrane. The proton gradient generated by heme-copper oxidases and the other members of the aerobic respiratory chain is ultimately used to drive the synthesis of ATP. There are two main branches of the heme-copper oxidases that are characterized by the electron donating substrate; the cytochrome c oxidases, which use cytochrome c as the electron donor, and the ubiquinol oxidases, which use a lipid-soluble molecule, ubiquinol, as their electron donor. These enzymes share important structural and functional features.

    This thesis presents the procedures that have led to the first crystal structure of a ubiquinol oxidase, cytochrome bo, oxidase from Escherichia coli, at a resolution of 3.5 Å. The overall structure of the enzyme is similar to those of cytochrome c oxidases; however the membrane spanning region of subunit I contains a cluster of polar residues exposed to the interior of the lipid bilayer. No such structural feature is present in cytochrome c oxidases. Mutagenesis studies on residues in this region strongly suggest that this area forms a ubiquinone binding site. A comparison of this region with known ubiquinone binding sites shows remarkable similarities. In light of these findings specific roles for these polar residues is proposed in electron and proton transfer in ubiquinol oxidase.

    A fusion protein of cytochrome bo3-Protein Z was generated in an attempt to increase the hydrophilic surface of the protein, thus extending protein-protein contacts within the crystal lattice structure. Such an approach can be used to facilitate crystallization.

  • 80.
    Abreu, Ilka Nacif
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ahnlund, Maria
    Moritz, Thomas
    Albrectsen, Benedicte R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    UHPLC-ESI/TOFMS Determination of Salicylate-like Phenolic Gycosides in Populus tremula Leaves2011In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 37, no 8, p. 857-70Article in journal (Refereed)
    Abstract [en]

    Associations of salicylate-like phenolic glycosides (PGs) with biological activity have been reported in Salix and Populus trees, but only for a few compounds, and in relation to a limited number of herbivores. By considering the full diversity of PGs, we may improve our ability to recognize genotypes or chemotype groups and enhance our understanding of their ecological function. Here, we present a fast and efficient general method for salicylate determination in leaves of Eurasian aspen that uses ultra-high performance liquid chromatography-electrospray ionization/time-of-flight mass spectrometry (UHPLC-ESI/TOFMS). The time required for the liquid chromatography separations was 13.5 min per sample, compared to around 60 min per sample for most HPLC protocols. In leaf samples from identical P. tremula genotypes with diverse propagation and treatment histories, we identified nine PGs. We found the compound-specific mass chromatograms to be more informative than the UV-visible chromatograms for compound identification and when quantitating samples with large variability in PG content. Signature compounds previously reported for P. tremoloides (tremulacin, tremuloidin, salicin, and salicortin) always were present, and five PGs (2'-O-cinnamoyl-salicortin, 2'-O-acetyl-salicortin, 2'-O-acetyl-salicin, acetyl-tremulacin, and salicyloyl-salicin) were detected for the first time in P. tremula. By using information about the formic acid adduct that appeared for PGs in the LTQ-Orbitrap MS environment, novel compounds like acetyl-tremulacin could be tentatively identified without the use of standards. The novel PGs were consistently either present in genotypes regardless of propagation and damage treatment or were not detectable. In some genotypes, concentrations of 2'-O-acetyl-salicortin and 2'-O-cinnamoyl-salicortin were similar to levels of biologically active PGs in other Salicaceous trees. Our study suggests that we may expect a wide variation in PG content in aspen populations which is of interest both for studies of interactions with herbivores and for mapping population structure.

  • 81.
    Abreu, Murilo S.
    et al.
    Fed Univ Santa Maria UFSM, Grad Program Pharmacol, BR-97105900 Santa Maria, RS, Brazil.
    Messias, Joao P. M.
    Univ Porto, Ctr Invest Biodiversidade & Recursos Genet, CIBIO, Campus Agr Vairao, P-4485661 Vairao, Portugal.
    Thörnqvist, Per-Ove
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Winberg, Svante
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Soares, Marta C.
    Univ Porto, Ctr Invest Biodiversidade & Recursos Genet, CIBIO, Campus Agr Vairao, P-4485661 Vairao, Portugal.
    Monoaminergic levels at the forebrain and diencephalon signal for the occurrence of mutualistic and conspecific engagement in client reef fish2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 7346Article in journal (Refereed)
    Abstract [en]

    Social interactions are commonly found among fish as in mammals and birds. While most animals interact socially with conspecifics some however are also frequently and repeatedly observed to interact with other species (i.e. mutualistic interactions). This is the case of the (so-called) fish clients that seek to be cleaned by other fish (the cleaners). Clients face an interesting challenge: they raise enough motivation to suspend their daily activities as to selectively visit and engage in interactions with cleaners. Here we aimed, for the first time, to investigate the region-specific brain monoaminergic level differences arising from individual client fish when facing a cleaner (interspecific context) compared to those introduced to another conspecific (socio-conspecific context). We show that monoaminergic activity differences occurring at two main brain regions, the diencephalon and the forebrain, are associated with fish clients' social and mutualistic activities. Our results are the first demonstration that monoaminergic mechanisms underlie client fish mutualistic engagement with cleanerfish. These pathways should function as a pre-requisite for cleaning to occur, providing to clients the cognitive and physiological tools to seek to be cleaned.

  • 82.
    Abreu-Vieira, Gustavo
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Regulation and measurement of brown adipose tissue blood flow2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Brown adipose tissue (BAT) is an organ specialized in macromolecule combustion in order to produce heat. Because of its high capacity to dissipate energy, it is currently among the best hopes for future treatments of obesity and diabetes. BAT is permeated by a vast capillary network that delivers blood rich in oxygen and nutrients to supply the high metabolic needs of the tissue. At the same time, metabolites, carbon dioxide and warm blood are drained back into systemic circulation. Blood flow is in fact a limiting factor for thermogenesis. Therefore, understanding BAT blood flow regulation is a crucial step for describing the tissue function. This thesis aims to summarize anatomical descriptions, to discuss the methodological evolution of the field, and to synthetize what we have learned about mechanistic regulation of BAT blood flow during the last half century. Manuscript I introduces a new method (high-resolution laser-doppler imaging) for the measurement of BAT blood flow, and gives mechanistic insights about its physiological regulation. Manuscript II focuses on the influence of bombesin receptor subtype-3 on the neurological control of body temperature and thermogenesis.

  • 83.
    Abreu-Vieira, Gustavo
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Bengtsson, Tore
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Petrovic, Natasa
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Nedergaard, Jan
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    On adequate procedures for glucose tolerance tests in obese animals: Measurement of glucose tolerance in obesityManuscript (preprint) (Other academic)
    Abstract [en]

    Routine procedures for glucose tolerance test in rodents utilize an amount of injected glucose that is proportional to total body weight (normally 2 mg per g body weight). Obese mice consist of much more chemically inert lipid than lean mice but have only marginal increases in lean body mass (the only compartment where glucose is distributed). Present procedures thus inevitably lead to a diagnosis of impaired glucose tolerance and enhanced insulin levels in obesity. Routine procedures should use fixed glucose amounts per lean body mass (or per mouse).

  • 84.
    Abreu-Vieira, Gustavo
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Fischer, Alexander W.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. University of Hamburg, Germany.
    Mattsson, Charlotte
    de Jong, Jasper M. A.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Shabalina, Irina G.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Ryden, Mikael
    Laurencikiene, Jurga
    Arner, Peter
    Cannon, Barbara
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Nedergaard, Jan
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Petrovic, Natasa
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Cidea improves the metabolic profile through expansion of adipose tissue2015In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 6, article id 7433Article in journal (Refereed)
    Abstract [en]

    In humans, Cidea (cell death-inducing DNA fragmentation factor alpha-like effector A) is highly but variably expressed in white fat, and expression correlates with metabolic health. Here we generate transgenic mice expressing human Cidea in adipose tissues (aP2-hCidea mice) and show that Cidea is mechanistically associated with a robust increase in adipose tissue expandability. Under humanized conditions (thermoneutrality, mature age and prolonged exposure to high-fat diet), aP2-hCidea mice develop a much more pronounced obesity than their wild-type littermates. Remarkably, the malfunctioning of visceral fat normally caused by massive obesity is fully overcome-perilipin 1 and Akt expression are preserved, tissue degradation is prevented, macrophage accumulation is decreased and adiponectin expression remains high. Importantly, the aP2-hCidea mice display enhanced insulin sensitivity. Our data establish a functional role for Cidea and suggest that, in humans, the association between Cidea levels in white fat and metabolic health is not only correlative but also causative.

  • 85.
    Abreu-Vieira, Gustavo
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Hagberg, Carolina E.
    Spalding, Kirsty L.
    Cannon, Barbara
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Nedergaard, Jan
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Adrenergically-stimulated blood flow in brown adipose tissue is not dependent on thermogenesis: Regulation of brown adipose tissue blood flow2015In: American Journal of Physiology. Endocrinology and Metabolism, ISSN 0193-1849, E-ISSN 1522-1555, Vol. 308, no 9, p. E822-E829Article in journal (Refereed)
    Abstract [en]

    Brown adipose tissue (BAT) thermogenesis relies on blood flow to be supplied with nutrients and oxygen, and for the distribution of the generated heat to the rest of the body. It is therefore fundamental to understand the mechanisms by which blood flow is regulated and its relation to thermogenesis. Here we present high-resolution laser-Doppler imaging (HR-LDR) as a novel method for noninvasive, in vivo measurement of BAT blood flow in mice. Using HR-LDR, we found that norepinephrine stimulation increases BAT blood flow in a dose-dependent manner, and that this response is profoundly modulated by environmental temperature acclimation. Surprisingly, we found that mice lacking uncoupling protein 1 (UCP1) have fully preserved BAT blood flow response to norepinephrine, despite failing to perform thermogenesis. BAT blood flow was not directly correlated to systemic glycaemia, but glucose injections could transiently increase tissue perfusion. Inguinal white adipose tissue, also known as a brite/beige adipose tissue, was also sensitive to cold acclimation and similarly increased blood flow in response to norepinephrine. In conclusion, using a novel non-invasive method to detect BAT perfusion, we demonstrate that adrenergically-stimulated BAT blood flow is qualitatively and quantitatively fully independent of thermogenesis, and is therefore not a reliable parameter for the estimation of BAT activation and heat generation.

  • 86.
    Abreu-Vieira, Gustavo
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. National Institute of Diabetes and Digestive and Kidney Diseases, NIH, USA.
    Xiao, Cuiying
    Gavrilova, Oksana
    Reitman, Marc L.
    Integration of body temperature into the analysis of energy expenditure in the mouse2015In: Molecular Metabolism, ISSN 2212-8778, Vol. 4, no 6, p. 461-470Article in journal (Refereed)
    Abstract [en]

    Objectives: We quantified the effect of environmental temperature on mouse energy homeostasis and body temperature.Methods: The effect of environmental temperature (4e33 C) on body temperature, energy expenditure, physical activity, and food intake invarious mice (chow diet, high-fat diet, Brs3-/y, lipodystrophic) was measured using continuous monitoring.Results: Body temperature depended most on circadian phase and physical activity, but also on environmental temperature. The amounts ofenergy expenditure due to basal metabolic rate (calculated via a novel method), thermic effect of food, physical activity, and cold-inducedthermogenesis were determined as a function of environmental temperature. The measured resting defended body temperature matchedthat calculated from the energy expenditure using Fourier’s law of heat conduction. Mice defended a higher body temperature during physicalactivity. The cost of the warmer body temperature during the active phase is 4e16% of total daily energy expenditure. Parameters measured indiet-induced obese and Brs3-/y mice were similar to controls. The high post-mortem heat conductance demonstrates that most insulation in miceis via physiological mechanisms.Conclusions: At 22 C, cold-induced thermogenesis isw120% of basal metabolic rate. The higher body temperature during physical activity isdue to a higher set point, not simply increased heat generation during exercise. Most insulation in mice is via physiological mechanisms, with littlefrom fur or fat. Our analysis suggests that the definition of the upper limit of the thermoneutral zone should be re-considered. Measuring bodytemperature informs interpretation of energy expenditure data and improves the predictiveness and utility of the mouse to model human energyhomeostasis.

  • 87.
    Abrikossov, Alexei
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre.
    Computer simulations: Orientation of Lysozyme in vacuum under the influence of an electric field2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The possibility to orient a protein in space using an external electrical field was studied bymeans of molecular dynamics simulations. To model the possible conditions of an electrospray ionization (ESI) the protein Lysozyme in vacuum was considered under the influence ofdifferent field strengths. The simulations showed three distinct patterns: (1) the protein wasdenaturated when exposed to too strong electrical fields, above 1.5 V/nm; (2) the proteinoriented without being denaturated at field strengths between 0.5 V/nm and 1.5 V/nm (3) theprotein did not orient and did not denaturate if the strength of the field became to low, below0.5 V/nm. Our simulations show that the orientation of the protein in the fields correspondingto the second pattern takes place within time intervals from about 100 ps at 1.5 V/nm to about1 ns at 0.5 V/nm. We therefore predict, that there exists a window of field strengths, which issuitable for orientation of proteins in experimental studies without affecting their structure.The orientation of proteins potentially increases the amount of information that can beobtained from experiments such as single particle imaging. This study will therefore bebeneficial for the development of such modern techniques.

  • 88.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Investigation of nanoparticle-cell interactions for development of next generation of biocompatible MRI contrast agents2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Progress in synthesis technologies and advances in fundamental understanding of materials with low dimensionality has led to the birth of a new scientific field, nanoscience, and to strong expectations of multiple applications of nanomaterials. The physical properties of small particles are unique, bridging the gap between atoms and molecules, on one side, and bulk materials on the other side. The work presented in this thesis investigates the potential of using magnetic nanoparticles as the next generation of contrast agents for biomedical imaging. The focus is on gadolinium-based nanoparticles and cellular activity including the uptake, morphology and production of reactive oxygen species.

    Gd ion complexes, like Gd chelates, are used today in the clinic, world-wide. However, there is a need for novel agents, with improved contrast capabilities and increased biocompatibility. One avenue in their design is based on crystalline nanoparticles. It allows to reduce the total number of Gd ions needed for an examination. This can be done by nanotechnology, which allows one to improve and fine tune the physico- chemical properties on the nanomaterial in use, and to increase the number of Gd atoms at a specific site that interact with protons and thereby locally increase the signal. In the present work, synthesis, purification and surface modification of crystalline Gd2O3-based nanoparticles have been performed. The nanoparticles are selected on the basis of their physical properties, that is they show enhanced magnetic properties and therefore may be of high potential interest for applications as contrast agents.

    The main synthesis method of Gd2O3 nanoparticles in this work was the modified “polyol” route, followed by purification of as-synthesized DEG-Gd2O3 nanoparticles suspensions. In most cases the purification step involved dialysis of the nanoparticle samples. In this thesis, organosilane were chosen as an exchange agent for further functionalization. Moreover, several paths have been explored for modification of the nanoparticles, including Tb3+ doping and capping with sorbitol.

    Biocompatibility of the newly designed nanoparticles is a prerequisite for their use in medical applications. Its evaluation is a complex process involving a wide range of biological phenomena. A promising path adopted in this work is to study of nanoparticle interactions with isolated blood cells. In this way one could screen nanomaterial prior to animal studies.

    The primary cell type considered in the thesis are polymorphonuclear neutrophils (PMN) which represent a type of the cells of human blood belonging to the granulocyte family of leukocytes. PMNs act as the first defense of the immune system against invading pathogens, which makes them valuable for studies of biocompatibility of newly synthesized nanoparticles. In addition, an immortalized murine alveolar macrophage cell line (MH-S), THP-1 cell line, and Ba/F3 murine bone marrow-derived cell line were considered to investigate the optimization of the cell uptake and to examine the potential of new intracellular contrast agent for magnetic resonance imaging.

    In paper I, the nanoparticles were investigated in a cellular system, as potential probes for visualization and targeting intended for bioimaging applications. The production of reactive oxygen species (ROS) by means of luminol-dependent chemiluminescence from human neutrophils was studied in presence of Gd2O3 nanoparticles. In paper II, a new design of functionalized ultra-small rare earth-based nanoparticles was reported. The synthesis was done using polyol method followed by PEGylation, and dialysis. Supersmall gadolinium oxide (DEG-Gd2O3) nanoparticles, in the range of 3-5 nm were obtained and carefully characterized. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. In paper III, cell labeling with Gd2O3 nanoparticles in hematopoietic cells was monitored by magnetic resonance imaging (MRI). In paper IV, ultra-small gadolinium oxide nanoparticles doped with terbium ions were synthesized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. Paramagnetic behavior was studied. MRI contrast enhancement was received, and the luminescent/ fluorescent property of the particles was attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. Fluorescent labeling of living cells was obtained. In manuscript V, neutrophil granulocytes were investigated with rapid cell signaling communicative processes in time frame of minutes, and their response to cerium-oxide based nanoparticles were monitored using capacitive sensors based on Lab-on-a-chip technology. This showed the potential of label free method used to measure oxidative stress of neutrophil granulocytes. In manuscript VI, investigations of cell-(DEGGd2O3) nanoparticle interactions were carried out. Plain (DEG-Gd2O3) nanoparticles, (DEG-Gd2O3) nanoparticles in presence of sorbitol and (DEG-Gd2O3) nanoparticles capped with sorbitol were studied. Relaxation studies and measurements of the reactive oxygen species production by neutrophils were based on chemiluminescence. Cell morphology was evaluated as a parameter of the nanoparticle induced inflammatory response by means of the fluorescence microscopy.

    The thesis demonstrates high potential of novel Gd2O3-based nanoparticles for development of the next generation contrast agents, that is to find biocompatible compounds with high relaxivity that can be detected at lower doses, and in the future enable targeting to provide great local contrast.

  • 89.
    Abrikossova, Natalia
    Linköping University, The Department of Physics, Chemistry and Biology.
    In-vitro studier av inflammatorisk svar från helblod och neutrofila granulocyter vid aktivering med nanopartiklar2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [sv]

    Syftet med detta arbete var att studera inflammatoriska effekter i mänskligt helblod och neutrofila granulocyter exponerade och stimulerade av nanopartiklar av gadoliniumoxid. Projektet utreder den toxiska potentialen hos nanopartiklar med olika kemiska och morfologiska egenskaper.

    I experimenten undersöktes cellresponsen hos blodceller exponerade med ofunktionaliserade och funktionaliserade nanopartiklarna. Effekterna av funktionaliserade och ofunktionaliserade nanopartiklarna på aggregation och syreradikalproduktion i helblod och hos neutrofila granulocyter studerades med hjälp av lumi-aggregometri.

    Studier har visat att varken ofunktionaliserade eller funktionaliserade nanopartiklarna ger aggregation i blodet. Syreradikalproduktionen ökar däremot. Resultaten av studier i helblod visar att stimulering med spädnings serier av funktionaliserade nanopartiklar ger mindre frisättning av syreradikaler än spädnings serier med ofunktionaliserade nanopartiklar. Detta bekräftas med studier av morfologiska skillnader i neutrofila granulocyter som var stimulerade med olika typer av nanopartiklar. Detta gjordes med hjälp av fluorescensmikroskopi. Resultaten från studierna tyder på att funktionaliserade nanopartiklar är mindre inflammatoriska än ofunktionaliserade nanopartiklar.

  • 90.
    Abromaitis, V.
    et al.
    Kaunas Univ Technol, Lithuania ; Wetsus, European Ctr Excellence Sustainable Water Technol, Netherlands.
    Racys, V.
    Kaunas Univ Technol, Lithuania.
    van der Marel, P.
    WLN, Netherlands.
    Ni, Gaofeng
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Dopson, Mark
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Wolthuizen, A. L.
    Wageningen Univ, Netherlands.
    Meulepas, R. J. W.
    Wetsus, European Ctr Excellence Sustainable Water Technol, Netherlands.
    Effect of shear stress and carbon surface roughness on bioregeneration and performance of suspended versus attached biomass in metoprolol-loaded biological activated carbon systems2017In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 317, p. 503-511Article in journal (Refereed)
    Abstract [en]

    The bioregeneration of activated carbon (AC) in biological activated carbon (BAC) systems is limited by sorption-desorption hysteresis and transport between the adsorbent and biomass. In this study, we investigated these limitations and whether a biofilm covering the AC surface is required. Consequently, BAC reactors were operated at different shear stress and AC surface smoothness, since this may affect biofilm formation. The experiments were carried out in BAC and blank reactors treating synthetic wastewater containing the pharmaceutical metoprolol. After start-up, all reactors removed metoprolol completely; however, after 840 h the removal dropped due to saturation of the AC. In the blank reactors, the removal dropped to 0% while in the BAC reactors removal recovered to >99%, due to increased biological activity. During the initial phase, the metoprolol was adsorbed, rather than biodegraded. At the end, the AC from the BAC reactors had higher pore volume and sorption capacity than from the blank reactors, showing that the AC had been bioregenerated. At high shear (G = 25 s(-1)), the rough AC granules (R-a = 13 mu m) were covered with a 50-400 gm thick biofilm and the total protein content of the biofilm was 2.6 mg/gAC, while at lower shear (G = 8.8 s(-1)) the rough AC granules were only partly covered. The biofilm formation at lower shear (G = 8.8 s(-1)) on smooth AC granules (R-a = 1.6 mu m) was negligible. However, due to the presence of suspended biomass the reactor performance or bioregeneration were not reduced. This showed that direct contact between the AC and biomass was not essential in mixed BAC systems. The microbial analyses of the suspended biomass and the biofilm on AC surface indicated that metoprolol was mainly biodegraded in suspension. (C) 2017 Elsevier B.V. All rights reserved.

  • 91.
    Abrouk, Michael
    et al.
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Balcarkova, Barbora
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Simkova, Hana
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Kominkova, Eva
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Martis, Mihaela-Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Institute for Bioinformatics and Systems Biology, Helmholtz Center Munich, Neuherberg, Germany.
    Jakobson, Irena
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Timofejeva, Ljudmilla
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Rey, Elodie
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Vrana, Jan
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Kilian, Andrzej
    Diversity Arrays Technology Pty Ltd, Yarralumla, ACT2600, Australia.
    Järve, Kadri
    Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn 19086, Estonia.
    Dolezel, Jaroslav
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    Valarik, Miroslav
    Institute of Experimental Botany, Centre of the Region Hana for Biotechnological and Agricultural Research, Olomouc, Czech Republic.
    The in silico identification and characterization of a bread wheat/Triticum militinae introgression line: Characterization of alien introgression in wheat2017In: Plant Biotechnology Journal, ISSN 1467-7644, E-ISSN 1467-7652, Vol. 15, no 2, p. 249-256Article in journal (Refereed)
    Abstract [en]

    The capacity of the bread wheat (Triticum aestivum) genome to tolerate introgression from related genomes can be exploited for wheat improvement. A resistance to powdery mildew expressed by a derivative of the cross bread wheat cv. Tähti ⨯ T. militinae (Tm) is known to be due to the incorporation of a Tm segment into the long arm of chromosome 4A. Here, a newly developed in silico method termed RICh (rearrangement identification and characterization) has been applied to characterize the introgression. A virtual gene order, assembled using the GenomeZipper approach, was obtained for the native copy of chromosome 4A; it incorporated 570 4A DArTseq markers to produce a zipper comprising 2,132 loci. A comparison between the native and introgressed forms of the 4AL chromosome arm showed that the introgressed region is located at the distal part of the arm. The Tm segment, derived from chromosome 7G, harbors 131 homoeologs out of the 357 genes present on the corresponding region of Chinese Spring 4AL. The estimated number of Tm genes transferred along with the disease resistance gene was 169. Characterizing the introgression's position, gene content and internal gene order should facilitate not only gene isolation, but may also be informative with respect to chromatin structure and behavior studies.

  • 92.
    Abu Bakar, Siddique
    Stockholm University.
    Immunological and functional properties of a non-repeat region in Plasmodium falciparum antigen Pf155/RESA1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plasmodium falciparum malaria is one of the most prevalent of all the great insect-borne diseases causing high morbidity and mortality in humans. As conventional anti-malarial treatment is becoming increasingly inefficient, alternative approaches to combat the parasite, like vaccine development, are of high priority. Among other antigens, Pf155/RESA has been taken into consideration for inclusion in a vaccine against the asexual blood stages of P. falciparum. Repeat sequences of this antigen induce neutralizing antibodies and are potentially involved in protective immune responses. However, the genetic restriction in the immune responses to these epitopes has made it of importance to define additional regions in this antigen which may be suitable for inclusion in a vaccine. The present studies were aimed at investigating potential immunodominant B- and T-cell epitopes in the non-repeat regions of Pf155/RESA suitable for inclusion in subunit vaccine immunogens.

    In order to define immunodominant B- and T-cell epitopes, short overlapping peptides were synthesized, corresponding to three different non-repeat sequences of Pf155/RESA. Sera collected from malaria endemic countries recognized pepetides representing N-terminal sequences of the antigen. Based on high antibody reactivity in ELISA, two peptides were selected for affinity purification of antibodies from Liberian sera. The purified antibodies were shown to be efficient in parasite growth inhibition in vitro. Furthermore, the peptides had the ability to stimulate peripheral blood mononuclear cells from P. falciparum-immune donors to proliferate and to secrete IL-4 and/or IFN-g. Although the frequency of responders was high, the magnitude of the responses was generally low.

    Antibodies were raised in rabbits against synthetic peptides corresponding to different non-repeat sequences in Pf155/RESA. Although all antisera reacted strongly with the corresponding peptide, they reacted only weakly with full-length Pf155/RESA. Antibodies to some of the non-repeat sequences inhibited merozoite invasion in vitro, notably, also the invasion of parasites deficient in Pf155/RESA, indicating the presence of an antigen highly homologous to Pf155/RESA.

    Upon infection with P. falciparum, erythrocytes expose cryptic determinants in band 3, which are thought to mediate cytoadherence to endothelial cells. The N-terminal non-repeat region of Pf155/RESA contains a hexapeptide motif which is highly homologous to the cytoadherence related sequences of erythrocyte band 3. Synthetic peptides containing this hexapeptide motif inhibited the binding of P. falciparum-infected erythrocytes to melanoma cells in vitro. Antibodies raised against the largely overlapping sequences displayed highly different specificity patterns. Antibodies to the cytoadherence related motif of Pf155/RESA as well as antibodies raised against the peptides corresponding to the band 3 motif inhibited cytoadherence but not parasite growth. In contrast antibodies to sequences adjacent to the Pf155/RESA cytoadherence motif inhibited parasite growth in vitro but had no effect on cytoadherence.

    In summary, although the target antigens for the anti-parasitic activities displayed by the antibodies in these studies are unclear, sequences in non-repeat regions of Pf155/RESA may induce antibodies with capacity to inhibit parasite growth in vitro or to block the cytoadherence of P. falciparum infected erythrocytes to endothelial cells. The combination of non-repeat sequences with repeat sequences of Pf155/RESA in a subunit vaccine may provide immunogens with an improved capacity to induce parasite neutralizing antibody responses.

  • 93.
    Abuabaid, Hanan
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Mattias
    Örebro University, School of Science and Technology.
    Scherbak, Nikolai
    Örebro University, School of Science and Technology.
    Olsson, Per-Erik
    Örebro University, School of Science and Technology.
    Jass, Jana
    Örebro University, School of Science and Technology.
    Probiotic Lactobacillus rhamnosus alters inflammatory responses of bladder epithelial and macrophage-like cells in co-cultureManuscript (preprint) (Other academic)
  • 94.
    Abudaya, Mohammed
    et al.
    Natl Res Ctr, Palestine.
    Ulman, Aylin
    Univ British Columbia, Canada.
    Salah, Jehad
    Minist Agr, Palestine.
    Fernando, Daniel
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Manta Trust, UK;Blue Resources Trust, Sri Lanka.
    Wor, Catarina
    Univ British Columbia, Canada.
    di Sciara, Giuseppe Notarbartolo
    Tethys Res Inst, Italy.
    Speak of the devil ray (Mobula mobular) fishery in Gaza2018In: Reviews in Fish Biology and Fisheries, ISSN 0960-3166, E-ISSN 1573-5184, Vol. 28, no 1, p. 229-239Article in journal (Refereed)
    Abstract [en]

    Little is known about the giant devil ray (Mobula mobular), an endangered species endemic to the Mediterranean. Gaza is the only region where this species is targeted, hence, this fishery was studied to address the knowledge gap on fishery interactions, species behavior, and life-history traits. Devil rays have been frequenting this maritime area for at least the past 50 years for a short window from February to April. Landings are reported from 2005 to 2016, along with disc-width (DW) measurements for recent years. A total of 304 M. mobular (over 90% males) were landed in Gaza from 2014 to 2016, most which were mature and appeared to be mating (over 90% of males had sperm-filled claspers), providing critical insight that this area may serve as a mating ground. Yearly landings are shown here to closely match the allowed fishing distance from shore, which changes regularly, indicating that the rays are normally caught between 6 and 12 n.m. offshore. Width-weight conversion parameters are calculated for the first time for this species: a = 2.68 x 10(-6) and b = 4.39. Fresh protein drives this local fishery, as food security is a major issue. An export market for gill plates was reported intermittently, and is no longer possible due to strict trade restrictions. We highlight the lack of awareness of fishers regarding the IUCN's Red List 'Endangered' status of devil rays, and stress the urgent need for national protection of this species, particularly due to the species' very slow life-history traits and probable usage of this area as a mating ground.

  • 95. Abunge, Caroline
    et al.
    Coulthard, Sarah
    Daw, Tim M.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Connecting Marine Ecosystem Services to Human Well-being: Insights from Participatory Well-being Assessment in Kenya2013In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, no 8, p. 1010-1021Article in journal (Refereed)
    Abstract [en]

    The linkage between ecosystems and human well-being is a focus of the conceptualization of ecosystem services as promoted by the Millennium Ecosystem Assessment. However, the actual nature of connections between ecosystems and the well-being of individuals remains complex and poorly understood. We conducted a series of qualitative focus groups with five different stakeholder groups connected to a small-scale Kenyan coastal fishery to understand (1) how well-being is understood within the community, and what is important for well-being, (2) how people's well-being has been affected by changes over the recent past, and (3) people's hopes and aspirations for their future fishery. Our results show that people conceive well-being in a diversity of ways, but that these can clearly map onto the MA framework. In particular, our research unpacks the freedoms and choices element of the framework and argues for greater recognition of these aspects of well-being in fisheries management in Kenya through, for example, more participatory governance processes.

  • 96.
    Abu-Siniyeh, Ahmed
    et al.
    Univ New S Wales, Sch Med Sci, ARC Ctr Adv Mol Imaging, Sydney, NSW 2052, Australia.;Univ New S Wales, Australian Ctr NanoMed, Sydney, NSW 2052, Australia..
    Owen, Dylan M.
    Kings Coll London, Dept Phys, London WC2R 2LS, England.;Kings Coll London, Randall Div Cell & Mol Biophys, London WC2R 2LS, England..
    Benzing, Carola
    Univ New S Wales, Sch Med Sci, ARC Ctr Adv Mol Imaging, Sydney, NSW 2052, Australia.;Univ New S Wales, Australian Ctr NanoMed, Sydney, NSW 2052, Australia..
    Rinkwitz, Silke
    Becker, Thomas S.
    Univ Sydney, Brain & Mind Res Inst, Sydney Med Sch, Sydney, NSW 2006, Australia.;Univ Sydney, Dept Hlth Sci, Sydney, NSW 2006, Australia..
    Majumdar, Arindam
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Vascular Biology.
    Gaus, Katharina
    Univ New S Wales, Sch Med Sci, ARC Ctr Adv Mol Imaging, Sydney, NSW 2052, Australia.;Univ New S Wales, Australian Ctr NanoMed, Sydney, NSW 2052, Australia..
    The aPKC/Par3/Par6 Polarity Complex and Membrane Order Are Functionally Interdependent in Epithelia During Vertebrate Organogenesis2016In: Traffic: the International Journal of Intracellular Transport, ISSN 1398-9219, E-ISSN 1600-0854, Vol. 17, no 1, p. 66-79Article in journal (Refereed)
    Abstract [en]

    The differential distribution of lipids between apical and basolateral membranes is necessary for many epithelial cell functions, but how this characteristic membrane organization is integrated within the polarity network during ductal organ development is poorly understood. Here we quantified membrane order in the gut, kidney and liver ductal epithelia in zebrafish larvae at 3-11 days post fertilization (dpf) with Laurdan 2-photon microscopy. We then applied a combination of Laurdan imaging, antisense knock-down and analysis of polarity markers to understand the relationship between membrane order and apical-basal polarity. We found a reciprocal relationship between membrane order and the cell polarity network. Reducing membrane condensation by exogenously added oxysterol or depletion of cholesterol reduced apical targeting of the polarity protein, aPKC. Conversely, using morpholino knock down in zebrafish, we found that membrane order was dependent upon the Crb3 and Par3 polarity protein expression in ductal epithelia. Hence our data suggest that the biophysical property of membrane lipid packing is a regulatory element in apical basal polarity.

  • 97.
    Abuzooda, Thana
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Amini, Ahmad
    Abdel-Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Graphite-based microextraction by packed sorbent for online extraction of beta-blockers from human plasma samples2015In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 992, p. 86-90Article in journal (Refereed)
    Abstract [en]

    In the present work a new graphitic material (Carbon-XCOS) was used as a sorbent for microextraction by packed sorbent (MEPS).The beta-blockers metoprolol and acebutolol in plasma samples were extracted and detected online using Carbon-MEPS syringe and liquid chromatography and tandem mass spectrometry (LC-MS/MS). Factors affecting the MEPS performance such as conditioning, washing and elution solutions were investigated. The validation of the bioanalytical method was performed using human plasma. The standard curve ranged from 10 to 2000 nM and the lower limit of quantification (LLOQ) was set to 10 nM. The method validation showed good accuracy and precision for the quality control (QC) samples at three concentration levels (30, 800 and 1600 nM). The accuracy values of the QC samples were in the range of 86-108% (n = 18). The precision values of intra- and inter-day for QC samples ranged from 4.4% to 14.4% (RSD) for the both studied analytes. The coefficient of determination (R-2) values were >= 0.999 (n = 3).

  • 98.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Brooklyn College, US.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Regulatory Traits in Cultural Evolution2012In: Proceedings of WiVACE 2012, 2012, p. 1-9Conference paper (Refereed)
    Abstract [en]

    We call "regulatory traits" those cultural traits that are transmitted through cultural interactions and, at the same time, change individual behaviors directly influencing the outcome of future cultural interactions. The cultural dynamics of some of those traits are studied through simple simulations. In particular, we consider the cultural evolution of traits determining the propensity to copy, the number of potential demonstrators from whom one individual may copy, and conformist versus anti conformist attitudes. Our results show that regulatory traits generate peculiar dynamics that may explain complex human cultural phenomena. We discuss how the existence and importance of regulatory traits in cultural evolution impact on the analogy between genetic and cultural evolution and therefore on the possibility of using evolutionary biology inspired models to study human cultural dynamics.

  • 99.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    The logic of fashion cycles2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 3, p. e32541-Article in journal (Refereed)
    Abstract [en]

    Many cultural traits exhibit volatile dynamics, commonly dubbed fashions or fads. Here we show that realistic fashion-like dynamics emerge spontaneously if individuals can copy others' preferences for cultural traits as well as traits themselves. We demonstrate this dynamics in simple mathematical models of the diffusion, and subsequent abandonment, of a single cultural trait which individuals may or may not prefer. We then simulate the coevolution between many cultural traits and the associated preferences, reproducing power-law frequency distributions of cultural traits (most traits are adopted by few individuals for a short time, and very few by many for a long time), as well as correlations between the rate of increase and the rate of decrease of traits (traits that increase rapidly in popularity are also abandoned quickly and vice versa). We also establish that alternative theories, that fashions result from individuals signaling their social status, or from individuals randomly copying each other, do not satisfactorily reproduce these empirical observations.

  • 100. Acevedo, Nathalie
    et al.
    Bornacelly, Adriana
    Mercado, Dilia
    Unneberg, Per
    Stockholm University, Science for Life Laboratory (SciLifeLab). Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Mittermann, Irene
    Valenta, Rudolf
    Kennedy, Malcolm
    Scheynius, Annika
    Caraballo, Luis
    Genetic Variants in CHIA and CHI3L1 Are Associated with the IgE Response to the Ascaris Resistance Marker ABA-1 and the Birch Pollen Allergen Bet v 12016In: plos one, ISSN 1932-6203, Vol. 11, no 12, article id e0167453Article in journal (Refereed)
    Abstract [en]

    Helminth infections and allergic diseases are associated with IgE hyperresponsiveness but the genetics of this phenotype remain to be defined. Susceptibility to Ascaris lumbricoides infection and antibody levels to this helminth are associated with polymorphisms in locus 13q33-34. We aimed to explore this and other genomic regions to identify genetic variants associated with the IgE responsiveness in humans. Forty-eight subjects from Cartagena, Colombia, with extreme values of specific IgE to Ascaris and ABA-1, a resistance marker of this nematode, were selected for targeted resequencing. Burden analyses were done comparing extreme groups for IgE values. One-hundred one SNPs were genotyped in 1258 individuals of two well-characterized populations from Colombia and Sweden. Two low-frequency coding variants in the gene encoding the Acidic Mammalian Chitinase (CHIA rs79500525, rs139812869, tagged by rs10494133) were found enriched in high IgE responders to ABA-1 and confirmed by genetic association analyses. The SNP rs4950928 in the Chitinase 3 Like 1 gene (CHI3L1) was associated with high IgE to ABA-1 in Colombians and with high IgE to Bet v 1 in the Swedish population. CHIA rs10494133 and ABDH13 rs3783118 were associated with IgE responses to Ascaris. SNPs in the Tumor Necrosis Factor Superfamily Member 13b gene (TNFSF13B) encoding the cytokine B cell activating Factor were associated with high levels of total IgE in both populations. This is the first report on the association between low-frequency and common variants in the chitinases- related genes CHIA and CHI3L1 with the intensity of specific IgE to ABA-1 in a population naturally exposed to Ascaris and with Bet v 1 in a Swedish population. Our results add new information about the genetic influences of human IgE responsiveness; since the genes encode for enzymes involved in the immune response to parasitic infections, they could be helpful for understanding helminth immunity and allergic responses. We also confirmed that TNFSF13B has an important and conserved role in the regulation of total IgE levels, which supports potential evolutionary links between helminth immunity and allergic response.

1234567 51 - 100 of 34676
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf