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  • 1.
    Aagaard, Sunniva M. D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Greilhuber, Johann
    University of Vienna, Department of Systematic and Evolutionary Botany.
    Zhang, Xian-Chun
    Institute of Botany,Chinese Academy of Sciences .
    Wikström, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Occurrence and evolutionary origins of polyploids in the club moss genus Diphasiastrum (Lycopodiaceae)2009In: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 52, no 3, 746-754 p.Article in journal (Refereed)
    Abstract [en]

    Two polyploid taxa are commonly recognized in the genus Diphasiastrum, D. wightianum from Asia and D. zanclophyllum from South Africa and Madagascar. Here we present results from Feulgen DNA image densitometry analyses providing the first evidence for the polyploid origin of D. zanclophyllum. Reported for the first time is also data confirming that D. multispicatum and D. veitchii, representing putative parent lineages for D. wightianum, are diploids. Phylogenetic analyses of nuclear regions RPB2, LEAFY and LAMB4 reveal that putative tetraploid accessions are of allopolyploid origin. Diphasiastrum zanclophyllum shows close relationships to the North American taxon D. digitatum on the maternal side, but the paternal relationship is less clear. Two accessions from Asia, both found to be polyploid, have D. veitchii as maternal parent, whereas the paternal paralogs show relationships to D. multispicatum and D. tristachyum, respectively. None of these parental combinations have previously been hypothesized.

  • 2.
    Aagaard, Sunniva Margrethe Due
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Reticulate Evolution in Diphasiastrum (Lycopodiaceae)2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis relationships and the occurrence of reticulate evolutionary events in the club moss genus Diphasiastrum are investigated. Diphasiastrum is initially established as a monophyletic group within Lycopodiaceae using non recombinant chloroplast sequence data. Support is obtained for eight distinct parental lineages in Diphasiastrum, and relationships among the putative parent taxa in the hypothesized hybrid complexes; D. alpinum, D. complanatum, D. digitatum, D. multispicatum, D. sitchense, D. tristachyum and D. veitchii are presented.

    Feulgen DNA image densitometry data and sequence data obtained from three nuclear regions, RPB2, LEAFY and LAMB4, were used to infer the origins of three different taxa confirmed to be allopolyploid; D. zanclophyllum from South Africa, D. wightianum from Malaysia and an undescribed taxon from China. The two Asian polyploids have originated from two different hybrid combinations, D. multispicatum x D. veitchii and D. tristachyum x D. veitchii. Diphasiastrum zanclophyllum originates from a cross between D. digitatum and an unidentified diploid taxon.

    The occurrence of three homoploid hybrid combinations commonly recognized in Europe, D. alpinum x D. complanatum, D. alpinum x D. tristachyum and D. complanatum x D. tristachyum, are verified using the same three nuclear regions. Two of the three hybrid combinations are also shown to have originated from reciprocal crosses. Admixture analyses performed on an extended, dataset similarly identified predominately F1 hybrids and backcrosses. The observations and common recognition of hybrid species in the included populations are hence most likely due to frequent observations of neohybrids in hybrid zones. Reticulate patterns are, however, prominent in the presented dataset. Hence future studies addressing evolutionary and ecological questions in Diphasiastrum should emphasize the impact of gene flow between parent lineages rather than speciation as the result of hybridization.

  • 3.
    Aagaard, Sunniva M.D.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Department of Evolution, Genomics and Systematics.
    Gyllenstrand, Niclas
    Wikström, Niklas
    Homoploid hybridization in Central European Diphasiastrum (Lycopodiaceae).Manuscript (Other academic)
    Abstract [en]

    Three species of homoploid hybrid origin are commonly recognized among Central European Diphasiastrum, and reticulate evolutionary events have for a long time been acknowledged as an important factor contributing to the species count in the genus. Presented evidence obtained from molecular data has until recently been scarce and inconclusive. Recent studies have, however, documented reticulate phylogenetic patterns involving all putative parental combinations reported from Central Europe. Reciprocal crosses involving the same parental combinations have also been confirmed. In order to further explore these putative reticulate events, admixture analyses using a Bayesian approach as implemented in the program NewHybrids are conducted on an expanded dataset obtained from six Central European populations from where putative hybrid taxa are reported. A majority of the accessions included in the analyses were inferred to represent pure bred D. alpinum, D. complanatum, D. tristachyum, F1 hybrids, F2 hybrids or backcrosses with one of the parent species. Accessions displaying ambiguous classification were found in both allopatric parent populations as well as in Central European hybrid populations. Presented results indicate the presence of frequently occurring hybrid zones with first and second generation hybrids as well as backcrosses.

  • 4.
    Aagaard, Sunniva M.D.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Vogel, Johannes C.
    Wikström, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics.
    Resolving maternal relationships in the clubmoss genus Diphasiastrum (Lycopodiaceae)2009In: Taxon, ISSN 0040-0262, Vol. 58, no 3, 835-848 p.Article in journal (Refereed)
    Abstract [en]

    Diphasiastrum comprises 20-30 species. In addition to a number of species with a circumboreal distribution, several island endemics and putative diploid hybrid species contribute to the diversity of the group. To assess the integrity and relationships of the recognized species, a global phylogeny of Diphasiastrum is constructed using five chloroplast regions comprising ~9000 bp. Six monophyletic groups are identified. Accessions identified as hybrid species cluster in all but one case together with one of its putative parents. Two microsatellite loci are identified, and allelic information combined with sequence information is found diagnostic for the three putative parental taxa in the Central Europe hybrid complexes. Haplotype screening is performed on six Central European populations, from where one or more putative diploid hybrid species have been reported to grow in sympatry with their parent species. The most common parental haplotypes are identified in all populations. Additional intraspecific variation, restricted to single populations, is identified in all sympatric populations at very low frequencies. Taking the low degree of sequence and microsatellite variation into consideration, the acknowledged morphological diversity in Central Europe is probably best explained by phenotypic plasticity, ancestral polymorphisms or relatively recent events of reticulate evolution.

  • 5.
    Aalberg Haugen, Inger M.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Berger, David
    Stockholm University, Faculty of Science, Department of Zoology. Uppsala University, Sweden.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    The evolution of alternative developmental pathways: footprints of selection on life-history traits in a butterfly2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 7, 1377-1388 p.Article in journal (Refereed)
    Abstract [en]

    Developmental pathways may evolve to optimize alternative phenotypes across environments. However, the maintenance of such adaptive plasticity under relaxed selection has received little study. We compare the expression of life-history traits across two developmental pathways in two populations of the butterfly Pararge aegeria where both populations express a diapause pathway but one never expresses direct development in nature. In the population with ongoing selection on both pathways, the difference between pathways in development time and growth rate was larger, whereas the difference in body size was smaller compared with the population experiencing relaxed selection on one pathway. This indicates that relaxed selection on the direct pathway has allowed life-history traits to drift towards values associated with lower fitness when following this pathway. Relaxed selection on direct development was also associated with a higher degree of genetic variation for protandry expressed as within-family sexual dimorphism in growth rate. Genetic correlations for larval growth rate across sexes and pathways were generally positive, with the notable exception of correlation estimates that involved directly developing males of the population that experienced relaxed selection on this pathway. We conclude that relaxed selection on one developmental pathway appears to have partly disrupted the developmental regulation of life-history trait expression. This in turn suggests that ongoing selection may be responsible for maintaining adaptive developmental regulation along alternative developmental pathways in these populations.

  • 6.
    Aalberg Haugen, Inger M.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Diapause induction and relaxed selection on alternative developmental pathways in a butterfly2015In: Journal of Animal Ecology, ISSN 0021-8790, E-ISSN 1365-2656, Vol. 84, no 2, 464-472 p.Article in journal (Refereed)
    Abstract [en]

    Seasonal phenotypic plasticity entails differential trait expression depending on the time of season. The facultative induction of winter diapause in temperate insects is a developmental switch mechanism often leading to differential expression in life-history traits. However, when there is a latitudinal shift from a bivoltine to univoltine life cycle, selection for pathway-specific expression is disrupted, which may allow drift towards less optimal trait values within the non-selected pathway. We use field- and experimental data from five Swedish populations of Pararge aegeria to investigate latitudinal variation in voltinism, local adaptation in the diapause switch and footprints of selection on pathway-specific regulation of life-history traits and sexual dimorphism in larval development. Field data clearly illustrated how natural populations gradually shift from bivoltinism to univoltinism as latitude increases. This was supported experimentally as the decrease in direct development at higher latitudes was accompanied by increasing critical daylengths, suggesting local adaptation in the diapause switch. The differential expression among developmental pathways in development time and growth rate was significantly less pronounced in univoltine populations. Univoltine populations showed no significant signs of protandry during larval development, suggesting that erosion of the direct development pathway under relaxed selection has led to the loss of its sex-specific modifications.

  • 7.
    Aalberg Haugen, Inger M.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    The development and expression of seasonal polyphenism in life-history traits in the butterfly Pararge aegeriaManuscript (preprint) (Other academic)
  • 8.
    Aalberg Haugen, Inger M.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gotthard, Karl
    Stockholm University, Faculty of Science, Department of Zoology.
    Latitudinal phenological adaptation: diapause induction and differentiation between alternative developmental pathways in a butterflyManuscript (preprint) (Other academic)
    Abstract [en]

    1. Seasonal phenotypic plasticity entails differential trait expression depending on the time of season. The facultative induction of winter diapause in temperate insects is a developmental switch mechanism often leading to differential expression in life history traits. However, when there is a latitudinal shift from a bivoltine to univoltine life cycle, selection for pathway-specific expression is disrupted, which may allow drift towards less optimal trait values within the non-selected pathway.

    2. We use field- and experimental data from five Swedish populations of Pararge aegeria to investigate latitudinal variation in voltinism, local adaptation in the diapause switch, and footprints of selection on pathway-specific regulation of life history traits and sexual dimorphism in larval development.

    3. Field data clearly illustrated how natural populations gradually shift from bivoltinism to univoltinism as latitude increases. This was supported experimentally as the decrease in direct development at higher latitudes was accompanied by increasing critical daylengths, suggesting local adaptation in the diapause switch.

    4. The differential expression among developmental pathways in development time and growth rate was significantly less pronounced in univoltine populations. Univoltine populations showed no significant signs of protandry during larval development, suggesting that erosion of the direct development pathway under relaxed selection has led to the loss of its sex-specific modifications.

  • 9.
    Aalberg Haugen, Inger Marie
    Stockholm University, Faculty of Science, Department of Zoology.
    The diapause switch: Evolution of alternative developmental pathways in a butterfly2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Diapause decision is a classic example of a threshold switch mechanism with cascading effects on morphology, behaviour and life-history traits. This thesis addresses the downstream effects of the insect diapause switch, with the main focus on pathway-specific regulation of life-history traits, using the speckled wood butterfly (Pararge aegeria) as a study species. The ultimate pathway decision is made towards the end of larval development and allows the larvae to take into account up-to-date information from the environment about future conditions (Paper I, IV). However, already from an early point in development the larvae are sensitive to environmental cues and continuously adjust their growth trajectory in accordance to current information about the environmental conditions to be expected in future (Paper IV). An asymmetry in the ability to change from one developmental pathway to another at a late point in larval development suggests that the diapause and the direct pathway require different physiological preparations (Paper IV). Pathway-specific regulation of traits downstream of the diapause switch is maintained by ongoing selection. When the direct pathway is not regularly expressed, as with a shift from bivoltinism to univoltinism, relaxed selection on the unexpressed pathway leads to genetic drift and loss of protandry (Paper II, III). Natural populations display local adaptations in the diapause switch with an increase in critical daylengths as there is a gradual shift from bivoltinism to univoltinism (Paper III). This thesis highlights two aspects of the diapause decision, the determination of how and when this decision is made as well as the way the resulting pathways are moulded by selection in order to produce adaptive seasonal polyphenism in life-history traits.

  • 10. Aaldering, L. J.
    et al.
    Poongavanam, V.
    Langkjær, N.
    Natarajan Arul, Murugan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Jørgensen, P. T.
    Wengel, J.
    Veedu, R. N.
    Development of an Efficient G-Quadruplex-Stabilised Thrombin-Binding Aptamer Containing a Three-Carbon Spacer Molecule2017In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 18, no 8, 755-763 p.Article in journal (Refereed)
    Abstract [en]

    The thrombin-binding aptamer (TBA), which shows anticoagulant properties, is one of the most studied G-quadruplex-forming aptamers. In this study, we investigated the impact of different chemical modifications such as a three-carbon spacer (spacer-C3), unlocked nucleic acid (UNA) and 3′-amino-modified UNA (amino-UNA) on the structural dynamics and stability of TBA. All three modifications were incorporated at three different loop positions (T3, T7, T12) of the TBA G-quadruplex structure to result in a series of TBA variants and their stability was studied by thermal denaturation; folding was studied by circular dichroism spectroscopy and thrombin clotting time. The results showed that spacer-C3 introduction at the T7 loop position (TBA-SP7) significantly improved stability and thrombin clotting time while maintaining a similar binding affinity as TBA to thrombin. Detailed molecular modelling experiments provided novel insights into the experimental observations, further supporting the efficacy of TBA-SP7. The results of this study could provide valuable information for future designs of TBA analogues with superior thrombin inhibition properties. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  • 11. Aarrestad, P. A.
    et al.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Masunga, G.
    Skarpe, C.
    Vegetation: Between Soils and Herbivores2014In: Elephants and Savanna Woodland Ecosystems: A Study from Chobe National Park, Botswana / [ed] Christina Skarpe, Johan T. du Toit and Stein R. Moe, Wiley-Blackwell, 2014, 61-88 p.Chapter in book (Refereed)
    Abstract [en]

    The vegetation of the study area in Chobe National Park is influenced by a range of factors, including inundation by the Chobe River, soil moisture and fertility, and the impacts of different-size grazers and browsers. This chapter focuses on how the structure and species composition of the present vegetation in northern Chobe National Park is related to recent herbivory by elephants, as agents shaping the vegetation, and by mesoherbivores acting as controllers or responders, along with abiotic controllers such as soil type and distance to the river. In the study, a two-way indicator species analysis classified the vegetation data into four more or less distinct plant community groups (i) Baikiaea plurijuga-Combretum apiculatum woodland, (ii) Combretum mossambicense-Friesodielsia obovata wooded shrubland, (iii) Capparis tomentosa-Flueggea virosa shrubland and (iv) Cynodon dactylon-Heliotropium ovalifolium floodplain, named after the TWINSPAN indicator or preferential species with high cover, and the relative amount of shrubs and trees.

  • 12. Aarrestad, P. A.
    et al.
    Masunga, G. S.
    Hytteborn, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Pitlagano, M. L.
    Marokane, W.
    Skarpe, C.
    Influence of soil, tree cover and large herbivores on field layer vegetation along a savanna landscape gradient in northern Botswana2011In: Journal of Arid Environments, ISSN 0140-1963, E-ISSN 1095-922X, Vol. 75, no 3, 290-297 p.Article in journal (Refereed)
    Abstract [en]

    The response of the field layer vegetation to co-varying resource availability (soil nutrients, light) and resource loss (herbivory pressure) was investigated along a landscape gradient highly influenced by elephants and smaller ungulates at the Chobe River front in Botswana. TWINSPAN classification was used to identify plant communities. Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to explore the vegetation-environment relationships. Four plant communities were described: Panicum maximum woodland, Tribulus terrestris woodland/shrubland, Chloris virgata shrubland and Cynodon dactylon floodplain. Plant height, species richness and diversity decreased with increasing resource availability and resource loss. The species composition was mainly explained by differences in soil resources, followed by variables related to light availability (woody cover) and herbivory, and by interactions between these variables. The vegetation structure and species richness, on the other hand, followed the general theories of vegetation responses to herbivory more closely than resource related theories. The results suggest a strong interaction between resource availability and herbivory in their influence on the composition, species richness and structure of the plant communities.

  • 13.
    Aarseth Larsson, Kim
    Örebro University, School of Science and Technology, Örebro University, Sweden.
    Inhibition of SIRT1 Alters Apoptotic and Sex Related Genes in Zebrafish (Danio rerio)2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide - dependent deacetylase that belongs to the sirtuin protein family. The protein has been linked to both cancer through its effect on p53 and age related illnesses through its effect on peroxisome proliferator-activated receptor gamma (PPAR-γ). Recent data have shown a correlation between SIRT1, male fertility and spermatogenesis. Because the mechanism of sex differentiation in zebrafish is still not wellunderstood the sirt1 gene is an attractive target to study in order to improve our understanding of this topic. Zebrafish of different age were exposed to various concentrations of EX-527 toinhibit the SIRT1 protein. This was followed by qRT-PCR analysis of apoptotic and sex-related genes. Both apoptotic and sex-related gene expression levels were affected by the exposure. There were differences in genes that were affected, both between the concentrations of EX-527, and between the ages of the exposed zebrafish. The male- specific gene sexdetermining region Y box 9A (sox9a) was down-regulated at both studied EX-527 concentrations in both zebrafish larvae and juveniles. The exposure of the EX-527 resulted in no significant difference in sex-ratio. Further studies are required to describe the pathway for SIRT1 gene regulation in zebrafish.

  • 14.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vare, Daniel
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Motwani, Hitesh V.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jenssen, Dag
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quantification of the mutagenic potency and repair of glycidol-induced DNA lesions2016In: Mutation research. Genetic toxicology and environmental mutagenesis, ISSN 1383-5718, E-ISSN 1879-3592, Vol. 805, 38-45 p.Article in journal (Refereed)
    Abstract [en]

    Glycidol (Gly) is an electrophilic low-molecular weight epoxide that is classified by IARC as probably carcinogenic to humans. Humans might be exposed to Gly from food, e.g. refined vegetable oils, where Gly has been found as a food process contaminant. It is therefore important to investigate and quantify the genotoxicity of Gly as a primary step towards cancer risk assessment of the human exposure. Here, quantification of the mutagenic potency expressed per dose (AUC: area under the concentration time curve) of Gly has been performed in Chinese hamster ovary (CHO) cells, using the HPRT assay. The dose of Gly was estimated in the cell exposure medium by trapping Gly with a strong nucleophile, cob(I)alamin, to form stable cobalamin adducts for analysis by LC-MS/MS. Gly was stable in the exposure medium during the time for cell treatment, and thus the dose in vitro is the initial concentration x cell treatment time. Gly induced mutations in the hprt-gene at ante of 0.08 +/- 0:01 mutations/10(5) cells/mMh. Through comparison with the effect of ionizing radiation in the same system a relative mutagenic potency of 9.5 rad-eq./mMh was obtained, which could be used for comparison of genotoxicity of chemicals and between test systems and also in procedures for quantitative cancer risk assessment. Gly was shown to induce strand breaks, that were repaired by base excision repair. Furthermore, Gly-induced lesions, present during replication, were found to delay the replication fork elongation. From experiments with repair deficient cells, homologous recombination repair and the ERCC1-XPF complex were indicated to be recruited to support in the repair of the damage related to the stalled replication elongation. The type of DNA damage responsible for the mutagenic effect of Gly could not be concluded from the present study.

  • 15. Abalaka, J. L.
    et al.
    Ottosson, Ulf
    Tende, Talatu
    Larson, Keith W.
    Rock Firefinch Lagonosticta sanguinodorsalis in the Mandara Mountains, north-east Nigeria: a new subspecies?2010In: African Bird Club Bulletin, ISSN 1352-481X, Vol. 17, no 2, 210-211 p.Article in journal (Refereed)
    Abstract [fr]

    L’Amarante des rochers Lagonosticta sanguinodorsalis dans les Monts Mandara, Nigeria du sud-est: une nouvelle sous-espèce ? Nous fournissons une description d’un mâle et d’une femelle, ainsi que desphotos d’un mâle, d’un amarante capturé dans les Monts Mandara, au nord-est du Nigeria. Le plumage et le cri de cet amarante sont identiques à ceux de l’Amarante des rochers Lagonosticta sanguinodorsalis, une espèce précédemment rapportée de la zone, excepté que le mâle n’a pas la couronne grise typique de l’espèce. Des travaux supplémentaires sur le terrain sont nécessaires pour déterminer s’il agit d’un individu aberrant ou d’une population de l’Amarante des rochers morphologiquement distincte.

  • 16.
    Abarenkov, Kessy
    et al.
    Univ Tartu, Nat Hist Museum, Tartu, Estonia..
    Adams, Rachel I.
    Univ Calif Berkeley, Plant & Microbial Biol, Berkeley, CA 94720 USA..
    Irinyi, Laszlo
    Westmead Hosp, Ctr Infect Dis & Microbiol, Mol Mycol Res Lab, Sydney Med Sch, Sydney, NSW, Australia.;Univ Sydney, Marie Bashir Inst Infect Dis & Biosecur, Sydney, NSW, Australia.;Westmead Inst Med Res, Westmead, NSW, Australia..
    Agan, Ahto
    Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia..
    Ambrosio, Elia
    Univ Tartu, Nat Hist Museum, Tartu, Estonia.;Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.;Via Calamandrei 2, I-53035 Siena, Italy..
    Antonelli, Alexandre
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden.;Gothenburg Bot Garden, Carl Skottsbergs Gata 22A, S-41319 Gothenburg, Sweden..
    Bahram, Mohammad
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology. Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia.
    Bengtsson-Palme, Johan
    Univ Gothenburg, Sahlgrenska Acad, Dept Infect Dis, Guldhedsgatan 10, S-41346 Gothenburg, Sweden..
    Bok, Gunilla
    SP Tech Res Inst Sweden, Box 857, S-50115 Boras, Sweden..
    Cangren, Patrik
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Coimbra, Victor
    Univ Fed Pernambuco UFPE, Dept Micol, CCB, Av Prof Nelson Chaves S-N, BR-50670901 Recife, PE, Brazil..
    Coleine, Claudia
    Univ Tuscia, Dept Ecol & Biol Sci, I-01100 Viterbo, Italy..
    Gustafsson, Claes
    Univ Gothenburg, Herbarium GB, Box 461, S-40530 Gothenburg, Sweden..
    He, Jinhong
    Chinese Acad Sci, South China Bot Garden, 723 Xingke Rd, Guangzhou 510650, Guangdong, Peoples R China..
    Hofmann, Tobias
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Kristiansson, Erik
    Chalmers, Dept Math Sci, S-41296 Gothenburg, Sweden..
    Larsson, Ellen
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Larsson, Tomas
    Univ Gothenburg, Dept Marine Sci, Box 460, S-40530 Gothenburg, Sweden..
    Liu, Yingkui
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Martinsson, Svante
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Meyer, Wieland
    Westmead Hosp, Ctr Infect Dis & Microbiol, Mol Mycol Res Lab, Sydney Med Sch, Sydney, NSW, Australia.;Westmead Inst Med Res, Westmead, NSW, Australia..
    Panova, Marina
    Univ Gothenburg, Dept Marine Sci Tjarno, S-45296 Stromstad, Sweden..
    Pombubpa, Nuttapon
    Univ Calif Riverside, Dept Plant Pathol & Microbiol, Riverside, CA 92521 USA.;Univ Calif Riverside, Inst Integrat Genome Biol, Riverside, CA 92521 USA..
    Ritter, Camila
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Ryberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
    Svantesson, Sten
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Scharn, Ruud
    Univ Gothenburg, Dept Earth Sci, Box 460, S-40530 Gothenburg, Sweden..
    Svensson, Ola
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Töpel, Mats
    Univ Gothenburg, Dept Marine Sci, Box 460, S-40530 Gothenburg, Sweden..
    Unterseher, Martin
    Ernst Moritz Arndt Univ Greifswald, Inst Bot & Landscape Ecol, Soldmannstr 15, D-17487 Greifswald, Germany..
    Visagie, Cobus
    Agr & Agri Food Canada, Biodivers Mycol, 960 Carling Ave, Ottawa, ON K1A 0C6, Canada.;Univ Ottawa, Dept Biol, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada..
    Wurzbacher, Christian
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Taylor, Andy F. S.
    James Hutton Inst, Aberdeen AB15 8QH, Scotland.;Univ Aberdeen, Inst Biol & Environm Sci, Cruickshank Bldg, Aberdeen AB24 3UU, Scotland..
    Köljalg, Urmas
    Univ Tartu, Nat Hist Museum, Tartu, Estonia.;Univ Tartu, Inst Ecol & Earth Sci, Tartu, Estonia..
    Schriml, Lynn
    Univ Maryland, Sch Med, Dept Epidemiol & Publ Hlth, Baltimore, MD 21201 USA.;Univ Maryland, Sch Med, Inst Genome Sci, Baltimore, MD 21201 USA..
    Nilsson, R. Henrik
    Univ Gothenburg, Dept Biol & Environm Sci, Box 461, S-40530 Gothenburg, Sweden..
    Annotating public fungal ITS sequences from the built environment according to the MIxS-Built Environment standard - a report from a May 23-24, 2016 workshop (Gothenburg, Sweden)2016In: MycoKeys, ISSN 1314-4057, E-ISSN 1314-4049, no 16, 1-15 p.Article in journal (Refereed)
    Abstract [en]

    Recent molecular studies have identified substantial fungal diversity in indoor environments. Fungi and fungal particles have been linked to a range of potentially unwanted effects in the built environment, including asthma, decay of building materials, and food spoilage. The study of the built mycobiome is hampered by a number of constraints, one of which is the poor state of the metadata annotation of fungal DNA sequences from the built environment in public databases. In order to enable precise interrogation of such data - for example, "retrieve all fungal sequences recovered from bathrooms" - a workshop was organized at the University of Gothenburg (May 23-24, 2016) to annotate public fungal barcode (ITS) sequences according to the MIxS-Built Environment annotation standard (http:// gensc.org/ mixs/). The 36 participants assembled a total of 45,488 data points from the published literature, including the addition of 8,430 instances of countries of collection from a total of 83 countries, 5,801 instances of building types, and 3,876 instances of surface-air contaminants. The results were implemented in the UNITE database for molecular identification of fungi (http://unite.ut.ee) and were shared with other online resources. Data obtained from human/animal pathogenic fungi will furthermore be verified on culture based metadata for subsequent inclusion in the ISHAM-ITS database (http:// its. mycologylab.org).

  • 17. Abbasi, Arshad Mehmood
    et al.
    Khan, Mir Ajab
    Khan, Nadeem
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Shah, Munir H
    Ethnobotanical survey of medicinally important wild edible fruits species used by tribal communities of Lesser Himalayas-Pakistan2013In: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 148, no 2, 528-536 p.Article in journal (Refereed)
    Abstract [en]

    Ethnopharmacological relevance: Present survey was conducted to explore ethnomedicinal uses and cultural importance of wild edible fruits species by the inhabitants of Lesser Himalayas-Pakistan. Materials and methods: Information was obtained through informed consent semi-structured interviews, questionnaires, market survey, focus group conversation, unceremonious dialogue and village walks with key informants. Cultural significance of each species was calculated based on use report by participants at each study site. Results: A total of 35 wild edible fruits belonging to 21 genera and 17 families were used for the treatment of various ailments and consumed. Rosaceae was found dominating family with (8 spp.), followed by Moraceae (6 spp.), Rhamnaceae (5 spp.), Palmae and Vitaceae (2 spp. each) and remaining families were represented by one species each. Fruits (48%) were found highly utilized plant parts, followed by leaves (34%), bark, flowers and seeds (4% each), branches, latex and roots (2% each). Water was used as a medium for preparation while milk, ghee, oil, egg and butter are used for application. Modes of preparation were fall into seven categories like fresh parts eaten raw (38%), powder (24%), decoction (20%), extract (12 %), paste (4%), juice and latex (2% each). Based on cultural important index (CI) Morus nigra was found most significant species within top ten fruit plants followed by Morus alba, Olea ferruginea, Berberis lycium, Pyrus pashia, Ficus carica, Ficus palmata, Ziziphus mauritiana, Diospyros lotus and Ziziphus nummularia. Conclusions: Traditional uses of wild edible plant depend mainly on socio-economic factors rather than climatic conditions or wealth of flora. Use reports and citation demonstrated that there is a common cultural heritage regarding the gathered food plants. Further investigation is required for Antioxidant study, essential and toxic components, pharmacological applications; dietary requirements and biotechnological techniques to improve yields.

    (C) 2013 Elsevier Ireland Ltd. All rights reserved.

  • 18.
    Abbasi, Saeed
    et al.
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Jansson, Anders
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sellgren, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Olofsson, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Particle Emissions From Rail Traffic: A Literature Review2013In: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537, Vol. 43, no 23, 2511-2544 p.Article, review/survey (Refereed)
    Abstract [en]

    Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and nonexhaust particle emissions are considered when examining particle characteristics such as PM10, and PM2.5 concentration levels, size, morphology, composition, and adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. The authors find that only a few limited studies have examined the adverse health effects of nonexhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

  • 19.
    Abbassi, Nasrollah
    et al.
    Univ Zanjan, Dept Geol, Fac Sci, Zanjan, Iran..
    Kundrat, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ataabadi, Majid Mirzaie
    Univ Zanjan, Dept Geol, Fac Sci, Zanjan, Iran..
    Ahlberg, Per E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala Univ, Sub Dept Evolut & Dev, Evolutionary Biol Ctr, Dept Organismal Biol, Uppsala, Sweden..
    Avian ichnia and other vertebrate trace fossils from the Neogene Red Beds of Tarom valley in north-western Iran2016In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 28, no 8, 1075-1089 p.Article in journal (Refereed)
    Abstract [en]

    The Neogene Red Beds of the Tarom valley (north-western Iran) include conglomerate, sandstone, marl and gypsum. Avian and mammal footprints were discovered in one of the sandstone layers at the base of a third Miocene stratigraphical unit in the Gilankesheh area located in the east Tarom valley. The avian ichnia include Aviadactyla vialovi, Avipeda filiportatis, Charadriipeda disjuncta, Charadriipeda isp. A and B and cf. Ornithotarnocia lambrechti. Bird feeding traces are preserved as bilobate, loop-shaped, sinusoidal and ring-like traces. We have also identified a reticulate texture of sole scale imprints in some of the avian ichnia. Two mammal footprints of camelid-like artiodactyls are also present with the avian ichno-assemblage.

  • 20.
    Abbott, Jessica K.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Intra-locus sexual conflict and sexually antagonistic genetic variation in hermaphroditic animals2011In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 278, no 1703, 161-169 p.Article, review/survey (Refereed)
    Abstract [en]

    Intra-locus sexual conflict results when sex-specific selection pressures for a given trait act against the intra-sexual genetic correlation for that trait. It has been found in a wide variety of taxa in both laboratory and natural populations, but the importance of intra-locus sexual conflict and sexually antagonistic genetic variation in hermaphroditic organisms has rarely been considered. This is not so surprising given the conceptual and theoretical association of intra-locus sexual conflict with sexual dimorphism, but there is no a priori reason why intra-locus sexual conflict cannot occur in hermaphroditic organisms as well. Here, I discuss the potential for intra-locus sexual conflict in hermaphroditic animals and review the available evidence for such conflict, and for the existence of sexually antagonistic genetic variation in hermaphrodites. I argue that mutations with asymmetric effects are particularly likely to be important in mediating sexual antagonism in hermaphroditic organisms. Moreover, sexually antagonistic genetic variation is likely to play an important role in inter-individual variation in sex allocation and in transitions to and from gonochorism (separate sexes) in simultaneous hermaphrodites. I also describe how sequential hermaphrodites may experience a unique form of intra-locus sexual conflict via antagonistic pleiotropy. Finally, I conclude with some suggestions for further research.

  • 21.
    Abbott, Jessica K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Bedhomme, Stéphanie
    Evolutionary Systems Virology Group, University of Valencia.
    Chippindale, Adam K.
    Biology Department, Queen's University.
    Sexual conflict in wing size and shape in Drosophila melanogaster2010In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 23, no 9, 1989-1997 p.Article in journal (Refereed)
    Abstract [en]

    Intralocus sexual conflict occurs when opposing selection pressures operate on loci expressed in both sexes, constraining the evolution of sexual dimorphism and displacing one or both sexes from their optimum. We eliminated intralocus conflict in Drosophila melanogaster by limiting transmission of all major chromosomes to males, thereby allowing them to win the intersexual tug-of-war. Here, we show that this male-limited (ML) evolution treatment led to the evolution (in both sexes) of masculinized wing morphology, body size, growth rate, wing loading, and allometry. In addition to more male-like size and shape, ML evolution resulted in an increase in developmental stability for males. However, females expressing ML chromosomes were less developmentally stable, suggesting that being ontogenetically more male-like was disruptive to development. We suggest that sexual selection over size and shape of the imago may therefore explain the persistence of substantial genetic variation in these characters and the ontogenetic processes underlying them.

  • 22.
    Abbott, Jessica K.
    et al.
    Queen's University.
    Bensch, S.
    Lund University.
    Gosden, Thomas P.
    Lund University.
    Svensson, Erik I.
    Lund University.
    Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations2008In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 17, no 6, 1597-1604 p.Article in journal (Refereed)
    Abstract [en]

    The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F(ST) values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F(ST )(selected) > F(ST )(neutral)], or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [F(ST) (selected) < F(ST) (neutral)]. Here, we compared F(ST) values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F(ST) values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.

  • 23.
    Abbott, Jessica K.
    et al.
    Queen's University.
    Gosden, Thomas P.
    Lund University.
    Correlated morphological and colour differences among females of the damselfly Ischnura elegans2009In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 34, no 3, 378-386 p.Article in journal (Refereed)
    Abstract [en]

    1. The female-limited colour polymorphic damselfly Ischnura elegans has proven to be an interesting study organism both as an example of female sexual polymorphism, and in the context of the evolution of colour polymorphism. The study of colour polymorphism can also have broader applications as a model of speciation processes.

    2. Previous research suggests that there exist correlations between colour morph and other phenotypic traits, and that the different female morphs in I. elegans may be pursuing alternative phenotypically integrated strategies. However, previous research on morphological differences in southern Swedish individuals of this species was only carried out on laboratory-raised offspring from a single population, leaving open the question of how widespread such differences are.

    3. We therefore analysed multi-generational data from 12 populations, investigating morphological differences between the female morphs in the field, differences in the pattern of phenotypic integration between morphs, and quantified selection on morphological traits.

    4. We found that consistent morphological differences did indeed exist between the morphs across all study populations, confirming that the previously observed differences were not simply a laboratory artefact.  We also found, somewhat surprisingly, that despite the existence of sexual dimorphism in body size and shape, patterns of phenotypic integration differed most between the morphs and not between the sexes. Finally, linear selection gradients showed that female morphology affected fecundity differently between the morphs.

    5. We discuss the relevance of these results to the male mimicry hypothesis and to the existence of potential ecological differences between the morphs.

  • 24.
    Abbott, Jessica K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morrow, Edward H.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Obtaining snapshots of genetic variation using hemiclonal analysis2011In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 26, no 7, 359-368 p.Article, review/survey (Refereed)
    Abstract [en]

    Hemiclones are naturally occurring or artificially produced individuals that share a single specific genetic haplotype. Natural hemiclones are produced via hybridization between two closely related species, whereas hemiclonal analysis in Drosophila is carried out in the laboratory via crosses with artificially created 'clone-generator' females with a specific genetic make-up. Hemiclonal analysis in Drosophila has been applied successfully to date to obtain measures of standing genetic variation for numerous traits. Here, we review the current hemiclonal literature and suggest future directions for hemiclonal research, including its application in molecular and genomic studies, and the adaptation of natural hemiclonal systems to carry out Drosophila-type studies of standing genetic variation.

  • 25.
    Abbott, Jessica K.
    et al.
    Lund University.
    Svensson, Erik I.
    Lund University.
    Ontogeny of sexual dimorphism and phenotypic integration in heritable morphs2008In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 22, no 1, 103-121 p.Article in journal (Refereed)
    Abstract [en]

    In this study we investigated the developmental basis of adult phenotypes in a non-model organism, a polymorphic damselfly (Ischnura elegans) with three female colour morphs. This polymorphic species presents an ideal opportunity to study intraspecific variation in growth trajectories, morphological variation in size and shape during the course of ontogeny, and to relate these juvenile differences to the phenotypic differences of the discrete adult phenotypes; the two sexes and the three female morphs. We raised larvae of different families in individual enclosures in the laboratory, and traced morphological changes during the course of ontogeny. We used principal components analysis to examine the effects of Sex, Maternal morph, and Own morph on body size and body shape. We also investigated the larval fitness consequences of variation in size and shape by relating these factors to emergence success. Females grew faster than males and were larger as adults, and there was sexual dimorphism in body shape in both larval and adult stages. There were also significant effects of both maternal morph and own morph on growth rate and body shape in the larval stage. There were significant differences in body shape, but not body size, between the adult female morphs, indicating phenotypic integration between colour, melanin patterning, and body shape. Individuals that emerged successfully grew faster and had different body shape in the larval stage, indicating internal (non-ecological) selection on larval morphology. Overall, morphological differences between individuals at the larval stage carried over to the adult stage. Thus, selection in the larval stage can potentially result in correlated responses in adult phenotypes and vice versa.

  • 26.
    Abbott, Jessica K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Svensson, Erik I.
    Lund University.
    Morph-specific variation in intersexual genetic correlations in an intra-specific mimicry system2010In: Evolutionary Ecology Research, ISSN 1522-0613, Vol. 12, no 1, 105-118 p.Article in journal (Refereed)
    Abstract [en]

    Background: Positive intersexual genetic correlations are typically viewed as constraining the evolution of sexual dimorphism, when traits are subject to sexually antagonistic selection. Our study species, the damselfly Ischnura elegans, has a female-limited colour polymorphism with three female colour morphs (males are monomorphic), one of which is considered a male mimic.

    Question: Are there morph-specific differences in the magnitude of intersexual genetic correlations in I. elegans? Specifically, do male-mimic (Androchrome) females have higher intersexual genetic correlations for morphological traits than non-mimic (Infuscans) females?

    Methods: We collected copulating pairs in the field and raised offspring from these pairs in the laboratory. We measured five morphological traits in both parent and offspring generations and investigated their heritabilities and genetic correlations.

    Results: We found a negative overall relationship between the degree of sexual dimorphism for a trait and its intersexual genetic correlation. But the magnitude and direction of intersexual genetic correlations depended on the female morph. As expected, male mimic (Androchrome) females had higher intersexual genetic correlations. In addition, the genetic correlations between the morphs were in all cases significantly lower than unity. Male mimic (Androchrome) females had higher mother-son covariances than the non-mimic (Infuscans) morph, and this difference is the proximate explanation for the difference in intersexual genetic correlations between the morphs.

  • 27.
    Abbott, Jessica K.
    et al.
    Lund University.
    Svensson, Erik I.
    Lund University.
    Phenotypic and genetic variation in emergence and development time of a trimorphic damselfly2005In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 18, no 6, 1464-1470 p.Article in journal (Refereed)
    Abstract [en]

    Although colour polymorphisms in adult organisms of many taxa are often adaptive in the context of sexual selection or predation, genetic correlations between colour and other phenotypic traits expressed early in ontogeny could also play an important role in polymorphic systems. We studied phenotypic and genetic variation in development time among female colour morphs in the polymorphic damselfly Ischnura elegans in the field and by raising larvae in a common laboratory environment. In the field, the three different female morphs emerged at different times. Among laboratory-raised families, we found evidence of a significant correlation between maternal morph and larval development time in both sexes. This suggests that the phenotypic correlation between morph and emergence time in the field has a parallel in a genetic correlation between maternal colour and offspring development time. Maternal colour morph frequencies could thus potentially change as correlated responses to selection on larval emergence dates. The similar genetic correlation in male offspring suggests that sex-limitation in this system is incomplete, which may lead to an ontogenetic sexual conflict between selection for early male emergence (protandry) and emergence times associated with maternal morph.

  • 28.
    Abdel Rehim, Abbi
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Abdel Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Screening and determination of drugs in human saliva utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry2013In: BMC Biomedical chromotography, ISSN 0269-3879, E-ISSN 1099-0801, Vol. 27, no 9, 1188-1191 p.Article in journal (Refereed)
    Abstract [en]

    This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C-8-cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS-LC-MS/MS is reported.

  • 29.
    Abdel–Khalik, Jonas
    et al.
    Institute of Mass Spectrometry, College of Medicine, Swansea University.
    Björklund, Erland
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Hansen, Martin
    Department of Civil & Environmental Engineering, Stanford University.
    Simultaneous determination of endogenous steroid hormones in human and animal plasma and serum by liquid or gas chromatography coupled to tandem mass spectrometry2013In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 928, no June, 59-77 p.Article in journal (Refereed)
    Abstract [en]

    Analytical methodologies based on liquid or gas chromatography coupled to tandem mass spectrometry for the simultaneous determination of two or more endogenous steroid hormones in human and animal plasma and serum has received increased attention the last few years. Especially in the clinical setting steroid profiling is of major importance in disease diagnostics. This paper discusses recent findings in such multi-steroid hormone procedures published from 2001 to 2012. The aim was to elucidate possible relationships between chosen analytical technique and the obtained analyte sensitivity for endogenous steroid hormones. By evaluating the success, at which the currently applied techniques have been utilized, more general knowledge on the field is provided. Furthermore the evaluation provides directions in which future studies may be interesting to conduct.

  • 30.
    Abdel-Khalik, Jonas
    et al.
    England.
    Björklund, Erland
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Plattformen för molekylär analys.
    Nielsen, Frederik Knud
    Danmark.
    Hansen, Martin
    Danmark.
    Incorporation of (14)C-cholesterol in human adrenal corticocarcinoma H295R cell line and online-radiodetection of produced (14)C-steroid hormone metabolites2017In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 145, 569-575 p.Article in journal (Refereed)
    Abstract [en]

    This study demonstrates the addition of (14)C-cholesterol to the human cell line H295R will in-situ form radiolabeled steroid hormones allowing for new mechanistic and metabolic insights. The aim of the present study was to in-situ radiolabel steroid hormones from cell line-incorporated (14)C-cholesterol using the OECD guideline 456, H295R steroidogenesis in-vitro assay. Radiodetection of the steroid metabolites of the steroidogenic pathway allows for an improved understanding of the various enzymatic mechanisms involved without necessarily being dependent on quantification. Generated radiolabeled steroids were analyzed using HPLC hyphenated with a Flow Scintillation Analyzer (FSA). H295R cells were incubated with radiolabeled cholesterol and cell media were collected and prepared by solid phase extraction and analyzed with HPLC-FSA. For successful radiolabeling of the steroids in the steroidogenesis of H295R cells, radioactive cholesterol may potentially only need to be added just before the cells are incubated for 72h in well plates. Based on the obtained HPLC-FSA chromatograms, and confirmation of the observations by studies in the literature, a qualitative time profile for the production of steroid hormones was estimated. Multiple radiolabeled steroid hormones were identified by means of analytical standards and UV (ultraviolet) co-chromatography, though the elucidation of multiple metabolites remains unresolved. Although online radiodetection proved to suffer from suboptimal sensitivity, the concept of radiolabeling the steroidogenesis in H295R cells with (14)C-cholesterol and detecting the radiolabeled steroid hormones online was proved and may assist in further toxicological studies.

  • 31.
    Abdel-Rehim, Abbi
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Abdel-Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Evaluation of microextraction by packed sorbent and micro-liquid chromatography-tandem mass spectrometry as a green approach in bioanalysis2013In: BMC Biomedical chromotography, ISSN 0269-3879, E-ISSN 1099-0801, Vol. 27, no 10, 1225-1233 p.Article in journal (Refereed)
    Abstract [en]

    In this study the use of micro-liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was investigated in routine bioanalysis application for separation and quantification of pro-drug AZD6319 (developed for aldezheimer treatment). Microextraction by packed sorbent (MEPS) was used as sample clean-up method. The focus of this study was put on the evaluation of the usability of smaller column diameters such as 1.0 and 0.3mm instead of 2.1mm in bioanalysis application to reduce solvent consumption and sample volumes. Solvent consumption was reduced by 80% when a 1.0mm column was used compared with 2.1mm column. Robustness of the micro-columns in terms of accuracy and precision was investigated. The application of LC-MS/MS for the quantitative analysis of AZD6319 in plasma samples showed good selectivity, accuracy and precision. The coefficients of determination (R-2) were >0.998 for all runs using plasma samples on the studied micro-columns. The inter-day accuracy values for quality control samples ranged from 99 to 103% and from 96 to 105% for 0.3x50mm and 1.0x50mm columns, respectively. The inter-day precision values ranged from 4.0 to 9.0% and from 4.0 to 8.0% for 0.3x50 and 1.0x50mm columns, respectively. In addition the sensitivity was increased by three times using a 1.0mm column compared with 2.1mm. Furthermore, robustness of the micro-columns from different manufacturers was investigated.

  • 32.
    Abderhim, Walid Tajeddinn
    Örebro University, School of Science and Technology, Örebro University, Sweden.
    Morphological Analysis of β-catenin and E-cadherin in Colorectal Cancer2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 33. Abdurahman, Samir
    et al.
    Vegvari, Akos
    Levi, Michael
    Höglund, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Högberg, Marita
    Tong, Weimin
    Romero, Ivan
    Balzarini, Jan
    Vahlne, Anders
    Isolation and characterization of a small antiretroviral molecule affecting HIV-1 capsid morphology2009In: Retrovirology, ISSN 1742-4690, Vol. 6, 34- p.Article in journal (Refereed)
    Abstract [en]

    Background: Formation of an HIV-1 particle with a conical core structure is a prerequisite for the subsequent infectivity of the virus particle. We have previously described that glycineamide (G-NH2) when added to the culture medium of infected cells induces non-infectious HIV-1 particles with aberrant core structures. Results: Here we demonstrate that it is not G-NH2 itself but a metabolite thereof that displays antiviral activity. We show that conversion of G-NH2 to its antiviral metabolite is catalyzed by an enzyme present in bovine and porcine but surprisingly not in human serum. Structure determination by NMR suggested that the active G-NH2 metabolite was alpha-hydroxy-glycineamide (alpha-HGA). Chemically synthesized alpha-HGA inhibited HIV-1 replication to the same degree as G-NH2, unlike a number of other synthesized analogues of G-NH2 which had no effect on HIV-1 replication. Comparisons by capillary electrophoresis and HPLC of the metabolite with the chemically synthesized alpha-HGA further confirmed that the antiviral G-NH2-metabolite indeed was alpha-HGA. Conclusion: alpha-HGA has an unusually simple structure and a novel mechanism of antiviral action. Thus, alpha-HGA could be a lead for new antiviral substances belonging to a new class of anti-HIV drugs, i.e. capsid assembly inhibitors.

  • 34.
    Abdurakhmanov, Eldar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Discovery and evaluation of direct acting antivirals against hepatitis C virus2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Until recently, the standard therapy for hepatitis C treatment has been interferon and ribavirin. Such treatment has only 50% efficacy and is not well tolerated. The emergence of new drugs has increased the treatment efficacy to 90%. Despite such an achievement, the success is limited since the virus mutates rapidly, causing the emergence of drug resistant forms. In addition, most new drugs were developed to treat genotype 1 infections. Thus, development of new potent antivirals is needed and drug discovery against hepatitis C is continued.

    In this thesis, a FRET-based protease assay was used to evaluate new pyrazinone based NS3 protease inhibitors that are structurally different to the newly approved and currently developing drugs. Several compounds in this series showed good potencies in the nanomolar range against NS3 proteases from genotype 1, 3, and the drug resistance variant R155K. We assume that these compounds can be further developed into drug candidates that possess activity against above mentioned enzyme variants.

    By using SPR technology, we analyzed interaction mechanisms and characteristics of allosteric inhibitors targeting NS5B polymerases from genotypes 1 and 3. The compounds exhibited different binding mechanisms and displayed a low affinity against NS5B from genotype 3.

    In order to evaluate the activity and inhibitors of the NS5B polymerase, we established an SPR based assay, which enables the monitoring of polymerization and its inhibition in real time. This assay can readily be implemented for the discovery of inhibitors targeting HCV.

    An SPR based fragment screening approach has also been established. A screen of a fragment library has been performed in order to identify novel scaffolds that can be used as a starting point for development of new allosteric inhibitors against NS5B polymerase. Selected fragments will be further elaborated to generate a new potent allosteric drug candidate.

    Alternative approaches have successfully been developed and implemented to the discovery of potential lead compounds targeting two important HCV drug targets.

  • 35. Abdurakhmanov, Eldar
    et al.
    Danielson, Helena
    A time-resolved surface plasmon resonance based hepatitis C virus NS5B polymerase assay and its application for drug discoveryManuscript (preprint) (Other academic)
  • 36.
    Abdurakhmanov, Eldar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Biochemistry.
    Solbak, Sara
    Danielson, Helena
    Characterization of allosteric inhibitors of hepatitis C virus polymerase – a genotype comparative studyManuscript (preprint) (Other academic)
  • 37.
    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, 117-124 p.Article 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.

  • 38. 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, 35-38 p.Article in journal (Refereed)
  • 39.
    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)
  • 40.
    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.

  • 41.
    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, 623-634 p.Article, 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.

  • 42.
    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, 126-137 p.Article 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.

  • 43.
    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, 5407-5412 p.Article 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).

  • 44.
    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)
  • 45.
    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, 23518-23528 p.Article 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.

  • 46.
    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, 3991-3995 p.Article 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.

  • 47.
    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, 1452-1452 p.Article in journal (Other academic)
  • 48. 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, 3991-3995 p., 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.

  • 49. 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, 327-335 p.Article 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.

  • 50.
    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, 1202-1210 p.Article 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.

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