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  • 12851.
    Åbrink, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. MOLECULAR IMMUNOLOGY, LARS HELLMAN.
    Larsson, E
    Gobl, A
    Hellman, L
    Expression of lactoferrin in the kidney; implications for innate immunity and iron metabolism.2000In: Kidney International, Vol. 57, p. 2004-2010Article in journal (Refereed)
  • 12852.
    Åbrink, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. MOLECULAR IMMUNOLOGY, LARS HELLMAN.
    Larsson, E
    Hellman, L
    Demethylation of ERV3, an endogenous retrovirus regulating the krüppel-related zinc finger gene H-plk, in several human cell lines arrested during early monocyte development.1998In: DNA and Cell Biol., Vol. 17, p. 27-37Article in journal (Refereed)
  • 12853.
    Åbrink, M
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. MOLECULAR IMMUNOLOGY, LARS HELLMAN.
    Ortiz, JA
    Mark, C
    Sanchez, C
    Looman, C
    Hellman, L
    Chambon, P
    Losson, R
    Conserved interaction between distinct Kruppel-associated box domains and the transcriptional intermediary factor 1 beta2001In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, ISSN 0027-8424, Vol. 98, no 4, p. 1422-1426Article in journal (Refereed)
    Abstract [en]

    The Kruppel-associated box (KRAB) domain, originally identified as a 75-aa sequence present in numerous Kruppel-type zinc-finger proteins, is a potent DNA-binding-dependent transcriptional repression domain that is believed to function through interaction

  • 12854. Åbrink, Magnus
    et al.
    Ortiz, J.A.
    Mark, Charlotta
    Sanchez, C.
    Looman, Camilla
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hellman, Lars
    Chambon, P.
    Losson, R.
    Conserved interaction between distinct Krüppel-associated box domains and the transcriptional intermediary factor 1 beta2001In: PNAS, Vol. 98, p. 1422-1426Article in journal (Refereed)
  • 12855. Åbrink, Magnus
    et al.
    Ortiz, José A.
    Mark, Charlotta
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Sanchez, Cecilia
    Looman, Camilla
    Hellman, Lars
    Chambon, Pierre
    Losson, Régine
    Conserved Interaction Between Distinct Krüppel-associated box Domains and the Transcriptional Intermediary factor 1β2001In: Procl. Natl. Acad. Sci. USA, Vol. 98, no 4, p. 1422-1426Article in journal (Refereed)
  • 12856.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Pollinators, herbivores, and the evolution of floral traits2019In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 364, no 6436, p. 122-123Article in journal (Other academic)
  • 12857.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Solbreck, Christer
    Spatio-temporal variation in fruit production and seed predation in a perennial herb influenced by habitat quality and population size2008In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 96, no 2, p. 334-345Article in journal (Refereed)
    Abstract [en]

    1.  In patchily distributed plant species, seed production is likely to be influenced both by local abiotic factors affecting plant size and conditions for fruit maturation, and by population characteristics affecting the intensity of interactions with mutualists and antagonists. However, the relative importance of these effects is poorly known.

    2. We used multiple regression and path models to examine the importance of abiotic factors (sun exposure, soil depth) and population characteristics (size, density and connectivity) for variation in flower and fruit production and intensity of seed predation among 39 populations of the long-lived herb Vincetoxicum hirundinaria in three consecutive years. In addition, we manipulated water availability in a field experiment and recorded short-term and long-term effects on fruit output, and conducted a supplemental hand-pollination experiment.

    3.  Flower production varied little, while fruit initiation, fruit abortion and fruit predation varied considerably among years. Sun exposure and soil depth affected fruit production per plant indirectly and positively through their effects on flower number. Population density affected fruit production negatively through its effect on flower number. Both fruit initiation and the proportion of fruits attacked by the tephritid fly Euphranta connexa were related positively to population size.

    4.  The number of full-size fruits per plant was related positively to sun exposure and population size in two years each, and related negatively to population density in one year. However, because of seed predation, the number of intact mature fruits was related significantly to population characteristics in only one of three years.

    5.  The field experiments showed that both shortage of water and insufficient pollination may limit fruit set in V. hirundinaria.

    6.  Synthesis. These results demonstrate that the relative importance of local abiotic conditions and population characteristics may vary considerably along the chain of events from flower formation to intact fruit, and also among years. They further show that, at least in species with a naturally patchy distribution, connectivity may be relatively unimportant for variation in reproductive output compared to effects of habitat quality, population size and density.

     

  • 12858.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Fortunel, Claire
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Ecological Botany.
    Ehrlén, Johan
    Selection on floral display in insect-pollinated Primula farinosa: Effects of vegetation height and litter accumulation2006In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 150, no 2, p. 225-232Article in journal (Refereed)
    Abstract [en]

    Grazing reduces litter thickness and vegetation height and may thereby indirectly affect reproductive success and selection on floral characters in plants with prostrate growth. Reductions in litter thickness and vegetation height should influence both the resource status of plants with leaves positioned close to the ground and the significance of inflorescence height for interactions with pollinators and seed predators. We experimentally examined how simulated grazing of surrounding vegetation affected pollen limitation, fruit predation and fecundity of short-scaped and long-scaped Primula farinosa, which differ markedly in floral display and therefore in expected attractiveness to pollinators. Litter removal and pruning of surrounding vegetation increased fruit and seed production per plant in the year of the treatment and the probability of flowering in the following year. Pollen limitation of fruit and seed production was stronger in the short-scaped morph than in the long-scaped morph, but was not significantly affected by litter removal and simulated grazing of surrounding vegetation. Supplemental hand-pollination reduced seed size in the year of the treatment and flowering probability in the second year, and these effects did not differ among scape morphs or grazing treatments. The results suggest that grazing indirectly favours seed production in P. farinosa, mainly because it increases the resource status of plants that escape damage. Contrary to expectation, there was no strong evidence that litter accumulation and tall vegetation increase the severity of pollen limitation or reduce the relative performance of the short-scaped morph.

  • 12859.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Hellström, Frida
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Toräng, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ehrlén, Johan
    Stockholm Univ, Dept Ecol Environm & Plant Sci, SE-10691 Stockholm, Sweden.
    Mutualists and antagonists drive among-population variation in selection and evolution of floral display in a perennial herb2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 45, p. 18202-18207Article in journal (Refereed)
    Abstract [en]

    Spatial variation in the direction of selection drives the evolution of adaptive differentiation. However, few experimental studies have examined the relative importance of different environmental factors for variation in selection and evolutionary trajectories in natural populations. Here, we combine 8 y of observational data and field experiments to assess the relative importance of mutualistic and antagonistic interactions for spatial variation in selection and short-term evolution of a genetically based floral display dimorphism in the short-lived perennial herb Primula farinosa. Natural populations of this species include two floral morphs: long-scaped plants that present their flowers well above the ground and short-scaped plants with flowers positioned close to the ground. The direction and magnitude of selection on scape morph varied among populations, and so did the frequency of the short morph (median 19%, range 0–100%; n = 69 populations). A field experiment replicated at four sites demonstrated that variation in the strength of interactions with grazers and pollinators were responsible for among-population differences in relative fitness of the two morphs. Selection exerted by grazers favored the short-scaped morph, whereas pollinator-mediated selection favored the long-scaped morph. Moreover, variation in selection among natural populations was associated with differences in morph frequency change, and the experimental removal of grazers at nine sites significantly reduced the frequency of the short-scaped morph over 8 y. The results demonstrate that spatial variation in intensity of grazing and pollination produces a selection mosaic, and that changes in biotic interactions can trigger rapid genetic changes in natural plant populations.

  • 12860.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Oakley, C. G.
    McKay, J. K.
    Lovell, J. T.
    Schemske, D. W.
    Genetic mapping of adaptation reveals fitness trade-offs in Arabidopsis thaliana2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 52, p. 21077-21087Article in journal (Refereed)
    Abstract [en]

    Organisms inhabiting different environments are often locally adapted, and yet despite a considerable body of theory, the genetic basis of local adaptation is poorly understood. Unanswered questions include the number and effect sizes of adaptive loci, whether locally favored loci reduce fitness elsewhere (i.e., fitness tradeoffs), and whether a lack of genetic variation limits adaptation. To address these questions, we mapped quantitative trait loci (QTL) for total fitness in 398 recombinant inbred lines derived from a cross between locally adapted populations of the highly selfing plant Arabidopsis thaliana from Sweden and Italy and grown for 3 consecutive years at the parental sites (>40,000 plants monitored). We show that local adaptation is controlled by relatively few genomic regions of small to modest effect. A third of the 15 fitness QTL we detected showed evidence of tradeoffs, which contrasts with the minimal evidence for fitness tradeoffs found in previous studies. This difference may reflect the power of our multiyear study to distinguish conditionally neutral QTL from those that reflect fitness tradeoffs. In Sweden, but not in Italy, the local genotype underlying fitness QTL was often maladaptive, suggesting that adaptation there is constrained by a lack of adaptive genetic variation, attributable perhaps to genetic bottlenecks during postglacial colonization of Scandinavia or to recent changes in selection regime caused by climate change. Our results suggest that adaptation to markedly different environments can be achieved through changes in relatively few genomic regions, that fitness tradeoffs are common, and that lack of genetic variation can limit adaptation.

  • 12861.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Oakley, Christopher G.
    Michigan State Univ, Dept Plant Biol, E Lansing, MI 48824 USA. WWF Norway, Postboks 6784, N-0130 Oslo, Norway..
    Lundemo, Sverre
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Schemske, Douglas W.
    Michigan State Univ, Dept Plant Biol, E Lansing, MI 48824 USA.;Michigan State Univ, WK Kellogg Biol Stn, E Lansing, MI 48824 USA..
    Adaptive divergence in flowering time among natural populations of Arabidopsis thaliana: Estimates of selection and QTL mapping2017In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 71, no 3, p. 550-564Article in journal (Refereed)
    Abstract [en]

    To identify the ecological and genetic mechanisms of local adaptation requires estimating selection on traits, identifying their genetic basis, and evaluating whether divergence in adaptive traits is due to conditional neutrality or genetic trade-offs. To this end, we conducted field experiments for three years using recombinant inbred lines (RILs) derived from two ecotypes of Arabidopsis thaliana (Italy, Sweden), and at each parental site examined selection on flowering time and mapped quantitative trait loci (QTL). There was strong selection for early flowering in Italy, but weak selection in Sweden. Eleven distinct flowering time QTL were detected, and for each the Italian genotype caused earlier flowering. Twenty-seven candidate genes were identified, two of which (FLC and VIN3) appear under major flowering time QTL in Italy. Seven of eight QTL in Italy with narrow credible intervals colocalized with previously reported fitness QTL, in comparison to three of four in Sweden. The results demonstrate that the magnitude of selection on flowering time differs strikingly between our study populations, that the genetic basis of flowering time variation is multigenic with some QTL of large effect, and suggest that divergence in flowering time between ecotypes is due mainly to conditional neutrality.

  • 12862.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Schemske, Douglas W.
    Deceit pollination in Begonia2000In: Monteverde: ecology and conservation of a tropical cloud forest, Oxford University Press, 2000, p. 279-281Chapter in book (Refereed)
  • 12863.
    Ågren, Jon
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Schemske, Douglas W.
    Reciprocal transplants demonstrate strong adaptive differentiation of the model organism Arabidopsis thaliana in its native range2012In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 194, no 4, p. 1112-1122Article in journal (Refereed)
    Abstract [en]

    To quantify adaptive differentiation in the model plant Arabidopsis thaliana, we conducted reciprocal transplant experiments for five years between two European populations, one near the northern edge of the native range (Sweden) and one near the southern edge (Italy). We planted seeds (years 13) and seedlings (years 45), and estimated fitness as the number of fruits produced per seed or seedling planted. In eight of the 10 possible site x year comparisons, the fitness of the local population was significantly higher than that of the nonlocal population (3.122.2 times higher at the southern site, and 1.73.6 times higher at the northern site); in the remaining two comparisons no significant difference was recorded. At both sites, the local genotype had higher survival than the nonlocal genotype, and at the Italian site, the local genotype also had higher fecundity. Across years, the relative survival of the Italian genotype at the northern site decreased with decreasing winter soil temperature. The results provide evidence of strong adaptive differentiation between natural populations of A similar to thaliana and indicate that differences in tolerance to freezing contributed to fitness variation at the northern site. In ongoing work, we explore the functional and genetic basis of this adaptive differentiation.

  • 12864.
    Ågren, Josefin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Biology.
    Structural and Functional Studies of Giant Proteins in Lactobacillus kunkeei2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lactobacillus kunkeei is one of the most abundant bacteria within the honey crop of the honey bee. Genome sequencing of L. kunkeei isolated from honey bees all over the world showed several genes unique for L. kunkeei. Among these orphan genes, an array of four to five highly conserved genes coding for giant extracellular proteins were found. Cryogenic electron microscopy imaging of a giant-protein preparation from L. kunkeei A00901 showed an overall structure similar to a long string with a knot at the end. Further analysis showed high similarity between the different giants at the N-terminus, and secondary structure predictions showed that the same region was rich in β-sheets.  These results, combined with the knowledge of other large extracellular proteins, led to the hypothesis that the “knot” domain is located at the N-terminus and that these proteins are used by the cell to latch on to the intestine lining or other cells in the honey crop.

    In this study, predictions were made to locate the N-terminal domains of two of these giant proteins. Four different constructs were made for each protein, where three constructs were designed for expression and purification of the N-terminal domain with different end-positions, and one construct was for a predicted β-solenoid domain located downstream from the N-terminal domain. The protein constructs were recombinantly produced in E. coli, and three of the N-terminal constructs from both proteins were purified. Thermal stability was tested using nano differential scanning fluorimetry (nanoDSF), Thermofluor, and circular dichroism (CD), which all showed characteristic melting curves at low melting temperatures, ranging from 33 °C to 44 °C, for all three constructs. During CD measurements, all three constructs showed refolding after thermal denaturation and a higher abundance of antiparallel β-sheets over α-helices. Looking at the protein structure, small angle X-ray scattering data indicated that all three proteins formed elongated structures. These results indicate that a folded domain has been found for both proteins. Although, further analysis will be required to determine the boundaries of the N-terminal domains, and to elucidate if these domains have anything to do with ligand binding and the L. kunkeei ability to latch onto the honey crop.

    The full text will be freely available from 2022-08-25 16:25
  • 12865.
    Ågren, L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology.
    Hallberg, E
    Flagellar sensilla of bumble bee males (Hymenoptera, Apidae, Bombus)1996In: APIDOLOGIE, ISSN 0044-8435, Vol. 27, no 6, p. 433-444Article in journal (Refereed)
    Abstract [en]

    The flagellar sensillar distribution in males of 12 species of bumble bees, including five species with large-eyed males, did not show any conspicuous species-specific or behavior-related pattern. The sensillar types were morphologically similar to those

  • 12866.
    Ågren, Lennart
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology.
    Hallberg, Eric
    Flagellar sensilla of bumble bee males (Hymenoptera, Apidae, Bombus).1996In: Apidologie, Vol. 27, p. 433-444Article in journal (Refereed)
  • 12867.
    Åhlin, Mikaela
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre.
    Mapping the binding site of the Hof1p SH3 domain in the Bnr1p FH1 domain2014Report (Other academic)
    Abstract [en]

    The unusual syndrome Wiskott-Aldrich Syndrome has been found to be linked to a mutation in a gene expressing the Wiskott-Aldrich Syndrome protein (WASp). Due to the conservation of certain mechanisms and the homologous proteins from lower to higher eukaryotes, yeast has been used to study the molecular mechanisms that underlie diseases in humans. The yeast WASp homologue, Las17p (Local Anaexthetic Sentivie 17) and the yeast homologye Vrpp of its (i.e. human WASp) partner protein known as WIP (WASp-interacting protein), have been studied with the intention to investigate the phenotypes that arise in cells deficient in Vrp1p. A protein-protein interaction is believed to occur in the absence of Vrp1p, the interaction between the SH3 domain of the yeast F-Bar protein Hof1p and the FH1 domain of the yeast formin protein Bnr1p. This interaction is thought to have pathological effects, such as inhibition of cell proliferation and other phenotypes.

    This study has been conducted in an attempt to map the binding site of Hof1p SH3 domain in the Bnr1p FH1 domain more specifically, based on previous studies suggesting that Fragment 1(755-905) of Bnr1p Full Interacting Fragment(755-1375), including the proline- rich FH1 domain, interacts with Hof1p SH3 domain in cells deficient in Vrp1p. Both Hof1p and Bnr1p are involved in the cytokinesis stagemof the yeast cell cycle. The hypothesis implies that the excessive interaction of Hof1p SH3 domain and Bnr1p FH1 domain may interrupt the cytokinesis, which thereby can lead to the growth of defects.

    There was no finding of binding site within the Bnr1p FH1 domain for the Hof1p SH3 domain during this study. This can be due to various reason as explained later. Even though, this study has cast some doubts on previously conducted studies.

  • 12868.
    Åhlin, Mikaela
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research.
    Role of MKP-2 in crosstalk between MAPK pathways2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abnormalities in Mitogen Activated Protein Kinase (MAPK) signalling may affect the cells essential processes and influence the cell in acquiring traits to favour tumorigenic transformation and the progression of cancer. Deregulation of the MAPK pathways and uncontrolled crosstalk occurring in cancers may be caused by deregulation by MAP-kinase phosphatases (MKPs) that negatively regulates MAPKs by dephosphorylation. In this study, we were interested in the role of MKP-2 in MAPK-signalling pathways. MKP-2 is known to specifically dephosphorylate the MAP kinases Erk1/2, p38 and JNK. In this study, I was to elucidate key events leading to MKP-2 expression and the role of MKP-2 in regulating and balancing MAPK signaling. Also, I was to analyse the possible involvement of p53 in the deregulation of the MAPK pathways and its correlation with MKP-2 expression. In this report, I suggest a model where the Erk1/2 pathway in conjugation with p53 promote MKP-2 expression. I have also discovered a crosstalk between two different MAPK pathways, i.e between Erk1/2 and Erk5.

  • 12869.
    Åkerberg, Helena
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Fällmar, Helena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Sjödin, Paula
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Boukharta, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Gutierrez-de-Teran, Hugo
    Lundell, Ingrid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Mohell, Nina
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Larhammar, Dan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Mutagenesis of human neuropeptide Y/peptide YY receptor Y2 reveals additional differences to Y1 in interactions with highly conserved ligand positions2010In: Regulatory Peptides, ISSN 0167-0115, E-ISSN 1873-1686, Vol. 163, no 1-3, p. 120-129Article in journal (Refereed)
    Abstract [en]

    Neuropeptide Y (NPY) and peptide YY (PYY) share similar to 70% of their 36 amino acids and bind to the same three human receptor subtypes, Y1, Y2 and Y5, even though these receptors only share similar to 30% sequence identity Based on our previous investigation of human Y1 we describe here a mutagenesis study of three corresponding positions in human Y2, i e Tyr(2 64), Val(6 58) and Tyr(7 31) Pharmacological characterization was performed with the four peptide agonists PYY, NPY, PYY(3-36) and NPY(13-36) as well as the non-peptide antagonist BIIE0246 Results from mutants where Tyr(2 64) has been substituted by Ala suggest that Tyr(2 64) is involved in the interaction with all investigated ligands whereas position Tyr(7 31) seems to be more important for interaction with the truncated peptide PYY(3-36) than with intact NPY Surprisingly, substitution of Tyr(7 31) with His, the corresponding residue in Y1, resulted in total loss of binding of iodinated porcine PYY The third position. Val(6 58), did not influence binding of any of the ligands. These findings differ from those obtained for Y1 where Ala substitution resulted in lost or changed binding for each of the three positions. Although Tyr(2 64) and Tyr(7 31) in Y2 are involved in ligand binding, their interactions with the peptide ligands seem to be different from the corresponding positions in Y1 This suggests that the receptor-ligand interactions have changed during evolution after Y1 and Y2 arose from a common ancestral receptor.

  • 12870.
    Åkerbladh, Linda
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Lu, Lu
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Konda, Konda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Cao, Sha
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Vocat, Anthony
    Maes, Louis
    Cole, Stewart T.
    Hughes, Diarmaid
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Brandt, Peter
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Karlén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Mowbray, Sherry
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Synthesis and in vitro biological evaluation of quinolinyl pyrimidines targeting type II NADH-dehydrogenase (NDH-2)In: Article in journal (Other academic)
  • 12871.
    Åkerlund, T., Gullbrand, B., and Nordström, K.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. MICROBIOLOGY.
    Effect of the Min system on nucleoid segregation in Escherichia coli2002In: Microbiology, Vol. 148, p. 3213-3222Article in journal (Refereed)
  • 12872.
    Åkerlund, Thomas, Gullbrand, Björn, and Nordström, Kurt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Effects of the Min system on nucleoid segregation in Escherichia coli.2002In: Microbioology, Vol. 148, p. 3213-3222Article in journal (Refereed)
  • 12873.
    Åkerman Fulford, Emma
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre.
    Organic carbon getting buried deep: A study on a subtropical reservoir and comparisonwith a chain of reservoirs.2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Anthropogenic emissions of greenhouse gases are widely known to have damaging effects on the world’s environment. In the search for green energy, recent studies propose that hydropower, which is considered a renewable source of energy, contribute significantly to the emissions of carbon dioxide and in particular methane gas to the atmosphere. Hydropower dams can globally act as an important carbon source, however they can bury substantial amounts of carbon and simultaneously act as net carbon sinks. The main objective of this study is to determine, with high spatial resolution, OC burial in a tropical reservoir, Camargos, Brazil, and compare data with two reservoirs downstream to see if there is any effect of multiple damming. This master’s thesis included field studies in terms of sub-bottom profiling and sediment coring. This was followed by data analysis and mapping of seismic survey data as well as lab work including organic carbon content analysis, C:N ratio and particle size calculations in order to estimate sediment characteristics. The results propose that there is significant burial of organic carbon in Camargos reservoir, of 57.7 g C m-2 yr-1 and 121.3 g C m-2 yr-1 by sub-bottom data and individual coring respectively and evidently, reservoirs further upstream tend to accumulate more sediment and have a higher rate of OC burial. More precisely, the sub-bottom data indicate a steady decrease in OC burial rates of approximately 20%, per dam following the cascade of reservoirs downstream. However, in order to rely on hydropower as a sustainable renewable source of energy to meet the demands of a world wide growing population and economy it is essential to continue studying this topic to fully understand all aspects of the carbon processes within these systems and whether they function as substantial net sinks or sources.

    The full text will be freely available from 2020-12-01 10:06
  • 12874.
    Ålander, Marléne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre.
    Uppstart av en bioreaktor för sidoströmshydrolys vid ett reningsverk: och dess inverkan på biologisk kväve- och fosforavskiljning2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 12875.
    Ålund, Murielle
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Gametes and speciation: from prezygotic to postzygotic isolation2012Report (Other academic)
    Abstract [en]

    Speciation lies at the heart of evolutionary biology and researchers have been trying to understand the mechanisms leading to the evolution of reproductive isolation since over 250 years. Premating barriers (i.e. barriers preventing heterospecific individuals to mate with each other) and extrinsic postzygotic isolation (i.e. environmental factors affecting the fitness of hybrid individuals) have been studied in many taxa. However, little is known about what is happening at the gametic level, both before heterospecific fertilization (i.e. postmating prezygotic or gametic isolation) and in hybrid individuals (i.e. intrinsic postzygotic incompatibilities). In this essay, I will give an overview of the role gametes play in the evolution of reproductive isolation. I conclude that gametes and reproductive proteins evolve quickly, under strong influence of sexual and sexually antagonistic selection. Gametes are very diverse between species and sperm competition and female cryptic choice can lead to higher fertilization success of sperm from conspecific males. In the hybrid offspring, spermatogenesis can be easily disturbed by small differences in gene expression and this leads to a greater number of genes causing hybrid sterility compared to hybrid inviability among taxa. Following Haldane’s rule, the heterogametic sex is the first to be affected by hybrid incompatibilities, but different mechanisms seem to cause inviability and sterility and taxa with heterogametic males or heterogametic females might be affected differently. I end this review by focusing on one particular model system for studying speciation: the Ficedula flycatchers. Much is known about the ecological factors affecting speciation and hybridization between pied and collared flycatchers and new molecular data give insights into the genetics of speciation, but the role of gametes has not been studied in this system. Studies on gamete divergence and hybrid gamete production in the flycatchers will allow us to get a better idea of the role of gametes in speciation in a wild organism with homogametic males.

  • 12876.
    Ålund, Murielle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Immler, Simone
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Rice, Amber M.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Low fertility of wild hybrid male flycatchers despite recent divergence2013In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 3, article id 20130169Article in journal (Refereed)
    Abstract [en]

    Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Oland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

  • 12877.
    Ålund, Murielle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Michigan State Univ, Dept Integrat Biol, Giltner Hall 362, E Lansing, MI 48825 USA.
    Persson Schmiterlöw, Siri
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    McFarlane, S. Eryn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. Univ Edinburgh, Inst Evolutionary Biol, Charlotte Auerbach Rd, Edinburgh EH9 3FL, Midlothian, Scotland.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Optimal sperm length for high siring success depends on forehead patch size in collared flycatchers2018In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 29, no 6, p. 1436-1443Article in journal (Refereed)
    Abstract [en]

    Dominance over rivals, sexual attractiveness, and highly efficient ejaculates are 3 important contributors of male fertilization success but theories about how primary and secondary sexual characters may co-evolve largely remain to be tested. We investigated how variation in a sexual signal (forehead patch size) and sperm morphology jointly affected siring success of 70 males in a natural population of collared flycatchers. We show that the optimal sperm length to attain high relative fertilization success depended on the size of a male's secondary sexual character. Males with small forehead patches sired more offspring in their nest when they produced long sperm and vice-versa. These results are not compatible with theories based on simple relationships between display traits and sperm "quality" but imply that the optimal fertilization strategy (and hence optimal sperm traits) differs between males even in a predominantly socially monogamous population with moderate extra-pair paternity rates. Thus, a better knowledge of the complex chain of behavioural interactions between the sexes and their gametes is needed for a complete understanding of how sexual selection operates in nature.

  • 12878.
    Ålund, Murielle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Persson-Schmitterlöw, Siri
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    McFarlane, S. Eryn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Revisiting the definition of “sperm quality”: selection on sperm length depends on a male’s attractiveness and dominance in wild collared flycatchersManuscript (preprint) (Other academic)
    Abstract [en]

    Dominance over rivals, sexual attractiveness and highly efficient ejaculates are all known to be essential for male fertilization success but the theories of how primary and secondary sexual characters may co-evolve largely remain to be tested. Here, we measure sperm morphology in 131 wild-caught collared flycatchers over a four-year period and investigate the links between male display traits, sperm characteristics and siring success among 425 offspring sired by 71 of these males. We show that the optimal sperm length to attain high relative fertilization success depends on the size of a male’s secondary sexual character. Males with small ornaments sire more offspring in their own nest when they produce long sperm and vice-versa. These results are not compatible with theories based on simple relationships between secondary sexual traits and sperm “quality” but imply that the optimal fertilization strategy (and hence optimal sperm traits) differ between males even in a predominantly socially monogamous population with moderate extra-pair copulation rates. Thus, a better knowledge of the complex chain of behavioural interactions between the sexes and their gametes is needed for a complete understanding of how sexual selection operates in nature.

  • 12879.
    Ålund, Murielle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Whittington, Emma
    Center for Reproductive Evolution, 248 Life Sciences Complex, Syracuse, NY 13244, USA.
    Backström, Niclas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Borziak, Kirill
    Center for Reproductive Evolution, 248 Life Sciences Complex, Syracuse, NY 13244, USA.
    Jones, Williams
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    McFarlane, S. Eryn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Mugal, Carina F.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Wang, Mi
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Wheatcroft, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Xu, Luohao
    University of Vienna, Austria.
    Ellegren, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Immler, Simone
    School of Biological Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
    Dorus, Steve
    Center for Reproductive Evolution, 248 Life Sciences Complex, Syracuse, NY 13244, USA.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Reproductive -omics of a wild avian speciation model unveils candidate genes for gamete interactionManuscript (preprint) (Other academic)
    Abstract [en]

    The complex nature of interspecific interactions contributing to reproductive isolation means that we still know little about their molecular basis. Male reproductive traits are notorious for their fast evolution at the phenotypic and genotypic level, and divergence in components of the ejaculate can lead to incompatibilities between closely related species. Making use of recent advances of molecular tools and the extensive knowledge on the biology and ecology of young sister species, here the pied (Ficedula hypoleuca) and collared flycatcher (F. albicollis), allows the identification of candidate phenotypes and the underlying genotypes maintaining species boundaries. Pied flycatcher females can avoid costly production of sterile hybrids when mated to collared flycatchers by cryptically favouring conspecific sperm. Here, we describe the testes transcriptome and sperm proteome of both species, confirm the complexity of avian sperm development and functions and identify several candidate genes for interactions between sperm and the female reproductive tract, using multiple independent measures of divergence between the species. We show that divergence at the transcriptional and translational levels can potentially lead to the evolution of reproductive incompatibilities despite low levels of sequence divergence, and suggest that integrating several -omics techniques with knowledge of the biology of naturally hybridizing species will greatly improve our understanding of the molecular basis of speciation in the near future. 

  • 12880.
    Ålund née Podevin, Murielle
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Sex, Sperm and Speciation: On sexual selection and fertility in hybridizing flycatchers2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sexual reproduction entails complex co-evolution between the sexes, necessary for successful fertilization, ensuring individual and population-level fitness. Interfertility is the main criterion for species definition and understanding speciation requires detailed studies of reproductive barriers. However, many studies on reproductive barriers are constrained to infer evolutionary processes from patterns. In this thesis, I focus on a hybrid zone between collared and pied flycatchers (Ficedula albicollis and hypoleuca) on the island of Öland, and a trait that is essential for fertilization: sperm. Long-term monitoring of these species, combined with recent advances in molecular tools, allow me to study how complex on-going intersexual and interspecific interactions influence reproductive isolation in this young hybrid zone. I start by exploring the links between pre- and postmating sexual selection within collared flycatchers (paper I and II). I show that secondary sexual characters and indirect mate-choice benefits are tightly linked to physiology (paper I), and that a male’s attractiveness and dominance status dictate which sperm traits are optimal, as a male’s fertilization success depends on an interaction between sperm and display traits (paper II). I then report a source of strong postzygotic isolation between recently diverged collared and pied flycatchers: impaired spermatogenesis resulting in absence of mature sperm cells in hybrid males (paper III). I show however that pied flycatcher females, who are most exposed to hybridization, can mitigate these costs through mechanisms of cryptic female choice impairing heterospecific sperm performance, allowing them to bias paternity towards pure-species offspring (paper IV). Finally, by exploring the testes transcriptomes and sperm proteomes of both species, I highlight the importance of gene and protein regulation mechanisms in facilitating phenotypic divergence between these species (paper V). Thus, my thesis reveals complex interactions between primary and secondary sexual characters in a wild bird and suggests that mechanisms of sexual selection are tightly linked to essential physiological functions. I also show that genetic incompatibilities can evolve rapidly despite low genome-wide levels of divergence but that divergence in regulatory regions and proteins potentially allows fast evolution of molecular mechanisms impairing or preventing costly heterospecific fertilization. 

    List of papers
    1. Sexual selection affects climate adaptation in collared flycatchers
    Open this publication in new window or tab >>Sexual selection affects climate adaptation in collared flycatchers
    2017 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The role of sexual selection in climate adaptation is debated. We tested whether sexual selection has the potential to speed up adaptation to thermal conditions in a natural population of collared flycatchers. Based on a three-year cross-fostering experiment, we found that the size of a sexually selected trait predicted offspring metabolic rate: male collared flycatchers with large forehead patches sired offspring with low metabolic rate regardless of the ambient temperature. Thus, there was a stable significant relationship between forehead patch size of genetic fathers and offspring metabolic rate. Nestlings with high metabolic rate experienced a survival advantage when growing under warm temperatures, while the opposite was true in cold environments. Our study shows that females can modulate their offspring’s physiology through mate choice, and that sexual selection can thus affect climate adaptation.

    Keywords
    sexual selection, climate adaptation, resting metabolic rate, Ficedula flycatcher, secondary sexual character, physiology
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-322788 (URN)
    Available from: 2017-07-30 Created: 2017-07-30 Last updated: 2017-07-30
    2. Revisiting the definition of “sperm quality”: selection on sperm length depends on a male’s attractiveness and dominance in wild collared flycatchers
    Open this publication in new window or tab >>Revisiting the definition of “sperm quality”: selection on sperm length depends on a male’s attractiveness and dominance in wild collared flycatchers
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Dominance over rivals, sexual attractiveness and highly efficient ejaculates are all known to be essential for male fertilization success but the theories of how primary and secondary sexual characters may co-evolve largely remain to be tested. Here, we measure sperm morphology in 131 wild-caught collared flycatchers over a four-year period and investigate the links between male display traits, sperm characteristics and siring success among 425 offspring sired by 71 of these males. We show that the optimal sperm length to attain high relative fertilization success depends on the size of a male’s secondary sexual character. Males with small ornaments sire more offspring in their own nest when they produce long sperm and vice-versa. These results are not compatible with theories based on simple relationships between secondary sexual traits and sperm “quality” but imply that the optimal fertilization strategy (and hence optimal sperm traits) differ between males even in a predominantly socially monogamous population with moderate extra-pair copulation rates. Thus, a better knowledge of the complex chain of behavioural interactions between the sexes and their gametes is needed for a complete understanding of how sexual selection operates in nature.

    Keywords
    sperm morphology, secondary sexual character, mating strategy, fertilization success, Ficedula flycatcher, extra-pair copulation
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-326808 (URN)
    Available from: 2017-07-30 Created: 2017-07-30 Last updated: 2017-07-30
    3. Low fertility of wild hybrid male flycatchers despite recent divergence
    Open this publication in new window or tab >>Low fertility of wild hybrid male flycatchers despite recent divergence
    2013 (English)In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, no 3, article id 20130169Article in journal (Refereed) Published
    Abstract [en]

    Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Oland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

    Keywords
    hybrid, sterility-infertility, flycatcher, sperm, postzygotic incompatibility
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-202341 (URN)10.1098/rsbl.2013.0169 (DOI)000318762300035 ()
    Available from: 2013-06-24 Created: 2013-06-24 Last updated: 2017-12-06Bibliographically approved
    4. Females discriminate against heterospecific sperm in a natural hybrid zone
    Open this publication in new window or tab >>Females discriminate against heterospecific sperm in a natural hybrid zone
    Show others...
    2016 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 70, no 8, p. 1844-1855Article in journal (Refereed) Published
    Abstract [en]

    When hybridization is maladaptive, species-specific mate preferences are selectively favored, but low mate availability may constrain species-assortative pairing. Females paired to heterospecifics may then benefit by copulating with multiple males and subsequently favoring sperm of conspecifics. Whether such mechanisms for biasing paternity toward conspecifics act as important reproductive barriers in socially monogamous vertebrate species remains to be determined. We use a combination of long-term breeding records from a natural hybrid zone between collared and pied flycatchers (Ficedula albicollis and F. hypoleuca), and an in vitro experiment comparing conspecific and heterospecific sperm performance in female reproductive tract fluid, to evaluate the potential significance of female cryptic choice. We show that the females most at risk of hybridizing (pied flycatchers) frequently copulate with multiple males and are able to inhibit heterospecific sperm performance. The negative effect on heterospecific sperm performance was strongest in pied flycatcher females that were most likely to have been previously exposed to collared flycatcher sperm. We thus demonstrate that a reproductive barrier acts after copulation but before fertilization in a socially monogamous vertebrate. While the evolutionary history of this barrier is unknown, our results imply that there is opportunity for it to be accentuated via a reinforcement-like process.

    Keywords
    Cryptic female choice, hybrid zones, postcopulatory prezygotic barriers, reinforcement, speciation, sexual selection
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-303102 (URN)10.1111/evo.12986 (DOI)000381205700013 ()
    Funder
    Swedish Research Council, 621-2012-3722The Royal Swedish Academy of Sciences
    Available from: 2016-10-05 Created: 2016-09-15 Last updated: 2018-08-10Bibliographically approved
    5. Reproductive -omics of a wild avian speciation model unveils candidate genes for gamete interaction
    Open this publication in new window or tab >>Reproductive -omics of a wild avian speciation model unveils candidate genes for gamete interaction
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The complex nature of interspecific interactions contributing to reproductive isolation means that we still know little about their molecular basis. Male reproductive traits are notorious for their fast evolution at the phenotypic and genotypic level, and divergence in components of the ejaculate can lead to incompatibilities between closely related species. Making use of recent advances of molecular tools and the extensive knowledge on the biology and ecology of young sister species, here the pied (Ficedula hypoleuca) and collared flycatcher (F. albicollis), allows the identification of candidate phenotypes and the underlying genotypes maintaining species boundaries. Pied flycatcher females can avoid costly production of sterile hybrids when mated to collared flycatchers by cryptically favouring conspecific sperm. Here, we describe the testes transcriptome and sperm proteome of both species, confirm the complexity of avian sperm development and functions and identify several candidate genes for interactions between sperm and the female reproductive tract, using multiple independent measures of divergence between the species. We show that divergence at the transcriptional and translational levels can potentially lead to the evolution of reproductive incompatibilities despite low levels of sequence divergence, and suggest that integrating several -omics techniques with knowledge of the biology of naturally hybridizing species will greatly improve our understanding of the molecular basis of speciation in the near future. 

    Keywords
    Reproductive isolation, cryptic female choice, sperm, proteomics, transcriptomics, Ficedula flycatchers
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-326809 (URN)
    Available from: 2017-07-30 Created: 2017-07-30 Last updated: 2017-07-30
  • 12881.
    Ångman, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Biology Education Centre.
    Ekologikunskaper hos blivande gymnasieelever: Skillnader i kunskapen hos sökanden till högskoleförberedande- och yrkesförberedande program2014Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna undersökning är att ta reda på vilka kunskaper inom ekologi högstadieelever har med sig till gymnasiet. Eftersom de flesta gymnasieprogram innefattar kurser i naturkunskap eller biologi så vill jag ta reda på vad man som gymnasielärare kan förvänta sig att de nya eleverna har med sig i bagaget. Ekologi och hållbar utveckling genomsyrar stor del av samhällsdebatten idag och det är en del av skolan uppdrag att ge eleverna möjligheter till att ta ansvar för miljön som de kan påverka. För att en gymnasielärare ska kunna fortsätta utveckla sina elever är det av stor vikt att veta vilka grundkunskaper eleverna bär med sig. Detta för att läraren ska kunna förbereda sin undervisning på bästa sätt för att eleverna ska kunna tillgodogöra sig denna.

    Jag har utfört en enkätundersökning med 100 elever i årskurs 9 i närförort till en större stad. Hälften av deltagarna avsåg att välja ett högskoleförberedande program och hälften ett yrkesförberedande program. En hypotes är att eleverna som väljer högskoleförberedande respektive yrkesförberedande program i gymnasiet kan ha olika grad av studiemotivation vilket skulle kunna visa sig i eventuella skillnader mellan de två undersökningsgrupperna i den kvalitativa kunskapen de bär med sig.

    Resultaten visade att det inte var någon större skillnad i kvalitativa kunskaper mellan de två undersökningsgrupperna, men det fanns en signifikant skillnad i svarssäkerheten mellan grupperna. Ett annat resultat av studien var att eleverna har med sig godkända kunskapskrav i ämnet biologi men saknar en förståelse för materiens kretslopp.

  • 12882.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Calculation of Absolute Binding Free Energies for Charged Ligands and the Effects of Long-Range Electrostatic Interactions1996In: J. Comput. Chem., Vol. 17, p. 1587-Article in journal (Refereed)
  • 12883.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Comment on Transferability of Ion Models1994In: J. Phys. Chem., Vol. 98, p. 8253-Article in journal (Refereed)
  • 12884.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Computer Modeling of Chemical Reactions in Enzymes and Solution1993In: J. Biochem. Biophys. Methods, Vol. 26, p. 241-Article, book review (Other scientific)
  • 12885.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Long-Range Electrostatic Effects on Peptide Folding1999In: FEBS Lett., Vol. 457, p. 414-Article in journal (Refereed)
  • 12886.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Metalloenzymes Involving Amino Acid-Residue and Related Radicals1995In: Q. Rev. Biol., Vol. 70, p. 505-Article, book review (Other scientific)
  • 12887.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Modelling of Proton Transfer Reactions in Enzymes1997In: Computational Approaches to Biochemical Reactivity, Kluwer, Dordrecht , 1997, p. 341-Chapter in book (Refereed)
  • 12888.
    Åqvist, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    On the Sensitivity to Changes in Water-Protein Interaction Parameters1997In: Proteins, Vol. 28, p. 143-Article in journal (Refereed)
  • 12889.
    Åqvist, J. & Fothergill, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Computer Simulation of the Triosephosphate Isomerase Catalyzed Reaction1996In: J. Biol. Chem., Vol. 271, p. 10010-Article in journal (Refereed)
  • 12890.
    Åqvist, J. & Hansson, T.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Analysis of Electrostatic Potential Truncation Schemes in Simulations of Polar Solvents1998In: J. Phys. Chem., Vol. 102, p. 3837-Article in journal (Refereed)
  • 12891.
    Åqvist, J. & Hansson, T.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    On the Validity of Electrostatic Linear Response in Polar Solvents1996In: J. Phys. Chem., Vol. 100, p. 9512-Article in journal (Refereed)
  • 12892.
    Åqvist, J. & Luzhkov, V.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Ion Permeation Mechanism of the K+ Channel2000In: Nature, Vol. 404, p. 881-Article in journal (Refereed)
  • 12893.
    Åqvist, J. & Marelius, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    The Linear Interaction Energy Method for Computation of Ligand Binding Affinities2001In: Free Energy Calculations in Rational Drug Design, Kluwer, New York , 2001, p. 171-Chapter in book (Refereed)
  • 12894.
    Åqvist, J. & Marelius, J.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    The Linear Interaction Energy Method for Predicting Ligand Binding Free Energies2001In: J. Combin. Chem. High Throughput Screening, Vol. 4, p. 613-Article in journal (Refereed)
  • 12895.
    Åqvist, J. & Warshel, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Molecular Recognition in the Catalytic Action of Metalloenzymes1993In: Principles of Molecular Recognition, Chapman & Hall , 1993, p. 108-Chapter in book (Refereed)
  • 12896.
    Åqvist, J., Fothergill, M. & Warshel, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Computer Simulation of the CO2/HCO3- Interconversion Step in Human Carbonic Anhydrase I1993In: J. Am. Chem. Soc., Vol. 115, p. 631-Article in journal (Refereed)
  • 12897.
    Åqvist, J., Kolmodin, K., Florian, J. & Warshel, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Mechanistic Alternatives in Phosphate Ester Hydrolysis1999In: Chemistry & Biology, Vol. 6, p. R71-Article in journal (Refereed)
  • 12898.
    Åqvist, J., Luzhkov, V.B. & Brandsdal, B.O.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Ligand Binding Affinities from MD Simulations2002In: Acc. Chem. Res., Vol. 35, p. 358-Article in journal (Refereed)
  • 12899.
    Åqvist, J., Medina, C. & Samuelsson, J.-E.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    A New Method for Predicting Binding Affinity in Computer-Aided Drug Design1994In: Protein Eng., Vol. 7, p. 385-Article in journal (Refereed)
  • 12900.
    Åqvist, J.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Warshel, A.
    Simulation of Enzyme Reactions Using Valence Bond Force Fields and Other Hybrid Quantum/Classical Approaches1993In: Chemical ReviewsArticle in journal (Refereed)
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