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  • 1.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Ghirlanda, Stefano
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology.
    The logic of fashion cycles2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 3, e32541- p.Article in journal (Refereed)
    Abstract [en]

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

  • 2.
    Acerbi, Alberto
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution. University of Bristol, United Kingdom.
    Lampos, Vasileios
    Garnett, Philip
    Bentley, R. Alexander
    The Expression of Emotions in 20th Century Books2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 3, e59030Article in journal (Refereed)
    Abstract [en]

    We report here trends in the usage of mood words, that is, words carrying emotional content, in 20th century English language books, using the data set provided by Google that includes word frequencies in roughly 4% of all books published up to the year 2008. We find evidence for distinct historical periods of positive and negative moods, underlain by a general decrease in the use of emotion-related words through time. Finally, we show that, in books, American English has become decidedly more emotional than British English in the last half-century, as a part of a more general increase of the stylistic divergence between the two variants of English language.

  • 3. Aho, Vilma
    et al.
    Ollila, Hanna M.
    Rantanen, Ville
    Kronholm, Erkki
    Surakka, Ida
    van Leeuwen, Wessel M. A.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. University of Helsinki .
    Lehto, Maili
    Matikainen, Sampsa
    Ripatti, Samuli
    Harma, Mikko
    Sallinen, Mikael
    Salomaa, Veikko
    Jauhiainen, Matti
    Alenius, Harri
    Paunio, Tiina
    Porkka-Heiskanen, Tarja
    Partial Sleep Restriction Activates Immune Response-Related Gene Expression Pathways: Experimental and Epidemiological Studies in Humans2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 10, e77184- p.Article in journal (Refereed)
    Abstract [en]

    Epidemiological studies have shown that short or insufficient sleep is associated with increased risk for metabolic diseases and mortality. To elucidate mechanisms behind this connection, we aimed to identify genes and pathways affected by experimentally induced, partial sleep restriction and to verify their connection to insufficient sleep at population level. The experimental design simulated sleep restriction during a working week: sleep of healthy men (N = 9) was restricted to 4 h/night for five nights. The control subjects (N = 4) spent 8 h/night in bed. Leukocyte RNA expression was analyzed at baseline, after sleep restriction, and after recovery using whole genome microarrays complemented with pathway and transcription factor analysis. Expression levels of the ten most up-regulated and ten most down-regulated transcripts were correlated with subjective assessment of insufficient sleep in a population cohort (N = 472). Experimental sleep restriction altered the expression of 117 genes. Eight of the 25 most up-regulated transcripts were related to immune function. Accordingly, fifteen of the 25 most up-regulated Gene Ontology pathways were also related to immune function, including those for B cell activation, interleukin 8 production, and NF-kappa B signaling (P<0.005). Of the ten most up-regulated genes, expression of STX16 correlated negatively with self-reported insufficient sleep in a population sample, while three other genes showed tendency for positive correlation. Of the ten most down-regulated genes, TBX21 and LGR6 correlated negatively and TGFBR3 positively with insufficient sleep. Partial sleep restriction affects the regulation of signaling pathways related to the immune system. Some of these changes appear to be long-lasting and may at least partly explain how prolonged sleep restriction can contribute to inflammation-associated pathological states, such as cardiometabolic diseases.

  • 4.
    Alonso Aller, Elisa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jiddawi, Narriman S.
    Eklöf, Johan S.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Marine protected areas increase temporal stability of community structure, but not density or diversity, of tropical seagrass fish communities2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 8, e0183999Article in journal (Refereed)
    Abstract [en]

    Marine protected areas (MPAs) have been shown to increase long-term temporal stability of fish communities and enhance ecosystem resilience to anthropogenic disturbance. Yet, the potential ability of MPAs to buffer effects of environmental variability at shorter time scales remains widely unknown. In the tropics, the yearly monsoon cycle is a major natural force affecting marine organisms in tropical regions, and its timing and severity are predicted to change over the coming century, with potentially severe effects on marine organisms, ecosystems and ecosystem services. Here, we assessed the ability of MPAs to buffer effects of monsoon seasonality on seagrass-associated fish communities, using a field survey in two MPAs (no-take zones) and two unprotected (open-access) sites around Zanzibar (Tanzania). We assessed the temporal stability of fish density and community structure within and outside MPAs during three monsoon seasons in 2014-2015, and investigated several possible mechanisms that could regulate temporal stability. Our results show that MPAs did not affect fish density and diversity, but that juvenile fish densities were temporally more stable within MPAs. Second, fish community structure was more stable within MPAs for juvenile and adult fish, but not for subadult fish or the total fish community. Third, the observed effects may be due to a combination of direct and indirect (seagrass-mediated) effects of seasonality and, potentially, fluctuating fishing pressure outside MPAs. In summary, these MPAs may not have the ability to enhance fish density and diversity and to buffer effects of monsoon seasonality on the whole fish community. However, they may increase the temporal stability of certain groups, such as juvenile fish. Consequently, our results question whether MPAs play a general role in the maintenance of biodiversity and ecosystem functioning under changing environmental conditions in tropical seagrass fish communities.

  • 5.
    Andersson, Erik
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Species Richness and Assemblages in Landscapes of Different Farming Intensity - Time to Revise Conservation Strategies?2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 10, e109816- p.Article in journal (Refereed)
    Abstract [en]

    Worldwide conservation goals to protect biodiversity emphasize the need to rethink which objectives are most suitable for different landscapes. Comparing two different Swedish farming landscapes, we used survey data on birds and vascular plants to test whether landscapes with large, intensively managed farms had lower richness and diversity of the two taxa than landscapes with less intensively managed small farms, and if they differed in species composition. Landscapes with large intensively managed farms did not have lower richness than smaller low intensively managed farms. The landscape types were also similar in that they had few red listed species, normally targeted in conservation. Differences in species composition demonstrate that by having both types of agricultural landscapes regional diversity is increased, which is seldom captured in the objectives for agro-environmental policies. Thus we argue that focus on species richness or red listed species would miss the actual diversity found in the two landscape types. Biodiversity conservation, especially in production landscapes, would therefore benefit from a hierarchy of local to regional objectives with explicit targets in terms of which aspects of biodiversity to focus on.

  • 6. Andersson, Evelyn
    et al.
    Rück, Christian
    Lavebratt, Catharina
    Hedman, Erik
    Schalling, Martin
    Lindefors, Nils
    Eriksson, Elias
    Carlbring, Per
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Andersson, Gerhard
    Furmark, Tomas
    Genetic Polymorphisms in Monoamine Systems and Outcome of Cognitive Behavior Therapy for Social Anxiety Disorder2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 11, e79015Article in journal (Refereed)
    Abstract [en]

    Objective

    The role of genetics for predicting the response to cognitive behavior therapy (CBT) for social anxiety disorder (SAD) has only been studied in one previous investigation. The serotonin transporter (5-HTTLPR), the catechol-o-methyltransferase (COMT) val158met, and the tryptophan hydroxylase-2 (TPH2) G-703Tpolymorphisms are implicated in the regulation of amygdala reactivity and fear extinction and therefore might be of relevance for CBT outcome. The aim of the present study was to investigate if these three gene variants predicted response to CBT in a large sample of SAD patients.

    Method

    Participants were recruited from two separate randomized controlled CBT trials (trial 1: n = 112, trial 2: n = 202). Genotyping were performed on DNA extracted from blood or saliva samples. Effects were analyzed at follow-up (6 or 12 months after treatment) for both groups and for each group separately at post-treatment. The main outcome measure was the Liebowitz Social Anxiety Scale Self-Report.

    Results

    At long-term follow-up, there was no effect of any genotype, or gene × gene interactions, on treatment response. In the subsamples, there was time by genotype interaction effects indicating an influence of the TPH2 G-703T-polymorphism on CBT short-term response, however the direction of the effect was not consistent across trials.

    Conclusions

    None of the three gene variants, 5-HTTLPR, COMTval158met and TPH2 G-703T, was associated with long-term response to CBT for SAD.

  • 7.
    Andreasson, Claes
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Schick, Anna J.
    Pfeiffer, Susanne M.
    Sarov, Mihail
    Stewart, Francis
    Wurst, Wolfgang
    Schick, Joel A.
    Direct Cloning of Isogenic Murine DNA in Yeast and Relevance of Isogenicity for Targeting in Embryonic Stem Cells2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 9, e74207- p.Article in journal (Refereed)
    Abstract [en]

    Efficient gene targeting in embryonic stem cells requires that modifying DNA sequences are identical to those in the targeted chromosomal locus. Yet, there is a paucity of isogenic genomic clones for human cell lines and PCR amplification cannot be used in many mutation-sensitive applications. Here, we describe a novel method for the direct cloning of genomic DNA into a targeting vector, pRTVIR, using oligonucleotide-directed homologous recombination in yeast. We demonstrate the applicability of the method by constructing functional targeting vectors for mammalian genes Uhrf1 and Gfap. Whereas the isogenic targeting of the gene Uhrf1 showed a substantial increase in targeting efficiency compared to non-isogenic DNA in mouse E14 cells, E14-derived DNA performed better than the isogenic DNA in JM8 cells for both Uhrf1 and Gfap. Analysis of 70 C57BL/6-derived targeting vectors electroporated in JM8 and E14 cell lines in parallel showed a clear dependence on isogenicity for targeting, but for three genes isogenic DNA was found to be inhibitory. In summary, this study provides a straightforward methodological approach for the direct generation of isogenic gene targeting vectors.

  • 8.
    Angeler, David G.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Allen, Craig R.
    Garmestani, Ahjond S.
    Gunderson, Lance H.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Winder, Monika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Quantifying the Adaptive Cycle2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 12, e0146053Article in journal (Refereed)
    Abstract [en]

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  • 9.
    Angleman, Sara B.
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Santoni, Giola
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Pilotto, Alberto
    Fratiglioni, Laura
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Stockholm Gerontology Research Center, Karolinska Institutet.
    Welmer, Anna-Karin
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Multidimensional Prognostic Index in Association with Future Mortality and Number of Hospital Days in a Population-Based Sample of Older Adults: Results of the EU Funded MPI_AGE Project2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 7, e0133789Article in journal (Refereed)
    Abstract [en]

    Background The Multidimensional Prognostic Index (MPI) has been found to predict mortality in patients with a variety of clinical conditions. We aimed to assess the association of the MPI with future mortality and number of in-hospital days for the first time in a population-based cohort. Methods The study population consisted of 2472 persons, aged 66-99 years, from the Swedish National Study on Aging and Care in Kungsholmen, Sweden, who underwent the baseline visit 2001-4, and were followed up >10 years for in-hospital days and >12 years for mortality. The MPI was a modified version of the original and aggregated seven domains (personal and instrumental activities of daily living, cognitive function, illness severity and comorbidity, number of medications, co-habitation status, and nutritional status). The MPI score was divided into risk groups: low, medium and high. Number of in-hospital days (within 1, 3 and 10 years) and mortality data were derived from official registries. All analyses were age-stratified (sexagenarians, septuagenarians, octogenarians, nonagenarians). Results During the follow-up 1331 persons (53.8%) died. Laplace regression models, suggested that median survival in medium risk groups varied by age from 2.2-3.6 years earlier than for those in the corresponding low risk groups (p = 0.002-p<0.001), and median survival in high risk groups varied by age from 3.8-9.0 years earlier than for corresponding low risk groups (p<0.001). For nonagenarians, the median age at death was 3.8 years earlier in the high risk group than for the low risk group (p<0.001). The mean number of in-hospital days increased significantly with higher MPI risk score within 1 and 3 years for people of each age group. Conclusion For the first time, the effectiveness of MPI has been verified in a population-based cohort. Higher MPI risk scores associated with more days in hospital and with fewer years of survival, across a broad and stratified age range.

  • 10. Anstey, Kaarin J.
    et al.
    Cherbuin, Nicolas
    Herath, Pushpani M.
    Qiu, Chengxuan
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Kuller, Lewis H.
    Lopez, Oscar L.
    Wilson, Robert S.
    Fratiglioni, Laura
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    A Self-Report Risk Index to Predict Occurrence of Dementia in Three Independent Cohorts of Older Adults: The ANU-ADRI2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 1, e86141- p.Article in journal (Refereed)
    Abstract [en]

    Background and Aims: The Australian National University AD Risk Index (ANU-ADRI, http://anuadri.anu.edu.au) is a self-report risk index developed using an evidence-based medicine approach to measure risk of Alzheimer's disease (AD). We aimed to evaluate the extent to which the ANU-ADRI can predict the risk of AD in older adults and to compare the ANU-ADRI to the dementia risk index developed from the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study for middle-aged cohorts. Methods: This study included three validation cohorts, i.e., the Rush Memory and Aging Study (MAP) (n = 903, age >= 53 years), the Kungsholmen Project (KP) (n = 905, age >= 75 years), and the Cardiovascular Health Cognition Study (CVHS) (n = 2496, age >= 65 years) that were each followed for dementia. Baseline data were collected on exposure to the 15 risk factors included in the ANU-ADRI of which MAP had 10, KP had 8 and CVHS had 9. Risk scores and C-statistics were computed for individual participants for the ANU-ADRI and the CAIDE index. Results: For the ANU-ADRI using available data, the MAP study c-statistic was 0.637 (95% CI 0.596-0.678), for the KP study it was 0.740 (0.712-0.768) and for the CVHS it was 0.733 (0.691-0.776) for predicting AD. When a common set of risk and protective factors were used c-statistics were 0.689 (95% CI 0.650-0.727), 0.666 (0.628-0.704) and 0.734 (0.707-0.761) for MAP, KP and CVHS respectively. Results for CAIDE ranged from c-statistics of 0.488 (0.427-0.554) to 0.595 (0.565-0.625). Conclusion: A composite risk score derived from the ANU-ADRI weights including 8-10 risk or protective factors is a valid, self-report tool to identify those at risk of AD and dementia. The accuracy can be further improved in studies including more risk factors and younger cohorts with long-term follow-up.

  • 11. Anund, Anna
    et al.
    Fors, Carina
    Hallvig, David
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Observer rated sleepiness and real road driving: an explorative study2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 5, e64782Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to explore if observer rated sleepiness (ORS) is a feasible method for quantification of driver sleepiness in field studies. Two measures of ORS were used: (1) one for behavioural signs based on facial expression, body gestures and body movements labelled B-ORS, and (2) one based on driving performance e.g. if swerving and other indicators of impaired driving occurs, labelled D-ORS. A limited number of observers sitting in the back of an experimental vehicle on a motorway about 2 hours repeatedly 3 times per day (before lunch, after lunch, at night) observed 24 participant's sleepiness level with help of the two observer scales. At the same time the participant reported subjective sleepiness (KSS), EOG was recorded (for calculation of blink duration) and several driving measure were taken and synchronized with the reporting. Based on mixed model Anova and correlation analysis the result showed that observer ratings of sleepiness based on drivers' impaired performance and behavioural signs are sensitive to extend the general pattern of time awake, circadian phase and time of driving. The detailed analysis of the subjective sleepiness and ORS showed weak correspondence on an individual level. Only 16% of the changes in KSS were predicted by the observer. The correlation between the observer ratings based on performance (D-ORS) and behavioural signs (B-ORS) are high (r = .588), and the B-ORS shows a moderately strong association (r = .360) with blink duration. Both ORS measures show an association (r>0.45) with KSS, whereas the association with driving performance is weak. The results show that the ORS-method detects the expected general variations in sleepy driving in field studies, however, sudden changes in driver sleepiness on a detailed level as 5 minutes is usually not detected; this holds true both when taking into account driving behaviour or driver behavioural signs.

  • 12.
    Arama, Charles
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Immunology.
    Giusti, Pablo
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Immunology.
    Boström, Stephanie
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Immunology.
    Varani, Stefania
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Immunology.
    Troye Blomberg, Marita
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Immunology.
    Interethnic Differences in Antigen-Presenting Cell Activation and TLR Responses in Malian Children during Plasmodium falciparum Malaria2011In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 3, e18319- p.Article in journal (Refereed)
    Abstract [en]

    The Fulani ethnic group from West Africa is relatively better protected against Plasmodium falciparum malaria as compared to other sympatric ethnic groups, such as the Dogon. However, the mechanisms behind this lower susceptibility to malaria are largely unknown, particularly those concerning innate immunity. Antigen-presenting cells (APCs), and in particular dendritic cells (DCs) are important components of the innate and adaptive immune systems. Therefore, in this study we investigated whether APCs obtained from Fulani and Dogon children exhibited differences in terms of activation status and toll-like receptor (TLR) responses during malaria infection. Lower frequency and increased activation was observed in circulating plasmacytoid DCs and BDCA-3+ myeloid DCs of infected Fulani as compared to their uninfected counterparts. Conversely, a higher frequency and reduced activation was observed in the same DC subsets obtained from peripheral blood of P. falciparum-infected Dogon children as compared to their uninfected peers. Moreover, infected individuals of both ethnic groups exhibited higher percentages of both classical and inflammatory monocytes that were less activated as compared to their non-infected counterparts. In line with APC impairment during malaria infection, TLR4, TLR7 and TLR9 responses were strongly inhibited by P. falciparum infection in Dogon children, while no such TLR inhibition was observed in the Fulani children. Strikingly, the TLR-induced IFN-γ release was completely abolished in the Dogon undergoing infection while no difference was seen within infected and non-infected Fulani. Thus, P. falciparum infection is associated with altered activation status of important APC subsets and strongly inhibited TLR responses in peripheral blood of Dogon children. In contrast, P. falciparum induces DC activation and does not affect the innate response to specific TLR ligands in Fulani children. These findings suggest that DCs and TLR signalling may be of importance for the protective immunity against malaria observed in the Fulani.

  • 13. Araujo, Sabrina B. L.
    et al.
    Braga, Mariana Pires
    Universidade Federal do Paraná, Brazil.
    Brooks, Daniel R.
    Agosta, Salvatore J.
    Hoberg, Eric P.
    von Hartenthal, Francisco W.
    Boeger, Walter A.
    Understanding host-switching by ecological fitting2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, e0139225Article in journal (Refereed)
    Abstract [en]

    Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.

  • 14. Ardehed, Angelica
    et al.
    Johansson, Daniel
    Sundqvist, Lisa
    Schagerström, Ellen
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Zagrodzka, Zuzanna
    Kovaltchouk, Nikolaj A.
    Bergström, Lena
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rafajlovic, Marina
    Pereyra, Ricardo T.
    Johannesson, Kerstin
    Divergence within and among Seaweed Siblings (Fucus vesiculosus and F. radicans) in the Baltic Sea2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 8, e0161266Article in journal (Refereed)
    Abstract [en]

    Closely related taxa provide significant case studies for understanding evolution of new species but may simultaneously challenge species identification and definition. In the Baltic Sea, two dominant and perennial brown algae share a very recent ancestry. Fucus vesiculosus invaded this recently formed postglacial sea 8000 years ago and shortly thereafter Fucus radicans diverged from this lineage as an endemic species. In the Baltic Sea both species reproduce sexually but also recruit fully fertile new individuals by asexual fragmentation. Earlier studies have shown local differences in morphology and genetics between the two taxa in the northern and western Bothnian Sea, and around the island of Saaremaa in Estonia, but geographic patterns seemin conflict with a single origin of F. radicans. To investigate the relationship between northern and Estonian distributions, we analysed the genetic variation using 9 microsatellite loci in populations from eastern Bothnian Sea, Archipelago Sea and the Gulf of Finland. These populations are located in between earlier studied populations. However, instead of bridging the disparate genetic gap between N-W Bothnian Sea and Estonia, as expected from a simple isolation-by-distance model, the new populations substantially increased overall genetic diversity and showed to be strongly divergent from the two earlier analysed regions, showing signs of additional distinct populations. Contrasting earlier findings of increased asexual recruitment in low salinity in the Bothnian Sea, we found high levels of sexual reproduction in some of the Gulf of Finland populations that inhabit extremely low salinity. The new data generated in this study supports the earlier conclusion of two reproductively isolated but very closely related species. However, the new results also add considerable genetic and morphological complexity within species. This makes species separation at geographic scales more demanding and suggests a need for more comprehensive approaches to further disentangle the intriguing relationship and history of the Baltic Sea fucoids.

  • 15.
    Arefin, Badrul
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Kucerova, Lucie
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Krautz, Robert
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Kranenburg, Holger
    Parvin, Farjana
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Theopold, Ulrich
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Apoptosis in Hemocytes Induces a Shift in Effector Mechanisms in the Drosophila Immune System and Leads to a Pro-Inflammatory State2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 8, e0136593Article in journal (Refereed)
    Abstract [en]

    Apart from their role in cellular immunity via phagocytosis and encapsulation, Drosophila hemocytes release soluble factors such as antimicrobial peptides, and cytokines to induce humoral responses. In addition, they participate in coagulation and wounding, and in development. To assess their role during infection with entomopathogenic nematodes, we depleted plasmatocytes and crystal cells, the two classes of hemocytes present in naive larvae by expressing proapoptotic proteins in order to produce hemocyte-free (Hml-apo, originally called Hemo(less)) larvae. Surprisingly, we found that Hml-apo larvae are still resistant to nematode infections. When further elucidating the immune status of Hml-apo larvae, we observe a shift in immune effector pathways including massive lamellocyte differentiation and induction of Toll-as well as repression of imd signaling. This leads to a pro-inflammatory state, characterized by the appearance of melanotic nodules in the hemolymph and to strong developmental defects including pupal lethality and leg defects in escapers. Further analysis suggests that most of the phenotypes we observe in Hml-apo larvae are alleviated by administration of antibiotics and by changing the food source indicating that they are mediated through the microbiota. Biochemical evidence identifies nitric oxide as a key phylogenetically conserved regulator in this process. Finally we show that the nitric oxide donor L-arginine similarly modifies the response against an early stage of tumor development in fly larvae.

  • 16.
    Arnberg, Filip K.
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Uppsala University, Sweden.
    Michel, Per-Olof
    Lundin, Tom
    Posttraumatic stress in survivors 1 month to 19 years after an airliner emergency landing2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 3, e0119732Article in journal (Refereed)
    Abstract [en]

    Posttraumatic stress (PTS) is common in survivors from life-threatening events. Little is known, however, about the course of PTS after life threat in the absence of collateral stressors (e.g., bereavement, social stigma, property loss) and there is a scarcity of studies about PTS in the long term. This study assessed the short- and long-term course of PTS, and the influence of gender, education and age on the level and course of PTS, in survivors from a non-fatal airliner emergency landing caused by engine failure at an altitude of 1 km. There were 129 persons on board. A survey including the Impact of Event Scale was distributed to 106 subjects after 1 month, 4 months, 14 months, and 25 months, and to 95 subjects after 19 years (response rates 64-83%). There were initially high levels of PTS. The majority of changes in PTS occurred from 1 to 4 months after the event. There were small changes from 4 to 25 months but further decrease in PTS thereafter. Female gender was associated with higher levels of PTS whereas gender was unrelated to the slope of the short- and long-term trajectories. Higher education was related to a quicker recovery although not to initial or long-term PTS. Age was not associated with PTS. The present findings suggest that a life-threatening experience without collateral stressors may produce high levels of acute posttraumatic stress, yet with a benign prognosis. The findings further implicate that gender is unrelated to trajectories of recovery in the context of highly similar exposure and few collateral stressors.

  • 17. Asmat, Tauseef M.
    et al.
    Tenenbaum, Tobias
    Jonsson, Ann-Beth
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Schwerk, Christian
    Schroten, Horst
    Impact of Calcium Signaling during Infection of Neisseria meningitidis to Human Brain Microvascular Endothelial Cells2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 12, e114474- p.Article in journal (Refereed)
    Abstract [en]

    The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.

  • 18.
    Asplund-Samuelsson, Johannes
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Birgitta
    Stockholm University, Faculty of Science, Department of Botany.
    Larsson, John
    Stockholm University, Faculty of Science, Department of Botany.
    Prokaryotic Caspase Homologs: Phylogenetic Patterns and Functional Characteristics Reveal Considerable Diversity2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 11, e49888- p.Article in journal (Refereed)
    Abstract [en]

    Caspases accomplish initiation and execution of apoptosis, a programmed cell death process specific to metazoans. The existence of prokaryotic caspase homologs, termed metacaspases, has been known for slightly more than a decade. Despite their potential connection to the evolution of programmed cell death in eukaryotes, the phylogenetic distribution and functions of these prokaryotic metacaspase sequences are largely uncharted, while a few experiments imply involvement in programmed cell death. Aiming at providing a more detailed picture of prokaryotic caspase homologs, we applied a computational approach based on Hidden Markov Model search profiles to identify and functionally characterize putative metacaspases in bacterial and archaeal genomes. Out of the total of 1463 analyzed genomes, merely 267 (18%) were identified to contain putative metacaspases, but their taxonomic distribution included most prokaryotic phyla and a few archaea (Euryarchaeota). Metacaspases were particularly abundant in Alphaproteobacteria, Deltaproteobacteria and Cyanobacteria, which harbor many morphologically and developmentally complex organisms, and a distinct correlation was found between abundance and phenotypic complexity in Cyanobacteria. Notably, Bacillus subtilis and Escherichia coli, known to undergo genetically regulated autolysis, lacked metacaspases. Pfam domain architecture analysis combined with operon identification revealed rich and varied configurations among the metacaspase sequences. These imply roles in programmed cell death, but also e.g. in signaling, various enzymatic activities and protein modification. Together our data show a wide and scattered distribution of caspase homologs in prokaryotes with structurally and functionally diverse subgroups, and with a potentially intriguing evolutionary role. These features will help delineate future characterizations of death pathways in prokaryotes.

  • 19. Assadi, Ghazaleh
    et al.
    Vesterlund, Liselotte
    Bonfiglio, Ferdinando
    Mazzurana, Luca
    Cordeddu, Lina
    Schepis, Danika
    Mjösberg, Jenny
    Ruhrmann, Sabrina
    Fabbri, Alessia
    Vukojevic, Vladana
    Percipalle, Piergiorgio
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. New York University Abu Dhabi, United Arab Emirates.
    Salomons, Florian A.
    Laurencikiene, Jurga
    Törkvist, Leif
    Halfvarson, Jonas
    D'Amato, Mauro
    Functional Analyses of the Crohn's Disease Risk Gene LACC12016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 12, e0168276Article in journal (Refereed)
    Abstract [en]

    Background Genetic variation in the Laccase (multicopper oxidoreductase) domain-containing 1 (LACC1) gene has been shown to affect the risk of Crohn's disease, leprosy and, more recently, ulcerative colitis and juvenile idiopathic arthritis. LACC1 function appears to promote fatty-acid oxidation, with concomitant inflammasome activation, reactive oxygen species production, and anti-bacterial responses in macrophages. We sought to contribute to elucidating LACC1 biological function by extensive characterization of its expression in human tissues and cells, and through preliminary analyses of the regulatory mechanisms driving such expression. Methods We implemented Western blot, quantitative real-time PCR, immunofluorescence microscopy, and flow cytometry analyses to investigate fatty acid metabolism-immune nexus (FAMIN; the LACC1 encoded protein) expression in subcellular compartments, cell lines and relevant human tissues. Gene-set enrichment analyses were performed to initially investigate modulatory mechanisms of LACC1 expression. A small-interference RNA knockdown in vitro model system was used to study the effect of FAMIN depletion on peroxisome function. Results FAMIN expression was detected in macrophage-differentiated THP-1 cells and several human tissues, being highest in neutrophils, monocytes/macrophages, myeloid and plasmacytoid dendritic cells among peripheral blood cells. Subcellular co-localization was exclusively confined to peroxisomes, with some additional positivity for organelle endomembrane structures. LACC1 co-expression signatures were enriched for genes involved in peroxisome proliferator-activated receptors (PPAR) signaling pathways, and PPAR ligands downregulated FAMIN expression in in vitro model systems. Conclusion FAMIN is a peroxisome-associated protein with primary role(s) in macrophages and other immune cells, where its metabolic functions may be modulated by PPAR signaling events. However, the precise molecular mechanisms through which FAMIN exerts its biological effects in immune cells remain to be elucidated.

  • 20.
    Audusseau, Hélène
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kolb, Gundula
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Plant Fertilization Interacts with Life History: Variation in Stoichiometry and Performance in Nettle-Feeding Butterflies2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 5, e0124616Article in journal (Refereed)
    Abstract [en]

    Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in Aglais urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities.

  • 21.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Humans as long-distance dispersers of rural plant communities2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 5, e62763- p.Article in journal (Refereed)
    Abstract [en]

    Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for speciesthreatened by habitat destruction, but research into human-mediated dispersal is often focussed upon few and/or invasive species.Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a knownspecies pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in analternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71species (36%) are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendageswere more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted inmore dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances weremeasured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities inwhich they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might havebeen regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscapemay have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat andchanges in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role ofhumans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance andregional dispersal, and international invasion.

  • 22. Aurelius, Oskar
    et al.
    Johansson, Renzo
    Bågenholm, Viktoria
    Lundin, Daniel
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Tholander, Fredrik
    Balhuizen, Alexander
    Beck, Tobias
    Sahlin, Margareta
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Sjöberg, Britt-Marie
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Mulliez, Etienne
    Logan, Derek T.
    The Crystal Structure of Thermotoga maritima Class III Ribonucleotide Reductase Lacks a Radical Cysteine Pre-Positioned in the Active Site2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 7, e0128199Article in journal (Refereed)
    Abstract [en]

    Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides, the building blocks for DNA synthesis, and are found in all but a few organisms. RNRs use radical chemistry to catalyze the reduction reaction. Despite RNR having evolved several mechanisms for generation of different kinds of essential radicals across a large evolutionary time frame, this initial radical is normally always channelled to a strictly conserved cysteine residue directly adjacent to the substrate for initiation of substrate reduction, and this cysteine has been found in the structures of all RNRs solved to date. We present the crystal structure of an anaerobic RNR from the extreme thermophile Thermotoga maritima (tmNrdD), alone and in several complexes, including with the allosteric effector dATP and its cognate substrate CTP. In the crystal structure of the enzyme as purified, tmNrdD lacks a cysteine for radical transfer to the substrate pre-positioned in the active site. Nevertheless activity assays using anaerobic cell extracts from T. maritima demonstrate that the class III RNR is enzymatically active. Other genetic and microbiological evidence is summarized indicating that the enzyme is important for T. maritima. Mutation of either of two cysteine residues in a disordered loop far from the active site results in inactive enzyme. We discuss the possible mechanisms for radical initiation of substrate reduction given the collected evidence from the crystal structure, our activity assays and other published work. Taken together, the results suggest either that initiation of substrate reduction may involve unprecedented conformational changes in the enzyme to bring one of these cysteine residues to the expected position, or that alternative routes for initiation of the RNR reduction reaction may exist. Finally, we present a phylogenetic analysis showing that the structure of tmNrdD is representative of a new RNR subclass IIIh, present in all Thermotoga species plus a wider group of bacteria from the distantly related phyla Firmicutes, Bacteroidetes and Proteobacteria.

  • 23. Bagger-Sjöbäck, Dan
    et al.
    Strömbäck, Karin
    Hakizimana, Pierre
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Larsson, Christina
    Hultcrantz, Malou
    Papatziamos, Georgios
    Smeds, Henrik
    Danckwardt-Lillieström, Niklas
    Hellström, Sten
    Johansson, Ann
    Tideholm, Bo
    Fridberger, Anders
    A Randomised, Double Blind Trial of N-Acetylcysteine for Hearing Protection during Stapes Surgery2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 3, e0115657Article in journal (Refereed)
    Abstract [en]

    Background Otosclerosis is a disorder that impairs middle ear function, leading to conductive hearing loss. Surgical treatment results in large improvement of hearing at low sound frequencies, but high-frequency hearing often suffers. A likely reason for this is that inner ear sensory cells are damaged by surgical trauma and loud sounds generated during the operation. Animal studies have shown that antioxidants such as N-Acetylcysteine can protect the inner ear from noise, surgical trauma, and some ototoxic substances, but it is not known if this works in humans. This trial was performed to determine whether antioxidants improve surgical results at high frequencies. Methods We performed a randomized, double-blind and placebo-controlled parallel group clinical trial at three Swedish university clinics. Using block-stratified randomization, 156 adult patients undergoing stapedotomy were assigned to intravenous N-Acetylcysteine (150 mg/kg body weight) or matching placebo (1:1 ratio), starting one hour before surgery. The primary outcome was the hearing threshold at 6 and 8 kHz; secondary outcomes included the severity of tinnitus and vertigo. Findings One year after surgery, high-frequency hearing had improved 2.7 +/- 3.8 dB in the placebo group (67 patients analysed) and 2.4 +/- 3.7 dB in the treated group (72 patients; means +/- 95% confidence interval, p = 0.54; linear mixed model). Surgery improved tinnitus, but there was no significant intergroup difference. Post-operative balance disturbance was common but improved during the first year, without significant difference between groups. Four patients receiving N-Acetylcysteine experienced mild side effects such as nausea and vomiting. Conclusions N-Acetylcysteine has no effect on hearing thresholds, tinnitus, or balance disturbance after stapedotomy.

  • 24.
    Balk, Lennart
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hylland, Ketil
    Hansson, Tomas
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berntssen, Marc H. G.
    Beyer, Jonny
    Jonsson, Grete
    Melbye, Alf
    Grung, Merete
    Torstensen, Bente E.
    Borseth, Jan Fredrik
    Skarphedinsdottir, Halldora
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Klungsoyr, Jarle
    Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production2011In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 5, e19735- p.Article in journal (Refereed)
    Abstract [en]

    Background: Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills. Methods and principal findings: Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea. Conclusion: It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production.

  • 25. Banack, Sandra Anne
    et al.
    Metcalf, James S.
    Jiang, Liying
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Craighead, Derek
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Cox, Paul Alan
    Cyanobacteria Produce N-(2-Aminoethyl)Glycine, a Backbone for Peptide Nucleic Acids Which May Have Been the First Genetic Molecules for Life on Earth2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 11, e49043- p.Article in journal (Refereed)
    Abstract [en]

    Prior to the evolution of DNA-based organisms on earth over 3.5 billion years ago it is hypothesized that RNA was the primary genetic molecule. Before RNA-based organisms arose, peptide nucleic acids may have been used to transmit genetic information by the earliest forms of life on earth. We discovered that cyanobacteria produce N-(2-aminoethyl)glycine (AEG), a backbone for peptide nucleic acids. We detected AEG in axenic strains of cyanobacteria with an average concentration of 1 µg/g. We also detected AEG in environmental samples of cyanobacteria as both a free or weakly bound molecule and a tightly bound form released by acid hydrolysis, at concentrations ranging from not detected to 34 µg/g. The production of AEG by diverse taxa of cyanobacteria suggests that AEG may be a primitive feature which arose early in the evolution of life on earth

  • 26. Barbeiro, A. R.
    et al.
    Ureba, Ana
    Stockholm University, Faculty of Science, Department of Physics. Universidad de Sevilla, Spain; Instituto de Biomedicina de Sevilla, IBIS, Spain; Karolinska Institutet, Sweden.
    Baeza, J. A.
    Linares, R.
    Perucha, M.
    Jimenez-Ortega, E.
    Velazquez, S.
    Mateos, J. C.
    Leal, A.
    3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 11, e0166767Article in journal (Refereed)
    Abstract [en]

    A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measurements (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discretization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.

  • 27.
    Basile, Walter
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Salvatore, Marco
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Elofsson, Arne
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    The classification of orphans is improved by combining searches in both proteomes and genomes2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203Article in journal (Refereed)
    Abstract [en]

    The detection of genes without homologs (“orphans”) in other species is important, as it provides a glimpse on the evolutionary processes that create novel genes. However, for an unbiased view of such de novo gene creation the detection of these genes needs to be accurate. The estimation of the conservation, and in general the age determination of any gene, is dependent on two factors: (i) a method to detect homologs in a genome and (ii) a set of related genomes. Here, we set out to investigate how the detection of orphans is influenced be these factors. We show that when using multiple genomes and six-frame translations of complete genomes the number of orphans is significantly reduced, when compared with earlier studies. Given these premises we obtain a strict set of 34 orphan Saccharomyces cerevisiae genes, and show that the number of orphans in Drosophila melanogaster and Drosophila pseudoobscura can be reduced to only 30 and 17, respectively.

  • 28. Becnel, Jaime
    et al.
    Johnson, Oralee
    Luo, Jiangnan
    Stockholm University, Faculty of Science, Department of Zoology.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nichols, Charles D.
    The Serotonin 5-HT(7)Dro Receptor Is Expressed in the Brain of Drosophila, and Is Essential for Normal Courtship and Mating2011In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 6, e20800- p.Article in journal (Refereed)
    Abstract [en]

    The 5-HT(7) receptor remains one of the less well characterized serotonin receptors. Although it has been demonstrated to be involved in the regulation of mood, sleep, and circadian rhythms, as well as relaxation of vascular smooth muscles in mammals, the precise mechanisms underlying these functions remain largely unknown. The fruit fly, Drosophila melanogaster, is an attractive model organism to study neuropharmacological, molecular, and behavioral processes that are largely conserved with mammals. Drosophila express a homolog of the mammalian 5-HT(7) receptor, as well as homologs for the mammalian 5-HT(1A), and 5-HT(2), receptors. Each fly receptor couples to the same effector pathway as their mammalian counterpart and have been demonstrated to mediate similar behavioral responses. Here, we report on the expression and function of the 5-HT(7)Dro receptor in Drosophila. In the larval central nervous system, expression is detected postsynaptically in discreet cells and neuronal circuits. In the adult brain there is strong expression in all large-field R neurons that innervate the ellipsoid body, as well as in a small group of cells that cluster with the PDF-positive LNvs neurons that mediate circadian activity. Following both pharmacological and genetic approaches, we have found that 5-HT(7)Dro activity is essential for normal courtship and mating behaviors in the fly, where it appears to mediate levels of interest in both males and females. This is the first reported evidence of direct involvement of a particular serotonin receptor subtype in courtship and mating in the fly.

  • 29.
    Beltran-Pardo, Eliana
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Jonsson, K. Ingemar
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Kristianstad University, Sweden.
    Harms-Ringdahl, Mats
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Haghdoost, Siamak
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Wojcik, Andrzej
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Tolerance to Gamma Radiation in the Tardigrade Hypsibius dujardini from Embryo to Adult Correlate Inversely with Cellular Proliferation2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 7, e0133658Article in journal (Refereed)
    Abstract [en]

    Tardigrades are highly tolerant to desiccation and ionizing radiation but the mechanisms of this tolerance are not well understood. In this paper, we report studies on dose responses of adults and eggs of the tardigrade Hypsibius dujardini exposed to gamma radiation. In adults the LD50/48h for survival was estimated at similar to 4200 Gy, and doses higher than 100 Gy reduced both fertility and hatchability of laid eggs drastically. We also evaluated the effect of radiation (doses 50 Gy, 200 Gy, 500 Gy) on eggs in the early and late embryonic stage of development, and observed a reduced hatchability in the early stage, while no effect was found in the late stage of development. Survival of juveniles from irradiated eggs was highly affected by a 500 Gy dose, both in the early and the late stage. Juveniles hatched from eggs irradiated at 50 Gy and 200 Gy developed into adults and produced offspring, but their fertility was reduced compared to the controls. Finally we measured the effect of low temperature during irradiation at 4000 Gy and 4500 Gy on survival in adult tardigrades, and observed a slight delay in the expressed mortality when tardigrades were irradiated on ice. Since H. dujardini is a freshwater tardigrade with lower tolerance to desiccation compared to limno-terrestrial tardigrades, the high radiation tolerance in adults, similar to limno-terrestrial tardigrades, is unexpected and seems to challenge the idea that desiccation and radiation tolerance rely on the same molecular mechanisms. We suggest that the higher radiation tolerance in adults and late stage embryos of H. dujardini (and in other studied tardigrades) compared to early stage embryos may partly be due to limited mitotic activity, since tardigrades have a low degree of somatic cell division (eutely), and dividing cells are known to be more sensitive to radiation.

  • 30.
    Beltran-Pardo, Eliana
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Pontifical University of Javeriana.
    Jonsson, K. Ingemar
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Kristianstad University.
    Wojcik, Andrzej
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Haghdoost, Siamak
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Harms-Ringdahl, Mats
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Bermudez-Cruz, Rosa M.
    Villegas, Jaime E. Bernal
    Effects of Ionizing Radiation on Embryos of the Tardigrade Milnesium cf. tardigradum at Different Stages of Development2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 9, e72098- p.Article in journal (Refereed)
    Abstract [en]

    Tardigrades represent one of the most desiccation and radiation tolerant animals on Earth, and several studies have documented their tolerance in the adult stage. Studies on tolerance during embryological stages are rare, but differential effects of desiccation and freezing on different developmental stages have been reported, as well as dose-dependent effect of gamma irradiation on tardigrade embryos. Here, we report a study evaluating the tolerance of eggs from the eutardigrade Milnesium cf. tardigradum to three doses of gamma radiation (50, 200 and 500 Gy) at the early, middle, and late stage of development. We found that embryos of the middle and late developmental stages were tolerant to all doses, while eggs in the early developmental stage were tolerant only to a dose of 50 Gy, and showed a declining survival with higher dose. We also observed a delay in development of irradiated eggs, suggesting that periods of DNA repair might have taken place after irradiation induced damage. The delay was independent of dose for eggs irradiated in the middle and late stage, possibly indicating a fixed developmental schedule for repair after induced damage. These results show that the tolerance to radiation in tardigrade eggs changes in the course of their development. The mechanisms behind this pattern are unknown, but may relate to changes in mitotic activities over the embryogenesis and/or to activation of response mechanisms to damaged DNA in the course of development.

  • 31. Bengtsson, Linus
    et al.
    Lu, Xin
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Nguyen, Quoc Cuong
    Camitz, Martin
    Hoang, Nguyen Le
    Nguyen, Tuan Anh
    Liljeros, Fredrik
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Thorson, Anna
    Implementation of Web-Based Respondent-Driven Sampling among Men Who Have Sex with Men in Vietnam2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 11, e49417- p.Article in journal (Refereed)
    Abstract [en]

    Objective: Lack of representative data about hidden groups, like men who have sex with men (MSM), hinders an evidence-based response to the HIV epidemics. Respondent-driven sampling (RDS) was developed to overcome sampling challenges in studies of populations like MSM for which sampling frames are absent. Internet-based RDS (webRDS) can potentially circumvent limitations of the original RDS method. We aimed to implement and evaluate webRDS among a hidden population. Methods and Design: criteria were men, aged 18 and above, who had ever had sex with another man and were living in Vietnam. Participants were invited by an MSM friend, logged in, and answered a survey. Participants could recruit up to four MSM friends. We evaluated the system by its success in generating sustained recruitment and the degree to which the sample compositions stabilized with increasing sample size. Results: Twenty starting participants generated 676 participants over 24 recruitment waves. Analyses did not show evidence of bias due to ineligible participation. Estimated mean age was 22 years and 82% came from the two large metropolitan areas. 32 out of 63 provinces were represented. The median number of sexual partners during the last six months was two. The sample composition stabilized well for 16 out of 17 variables. Conclusion: Results indicate that webRDS could be implemented at a low cost among Internet-using MSM in Vietnam. WebRDS may be a promising method for sampling of Internet-using MSM and other hidden groups.

  • 32. Bentley, R. Alexander
    et al.
    Acerbi, Alberto
    University of Bristol (United Kingdom).
    Omerod, Paul
    Lampos, Vasileios
    Books average previous decade of economic misery2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 6, e99737Article in journal (Refereed)
  • 33. Berenguer, Erika
    et al.
    Gardner, Toby A.
    Stockholm University, Stockholm Environment Institute. International Institute for Sustainability, Brazil .
    Barlow, Jos
    Developing Cost-Effective Field Assessments of Carbon Stocks in Human-Modified Tropical Forests2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 8, e0133139Article in journal (Refereed)
    Abstract [en]

    Across the tropics, there is a growing financial investment in activities that aim to reduce emissions from deforestation and forest degradation, such as REDD+. However, most tropical countries lack on-the-ground capacity to conduct reliable and replicable assessments of forest carbon stocks, undermining their ability to secure long-term carbon finance for forest conservation programs. Clear guidance on how to reduce the monetary and time costs of field assessments of forest carbon can help tropical countries to overcome this capacity gap. Here we provide such guidance for cost-effective one-off field assessments of forest carbon stocks. We sampled a total of eight components from four different carbon pools (i.e. aboveground, dead wood, litter and soil) in 224 study plots distributed across two regions of eastern Amazon. For each component we estimated survey costs, contribution to total forest carbon stocks and sensitivity to disturbance. Sampling costs varied thirty-one-fold between the most expensive component, soil, and the least, leaf litter. Large live stems (≥10 cm DBH), which represented only 15% of the overall sampling costs, was by far the most important component to be assessed, as it stores the largest amount of carbon and is highly sensitive to disturbance. If large stems are not taxonomically identified, costs can be reduced by a further 51%, while incurring an error in aboveground carbon estimates of only 5% in primary forests, but 31% in secondary forests. For rapid assessments, necessary to help prioritize locations for carbon- conservation activities, sampling of stems ≥20cm DBH without taxonomic identification can predict with confidence (R2 = 0.85) whether an area is relatively carbon-rich or carbon-poor—an approach that is 74% cheaper than sampling and identifying all the stems ≥10cm DBH. We use these results to evaluate the reliability of forest carbon stock estimates provided by the IPCC and FAO when applied to human-modified forests, and to highlight areas where cost savings in carbon stock assessments could be most easily made.

  • 34. Bermudez, Rafael
    et al.
    Feng, Yuanyuan
    Roleda, Michael Y.
    Tatters, Avery O.
    Hutchins, David A.
    Larsen, Thomas
    Boyd, Philip W.
    Hurd, Catriona L.
    Riebesell, Ulf
    Winder, Monika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Long-Term Conditioning to Elevated pCO(2) and Warming Influences the Fatty and Amino Acid Composition of the Diatom Cylindrotheca fusiformis2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 5, e0123945Article in journal (Refereed)
    Abstract [en]

    The unabated rise in anthropogenic CO2 emissions is predicted to strongly influence the ocean's environment, increasing the mean sea-surface temperature by 4 degrees C and causing a pH decline of 0.3 units by the year 2100. These changes are likely to affect the nutritional value of marine food sources since temperature and CO2 can influence the fatty (FA) and amino acid (AA) composition of marine primary producers. Here, essential amino (EA) and polyunsaturated fatty (PUFA) acids are of particular importance due to their nutritional value to higher trophic levels. In order to determine the interactive effects of CO2 and temperature on the nutritional quality of a primary producer, we analyzed the relative PUFA and EA composition of the diatom Cylindrotheca fusiformis cultured under a factorial matrix of 2 temperatures (14 and 19 degrees C) and 3 partial pressures of CO2 (180, 380, 750 mu atm) for >250 generations. Our results show a decay of similar to 3% and similar to 6% in PUFA and EA content in algae kept at a pCO(2) of 750 mu atm (high) compared to the 380 mu atm (intermediate) CO2 treatments at 14 degrees C. Cultures kept at 19 degrees C displayed a similar to 3% lower PUFA content under high compared to intermediate pCO(2), while EA did not show differences between treatments. Algae grown at a pCO(2) of 180 mu atm (low) had a lower PUFA and AA content in relation to those at intermediate and high CO2 levels at 14 degrees C, but there were no differences in EA at 19 degrees C for any CO2 treatment. This study is the first to report adverse effects of warming and acidification on the EA of a primary producer, and corroborates previous observations of negative effects of these stressors on PUFA. Considering that only similar to 20% of essential biomolecules such as PUFA (and possibly EA) are incorporated into new biomass at the next trophic level, the potential impacts of adverse effects of ocean warming and acidification at the base of the food web may be amplified towards higher trophic levels, which rely on them as source of essential biomolecules.

  • 35.
    Berthet, Pierre
    et al.
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Lansner, Anders
    Stockholm University, Faculty of Science, Numerical Analysis and Computer Science (NADA). Royal Institute of Technology, Sweden.
    Optogenetic Stimulation in a Computational Model of the Basal Ganglia Biases Action Selection and Reward Prediction Error2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, e90578Article in journal (Refereed)
    Abstract [en]

    Optogenetic stimulation of specific types of medium spiny neurons (MSNs) in the striatum has been shown to bias the selection of mice in a two choices task. This shift is dependent on the localisation and on the intensity of the stimulation but also on the recent reward history. We have implemented a way to simulate this increased activity produced by the optical flash in our computational model of the basal ganglia (BG). This abstract model features the direct and indirect pathways commonly described in biology, and a reward prediction pathway (RP). The framework is similar to Actor-Critic methods and to the ventral/ dorsal distinction in the striatum. We thus investigated the impact on the selection caused by an added stimulation in each of the three pathways. We were able to reproduce in our model the bias in action selection observed in mice. Our results also showed that biasing the reward prediction is sufficient to create a modification in the action selection. However, we had to increase the percentage of trials with stimulation relative to that in experiments in order to impact the selection. We found that increasing only the reward prediction had a different effect if the stimulation in RP was action dependent (only for a specific action) or not. We further looked at the evolution of the change in the weights depending on the stage of learning within a block. A bias in RP impacts the plasticity differently depending on that stage but also on the outcome. It remains to experimentally test how the dopaminergic neurons are affected by specific stimulations of neurons in the striatum and to relate data to predictions of our model.

  • 36. Bertrand, Yann
    et al.
    Topel, Mats
    Elvang, Annelie
    Melik, Wessam
    Stockholm University, Faculty of Science, Department of Genetics, Microbiology and Toxicology.
    Johansson, Magnus
    First Dating of a Recombination Event in Mammalian Tick-Borne Flaviviruses2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 2, e31981- p.Article in journal (Refereed)
    Abstract [en]

    The mammalian tick-borne flavivirus group (MTBFG) contains viruses associated with important human and animal diseases such as encephalitis and hemorrhagic fever. In contrast to mosquito-borne flaviviruses where recombination events are frequent, the evolutionary dynamic within the MTBFG was believed to be essentially clonal. This assumption was challenged with the recent report of several homologous recombinations within the Tick-borne encephalitis virus (TBEV). We performed a thorough analysis of publicly available genomes in this group and found no compelling evidence for the previously identified recombinations. However, our results show for the first time that demonstrable recombination (i.e., with large statistical support and strong phylogenetic evidences) has occurred in the MTBFG, more specifically within the Louping ill virus lineage. Putative parents, recombinant strains and breakpoints were further tested for statistical significance using phylogenetic methods. We investigated the time of divergence between the recombinant and parental strains in a Bayesian framework. The recombination was estimated to have occurred during a window of 282 to 76 years before the present. By unravelling the temporal setting of the event, we adduce hypotheses about the ecological conditions that could account for the observed recombination.

  • 37. Bhatara, Anjali
    et al.
    Laukka, Petri
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Cognitive psychology. Södertörn University, Sweden.
    Boll-Avetisyan, Natalie
    Granjon, Lionel
    Anger Elfenbein, Hillary
    Bänziger, Tanja
    Second Language Ability and Emotional Prosody Perception2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 6, e0156855Article in journal (Refereed)
    Abstract [en]

    The present study examines the effect of language experience on vocal emotion perception in a second language. Native speakers of French with varying levels of self-reported English ability were asked to identify emotions from vocal expressions produced by American actors in a forced-choice task, and to rate their pleasantness, power, alertness and intensity on continuous scales. Stimuli included emotionally expressive English speech (emotional prosody) and non-linguistic vocalizations (affect bursts), and a baseline condition with Swiss-French pseudo-speech. Results revealed effects of English ability on the recognition of emotions in English speech but not in non-linguistic vocalizations. Specifically, higher English ability was associated with less accurate identification of positive emotions, but not with the interpretation of negative emotions. Moreover, higher English ability was associated with lower ratings of pleasantness and power, again only for emotional prosody. This suggests that second language skills may sometimes interfere with emotion recognition from speech prosody, particularly for positive emotions.

  • 38.
    Bighiu, Maria Alexandra
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Carney Almroth, Bethanie
    Eriksson Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Metal contamination in harbours impacts life-history traits and metallothionein levels in snails2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 7, e0180157Article in journal (Refereed)
    Abstract [en]

    Harbours with limited water exchange are hotspots of contaminant accumulation. Antifouling paints (AF) contribute to this accumulation by leaching biocides that may affect non-target species. In several leisure boat harbours and reference areas in the Baltic Sea, chronic exposure effects were evaluated using caging experiments with the snail Theodoxus fluviatilis. We analysed variations in ecologically relevant endpoints (mortality, growth and reproduction) in concert with variation in metallothionein-like proteins (MTLP) levels. The latter is a biomarker of exposure to metals, such as copper (Cu) and zinc (Zn), which are used in AF paints as active ingredient and stabilizer, respectively. In addition, environmental samples (water, sediment) were analysed for metal (Cu and Zn) and nutrient (total phosphorous and nitrogen) concentrations. All life-history endpoints were negatively affected by the exposure, with higher mortality, reduced growth and lower fecundity in the harbours compared to the reference sites. Metal concentrations were the key explanatory variables for all observed adverse effects, suggesting that metal-driven toxicity, which is likely to stem from AF paints, is a source of anthropogenic stress for biota in the harbours.

  • 39. Björkenstam, Emma
    et al.
    Hjern, Anders
    Stockholm University, Faculty of Social Sciences, Centre for Health Equity Studies (CHESS).
    Mittendorfer-Rutz, Ellenor
    Vinnerljung, Bo
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Hallqvist, Johan
    Ljung, Rickard
    Multi-Exposure and Clustering of Adverse Childhood Experiences, Socioeconomic Differences and Psychotropic Medication in Young Adults2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 1, e53551Article in journal (Refereed)
    Abstract [en]

    Purpose

    Stressful childhood experiences have negative long-term health consequences. The present study examines the association between adverse childhood experiences, socioeconomic position, and risk of psychotropic medication in young adulthood.

    Methods

    This register-based cohort study comprises the birth cohorts between 1985 and 1988 in Sweden. We followed 362 663 individuals for use of psychotropic medication from January 2006 until December 2008. Adverse childhood experiences were severe criminality among parents, parental alcohol or drug abuse, social assistance recipiency, parental separation or single household, child welfare intervention before the age of 12, mentally ill or suicidal parents, familial death, and number of changes in place of residency. Estimates of risk of psychotropic medication were calculated as odds ratio (OR) with 95% confidence intervals (CIs) using logistic regression analysis.

    Results

    Adverse childhood experiences were associated with increased risks of psychotropic medication. The OR for more than three adverse childhood experiences and risk of psychotropic medication was for women 2.4 (95% CI 2.3–2.5) and for men 3.1 (95% CI 2.9–3.2). The risk of psychotropic medication increased with a higher rate of adverse childhood experiences, a relationship similar in all socioeconomic groups.

    Conclusions

    Accumulation of adverse childhood experiences increases the risk of psychotropic medication in young adults. Parental educational level is of less importance when adjusting for adverse childhood experiences. The higher risk for future mental health problems among children from lower socioeconomic groups, compared to peers from more advantaged backgrounds, seems to be linked to a higher rate of exposure to adverse childhood experiences.

  • 40.
    Blasiak, Robert
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The University of Tokyo, Japan; United Nations University Institute for the Advanced Study of Sustainability, Japan.
    Spijkers, Jessica
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. James Cook University, Australia.
    Tokunaga, Kanae
    Pittman, Jeremy
    Yagi, Nobuyuki
    Österblom, Henrik
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Climate change and marine fisheries: Least developed countries top global index of vulnerability2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 6, e0179632Article in journal (Refereed)
    Abstract [en]

    Future impacts of climate change on marine fisheries have the potential to negatively influence a wide range of socio-economic factors, including food security, livelihoods and public health, and even to reshape development trajectories and spark transboundary conflict. Yet there is considerable variability in the vulnerability of countries around the world to these effects. We calculate a vulnerability index of 147 countries by drawing on the most recent data related to the impacts of climate change on marine fisheries. Building on the Intergovernmental Panel on Climate Change framework for vulnerability, we first construct aggregate indices for exposure, sensitivity and adaptive capacity using 12 primary variables. Seven out of the ten most vulnerable countries on the resulting index are Small Island Developing States, and the top quartile of the index includes countries located in Africa (17), Asia (7), North America and the Caribbean (4) and Oceania (8). More than 87% of least developed countries are found within the top half of the vulnerability index, while the bottom half includes all but one of the Organization for Economic Co-operation and Development member states. This is primarily due to the tremendous variation in countries' adaptive capacity, as no such trends are evident from the exposure or sensitivity indices. A negative correlation exists between vulnerability and per capita carbon emissions, and the clustering of states at different levels of development across the vulnerability index suggests growing barriers to meeting global commitments to reducing inequality, promoting human well-being and ensuring sustainable cities and communities. The index provides a useful tool for prioritizing the allocation of climate finance, as well as activities aimed at capacity building and the transfer of marine technology.

  • 41. Blix, Eva
    et al.
    Perski, Aleksander
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Berglund, Hans
    Savic, Ivanka
    Long-Term Occupational Stress Is Associated with Regional Reductions in Brain Tissue Volumes2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 6, e64065- p.Article in journal (Refereed)
    Abstract [en]

    There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM) and white matter (WM) volumes, and the volumes of hippocampus, caudate, and putamen - structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment.

  • 42.
    Boettcher, Johanna
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Leek, Linda
    Matson, Lisa
    Holmes, Emily A.
    Browning, Michael
    MacLeod, Colin
    Andersson, Gerhard
    Carlbring, Per
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Internet-Based Attention Bias Modification for Social Anxiety: A Randomised Controlled Comparison of Training towards Negative and Training Towards Positive Cues2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 9, e71760- p.Article in journal (Refereed)
    Abstract [en]

    Biases in attention processes are thought to play a crucial role in the aetiology and maintenance of Social Anxiety Disorder (SAD). The goal of the present study was to examine the efficacy of a programme intended to train attention towards positive cues and a programme intended to train attention towards negative cues. In a randomised, controlled, double-blind design, the impact of these two training conditions on both selective attention and social anxiety were compared to that of a control training condition. A modified dot probe task was used, and delivered via the internet. A total of 129 individuals, diagnosed with SAD, were randomly assigned to one of these three conditions and took part in a 14-day programme with daily training/control sessions. Participants in all three groups did not on average display an attentional bias prior to the training. Critically, results on change in attention bias implied that significantly differential change in selective attention to threat was not detected in the three conditions. However, symptoms of social anxiety reduced significantly from pre- to follow-up-assessment in all three conditions (d(within) = 0.63-1.24), with the procedure intended to train attention towards threat cues producing, relative to the control condition, a significantly greater reduction of social fears. There were no significant differences in social anxiety outcome between the training condition intended to induce attentional bias towards positive cues and the control condition. To our knowledge, this is the first RCT where a condition intended to induce attention bias to negative cues yielded greater emotional benefits than a control condition. Intriguingly, changes in symptoms are unlikely to be by the mechanism of change in attention processes since there was no change detected in bias per se. Implications of this finding for future research on attention bias modification in social anxiety are discussed.

  • 43. Boman, Krister K.
    et al.
    Kjällander, Ylva
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Karolinska Institute .
    Eksborg, Staffan
    Becker, Jeremy
    Impact of Prior Traumatic Life Events on Parental Early Stage Reactions following a Child's Cancer2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 3, e57556- p.Article in journal (Refereed)
    Abstract [en]

    Background: In pediatric oncology, effective clinic-based management of acute and long-term distress in families calls for investigation of determinants of parents' psychological response to the child's cancer. We examined the relationship between parents' prior exposure to traumatic life events (TLE) and the occurrence of posttraumatic stress symptoms (PTSS) following their child's cancer diagnosis. Factors mediating the TLE-PTSS relationship were analyzed. Methodology: The study comprised 169 parents (97 mothers, 72 fathers) of 103 cancer diagnosed children (median age: 5,9 years; range 0.1-19.7 years). Thirty five parents were of immigrant origin (20.7%). Prior TLE were collated using a standardized questionnaire, PTSS was assessed using the Impact of Events-Revised (IES-R) questionnaire covering intrusion, avoidance and hyperarousal symptoms. The predictive significance of prior TLE on PTSS was tested in adjusted regression models. Results: Mothers demonstrated more severe PTSS across all symptom dimensions. TLE were associated with significantly increased hyperarousal symptoms. Parents' gender, age and immigrant status did not significantly influence the TLE-PTSS relationship. Conclusions: Prior traumatic life-events aggravate posttraumatic hyperarousal symptoms. In clinic-based psychological care of parents of high-risk pediatric patients, attention needs to be paid to life history, and to heightened vulnerability to PTSS associated with female gender.

  • 44. Borghans, Lex
    et al.
    Golsteyn, Bart H. H.
    Stockholm University, Faculty of Social Sciences, The Swedish Institute for Social Research (SOFI). Maastricht University, The Netherlands.
    Stenberg, Anders
    Stockholm University, Faculty of Social Sciences, The Swedish Institute for Social Research (SOFI).
    Does Expert Advice Improve Educational Choice?2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 12, e0145378Article in journal (Refereed)
    Abstract [en]

    This paper reports evidence that an individual meeting with a study counselor at high school significantly improves the quality of choice of tertiary educational field, as self-assessed 18 months after graduation from college. To address endogeneity, we explore the variation in study counseling practices between schools as an instrumental variable (IV). Following careful scrutiny of the validity of the IV, our results indicate a significant and positive influence of study counseling on the quality of educational choice, foremost among males and those with low educated parents. The overall result is stable across a number of robustness checks.

  • 45.
    Borysov, Stanislav S.
    et al.
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Los Alamos National Laboratory, USA; KTH Royal Institute of Technology, Sweden.
    Balatsky, Alexander V.
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Los Alamos National Laboratory, USA.
    Cross-Correlation Asymmetries and Causal Relationships between Stock and Market Risk2014In: PLoS ONE, ISSN 1932-6203, Vol. 9, no 8, e105874- p.Article in journal (Refereed)
    Abstract [en]

    We study historical correlations and lead-lag relationships between individual stock risk (volatility of daily stock returns) and market risk (volatility of daily returns of a market-representative portfolio) in the US stock market. We consider the cross-correlation functions averaged over all stocks, using 71 stock prices from the Standard & Poor's 500 index for 1994-2013. We focus on the behavior of the cross-correlations at the times of financial crises with significant jumps of market volatility. The observed historical dynamics showed that the dependence between the risks was almost linear during the US stock market downturn of 2002 and after the US housing bubble in 2007, remaining at that level until 2013. Moreover, the averaged cross-correlation function often had an asymmetric shape with respect to zero lag in the periods of high correlation. We develop the analysis by the application of the linear response formalism to study underlying causal relations. The calculated response functions suggest the presence of characteristic regimes near financial crashes, when the volatility of an individual stock follows the market volatility and vice versa.

  • 46.
    Borysov, Stanislav S.
    et al.
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Geilhufe, R. Matthias
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Balatsky, Alexander V.
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). ETH Zürich, Germany.
    Organic materials database: An open-access online database for data mining2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 2, e0171501Article in journal (Refereed)
    Abstract [en]

    We present an organic materials database (OMDB) hosting thousands of Kohn-Sham electronic band structures, which is freely accessible online at http://omdb.diracmaterials.org. The OMDB focus lies on electronic structure, density of states and other properties for purely organic and organometallic compounds that are known to date. The electronic band structures are calculated using density functional theory for the crystal structures contained in the Crystallography Open Database. The OMDB web interface allows users to retrieve materials with specified target properties using non-trivial queries about their electronic structure. We illustrate the use of the OMDB and how it can become an organic part of search and prediction of novel functional materials via data mining techniques. As a specific example, we provide data mining results for metals and semiconductors, which are known to be rare in the class of organic materials.

  • 47. Boström, Jannika E.
    et al.
    Dimitrova, Marina
    Stockholm University, Faculty of Science, Department of Zoology. Uppsala University, Sweden.
    Canton, Cindy
    Håstad, Olle
    Qvarnström, Anna
    Ödeen, Anders
    Ultra-Rapid Vision in Birds2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 3, e0151099Article in journal (Refereed)
    Abstract [en]

    Flying animals need to accurately detect, identify and track fast-moving objects and these behavioral requirements are likely to strongly select for abilities to resolve visual detail in time. However, evidence of highly elevated temporal acuity relative to non-flying animals has so far been confined to insects while it has been missing in birds. With behavioral experiments on three wild passerine species, blue tits, collared and pied flycatchers, we demonstrate temporal acuities of vision far exceeding predictions based on the sizes and metabolic rates of these birds. This implies a history of strong natural selection on temporal resolution. These birds can resolve alternating light-dark cycles at up to 145 Hz (average: 129, 127 and 137, respectively), which is ca. 50 Hz over the highest frequency shown in any other vertebrate. We argue that rapid vision should confer a selective advantage in many bird species that are ecologically similar to the three species examined in our study. Thus, rapid vision may be a more typical avian trait than the famously sharp vision found in birds of prey.

  • 48.
    Boström, Stéphanie
    et al.
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Ibitokou, Samad
    Oesterholt, Mayke
    Schmiegelow, Christentze
    Persson, Jan-Olov
    Stockholm University, Faculty of Science, Department of Mathematics.
    Minja, Daniel
    Lusingu, John
    Lemnge, Martha
    Fievet, Nadine
    Deloron, Philippe
    Luty, Adrian J. F.
    Troye-Blomberg, Marita
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Biomarkers of Plasmodium falciparum infection during pregnancy in women living in Northeastern Tanzania2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 11, e48763- p.Article in journal (Refereed)
    Abstract [en]

    In pregnant women, Plasmodium falciparum infections are an important cause of maternal morbidity as well as fetal and neonatal mortality. Erythrocytes infected by these malaria-causing parasites accumulate through adhesive interactions in placental intervillous spaces, thus evading detection in peripheral blood smears. Sequestered infected erythrocytes induce inflammation, offering the possibility of detecting inflammatory mediators in peripheral blood that could act as biomarkers of placental infection. In a longitudinal, prospective study in Tanzania, we quantified a range of different cytokines, chemokines and angiogenic factors in peripheral plasma samples, taken on multiple sequential occasions during pregnancy up to and including delivery, from P. falciparum-infected women and matched uninfected controls. The results show that during healthy, uninfected pregnancies the levels of most of the panel of molecules we measured were largely unchanged except at delivery. In women with P. falciparum, however, both comparative and longitudinal assessments consistently showed that the levels of IL-10 and IP-10 increased significantly whilst that of RANTES decreased significantly, regardless of gestational age at the time the infection was detected. ROC curve analysis indicated that a combination of increased IL-10 and IP-10 levels and decreased RANTES levels might be predictive of P. falciparum infections. In conclusion, our data suggest that host biomarkers in peripheral blood may represent useful diagnostic markers of P. falciparum infection during pregnancy, but placental histology results would need to be included to verify these findings.

  • 49. Brenner, M. Harvey
    et al.
    Andreeva, Elena
    Theorell, Töres
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Goldberg, Marcel
    Westerlund, Hugo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Leineweber, Constanze
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Magnusson Hanson, Linda L.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Imbernon, Ellen
    Bonnaud, Sophie
    Organizational downsizing and depressive symptoms in the European recession: the experience of workers in France, Hungary, Sweden and the United kingdom2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 5, e97063Article in journal (Refereed)
    Abstract [en]

    Background: Organizational downsizing has become highly common during the global recession of the late 2000s with severe repercussions on employment. We examine whether the severity of the downsizing process is associated with a greater likelihood of depressive symptoms among displaced workers, internally redeployed workers and lay-off survivors. Methods: A cross-sectional survey involving telephone interviews was carried out in France, Hungary, Sweden and the United Kingdom. The study analyzes data from 758 workers affected by medium-and large-scale downsizing, using multiple logistic regression. Main Results: Both unemployment and surviving layoffs were significantly associated with depressive symptoms, as compared to reemployment, but the perceived procedural justice of a socially responsible downsizing process considerably mitigated the odds of symptoms. Perception of high versus low justice was assessed along several downsizing dimensions. In the overall sample, chances to have depressive symptoms were significantly reduced if respondents perceived the process as transparent and understandable, fair and unbiased, well planned and democratic; if they trusted the employer's veracity and agreed with the necessity for downsizing. The burden of symptoms was significantly greater if the process was perceived to be chaotic. We further tested whether perceived justice differently affects the likelihood of depressive symptoms among distinct groups of workers. Findings were that the odds of symptoms largely followed the same patterns of effects across all groups of workers. Redeploying and supporting surplus employees through the career change process-rather than forcing them to become unemployed-makes a substantial difference as to whether they will suffer from depressive symptoms. Conclusions: While depressive symptoms affect both unemployed and survivors, a just and socially responsible downsizing process is important for the emotional health of workers.

  • 50. Brodin, Johanna
    et al.
    Mild, Mattias
    Hedskog, Charlotte
    Sherwood, Ellen
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Leitner, Thomas
    Andersson, Bjoern
    Albert, Jan
    PCR-Induced Transitions Are the Major Source of Error in Cleaned Ultra-Deep Pyrosequencing Data2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 7, e70388Article in journal (Refereed)
    Abstract [en]

    Background: Ultra-deep pyrosequencing (UDPS) is used to identify rare sequence variants. The sequence depth is influenced by several factors including the error frequency of PCR and UDPS. This study investigated the characteristics and source of errors in raw and cleaned UDPS data. Results: UDPS of a 167-nucleotide fragment of the HIV-1 SG3Denv plasmid was performed on the Roche/454 platform. The plasmid was diluted to one copy, PCR amplified and subjected to bidirectional UDPS on three occasions. The dataset consisted of 47,693 UDPS reads. Raw UDPS data had an average error frequency of 0.30% per nucleotide site. Most errors were insertions and deletions in homopolymeric regions. We used a cleaning strategy that removed almost all indel errors, but had little effect on substitution errors, which reduced the error frequency to 0.056% per nucleotide. In cleaned data the error frequency was similar in homopolymeric and non-homopolymeric regions, but varied considerably across sites. These site-specific error frequencies were moderately, but still significantly, correlated between runs (r = 0.15-0.65) and between forward and reverse sequencing directions within runs (r = 0.33-0.65). Furthermore, transition errors were 48-times more common than transversion errors (0.052% vs. 0.001%; p<0.0001). Collectively the results indicate that a considerable proportion of the sequencing errors that remained after data cleaning were generated during the PCR that preceded UDPS. Conclusions: A majority of the sequencing errors that remained after data cleaning were introduced by PCR prior to sequencing, which means that they will be independent of platform used for next-generation sequencing. The transition vs. transversion error bias in cleaned UDPS data will influence the detection limits of rare mutations and sequence variants.

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