139 research outputs found

    A bi‐organellar phylogenomic study of Pandanales: inference of higher‐order relationships and unusual rate‐variation patterns

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    We used a bi‐organellar phylogenomic approach to address higher‐order relationships in Pandanales, including the first molecular phylogenetic study of the panama‐hat family, Cyclanthaceae. Our genus‐level study of plastid and mitochondrial gene sets includes a comprehensive sampling of photosynthetic lineages across the order, and provides a framework for investigating clade ages, biogeographic hypotheses and organellar molecular evolution. Using multiple inference methods and both organellar genomes, we recovered mostly congruent and strongly supported relationships within and between families, including the placement of fully mycoheterotrophic Triuridaceae. Cyclanthaceae and Pandanaceae plastomes have slow substitution rates, contributing to weakly supported plastid‐based relationships in Cyclanthaceae. While generally slowly evolving, mitochondrial genomes exhibit sporadic rate elevation across the order. However, we infer well‐supported relationships even for slower evolving mitochondrial lineages in Cyclanthaceae. Clade age estimates across photosynthetic lineages are largely consistent with previous studies, are well correlated between the two organellar genomes (with slightly younger inferences from mitochondrial data), and support several biogeographic hypotheses. We show that rapidly evolving non‐photosynthetic lineages may bias age estimates upwards at neighbouring photosynthetic nodes, even using a relaxed clock model. Finally, we uncovered new genome structural variants in photosynthetic taxa at plastid inverted repeat boundaries that show promise as interfamilial phylogenetic markers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/33/cla12417-sup-0025-TableS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/32/cla12417-sup-0017-FigS17.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/31/cla12417-sup-0004-FigS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/30/cla12417-sup-0019-FigS19.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/29/cla12417-sup-0020-FigS20.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/28/cla12417_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/27/cla12417-sup-0005-FigS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/26/cla12417-sup-0012-FigS12.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/25/cla12417-sup-0007-FigS7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/24/cla12417-sup-0022-FigS22.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/23/cla12417-sup-0029-TableS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/22/cla12417-sup-0010-FigS10.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/21/cla12417-sup-0011-FigS11.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/20/cla12417-sup-0014-FigS14.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/19/cla12417-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/18/cla12417-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/17/cla12417.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/16/cla12417-sup-0030-TableS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/15/cla12417-sup-0021-FigS21.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/14/cla12417-sup-0023-FigS23.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/13/cla12417-sup-0009-FigS9.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/12/cla12417-sup-0031-TableS7.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/11/cla12417-sup-0006-FigS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/10/cla12417-sup-0003-FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/9/cla12417-sup-0024-FigS24.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/8/cla12417-sup-0008-FigS8.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/7/cla12417-sup-0028-TableS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/6/cla12417-sup-0016-FigS16.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/5/cla12417-sup-0013-FigS13.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/4/cla12417-sup-0018-FigS18.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/3/cla12417-sup-0026-TableS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/2/cla12417-sup-0015-FigS15.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162810/1/cla12417-sup-0027-TableS3.pd

    Long-term effects of cranial irradiation and intrathecal chemotherapy in treatment of childhood leukemia: a MEG study of power spectrum and correlated cognitive dysfunction

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    <p>Abstract</p> <p>Background</p> <p>Prophylaxis to prevent relapses in the central nervous system after childhood acute lymphoblastic leukemia (ALL) used to consist of both intrathecal chemotherapy (CT) and cranial irradiation (CRT). CRT was mostly abolished in the eighties because of its neurotoxicity, and replaced with more intensive intrathecal CT. In this study, a group of survivors treated with CRT before 1983 and another group treated without CRT thereafter are investigated 20–25 years later, giving a much stronger perspective on long-term quality of life than previous studies. The outcomes will help to better understand these groups’ current needs and will aid in anticipating late effects of prophylactic CRT that is currently applied for other diseases. This study evaluates oscillatory neuronal activity in these long-term survivors. Power spectrum deviations are hypothesized to correlate with cognitive dysfunction.</p> <p>Methods</p> <p>Resting state eyes-closed magnetoencephalography (MEG) recordings were obtained from 14 ALL survivors treated with CT + CRT, 18 treated with CT alone and 35 controls. Relative spectral power was calculated in the ÎŽ, Ξ, α1, α2, ÎČ and Îł frequency bands. The Amsterdam Neuropsychological Tasks (ANT) program was used to assess cognition in the executive functions domain. MEG data and ANT scores were correlated.</p> <p>Results</p> <p>In the CT + CRT group, relative Ξ power was slightly increased (p = 0.069) and α2 power was significantly decreased (p = 0.006). The CT + CRT group performed worse on various cognitive tests. A deficiency in visuomotor accuracy, especially of the right hand, could be clearly associated with the deviating regional Ξ and α2 powers (0.471 < r < 0.697). A significant association between decreased regional α2 power and less attentional fluctuations was found for CT + CRT patients as well as controls (0.078 < r < 0.666). Patients treated with CT alone displayed a power spectrum similar to controls, except for a significantly increased level of left frontal α2 power (p = 0.030).</p> <p>Conclusions</p> <p>The tendency towards global slowing of brain oscillatory activity, together with the fact that dementia has been reported as a late effect of CRT and the neuropsychological deficiencies currently present, suggest that the irradiated brain might be aging faster and could be at risk for early‐onset dementia. The CT group showed no signs of early aging.</p

    Cognitive Control and Individual Differences in Economic Ultimatum Decision-Making

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    Much publicity has been given to the fact that people's economic decisions often deviate from the rational predictions of standard economic models. In the classic ultimatum game, for example, most people turn down financial gains by rejecting unequal monetary splits. The present study points to neglected individual differences in this debate. After participants played the ultimatum game we tested for individual differences in cognitive control capacity of the most and least economic responders. The key finding was that people who were higher in cognitive control, as measured by behavioral (Go/No-Go performance) and neural (No-Go N2 amplitude) markers, did tend to behave more in line with the standard models and showed increased acceptance of unequal splits. Hence, the cognitively highest scoring decision-makers were more likely to maximize their monetary payoffs and adhere to the standard economic predictions. Findings question popular claims with respect to the rejection of standard economic models and the irrationality of human economic decision-making

    Best practices in data analysis and sharing in neuroimaging using MRI

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    Given concerns about the reproducibility of scientific findings, neuroimaging must define best practices for data analysis, results reporting, and algorithm and data sharing to promote transparency, reliability and collaboration. We describe insights from developing a set of recommendations on behalf of the Organization for Human Brain Mapping, and identify barriers that impede these practices, including how the discipline must change to fully exploit the potential of the world’s neuroimaging data

    Scientific Guidance on the data required for the risk assessment of flavourings to be used in or on foods

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    Following a request from the European Commission, EFSA developed a new scientific guidance to assist applicants in the preparation of applications for the authorisation of flavourings to be used in or on foods. This guidance applies to applications for a new authorisation as well as for a modification of an existing authorisation of a food flavouring, submitted under Regulation (EC) No 1331/2008. It defines the scientific data required for the evaluation of those food flavourings for which an evaluation and approval is required according to Article 9 of Regulation (EC) No 1334/2008. This applies to flavouring substances, flavouring preparations, thermal process flavourings, flavour precursors, other flavourings and source materials, as defined in Article 3 of Regulation (EC) No 1334/2008. Information to be provided in all applications relates to: (a) the characterisation of the food flavouring, including the description of its identity, manufacturing process, chemical composition, specifications, stability and reaction and fate in foods; (b) the proposed uses and use levels and the assessment of the dietary exposure and (c) the safety data, including information on the genotoxic potential of the food flavouring, toxicological data other than genotoxicity and information on the safety for the environment. For the toxicological studies, a tiered approach is applied, for which the testing requirements, key issues and triggers are described. Applicants should generate the data requested in each section to support the safety assessment of the food flavouring. Based on the submitted data, EFSA will assess the safety of the food flavouring and conclude whether or not it presents risks to human health and to the environment, if applicable, under the proposed conditions of use

    Brainhack: a collaborative workshop for the open neuroscience community

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    International audienceBrainhack events offer a novel workshop format with participant-generated content that caters to the rapidly growing open neuroscience community. Including components from hackathons and unconferences, as well as parallel educational sessions, Brainhack fosters novel collaborations around the interests of its attendees. Here we provide an overview of its structure, past events, and example projects. Additionally, we outline current innovations such as regional events and post-conference publications. Through introducing Brainhack to the wider neuroscience community, we hope to provide a unique conference format that promotes the features of collaborative, open science

    Mutational Analysis of Photosystem I of Synechocystis sp. PCC 6803: The Role of Four Conserved Aromatic Residues in the j-helix of PsaB

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    Photosystem I is the light-driven plastocyanin-ferredoxin oxidoreductase in the photosynthetic electron transfer of cyanobacteria and plants. Two histidyl residues in the symmetric transmembrane helices A-j and B-j provide ligands for the P700 chlorophyll molecules of the reaction center of photosystem I. To determine the role of conserved aromatic residues adjacent to the histidyl molecule in the helix of B-j, we generated six site-directed mutants of the psaB gene in Synechocystis sp. PCC 6803. Three mutant strains with W645C, W643C/A644I and S641C/V642I substitutions could grow photoautotrophically and showed no obvious reduction in the photosystem I activity. Kinetics of P700 re-reduction by plastocyanin remained unaltered in these mutants. In contrast, the strains with H651C/L652M, F649C/G650I and F647C substitutions could not grow under photoautotrophic conditions because those mutants had low photosystem I activity, possibly due to low levels of proteins. A procedure to select spontaneous revertants from the mutants that are incapable to photoautotrophic growth resulted in three revertants that were used in this study. The molecular analysis of the spontaneous revertants suggested that an aromatic residue at F647 and a small residue at G650 may be necessary for maintaining the structural integrity of photosystem I. The (P700+ - P700) steady-state absorption difference spectrum of the revertant F647Y has a ∌5 nm narrower peak than the recovered wild-type, suggesting that additional hydroxyl group of this revertant may participate in the interaction with the special pair while the photosystem I complexes of the F649C/G650T and H651Q mutants closely resemble the wild-type spectrum. The results presented here demonstrate that the highly conserved residues W645, W643 and F649 are not critical for maintaining the integrity and in mediating electron transport from plastocyanin to photosystem I. Our data suggest that an aromatic residue is required at position of 647 for structural integrity and/or function of photosystem I

    Preference for biological motion is reduced in ASD: implications for clinical trials and the search for biomarkers

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    Background: The neurocognitive mechanisms underlying autism spectrum disorder (ASD) remain unclear. Progress has been largely hampered by small sample sizes, variable age ranges and resulting inconsistent findings. There is a pressing need for large definitive studies to delineate the nature and extent of key case/control differences to direct research towards fruitful areas for future investigation. Here we focus on perception of biological motion, a promising index of social brain function which may be altered in ASD. In a large sample ranging from childhood to adulthood, we assess whether biological motion preference differs in ASD compared to neurotypical participants (NT), how differences are modulated by age and sex and whether they are associated with dimensional variation in concurrent or later symptomatology. Methods: Eye-tracking data were collected from 486 6-to-30-year-old autistic (N = 282) and non-autistic control (N = 204) participants whilst they viewed 28 trials pairing biological (BM) and control (non-biological, CTRL) motion. Preference for the biological motion stimulus was calculated as (1) proportion looking time difference (BM-CTRL) and (2) peak look duration difference (BM-CTRL). Results: The ASD group showed a present but weaker preference for biological motion than the NT group. The nature of the control stimulus modulated preference for biological motion in both groups. Biological motion preference did not vary with age, gender, or concurrent or prospective social communicative skill within the ASD group, although a lack of clear preference for either stimulus was associated with higher social-communicative symptoms at baseline. Limitations: The paired visual preference we used may underestimate preference for a stimulus in younger and lower IQ individuals. Our ASD group had a lower average IQ by approximately seven points. 18% of our sample was not analysed for various technical and behavioural reasons. Conclusions: Biological motion preference elicits small-to-medium-sized case–control effects, but individual differences do not strongly relate to core social autism associated symptomatology. We interpret this as an autistic difference (as opposed to a deficit) likely manifest in social brain regions. The extent to which this is an innate difference present from birth and central to the autistic phenotype, or the consequence of a life lived with ASD, is unclear
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