234 research outputs found

    The first evidence of a host-to-parasite mitochondrial gene transfer in Orobanchaceae

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    Several parasitic plants are known to have acquired mitochondrial genes via a horizontal transfer from their hosts. However, mitochondrial gene transfer in this direction has not yet been found in the parasite-rich family Orobanchaceae. Based on a phylogenetic analysis of the mitochondrial atp6 gene in selected species of Orobanche s.l., we provide evidence of a host-to-parasite transfer of this gene in O. coerulescens, which is a Eurasiatic species that parasitises Artemisia (Asteraceae). We did not find the original Orobanche atp6 gene in this species, which suggests that it has been replaced by a gene that was acquired from Asteraceae. In addition, our data suggest the occurrence of a second HGT event in the atp6 sequence - from Asteraceae to Phelipanche. Our results support the view that the transfer of genetic material from hosts to parasites influences the mitochondrial genome evolution in the latter

    Small mammals as indicators of cryptic plant species diversity in the central Chilean plant endemicity hotspot

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    AbstractIndicator species could help to compensate for a shortfall of knowledge about the diversity and distributions of undersampled and cryptic species. This paper provides background knowledge about the ecological interactions that affect and are affected by herbaceous diversity in central Chile, as part of the indicator species selection process. We focus on the ecosystem engineering role of small mammals, primarily the degu Octodon degus. We also consider the interacting effects of shrubs, trees, avian activity, livestock, slope, and soil quality on herbaceous communities in central Chile. We sampled herbaceous diversity on a private landholding characterized by a mosaic of savanna, grassland and matorral, across a range of degu disturbance intensities. We find that the strongest factors affecting endemic herbaceous diversity are density of degu runways, shrub cover and avian activity. Our results show that the degu, a charismatic and easily identifiable and countable species, could be used as an indicator species to aid potential conservation actions such as private protected area uptake. We map areas in central Chile where degus may indicate endemic plant diversity. This area is larger than expected, and suggests that significant areas of endemic plant communities may still exist, and should be identified and protected

    Inhibition of the \u3cem\u3edapE\u3c/em\u3e-Encoded \u3cem\u3eN\u3c/em\u3e-Succinyl- ÊŸ, ÊŸ-diaminopimelic Acid Desuccinylase from \u3cem\u3eNeisseria meningitidis\u3c/em\u3e by ÊŸ-Captopril

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    Binding of the competitive inhibitor ʟ-captopril to the dapE-encoded N-succinyl-ʟ, ʟ-diaminopimelic acid desuccinylase from Neisseria meningitidis (NmDapE) was examined by kinetic, spectroscopic, and crystallographic methods. ʟ-Captopril, an angiotensin-converting enzyme (ACE) inhibitor, was previously shown to be a potent inhibitor of the DapE from Haemophilus influenzae (HiDapE) with an IC50 of 3.3 μM and a measured Ki of 1.8 μM and displayed a dose-responsive antibiotic activity toward Escherichia coli. ʟ-Captopril is also a competitive inhibitor of NmDapE with a Ki of 2.8 μM. To examine the nature of the interaction of ʟ-captopril with the dinuclear active site of DapE, we have obtained electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) data for the enzymatically hyperactive Co(II)-substituted forms of both HiDapE and NmDapE. EPR and MCD data indicate that the two Co(II) ions in DapE are antiferromagnetically coupled, yielding an S = 0 ground state, and suggest a thiolate bridge between the two metal ions. Verification of a thiolate-bridged dinuclear complex was obtained by determining the three-dimensional X-ray crystal structure of NmDapE in complex with ʟ-captopril at 1.8 Å resolution. Combination of these data provides new insights into binding of ʟ-captopril to the active site of DapE enzymes as well as important inhibitor–active site residue interaction’s. Such information is critical for the design of new, potent inhibitors of DapE enzymes

    Evaluation of the Influence of a Thioether Substituent on the Solid State and Solution Properties of N\u3csub\u3e3\u3c/sub\u3eS-ligated Copper(II) Complexes

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    Admixture of a N3S(thioether) ligand having two internal hydrogen bond donors (pbnpa: N-2-(phenylthio)ethyl-N,N-bis-((6-neopentylamino-2-pyridyl)methyl)amine; ebnpa: N-2-(ethylthio)ethyl-N,N-bis-((6-neopentylamino-2-pyridyl)methyl)amine) with equimolar amounts of Cu(ClO4)2·6H2O and NaX (X = Cl−, NCO−, or N3−) in CH3OH/H2O yielded the mononuclear Cu(II) derivatives [(pbnpa)Cu–Cl]ClO4 (1), [(ebnpa)Cu–Cl]ClO4 (2), [(pbnpa)Cu–NCO]ClO4 (3), [(ebnpa)Cu–NCO]ClO4 (4), [(pbnpa)Cu–N3]ClO4 (5), and [(ebnpa)Cu–N3]ClO4 (6). Each complex was characterized by FTIR, UV-VIS, EPR, and elemental analysis. Complexes 1, 2, 3 and 6 were characterized by X-ray crystallography. The structural studies revealed that [(pbnpa)Cu–X]ClO4 derivatives (1, 3) exhibit a distorted square pyramidal type geometry, whereas [(ebnpa)Cu–X]ClO4 complexes (2, 6) may be classified as distorted trigonal bipyramidal. EPR studies in CH3OH/CH3CN solution revealed that 1–6 exhibit an axial type spectrum with g∥ \u3e g⊥ \u3e 2.0 and A∥ = 15–17 mT, consistent with a square pyramidal based geometry for the Cu(II) center in each complex. A second species detected in the EPR spectra of 2 and 6 has a smaller A∥ value, consistent with greater spin delocalization on to sulfur, and likely results from geometric distortion of the [(ebnpa)Cu(II)–X]+ ions present in 2 and 6

    Metabolic profiling of zebrafish embryo development from blastula period to early larval stages

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    The zebrafish embryo is a popular model for drug screening, disease modelling and molecular genetics. In this study, samples were obtained from zebrafish at different developmental stages. The stages that were chosen were 3/4, 4/5, 24, 48, 72 and 96 hours post fertilization (hpf). Each sample included fifty embryos. The samples were analysed using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). Principle component analysis (PCA) was applied to get an overview of the data and orthogonal projection to latent structure discriminant analysis (OPLS-DA) was utilised to discriminate between the developmental stages. In this way, changes in metabolite profiles during vertebrate development could be identified. Using a GC-TOF-MS metabolomics approach it was found that nucleotides and metabolic fuel (glucose) were elevated at early stages of embryogenesis, whereas at later stages amino acids and intermediates in the Krebs cycle were abundant. This agrees with zebrafish developmental biology, as organs such as the liver and pancreas develop at later stages. Thus, metabolomics of zebrafish embryos offers a unique opportunity to investigate large scale changes in metabolic processes during important developmental stages in vertebrate development. In terms of stability of the metabolic profile and viability of the embryos, it was concluded at 72 hpf was a suitable time point for the use of zebrafish as a model system in numerous scientific applications

    Phylogeny and historical biogeography analysis support Caucasian and Mediterranean centres of origin of key holoparasitic Orobancheae (Orobanchaceae) lineages

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    The extensive diversity of the tribe Orobancheae, the most species-rich lineage of holoparasitic Orobanchaceae, is concentrated in the Caucasus and Mediterranean regions of the Old World. This extant diversity has inspired hypotheses that these regions are also centres of origin of its key lineages, however the ability to test hypotheses has been limited by a lack of sampling and phylogenetic information about the species, especially in the Caucasus region. First, we assessed the phylogenetic relationships of several poorly known, problematic, or newly described species and host-races of four genera of Orobancheae occurring in the Caucasus region–Cistanche, Phelypaea, Phelipanche and Orobanche–using nuclear ribosomal (ITS) and plastid (trnL–trnF) sequence data. Then we applied a probablistic dispersal-extinction-cladogenesis model of historical biogeography across a more inclusive clade of holoparasites, to explicitly test hypotheses of Orobancheae diversification and historical biogeography shifts. In sum, we sampled 548 sequences (including 196 newly generated) from 13 genera, 140 species, and 175 taxa across 44 countries. We find that the Western Asia (particularly the Caucasus) and the Mediterranean are the centre of origin for large clades of holoparasitic Orobancheae within the last 6 million years. In the Caucasus, the centres of diversity are composed both of long-branch taxa and shallow, recently diversified clades, while Orobancheae diversity in the Mediterranean appears to represent mainly recent diversification

    The 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) Part II: Psychometric Adequacy for Categorical Measurement of Selected DSM-5 Disorders

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    Objectives: To compare the reliability and convergent validity of parent assessments from the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID—a structured diagnostic interview) and the Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) symptom checklist for classifying conduct disorder (CD), conduct disorder or oppositional defiant disorder (CD-ODD), attention-deficit hyperactivity disorder (ADHD), major depressive disorder (MDD), generalized anxiety disorder (GAD), and separation anxiety disorder (SAD) based on DSM-5 criteria. Methods: Data came from 283 parent-youth dyads aged 9 to 18 years. Parents and youth completed the assessments separately on 2 different occasions 7 to 14 days apart. After converting the OCHS-EBS scale scores to binary disorder classifications, we compare test-retest reliability estimates and use structural equation modelling (SEM) to compare estimates of convergent validity for the same disorders assessed by each instrument. Results: Average test-retest reliabilities based on κ were 0.71 (MINI-KID) and 0.67 (OCHS-EBS). The average β coefficients for 3 latent measures comprising the following indicators—parent perceptions of youth mental health need and impairment, diagnosis of specific disorders based on health professional communications and youth taking prescribed medication, and youth classifications of disorder based on the MINI-KID—were 0.67 (MINI-KID) and 0.69 (OCHS-EBS). Conclusion: The OCHS-EBS and MINI-KID achieve comparable levels of reliability and convergent validity for classifying child psychiatric disorder. The flexibility, low cost, and minimal respondent burden of checklists for classifying disorder make them well suited for studying disorder in the general population and screening in clinical settings

    The 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) Part I: A Checklist for Dimensional Measurement of Selected DSM-5 Disorders

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    Objectives: To describe the development and psychometric properties of the 2014 Ontario Child Health Study Emotional Behavioural Scales (OCHS-EBS) for dimensional measurement of 7 disorders based on criteria from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Methods: Scale items were selected by agreement among 19 child psychologists and psychiatrists rating the correspondence between item descriptions and DSM-5 symptoms. Psychometric evaluation of the item properties and parent/caregiver and youth scales came from a general population study of 10,802 children and youth aged 4 to 17 years in 6537 families. Test-retest reliability data were collected from a subsample of 280 children and their caregivers who independently completed the OCHS-EBS checklist on 2 occasions 7 to 14 days apart. Structural equation modelling was used to assess internal and external convergent and discriminant validity—the latter tested against the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID). Results: Confirmatory factor analyses exhibited adequate item fit to all scales. Except for conduct disorder and youth-assessed separation anxiety disorder, internal (Cronbach’s α) and test-retest reliability (Pearson’s r) for scale scores were 0.70 or above. Except for youth-assessed conduct disorder, the OCHS-EBS met criteria for internal and convergent and discriminant validity. Compared with the MINI-KID, the OCHS-EBS met criteria for external convergent and discriminant validity. Conclusions: The OCHS-EBS provide reliable and valid dimensional measurement of 7 DSM-5 disorders assessed by caregivers and youth in the general population. Part II describes use of the OCHS-EBS as a categorical (present/absent) measure of disorder
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