7 results on '"Richard, Abbott"'
Search Results
2. Phylogenomic inferencein extremis: A case study with mycoheterotroph plastomes
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Sean W. Graham, Vincent S. F. T. Merckx, Gwynne S. Lim, Kurt M. Neubig, Marybel Soto Gomez, Hayley Darby, Tomohisa Yukawa, J. Richard Abbott, Gemma E. Beatty, Vivienne K. Y. Lam, and Jim Provan
- Subjects
0106 biological sciences ,0301 basic medicine ,Burmanniaceae ,DNA, Plant ,Genome, Plastid ,Plant Science ,Biology ,Genes, Plant ,010603 evolutionary biology ,01 natural sciences ,Genome ,Evolution, Molecular ,Magnoliopsida ,03 medical and health sciences ,Dioscoreales ,Genetics ,Amino Acids ,Photosynthesis ,Orchidaceae ,Phylogeny ,Ecology, Evolution, Behavior and Systematics ,Plant Proteins ,2. Zero hunger ,Long branch attraction ,Models, Genetic ,Phylogenetic tree ,Corsiaceae ,Fungi ,Heterotrophic Processes ,Genomics ,Gentianaceae ,15. Life on land ,Thismiaceae ,biology.organism_classification ,Biological Evolution ,Petrosaviaceae ,030104 developmental biology ,Evolutionary biology ,Ericaceae ,Genome, Plant - Abstract
Premise of the study Phylogenomic studies employing large numbers of genes, including those based on plastid genomes (plastomes), are becoming common. Nonphotosynthetic plants such as mycoheterotrophs (which rely on root-associated fungi for essential nutrients, including carbon) tend to have highly elevated rates of plastome evolution, substantial genome reduction, or both. Mycoheterotroph plastomes therefore provide excellent test cases for investigating how extreme conditions impact phylogenomic inference. Methods We used parsimony and likelihood analysis of protein-coding gene sets from published and newly completed plastomes to infer the phylogenetic placement of taxa from the 10 angiosperm families in which mycoheterotrophy evolved. Key results Despite multiple very long branches that reflect elevated substitution rates, and frequently patchy gene recovery due to genome reduction, inferred phylogenetic placements of most mycoheterotrophic lineages in DNA-based likelihood analyses are both well supported and congruent with other studies. Amino-acid-based likelihood placements are broadly consistent with DNA-based inferences, but extremely rate-elevated taxa can have unexpected placements-albeit with weak support. In contrast, parsimony analysis is strongly misled by long-branch attraction among many distantly related mycoheterotrophic monocots. Conclusions Mycoheterotrophic plastomes provide challenging cases for phylogenomic inference, as substitutional rates can be elevated and genome reduction can lead to sparse gene recovery. Nonetheless, diverse likelihood frameworks provide generally well-supported and mutually concordant phylogenetic placements of mycoheterotrophs, consistent with recent phylogenetic studies and angiosperm-wide classifications. Previous predictions of parallel photosynthesis loss within families are supported for Burmanniaceae, Ericaceae, Gentianaceae, and Orchidaceae. Burmanniaceae and Thismiaceae should not be combined as a single family in Dioscoreales.
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- 2018
3. (2627) Proposal to conserve the name Senega against Senegaria, Anthallogea, Corymbula, Leptrochia, Pylostachya, and Sexilia (Polygalaceae)
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John McNeill, Michelle Mota, J. Richard Abbott, and José Floriano Barêa Pastore
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0106 biological sciences ,0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,biology ,Traditional medicine ,Polygalaceae ,Plant Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Ecology, Evolution, Behavior and Systematics - Published
- 2018
4. The use of a membrane filtration device to form dried plasma spots for the quantitative determination of guanfacine in whole blood
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Jack Henion, Phillip Wang, Yuanyuan Li, and Richard Abbott
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Analyte ,Bioanalysis ,Chromatography ,medicine.diagnostic_test ,Chemistry ,Elution ,Organic Chemistry ,Analytical chemistry ,Hematocrit ,Tandem mass spectrometry ,Analytical Chemistry ,Standard curve ,medicine ,Sample preparation ,Spectroscopy ,Whole blood - Abstract
RATIONALE A two-layered polymeric membrane is employed for the formation of separated dried plasma spots from whole blood as an alternative to the direct analysis of whole dried blood spots (DBS). This dried plasma spot (DPS) analysis procedure precludes potential issues of hematocrit differences in whole blood samples while providing pharmokinetic data from plasma rather than whole blood. The described procedure is also semi-automated thus providing a simpler work flow for LC/MS/MS bioanalysis procedures. METHODS Molecular filtration of red blood cells (RBC) from applied microsamples of whole blood fortified with guanfacine and its stable isotope internal standard was accomplished with a two-layer polymeric membrane substrate. The lower membrane surface containing the separated plasma spot was physically separated from the upper membrane followed by semi-automated direct elution of the sample to an online solid-phase extraction (SPE) cartridge followed by liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). RESULTS A two-layer membrane sample preparation substrate produced plasma from whole blood without centrifugation which could be directly eluted for semi-automated LC/MS/MS bioanalysis. Standard curves were constructed by plotting peak area ratios between the analyte and the stable isotope labeled internal standard (SIL-IS) versus the nominal concentration in whole blood. A weighted 1/x2 linear regression was applied to the data from DPS samples. Standard curves were linear over the range 0.25–250 ng/mL human whole blood. The representative regression equation was y = 0.0142x + 0.00248 (R2 = 0.995) for the described DPS assay. CONCLUSIONS The described work demonstrates proof-of-principle using membrane sample preparation techniques to form DPS samples from whole blood for subsequent bioanalysis by LC/MS/MS. This approach has the potential to eliminate the hematocrit issues from the current controversy surrounding validation of DBS assays. Copyright © 2012 John Wiley & Sons, Ltd.
- Published
- 2012
5. Primer development for the plastid region ycf1 in Annonaceae and other magnoliids
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J. Richard Abbott and Kurt M. Neubig
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biology ,Phylogenetic tree ,Laurales ,Plant Science ,biology.organism_classification ,Magnoliales ,Piperales ,Magnoliids ,Annonaceae ,Evolutionary biology ,Phylogenetics ,Botany ,Genetics ,Canellales ,Ecology, Evolution, Behavior and Systematics - Abstract
UNLABELLED PREMISE OF THE STUDY Primers were developed for a portion of the ycf1 plastid gene in magnoliid taxa to investigate the utility of ycf1 in phylogenetic analyses. • METHODS AND RESULTS Twenty-six species across six families within the magnoliid group (Canellales, Piperales, Laurales, and Magnoliales) were sampled to examine the ability to amplify ycf1. Additionally, 29 accessions of Asimina and Deeringothamnus (Annonaceae) were sequenced to assess levels of variation in ycf1 compared to matK and trnL-F. • CONCLUSIONS Results indicate that ycf1 is easily amplified and sequenced. In Annonaceae, ycf1 provides more informative phylogenetic characters than commonly used markers such as matK and trnL-F.
- Published
- 2010
6. Pharmacokinetics and tolerability of lamotrigine and olanzapine coadministered to healthy subjects
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Sarah Job, Jonathan Bullman, John A. Ascher, Jagdev Sidhu, Richard Abbott, Emma Francis, and Jochen G W Theis
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Pharmacology ,Olanzapine ,business.industry ,medicine.drug_class ,medicine.medical_treatment ,Dopamine antagonist ,Atypical antipsychotic ,Lamotrigine ,Placebo ,Anticonvulsant ,Pharmacokinetics ,Tolerability ,Anesthesia ,Medicine ,Pharmacology (medical) ,business ,medicine.drug - Abstract
Aim To assess the pharmacokinetic effect and tolerability of lamotrigine 200 mg day−1 and olanzapine 15 mg day−1 coadministration in healthy male volunteers. Methods Subjects were randomized to receive either lamotrigine titrated on days 1–42 with olanzapine added on days 43–56 (LTG + OLZ group; N = 16), lamotrigine titration with placebo added on days 43–56 (LTG group; N = 12), or placebo on days 1–42 with olanzapine added on days 43–56 (OLZ group; N = 16). Steady state (0–24 h) pharmacokinetic profiles were determined on day 56 in each group. Results The average (90% confidence interval) ratios of lamotrigine area under the concentration–time curve from 0 to 24 h and maximum observed concentration for the comparison of LTG + OLZ:LTG were 0.76 (0.65, 0.90) and 0.80 (0.71, 0.90), respectively. Olanzapine pharmacokinetics were essentially unaffected by lamotrigine. The most frequently reported adverse events (AEs) during combination therapy were fatigue, dizziness and mild transaminase elevations. These AEs occurred at similar frequencies in the LTG + OLZ and OLZ cohorts, while being less frequent or absent in the LTG group. Conclusions Lamotrigine and olanzapine coadministration in patients who may benefit from the combination was supported by this study. Lamotrigine dosing schedules are recommended to remain unchanged when combined with olanzapine therapy. However, the possibility exists that the lamotrigine dose for some patients may need adjustment to optimize treatment when olanzapine is added to or withdrawn from a regimen including lamotrigine.
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- 2006
7. Plant Systematics: A Phylogenetic Approach
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Rudolf Schmid, Walter S. Judd, Christopher S. Campbell, Elizabeth A. Kellogg, Peter F. Stevens, Michael J. Donoghue, Daniel L. Nickrent, Kenneth R. Robertson, J. Richard Abbott, and Barbara S. Carlsward
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Systematics ,Phylogenetic tree ,Evolutionary biology ,Plant Science ,Biology ,Ecology, Evolution, Behavior and Systematics - Published
- 2007
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