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匹配条件: “Roger Wood” ,找到相关结果约6237条。
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Diamondback terrapin (Malaclemys terrapin terrapin) research and conservation project on the Atlantic coast of Southern New Jersey, USA
Roger Wood,Daniel McLaughlin,David Kays
Asian Journal of Conservation Biology , 2012,
Abstract:
Protocol: a highly sensitive RT-PCR method for detection and quantification of microRNAs
Erika Varkonyi-Gasic, Rongmei Wu, Marion Wood, Eric F Walton, Roger P Hellens
Plant Methods , 2007, DOI: 10.1186/1746-4811-3-12
Abstract: MicroRNAs (miRNAs) are families of short non-coding transcripts, arising from larger precursors with a characteristic hairpin secondary structure [reviewed in [1]]. Together with short interfering RNAs (siRNAs), miRNAs belong to a class of 19- to 25-nucleotide (nt) small RNAs that are essential for genome stability, development and differentiation, disease, cellular communication, signaling, and adaptive responses to biotic and abiotic stress [1-4]. A large proportion of miRNAs are highly conserved among distantly related species, from worms to mammals in the animal kingdom [1], and mosses to high flowering eudicots in plants [5,6].Currently, over 4000 miRNA sequences from vertebrates, flies, worms, plants and viruses are annotated in the Sanger Centre miRBase Database [version 9.0, October 2006; [7]]. In animals, miRNAs appear predominantly to inhibit translation by targeting partially complementary sequences located within the 3' untranslated region (UTR) of mRNA [reviewed in [8]]. The majority of animal miRNAs appear to be operating at several levels, regulating multiple targets implicated in various molecular functions and biological processes [1]. In plants, miRNAs repress gene expression by acting either on near-perfect complementary sequences in mRNA coding region to guide cleavage and translational repression [9-12], or in at least one example, on DNA to guide chromatin remodelling [13]. The majority of plant miRNA targets are developmentally important transcription factors [14,15] and stress-regulated genes [16,17]. Thus, ectopic expression of miRNAs [9,10,13,18-20] or misexpression of miRNA-resistant target mRNAs can induce strong developmental phenotypes [reviewed in [21]]. It has been proposed that plant miRNAs act mainly by clearing of the mRNA of the target regulatory genes during the cell-fate changes [15,22,23]. There is also evidence for quantitative action of plant miRNAs in quenching the target gene activity rather than eliminating it completely [
The hydrochloride salt of l-ecgonine, a congener of cocaine
Matthew R. Wood,Thomas A. Brettell,Hugh W. Thompson,Roger A. Lalancette
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808002535
Abstract: The title compound, (1R,2R,3S,5S,8S)-3-hydroxy-8-methyl-8-azoniabicyclo[3.2.1]octane-2-carboxylic acid chloride, C9H16NO3+·Cl , is both a metabolite and a precursor of the tropane alkaloid l-cocaine. The carboxyl group is not involved in dimerization, but instead donates a hydrogen bond to the chloride counter-ion, which participates in two additional hydrogen bonds. The chloride ion is thus trigonally hydrogen bonded to three l-ecgonine cations. The quarternary N proton is intramolecularly hydrogen bonded to the carboxyl C=O group, an arrangement identical to that reported for both ( )-norcocaine and the tetrachloroaurate(III) salt of l-cocaine. One close intermolecular C—H...O contact exists.
Nuclear Localization of p38 MAPK in Response to DNA Damage
C. David Wood, Tina M. Thornton, Guadalupe Sabio, Roger A. Davis, Mercedes Rincon
International Journal of Biological Sciences , 2009,
Abstract: p38 MAP kinase (MAPK) is activated in response to environmental stress, cytokines and DNA damage, and mediates death, cell differentiation and cell cycle checkpoints. The intracellular localization of p38 MAPK upon activation remains unclear, and may depend on the stimulus. We show here that activation of p38 MAPK by stimuli that induce DNA double strand breaks (DSBs), but not other stimuli, leads to its nuclear translocation. In addition, naturally occurring DSBs generated through V(D)J recombination in immature thymocytes also promote nuclear accumulation of p38 MAPK. Nuclear translocation of p38 MAPK does not require its catalytic activity, but is induced by a conformational change of p38 MAPK triggered by phosphorylation within the active site. The selective nuclear accumulation of p38 MAPK in response to DNA damage could be a mechanism to facilitate the phosphorylation of p38 MAPK nuclear targets for the induction of a G2/M cell cycle checkpoint and DNA repair.
De Novo Transcriptome Sequence Assembly and Analysis of RNA Silencing Genes of Nicotiana benthamiana
Kenlee Nakasugi, Ross N. Crowhurst, Julia Bally, Craig C. Wood, Roger P. Hellens, Peter M. Waterhouse
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059534
Abstract: Background Nicotiana benthamiana has been widely used for transient gene expression assays and as a model plant in the study of plant-microbe interactions, lipid engineering and RNA silencing pathways. Assembling the sequence of its transcriptome provides information that, in conjunction with the genome sequence, will facilitate gaining insight into the plant’s capacity for high-level transient transgene expression, generation of mobile gene silencing signals, and hyper-susceptibility to viral infection. Methodology/Results RNA-seq libraries from 9 different tissues were deep sequenced and assembled, de novo, into a representation of the transcriptome. The assembly, of16GB of sequence, yielded 237,340 contigs, clustering into 119,014 transcripts (unigenes). Between 80 and 85% of reads from all tissues could be mapped back to the full transcriptome. Approximately 63% of the unigenes exhibited a match to the Solgenomics tomato predicted proteins database. Approximately 94% of the Solgenomics N. benthamiana unigene set (16,024 sequences) matched our unigene set (119,014 sequences). Using homology searches we identified 31 homologues that are involved in RNAi-associated pathways in Arabidopsis thaliana, and show that they possess the domains characteristic of these proteins. Of these genes, the RNA dependent RNA polymerase gene, Rdr1, is transcribed but has a 72 nt insertion in exon1 that would cause premature termination of translation. Dicer-like 3 (DCL3) appears to lack both the DEAD helicase motif and second dsRNA binding motif, and DCL2 and AGO4b have unexpectedly high levels of transcription. Conclusions The assembled and annotated representation of the transcriptome and list of RNAi-associated sequences are accessible at www.benthgenome.com alongside a draft genome assembly. These genomic resources will be very useful for further study of the developmental, metabolic and defense pathways of N. benthamiana and in understanding the mechanisms behind the features which have made it such a well-used model plant.
Electrostatic charging of non-polar colloids by reverse micelles
G. Seth Roberts,Rodrigo Sanchez,Roger Kemp,Tiffany Wood,Paul Bartlett
Physics , 2007,
Abstract: Colloids dispersed in a non-polar solvent become charged when reverse micelles are added. We study the charge of individual sterically-stabilized poly(methyl methacrylate) spheres dispersed in micellar solutions of the surfactants sodium bis(2-ethyl 1-hexyl) sulfosuccinate [AOT], zirconyl 2-ethyl hexanoate [Zr(Oct)$_{2}$], and a copolymer of poly(12-hydroxystearic acid)--poly(methyl methacrylate) [PHSA-PMMA]. Although the sign of the particle charge is positive for Zr(Oct)$_{2}$, negative for AOT, and essentially neutral for PHSA-PMMA the different micellar systems display a number of common features. In particular, we demonstrate that, over a wide range of concentrations, the colloid charge is independent of the number of micelles added and scales linearly with the colloid size. A simple thermodynamic model, in which the particle charge is generated by the competitive adsorption of both positive and negative micelles, is in good agreement with the experimental data.
Which Is More Useful in Predicting Hospital Mortality -Dichotomised Blood Test Results or Actual Test Values? A Retrospective Study in Two Hospitals
Mohammed A. Mohammed, Gavin Rudge, Gordon Wood, Gary Smith, Vishal Nangalia, David Prytherch, Roger Holder, Jim Briggs
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046860
Abstract: Background Routine blood tests are an integral part of clinical medicine and in interpreting blood test results clinicians have two broad options. (1) Dichotomise the blood tests into normal/abnormal or (2) use the actual values and overlook the reference values. We refer to these as the “binary” and the “non-binary” strategy respectively. We investigate which strategy is better at predicting the risk of death in hospital based on seven routinely undertaken blood tests (albumin, creatinine, haemoglobin, potassium, sodium, urea, and white blood cell count) using tree models to implement the two strategies. Methodology A retrospective database study of emergency admissions to an acute hospital during April 2009 to March 2010, involving 10,050 emergency admissions with routine blood tests undertaken within 24 hours of admission. We compared the area under the Receiver Operating Characteristics (ROC) curve for predicting in-hospital mortality using the binary and non-binary strategy. Results The mortality rate was 6.98% (701/10050). The mean predicted risk of death in those who died was significantly (p-value <0.0001) lower using the binary strategy (risk = 0.181 95%CI: 0.193 to 0.210) versus the non-binary strategy (risk = 0.222 95%CI: 0.194 to 0.251), representing a risk difference of 28.74 deaths in the deceased patients (n = 701). The binary strategy had a significantly (p-value <0.0001) lower area under the ROC curve of 0.832 (95% CI: 0.819 to 0.845) versus the non-binary strategy (0.853 95% CI: 0.840 to 0.867). Similar results were obtained using data from another hospital. Conclusions Dichotomising routine blood test results is less accurate in predicting in-hospital mortality than using actual test values because it underestimates the risk of death in patients who died. Further research into the use of actual blood test values in clinical decision making is required especially as the infrastructure to implement this potentially promising strategy already exists in most hospitals.
Within-Mat Variability in Anatoxin-a and Homoanatoxin-a Production among Benthic Phormidium (Cyanobacteria) Strains
Susanna A. Wood,Francine M. J. Smith,Mark W. Heath,Thomas Palfroy,Sally Gaw,Roger G. Young,Ken G. Ryan
Toxins , 2012, DOI: 10.3390/toxins4100900
Abstract: Benthic Phormidium mats can contain high concentrations of the neurotoxins anatoxin-a and homoanatoxin-a. However, little is known about the co-occurrence of anatoxin-producing and non-anatoxin-producing strains within mats. There is also no data on variation in anatoxin content among toxic genotypes isolated from the same mat. In this study, 30 Phormidium strains were isolated from 1 cm2 sections of Phormidium-dominated mats collected from three different sites. Strains were grown to stationary phase and their anatoxin-a, homoanatoxin-a, dihydroanatoxin-a and dihydrohomoanatoxin-a concentrations determined using liquid chromatography-mass spectrometry. Each strain was characterized using morphological and molecular (16S rRNA gene sequences) techniques. Eighteen strains produced anatoxin-a, dihydroanatoxin-a or homoanatoxin-a. Strains isolated from each mat either all produced toxins, or were a mixture of anatoxin and non-anatoxin-producing genotypes. Based on morphology these genotypes could not be separated. The 16S rRNA gene sequence comparisons showed a difference of at least 17 nucleotides among anatoxin and non-anatoxin-producing strains and these formed two separate sub-clades during phylogenetic analysis. The total anatoxin concentration among toxic strains varied from 2.21 to 211.88 mg kg?1 (freeze dried weight), representing a 100 fold variation in toxin content. These data indicate that both the relative abundance of anatoxin and non-anatoxin-producing genotypes, and variations in anatoxin producing capability, can influence the overall toxin concentration of benthic Phormidium mat samples.
Actinidia DRM1 - An Intrinsically Disordered Protein Whose mRNA Expression Is Inversely Correlated with Spring Budbreak in Kiwifruit
Marion Wood, Georgina M. Rae, Rong-Mei Wu, Eric F. Walton, Bin Xue, Roger P. Hellens, Vladimir N. Uversky
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057354
Abstract: Intrinsically disordered proteins (IDPs) are a relatively recently defined class of proteins which, under native conditions, lack a unique tertiary structure whilst maintaining essential biological functions. Functional classification of IDPs have implicated such proteins as being involved in various physiological processes including transcription and translation regulation, signal transduction and protein modification. Actinidia DRM1 (Ade DORMANCY ASSOCIATED GENE 1), represents a robust dormancy marker whose mRNA transcript expression exhibits a strong inverse correlation with the onset of growth following periods of physiological dormancy. Bioinformatic analyses suggest that DRM1 is plant specific and highly conserved at both the nucleotide and protein levels. It is predicted to be an intrinsically disordered protein with two distinct highly conserved domains. Several Actinidia DRM1 homologues, which align into two distinct Actinidia-specific families, Type I and Type II, have been identified. No candidates for the Arabidopsis DRM1-Homologue (AtDRM2) an additional family member, has been identified in Actinidia.
The Exact Similarity between the Positron and the Electron Equations in a P and the T Violations  [PDF]
Roger Boudet
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.38101
Abstract: Using in CPT a P and T violations we show that the equation of the positron is exactly the same as the one of the electron, on the condition that both the sign of the charge and the electromagnetic potential are changed. As a consequence the velocities are both in direction to the future and the masses are both positive and, in similar experiences, the behaviours of the two particles are the same. These theoretical results are in quite agreements with the experiments of the LEP.
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