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Search Results: 1 - 10 of 3087 matches for " Caitilyn Allen "
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Ralstonia solanacearum Extracellular Polysaccharide Is a Specific Elicitor of Defense Responses in Wilt-Resistant Tomato Plants
Annett Milling,Lavanya Babujee,Caitilyn Allen
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015853
Abstract: Ralstonia solanacearum, which causes bacterial wilt of diverse plants, produces copious extracellular polysaccharide (EPS), a major virulence factor. The function of EPS in wilt disease is uncertain. Leading hypotheses are that EPS physically obstructs plant water transport, or that EPS cloaks the bacterium from host plant recognition and subsequent defense. Tomato plants infected with R. solanacearum race 3 biovar 2 strain UW551 and tropical strain GMI1000 upregulated genes in both the ethylene (ET) and salicylic acid (SA) defense signal transduction pathways. The horizontally wilt-resistant tomato line Hawaii7996 activated expression of these defense genes faster and to a greater degree in response to R. solanacearum infection than did susceptible cultivar Bonny Best. However, EPS played different roles in resistant and susceptible host responses to R. solanacearum. In susceptible plants the wild-type and eps? mutant strains induced generally similar defense responses. But in resistant Hawaii7996 tomato plants, the wild-type pathogens induced significantly greater defense responses than the eps? mutants, suggesting that the resistant host recognizes R. solanacearum EPS. Consistent with this idea, purified EPS triggered significant SA pathway defense gene expression in resistant, but not in susceptible, tomato plants. In addition, the eps? mutant triggered noticeably less production of defense-associated reactive oxygen species in resistant tomato stems and leaves, despite attaining similar cell densities in planta. Collectively, these data suggest that bacterial wilt-resistant plants can specifically recognize EPS from R. solanacearum.
Ralstonia syzygii, the Blood Disease Bacterium and Some Asian R. solanacearum Strains Form a Single Genomic Species Despite Divergent Lifestyles
Beno?t Remenant, Jean-Charles de Cambiaire, Gilles Cellier, Jonathan M. Jacobs, Sophie Mangenot, Valérie Barbe, Aurélie Lajus, David Vallenet, Claudine Medigue, Mark Fegan, Caitilyn Allen, Philippe Prior
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024356
Abstract: The Ralstonia solanacearum species complex includes R. solanacearum, R. syzygii, and the Blood Disease Bacterium (BDB). All colonize plant xylem vessels and cause wilt diseases, but with significant biological differences. R. solanacearum is a soilborne bacterium that infects the roots of a broad range of plants. R. syzygii causes Sumatra disease of clove trees and is actively transmitted by cercopoid insects. BDB is also pathogenic to a single host, banana, and is transmitted by pollinating insects.?Sequencing and DNA-DNA hybridization studies indicated that despite their phenotypic differences, these three plant pathogens are actually very closely related, falling into the Phylotype IV subgroup of the R. solanacearum species complex. To better understand the relationships among these bacteria, we sequenced and annotated the genomes of R. syzygii strain R24 and BDB strain R229. These genomes were compared to strain PSI07, a closely related Phylotype IV tomato isolate of R. solanacearum, and to five additional R. solanacearum genomes. Whole-genome comparisons confirmed previous phylogenetic results: the three phylotype IV strains share more and larger syntenic regions with each other than with other R. solanacearum strains. Furthermore, the genetic distances between strains, assessed by an in-silico equivalent of DNA-DNA hybridization, unambiguously showed that phylotype IV strains of BDB, R. syzygii and R. solanacearum form one genomic species. Based on these comprehensive data we propose a revision of the taxonomy of the R. solanacearum species complex. The BDB and R. syzygii genomes encoded no obvious unique metabolic capacities and contained no evidence of horizontal gene transfer from bacteria occupying similar niches. Genes specific to R. syzygii and BDB were almost all of unknown function or extrachromosomal origin. Thus, the pathogenic life-styles of these organisms are more probably due to ecological adaptation and genomic convergence during vertical evolution than to the acquisition of DNA by horizontal transfer.
Genomes of three tomato pathogens within the Ralstonia solanacearum species complex reveal significant evolutionary divergence
Beno?t Remenant, Bénédicte Coupat-Goutaland, Alice Guidot, Gilles Cellier, Emmanuel Wicker, Caitilyn Allen, Mark Fegan, Olivier Pruvost, Mounira Elbaz, Alexandra Calteau, Gregory Salvignol, Damien Mornico, Sophie Mangenot, Valérie Barbe, Claudine Médigue, Philippe Prior
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-379
Abstract: The genomes of three tomato bacterial wilt pathogens, CFBP2957 (phy. IIA), CMR15 (phy. III) and PSI07 (phy. IV) were sequenced and manually annotated. These genomes were compared with those of three previously sequenced R. solanacearum strains: GMI1000 (tomato, phy. I), IPO1609 (potato, phy. IIB), and Molk2 (banana, phy. IIB). The major genomic features (size, G+C content, number of genes) were conserved across all of the six sequenced strains. Despite relatively high genetic distances (calculated from average nucleotide identity) and many genomic rearrangements, more than 60% of the genes of the megaplasmid and 70% of those on the chromosome are syntenic. The three new genomic sequences revealed the presence of several previously unknown traits, probably acquired by horizontal transfers, within the genomes of R. solanacearum, including a type IV secretion system, a rhi-type anti-mitotic toxin and two small plasmids. Genes involved in virulence appear to be evolving at a faster rate than the genome as a whole.Comparative analysis of genome sequences and gene content confirmed the differentiation of R. solanacearum species complex strains into four phylotypes. Genetic distances between strains, in conjunction with CGH analysis of a larger set of strains, revealed differences great enough to consider reclassification of the R. solanacearum species complex into three species. The data are still too fragmentary to link genomic classification and phenotypes, but these new genome sequences identify a pan-genome more representative of the diversity in the R. solanancearum species complex.The rapidly accumulating complete genomes in databases provide unique opportunities to study relationships among organisms. Since DNA sequences are conserved between closely related organisms, comparative genomic analyses are a powerful tool for understanding the complex evolutionary events in specific phylogenetic lineages.R. solanacearum, formerly known as Pseudomonas solanacearum and Bu
Dark Experiments: From Black Holes to Cosmic Rays  [PDF]
Allen D. Allen
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.39125
Abstract: Some nagging questions in modern physics can be resolved rigorously using a basic mathematical formalism, albeit with the need to admit that non-isomorphic realities arise to various degrees in a given universe. Let U=(m', m\") be an unordered pair of distinct massive objects in different reference frames. A dark experiment is an ordering u, mv> of the elements of U, either or, exclusively, , where the left-hand member of the ordered pair is called the observer, and where there exists a 1-to-1 mapping f:{u}→{events}, mv> , such that both elements of an ordered pair in a dark experiment agree on the events that unfold in the experiment. However, since , it follows that f()≠f(). This describes non-isomorphic realities where in both elements of each ordered pair mapping two distinct sets of unfolding events will agree on their respective events. Consequently, there is an inherent limitation on what can be determined directly from experimentation. Examples arise in the context of the Hawking information paradox, relativistic time travel, and cosmic ray experiments.
State of the Art in Cardiac Intervention: A Case Report  [PDF]
Allen D. Allen
International Journal of Clinical Medicine (IJCM) , 2012, DOI: 10.4236/ijcm.2012.37112

The first acute myocardial infarction (MI) of an elderly male was determined through angiography to be due to an infarct of the circumflex artery. The angiogram also revealed chronic occlusion and diffuse disease of the left anterior descending artery (LAD). This had been compensated for by collateral circulation from the right coronary artery. Since the patient had no prior history of coronary artery disease, the chronic and collateralized disease of the LAD was presumed to be stable and this artery was not treated. Due to a history of aspirin intolerance a bare metal stent was implanted in the circumflex artery. Within hours after stenting the patient had a second acute MI. Despite no change in the angiogram, the EKG suggested that the LAD was the source of the second MI. Indeed, a drug-eluting stent implanted in the LAD resolved the patient’s signs and symptoms and he was discharged with a favorable outcome. The surprising second MI and the inconsistent stenting illustrate that when the unexpected occurs, there is no substitute for the judgment of a skilled clinician.

Finite Gravity: From the Big Bang to Dark Matter  [PDF]
Allen D. Allen
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.32020

The purpose of the present paper is to assume that the expanding spacetime of our cosmos was created by the big bang. It then follows that there exists a finite instantaneous radial extent dRU to spacetime as observed from anywhere in spacetime by comoving observers. The consequences for gravity are explored by first considering the scalar field of a central mass that defines the dynamic properties of a circular orbit for each radius RdRU under the postulate of weak equivalence. These properties include an orbital velocity and an escape velocity. For a central mass of galactic proportion, the escape velocity becomes large even at cosmological distances. By considering the dynamics of a smaller mass occupying the last orbit, we find that the established laws of physics lead to different rotation curves than they do when applied to the solar system. Since galactic rotation curves reveal the existence of dark matter, this is anticipated to have some consequences for our understanding of dark matter.

Implications of rare neurological disorders and perceptual errors in natural and synthetic consciousness  [PDF]
Allen D. Allen
World Journal of Neuroscience (WJNS) , 2013, DOI: 10.4236/wjns.2013.34031

Recent theories on natural and synthetic consciousness overlook the geometric structure necessary for awareness of 3-dimensional space, as strikingly illustrated by left-neglect disorder. Furthermore, awareness of 3-dimensional space entails some surprisingly tenacious optical illusions, as demonstrated by an experiment in the text. Awareness of linear time is also crucial and complex. As a consequence, synthetic consciousness cannot be realized by simply intercomnecting a large number of electronic circuits constructed from ordinary chips and transistors. Since consciousness is a subjective experience, there is no sufficient condition for consciousness that can be experimentally confirmed. The most we can hope for is agreement on the necessary conditions for consciousness. Toward that end, this paper reviews some relevant clinical phenomena. 

Mortality and morbidity due to the failure to treat mild anemia unrelated to cancer in elderly Americans—Review of the literature and case presentation  [PDF]
Allen D. Allen
Advances in Aging Research (AAR) , 2013, DOI: 10.4236/aar.2013.24022
Abstract: Even mild iron deficiency anemia, as defined by the World Health Organization, is associated with increased mortality and significant morbidity in elderly individuals who are cancer free. Yet, anemia in the elderly is often dismissed as a benign sign of aging. This problem is exacerbated by the fact that elderly individuals often suffer from gastrointestinal complaints that preclude treatment with iron supplements by mouth. The FDA has approved two brands of injectable iron for treating such patients. Nonetheless, a major American health maintenance organization refuses to treat elderly patients with injectable iron, even when it is indicated, unless their anemia is associated with cancer. This may well reflect a public health crisis afflicting many elderly residents of the United States.
Self-Contradictions from the Excessive Use of Natural Units  [PDF]
Allen D. Allen
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.56049

The hypothesis c = h = G = 1 implies that unit mass is not a single-valued function but rather has two widely varying values, such as 7.4 × 10-51 kg and 4.0 × 1035 kg. Hence, the considerable body of work in theoretical physics that uses this common convention must be deemed suspect. In order to avoid this problem, theoreticians must limit themselves to c = h = 1 or, exclusively, c = G = 1 depending upon whether they are chiefly concerned with atomic physics or with gravity, respectively.

Quantum Effects from a Simple Card Game  [PDF]
Allen D. Allen
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.518195
Abstract: A well-known, classical conundrum, which is related to conditional probability, has heretofore only been used for games and puzzles. It is shown here, both empirically and formally, that the counterintuitive phenomenon in question has consequences that are far more profound, especially for physics. A simple card game the reader can play at home demonstrates the counterintuitive phenomenon, and shows how it gives rise to hidden variables. These variables are “hidden” in the sense that they belong to the past and no longer exist. A formal proof shows that the results are due to the duration of what can be thought of as a gambler’s bet, without loss of generalization. The bet is over when it is won or lost, analogous to the collapse of a wave function. In the meantime, new and empowering information does not change the original probabilities. A related thought experiment involving a pregnant woman demonstrates that macroscopic systems do not always have states that are completely intrinsic. Rather, the state of a macroscopic system may depend upon how the experiment is set up and how the system is measured even though no wave functions are involved. This obviously mitigates the chasm between the quantum mechanical and the classical.
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