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Transcript Profiling of Different Arabidopsis thaliana Ecotypes in Response to Tobacco etch potyvirus Infection  [PDF]
José M. Cuevas,Santiago F. Elena
Frontiers in Microbiology , 2012, DOI: 10.3389/fmicb.2012.00229
Abstract: The use of high-throughput transcript profiling techniques has opened the possibility of identifying, in a single experiment, multiple host mRNAs whose levels of accumulation are altered in response to virus infection. Several studies have used this approach to analyze the response of Arabidopsis thaliana to the infection by different RNA and DNA viruses. However, the possible differences in response of genetically heterogeneous ecotypes of the plant to the same virus have never been addressed before. Here we have used a strain of Tobacco etch potyvirus (TEV) experimentally adapted to A. thaliana ecotype Ler-0 and a set of seven plant ecotypes to tackle this question. Each ecotype was inoculated with the same amount of the virus and the outcome of infection characterized phenotypically (i.e., virus infectivity, accumulation, and symptoms development). Using commercial microarrays containing probes for more than 43,000 A. thaliana transcripts, we explored the effect of viral infection on the plant transcriptome. In general, we found that ecotypes differ in the way they perceive and respond to the virus. Some ecotypes developed strong symptoms and accumulated large amounts of viral genomes, while others only developed mild symptoms and accumulated less virus. At the transcriptomic level, ecotypes could be classified into two groups according to the particular genes whose expression was altered upon infection. Moreover, a functional enrichment analyses showed that the two groups differed in the nature of the altered biological processes. For the group constituted by ecotypes developing milder symptoms and allowing for lower virus accumulation, genes involved in abiotic stresses and in the construction of new tissues tend to be up-regulated. For those ecotypes in which infection was more severe and productive, defense genes tend to be up-regulated, deviating the necessary resources from building new tissues.
The RTM Resistance to Potyviruses in Arabidopsis thaliana: Natural Variation of the RTM Genes and Evidence for the Implication of Additional Genes  [PDF]
Patrick Cosson, Valérie Schurdi-Levraud, Quang Hien Le, Ophélie Sicard, Mélodie Caballero, Fabrice Roux, Olivier Le Gall, Thierry Candresse, Frédéric Revers
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039169
Abstract: Background The non conventional RTM (Restricted Tobacco etch virus Movement) resistance which restricts long distance movement of some plant viruses in Arabidopsis thaliana is still poorly understood. Though at least three RTM genes have been identified, their precise role(s) in the process as well as whether other genes are involved needs to be elucidated. Methodology/Principal Findings In this study, the natural variation of the RTM genes was analysed at the amino acid level in relation with their functionality to restrict the long distance movement of Lettuce mosaic potyvirus (LMV). We identified non-functional RTM alleles in LMV-susceptible Arabidopsis accessions as well as some of the mutations leading to the non-functionality of the RTM proteins. Our data also indicate that more than 40% of the resistant accessions to LMV are controlled by the RTM genes. In addition, two new RTM loci were genetically identified. Conclusions/Significance Our results show that the RTM resistance seems to be a complex biological process which would involves at least five different proteins. The next challenges will be to understand how the different RTM protein domains are involved in the resistance mechanism and to characterise the new RTM genes for a better understanding of the blocking of the long distance transport of plant viruses.
Multidirectional instability of the shoulder – current concept
Seung-Ho Kim
Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology , 2009, DOI: 10.1186/1758-2555-1-12
Abstract: The multidirectional instability of the shoulder is a complex problem in terms of diagnosis and treatment. Distinct from multidirectional hyperlaxity, multidirectional instability has symptoms related with increased translations in more than one direction. Increased translation by the increased capsular ligamentous laxity is underlying pathology of the posterior and multidirectional instability. This increased capsular laxity can be in-borne or developmental and asymptomatic or minimally symptomatic initially. In this stage, attempted translation does not produce symptoms. Jerk and Kim tests reveal posterior clunk without shoulder pain [1,2].However, repetitive subluxation overloads the posteroinferior glenoid labrum by the excessive rim-loading of the humeral head. This excessive rim-loading eventually develops posteroinferior labral lesion varying from simple retroversion to incomplete detachment (Figure 1). In this stage, patient's symptom which is shoulder pain, originates from the labral lesion when the humeral head glides over the pathologic labrum. The compressive force on the torn labrum in the jerk and Kim tests generates shoulder pain. Therefore, intact labrum does not produce shoulder pain no matter how lax the glenohumeral joint is. Increased translation alone produces asymptomatic posterior clunk until the repetitive rim-loading eventually develops posteroinferior labral lesion [3].Four type of the labral lesion have been reported. The Kim lesion is a concealed and incomplete tear of the posteroinferior labrum which is characterized by loss of labral height and retroversion, marginal crack, and loose inside. The lesion is similar to the intratendinous tear of the rotator cuff in that it is not evident in the initial observation. The surgeon should be aware of the lesion and palpate with probe (Figure 2).The retroversion of the glenoid labrum decrease the containment function of the glenohumeral joint which further decrease the shoulder's stability (Figu
Differential Interactions of the Autonomous Pathway RRM Proteins and Chromatin Regulators in the Silencing of Arabidopsis Targets  [PDF]
Isabel B?urle, Caroline Dean
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002733
Abstract: We have recently shown that two proteins containing RRM-type RNA-binding domains, FCA and FPA, originally identified through their role in flowering time control in Arabidopsis, silence transposons and other repeated sequences in the Arabidopsis genome. In flowering control, FCA and FPA function in the autonomous pathway with conserved chromatin regulators, the histone demethylase FLD and the MSI1-homologue FVE, a conserved WD-repeat protein found in many chromatin complexes. Here, we investigate how the RRM proteins interact genetically with these chromatin regulators at a range of loci in the Arabidopsis genome. We also investigate their interaction with the DNA methylation pathway. In several cases the RRM protein activity at least partially required a chromatin regulator to effect silencing. However, the interactions of the autonomous pathway components differed at each target analysed, most likely determined by certain properties of the target loci and/or other silencing pathways. We speculate that the RNA-binding proteins FCA and FPA function as part of a transcriptome surveillance mechanism linking RNA recognition with chromatin silencing mechanisms.
Uni- and multidirectional wear resistance of different crosslinking degrees in UHMWPE for artificial joints  [PDF]
V.A. González-Mora, M. Hoffmann, R. Stroosnijder, E. Espinar, J.M. Llamas, M. Fernández-Fairén, F.J. Gil
Journal of Biomedical Science and Engineering (JBiSE) , 2011, DOI: 10.4236/jbise.2011.44035
Abstract: The aim of this work was to study the effect of UHMWPE crosslinking on wear performance. Differently treated UHMWPEs were studied by means of unidirectional and multidirectional wear tests. Unidirectional tests simulate total knee replacement and multidirectional tests simulate total hip replacement movements. The samples tested were observed by optical and scanning electron microscopy in order to determine wear mechanisms that explain the dif-ferent results obtained in the uni- and multidirectional wear tests performed.
Restricting exchangeable nonparametric distributions  [PDF]
Sinead Williamson,Zoubin Ghahramani,Steven N. MacEachern,Eric P. Xing
Statistics , 2012,
Abstract: Distributions over exchangeable matrices with infinitely many columns, such as the Indian buffet process, are useful in constructing nonparametric latent variable models. However, the distribution implied by such models over the number of features exhibited by each data point may be poorly- suited for many modeling tasks. In this paper, we propose a class of exchangeable nonparametric priors obtained by restricting the domain of existing models. Such models allow us to specify the distribution over the number of features per data point, and can achieve better performance on data sets where the number of features is not well-modeled by the original distribution.
Lifting and restricting recollement data  [PDF]
Pedro Nicolas,Manuel Saorin
Mathematics , 2008, DOI: 10.1007/s10485-009-9198-z
Abstract: We study the problem of lifting and restricting TTF triples (equivalently, recollement data) for a certain wide type of triangulated categories. This, together with the parametrizations of TTF triples given in "Parametrizing recollement data", allows us to show that many well-known recollements of right bounded derived categories of algebras are restrictions of recollements in the unbounded level, and leads to criteria to detect recollements of general right bounded derived categories. In particular, we give in Theorem 1 necessary and sufficient conditions for a 'right bounded' derived category of a differential graded(=dg) category to be a recollement of 'right bounded' derived categories of dg categories. In Theorem 2 we consider the particular case in which those dg categories are just ordinary algebras.
Etch-stop method for reliably fabricating sharp yet mechanically stable scanning tunneling microscope tips  [PDF]
G. Basnet,J. K. Schoelz,P. Xu,S. D. Barber,M. L. Ackerman,P. M. Thibado
Physics , 2015,
Abstract: An extension of the direct-current, double-lamella drop-off technique for electrochemically etching tungsten scanning-tunneling-microscope tips is presented. The key fabrication step introduced here is the use of an etch stop as a simple but accurate way to optimize the contact area between the etchant and the wire. By restricting the etching process, the final cone angle of the tips can be made sharp and mechanically stable without a lot of finesse from the STM tip maker.
Use of the multidirectional cat scan in visualization of an impacted tooth  [PDF]
Ana Elizabeth Aguiar da Silva,M?nica Almeida Tostes
RGO : Revista Gaúcha de Odontologia , 2009,
Abstract: Dental trauma in the anterior region of the maxilla occurs very frequently in childhood. In the majority of cases, trauma compromises the formation and eruption of anterior teeth, particularly the maxillary permanent incisors, which may lose the potential to erupt, and remain retained in the bone, originating a process known as posttraumatic impaction The treat of impaction is almost always multidisciplinary, depending on the degree of severity, and can range from a simple incision to ortho-surgical traction and requires accurate diagnosis. Conventional clinical and radiological exam constitutes the basis for primary diagnosis, but under conditions in which better visualization of the region involved is necessary, the orthodontist may require other imaging exams to safely conclude diagnosis. This study contains a clinical report of a patient, an 8-year old leukoderma boy, who presented an impacted tooth 11. Initially, by the conventional radiographic method, the option was to perform ortho-surgical traction, but tooth 11 was not fully visualized, and a multidirectional tomograph was requested, which showed evidence of the presence of accentuated root dilaceration of the tooth in question and its close relationship with the nasal fossae, making it impossible to perform orthodontic tractioning. Therefore, based on the second diagnosis, the option was to extract the tooth, perform orthodontic treatment and future prosthetic reconstruction.
GABA Regulates the Multidirectional Tangential Migration of GABAergic Interneurons in Living Neonatal Mice  [PDF]
Hiroyuki Inada, Miho Watanabe, Taku Uchida, Hitoshi Ishibashi, Hiroaki Wake, Tomomi Nemoto, Yuchio Yanagawa, Atsuo Fukuda, Junichi Nabekura
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027048
Abstract: Cortical GABAergic interneurons originate from ganglionic eminences and tangentially migrate into the cortical plate at early developmental stages. To elucidate the characteristics of this migration of GABAergic interneurons in living animals, we established an experimental design specialized for in vivo time-lapse imaging of the neocortex of neonate mice with two-photon laser-scanning microscopy. In vesicular GABA/glycine transporter (VGAT)-Venus transgenic mice from birth (P0) through P3, we observed multidirectional tangential migration of genetically-defined GABAergic interneurons in the neocortical marginal zone. The properties of this migration, such as the motility rate (distance/hr), the direction moved, and the proportion of migrating neurons to stationary neurons, did not change through P0 to P3, although the density of GABAergic neurons at the marginal zone decreased with age. Thus, the characteristics of the tangential motility of individual GABAergic neurons remained constant in development. Pharmacological block of GABAA receptors and of the Na+-K+-Cl? cotransporters, and chelating intracellular Ca2+, all significantly reduced the motility rate in vivo. The motility rate and GABA content within the cortex of neonatal VGAT-Venus transgenic mice were significantly greater than those of GAD67-GFP knock-in mice, suggesting that extracellular GABA concentration could facilitate the multidirectional tangential migration. Indeed, diazepam applied to GAD67-GFP mice increased the motility rate substantially. In an in vitro neocortical slice preparation, we confirmed that GABA induced a NKCC sensitive depolarization of GABAergic interneurons in VGAT-Venus mice at P0-P3. Thus, activation of GABAAR by ambient GABA depolarizes GABAergic interneurons, leading to an acceleration of their multidirectional motility in vivo.
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