1,721,010 research outputs found
Costrutti esprimenti recettori chimerici, e loro uso per l'attivazione controllata delle risposte di difesa a organismi patogeni in piante.
No full textLa presente invenzione riguarda la costruzione e l’utilizzo in piante di geni chimerici che permettono l’attivazione controllata delle risposte di difesa a organismi patogeni. L’invenzione trova applicazione nel settore agro-industriale
Proteomic complex detection using sedimentation
No full textProtein-protein interactions are important in many cellular processes, but there are still relatively few methods to screen for novel protein complexes. Here we present a quantitative proteomics technique called ProCoDeS (Proteomic Complex Detection using Sedimentation) for profiling the sedimentation of a large number of proteins through a rate zonal centrifugation gradient. Proteins in a putative complex can be identified since they sediment faster than predicted from their monomer molecular weight. Using solubilized mitochondrial membrane proteins from Arabidopsis thaliana, the relative protein abundance in fractions of a rate zonal gradient was measured with the isotopic labeling reagent ICAT and electrospray mass spectrometry. Subunits of the same protein complex had very similar gradient distribution profiles, demonstrating the reproducibility of the quantitation method. The approximate size of the unknown complex can be inferred from its sedimentation rate relative to known protein complexes. ProCoDeS will be of use in screening extracts of tissues, cells, or organelle fractions to identify specific proteins in stable complexes that can be characterized by subsequent targeted techniques such as affinity tagging
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Oligogalacturonide-auxin antagonism does not require post-transcriptional gene silencing or stabilization of auxin response repressors in Arabidopsis
Full text linkAlpha 1-4-linked oligogalacturonides (OGs) derived from plant cell walls are a class of damageassociated
molecular patterns (DAMPs) and well-known elicitors of the plant immune response.
Early transcript changes induced by OGs largely overlap those induced by flg22, a peptide derived
from bacterial flagellin, a well-characterized microbe-associated molecular pattern (MAMP),
although responses diverge over time. OGs also regulate growth and development of plant cells and
organs, due to an auxin-antagonistic activity. The molecular basis of this antagonism is still
unknown. Here we show that, in Arabidopsis, OGs inhibit adventitious root formation induced by
auxin in leaf explants as well as the expression of several auxin-responsive genes. Genetic,
biochemical and pharmacological experiments indicate that inhibition of auxin responses by OGs
does not require ethylene, jasmonic acid and salicylic acid signaling and is independent of
AtrbohD-mediated ROS production. Free IAA levels are not noticeably altered by OGs. Notably,
OG- as well as flg22-auxin antagonism does not involve any of the following mechanisms: i)
stabilization of auxin-response repressors; ii) decreased levels of auxin receptor transcripts through
the action of microRNAs. Our results suggest that OGs and flg22 antagonize auxin responses
independently of Aux/IAA repressor stabilization and of post-transcriptional gene silencing
Oligogalacturonides regulate plant defense and development by antagonizing auxin signalling
No full textConstitutive expression of a fungal endo-polygalacturonase increases plant resistance to pathogens and alters the auxin percepetion
No full textAn interaction network mediated by the oligogalacturonides receptor WAK1 regulates local response to wounding in Arabidopsis
No full textThe polygalacturonase-inhibiting protein PGIP2 of Phaseolus vulgaris has evolved a mixed mode of inhibition of endopolygalacturonase PG1 of Botrytis cinerea
Full text linkBotrytis cinerea is a phytopathogenic fungus that causes gray mold in > 1,000 plant species. During infection, it secretes several endopolygalacturonases (PGs) to degrade cell wall pectin, and among them, BcPG1 is constitutively expressed and is an important virulence factor. To counteract the action of PGs, plants express polygalacturonase-inhibiting proteins (PGIPs) that have been shown to inhibit a variety of PGs with different inhibition kinetics, both competitive and noncompetitive. The PG-PGIP interaction promotes the accumulation of oligogalacturonides, fragments of the plant cell wall that are general elicitors of plant defense responses. Here, we characterize the enzymatic activity of BcPG1 and investigate its interaction with PGIP isoform 2 from Phaseolus vulgaris (PvPGIP2) by means of inhibition assays, homology modeling, and molecular docking simulations. Our results indicate a mixed mode of inhibition. This is compatible with a model for the interaction where PvPGIP2 binds the N-terminal portion of BcPG1, partially covering its active site and decreasing the enzyme affinity for the substrate. The structural framework provided by the docking model is confirmed by site-directed mutagenesis of the residues that distinguish PvPGIP2 from the isoform PvPGIP1. The finding that PvPGIP2 inhibits BcPG1 with a mixed-type kinetics further indicates the versatility of PGIPs to evolve different recognition specificities
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