Identification of host genes potentially implicated in the Malus pumila and ‘Candidatus Phytoplasma mali’ interactions

Two‘Candidatus Phytoplasma mali’ strains (AP and AT), were studied in experimentally infected apple trees to analyze transcriptional profiles during interaction with phytoplasmas. Three groups of sample combinations were employed: healthy - infected, symptomatic - non-symptomatic, and AP-infected - AT-infected sample. The majority of genes were differently expressed between healthy and infected samples. Changes in gene expression involved a wide spectrum of biological functions, including processes of metabolism, cell defence, photosynthesis, transport, transcription, signal transduction and protein synthesis. The possible effect of phytoplasma infection on these processes and their relationships with disease development, symptom appearance and possible plant defence system is discussed. Keywords: Apple, phytoplasmas, ‘Ca. P. mali’, gene expression, transcriptom

Early and late follow-up of untreated traumatic aortic lesion: a support to delayed surgery

Fuente Fuente, Carlos;Montes Gil, Antonio;Periel Piquer, Montserra

Molecular modeling of a tandem two pore domain potassium channel reveals a putative binding Site for general anesthetics

[Image: see text] Anesthetics are thought to mediate a portion of their activity via binding to and modulation of potassium channels. In particular, tandem pore potassium channels (K2P) are transmembrane ion channels whose current is modulated by the presence of general anesthetics and whose genetic absence has been shown to confer a level of anesthetic resistance. While the exact molecular structure of all K2P forms remains unknown, significant progress has been made toward understanding their structure and interactions with anesthetics via the methods of molecular modeling, coupled with the recently released higher resolution structures of homologous potassium channels to act as templates. Such models reveal the convergence of amino acid regions that are known to modulate anesthetic activity onto a common three- dimensional cavity that forms a putative anesthetic binding site. The model successfully predicts additional important residues that are also involved in the putative binding site as validated by the results of suggested experimental mutations. Such a model can now be used to further predict other amino acid residues that may be intimately involved in the target-based structure–activity relationships that are necessary for anesthetic binding

The Location and Nature of General Anesthetic Binding Sites on the Active Conformation of Firefly Luciferase; A Time Resolved Photolabeling Study

Firefly luciferase is one of the few soluble proteins that is acted upon by a wide variety of general anesthetics and alcohols; they inhibit the ATP–driven production of light. We have used time–resolved photolabeling to locate the binding sites of alcohols during the initial light output, some 200 ms after adding ATP. The photolabel 3-azioctanol inhibited the initial light output with an IC50 of 200 µM, close to its general anesthetic potency. Photoincorporation of [3H]3-azioctanol into luciferase was saturable but weak. It was enhanced 200 ms after adding ATP but was negligible minutes later. Sequencing of tryptic digests by HPLC–MSMS revealed a similar conformation–dependence for photoincorporation of 3-azioctanol into Glu-313, a residue that lines the bottom of a deep cleft (vestibule) whose outer end binds luciferin. An aromatic diazirine analog of benzyl alcohol with broader side chain reactivity reported two sites. First, it photolabeled two residues in the vestibule, Ser-286 and Ile-288, both of which are implicated with Glu-313 in the conformation change accompanying activation. Second, it photolabeled two residues that contact luciferin, Ser-316 and Ser-349. Thus, time resolved photolabeling supports two mechanisms of action. First, an allosteric one, in which anesthetics bind in the vestibule displacing water molecules that are thought to be involved in light output. Second, a competitive one, in which anesthetics bind isosterically with luciferin. This work provides structural evidence that supports the competitive and allosteric actions previously characterized by kinetic studies

Recognition of Anesthetic Barbiturates by a Protein Binding Site: A High Resolution Structural Analysis

Barbiturates potentiate GABA actions at the GABAA receptor and act as central nervous system depressants that can induce effects ranging from sedation to general anesthesia. No structural information has been available about how barbiturates are recognized by their protein targets. For this reason, we tested whether these drugs were able to bind specifically to horse spleen apoferritin, a model protein that has previously been shown to bind many anesthetic agents with affinities that are closely correlated with anesthetic potency. Thiopental, pentobarbital, and phenobarbital were all found to bind to apoferritin with affinities ranging from 10–500 µM, approximately matching the concentrations required to produce anesthetic and GABAergic responses. X-ray crystal structures were determined for the complexes of apoferritin with thiopental and pentobarbital at resolutions of 1.9 and 2.0 Å, respectively. These structures reveal that the barbiturates bind to a cavity in the apoferritin shell that also binds haloalkanes, halogenated ethers, and propofol. Unlike these other general anesthetics, however, which rely entirely upon van der Waals interactions and the hydrophobic effect for recognition, the barbiturates are recognized in the apoferritin site using a mixture of both polar and nonpolar interactions. These results suggest that any protein binding site that is able to recognize and respond to the chemically and structurally diverse set of compounds used as general anesthetics is likely to include a versatile mixture of both polar and hydrophobic elements

Grapevine yellows diseases in Spain: eight year survey of disease spread and molecular characterization of phytoplasmas involved

7 páginas, 4 figuras, 2 tablas.[EN] Among grapevine yellows phytoplasma diseases in Europe, flavescence dorée (FD) is the most devastating and in the last decade has reached Spanish vineyards, mainly in Catalonia. An eight-year survey was carried out in the areas where the disease has spread (Alt Empordà, Catalonia, Northern Spain) and in the remaining vine-growing areas of Catalonia. Sequence analyses of a portion of the 16S-23S ribosomal DNA cistron, from selected grapevine samples from Catalonia, showed that the phytoplasmas involved in grapevine yellows belong to 16S ribosomal subgroups V-D (flavescence dorée, FD) and XII-A (bois noir, BN). A set of Spanish FD isolates collected during these years were further studied by RFLP analyses of the 16S-23S ribosomal DNA fragment, as well as the rpS3 and SecY genes. All the FD phytoplasma strains studied were related to phytoplasmas belonging to ribosomal protein subgroup rp-E.[ES] La flavescencia dorada (FD) es la enfermedad más agresiva de entre todas las enfermedades de fitoplasmas que causan amarilleos de vid en Europa, y que en la última década ha alcanzado también a los viñedos de España, principalmente en Cataluña. Se ha realizado un seguimiento durante ocho años en las zonas donde la enfermedad se había difundido (Alt Empordà, Cataluña) y en el resto de zonas con cultivo de vid de Cataluña. El análisis del fragmento del gen DNA ribosomal 16S-23S, de una selección de muestras de vides de Cataluña, indica que los fitoplasmas que están implicados en los amarilleos de vid pertenecen a los subgrupos ribosomales 16S V-D (flavescencia dorada, FD) y XII-A (bois noir, BN). Una selección de aislados españoles de FD obtenidos durante estos años se ha examinado mediante análisis RFLP del fragmento del gen ribosomal 16S-23S, y de los genes rpS3 y SecY. Todos los aislamientos de fitoplasmas FD estudiados están relacionados con fitoplasmas pertenecientes al subgrupo de proteína ribosomal rp-E.This work was partially supported by a FEOGA grant (number FEDER: 94 00 10 038).Peer reviewe