781 research outputs found

    Activation of the Pathogen-Inducible Gst1 Promoter of Potato after Elicitation by Venturia inaequalis and Erwinia amylovora in Transgenic Apple ( Malus × Domestica )

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    Rather than using a constitutive promoter to drive transgenes for resistance against fungal and bacterial diseases in genetic engineering of apple (Malus × domestica) cultivars, a promoter induced only after infection was preferred. The ability of the Pgst1 promoter from potato (Solanum tuberosum L.) to drive expression of the gusA reporter gene was determined in two genotypes of apple: the fruit cultivar Royal Gala and the M.26 rootstock. β-glucuronidase activity in the transgenic lines grown in a growth chamber was determined quantitatively using fluorometric assays and compared to the activity in Cauliflower Mosaic Virus (CaMV) 35S promoter-driven transgenic lines. In both apple genotypes, the Pgst1 promoter exhibited a low level of expression after bacterial and fungal inoculation compared to the level obtained with the PCaMV35S promoter (15% and 8% respectively). The Pgst1 promoter was systematically activated in apple at the site of infection with a fungal pathogen. It was also activated after treatment with salicylic acid, but not after wounding. Taken together, these data show that, although the Pgst1 promoter is less active than the PCaMV35S promoter in apple, its pathogen responsiveness could be useful in driving the expression of transgenes to promote bacterial and fungal disease resistanc

    E2F Activation of S Phase Promoters via Association with HCF-1 and the MLL Family of Histone H3K4 Methyltransferases

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    E2F transcriptional regulators control human-cell proliferation by repressing and activating the transcription of genes required for cell-cycle progression, particularly the S phase. E2F proteins repress transcription in association with retinoblastoma pocket proteins, but less is known about how they activate transcription. Here, we show that the human G1 phase regulator HCF-1 associates with both activator (E2F1 and E2F3a) and repressor (E2F4) E2F proteins, properties that are conserved in insect cells. Human HCF-1-E2F interactions are versatile: their associations and binding to E2F-responsive promoters are cell-cycle selective, and HCF-1 displays coactivator properties when bound to the E2F1 activator and corepressor properties when bound to the E2F4 repressor. During the G1-to-S phase transition, HCF-1 recruits the mixed-lineage leukemia (MLL) and Set-1 histone H3 lysine 4 methyltransferases to E2F-responsive promoters and induces histone methylation and transcriptional activation. These results suggest that HCF-1 induces cell-cycle-specific transcriptional activation by E2F proteins to promote cell proliferation

    57. Physical and dosimetric aspects of quality assurance in stereotactic radiotherapy

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    A quality assurance system in stereotactic radiosurgery and stereotactic fractionated radiotherapy, concerning the physical and dosimetric aspects, may be divided into three elements: (1) the preparation of reliable basic data for the computerized treatment planning system; (2) a control of the accelerator parameters prior to patient treatment; (3) preparation of the optimal treatment plan with the treatment planning system.Due to the small size of the beams formed by circular collimators (7.5–35 mm diameter, BrainLab System) the smallest available detectors should be used for measurements – a diamond diode (0.3 mm thickness) and a 0.015 cm3 ionization chamber (PTW Freiburg) are adequate to measure precisely TMR curves, beam profiles and output factors required for the treatment planning system BrainScan.The full control of accelerator parameters (Clinac 2300 C/D) necessary to safely carry out the treatment requires a comprehensive list of tests (an extended list of weekly checks including Winston-Lutz test). Testing procedure carried out with a set of specialized devices (Med-Tec, Radak, BrainLab) takes about two hours. Proper accelerator check and regulations allow for very precise patient positioning.Treatment planning (with the treatment planning system BrainScan) is based on a series of CT and MR scans with target volume and organs at risk marked on each slice by the radiotherapist. The planner has to select the positions of isocentres (up to 3), collimator diameters, number and range of the arcs. Additional parameters for optimization procedure are the total dose proportions delivered by each arc. The treatment plan evaluation is based on the analysis of DVHs for target volume and also for organs at risk (orbits, optical nerves, brain stem) in order to minimize the dose and volume irradiated. It was accepted that the dose uniformity factor, defined as a ratio Dmin/Dmax within the target volume, should be not less than 0.8, and should approach 0.9 as much as possible.The above-presented system of quality control, specifying tolerance limits of controlled parameters, assures safe and precise dose delivery in stereotactic radiotherapy

    Guidelines for telematic second opinion consultation in headaches in Europe: on behalf of the European Headache Federation

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    The seeking of a second opinion is the long-established process whereby a physician or expert from the same or a similar specialty is invited to assess a clinical case in order to confirm or reject a diagnosis or treatment plan. Seeking a second opinion has become more common in recent years, and the trend is associated with significant changes in the patient-doctor relationship. Telemedicine is attractive because it is not only fast but also affordable and thus makes it possible to reach highly qualified centres and experts that would otherwise be inaccessible, being impossible, or too expensive, to reach by any surface transport. In Europe, the European Headache Federation (EHF), being able to draw on a group of headache experts covering all the European languages, is the organisation best placed to provide qualified second-opinion consultation on difficult headache cases and to develop a Headache Medical Opinion Service Centre. The provision of good quality clinical information is crucial to the formulation of a valid, expert second opinion. This preliminary step can be properly accomplished only by the primary health care provider through the furnishing of an appropriate clinical report, together with the results of all available tests, including original films of all imaging studies already performed. On receiving the EHF's proposed standardised data collection form, properly filled in, we may be sure that we have all the relevant data necessary to formulate a valid expert second opinion. This form can be accessed electronically and downloaded from the EHF website. Once finalised, the EHF second opinion project should be treated as a pilot strategy that requires careful monitoring (for the first year at least), so that appropriate changes, as suggested by the retrospective analysis and its quality control, can be implemented

    Low genetic diversity in Polish populations of sibling ant species: Lasius niger (L.) and Lasius platythorax Seifert (Hymenoptera, Formicidae)

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    We present preliminary data on mitochondrial DNA diversity within and among populations of the ants Lasius niger and Lasius platythorax in Poland. Phylogenetic analysis based on the mitochondrial DNA markers: cytochrome c oxidase subunit I (cox1) and 16S ribosomal RNA (16S rRNA) confirms the species status of L. niger and L. platythorax. Intraspecific variability is low in both species, which might be a result of severe bottlenecks and rapid postglacial expansion into Central Europe

    1H, 13C, and 15N resonance assignments for the tandem PHD finger motifs of human CHD4

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    The plant homeodomain (PHD) zinc finger is a structural motif of about 40–60 amino acid residues found in many eukaryotic proteins that are involved in chromatin-mediated gene regulation. The human chromodomain helicase DNA binding protein 4 (CHD4) is a multi-domain protein that harbours, at its N-terminal end, a pair of PHD finger motifs (dPHD) connected by a ~30 amino acid linker. This tandem PHD motif is thought to be involved in targeting CHD4 to chromatin via its interaction with histone tails. Here we report the 1H, 13C and 15N backbone and side-chain resonance assignment of the entire dPHD by heteronuclear multidimensional NMR spectroscopy. These assignments provide the starting point for the determination of the structure, dynamics and histone-binding properties of this tandem domain pair
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