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Apical Region

The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform

Gregory A Smith – 1st expert on this subject based on the ideXlab platform

  • the Apical Region of the herpes simplex virus major capsid protein promotes capsid maturation
    Journal of Virology, 2018
    Co-Authors: Laura Lee Ruhge, Alexis Huet, James F Conway, Gregory A Smith

    Abstract:

    The herpesvirus capsid assembles in the nucleus as an immature procapsid precursor built around viral scaffold proteins. The event that initiates procapsid maturation is unknown, but it is dependent upon activation of the VP24 internal protease. Scaffold cleavage triggers angularization of the shell and its decoration with the VP26 and pUL25 capsid-surface proteins. In both the procapsid and mature angularized capsid, the Apical Region of the major capsid protein (VP5) is surface exposed. We investigated whether the VP5 Apical Region contributes to intracellular transport dynamics following entry into primary sensory neurons and also tested the hypothesis that conserved negatively charged amino acids in the Apical Region contribute to VP26 acquisition. To our surprise, neither hypothesis proved true. Instead, mutation of glutamic acid residues in the Apical Region delayed viral propagation and induced focal capsid accumulations in nuclei. Examination of capsid morphogenesis based on epitope unmasking, capsid composition, and ultrastructural analysis indicated that these clusters consisted of procapsids. The results demonstrate that, in addition to established events that occur inside the capsid, the exterior capsid shell promotes capsid morphogenesis and maturation.

    IMPORTANCE Herpesviruses assemble capsids and encapsidate their genomes by a process that is unlike those of other mammalian viruses but is similar to those of some bacteriophage. Many important aspects of herpesvirus morphogenesis remain enigmatic, including how the capsid shell matures into a stable angularized configuration. Capsid maturation is triggered by activation of a protease that cleaves an internal protein scaffold. We report on the fortuitous discovery that a Region of the major capsid protein that is exposed on the outer surface of the capsid also contributes to capsid maturation, demonstrating that the morphogenesis of the capsid shell from its procapsid precursor to the mature angularized form is dependent upon internal and external components of the megastructure.

  • the Apical Region of the herpes simplex virus major capsid protein promotes capsid maturation
    bioRxiv, 2018
    Co-Authors: Laura Lee Ruhge, Alexis Huet, James F Conway, Gregory A Smith

    Abstract:

    The herpesvirus capsid assembles in the nucleus as an immature procapsid precursor built around viral scaffold proteins. The event that initiates procapsid maturation is unknown, but it is dependent upon activation of the VP24 internal protease. Scaffold cleavage triggers angularization of the shell and its decoration with the VP26 and pUL25 capsid-surface proteins. In both the procapsid and mature angularized capsid, the Apical Region of the major capsid protein (VP5) is surface exposed. We investigated whether the VP5 Apical Region contributes to intracellular transport dynamics following entry into primary sensory neurons and also tested the hypothesis that conserved negatively-charged amino acids in the Apical Region contribute to VP26 acquisition. To our surprise neither hypothesis proved true. Instead, mutation of glutamic acid residues in the Apical Region delayed viral propagation and induced focal capsid accumulations in nuclei. Examination of capsid morphogenesis based on epitope unmasking, capsid composition, and ultrastructural analysis indicated that these clusters consisted of procapsids. The results demonstrate that, in addition to established events that occur inside the capsid, the exterior capsid shell promotes capsid morphogenesis and maturation.

Djoko Suharto – 2nd expert on this subject based on the ideXlab platform

  • visualization of removal of trapped air from the Apical Region in simulated root canals by laser activated irrigation using an er cr ysgg laser
    Lasers in Medical Science, 2015
    Co-Authors: Harry Huiz Peeters, Roeland De Moor, Djoko Suharto

    Abstract:

    The aim of this visualization study was to obtain a better understanding of the mechanism by which trapped air is removed from the Apical Region of simulated root canals by activation of an irrigant using an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser during endodontic procedures. A high-speed imaging system with high temporal and spatial resolution was used to visualize laser-induced shock waves in a resin block model with a curved root canal (inner diameter at the apex 0.08 mm, taper 4 %, crown height 10 mm, overall length 40 mm) and a glass cylinder model with a straight root canal (inner diameter 1 mm, crown height 10 mm, overall length 40 mm). The study utilized MZ3 and RFT3 tips in each model, without water or air spray, and with an average power of 1 W at 35 Hz. Laser-activated irrigation overcame the airlock effect by releasing air trapped in the air column. The mechanism underlying the removal of trapped air from the Apical Region using an Er,Cr:YSGG laser in a dry root canal is via the disruption of the surface tension at the solution-air interface. This disruption, caused by bubble implosion (cavitation), displaces air in the form of bubbles from the Apical Region toward the solution, which allows the solution to travel Apically.

  • visualization of removal of trapped air from the Apical Region of the straight root canal models generating 2 phase intermittent counter flow during ultrasonically activated irrigation
    Journal of Endodontics, 2014
    Co-Authors: Harry Huiz Peeters, Bernard Ongki Iskandar, Ketut Suardita, Djoko Suharto

    Abstract:

    Abstract Introduction The purpose of this in vitro study was to obtain a better understanding of the mechanism of irrigant traveling Apically and generating 2-phase intermittent counter flow in straight root canal models during activation of the irrigant by ultrasonic means in an endodontic procedure. Methods A high-speed imaging system, with high temporal and spatial resolution (FastCam SA5; Photron, Tokyo, Japan) at a frame rate of 100,000 frames per second using a macro lens (60 mm, f/2.8; Nikon, Tokyo, Japan), was used to visualize, in glass models of root canals, an ultrasonically induced acoustic pressure wave in an EDTA solution environment. A 25-mm stainless steel noncutting file #20 driven by an ultrasonic device (P5 Newtron; Satelec Acteon, Merignac, France) at power settings of 5 and 7 produced disturbances at the solution-air interface. Results We found that Apically directed travel of the irrigant was caused by disruption of the surface tension at the solution-air interface. This disruption caused by ultrasonic activation energy displaced air in the form of bubbles from the Apical Region toward the solution. Conclusions The Apical movement of the solution may be attributed to ultrasonically induced wave generation at the solution-air interface, resulting in the removal of trapped air from the root canal and allowing the solution to travel Apically in the opposite directions (via a 2-phase intermittent counter flow).

Laura Lee Ruhge – 3rd expert on this subject based on the ideXlab platform

  • the Apical Region of the herpes simplex virus major capsid protein promotes capsid maturation
    Journal of Virology, 2018
    Co-Authors: Laura Lee Ruhge, Alexis Huet, James F Conway, Gregory A Smith

    Abstract:

    The herpesvirus capsid assembles in the nucleus as an immature procapsid precursor built around viral scaffold proteins. The event that initiates procapsid maturation is unknown, but it is dependent upon activation of the VP24 internal protease. Scaffold cleavage triggers angularization of the shell and its decoration with the VP26 and pUL25 capsid-surface proteins. In both the procapsid and mature angularized capsid, the Apical Region of the major capsid protein (VP5) is surface exposed. We investigated whether the VP5 Apical Region contributes to intracellular transport dynamics following entry into primary sensory neurons and also tested the hypothesis that conserved negatively charged amino acids in the Apical Region contribute to VP26 acquisition. To our surprise, neither hypothesis proved true. Instead, mutation of glutamic acid residues in the Apical Region delayed viral propagation and induced focal capsid accumulations in nuclei. Examination of capsid morphogenesis based on epitope unmasking, capsid composition, and ultrastructural analysis indicated that these clusters consisted of procapsids. The results demonstrate that, in addition to established events that occur inside the capsid, the exterior capsid shell promotes capsid morphogenesis and maturation.

    IMPORTANCE Herpesviruses assemble capsids and encapsidate their genomes by a process that is unlike those of other mammalian viruses but is similar to those of some bacteriophage. Many important aspects of herpesvirus morphogenesis remain enigmatic, including how the capsid shell matures into a stable angularized configuration. Capsid maturation is triggered by activation of a protease that cleaves an internal protein scaffold. We report on the fortuitous discovery that a Region of the major capsid protein that is exposed on the outer surface of the capsid also contributes to capsid maturation, demonstrating that the morphogenesis of the capsid shell from its procapsid precursor to the mature angularized form is dependent upon internal and external components of the megastructure.

  • the Apical Region of the herpes simplex virus major capsid protein promotes capsid maturation
    bioRxiv, 2018
    Co-Authors: Laura Lee Ruhge, Alexis Huet, James F Conway, Gregory A Smith

    Abstract:

    The herpesvirus capsid assembles in the nucleus as an immature procapsid precursor built around viral scaffold proteins. The event that initiates procapsid maturation is unknown, but it is dependent upon activation of the VP24 internal protease. Scaffold cleavage triggers angularization of the shell and its decoration with the VP26 and pUL25 capsid-surface proteins. In both the procapsid and mature angularized capsid, the Apical Region of the major capsid protein (VP5) is surface exposed. We investigated whether the VP5 Apical Region contributes to intracellular transport dynamics following entry into primary sensory neurons and also tested the hypothesis that conserved negatively-charged amino acids in the Apical Region contribute to VP26 acquisition. To our surprise neither hypothesis proved true. Instead, mutation of glutamic acid residues in the Apical Region delayed viral propagation and induced focal capsid accumulations in nuclei. Examination of capsid morphogenesis based on epitope unmasking, capsid composition, and ultrastructural analysis indicated that these clusters consisted of procapsids. The results demonstrate that, in addition to established events that occur inside the capsid, the exterior capsid shell promotes capsid morphogenesis and maturation.