Siphoviridae_virion
Siphoviridae_virion

Fusobacterium nucleatum is a periodontal pathogen that has been directly associated with the development and progression of periodontal disease, a widespread pathology that affects the support tissues of the tooth. We isolated a new bacteriophage (FnpΦ02) that specifically infects this bacterium. Transmission electron microscopy showed that the virion is composed of an icosahedral head and a segmented tail. The size of the phage genome was estimated to be approximately 59 kbp of double-stranded DNA. The morphological features and the genetic characteristics suggest that FnpΦ02 is part of the Siphoviridae family. Using one-step growth and adsorption experiments, the latent period, burst size, and adsorption rate were estimated to be 15 h, 100 infectious units per cell, and 7.5 × 10⁻¹⁰ ml min⁻¹, respectively. A small fragment of phage DNA was cloned and sequenced, showing 93% nucleotide identity with the phage PA6 of Propionibacterium acnes and amino acid identity with fragments of two proteins (Gp3 and Gp4) of this phage. To our knowledge, FnpΦ02 is the first phage described to infect Fusobacterium nucleatum and provides the base for future exploration of phages in the control of periodontal disease.
Most cited papers:
Arch Virol. 2002 Dec ;147 (12):2419-29  12491107  Cit:29
Remarkable morphological diversity of viruses and virus-like particles in hot terrestrial environments.
R Rachel, M Bettstetter, B P Hedlund, M Häring, A Kessler, K O Stetter, D Prangishvili
Lehrstuhl für Mikrobiologie und Archaeenzentrum, Universität Regensburg, Germany.
Electron microscopic studies of the viruses in two hot springs (85 degrees C, pH 1.5-2.0, and 75-93 degrees C, pH 6.5) in Yellowstone National Park revealed particles with twelve different morphotypes. This diversity encompassed known viruses of hyperthermophilic archaea, filamentous Lipothrixviridae, rod-shaped Rudiviridae, and spindle-shaped Fuselloviridae, and novel morphotypes previously not observed in nature. Two virus types resembled head-and-tail bacteriophages from the families Siphoviridae and Podoviridae, and constituted the first observation of these viruses in a hydrothermal environment. Viral hosts in the acidic spring were members of the hyperthermophilic archaeal genus Acidianus.
J Struct Biol. ;138 (1-2):105-13  12160706  Cit:25
Segmentation of two- and three-dimensional data from electron microscopy using eigenvector analysis.
Achilleas S Frangakis, Reiner Hegerl
Max-Planck-Institut für Biochemie, Am Klopferspitz 18a, D-8215 Martinsried, Germany.
An automatic image segmentation method is used to improve processing and visualization of data obtained by electron microscopy. Exploiting affinity criteria between pixels, e.g., proximity and gray level similarity, in conjunction with an eigenvector analysis, the image is subdivided into areas which correspond to objects or meaningful regions. Extending a proposal by Shi and Malik (1997, Proceedings of the IEEE conference on Computer Vision and Pattern Recognition, pp. 731-737) the approach was adapted to the field of electron microscopy, especially to three-dimensional application as needed by electron tomography. Theory, implementation, parameter setting, and results obtained with a variety of data are presented and discussed. The method turns out to be a powerful tool for visualization with the potential for further improvement by developing and tuning new affinity.
Science. 2001 Apr 27;292 (5517):744-8  11326105  Cit:14
Virus maturation involving large subunit rotations and local refolding.
J F Conway, W R Wikoff, N Cheng, R L Duda, R W Hendrix, J E Johnson, A C Steven
Laboratory of Structural Biology Research, National Institute of Arthritis, Musculoskeletal and Skin Diseases, Bethesda, MD 20892, USA.
Large-scale conformational changes transform viral precursors into infectious virions. The structure of bacteriophage HK97 capsid, Head-II, was recently solved by crystallography, revealing a catenated cross-linked topology. We have visualized its precursor, Prohead-II, by cryoelectron microscopy and modeled the conformational change by appropriately adapting Head-II. Rigid-body rotations ( approximately 40 degrees) cause switching to an entirely different set of interactions; in addition, two motifs undergo refolding. These changes stabilize the capsid by increasing the surface area buried at interfaces and bringing the cross-link-forming residues, initially approximately 40 angstroms apart, close together. The inner surface of Prohead-II is negatively charged, suggesting that the transition is triggered electrostatically by DNA packaging.
J Bacteriol. 2005 Jun ;187 (12):4187-97  15937180  Cit:12
Structural characterization and assembly of the distal tail structure of the temperate lactococcal bacteriophage TP901-1.
Christina S Vegge, Lone Brøndsted, Horst Neve, Stephen Mc Grath, Douwe van Sinderen, Finn K Vogensen
Department of Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
The tail structures of bacteriophages infecting gram-positive bacteria are largely unexplored, although the phage tail mediates the initial interaction with the host cell. The temperate Lactococcus lactis phage TP901-1 of the Siphoviridae family has a long noncontractile tail with a distal baseplate. In the present study, we investigated the distal tail structures and tail assembly of phage TP901-1 by introducing nonsense mutations into the late transcribed genes dit (orf46), tal(TP901-1)(orf47), bppU (orf48), bppL (orf49), and orf50. Transmission electron microscopy examination of mutant and wild-type TP901-1 phages showed that the baseplate consisted of two different disks and that a central tail fiber is protruding below the baseplate. Evaluation of the mutant tail morphologies with protein profiles and Western blots revealed that the upper and lower baseplate disks consist of the proteins BppU and BppL, respectively. Likewise, Dit and Tal(TP901-1) were shown to be structural tail proteins essential for tail formation, and Tal(TP901-1) was furthermore identified as the tail fiber protein by immunogold labeling experiments. Determination of infection efficiencies of the mutant phages showed that the baseplate is fundamental for host infection and the lower disk protein, BppL, is suggested to interact with the host receptor. In contrast, ORF50 was found to be nonessential for tail assembly and host infection. A model for TP901-1 tail assembly, in which the function of eight specific proteins is considered, is presented.
Appl Environ Microbiol. 2005 Mar ;71 (3):1598-609  15746365  Cit:11
Genomic analysis of bacteriophage PhiJL001: insights into its interaction with a sponge-associated alpha-proteobacterium.
Jayme E Lohr, Feng Chen, Russell T Hill
Center of Marine Biotechnology, Columbus Center Suite 236, 701 East Pratt Street, Baltimore, MD 21202, USA.
Bacteriophage PhiJL001 infects a novel marine bacterium in the alpha subclass of the Proteobacteria isolated from the marine sponge Ircinia strobilina. PhiJL001 is a siphovirus and forms turbid plaques on its host. The genome sequence of PhiJL001 was determined in order to better understand the interaction between the marine phage and its sponge-associated host bacterium. The complete genome sequence of PhiJL001 comprised 63,469 bp with an overall G+C content of 62%. The genome has 91 predicted open reading frames (ORFs), and 17 ORFs have been assigned putative functions. PhiJL001 appears to be a temperate phage, and the integrase gene was identified in the genome. DNA hybridization analysis showed that the PhiJL001 genome does not integrate into the host chromosome under the conditions tested. DNA hybridization experiments therefore suggested that PhiJL001 has some pseudolysogenic characteristics. The genome of PhiJL001 contains many putative genes involved in phage DNA replication (e.g., helicase, DNA polymerase, and thymidylate synthase genes) and also contains a putative integrase gene associated with the lysogenic cycle. Phylogeny based on DNA polymerase gene sequences indicates that PhiJL001 is related to a group of siphoviruses that infect mycobacteria. Designation of PhiJL001 as a siphovirus is consistent with the morphology of the phage visualized by transmission electron microscopy. The unique marine phage-host system described here provides a model system for studying the role of phages in sponge microbial communities.
Virology. 2000 Oct 25;276 (2):315-28  11040123  Cit:9
Mutational analysis of two structural genes of the temperate lactococcal bacteriophage TP901-1 involved in tail length determination and baseplate assembly.
M Pedersen, S Ostergaard, J Bresciani, F K Vogensen
Department of Dairy and Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, Frederiksberg C, DK-1958, Denmark.
Two putative structural genes, orf tmp (tape measure protein) and orf bpp (baseplate protein), of the temperate lactococcal phage TP901-1 were examined by introduction of specific mutations in the prophage strain Lactococcus lactic ssp. cremoris 901-1. The adsorption efficiencies of the mutated phages to the indicator strain L. lactic ssp. cremoris 3107 were determined and electron micrographs were obtained. Specific mutations in orf tmp resulted in the production of mostly phage head structures without tails and a few wild-type looking phages. Furthermore, construction of an inframe deletion or duplication of 29% in orf tmp was shown to shorten or lengthen the phage tail by approximately 30%, respectively. The orf tmp is proposed to function as a tape measure protein, TMP, important for assembly of the TP901-1 phage tail and involved in tail length determination. Specific mutations in orf bpp produced phages which were unable to adsorb to the indicator strain and electron microscopy revealed particles lacking the baseplate structure. The orf bpp is proposed to encode a highly immunogenic structural baseplate protein, BPP, important for assembly of the baseplate. Finally, an assembly pathway of the TP901-1 tail and baseplate structure is presented.
J Appl Microbiol. 1999 Sep ;87 (3):402-9  10540243  Cit:9
Study of the potential relationship between the morphology of infectious somatic coliphages and their persistence in the environment.
M Muniesa, F Lucena, J Jofre
Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Spain.
The proportions of different morphological types of infectious somatic coliphages were determined in faecally polluted freshwaters. Myoviridae, followed by Siphoviridae, were the most frequently isolated morphological types in raw sewage, treated sewage and river water collected a few metres downstream from a sewage outfall. However, in river water collected further downstream from the pollution point, in river water after ‘in situ’ inactivation experiments and in chlorinated raw and treated sewage significant changes in the proportions of the different somatic coliphage morphological types occurred. In all cases, Siphoviridae, especially those with flexible and curled tails, became more abundant to the detriment of Myoviridae.
Arch Virol. 1996 ;141 (2):209-18  8634015  Cit:8
Frequency of morphological phage descriptions in 1995.
H W Ackermann
Félix d’Hérelle Reference Center for Bacterial Viruses, Department ofMicrobiology, Faculty of Medicine, Laval University, Québec, Cananda.
At least 4500 bacterial viruses have been examined in the electron microscope since 1959. About 4400 phages (96%) are tailed and only 162 phages (4%) are cubic, filamentous, or pleomorphic. Phages belong to 12 virus families and occur in about 130 bacterial genera. Phages are listed by morphotypes and host genera. Siphoviridae or phages with long, noncontractile tails include about 60% of tailed phages.
Arch Virol. 1997 ;142 (7):1381-90  9267450  Cit:7
Taxonomic changes in tailed phages of enterobacteria.
H W Ackermann, M S DuBow, M Gershman, B Karska-Wysocki, S S Kasatiya, M J Loessner, M D Mamet-Bratley, M Regué
Félix d’Hérelle Reference Center for Bacterial Viruses, Department of Microbiology, Faculty of Medicine, Laval University, Quebec, Canada.
Out of 136 new phages, 80 (59%) are classified into 23 species according to morphology and physicochemical properties. Six new species are described and species beta 4, from a previous classification scheme, is renamed T1. The morphology of 36 phage species is schematically represented.
Arch Virol. 1994 ;135 (3-4):345-54  7979972  Cit:7
Classification of Acinetobacter phages.
H W Ackermann, G Brochu, H P Emadi Konjin
Félix d’Hérelle Reference Center for Bacterial Viruses, Department of Microbiology, Faculty of Medicine, Laval University, Quebec, Sainte-Foy, Canada.
Eight phage species and type viruses are proposed. They belong to the Myoviridae, Siphoviridae, and Podoviridae families of tailed phages and are characterized by a combination of morphological and physicochemical properties. An unusual siphovirus species has an elongated head and transverse tail disks.

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sederhana, tidak cakep dan tidak keren

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