key: cord-0004927-4yinnncj authors: Tajima, M. title: Morphology of transmissible gastroenteritis virus of pigs: A possible member of coronaviruses date: 1970 journal: Arch Gesamte Virusforsch DOI: 10.1007/bf01253886 sha: fb11c63ac7ca2c5a32f08511c9167afb953dfc30 doc_id: 4927 cord_uid: 4yinnncj nan Moderate numbers of virus particles were observed in preparations made from the infected culture fluid. They were distributed over the grid surface singly or in small groups (Figs. 1--3) . The particles were pleomorphic and variable in size but were predominantly circular in outline with diameters between 100 and 150 m~, including surface projections. The surface of most particles seen in the specimens prepared immediately after harvesting the culture fluid was covered with distinctive projections approximately 24 m~ long ( Figs. 1 and 2) . The projections were various in shape but were mostly petal-shaped in outline, and attached to the particle by a very narrow stalk. The widest part measured approximately 10 m~ in diameter. The projections seemed to be easily detached from the virus and they were often observed only on a limited area of the particle surface. In the specimens prepared from the culture fluid stored frozen at --20~ for about one month, approximately one half of the particles showed no projections (Fig. 3) . As a result of some penetration of phosphotungstate to the interior, an electronopaque central area and an envelope approximately 10 m~ in thickness were observed in some of the particles (Fig. 3) . Spontaneous disruption of the particles was sometimes seen. Even in such disrupted particles, no distinct internal component could be recognized. The morphology of TGE virus described here agrees well with that of previous authors (1], 15) except that WITTE et al. (15) could not demonstrate surface pro-jections. The projections which give a characteristic appearance to TGE virus seem to be readily lost or damaged and it is probable that the particles observed by WITTE et al. (15) lost their projections during the process of purification. It is interesting to note that the particles of TGE virus are morphologically indistinguishable from those of the coronaviruses which have recently been proposed as a new group of viruses (1). TGE virus is ether-labile (5, 7, 8, ]2--14), contains ribonucleic acid (no inhibition by deoxyribonucleic acid inhibitors) (7, 15) , and replicates in the cytoplasm by a process of budding from membranes of the endoplasmic reticulum and vesicles (15) . These properties of TGE virus are in ~greement with those of the coronaviruses (1--4, 6, 9, 10) , and provide further support for the assumption that it belongs to the coronaviruses. The morphology of three previously uncharacterized human respiratory viruses that grow in organ culture Morphogenesis of avian infectious bronchitis virus and a related human virus (strain 229E) The structure of infectious bronchitis virus Transmissible gastroenteritis of pigs Growth and intracellular development of a new respiratory virus Studies on transmissible gastroenteritis in pigs. IV. Physicoehemical and biological properties of TGE virus NOI~AN: Studies on transmissible gastroenteritis of swine. II. Selected characteristics of a eytopathogenic virus common to five isolates from transmissible gastroenteritis CHANOCK : Recovery in tracheal organ cultures of novel viruses from patients with respiratory disease NNINGHA~: Morphogenesis of avian infectious bronchitis virus in chicken embryo fibroblasts Structure of swine gastroenteritis virus examined by negative staining Die Tenazit~it des Virus der infekti5sen Gastroenteritis der Schweine Electron microscopy and ether sen-'sitivity of transmissible gastroenteritis virus of swine EASTERDAY: Isolation and propagation of the virus of transmissible gastroenteritis of pigs in various pig cell cultures. Arch. ges. Virusforseh EASTERDAY: Morphologic characteristic and nucleic acid type of transmissible gastroenteritis virus of pigs. Arch. ges. Virusforsch Author's address: Dr. M. TAJIMA, Nippon Institute for Biological Science