id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-022196-1tionxun	FENNER, FRANK	The Nature and Classification of Animal Viruses	2013-11-17		.txt	text/plain	9588	406	46	With most isometric particles and in all complex virions, the capsid encloses another protein structure containing the viral genome, called the core. All animal viruses with tubular nucleocapsids are enveloped, and in these the lipid layer from which glycoprotein peplomers project is probably applied to a protein shell (the membrane protein; see Fig. 1 -1), which may be relatively rigid, as in Rhabdovirus, or readily distorted (as in the myxoviruses) so that in negatively stained electron micrographs the virions appear to be pleomorphic. The RNA viruses that have the largest (single-stranded) genomes, those of the Leukovirus genus, also have a highly complex structure with an envelope enclosing an icosahedral capsid that, in turn, surrounds a tubular nucleocapsid. The conventional physicochemical criteria [(a) nucleic acid: type, strandedness, fragmentation, and molecular weight; (b) virion: shape, size, and symmetry] are suitable for classification at this level of family/genus, perhaps assisted by the serological cross-reactivity of "group" antigens where these have been recognized.	./cache/cord-022196-1tionxun.txt	./txt/cord-022196-1tionxun.txt