id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-018437-yjvwa1ot	Mitchell, Michael	Taxonomy	2013-08-26		.txt	text/plain	9283	561	48	Classifi cation is based on the genomic nucleic acid used by the virus (DNA or RNA), strandedness (single or double stranded), and method of replication. The nucleocapsids of some viruses are surrounded by envelopes composed of lipid bilayers and host-or viral-encoded proteins. The sequence of negative-sense ssRNA is complementary to the coding sequence for translation, so mRNA must be synthesized by RNA polymerase, typically carried within the virion, before translation into viral proteins. Among the families of viruses able to infect humans and other vertebrate hosts, there are many species that target and cause disease in the lung. The nucleocapsid is surrounded by an envelope derived from host-cell membrane and viral envelope proteins, including hepatitis B surface antigen. The genome of human parainfl uenza viruses is ~15 kb in length with an organization and six reading frames (N, P, M, F, HN, L) typical of the Paramyxoviridae (Karron and Collins 2007 ) .	./cache/cord-018437-yjvwa1ot.txt	./txt/cord-018437-yjvwa1ot.txt