Pages

Friday, June 17, 2011

The recent discovery of really, really big viruses is changing views about the nature of viruses and the history of life


The common view of viruses, mostly true, is of tiny burglars that sneak into cells, grab the biosynthetic controls and compel the cell to make huge numbers of progeny that break out of the cell and keep the replication cycle going. Viruses are supposed to be diminutive even compared to cells that are just a micrometer (1,000 nanometers) in diameter. They are supposed to travel light, making do with just a few well-adapted genes.
 
In 1992, a new microorganism was isolated from a power-plant cooling tower in Bradford, England, where Timothy Robotham, a microbiologist at Leeds Public Health Laboratory, was seeking the causative agent of a local pneumonia outbreak. His search led to the warm waters of the cooling tower, a known reservoir for bacterial pathogens in the Legionella genus, which are the cause of the pneumonialike Legionnaire’s disease. Particles present in the sample were mistakenly identified as bacteria. Gram positive and visible under the microscope as pathogens within the particle-gobbling amoeba Acanthamoeba polyphaga, the entities surprisingly did not generate any product from the gene-amplifying polymerase chain reaction technique using universal bacterial primers.

Eleven years later, in 2003, the mystery organism received a new identity and a new name, Acanthamoeba polyphaga Mimivirus, for microbe-mimicking virus. Mimivirus is the largest virus ever discovered. Giant viruses had been known for a few years, many of them in a group termed nucleo-cytoplasmic large DNA viruses (NCLDVs). This group features several other virus families, including Poxviridae, which infects vertebrates (for example, smallpox virus) and invertebrates, the aquatic viruses Iridoviridae and Phycodnaviridae, and the vertebrate virus Asfarviridae. Giant viruses are considered to be ones with genomes larger than 300 kilobase pairs and with capsid diameters of about 200 nanometers or more.
James L. Van Etten in American Scientist: Here

17 comments:

Anonymous said...

diazepam online buy diazepam thailand - diazepam keeps me awake

Anonymous said...

cheapest ativan ativan 3.5 mg - ativan information

Anonymous said...

buy diazepam diazepam drug users - diazepam 5g side effects

Anonymous said...

buy ativan online typical ativan dosage - ativan side effects

Anonymous said...

order xanax online risque overdose xanax - generic xanax pill pictures

Anonymous said...

buy ativan lorazepam 1mg tabletten - how to buy ativan online no prescription

Anonymous said...

buy xanax online forum xanax withdrawal regimen - xanax and alcohol

Anonymous said...

ativan no prescription ativan dosage instructions - ativan dosage 2mg

Anonymous said...

online xanax xanax withdrawal 1 mg day - xanax for generalized anxiety disorder

Anonymous said...

ambien pill price ambien without insurance - ambience mall gurgaon pvr phone number

Anonymous said...

ambien online purchase ambien cr dosage information - ambien show drug test

Anonymous said...

order valium online valium severe depression - 5mg valium to xanax

Anonymous said...

buy soma online carisoprodol for back pain - soma medication overnight

Anonymous said...

buy valium valium joint - 5mg valium prescribed

Anonymous said...

valium anxiety diazepam valium sale - buy valium online in australia

Anonymous said...

valium pharmacy valium dosage range - valium online usa

Anonymous said...

t, cheap generic levitra - buy levitra no prescription http://www.levitrapillsforsale.net/#buy-levitra-no-prescription , [url=http://www.levitrapillsforsale.net/#vardenafil-without-prescription ]vardenafil without prescription [/url]

Translate

Related Posts Plugin for WordPress, Blogger...