Provirophages and transpovirons as the diverse mobilome of giant viruses
Abstract: A distinct class of infectious agents, the virophages1 that infect giant viruses of the Mimiviridae family, has been recently described. Here we report the simultaneous discovery of a giant virus of Acanthamoeba polyphaga (Lentille virus) that contains an integrated genome2 of a virophage (Sputnik 2), and a member of a previously unknown class of mobile genetic elements3, the transpovirons4. The transpovirons are linear DNA elements of ∼7 kb [kilobases]5 that encompass six to eight protein-coding genes, two of which are homologous6 to virophage genes. Fluorescence7 in situ hybridization8 showed that the free form of the transpoviron replicates within the giant virus factory and accumulates in high copy numbers inside giant virus particles, Sputnik 2 particles, and amoeba cytoplasm. Analysis of deep-sequencing data showed that the virophage and the transpoviron can integrate9 in nearly any place in the chromosome of the giant virus host and that, although less frequently, the transpoviron can also be linked to the virophage chromosome. In addition, integrated fragments of transpoviron DNA were detected in several giant virus and Sputnik genomes. Analysis of 19 Mimivirus strains revealed three distinct transpovirons associated with three subgroups of Mimiviruses. The virophage, the transpoviron, and the previously identified self-splicing introns10 and inteins11 constitute the complex, interconnected mobilome12 of the giant viruses and are likely to substantially contribute to interviral gene transfer.[Full Text PDF] and two explanations in English [more inside]
The Real Science Gap:
“There is no scientist shortage,” declares Harvard economics professor Richard Freeman, a pre-eminent authority on the scientific work force. Michael Teitelbaum of the Alfred P. Sloan Foundation, a leading demographer who is also a national authority on science training, cites the “profound irony” of crying shortage — as have many business leaders, including Microsoft founder Bill Gates — while scores of thousands of young Ph.D.s labor in the nation’s university labs as low-paid, temporary workers, ostensibly training for permanent faculty positions that will never exist.
On Nov. 3, 1957, the Soviet Union launched Sputnik 2, a one-way, history-making trip for a dog named Laika. Take a moment to remember her. [more inside]
The year was 1957: the Soviet Union had launched the cutest little sattelite ever. And it didn't just look good, it sounded good, too! As sweet a sound as any avant garde composer of the 1950's might dream up! Of course, the US would have to get a little metal ball of its own into space, but things didn't go so well. They did manage to get one up there in 1958, but nobody knows if it sounded as good as ol' Sputnik. But anyway, most folks weren't listening to satellites 50 years ago, they were listening to, well, lessee, there was... [more inside]
Fifty years ago this week the heavens beeped (also, the beeps as recorded in Germany, Czechoslovakia, and Washington - though the accompanying light in the sky wasn't Sputnik after all). The launch of Sputnik started the Space Age causing a stir in the United States, and leading to the birth of NASA. The history and ongoing echoes of the Sputnik launch are wonderfully covered in a recent New York Times retrospective with interesting accompanying videos.
Sputnik rides again: Follow the amazing adventures of Sputnik the crocadilly. What was he up to August 7th? In metioning anything crocky, we should give a shout out to old Rol.
Do you consider yourself a latter-day "beatnik"? Even young fans of Jack Kerouac and Allen Ginsberg proudly christen themselves with the tag beatnik these days, apparently unaware that word was originally coined as a term of ridicule by San Francisco columnist Herb Caen. "Beat" was indeed used by Kerouac to denote both "beaten down" and "beatitude" -- a state of revelation. He first heard the word spoken by a Times Square hustler and writer named Herbert Huncke; then another writer, John Clellon Holmes, popularized the term "Beat" in a New York Times article headlined "This is the Beat Generation." But the original Beats did not approve of the term "beatnik" -- combining "beat" with the Russian "Sputnik," as if to suggest that the Beat writers were both "out there" and vaguely Communist -- as this hilarious dialogue [note: MP3 link] between a very young Ginsberg, anthropologist Margaret Mead, and an excruciatingly square talk-radio host makes plain.
On October 4, 1957 the Soviet Union launched Sputnik, the first man-made object ever sent into space...
On October 4, 1957 the Soviet Union launched Sputnik, the first man-made object ever sent into space... Sputnik: The Shock of the Century, a book by Paul Dickson released today, is a fascinating look into the historical, political, social and technological ramifications of the Russian sattellite that launched the Space Race, and changed the course of how information traveled. (Today is my birthday, as well—which should explain my interest in the subject.)