Sunday, January 27, 2013

Should science be apolitical?

Read the other day in the magazine the Atlantic: “The danger of making science political”, by Puneet Opal, medical doctor and professor of neurology at the Northwestern University Feinberg School of Medicine. Opal reflects on the relation between science and politics; he observes that, in the US, science is associated with the Democrat party, and he asks the question: why is it so?

Opal’s article is echoing another piece published recently in Nature, “Science must be seen to bridge the political divide”, by Daniel Sarewitz, from the Consortium for Science, Policy and Outcomes at Arizona State University. Sarewitz complains about a very US-centered situation, that is, the fact that most American scientists seem to side with the Democrats against the Republicans. He takes as an example the letter written by many Nobel laureates in support of Obama’s reelection in 2012. This bias, Sarewitz claims, is a bad thing for science. He writes:

“To prevent science from continuing its worrying slide towards politicization, here’s a New Year’s resolution for scientists, especially in the United States: gain the confidence of people and politicians across the political spectrum by demonstrating that science is bipartisan.”

Friday, January 18, 2013

Plant pathogen focus: Pierce's disease and the vineyards of California

Grapevine dying of Pierce's disease. Photo courtesy of PD-GWSS/CDFA.
Xylella fastidiosa  is not your ordinary kind of bug. It made it to the list of the most wanted plant pathogenic bacteria in 2012! (Mansfield, 2012.)

This is well deserved: X. fastidiosa can infect over a hundred species (grapevine, oleander, citrus, almonds,…), and it causes severe symptoms that can kill the infected plant. The Xylella bacteria colonize the xylem vessels, and by doing so they block the transport of water in the plant. The water-deprived leaves dry and scorch, until finally they drop to the ground. 

In 1892, Newton Pierce, California’s first professional plant pathologist, described the disease that now bears his name, although he failed to identify the causative agent of the disease (X. fastidiosa). Around the end of the 19th century, an epidemic of Pierce’s disease devastated thousands of hectares of vineyards in the Los Angeles Basin. Since then, southern California has considerably reduced its viticulture; this also explains why present-day Californian vineyards are mostly restricted to the north of the state. There is currently no other cure than getting rid of the infected plants!

Sunday, January 06, 2013

The new biology of Carl Woese

Carl Woese. Photo courtesy of Don Hamerman.

Carl Woese, one of the giants of contemporary biology, passed away a day before New Year’s Eve (see the NY Times obituary). Woese, an American microbiologist from the University of Illinois, revolutionized our understanding of life with the discovery of a new domain of living organisms, the Archaea, and the creation of a universal tree of life made of three main branches (Bacteria, Archaea and Eukarya) (Woese, 1990). This discovery is already more than thirty years old, but is not very well known to the general public, to say the least… And now with Woese’s death the possibility of a Nobel nomination vanishes.

Everything we do nowadays in microbiology labs is to some extent influenced by the work done by Woese in the seventies and eighties. This is one reason why I entitled this post “The new biology of Carl Woese”. The other reason is a 2004 article by Woese, “A new biology for anew century”, which offers a great perspective on our job and which contains some juicy controversial elements. But let’s begin with the landmark contribution of Woese to the field of biology.

Before the sixties and the advent of molecular phylogeny, the classification of bacteria seemed an insoluble problem, since morphology and metabolism were not good enough to allow us to order the bacterial life forms. Woese, a physicist by training, decided in 1966 that he could give it a try using the powerful tools of molecular biology. At that time many researchers had turned towards proteins in order to build phylogenetic trees, following the pioneer work of Linus Pauling on hemoglobin. Woese didn’t follow the consensus and decided to use ribosomal RNA as source material. Thanks to a tedious technique called oligonucleotide cataloging, he was able to reconstruct the rRNA sequence and did that for about sixty bacteria. It took ten years.