The magazine of the european research area European Commission Copenhagen, a missed chance?

  www.univ-lille2.fr

www.alzheimers-research.org.uk

From lithium 

mystery to 

exoplanets

For over 60 years scientists have 

wondered why the sun contains 

less lithium than many similar 

stars. According to the study 

published in Nature in November 

2009 by the team of astrophysicist 

Garik Israelian of the Institute of 

Astrophysics of the Canary 

Islands (ES), the mystery is solved: 

it is because our star is surrounded 

by planets. 

For several years the European 

South Observatory (ESO) has 

been observing 500 stars, includ-

ing 70 surrounded by planets, 

using the High Accuracy Radial 

Velocity Planet Searcher (HARPS) 

spectrograph of its 3.6-metre-

diameter telescope at La Silla, 

Chile. By focusing only on stars 

comparable to the sun, which 

make up about one quarter of 

the sample, Garik Israelian and 

his team noted that the majority 

of those that are surrounded 

by planets contain about 

100 times less lithium than 

the others. 

Lithium, a light element consist-

ing of three protons and four 

neutrons, was probably produced 

shortly after the Big Bang, 

13.7 billion years ago. Logically, 

it should be found in comparable 

proportions in most stars. But 

it would appear that the forma-

tion or presence of planets 

around a star leads the latter, 

by a mechanism that remains 

to be discovered, to destroy 

its lithium. This finding should 

certainly spur on the small world 

of exoplanet hunters, because the 

lithium deficiency of stars is now 

a serious indication of the pres-

ence of these extrasolar planets. 

  www.eso.org

A marine bacterium 

against cancer

The attention of Nereus Pharma-

ceuticals, a commercial company 

based in San Diego (US), and of 

biochemists at the Technical 

University of Munich (DE) has been 

drawn to a marine bacterium that 

goes under the Latin name of 

Salinispora tropica. This produces 

a molecule that could advanta-

geously replace the existing 

proteasome inhibitor drugs, used  

to prevent the proliferation of 

cancerous cells, but which cause 

serious side effects by also affecting 

healthy cells. 

Proteasomes are enzyme complexes 

that process the waste matter in 

cells. Disabling them condemns 

the cell to suffocate in its own 

residue. The Salinispora tropica 

produces a lethal molecule with 

an identical effect. It creates an 

opening in the proteasome, then 

blocks it, like a broken key in 

EUROPEAN NEWS

© I

nserm/C

atherine F

allet-Bianc

o

© ESO/L.C

alçada

© I

nserm/Jenn

y 

V

alladeau