BBC Medical Science — Normally the immune system works out the difference between friend and
foe by looking for “foreign” surface proteins and, by cutting them
loose, the amoeba is able to stay undisturbed. …

The tiny creature behind tens of thousands of dysentery deaths each
year has a crafty method of slipping past our immune system, claim
researchers.

US scientists say amoebae can get rid of giveaway chemicals on their surface. The study in the journal Genes and Development suggests a similar technique helps malaria parasites get into human cells. …

It is suspected that the number of people infected by amoebae amounts to millions worldwide.

Most of them will never suffer bloody diarrhoea, which is the first
sign of amoebic dysentery, an infection which kills approximately
70,000 people each year.

In most symptomless cases, the body’s immune system eventually gets rid of the infection, but it can persist for years on end.

Researchers from Johns Hopkins and Stanford universities in the
US believe they have found out why the single-celled organism is
capable of evading the immune system for so long.

Existing research on the plasmodium malaria parasite revealed
that it used a type of cell chemical called a “rhomboid enzyme” to help
it get into the host cell.

A scan of the DNA of other parasites revealed the same chemical
in amoebae, and led to the discovery this chemical was capable of
getting rid of a protein called lectin found on its surface. (06/16/08)
more…

BBC Environmental Science – Progress towards developing a global
strategy to cut emissions is too slow, according to environmental group
WWF.

It issued its warning at the end of key UN talks that considered what
measures should replace the current set of climate targets, which
expire in 2012.

The group said the negotiations in Bonn had failed to make any progress
because nations were presenting “shopping lists, not blueprints” for
action.

The UN’s climate chief agreed that the process needed to become more focused.

The two-week gathering is part of a process that will culminate at a key conference in Copenhagen towards the end of 2009.

It is hoped that the summit in the Danish capital will see nations
agree on a new set of targets to reduce greenhouse gas emissions.

 
“Progress at the end of this second round in a series of UN climate
negotiations was considered feeble,” said Kathrin Gutmann, WWF’s
climate policy co-ordinator. The science tells us that governments need to think at a much
larger scale of action than ever before to get climate change under
control.”

Yvo de Boer, executive secretary of the UN Framework Convention
on Climate Change, agreed that the talks needed to become more focused. (06/16/08)
more…

BBC Science – Nasa’s Phoenix lander has provided the most magnified view ever of Martian soil.

Two
scientific instruments, a microscope and a “bake-and-sniff” analyser,
have begun inspecting soil samples delivered by the scoop on the
spacecraft’s robotic arm. …

It’s been more than 30 years since
a spacecraft has grabbed hold of the soil of Mars. In 1976, the two
Viking landers sampled the surface for signs of life. Soil on
microscope (Nasa) The scoop delivered soil to the lander’s microscope

Since
then there have been just three rovers on Mars, two of them still
trundling around. For them, the soil has been a road surface at best, a
sand trap at worst. It has not been a substance to pick up and handle.

Phoenix
has a much more sensual relationship with the planet’s surface. It is
digging furrows with its robot arm, stopping to collect a scoopful to
bring back to the instruments waiting impatiently on its deck.

But
we have little idea what the soil is like, and we’ve been fumbling
while we try to understand what we’re handling. There’s very little to
help us get a feel of the soil.

The three orbiters circling Mars
have sent back pictures at a level of detail never seen before of the
surface of the planet. We’ve looked down on ice-filled craters, canyons
that dwarf even the largest on Earth, and glimpsed Phoenix itself
swinging down on its parachute. That last image now forms the backdrop
to nearly every laptop screen at the science operations center (SOC).
But the orbiters can only give the most tenuous clues as to how the
soil might really feel. …

I’m back in the science operations
center (SOC) in Tucson just in time for the data to arrive back on
Earth. This time, the transmission stutters and we wait impatiently for
the full pictures to come down.

No one has looked at the dust of
Mars at this resolution before, and now I gasp as the images appear and
we see the sheer variety of what we have collected.

From tiny particles of the palest white to black rounded beads, we’re the first to see what coats Mars and makes the skies pink.

Zooming
in, we see finer and finer particles, right to the smallest grains that
our optical microscope can make out. We have run out of resolution and
that is why we have our atomic force microscope to look even more
closely at the dust. (06/16/08)
more…