emang co 2 keluar dari atas kepala kita ya....?
kok gak ngeh sih...?


On 3/26/07, Erik <[EMAIL PROTECTED]> wrote:

Moms & Dads,

Ternyata nyamuk bisa mendeteksi kita dari keberadaan gas CO2 yang
kita hembuskan saat bernafas. Makanya seringkali nyamuk menyerang
sekitar kepala kita.

Di bawah ini saya sertakan artikelnya.

Regards,
Erik

Mosquitoes target exhaled breath
http://news.bbc.co.uk/2/hi/health/6486057.stm

The mechanism mosquitoes use to zero in on their targets has been
discovered by scientists in New York.

It is already known that the insects are very sensitive to carbon
dioxide in exhaled breath.

Now a team led by Rockefeller University has found that they
sense the gas using protein receptors in the structure extending
from their jaws.

Writing in Nature, they say the discovery could aid the fight
against insect-born diseases, such as malaria.

The Rockefeller team first examined fruit flies.

They discovered two protein receptors, Gr21a and Gr63a, which
enable the fly to sense carbon dioxide with its antennae.

The researchers worked on fly nerve cells that did not normally
respond to carbon dioxide.

They found that, if the Gr21a and Gr63a receptors were both
switched on, the cells became excited by the gas.

They also showed that when Gr63a was mutated, the mutant flies no
longer responded to the high levels of carbon dioxide that wild
type flies avoid.

Assessing environment

The researchers went on to examine malaria mosquitoes and found
similar receptors in the insects' maxillary palp - a tiny
finger-like structure extending from the jaws.

Lead researcher Professor Leslie Vosshall said: "Insects are
especially sensitive to carbon dioxide, using it to track food
sources and assess their surrounding environment.

"The neurons in insects that respond to carbon dioxide were
already known, but the molecular mechanism by which these neurons
sense this gas was a mystery.

"Though we don't know what other proteins might be involved in
the signalling pathway, the identification of the carbon dioxide
receptor provides a potential target for the design of inhibitors
that would act as an insect repellent.

"These inhibitors would help fight global infectious disease by
reducing the attraction of blood-feeding insects to humans."

Dr Simon Hay, an expert in malaria at the University of Oxford,
said: "Curiously, the work could also open the opportunity for
the development of attractants, used to lure mosquitoes away from
humans.

"Increasing the distance mosquitoes have to fly for blood meals
has long been known to increase their mortality and thus decrease
disease transmission."



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