Newsgroup: it.scienza.ambiente
Titolo: zanzara transgenica

Guardate cosa ho trovato su un altro Ng....qualche commento (solo
scientifico please!)?
Transgenic Mosquito Could Mean Eradication Of Malaria
The prospect of eliminating malaria moved one step closer today with the
announcement that European scientists have created the world's first
transgenic
malaria mosquito.
Scientists at Imperial College, London, and the European Molecular Biology
Laboratory, Heidelberg, report in Nature today how they have successfully
inserted a foreign marker gene into the mosquito genome.
This means that transmission of the disease could be controlled through
manipulation of mosquito genes by disrupting the insect's interaction with
the
malaria-causing parasite, by altering its choice of blood target from man to
animal, or by selectively creating sterile male mosquitoes.
The authors are unanimous in their view of the great potential this
development
has for combating malaria. Dr. Andrea Crisanti of Imperial College, a senior
author of the paper, said, "We now have the ability to target specific genes
that will allow us to genetically alter the mosquito to stop it spreading
malaria."
"We think that within six years a mosquito will be created that is stable,
safe
and physically unable to transmit the malaria-causing parasite," he added.
"After 15 years of trying to create a transgenic mosquito we have taken a
major
step forward. This is not a cure for malaria, but we now have the key
missing
tool -- our holy grail. The development of this technique is crucial for
scientists studying the biology of the mosquito and its interactions with
the
malaria-causing parasite."
Dr. Crisanti outlined possible ways in which malaria may be controlled using
a
transgenic mosquito: "We could create an environment within the mosquito
that
prevents the malaria-causing parasites from living there. We could alter the
behavior of the mosquito so it prefers animal rather than human blood, or we
could produce sterile male mosquitoes to lower the mosquito population."
The researchers borrowed gene transfer technology successful in another
species, the fruit fly Drosophila, and adapted it to work in the mosquito
species Anopheles stephensi.
"Although this technology is well established in Drosophila, it was thought
that it couldn't be done in the mosquito," said Dr. Crisanti.
Other transgenic insects which have been successfully created and introduced
to
the environment to control pests or disease problems include the
Mediterranean
fruitfly (Ceratitis capitata) and the Screw-worm fly (Chrysomya bezziana).
The
release of screw-worm flies which had been genetically modified to produce
sterile males has already been shown to be successful in the eradication of
the
insect from North and Central America and Libya.
A major problem the team overcame in their research is that freshly-laid
mosquito eggs harden very quickly, making micro-injection of the new genes
very
difficult. Only after discovering a compound which slows down the rate of
hardening and does not interfere with the development of the mosquito embryo
could they proceed to physically insert the foreign genes.
The transgenic mosquito the team developed was made to carry an extra gene
that
produces a green fluorescent protein. This protein is used because it acts
as a
highly visible marker (under ultraviolet light) to indicate which mosquitoes
have successfully incorporated the foreign genes.
Dr. Carlos Morel, Director of the UNDP/World Bank/WHO Special Programme for
Research and Training in Tropical Diseases, welcomed the news: "The
announcement of stable germ line transformation of Anopheles mosquitoes
represents a major breakthrough in the field of molecular entomology."
"The transformed 'green mosquitoes' now signal a 'green light' for more
serious
investment in the development of new approaches for malaria control," he
said.
Dr. Crisanti added: "It is hard to find money for research on diseases of
the
developing world so we are very grateful to our sponsors: Implyx, the World
Health Organisation and the European Community, without whom this goal would
not have been achieved."
Co-authors of the article include: Flaminia Catteruccia, Tony Nolana,
Thanasis
G. Loukerisb, Claudia Blassb, Charalambos Savakisc, Fotis C. Kafatosc and
Andrea Crisantia.
Imperial College of Science, Technology and Medicine is an independent
constituent part of the University of London. Founded in 1907, the College
teaches a full range of science, engineering, medical and management
disciplines at the highest level. The College is the largest applied science
and technology university institution in the UK.
Imperial College of Science, Technology and Medicine
Malaria factsheet
According to the World Health Organization, there are up to 500 million
clinical cases of malaria each year, resulting in approximately 2.7 million
deaths.
The disease is responsible for over a million deaths every year mainly among
young children in Africa. It is one of the top priorities of the World
Health
Organization.
The malaria situation around the world is worsening. Plasmodium falciparum
has
become resistant to the most common antimalarial drugs in most of its area
of
distribution. Mosquitoes are also becoming more resistant to chemical
insecticides.
Biology of the disease
Malaria is a tropical disease characterized by cyclical bouts of fever with
muscle stiffness, shaking and sweating.
It is caused by a tiny parasite (genus Plasmodium) that is only transmitted
by
the female mosquito (genus Anopheles) when it feeds on blood for its
developing
eggs. The parasites move to the salivary glands of the mosquito and are
injected into a human host by the feeding insect.
Humans are generally host to four species of malaria parasites: Plasmodium
falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae.
Plasmodium falciparum is the most virulent and potentially lethal to humans.
The threadlike malaria parasites enter the bloodstream and are carried to
the
liver, where they invade liver tissue cells, transform into spores and
replicate repeatedly.
The spores are released into the bloodstream where they attack and destroy
red
blood cells. The process is repeated until natural or acquired immunity,
antimalarial chemotherapy, or death brings the repetitive process to an end.
[Contact: Dr. Andrea Crisanti, Dr. Taslima Khan ]
22-Jun-2000
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scientifico please!)?
uhm....
non entro nel merito del transgenico si/transgenico no, tanto di cose
se ne dicono gia' tante...
piuttosto mi e' venuta in mente un'altra cosa: una delle strategie
proposte e' la diffusione di insetti che producano una progenie
maschile sterile, ma puo' funzionare?
La semplice selezione naturale dice che se un maschio non procrea una
prole feconda, i suoi geni, transgenici o no, non si trasmettono,
quindi gli effetti dell'introduzione delle zanzare transgeniche
durerebbe una sola generazione... in termini di zanzare temo che sia
meno di una stagione....
^_^
Scy

 Scy
Hai ragione... forse cercheranno di "far diventare" le femmine
partenogenetiche? Però poi le zanzare potranno dire addio a una veloce
evoluzione, mancando il rimescolamento fra cromosomi padre/madre.
Ma penso che fra qualche tempo ne vedremo delle belle....

or by selectively creating sterile male mosquitoes.
e qui ha già risposto Scytale, anche se mi dovrei andare a rivedere
qualche appunto di genetica. Anzi, ora vado a rispondere anche a lei.
La mia paura è come sempre legata all'ingegneria genetica (non sono
mai stato un tipo coraggioso), che cmq va a cambiare qualcosa nel
delicato equilibrio della natura. Tutto sta a vedere come va a finire
la sperimentazione, se la zanzara-robot :)) andrà a competere in modo
decisivo con quella "naturale" (in sostanza il problema è questo), e,
se competitivamente vincente, altererà qualche meccanismo naturale che
possa rivelarsi poi dannoso per l'uomo o l'ambiente. Insomma, per non
trovarsi poi in uno scenario tipo "I Corvi" di Hitchcook (si scrive
così?) ;))))
Soprattutto bisognerebbe sapere se la mutazione indotta ha la
possibilità di alterare la fisiologia della zanzara rendendola in
qualche modo più pericolosa (pensate alla zanzara-tigre).
Certo che ora, tra zanzare innocue, patate curative e chi più ne ha
più ne metta, di naturale è rimasto ben poco ......
Ciao Ciao
AleX  -  non ho continuato per non dilungarmi troppo

Scy
Ciao Ciao
AleX

 ha scritto nel messaggio
news:qGWiOfy6FsgZ9tMWj+KSWwq2=5...@4ax.com...

...Se fanno tutto sto casino solo  per estinguere la specie, poi il
plasmodio non si troverà un altro ospite intermedio, magari un'altra specie
di zanzara?
Pensavo volessero solo far cambiare abitudini alla "povera bestiolina"!:))
Vabbè, stiamo un pò a vedere che succede!
Ciao.

Ciao.
Ciao Ciao
AleX

Hitchcock

Hitchcock
L'ignoranza non ha mai fine :(((
AleX


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