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Scientists find key to malaria growth
Topic Started: 14 Nov 2015, 11:17 PM (56 Views)
skibboy
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Scientists find key to malaria growth

14 November 2015

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Mosquitoes are the primary vector for malaria

The key to malaria's rampant growth has been explained by scientists.

They say it is down to protein molecules called cyclins which cause cells to divide rapidly in the malaria parasite.

The study, led by a team from the University of Nottingham, could lead to new treatments for malaria, the researchers said.

Malaria is responsible for nearly half a million deaths a year.

A cyclin is one of the most important protein molecules needed for cell division.

They have been well studied in humans, yeasts and plants - but until now, little has been known about cyclins in the malaria parasite and how they affect cell development.

This research, published in the journal PLoS Pathogens, has been able to classify the number and type of cyclins present in malaria parasites.

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A human red blood cell infected with the malaria parasite plasmodium

Dr Bill Wickstead, from the University of Nottingham's School of Life Sciences, identified three different types of cyclin genes in the malaria parasite.

This is far fewer cyclins than are present in humans - and compared with other sets of cyclins, he said, they caused an "exciting type of cell division".

Prof Rita Tewari then carried out an in-depth analysis of a cyclin in the malaria parasite to find out more about what they do and why they do it.

She worked out that the cyclins found in malaria parasites made cells divide very quickly and enabled them to spread quickly in blood cells.

Working out why this happens could aid understanding of how the malaria parasite thrives within the mosquito and its human host, and lead to new treatments.

Dr Magali Roques, lead author of the study, said the research "will definitely further our understanding of parasite cell division, which I hope will lead to the elimination of this disease in the future."

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skibboy
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UK government sets up £1bn fund to fight malaria

22 November 2015

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Malaria is caused by a parasite spread by mosquitoes

The UK government is to create a new £1bn fund aimed at eradicating malaria and other infectious diseases.

The Ross Fund will be run in partnership with US philanthropists, Bill and Melinda Gates.

It is named after Sir Ronald Ross who became Britain's first Nobel Prize winner in 1902 for his discovery that malaria is transmitted by mosquitoes.

The number of people dying from malaria is falling but a child still dies from the disease every minute in Africa.

Ministers say the partnership with the Microsoft founder and his wife Melinda marks a "fundamental restructuring" of the UK's aid budget.

The £1bn will come from the UK's overseas aid budget over the next five years.

Of the total:

-£115m is earmarked for research into new drugs, diagnostics and insecticides for malaria, TB and other infectious diseases

-A further £188m will be spent on improving biodefences and rapid response systems to fast-spreading epidemics such as Ebola

Chancellor George Osborne said one billion people were infected with malaria and 500,000 children die from the disease each year.

He said the government's commitment to overseas aid helps to "promote our national security and interests around the world".

Working with the Bill and Melinda Gates Foundation will help us in "our joint ambition to see an end to this global disease in our lifetimes", he added.

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Insecticide-treated bed nets have helped to reduce cases of malaria

Mr Gates, co-chairman of the foundation, said eradicating malaria and other poverty-related infectious diseases would be "one of humanity's greatest achievements".

"With the combined skill and expertise of British scientists; leveraging the weight of both public and private financing; and the continued leadership of George Osborne and the UK, [the] announcement of the Ross Fund will play a key role in reaching that goal," he added.

The UK's International Development Secretary Justine Greening said a "healthy, prosperous world is in Britain's interest" and that preventing deadly diseases is a "smart investment".

The "restructuring" plan is expected to be set out by the chancellor in Wednesday's Autumn Statement.

The international development department is protected from cuts and has seen its budget increase year-on-year since 2010.

The government is expected to continue spending 0.7% of GDP on overseas aid.

A report published in the journal Nature earlier this year showed 663 million cases of malaria have been prevented in Africa as a result of concerted efforts to tackle the disease since 2000.

Researchers from Oxford University attributed the reduction mostly to bed nets. The drug artemisinin and spraying homes with insecticide also played a part.

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skibboy
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Mutant mosquitoes 'resist malaria'

By Michelle Roberts
Health editor, BBC News online

24 November 2015

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US scientists say they have bred a genetically modified (GM) mosquito that can resist malaria infection.

If the lab technique works in the field, it could offer a new way of stopping the biting insects from spreading malaria to humans, they say.

The scientists put a new "resistance" gene into the mosquito's own DNA, using a gene editing method called Crispr.

And when the GM mosquitoes mated - their offspring inherited the same resistance, PNAS journal reports.

In theory, if these mosquitoes bite people, they should not be able to pass on the parasite that causes malaria.

About 3.2bn people - almost half of the world's population - are at risk of malaria.

Bed nets, insecticides and repellents can help stop the insects biting and drugs can be given to anyone who catches the infection, but the disease still kills around 580,000 people a year.

'Pivotal role'

Scientists have been searching for new ways to fight malaria.

The University of California team believe their GM mosquito could play a pivotal role - breeding resistant offspring to replace endemic, malaria-carrying mosquitoes.

They took a type of mosquito found in India - Anopheles stephensi - on which to experiment.

Dr Anthony James and his team showed that they could give the insect new DNA code to make it a poor host for the malaria parasite.

The DNA, which codes for antibodies that combat the parasite, was inherited by almost 100% of the mosquito offspring and across three generations.

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Mosquito larvae can be genetically modified to carry 'useful' new genes, such as resistance to the Plasmodium parasites that cause malaria

The researchers say the findings offer hope that the same method could also work in other mosquito species.

Although it would not be a sole solution to the malaria problem, it would be a useful additional weapon, they say.

Prof David Conway, UK expert from the London School of Hygiene & Tropical Medicine, said: "It's not the finished product yet but it certainly looks promising. It does look like the genetic editing works."

Other scientists have been looking at genetically modifying mosquitoes to render them infertile, so that they die out.

But some experts fear that eliminating mosquitoes entirely may have unforeseen and unwanted consequences.

Replacing disease-carrying mosquitoes with harmless breeds is a potential alternative.

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skibboy
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Scientists create infertile mosquitoes

By Michelle Roberts
Health editor, BBC News online

8 hours ago

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Malaria is caused by a parasite, called Plasmodium, transmitted by female mosquitoes when they bite people

UK scientists say they have reached a milestone in the fight against malaria by creating a genetically modified mosquito that is infertile.

The plan is to wipe out the insects that spread malaria to people via bites, Nature Biotechnology reports.

Two copies of the mutant gene render the malaria-carrying female insect completely barren.

But one copy is enough for a mosquito mum or dad to pass it on to offspring.

This should perpetually spread the infertility gene throughout the population so the species dwindles or dies out.

However, the Imperial College London team say more safety tests are needed, meaning it will be a decade before the mutant mosquitoes can be released into the wild.

Cheating nature

The mutant mosquito can still carry and transmit malaria to people via bites.

But their genetic make-up means they should breed with and replace other malaria-carrying mosquitoes.

Any offspring with one copy of the gene would carry on passing the trait to future generations, while any female offspring that inherits both copies would be unable to reproduce.

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Mosquito eggs

In this way, the host of the malaria parasite should eventually become extinct.

In the Imperial team's experiments with Anopheles gambiae - a breed of mosquito that is rife in sub-Saharan Africa where the bulk of human malaria deaths currently occur - the mutant mosquitoes were kept with wild-type ones so they could mate.

The gene for infertility was transmitted to more than 90% of both male and female mosquitoes' offspring across five generations, thanks to technology called gene drive, say the researchers Dr Tony Nolan and Prof Andrea Crisanti.

Normally, one copy of a recessive gene has a 50% chance of being passed down from parents to their offspring.

Gene drive - a DNA cutting and pasting machine that can manipulate genetic code as it is passed from parent to offspring - boosts this inheritance rate.

Wipe out

Some experts fear that wiping out mosquitoes may upset the natural balance of the environment.

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But Prof Tony Nolan said their method should not make a big dent in the overall mosquito population - just the ones that transmit malaria.

"There are roughly 3,400 different species of mosquitoes worldwide and, while Anopheles gambiae is an important carrier of malaria, it is only one of around 800 species of mosquito in Africa, so
suppressing it in certain areas should not significantly impact the local ecosystem."

Prof David Conway, an expert in malaria at the London School of Hygiene and Tropical Medicine, said the work held promise: "The key achievement here is that a novel genetic drive mechanism can force these modifications to be passed on, using a trick that would not occur in nature."

But he said more work was needed to check that the mosquitoes don't evolve resistance to the genetic modification.

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