Features

Is it better to sterilise males with a dose of radiation or by inserting a gene?

That's part of the thrust of an article by Clive Cookson in the FT on the work of Oxford spinout Oxitec.

Of course what we are talking about are males of insect species that bring untold suffering to human populations around the globe.

The basic idea is simple: release large numbers of sterile males into infected areas so that they mate with all the available females who then produce no offspring.

But there's a problem: up until now the sterilisation has been achieved using radiation, but this doesn't work with the mosquitoes carrying dengue fever: unfortunately a dose high enough to render males sterile will kill or incapacitate them.

Now, in collaboration with Oxford scientists, Oxitec have found a more targeted way to sterilise male mosquitoes by inserting a 'dominant lethal' gene. 'The males produce viable sperm which will fertilise the egg, but the embryo [larva] dies in development,' said Oxitec's Luke Alphey, who left the University this year to work for the company full time.

So you get sterility AND virility.

It's an elegant solution which uses the antibiotic tetracycline to suppress the gene so that 'sterile' mosquitoes can be bred (remove tetracycline and any larva die). 

Of course many will baulk at the idea of unleashing a 'genetically modified flying army' into the wild. But, according to Luke, the gene can't 'escape' because the sterile males can't pass it on. 

The reaction of those in dengue-affected areas will be interesting. So far alternative approaches including insecticide fogging and improved sanitation haven't had much impact on the 100 million or so people afflicted by dengue every year.

If you lived under the threat of this disease would you be squeamish about releasing GM insects to destroy an insect species that is, in any case, alien to the region?

In a fascinating article in Scientific American Oxford's Gero Miesenbock explores the history of optogenetics - combining optics and genetic engineering to study specific types of cells.

Gero's particular interest is in combining genes that encode for cells that either emit or respond to light with neurons: in order to study brain circuitry.

He recently found a brain circuit in the olfactory system of fruit flies that produces noise - a discovery that has wider implications, as the basic architecture of a fruit fly's olfactory system is the same as a human's. Before that he had shown how stimulating the brains of fruit flies using a laser can cause female flies to perform a male courtship dance.

The Scientific American piece is well worth reading in full, but one particular point caught my eye when he goes on to discuss how the benefits of such research might one day impact on medicine:

'it would seem arbitrary and hypocritical to draw a sharp boundary between physical means for influencing brain function and chemical manipulations... In fact, physical interventions can arguably be targeted and dosed more precisely than drugs, thus reducing side effects.'

It's easy to fall prey to the understandable fear that physical interventions in our brains risk turning us into zombies or will-sapped cyborgs but are we all too easily overlooking the same risks associated with the drug cocktails patients routinely swallow?

I think we might look on such physical 'mind control' approaches differently if, in the future, they could offer relief from movement disorders such as Parkinson's, from debilitating behavioural disorders, and maybe eventually restore our lost senses.

As Gero comments, such direct approaches are still some way off. But right now optogenetics offers the promise of revealing new targets for drugs that could tackle anything from obesity to insomnia and anxiety.

Thanks to the work of Gero and others the 21st Century may genuinely turn out to be the 'Century of the Brain'.

It's easy to think there are two main roadblocks to saving wild habitats, apathy and money, but a new report into conservation in the Everglades suggests a third: bureaucracy.

According to New York Times the report suggests that Florida's unique 'river of grass' is rapidly reaching the point of no return. The gloomy prognosis is that a combination of human encroachment and delays caused by red tape mean that too many species will be lost before definitive action is taken.

NYT's Damien Cave writes that the long-term plan is for an environmental Florida purchase: 'negotiating a proposed $1.75 billion purchase of nearly 300 square miles of farmland from the United States Sugar Corporation to add storage space for millions of gallons of water south of Lake Okeechobee.'

For the Everglades ecosystem this purchase literally can't come soon enough. And if the US can't mobilise quickly enough to save a unique ecosystem on its own doorstep then what hope is there for poorer countries?

Reading about the brave efforts of the Army Corps of Engineers to realise the hugely ambitious Florida plans it makes me wonder whether we don't need some sort of environmental rapid reaction force - a green equivalent of UN peacekeepers - to bridge the gap between fast-moving environmental problems and the ability of governments to respond in time.

It might seem like the days when non-scientists could make big contributions to science are long gone but in fact we could be entering a new age of 'citizen science'.

I've blogged before about a variety of Oxford projects [including Galaxy Zoo and ClimatePrediction.net] in which scientists are collaborating with members of the public through the web.

Now a new initiative, The Encyclopaedia of Life (EoL), aims to harness people power to record biodiversity around the globe.

Charles Godfray from Oxford's Department of Zoology, a member of EoL's Distinguished Advisory Board, writes that 'its goal is to create a webpage for every species known to man.'

'EoL is developing the tools that will allow anyone to contribute to the project... [including] the more casual naturalist who might record a new locality for an animal or plant, or might submit a particularly nice photograph or biological observation.'

He comments that taxonomy has historically been an individualistic science but that if EoL can bring diverse observations, classifications and views on relationships between species together it will deliver massive benefits. 

Charles concludes: 'EoL offers the prospect of empowering this community to carry out novel and important biodiversity studies, and then for their findings to be incorporated into the ever-growing body of knowledge about the natural world.'

So the days of amateurs collecting specimens that advance scientific knowledge could be making a comeback, it's just that these specimens will be captured on a digital camera instead of in a jam jar.

Research published in PNAS this week reveals more about how a chemical compass could enable migrating birds to find their way.

‘Evidence is steadily accumulating to back up the idea that chemical reactions in the eyes of birds could help them navigate using the Earth’s magnetic field,’ says Peter Hore of Oxford's Department of Chemistry, co-author of the paper.

‘We have shown that a magnetic field has a small effect on the photochemistry of a protein called photolyase.'

Photolyase is closely related in terms of structure and properties to another protein found in birds’ eyes called cryptochrome which is thought to be at the heart of the compass sensor.

The results suggest that birds may ‘see’ the Earth’s magnetic field lines through variations in chemical reactions going on in their eyes. Such a compass could help them navigate during migrations.

Although the researchers used a magnetic field around 200 times bigger than that of the Earth, it is the first time a biological system closely related to that found in birds has been shown to be sensitive to a magnetic field.

The work is a collaboration between researchers at Oxford University, led by Dr Christiane Timmel and Professor Hore, and scientists at the Universities of Freiburg, Berlin and Munich.

The researchers previously reported that an artificial chemical system could detect weak magnetic fields and respond to their directions as a proof-of-principle of a chemical compass.

Peter told us: ‘It’s early days, but I feel that, if we get the conditions right in the lab, we will be able to see a larger effect and at weaker magnetic fields. That could mimic what happens in a migrating bird’s eye.’