Features

With Halloween almost upon us we thought we should give you a scare of the eight-legged variety.

So I asked George McGavin, of the Oxford University Museum of Natural History, about scary spider encounters and why arachnids deserve gasps of wonder along with our yelps of fear...

OxSciBlog: What has been your favourite encounter with a spider?
George McGavin: My favourite encounter has got to be when I found the goliath bird-eating tarantula (Theraphosa blondi) when filming Lost Land of the Jaguar in Guyana. We went out after dark to scour the forest close to base camp - after several hours we had not found anything and I was beginning to think that we'd never find one when Bruds, one of the rangers, radioed to say he had found a likely burrow.

Sure enough the burrow was occupied by a large female which I was able to coax out using a blade of grass as a lure. Once in the open I blocked the hole with my machete. The spider was the size of a soup plate and although equipped with half inch long fangs, their main defence is to flick tiny harpoon-like hairs in the face of any attacker. This she did with great enthusiasm and the air was soon filled with her abdominal hairs. They got in my face, eyes and throat but I was not going to be deterred.

When she had calmed down I gently picked her up to show to the camera. She was a real star and even leapt off my hand towards the cameraman - a great performance!

OSB: In evolutionary terms how successful are spiders?
GMcG: Arachnids appeared on Earth around 420 million years ago. Today there are about 80,000 species worldwide. They are a very old group and include things like mites, ticks, scorpions, whip-spiders, harvestmen and pseudoscorpions. The true spiders have mastered the use of silk for prey capture, transport, protection and other uses.

OSB: How important are spiders to preserving ecosystems?
GMcG: As terrestrial carnivores arachnids they have a huge impact on populations of insects and other small invertebrates. A hectare of grassland may be home to several million spiders and other arachnids. One species lives in water in a specially constructed silk diving bell and can prey on small fish fry. Recently the first herbivorous spider has been discovered.

OSB: Why do you think many people have a fear of spiders?
GMcG: In the UK 7 million people are arachnophobic to some degree. While it is true that there are a dozen or so species of spiders whose fangs are strong enough to break human skin they will not do you any harm and allergic reactions to spider bites are very rare.

In Australia, however, where there are several dangerous species, people seem a bit more relaxed about their eight-legged friends. In the middle ages in Europe spiders were associated with diseases and death and I wonder if this might be might origin of our phobia.

OSB: What do scientists still need to find out about spiders?
GMcG: While the arachnids are not as diverse as the insects there are still many more species waiting to be discovered. We actually know very little about the lives of most spider species.

 Dr George McGavin is an Honorary Research Associate at the Oxford University Museum of Natural History. 

Tiny flashes of blue light from beneath the icy South Pole could help scientists uncover the origins of cosmic rays and neutrinos.

These flashes occur when neutrinos created by cosmic rays strike nuclei in the ice, releasing energetic muons which travel through the ice faster even than light can -  producing a burst of Cherenkov radiation. This is detected by IceCube, a 'telescope' made up of thousands of optical sensors buried up to 2.5km deep in the Antarctic icecap. This location is ideal because under the huge pressure at such depths the ice is free of air bubbles and very clear.

Subir Sarkar of Oxford University's Department of Physics leads the British involvement in IceCube, he told The Telegraph's Richard Gray: 'Cosmic rays were discovered 100 years ago, but we still have no idea where they come from. At first glance, IceCube seems like a crazy experiment. How can you study the sky when you bury your detectors a mile beneath the ice? But it gives us a new way of tracing their paths back to their source.'

'The real excitement is that neutrinos and cosmic rays will reveal an entirely new way of looking at the universe and allow us to see into places where we haven't been able to before.'

'Currently we have no way of peering into black holes through the dust and gas that surrounds them, so if high energy neutrinos are being emitted from their fringes, then we can 'see' into places we haven't been able to before.'

IceCube isn't due to be completed until 2011, when all the optical sensors will have been installed, but as early as 2006 its detectors began to pick up the flashes of neutrino collisions. It's already identified an area of the sky near the constellation of Vela as a prolific source of cosmic rays.

Being able to spot these very rare neutrino collisions could help us understand the nature of the dark matter thought to make up around 23% of our Universe.

Normally we think of metals in our water supply as a bad thing, but when it comes to trace amounts of metals welling-up from the ocean’s depths we should count ourselves lucky that they appear.

That's because metals such as iron and zinc are essential to all kinds of marine life – they act rather like a 'fuel' that powers ocean ecosystems. On 17 October an Oxford University-led expedition will set sail for the South Atlantic to study these ‘micronutrient’ metals.

'Because they are present in seawater at such low concentrations they are difficult to measure but with this new expedition we hope to revolutionise our understanding of the metal 'micronutrient' cycle and gain insights into the past, present and future of Earth's climate,' explains Gideon Henderson of Oxford University’s Department of Earth Sciences and the Oxford Martin School, who is leading the UK-GEOTRACES consortium.

Gideon will lead a team of 24 scientists from 10 UK institutes aboard the Royal Research Ship Discovery, one of NERC’s research vessels, collecting samples and carrying out experiments on the 39-day cruise from Cape Town to Montevideo.

The RRS Discovery will head to the South Atlantic where the ocean is particularly rich in life, but where the sources of micronutrients are a mystery. By collecting samples, and making a wide range of measurements both on board and back in the lab, the research team hopes to learn how the metals enter and leave the ocean, and how their abundance in seawater influences marine biology.

Much of our understanding of past climate comes from measurements of marine sediments but understanding how climate information is reflected in the chemistry of the sediments is essential if we are to interpret this evidence correctly.

Understanding the cycle is also vital if we are to assess whether proposed geo-engineering schemes, such as 'seeding' the oceans with iron to increase their carbon uptake, might work.

'Changes in marine ecosystems also have a wider impact: these ecosystems are vital for food production, biodiversity, international development, tourism, and pollution management,' Gideon tells me.

'Any changes in the cycling of micronutrients in the South Atlantic will have an impact not just on the local area but also on the natural resources, economies and standard of living of countries around the world.'

UPDATE: Read regular updates of the mission's progress on the UK-GEOTRACES blog.

Tumours seem to pacify our immune system by tapping into our bodies’ codes, but we may be able to use this trick against them in our bid to hunt them down.

Melanomas are not only one of the most aggressive types of human tumours but the cancerous cells are able to survive and proliferate despite the body’s best efforts to destroy them. Professor Vincenzo Cerundolo, Director of the MRC Human Immunology Unit at the University of Oxford, has been trying to establish how melanomas survive these attacks.

Our bodies are continuously fighting off infections and invading cells. We have many methods of defence at our disposal as part of our immune system - a huge, highly organised army complete with different types of troops and manoeuvres.

The ranks include a particularly potent type of cell called a neutrophil. Neutrophils are packed full of powerful enzymes that can destroy cells at the same time as recruiting reinforcements to the area (inflammation). But, as in any battle, there are always fears over friendly fire so the immune system can quickly issue messenger proteins that revert the troops to being passive so they don’t damage the body’s own cells.

The problem is that, as with any code used in war, the enemy can crack it. Vincenzo’s team recently discovered that melanomas have done just that as they also produce the messenger protein that signals inflammation to stop.

The protein concerned is called serum amyloid A (SAA) and it switches neutrophils from being aggressive to being anti-inflammatory. In other words, the melanomas seem to have evolved a way to manipulate the body’s own safety mechanisms so that they aren’t destroyed.

Unfortunately for melanomas though, producing anti-inflammatory neutrophils isn’t the protein’s only effect. The latest work from Vincenzo’s group, published in Nature Immunology, shows that SAA also affects another type of immune cell called an invariant natural killer T cell (iNKT) where it has exactly the opposite effect, jumpstarting the immune response  by activating antibody-producing cells  (B lymphocytes) and recruiting more cells capable of destroying tumours and virus infected cells (Killer T lymphocytes).

Vincenzo explains that 'SAA is used in the body to fine-tune the immune system, keeping the body alert to attack but stopping it from doing any unintended damage. The question of how melanomas can beat the immune system's defences has been asked for a really long time, and melanomas have many tricks up their sleeves, but we think their use of this protein is a really important one. But finding out that SAA also interacts with these iNKT cells was a really unexpected result and it means there’s a possible way of restoring the anti-tumour immune response.'

In healthy people the number of neutrophil cells is already an order of magnitude above iNKT cells, but in cancer patients there are even fewer iNKT cells to attack the tumours. Vincenzo says, 'it’s very early days but there are drugs that can promote activation of iNKT cells which we might be able to use to get patients’ immune systems to fight back.'

'Our bodies are set on the slightly cautious side as we don’t want our immune systems to damage the healthy parts of our body, but if we know what we’re doing we could activate the immune system in the places and at the times that we need it. SAA is secreted during inflammation from any acute or chronic problem such as influenza or arthritis. If we can manipulate iNKT cells sufficiently it could be a very exciting prospect indeed, not just for cancer but for many other inflammatory diseases.'

Researchers from Oxford University are well represented on the Eureka 100: a list of the most important contemporary figures in British science.

The list, compiled by The Times to celebrate the first anniversary of its science magazine Eureka, features 11 Oxford figures from all areas of science.

The highest entry goes to Jocelyn Bell Burnell [15], after her comes John Bell [20], then Richard Dawkins [25], followed by Kay Davies [29]. Breaking into the 40s and 50s are Andrew Wiles [41] (arriving in 2011) and David King [54] whilst the 60s and 70s sees a run of prominent Oxford scientists: Peter Ratcliffe [60], Colin Blakemore [64], Graham Richards [65] and John Krebs [71]. Last but not least, friend of OxSciBlog Marcus du Sautoy [76] makes it a bumper crop of research talent.

One thing's certain: it's sure to generate plenty of discussion about who made the list and who didn't, and how you measure the influence of scientists, at a time when the role of British science is under the microscope. And that can only be a good thing.

Let us know which Oxford scientists not featured above should have been on the list and why by adding a comment below.