Podcast Transcript

Biofuels could spell bad news for the oceans

Debate ranges on over how to solve the problem of global emissions of carbon dioxide from burning fossil fuels. A new study has shown that if we’re not careful, growing crops to turn into biofuels could spell disaster in the sea by worsening so-called ‘marine dead zones’ where wildlife is wiped out by depleted oxygen levels.

When fertilisers are applied to agriculture land – including onto biofuel crops – much of it washes into coastal waters where it triggers blooms of algae. The algae eventually die and sink to the sea floor where bacteria break them down, using up oxygen in the process.

Because of this, every year, a huge and growing area of sea become anoxic and unable to support life. In 2008, the dead zone in the northern Gulf of Mexico was more than 27,000 km2 – that’s over half the size of England.

Christine Costello and W. Michael Griffin and colleagues from Carnegie Mellon University and the University of Pittsburgh in the US, have developed a computer model of the Gulf of Mexico to predict what is likely to happen if more biofuels are planted – something that the US federal government are pushing for in at attempt to tackle climate change. The target is for 36 billion gallons of biofuels to be produced each year by 2022.

To meet this biofuel target, no matter what crops are planted – even grasses that need less fertiliser– it will lead to a massive increase in the amount of nitrates reaching the Gulf of Mexico and a worsening of the dead zone.
Biofuels will no doubt remain a popular option for reducing our carbon dioxide production, but this study emphasizes the need to consider all the consequences that might have on the environment.

The authors point out various options for reducing the impacts of nutrient runoff from agricultural land, including planting strips of vegetation along riverbanks – so-called Vegetative Buffer Strips – as well as constructing areas of wetland and the very precise application of fertilisers.

If crop-based biofuels hold any hope as the sustainable green solution of the future, these are the sorts of things that need to be promoted.

20th Sep 2009

Green tea help bones grow

If you are a tea addict – like Helen – and you fancy a health boost in your daily cuppa, than you could do a lot worse than reach for a swig of green tea, apparently one of the world’s most popular drinks.

Along side all the other potential health benefits it comes with – it is allegedly good for our hearts, it has anti-cancer properties – it now seems that compounds found in green tea are good for bones too.

Ping Chung Leung and colleagues from the Chinese University of Hong Kong have been looking at the affects on bone cells of a trio of compounds called catechins that are found naturally in green tea.

By exposing cultures of bone-forming cells from rats – called osteoblasts – to these green tea compounds, the researchers found that both the rate of bone growth and bone strengthening was significantly increased within a few days.

Some of this bone boosting affect comes down to the activity of a key enzyme that promotes bone growth. One particular green tea compound called Epi- gallo-catechin (EGC), led to an increase in this enzyme’s activity by 79%.  It also increased levels of bone mineralization in these cells: a vital part of strengthening bones.

EGC also suppressed the activity of cells called osteoclast cells that weaken and break down old bone, part of the natural process of bone remodelling.
These studies were conducted on rat bone cells, so further research is need to see if the same affect will hold true for human bone cells.

What’s more, the study, appearing in the journal of Agriculture and Food Chemistry, doesn’t mention how the doses of catechins used relate to the amounts found in a cup of green tea. It is also not clear whether it would have any affect on your bones when the liquid has passed through your digestive system.

Nevertheless, earlier studies have hinted at the real benefits of drinking tea, for example it’s been shows that postmenopausal women who are regular tea drinkers tend to also have denser bones.

And this study certainly points towards a potential new approach to treating bone conditions like osteoporosis if the activity of those catechin compounds can be harnessed. And it just goes to show, that sipping a daily cup of green tea, is not just tasty and refreshing, but it may well be doing us some good too.

20th Sep 2009

New prostate cancer genes found

Scientists at the Institute of Cancer Research and the University of Cambridge, funded by Cancer Research UK, have made another important addition to our knowledge about the genes involved in prostate cancer.  They've discovered nine new gene variations that can increase the risk of the disease by around three-fold, published in two papers in the journal Nature Genetics today (Sunday 20th September). And, excitingly, some of the new genes could be potential targets for future cancer drugs.

This is yet another example of  a genome-wide association study involving an international team of scientists.  Researchers scan through the DNA of thousands of people using the latest genomics technology. They're searching for tiny differences in the DNA sequence between people with cancer, and people without the disease.  Eventually, the scientists narrow the search down to a few small regions, and can pinpoint the genetic variations that might increase the risk of the disease.

In total, in the first study, the researchers looked at DNA from almost 38,000 men, trawling through over 43,000 SNPs, or single nucleotide polymorphisms. These are tiny variations in our DNA. They discovered seven regions of DNA that are linked to prostate cancer risk – and two of them are in genes that could be promising targets for treatment.

In the second study, the scientists focused in on a region on human chromosome 8, which has previously been linked to prostate cancer risk.  Their detailed investigation revealed two new variations involved in the disease. Altogether, we now know of more than 20 regions of the genomes that are linked to prostate cancer risk.

These are subtle variations in our DNA that influence risk, but don't determine that someone definitely will – or won't – get cancer. Our genes are like a hand of cards – most of us get a mix of good and bad cards (risky or non-risky gene variations) and it depends how we play our genetic “cards” through our lifestyle that affect our cancer risk.  

More research needs to be done, but this new genetic information could help doctors to tell who is at most risk of prostate cancer, and offer surveillance or screening, or help to tell if a cancer is likely to be aggressive. And it provides important new clues for the development of future treatments for the disease.

20th Sep 2009

The robot doctors are coming!

Robot surgery research is definitely taking off – for example, surgeons can do keyhole surgery on patients even if they're in a different country. Now new technology is improving compatibility  between robot systems, allowing doctors to use the internet to operate surgical robots all over the world.

Scientists have developed a new piece of software called the “Interoperable Telesurgical Protocol”, which is designed to standardise the way that robotic surgeons are operated over the internet. To test it out, nine research teams from around the world used it to operate a robot surgeon. The scientists were in different locations in the US, Europe and Asia.

Over 24 hours, each group connected over the Internet and controlled robots at different locations, testing how different robot and controller designs can be operated through one system. This is very important, because it means that researchers who may use slightly different robots and systems can all work together.  

The researchers hope that future developments in robot surgery will use the new protocol, to enhance compatibility with researchers around the world. Unfortunately, it's not much help if the internet goes down...

20th Sep 2009

This week in science history - The discovery of Ötzi the Iceman

This week in science history saw, in 1991, the discovery of Ötzi the Iceman in the Ötztal Alps between Austria and Italy. His body is the oldest naturally preserved mummy found in Europe and due to the excellent preservation, he has told us much about Copper Age people.

On the 19^th of September 1991, Helmut and Erika Simon, a German couple, were hiking on the Schnalstal glacier when they made a gruesome discovery. After reporting what they assumed to be the body of a modern unfortunate tourist or rock climber, the authorities made several bungled attempts to remove the body from the ice. They broke the arm of the body, punctured its hip with a jackhammer and managed to rip the clothing around the body. Eventually they freed the body from the ice and took it to a local morgue. Six days after the discovery, an archaeologist was brought in, and after examining the clothing and artefacts, such as the axe, found with the body he concluded that it was at least four thousand years old. It was only after carbon-14 dating of the body by four different institutions that the age of the body was determined. Ötzi, as he was named, after the mountains in which he was found, was born and died some time between 3300 and 3100 BC.

To put this in perspective, this is between 500-800 years before the Great Pyramid at Giza was built and around 600 years before Stonehenge.

The period Otzi lived in is known as the Copper Age or Chalcolithic period, between the Neolithic (or Stone Age) and the Bronze Age from around 3500 to 1700 BC. Society was already relatively sophisticated in Europe at this time. People had been living in permanent settlements for at least a thousand years and had domesticated crops such as barley, flax and peas as well as animals like goats and sheep. With the start of copper mining and smelting, several changes occurred. Trade of copper ore and pure copper, as well as artefacts such as jewellery and weapons began, bringing wealth to the areas where the ore was mined. The appearance of sophisticated copper weapons suggests conflict between settlements over resources and the need to protect them. The domestication of horses around this time would have helped with transportation. Otzi himself had in his possession a copper axe, the most complete and best preserved example we have. It would have remained sharper for far longer than a flint axe, and so would have been very valuable. Among other items he carried birch bark containers to carry fire embers, a bow and quiver of arrows, a flint dagger and a net for catching birds and rabbits, all of which are incredibly well preserved given that they are over 5 thousand years old.

Since the discovery of his body, we have been able to learn a lot about Otzi. The truly remarkable thing about him is his level of preservation. The freezing temperatures and remote location up on the glacier meant that there was very little degradation of the body by bacteria and animals. His stomach contents was analysed and we know his last meal involved deer meat, vegetables and fruit and possibly some sort of bread. Pollen analysis, or palynology, has also proved a fascinating tool. The shape of pollen grains is unique to each family of plants – it is easy to tell grass pollen from birch or hawthorn pollen, and it tends to be very well preserved due to the robust cell walls in the pollen. The evidence from the pollen in Otzi’s digestive tract has told us that Otzi lived in one of the local valleys, ate his last meal in a conifer forest, presumably on his way up the mountain and even that he died in spring.

How he died has been under debate ever since his discovery, but in 2001 it seemed that the debate might have been resolved. During an X-ray of the body, a flint arrow head was discovered embedded in his left shoulder. Further exploration of the wound showed it had severed a major artery and paralysed the left arm. There was also evidence of trauma to the skull and a brain haemorrhage, possibly from a fall after being shot with the arrow. Evidence of cuts and bruises on his hands and arms suggested a struggle in the lead up to his being shot, although the jury’s still out on what this fight might have been over. It is now assumed that the arrow wound and/or the head injuries caused his death.

Otzi’s body is on display at the South Tyrol Museum of Archaeology in Bolzano, Italy, along with his possessions. The discovery was hugely important for anthropologists studying that period in European human history as it’s not a period where we have written records and so we have to rely on evidence from burial grounds and sites of villages to learn about the people and their way of life. Evidence from Otzi’s stomach contents, his bones and his skin, combined with the sophisticated possessions and tools he had with him have allowed us to learn much more about the everyday lives of European people over 5000 years ago.

September 2009