Plant Sugars Provide Petrol

We all know that the days of fossil fuels are limited, so researchers are trying to find alternative fuels.  Biofuels have risen in popularity in recent years – fermenting plant material to make ethanol is already being used to produce fuel in several countries around the world.  But ethanol is a long way, chemically speaking, from the petrol (or gasoline for our US listeners) and diesel that are currently used in car engines.

The problem is that plant sugars have lots of oxygen atoms in them, which aren’t found in fuels like gasoline.  Now scientists at the University of Wisconsin-Madison have developed a biofuel that is identical, at the molecular level, to gasoline.  

Writing in the journal Science, the researchers have found a technique for turning complex plant sugars, called lignocellulose, into molecules that can be “upgraded” to make petrol, diesel and airplane fuel.  They do this by turning the plant sugars into molecules with fewer oxygen atoms, which can then be converted into high octane gasoline.

To create the new fuels, the scientists add a solid catalyst to a solution of the plant sugars. After a reaction, an oil-like substance is produced, that can be skimmed off the top of the solution. In this oil are acids, alcohols, ketones and other molecules, which are the precursors to gasoline. They can then be used in further reactions to make gasoline.

This is a much more efficient way of using lignocellulose for biofuels than previous techniques – the oil created by the team retains around 90% of the energy content found in the original sugars. Although this technique is still at an experimental stage, it might be the key to solving the oil crisis in the future.

21st Sep 2008

‘Baby’ Fat may Beat Obesity

It’s something that many of us struggle with – fat.  But where does it come from?  Researchers in Dallas have finally tracked down the location of immature fat cells, which hide out waiting for the extra calories that turn them into flab.

For a while, researchers have suspected that immature fat cells, known as progenitors, were hiding in or around the blood vessels that feed fatty tissues, but their precise location wasn’t known.  Working with mice, the researchers engineered fat progenitor cells with a gene that makes them glow green, so they could be followed in the body. They discovered that the progenitor cells are embedded in the walls of blood vessels that run through fatty tissues, and are an integral part if the vessel wall.

The researchers think that the cells are there because it enables them to sense the levels of nutrients in the blood.  When they get a whiff of excess calories, they can drift out of the blood vessels and mature into big fat cells.

The green label also meant that researchers could separate the immature fat cells from other cells, and grow them in the lab for further study.  The team hopes that they will understand more about the mechanisms behind fat growth, which could lead to ways to cut obesity and metabolic diseases such as diabetes in the future.  

As well as potentially helping people who struggle with their figure, the research could also point to ways to reactivate immature fat cells –for example, to fill in damaged tissues such as after injury or breast cancer surgery.

White Fat Progenitor Cells Reside in the Adipose Vasculature
Wei Tang, Daniel Zeve, Jaemyoung Suh, Darko Bosnakovski, Michael Kyba, Bob Hammer, Michelle D. Tallquist, and Jonathan M. Graff
Published online September 18 2008

21st Sep 2008

Personalised medicine – developing countries show the way

Increasingly, doctors are moving towards personalised treatment for diseases including cancer and HIV infection.  This means carrying out genetic tests to work out whether a person is likely to benefit from a specific treatment or not.  The idea is that people are more likely to get a treatment that will work, in a timely way, as well as saving money by not giving medicines that are unlikely to be effective.

You may think that countries like the UK or US might be leading the way in personalised medicine, but judging by a special supplement published in the journal Nature Reviews Genetics this week, developing countries are actually forging ahead and leaving the west behind.

Mexico, India, Thailand and South Africa are all leading the way in personalised medicine, also known as genomic medicine, which could have important lessons for other countries in similar circumstances. The programmes of genomic medicine in these countries are aimed at improving national health, cutting medical costs, and bolstering the economy.

In Mexico, scientists have captured the genetic makeup of more than 1,200 people from different regions of the country. This is feeding into research to look at the links between genetic makeup and diseases such as high blood pressure, obesity, infections, cancer, diabetes and heart problems.  Mexican experts believe that genomic medicine could cut diabetes-related healthcare costs by more than a third between 2010 and 2025.

In India, researchers found that the idea of personalised medicine stretches back more than 4,000 years, in the country’s Ayurvedic tradition.  Now a new genetic database contains information about 15,000 people from across the diversity of India.  According to some scientists, more than 10% of Northern India’s population don’t respond to up to 30 important drugs.  This is probably due to their genetic makeup, so understanding more about this could lead to better, more tailored treatments in the future.

Finally, in Thailand, researchers are looking for associations between genes and susceptibility to diseases such as malaria and dengue fever, while others are searching for links between genetic makeup and the likelihood of suffering post-traumatic stress disorder. While in South Africa, researchers are studying genetic diversity using samples from several indigenous tribes in Southern Africa.

21st Sep 2008

Fungi are world's fastest fliers

Scientists have discovered the fastest fliers in nature and, somewhat surprisingly, they're fungi!

Ohio-based researcher Nicholas Money and his colleagues at Miami University made the discovery by using ultra-fast cameras capable of taking 250,000 frames per second.  Down the lens they were studying members of two fungal families - the ascomycetes and the zygomycetes - that do the essential but unsalubrious job of breaking down animal dung.  These fungi rely on their spores passing harmlessly through the guts of grazing animals so that they land, quite literally, in the remains of their lunch.  But animals generally avoid grazing in areas where another animal has defaecated, leaving fungi like these with a problem.  Their solution is to have evolved the mycological equivalent of a "super-soaker" squirt gun - they fire their spores from tiny fluid-filled fruiting bodies so that they land in patches of uncontaminated grass ready for the next browsing ruminant.  But although scientists realised that the fungal launchpad must be incredibly powerful, it was too fast and too small to surrender its secrets, at least until now.

Writing in this weeks PLoS ONE the team have successfully made fungal ballistic measurements of spore trajectories to reveal that these organisms are firing their microscopic projectiles, which measure just a fraction of a millimetre across, at speeds exceeding 25 metres per second and at rates corresponding to 180,000 times the acceleration due to gravity.  This is sufficient to propel the spores up to 2.5 metres away from the parent dung pile.

The team were also able to get a handle on how the organisms achieve their fungal feat.  A concentrated mixture of sugars, alcohols and other metabolites inside the fungus and its fruiting body pulls in water by osmosis, priming the gun at a pressure about four times that of the atmosphere.  At the right moment the structure ruptures and the pressure drives out the spores.  According to the researchers the images of these fungal ejaculations are so pretty that they've set them to music and plan to post them on YouTube!