Monday, 21 July 2008

Weekly BioNews 14 - 21 Jul 2008

- Fuel from food waste: bacteria provide power

July 19, 2008 10:50 AM

Researchers have combined the efforts of two kinds of bacteria to produce hydrogen in a bioreactor, with the product from one providing food for the other. According to an article in the August issue of Microbiology Today, this technology has an added bonus: leftover enzymes can be used to scavenge precious metals from spent automotive catalysts to help make fuel cells that convert hydrogen into energy.

Hydrogen has three times more potential energy by weight than petrol, making it the highest energy-content fuel available. Research into using bacteria to produce hydrogen has been revived thanks to the rising profile of energy issues.

We throw away a third of our food in the UK, wasting 7 million tonnes a year. The majority of this is currently sent to landfill where it produces gases like methane, which is a greenhouse gas 25 more potent than carbon dioxide. Following some major advances in the technology used to make "biohydrogen", this waste can now be turned into valuable energy.

"There are special and yet prevalent circumstances under which micro-organisms have no better way of gaining energy than to release hydrogen into their environment," said Dr Mark Redwood from the University of Birmingham. "Microbes such as heterotrophs, cyanobacteria, microalgae and purple bacteria all produce biohydrogen in different ways."

When there is no oxygen, fermentative bacteria use carbohydrates like sugar to produce hydrogen and acids. Others, like purple bacteria, use light to produce energy (photosynthesis) and make hydrogen to help them break down molecules such as acids. These two reactions fit together as the purple bacteria can use the acids produced by the fermentation bacteria. Professor Lynne Macaskie's Unit of Functional Bionanomaterials at the University of Birmingham has created two bioreactors that provide the ideal conditions for these two types of bacteria to produce hydrogen.

"By working together the two types of bacteria can produce much more hydrogen than either could alone," said Dr Mark Redwood. "A significant challenge for the development of this process to a productive scale is to design a kind of photobioreactor that is cheap to construct and able to harvest light from a large area. A second issue is connecting the process with a reliable supply of sugary feedstock."

With a more advanced pre-treatment, biohydrogen can even be produced from the waste from food-crop cultivation, such as corn stalks and husks. Tens of millions of tonnes of this waste is produced every year in the UK. Diverting it from landfill into biohydrogen production addresses both climate change and energy security....

- Genetics of White Horses Unraveled

ScienceDaily (July 20, 2008)

The white horse is an icon for dignity which has had a huge impact on human culture across the world. An international team led by researchers at Uppsala University has now identified the mutation causing this spectacular trait and show that white horses carry an identical mutation that can be traced back to a common ancestor that lived thousands of years ago.

The study is interesting for medical research since this mutation also enhance the risk for melanoma.

The great majority of white horses carry the dominant mutation Greying with age. A Grey horse is born coloured (black, brown or chestnut) but the greying process starts already during its first year and they are normally completely white by six to eight years of age but the skin remains pigmented. Thus, the process resembles greying in humans but the process is ultrafast in these horses. The research presented now demonstrates that all Grey horses carry exactly the same mutation which must have been inherited from a common ancestor that lived thousands of years ago.
"It is a fascinating thought that once upon a time a horse was born that turned grey and subsequently white and the people that observed it were so fascinated by its spectacular appearance that they used the horse for breeding so that the mutation could be transmitted from generation to generation," says Leif Andersson who led the study. Today about one horse in ten carries the mutation for Greying with age.

It is obvious that humans across the world have greatly valued these white horses as documented by the rich collection of stories and paintings featuring white horses. In the paper the white horse as an icon for dignity is illustrated by reproducing a painting from the late 17th century of the Swedish king Karl XI on his white horse Brilliant.

The Grey horse is also very interesting from a medical point of view since the mutation also predisposes for development of melanoma. About 75% of Grey horses older than 15 years of age have a benign form of melanoma that in some cases develops into a malignant melanoma. Thus, the study reported today has also given new insight in a molecular pathway that may lead to tumour development....

- New-generation Of Simpler Sensors For Detecting Disease-causing Microbes And Toxins

ScienceDaily (July 21, 2008)

Scientists in Singapore are reporting development of a complete, palm-sized sensor that can detect disease-causing microbes, toxins, and other biological threats instantly without the need for an external power source or a computer.

The long-awaited device, ideal for remote medical clinics, battlefields, and other sites, represents the next-generation of faster, simpler biosensors, according to a new study.

In the new study, Pavel Neuzil and Julien Reboud explain that the new device uses an existing method for detecting DNA, proteins or cells based on their interaction with light shown on the nanostructured surface when these materials come into contact with it. Most existing biosensors of this type require the use of an external power source, a complex and costly analyzer and rely on an external personal computer to report the results....

- Snow Flea Antifreeze Protein' Could Help Improve Organ Preservation

ScienceDaily (July 21, 2008)

Scientists in Illinois and Pennsylvania are reporting development of a way to make the antifreeze protein that enables billions of Canadian snow fleas to survive frigid winter temperatures. Their laboratory-produced first-of-a-kind proteins could have practical uses in extending the storage life of donor organs and tissues for human transplantation, according to new research.

In the study, Stephen B. H. Kent and colleagues point out that scientists have tried for years to decipher the molecular structure and produce from chemicals in a laboratory the so-called "snow flea antifreeze protein (sfAFP)." Those steps are critical for obtaining larger amounts of the protein, which exists naturally in only minute quantities in snow fleas. The larger synthetic quantities can be used for further research and potential medical and commercial uses, they say.
The researchers made synthetic sfAFP, and showed that it has the same activity as the natural protein. They also produced variants, including one form of sfAFP with a molecular architecture that is the reverse, or "mirror image," of natural sfAFP and different from any other protein found in living things on Earth....

- Mouse protein linked to human disease
Date: 21/07/2008
The study of dark-skinned mice has led to a surprising finding about a common protein involved in tumour suppression, report researchers at the Stanford University School of Medicine. The results may lead to new treatments for bone marrow failure in humans.The protein, called p53, has been dubbed the "guardian of the genome" for its ability to recognise DNA damage and halt the division of potentially cancerous cells. However, in a new twist, it appears that p53 also responds to disruptions in the cell's protein factories, leading to changes in skin colour and causing anaemia in mice.

"This may be just the tip of an iceberg," said Gregory Barsh, MD, PhD, professor of genetics and of pediatrics. "When we think of p53, we think in extremes: high levels cause cell death, low levels cause cancer. This research shows that even moderate changes can have very important consequences. It also suggests that the activation of p53 may be involved in more pathways than we previously anticipated."

Barsh is the senior author of the study, which will be published on-line in Nature Genetics on July 20. Kelly McGowan, MD, PhD, a dermatologist and postdoctoral scholar in Barsh's laboratory, is the first author.

The researchers studied mutations that darken the feet, tails and ears of normally light-skinned mice. Alterations in pigmentation are not only easy to identify, but also often involve a variety of biologically important pathways that control more than just hair or skin colour.

McGowan homed in on two skin-darkening mutations, which she found affected specific protein components of the cell's ribosomes. Ribosomes act as cellular protein factories, translating the instructions encoded by RNA molecules into new proteins to do the cell's work.

The discovery was interesting because mutations affecting one of the same ribosomal proteins in humans are associated with Diamond-Blackfan syndrome, a condition that causes a type of anaemia specific to red blood cells. When the scientists examined the dark-skinned mice more closely, they found that these mice exhibited similar abnormalities in red blood cell formation.

"Diamond-Blackfan itself is fairly rare," said McGowan, "but the bone marrow failure that sometimes occurs in these individuals happens quite often in many other disorders, including acute myelogenous leukemia and multiple myeloma."

People with bone marrow failure are unable to produce enough red blood cells, white blood cells and/or platelets. They are susceptible to uncontrolled bleeding, infection and fatigue. Understanding the disorder in mice may help scientists and physicians develop new treatment for other, similar conditions.

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