Tuesday, April 1, 2008

What do you get if you cross brewer’s yeast with a jellyfish and a rat?

Genetically modified organisms aren’t only crops and food but include glowing pets, spider-goats capable of producing spider silk and pigs with spinach genes but what do you get if you cross brewing yeast with a jellyfish with a rat? The answer is a cheap explosive detector and regretfully, not a new party drink that changes colour when cheese is mixed into it.

At the Temple University in Philadelphia, Pennsylvania a molecular biologist called Danny Dhanasekaran has succeeded in creating yeast, with a rat’s sense of smell that are capable of identifying the main ingredient in many explosives, trinitriluene or more commonly known as TNT. Once the yeast has detected TNT it produces a glow by employing its jellyfish abilities.

It is Dhanasekaran’s hope to invent a portable detector much cheaper then the already existing bomb detectors that employ electronic olfactory sensors. With his funding from the Defence Advanced Research Projects Agency in the Pentagon it may not be long before we see these yeast sensors in shopping centres, railway stations or built into a mobile phone sized device carried by policemen.

A rat’s olfactory senses work by allowing different odour molecules to fasten onto a specific protein which sends an electrical signal to the brain. Rats have a very accurate sense of smell as their olfactory senses contain about 500 proteins. The reason brewer’s yeast, Saccharyces cerevisiae was selected as the communications channel was because it uses the same type of protein receptors as rats, to detect pheromones for reproduction.

To alert it’s user that they are in the presence of TNT, a jellyfish gene which encodes a green fluorescent protein only visible under ultraviolet light was inserted, resulting in this jellyfish protein being activated when the specific olfactory pathway for TNT is activated.

Using this practice Dhanasekaran hopes to construct identifiers for other chemical and biological weapons. If Dhanasekaran succeeds in properly engineering the yeast, they will live up to 15 days and exist in a semi-solid film built into magazines which fit into mobile phone sized detectors.


Bibliography

Source One:
Pickrell, J 2006, ‘Instant Expert: GM Organisms’, viewed 24 March 2008, <http://www.newscientist.com/channel/life/gm-food/dn9921>

Source Two: Diesel, E, ‘Mutation Paste Gets Results!’, viewed 25 March 2008, <http://cedros.globat.com/~thebrites.org/News/MutationPasteResults.html>

Source Three:
Marks, P 2007, ‘Genetically modified yeast can sniff out explosives’, viewed 24 March 2008, <http://www.newscientist.com/channel/life/gm-food/mg19426036.000-genetically-modified-yeast--can-sniff-out-explosives.html>

Posted By: Jeffrey Hanson
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Myopia and our genes


In recent years, people started to be concerned more about their health. Nearsightedness (myopia) is a disease occurres around the world; it is an essential issue because it influences quality of life significantly. According to the American Academy of Family Physicians, Myopia is the most common eye problem. It affects as much as 40 per cent of the population in the US and Europe but between 70 and 90 per cent of some Asian populations.

Myopia is the medical term for nearsightedness. People with myopia see objects more clearly when they are close to the eye, while distant objects appear blurred or fuzzy. Reading and close-up work may be clear, but distance vision is blurry.

In a long time, it is believed that myopia is caused by lifestyle. Some bad habits like reading the book too closely, reading in caliginous light, having a lot of alcoholic drink, watching screen (including TV, computer, PSP, NDSL, etc) too long... are believed to contribute to the formation of myopia.

However, according to the recent research at St. Thomas' Hospital in London, PAX6, the gene that is found on chromosome 11, is linked to myopia, and it is a fundamental gene to eye development. Since it’s such an important gene, most mutations in this gene cause major eye abnormalities. That explains why some children are born susceptible to being near-sighted; their eyes are more sensitive to the environment.

Furthermore, a variety of genetic patterns for inheriting myopia have been suggested, ranging from a recessive pattern with complete penetrance in people who are homozygotic for myopia to an autosomal dominant pattern; an autosomal recessive pattern; and various mixtures of these patterns. One explanation for this lack of agreement is that the genetic profile of high myopia (defined as a refractive error greater than -6) may differ from the low myopia. Some researchers think that high myopia may be determined by genetic factors to a greater extent than low myopia.

While the genetic factors that influence the transmission and severity of myopia may not be changed easily, some environmental factors can be modified. They include reducing close work; reading and working in good light; taking frequent breaks, maintaining good nutrition, and having more outdoor activities.

Hope you all have great eyesight.
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