British scientists said they have developed a way of pinpointing variations in a person?s genetic code using a chemical test on saliva, meaning quick, cheap DNA tests for risks of certain diseases may be around the corner. Researchers at Edinburgh University said their technique, based on chemical analysis, can deliver reliable results without the need for expensive enzymes used in conventional DNA testing. Researchers said the chemical method was able to detect genes linked to cystic fibrosis in laboratory experiments using synthetic DNA. The team planned to market a cystic fibrosis test very soon and then run further research to see if the same method could be used to decode entire human genomes.
Tests which identify tiny variations or omissions in DNA code are increasingly being developed and marketed as ways of determining whether or not a person is healthy, susceptible to disease, or has a disease or serious risks of developing one. Cystic fibrosis, a life-threatening inherited disease in which internal organs such as the lungs and digestive system become clogged with thick sticky mucus, is one of a small number of diseases caused by a single, identifiable faulty gene. Companies around the world are racing to develop ever faster and cheaper gene sequencing techniques to offer scientists and drug makers swifter routes mapping whole genomes.
Experts said the ?holy grail? for such firms is to be able to decode a person?s entire genetic sequence for $1,000. In their breakthrough, Edinburgh University researchers said their chemical method would offer a speedy, cost-efficient alternative to existing DNA analysis. ?The market for DNA testing is quickly expanding as it becomes more affordable. Our method could help reach the goal of complete genome analysis in a few hours for less than $1,000,? they said. The team plans to tie up with researchers and establish their first commercial operations within the next six months.
Solar carpet
Roll out the micro-carpet? a new solar-cell design based on a blanket of silicon rods could produce electricity at a fraction of the cost of conventional solar devices. The carpets have yet to be made into a working solar cell, but preliminary measurements of their ability to absorb light and generate current suggest they could become a cheap replacement for existing technology.
The idea behind photovoltaic solar cells is straightforward: when sunlight strikes a material, it dislodges electrons, which start to flow in one direction. The electrons leave behind empty, positively-charged ?holes? that move the other way, effectively creating a current. It?s a simple idea, but it isn?t cheap. The material of choice for cells is often thin silicon wafers, which are efficient at absorbing light but expensive to produce.
Now researchers at the California Institute of Technology in Pasadena have found an alternative that uses one hundredth of the material of current silicon technology. Using a well-established technique for assembling nanowires on a surface, the researchers grew a ?carpet? of micrometre-scale silicon rods lined up like hairs standing on end. They then embedded the rods in a transparent polymer. This configuration alone is not enough to absorb light efficiently. To solve this problem, the team sprinkled aluminium oxide particles into the transparent polymer. These particles scatter incoming light so that it bounces around inside the array, increasing the light?s chances of striking a silicon wire. As a result, up to 85% of usable incident sunlight can be absorbed effectively.
The researchers said the silicon carpet outperforms conventional wafers at absorbing infrared frequencies. According to them, the result flies in the face of the established dogma that the most highly absorbing surface is a roughly textured wafer. The next step for them will be to make a fully functional solar-cell device from their silicon array. If successful, their silicon-based technology has the advantage that it should be relatively easy to incorporate into current manufacturing processes.
Reverse aging
In a surprise result that can help in the understanding of both aging and cancer, researchers working with an engineered type of stem cell said they reversed the aging process in a rare genetic disease. The team at Children?s Hospital Boston and the Harvard Stem Cell Institute were working with a new type of cell called induced pluripotent stem cells or iPS cells, which closely resemble embryonic stem cells but are made from ordinary skin cells. In this case, they wanted to study a rare, inherited premature aging disorder called dyskeratosis congenita.
One of the benefits of stem cells and iPS cells is that researchers can make them from a person with a disease and study that disease in the lab. Harvard Stem Cell Institute?s researchers were making iPS cells from dyskeratosis congenita patients to do this. In a recent report, they said the process of making the iPS cells appeared to reverse one of the key symptoms of the disease in the cells. In this disease, the cells lose telomerase, an enzyme that helps maintain the telomeres. These are the little caps on the ends of the chromosomes that carry the DNA.
When telomeres unwind, a cell ages. This leads to disease and death. But in cancer, telomerase appears to help tumour cells become immortal and replicate out of control. Some experimental cancer drugs target telomerase. A gene called TERC helps restore the telomeres and the researchers said it may be that tumour cells make use of TERC to become immortal.
Source: Reuters & Wired