Rainbow in a pot
New advances in synthetic biology
From October 31 to November 2, the Massachusetts Institute of Technology hosted the next annual international student competition on synthetic biology projects International Genetically Engineered Machine Jamboree (iGEM).
To participate in this competition, student teams from all over the world, by combining DNA fragments – "parts of a biological designer", create microorganisms programmed to perform useful functions, for example, the production of drugs or the detection of toxins. Every year, the "details" used to create the microorganisms participating in the competition are placed in a biological library available to participants of subsequent competitions. According to Tom Knight, one of the iGEM organizers, the main idea is to create an extensive library of such details to create complex genetic constructs suitable for embedding in living bacterial cells.
In past years, yeast producing beer with the beneficial properties of red wine, producing a pleasant aroma of Esherihia coli (how these bacteria, often used as an experimental organism, smell without genetic engineering, it is not difficult to guess from their Russian name "E. coli"); and various probiotic bacteria fighting tooth decay and lactose intolerance, as well as vitamins capable of synthesizing.
Among this year's finalists were "GluColi" – bacteria synthesizing a new generation of glue – and a biological analogue of a liquid crystal display consisting of yeast. However, the greatest resonance was caused by bacteria that can change their color depending on the concentration of the toxin contained in the medium. This development received not only the main prize of the competition, but also the first place in the nomination "Best environmental project".
Representatives of the winning team from Cambridge University arrived at the competition with a suitcase full of colorful poop (which, however, were intended only for demonstration purposes and made of wax). The contents of the suitcase, or "Scatalog", as the creators themselves called it (obviously with a hint of the word "scatology"), are six large artificial samples of a chair, each of which is speckled with one of the colors: purple, blue, green, yellow, orange and pink.
The owners of the suitcase – young designers helping the Cambridge team of biologists – explained that the Scatalog is a visual demonstration of the potential of a diagnostic method based on the use of genetically modified E. coli, capable of changing color depending on the amount of toxin contained in the medium or the desired compound.
Currently, the invention of young researchers is a modified E.coli, which in the presence of arsenic changes color to one of the above. To create their brainchild, named "Esherihia chromi", the young researchers analyzed the iGEM database containing information on more than 3,000 biological details. To obtain yellow and orange colors, they chose the genes of carotenoid enzymes of the bacterium Pantoea ananatis, which causes onion rot. The melanin gene from the genome of the soil bacterium Rhizobium etli provided a brown color, and the gene complex of Chromobacterium violacein living in water and soil provided shades of purple, green and blue.
The idea of using such bacteria is very simple. A person will only need to swallow a couple of capsules with a bacterial preparation and after a while, without leaving home, get the result of his analysis. Theoretically, in such an uncomplicated way, it is possible to detect not only toxins, but also markers of various diseases of the digestive tract, including cancer. The development of such test systems requires solving a number of complex problems, including protecting chameleon bacteria from the body's immune system, as well as obtaining approval from the US Food and Drug Administration (FDA) for their use, but experts believe that in general this is quite realistic.
During iGEM, the Cambridge team held about 20 informal presentations of the Scatalog, each of which began with a burst of laughter and ended with a serious discussion on the practical use of the achievements of synthetic biology.
Evgenia Ryabtseva, Alexander Chubenko
Portal "Eternal youth" http://vechnayamolodost.ru based on iGEM 2009 materials
14.12.2009