Monday, 24 February 2014

Synthetic Biology bring out the old....

Synthetic Biology has set the world of Biotech alight. According to one definition, "Synthetic biology is the design and construction of biological devices and systems for useful purpose". So what is it? Well it is partly the application of Molecular Cloning technology, pioneered by a small number of Bacterial Geneticists and Biochemistrst in the early 1970s and turned into a commercial enterprise by companies including New England Biolabs in particular in the 1980s. It is also in part the application of engineering principles to the construction of molecular components (devices) and whole cells (or Biological entities) using this technology. In a sense it is a "mature" form of Molecular Biology, in that it is supposedly based on concrete knowledge, rather than emerging knowledge. So how robust is the knowledge base? This is precisely what we are going to investigate this term in the Y12 project.

Molecular cloning in E.coli, has been a standard technique in most Molecular Biology labs since about 1985. In essence, the ingredients are a duplex of DNA encoding the gene of interest, a cloning vector (which can be a bacterial plasmid [shown under a microscope, right] or bacteriophage) a competent host strain and a means of selecting the uptake of the recombinant plasmid, created by joining, or "ligating" the DNA fragment with the cloning vector. Several important enzymes including restriction enzymes and DNA ligase (some of which are now replaced by recombinantion enzymes) are also needed. The cells then do their work by converting a few copies of the recombinant plasmid into many millions of copies.

This amplification of the DNA fragment was revolutionised further by the invention of PCR: the Polymerase Chain Reaction, in which a thermostable (heat resistant) DNA Polymerase is used in a number (around 20-30) cycles to amplify a DNA template (as described in the recent Master Class from the LGC scientist). So two strands become 4, 4 become 8 until amplification of a million fold occurs (see left). So to obtain a few micrograms of DNA, all that is needed for cloning, we only need a few femtograms of template DNA. This is why PCR is so good in forensic science work.

What are we going to attempt. One of our partners, Croda, have asked if would look at the possibility of cloning the genes that encose enzymes that synthesise short proteins, in fact so short that we called them peptides. These enzymes are found in certain strains of cyanobacteria and we are going to try and use PCR to amplify them, followed by capturing the genes in plasmid vectors and providing Croda with strains to test for their ability to produce peptides. If we get our experimental design correct, we should be able to make short peptides to order. This would be of considerable interest to teh Personal Care Sector.

No comments:

Post a Comment