Directed evolution is a process wherein a gene sequence is
varied randomly, generating a library of mutated genes. These mutated genes are
expressed and the functions of those gene products are assayed. A selection
procedure is then applied to select those genes that express products with
desirable functions. These genes are then selectively amplified and the
mutagenesis, screening and selection process is repeated until gene products
with the most desirable functions are obtained.
The screening process involves exciting genes with light and
observing the fluorescence from these genes or from molecules they are
associated with. This screening process, being visual, is slow, unautomated and
incompatible with high throughput screening. This greatly limits the number of
cells that can be selected. It is almost always the case that directed evolution
procedures select for changes in either the amount of or the chemical properties
of the gene, but never both. Thus the capability of performing directed
evolution using a fluorescent assay that was both amenable to automation and
would distinguish between fluorescence amplitude and fluorescence lifetime is a
significant asset not only for research but for diagnostics and therapeutics as
well.
Neal Woodbury at Arizona State University has invented a
method using fluorescence and optical techniques for screening large numbers of
individual cells or colonies of cells that yield fluorescence lifetime data.
Analysis of this data is controlled and performed in an automated and rapid
manner. This screening method can then be used in cell selection procedures in
conjunction with additional methodologies based on their fluorescent properties,
which were also developed by the research group. Using these new methods, one
can kill cells in a uniquely selective manner, thus promoting the selective
survival of the remaining cells.
Potential Applications
- Biotechnology research and development
Benefits and Advantages
- Automated process
- Rapid screening of a large number of colonies
- Highly selective
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For more information about the inventor(s) and their
research, please see
Dr.
Woodbury's departmental webpage
Dr.
Woodbury's directory webpage
