Metaleptea vol:Special meeting issue (Antalya, June 21-25, 2009)
International congress of orthopterology edition:10 location:Antalya, Turkey date:21-25 June 2009
Locust phase polyphenism is an intriguing example of phenotypic plasticity. It is subject to profound studies by several research groups for decades. Bit by bit the mechanism is explored but it is still not quit well understood and surrounded with a veil of mystery. Recently it turned out that peptides could trigger responses similar to phase related changes and that a biogenic amine is playing an important role as well. Since phase changes occur at the organismal level we expect to see an impact of phase change on the hemolymph protein content as well. Two dimensional differential gel electrophoresis, 2D-DIGE, is an elegant way to visualize the protein content or the proteoom as it is called from a given tissue or blood sample. Thus far we succeeded in optimizing the protocols for the analysis of both hemolymph and tissue samples of the two phases of the desert locust, Schistocerca gregaria. This means that we are able to extract proteins in a quantitative and qualitative manner and produce reproducible gels. The bottleneck however remains the absence of genomic information of the species under study. Indeed, the successful identification of high numbers of protein spots, in Drosophila melanogaster for example, basically relies on the available genomic databases by means of peptide mass fingerprinting (PMF). Using PMF it is sufficient to make a tryptic digest of a protein and measurement of the generated fragments by means of mass spectrometry. Based on the peptide mass pattern it is possible to identify the parent protein. For the locust proteins an additional, time consuming, step is required: amino acid sequencing of the generated tryptic peptides. This can also be done on the mass spectrometric instruments but again the absence of genomic information hamper the sequencing of these peptides. Despite these drawbacks the first proteins are being identified.