| While sometimes overlooked, peptidomics and peptide diversity is one of the most important areas of research today. This is because of the vital role that naturally created peptides play in cellular and systemic communication. Peptides have been shown to control and regulate many physiological processes, including feeding, sleep, development, and even cell death. Currently there is a lack of knowledge as to the peptide content of different but related species, as well as peptide distribution throughout nervous system within the same species. Additionally, due to integrative activity of bioactive peptides in physiological processes, there is also great potential for their use as biomarkers to indicate disease infection or progression. To begin filling in these gaps in knowledge, mass spectrometric (MS) methods have been developed for both peptidomic analysis and biomarker identification. Specifically, matrix-assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry has been used for a majority of this work due to its sensitivity, high mass measurement accuracy, and high resolution. A MALDI time-of-flight/time-of-flight instrument was also used for tissue-specific peptidomic profiling due to its sensitivity and high throughput nature. Furthermore, as the application of these methods produced a large set of data, bioinformatics methods were developed and used to process and analyze the results of MS analysis. The combination of mass spectrometry with bioinformatics has enabled rapid comparison of peptidomes of five brachyuran crabs and the determination of peptide distribution among the model nervous system and neurohemal organs of the crustacean C. borealis. Furthermore, this approach also allowed the discovery of a panel of classifying features (biomarkers) from prion infected hamsters useful in identifying infected animals. Overall, this research has developed improved methodologies and tools for peptidomic analysis and demonstrated their utility in neurochemical signaling and biomarker discovery in biological fluids. |
