Abstract: The primary objective of this study was to conduct an initial analysis of the proteome of exhaled breath condensate or blow in aquarium-based bottlenose dolphins (Tursiops truncatus) and, secondarily, to determine the commonality of proteins identified in blow with those in plasma of the same animals as recently documented. Exhaled breath condensate was collected from four young (2 to 6 y old), male dolphins using a 50-mL Falcon tube held above the blowhole for ten sequential exhalations; total volume ranged from 60 to 122 μL. Subsequent to analysis of total protein, 20 μg of protein from each dolphin was separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Of the four samples, three produced sufficient resolution of 15 bands that were excised from respective gels and subject to liquid chromatography-tandem mass spectrom¬etry (LC-MS/MS) and used for protein identification. Mass spectra data were used to search the National Center for Biotechnology Information (NCBI) database restricted to all mammalian proteins. Based on proteins having ≥ 2 peptides and present in at least two of the three dolphins, a total of 220 blow proteins were identified. While a majority (38 to 51%) of proteins could not be categorized, gene ontology indicated protein binding (26%), cytoplasm constituents (16%), and immune response (16%) dominated the molecular function, cellular component location, and biological process domains, respectively. From noncontemporaneous samples, NCBI Accession numbers of 220 blow proteins described herein and 196 plasma proteins previously identified by LC-MS/MS in the same dolphins were matched. Results indicated a commonality of 21 proteins (5%), with ten (48%) related to the immune system (e.g., complement- and immunoglobulin-related pro-teins) and the remainder to other various biological systems. Although preliminary, the novelty of these results provides additional support that exhaled breath condensate can be a relevant, less invasive alternative to blood collection to assess or monitor physiological health and pathological states. More specifically, the commonality of several immune-related proteins between the circulatory and respiratory systems provides a foundation for future investigations to determine the potential of these blow proteins as biomarkers that may be diagnostic or prognostic of respiratory health in bottlenose dolphins and, perhaps, other cetaceans.
Key Words: blow, proteomics, exhaled breath condensate, cetacean, bottlenose dolphins, Tursiops truncatus
Document: Article
DOI: https://doi.org/10.1578/AM.44.3.2018.256
Page Numbers: 256-266

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