Shotgun proteomics reveals physiological response to ocean acidification in Crassostrea gigas

• Main Authors: Timmins-Schiffman, Emma, Coffey, William D, Hua, Wilber, Nunn, Brook L, Dickinson, Gary H, Roberts, Steven B
• Format: Other/Unknown Material
• Language: unknown
• Published: PeerJ 2014
• Subjects: Pacific; Crassostrea gigas; Ocean acidification
• Online Access: http://dx.doi.org/10.7287/peerj.preprints.388v1; https://peerj.com/preprints/388v1.pdf; https://peerj.com/preprints/388v1.xml; https://peerj.com/preprints/388v1.html

Background. Ocean acidification as a result of increased anthropogenic CO 2 emissions is occurring in marine and estuarine environments worldwide. The coastal ocean experiences additional daily and seasonal fluctuations in pH that can be lower than projected end of century open ocean pH reductions. Projected and current ocean acidification have wide-ranging effects on many aquatic organisms, however the exact mechanisms of the impacts of ocean acidification on many of these animals remains to be characterized. Methods. In order to assess the impact of ocean acidification on marine invertebrates, Pacific oysters ( Crassostrea gigas ) were exposed to one of four different p CO 2 levels for four weeks: 400 µatm (pH 8.0), 800 µatm (pH 7.7), 1000 µatm (pH 7.6), or 2800 µatm (pH 7.3). At the end of 4 weeks a variety of physiological parameters were measured to assess the impacts of ocean acidification: tissue glycogen content and fatty acid profile, shell micromechanical properties, and response to acute heat shock. To determine the effects of ocean acidification on the underlying molecular physiology of oysters and their stress response, some of the oysters from 400 µatm and 2800 µatm were exposed to an additional mechanical stress and shotgun proteomics were done on oysters from high and low p CO 2 and from with and without mechanical stress. Results. At the end of the four week exposure period, oysters in all four p CO 2 environments deposited new shell, but growth rate was not different among the treatments. However, micromechanical properties of the new shell were compromised by elevated p CO 2 . Elevated p CO 2 affected neither whole body fatty acid composition, nor glycogen content, nor mortality rate associated with acute heat shock. Shotgun proteomics revealed that several physiological pathways were significantly affected by ocean acidification, including antioxidant response, carbohydrate metabolism, and transcription and translation. Additionally, the proteomic response to a second stress differed with p ...