The sea squirts Ciona intestinalis and C. savignyi have disparate distribution patterns, which may result from differences in their thermal tolerance limits. Because C. intestinalis, an almost cosmopolitan species, has a more widespread distribution, it is thought that it is better adapted to endure a wide range of temperatures. In order to compare the heat stress response between these two congeners, we studied global changes in protein expression, using a proteomics approach. To characterize the response to extreme heat stress, animals of both species were exposed to temperatures of 22°C, 25°C, and 28°C for 6 h, and then were left to recover at a control temperature (13°C) for 16 h. An additional experiment was conducted to assess the effect of mild-to-moderate heat stress including a 6 h exposure to temperatures of 18°C, 20°C, and 23°C, and a 16 h recovery at a control temperature (16°C). A quantitative analysis, using 2D gel electrophoresis and gel-image analysis, showed that in the high heat stress (HHS) experiment, 15% and 18% of the all protein spots detected demonstrated changes in expression in C. intestinalis and C. savignyi, respectively. In the low heat stress (LHS) experiment, 4% of the total number of proteins detected changed significantly in both C. intestinalis and C. savignyi. Using matrix-assisted laser desorption ionization (MALDI) tandem time-of-flight mass spectrometry, we were able to identify proteins with a 65-100% success rate, depending on species. Our results indicate that C. intestinalis maintains higher baseline levels of molecular chaperones and launches a quicker response to thermal stress than C. savignyi, suggesting it may be the more thermally tolerant of the two. In addition, actins, tubulins, and ATP-synthase F1 β-subunits were the most susceptible to proteolytic degradation, which may indicate that they have relatively higher thermal sensitivities.
Identifer | oai:union.ndltd.org:CALPOLY/oai:digitalcommons.calpoly.edu:theses-1467 |
Date | 01 January 2011 |
Creators | Serafini, Loredana |
Publisher | DigitalCommons@CalPoly |
Source Sets | California Polytechnic State University |
Detected Language | English |
Type | text |
Format | application/pdf |
Source | Master's Theses |
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