Physiological responses in a variable environment: relationships between metabolism, hsp and thermotolerance in an intertidal-subtidal species.
Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky-eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins) and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps) occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT). The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment.
State Key Laboratory of Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen, Fujian Province, People's Republic of China. dongyw@xmu.edu.cn
Yun-wei
YW
Dong
Shan-shan
SS
Yu
Qing-lin
QL
Wang
Shuang-lin
SL
Dong
D000222:Adaptation, Physiological; D000818:Animals; D004777:Environment; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D012044:Regression Analysis; D013045:Species Specificity; D047528:Stichopus / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D013696:Temperature; D014872:Water Movements
D006360:Heat-Shock Proteins