Transcriptional expression levels of cell stress marker genes in the Pacific oyster Crassostrea gigas exposed to acute thermal stress

Abstract

During the annual cycle, oysters are exposed to seasonal slow changes in temperature, but during emersion at low tide on sunny summer days, their internal temperature may rise rapidly, resulting in acute heat stress. We experimentally exposed oysters to a 1-h acute thermal stress and investigated the transcriptional expression level of some genes involved in cell stress defence mechanisms, including chaperone proteins (heat shock proteins Hsp70, Hsp72 and Hsp90 (HSP)), regulation of oxidative stress (Cu-Zn superoxide dismutase, metallothionein (MT)), cell detoxification (glutathione S-transferase sigma, cytochrome P450 and multidrug resistance (MDR1)) and regulation of the cell cycle (p53). Gene mRNA levels were quantified by reverse transcription-quantitative polymerase chain reaction and expressed as their ratio to actin mRNA, used as a reference. Of the nine genes studied, HSP, MT and MDR1 mRNA levels increased in response to thermal stress. We compared the responses of oysters exposed to acute heat shock in summer and winter and observed differences in terms of magnitude and kinetics. A larger increase was observed in September, with recovery within 48 h, whereas in March, the increase was smaller and lasted more than 2 days. The results were also compared with data obtained from the natural environment. Though the functional molecule is the protein and information at the mRNA level only has limitations, the potential use of mRNAs coding for cell stress defence proteins as early sensitive biomarkers is discussed.

Comparative physiological, biochemical, and molecular thermal stress response profiles for two Unionid freshwater mussel species

“…Most studies comparing HSP90 responses primarily focus on within-species population comparisons (Farcy et al, 2009;Fangue et al, 2006) rather than between-species comparisons. Overall values are presented on the left: the ANCOVA were further separated into the heat shock period (middle), when the ponds showed a temperature differential, and the recovery period (right), when the ponds showed no difference in temperature at the end of the experiment.…”

Anticipatory gene regulation driven by maternal effects in an insect–host system

“…Values correspond to levels of mRNA of each studied gene standardized to GADPH , as normalizing gene (see Farcy et al. 2009, and Methods, for details).…”

Actin gene from blood cockle Anadara granosa as a potential housekeeping gene for gene expression analysis

“…This environment presents a challenge to organisms as they must cope with fluctuating water condition and antropogenic impact. Changing environmental conditions, such as temperature, salinity, mercury concentration, parasite, and ultraviolet (UV) radiation, stimulates stress on bivalve and other organism (Farcy et al, 2009;Kravets et al, 2012).…”

“…Actin gene has been used as a housekeeping gene to normalize gene expression in human (Goidin et al, 2001), sheep (Garcia-Crespo et al, 2005, mice (Ikegami et al, 2002), and bivalve Crassostrea gigas (Farcy et al, 2009). It encompasses constant expression levels and needs no induction factor to be expressed.…”