Physiological and Transcriptional Responses to Acute and Chronic Thermal Stress in the Ark Shell Scapharca subcrenata

Abstract

Ark shells (Scapharca subcrenata) grown on the tidal flats are often exposed to high temperature stresses in summer. In order to better understand their adaption to extreme or natural high temperature, we first determined the 96-h upper lethal temperature of ark shell and then investigated their physiological and transcriptional responses to acute or chronic thermal stress at the 96-h upper median lethal temperature (32°C). A significantly higher cumulative mortality (52% in 96 h) was observed in the acute heating treatment (AHT) group than that (22% in 7 days) in the chronic heating treatment (CHT) group. The apoptosis and necrosis rates of hemocytes were increased significantly in a time-dependent manner under both thermal stress strategies. Activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] increased dramatically in a short time followed by a quick decline and reached to a lower level within 12 h in the AHT group, but maintain relatively high levels over a long period in the CHT group. The contents of malondialdehyde (MDA) were increased significantly firstly and restored to the original later in both acute and chronic thermal stress. Moreover, expression of the genes related to heat shock proteins (HSPs; HSP90, HSP70, HSP20, and sHSP), apoptosis [TNF receptor-associated factor 6 (TRAF6), glucose regulated protein 78 kD (GRP78), and caspase-3 (Casp-3)] and antioxidant responses [glutathione S-transferase (GST) and multidrug resistance protein (MRP)] could be induced and up-regulated significantly by thermal stress, however, expression of regucalcin (RGN), metallothionein (MT), and peroxiredoxin (PRX) was down-regulated dramatically under the two heating treatments. These results suggested that anti-apoptotic system, antioxidant defense system and HSPs could play important roles in thermal tolerance of ark shells, and the heat-resistant ark shell strains could be selected continuously by properly chronic thermal stress.

Molecular Cloning and Functional Characterization of Catalase in Stress Physiology, Innate Immunity, Testicular Development, Metamorphosis, and Cryopreserved Sperm of Pacific Abalone

“…In the present study, induced CAT activity and higher Hdh-CAT mRNA expression levels were observed in response to thermal stress. Similar findings have been previously reported for CAT in scallop [4], ark shell [21], Mediterranean mussel [60], and Pacific oyster [61]. The present study also found elevated ROS levels in thermal-stressed abalone, consistent with previous findings of American oyster [31].…”

“…Temperature is a vital abiotic factor that can significantly affect the physiology of marine organisms [21]. In recent decades, seawater temperature has been rising with the acceleration of climate change [21,56].…”

“…Temperature is a vital abiotic factor that can significantly affect the physiology of marine organisms [21]. In recent decades, seawater temperature has been rising with the acceleration of climate change [21,56]. Temperature changes are known to influence ROS production and activate antioxidant enzymes in mollusk [57].…”

“…Whereas heat stress induces H 2 O 2 production [16,17] that ultimately increases CAT expression [18][19][20]. Heat stress also induces CAT activity and increases its mRNA expression in a marine mollusk, Scapharca subcrenata [21]. Cold stress imbalances CAT activity and expression in scallop, Chlamys nobilis [4].…”

Seasonal energetic physiology in the ark shell Anadara kagoshimensis in response to rising temperature

“…Our results suggest that the warming of the sea is reflected in the physiological performance and ultimately the seasonal cycle in flesh weight of the ark shell in different manners between winter and summer: physiological benefits and advanced weight gain vs. heat stress and progressive weight loss (Ning et al, 2021;Zou et al, 2021), respectively. Our measurements revealed the absence of seasonal temperature acclimation in the physiological processes of A. kagoshimensis.…”