Seawater Acidification Reduced the Resistance of Crassostrea gigas to Vibrio splendidus Challenge: An Energy Metabolism Perspective

Abstract

Negative physiological impacts induced by exposure to acidified seawater might sensitize marine organisms to future environmental stressors, such as disease outbreak. The goal of this study was to evaluate if ocean acidification (OA) could reduce the resistance capability of the Pacific oyster (Crassostrea gigas) to Vibrio splendidus challenge from an energy metabolism perspective. In this study, the Pacific oyster was exposed to OA (pH 7.6) for 28 days and then challenged by V. splendidus for another 72 h. Antioxidative responses, lipid peroxidation, metabolic (energy sensors, aerobic metabolism, and anaerobic metabolism) gene expression, glycolytic enzyme activity, and the content of energy reserves (glycogen and protein) were investigated to evaluate the environmental risk of pathogen infection under the condition of OA. Our results demonstrated that following the exposure to seawater acidification, oysters exhibited an energy modulation with slight inhibition of aerobic energy metabolism, stimulation of anaerobic metabolism, and increased glycolytic enzyme activity. However, the energy modulation ability and antioxidative regulation of oysters exposed to seawater acidification may be overwhelmed by a subsequent pathogen challenge, resulting in increased oxidative damage, decreased aerobic metabolism, stimulated anaerobic metabolism, and decreased energy reserves. Overall, although anaerobic metabolism was initiated to partially compensate for inhibited aerobic energy metabolism, increased oxidative damage combined with depleted energy reserves suggested that oysters were in an unsustainable bioenergetic state and were thereby incapable of supporting long-term population viability under conditions of seawater acidification and a pathogen challenge from V. splendidus.

Contrasting Immunomodulatory Effects of Probiotic and Pathogenic Bacteria on Eastern Oyster, Crassostrea Virginica, Larvae

“…Upregulation of cox3, hspa12a, and hspa12b is a key indicator of high metabolic demand and oxidative stress [ 70 ], and the lack of expression of genes coding for antioxidant enzymes suggests that larvae are unable to effectively handle the oxidative stress and high metabolic demand due to the inability to rapidly clear RE22 infection. This is consistent with the well-documented effect of bacterial infection on the transcriptomes of susceptible bivalve hosts [ 53 , 67 , 71 , 72 , 73 ].…”

The extensive intergenerational molecular effects of ocean acidification on the olfactory epithelium transcriptome of a marine fish are associated with a better viral resistance

“…macromolecules biosynthesis). At a general level, we also detected higher expression of genes related to the AMPK signalling pathway, consistent with related work in the brain of sh exposed to OA a well as in other marine species (Schunter et al 2018;Cao et al 2018). Extending from these ndings, and unexpectedly, we also discovered that D. labrax, upon intergenerational exposure to OA, up-regulated gene programs conferring elevated resistance to virus infection.…”

Impact of Ocean Acidification on the Energy Metabolism and Antioxidant Responses of the Yesso Scallop (Patinopecten yessoensis)

“…Recent studies have shown that modest increases in dissolved CO 2 (<1200 μatm) have little effect on metabolic rates, whereas extremely high levels of dissolved CO 2 (>5000 μatm) could depress metabolic rates (Michaelidis et al, 2005; Beniash et al, 2010; Hendriks et al, 2010; Thomsen and Melzner, 2010; Zhao et al, 2017b). As shown by Cao et al (2018), Pacific oyster ( Crassostrea gigas ) modulates energy sources by inhibiting aerobic energy metabolism, stimulating anaerobic metabolism, and increasing glycolytic enzyme activity following exposure to a reduced pH value of 7.6 for 28 days. The clams (Ruditapes philippinarum ) were reported to be able to maintain/regulate their physiological status and biochemical performance under reduced pH (7.3) for 28 days (Velez et al, 2016).…”