Hemocyte parameters of the Pacific oyster Crassostrea gigas a year after the Hebei Spirit oil spill off the west coast of Korea

Abstract

In marine bivalves, hemocytes support various physiological functions, including immune defense, nutrient transport, shell repair, and homeostatic maintenance. Although the eVects of marine contaminants on the immunological functions of bivalves have been extensively investigated, the impacts of oil spills are not well understood. Therefore, we investigated hemocyte parameters in the PaciWc oyster Crassostrea gigas 13 months after the Hebei Spirit oil spill (December 2007) oV the west coast of Korea. The parameters studied included hemocyte concentration and mortality, relative proportion of hemocyte populations, and immunological functions such as phagocytosis and oxidative activity using Xow cytometry. These immune-related parameters in oysters damaged by the oil spill were also compared to control oysters that were collected from an area unaVected by the spill. The Xow cytometry study indicated that granulocyte population, phagocytic capacity, and reactive oxygen species production in oysters exposed to crude oil 13 months prior were depressed compared to the unexposed control oysters. Our data suggest that immunocompetence in oysters aVected by the oil spill had not fully recovered 1 year after the accident, although more detailed studies on the physiology and disease resistance should be performed.

Impact of Polycyclic Aromatic Hydrocarbon Accumulation on Oyster Health

“…S. glomerata, having been exposed to Pyr and Flu for 7 days, differentially expressed many unique pattern recognition receptor proteins (Ertl et al, 2016) involved in detecting and neutralizing pathogens, including peptidoglycan recognition proteins, C1q domain-containing proteins, toll-like receptors, c-type lectins, c-type mannose receptors/macrophase mannose receptors, galectin, gram-negative bacteria binding protein, scavenger receptor, 2 -5 -oligoadenylate synthase 1, and fibrinogen-related proteins. In the field, exposure to an oil spill off the coast of Korea was associated with a possible reduction (not statistically significant) in granulocyte population and phagocytic capacity in M. gigas (Donaghy et al, 2010), while chronically exposed M. gigas measured to have elevated PAH tissue concentrations expressed immunotoxicity in the form of hemocytes with impaired mitochondrial function and a 50% reduction in phagocytic function (Auffret et al, 2004).…”

“…Oysters are especially of interest, due to their contaminant load often far exceeding their bivalve congeners (O'Connor, 2002;Leon et al, 2013;Wang and Lu, 2017;Liu et al, 2019) while displaying measurable signs of contaminant-induced stress. PAH exposure has been linked with increased antioxidant activity (Sarkar et al, 2017), altered immune system activity (Donaghy et al, 2010;Croxton et al, 2012), mutagenicity (Sarker et al, 2018), and larval abnormalities (Vignier et al, 2015) in oysters, which provide a long list of sublethal biomarkers with which to study the effects of such contaminants. Since oysters are of interest for human consumption, there are concerns over health risks due to their accumulation of toxic compounds (Hong et al, 2016;Liu et al, 2019;Wang et al, 2020), while the demand for the food source has been stimulating the growing oyster aquaculture industry (Botta et al, 2020).…”

Virulence of Vibrio alginolyticus Accentuates Apoptosis and Immune Rigor in the Oyster Crassostrea hongkongensis

“…Its ability to survive in such extreme environments is dependent on an open yet sophisticated circulation system that executes innate immune functions and allows unique strategies for stress adaptation, making oysters suitable biomarkers for health assessment of marine ecosystems ( 20 , 21 ). As adept phagocytes, oyster hemocytes function in both cellular and humoral defenses, which provide a fundamental basis for oysters to cope with infectious agents ( 22 , 23 ). Through transduction of immune signals, these circulating hemocytes recognize self and non-self-parts, while undergoing agglutination, phagocytosis, and encapsulation processes.…”

Effect of Extreme Heatwaves on the Mortality and Cellular Immune Responses of Purplish Bifurcate Mussel Mytilisepta virgata (Wiegmann, 1837) (=Septifer virgatus) in Indoor Mesocosm Experiments

“…Marine bivalves are often used as sentinel species in coastal environmental monitoring, as changes in environmental quality are often well preserved in their cells and tissues (Donaghy et al, 2009a(Donaghy et al, , 2010Vazzana et al, 2016Vazzana et al, , 2020Parisi et al, 2017;Kim et al, 2020). The sensitivity of bivalves to environmental stressors is driven by the different structural and functional characteristics of their circulating hemocytes (Pipe and Coles, 1995;Auffret, 2005;Renault, 2015).…”

“…Hemocytes are the primary cellular mediators of the defense system in marine bivalves that recognize and destroy invasive foreign material by phagocytosis, encapsulation, and production of reactive oxygen species (ROS) (Cheng, 1981;Hine, 1999;Donaghy et al, 2015). Accordingly, numerous studies have determined hemocyte activities in clams, oysters, and mussels using flow cytometry or microscopy to understand the effects of stressors caused by environmental changes (Donaghy et al, 2010(Donaghy et al, , 2016Donaghy and Volety, 2011;Hong et al, 2016).…”