Enzyme Activities of Gill, Hepatopancreas, Mantle, and Adductor Muscle of the Oyster (Crassostrea virginica) after Changes in Diet and Salinity

Abstract

Ballantyne, I. S., and 8 . A. Berges. 1991. Enzyme activities of gill, hepatopancreas, mantle, and adductor muscle of the oyster (Crassostrea virginica) after changes in diet and salinity. Can. 1. Fish. Aquat. Sci. 48: 1 1 1 7- 1123.We examined the effects of exposure to low salinity (113 seawater) on the maximal activities of enzymes of lipid oxidation, amino acid and ketone body metabolism, gluconeogenesis, and glycolysis in gill, mantle, hepatopancreas, and adductor muscle of the oyster (Crassostsea virginica). No significant metabolic reorganization occurred after 4-6 wk in low salinity. The few significant differences which were found between enzyme activities of high-and low-salinity treatment groups were always due to lower activities in the low-salinity group. In particular, hexokinase, fructose bisphosphatase, and 3-hydroxyacyl CoA dehydrogenase declined in gill, hepatopancreas, and adductor muscle. Since high ionic strength depresses the activity of many enzymes, the reduced ionic strength in the cells of the low-salinity group may perturb metabolism by elevating rates of enzyme activity. As indicated by the present study, part of the response to low salinity by euryhaline molluscs may involve reducing the activity of certain enzymes to achieve a homeostasis of metabolic function.On a 6tudi6 les effets de la salinit6 reduite 6113 dfeau sake) sur 11activit6 maximale des enzymes de I'oxydation tipidique, du m6tabolisme des acides amines et des corps cetoniques, de la glucon6ogen2se et de la glycolyse dans les branchies, te manteau, I1h6pato-pancreas et le muscle adducteur de l'huitre (Csasssstrea virginica).Aucune reorganisation m6tabolique n16tait notable au bout de 4 a 6 sem en salinit6 r6duite. hes quelques differences significatives obsewees entre les groupes gard6s 2 salinit6 6lev6e et r6duite 6taient toujours dues a des activites enzymatiques moindres chez le groupe garde 3 satinit6 r6duite. Plus particuli&rement, on a not6 la baisse de 11activit6 de I'hexokinase, de la.fructose-biphosph9tase et de la 3-hydroxyacyl-CoA-d6shydrog6nase dans les branchies, 11h6patopancr6as et le muscle adducteur. Etant donn6 qu'h concentration ionique 6levke 11activit6 de nombreuses enzymes diminue, le fait que la concentration ionique soit rkduite dans les cellules des hui'tres gard6es salinitk r6duite peut perturber le m6tabolisme en stimulant 11activit6 enzyrnatique. Comme on I'a constat6 dans 116tude present& ici, en partie, la reaction des mollusques euryhalins 3 une baisse de salinit6 peut gtre une diminution de l"ctivit6 de certaines enzymes pour le rnaintien de I'hom6sstase de la fonction m6tabsl ique.

Interactive effects of salinity and elevated CO2 levels on juvenile eastern oysters,Crassostrea virginica

“…These results indicate that exposure to low salinity may be associated with metabolic rearrangements that result in the preferential burning of lipids. Decrease of lipid stores in oyster juveniles kept at low salinity is consistent with earlier findings that low osmolarity changes the preferred fuel and strongly stimulates oxidation rates of acyl carnitines (C8-C18 fatty acid derivatives) in isolated oyster mitochondria (Ballantyne and Moyes, 1987b) while inhibiting glycolytic enzymes such as hexokinase and fructose biphosphatase (Ballantyne and Berges, 1991). Lysine concentrations were elevated by 70-80% in tissues of juveniles maintained in low salinity, consistent with the proposed high input of acetyl-CoA from lipid breakdown that may reduce the need for acetyl-CoA supply from lysine degradation.…”

Age-dependent patterns of antioxidants in Arctica islandica from six regionally separate populations with different lifespans

“…Indeed, individual enzyme activities and tGSH range among, but not above, the highest values observed in mantle and foot tissues in other bivalves with shorter lifespan, such as Crassostrea virginica, Mya arenaria, Laternula elliptica, Adamussium colbecki, Mytilus edulis, Pecten jacobaeus and P. maximus (Ballantyne & Berges 1991, Viarengo et al 1991, 1995, Gamble et al 1995, Sukhotin et al 2002, Philipp et al 2005a,b, 2006. However, in the presence of the same amount of antioxidants, ROS production by A. islandica mitochondria may be lower, either because of its extremely low metabolic rate (Begum et al 2009), or because of more efficient mitochondrial electron transport in its mitochondria.…”

Metabolism of the Pacific oyster,Crassostrea gigas, is influenced by salinity and modulates survival to the Ostreid herpesvirus OsHV-1

“…The first step in glycolysis is the phosphorylation of glucose by hexokinase (HK). Activity of HK declines in the Eastern oysters, Crassostrea virginica , at low salinity to achieve homeostasis of metabolic function ( Ballantyne and Berges, 1991 ). Also, activity of HK is lower in oysters infected by OsHV-1 than in uninfected oysters ( Pernet et al, 2012 ; Tamayo et al, 2014 ).…”

“…Activity of CS correlates with respiration rate in marine invertebrates and can be used as indicator of physiological condition ( Dahlhoff et al, 2002 ). Although salinity ( Ballantyne and Berges, 1991 ) or infection by OsHV-1 ( Pernet et al, 2012 ; Tamayo et al, 2014 ) do not influence CS activity in oyster, the interaction of salinity and OsHV-1 on CS has never been investigated.…”