Metabolic enzyme activities in swimming muscle of medusae: is the scaling of glycolytic activity related to oxygen availability?
Thuesen, E.V.; McCullough, K.D.; Childress, J.J. (2005). Metabolic enzyme activities in swimming muscle of medusae: is the scaling of glycolytic activity related to oxygen availability? J. Mar. Biol. Ass. U.K. 85(3): 603-611 In: Journal of the Marine Biological Association of the United Kingdom. Cambridge University Press/Marine Biological Association of the United Kingdom: Cambridge. ISSN 0025-3154; e-ISSN 1469-7769, more |  |
| Authors | | Top | - Thuesen, E.V., more
- McCullough, K.D.
- Childress, J.J.
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| Abstract | This study compared the scaling of the glycolytic enzyme lactate dehydrogenase (LDH) and the Krebs cycle enzyme citrate synthase (CS) in the swimming muscle and tentacle tissue of the mesopelagic coronate scyphomedusa Periphyllaperiphylla in two populations living under different oxygen minimum layer conditions. The LDH and CS activities in these tissues of two other coronate scyphomedusae (Paraphyllinaransoni and Periphyllopsisgalatheae) and the bathypelagic narcomedusa Aeginacitrea were also studied. The scaling of these two enzymes along with total protein was investigated in whole organism homogenates of the surface-living scyphomedusa Aurelialabiata. Mass-specific LDH activities in swimming muscle showed positive scaling in relation to body size in Periphyllaperiphylla collected off California and Hawaii. Mass-specific LDH activities in tentacle tissue increased with regards to increasing mass only in specimens of P.periphylla collected off California. The LDH values of the scaling coefficient, b, in swimming muscle and tentacle were significantly higher in P.periphylla collected in the low oxygen waters off California than from those collected off the Hawaiian Islands in a higher oxygen environment. The LDH showed a significant decrease with body size in Aeginacitrea swimming muscle and in Aurelialabiata whole animal homogenates. The largest species in this study, Periphyllopsisgalatheae, had LDH activities similar to the smallest specimens of Periphyllaperiphylla. The results of this study suggest that the scaling of glycolytic activity is related to oxygen availability for P.periphylla. In Aurelialabiata, which is only exposed to episodic hypoxia, and Aeginacitrea, scaling of glycolytic activity is not affected by oxygen availability. |
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