Abstract
Although the uptake of amino acids from dilute solution by marine invertebrates is a well documented phenomenon, its nutritional significance to these organisms remains controversial. The results of several lines of experimentation provide direct evidence that dissolved amino acids are supplemental sources of nutrition for starved Aurelia aurita scyphistomae, their importance being both as sources of reduced carbon and of nitrogen. Eight weeks of food deprivation at 20°C result in a 77.5% reduction in the number of polyps strobilating in response to temperature increase and exposure to iodide. This effect can be abolished by exposing starved polyps to environmental concentrations of glycine or alanine during the starvation period. Exposure of starved polyps to dissolved glucose during the 8-week period also overrides the diminution of the strobilation response. However, starved and starved/glucose-exposed polyps produce a higher percentage of abnormal ephyrae than do fed and starved/amino acid-exposed polyps, emphasizing the role of dissolved amino acids as nitrogen sources. Oxygen consumption and malate dehydrogenase activity decline during 2 weeks of food deprivation. Exposure of starved polyps to dissolved glycine produces increases in both parameters. There is no effect of 2 weeks of food deprivation on glycine uptake by polyps. However, starvation does produce an apparently enhanced rate of glycine catabolism, due in part to the increased production of CO₂ from the alpha carbon of the molecule. The predominance of glycine among amino acids dissolved in seawater, and its increased oxidation during starvation, may enhance its importance as a supplemental energy source for marine invertebrates. ...
Shick, John Malcolm (1974). Uptake and utilization of dissolved glycine by Aurelia aurita scyphistomae: temperature effects on the uptake process; nutritional role of dissolved amino acids. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -175991.