養殖アマノリの疾病に関する研究-1-白クサレ様病罹病組織の窒素代謝について

概要

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Nitrogen metabolism in Porphyra tenera fronds infected with "shirogusare" (like a white wasting disease) was studied. The results obtained are as follows: 1) Infected tissue possessed altered nitrogen metabolism: the water-soluble nitrogen (principally non-protein nitrogen and ammonia) content increased, whereas the water-soluble protein content decreased. 2) The concentration of free amino acids was decreased in the infected tissues. Marked decrease was noted in glutamic acid, alanine and cystine. 3) Glutamic acid dehydrogenase (EC 1.4.1.2 L-Glutamate: NAD oxidoreductase) was present in Porphyra frond. The optimum pH was about 7.8 and the enzyme activity was found to be markedly reduced in the infected tissue. Excess amounts of ammonia found in the infected tissues could be explained on the basis of their having reduced activity of the enzymes such as glutamic acid dehydrogenase. 4) The acumulation of ammonia in the infected tissue apparently suppressed the oxygen uptake in the mitochondrial fraction. It appears likely that cellular metabolic activity of the infected tissue is reduced. 5) These results suggest that the disease process of "shirogusare" is accentuated further by the accumulation of excess amounts of ammonia produced in the tissue as a result of either increased catabolism of protein or reduced conversion of ammonia to amino acids, or both.
日本水産學會の論文