Annual variations in arginine metabolism and phenolic content of Evernia prunastri
Evernia prunastri thalli showed seasonal variations in soluble amino acids and arginine-degrading enzymes. The concentration of storage polyols, ribitol/arabitol and mannitol had a sharp peak during August–September, but their amounts were stable throughout the rest of the year. Ribitol and arabitol contents were ten times higher than that of mannitol. Arginine comprises the major portion of the nitrogen reserved during early summer. The concentration of this amino acid decreased through the autumn, winter and spring months. Glycine, serine and alanine were, together with arginine, some of the more abundant thalloid amino acids in this lichen species. Arginase activity was relatively low during winter and showed high activities during June–August. Arginine decarboxylase and agmatine amidinohydrolase had high values during early autumn (late September). The urea content of E. prunastri could be related to arginase activity; i.e. when arginase activity was highest (in June) the urea content was also highest. RNA content and RNase activity were maximal during the winter. The changes in the activities of arginase, arginine decarboxylase, agmatine amidinohydrolase and urease may be related to seasonal variation in lichen phenolics. The hydrolytic pathway of arginine catabolism occurs during the spring and summer months, when the concentration of evernic acid in the thallus is low. The alternative route of decarboxylation proceeds when the hydrolytic pathway does not, and occurs when there are low concentrations of atranorin, chloroatranorin and usnic acid and the highest concentration of evernic acid in the thallus.
| Main Authors: | , , , , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Language: | English |
| Published: |
Elsevier
1986
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| Online Access: | http://hdl.handle.net/10261/241033 http://dx.doi.org/10.13039/501100007272 |
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