Seasonal variation of enzyme activities in Laminaria hyperborea

Abstract

The patterns of seasonal variation of enzyme levels in the brown alga Laminaria hyperborea (Gunn.) Fosl. have been investigated for the following enzymes: Ribulosebisphosphate-carboxylase (EC 4.1.1.39), phosphoenolpyruvate-carboxykinase (EC 4.1.1.32), glyceraldehyde-3-phosphate-dehydrogenase (NADP dep., EC 1.2.1.12), malate-dehydrogenase (NAD dep., EC 1.1.1.37), L-aspartate-2-oxoglutarate aminotransferase (EC 2.6.1.1), and mannitol-l-phosphate-dehydrogenase (EC 1.1.1.17). The first four enzymes exhibit a circannual periodicity, characterized by a pronounced 'spring-maximum' of enzyme activity in April and May. As a consequence, the phylloid can maintain high metabolic rates from early spring on, although water temperature has then only slightly risen above the annual minimum. This findings is discussed in relationship to the growth- and developmental cycle of L. hyperborea and to the seasonal variation of photosynthesis and light-independent CO2-fixation. The seasonal pattern, outlined above, correlates well with the circannual fluctuations of the nitrogen content of the sea and with the variation of the internal nitrogen- and nitrate-content of the alga. This coincidence may indicate that nitrogen levels play an important role in the regulation of enzyme activities and, hence, the metabolic capacities of L. hyperborea.

Physiological controls on the distribution of the macroalga Spyridea hypnoides: patterns along a eutrophication gradient in Bermuda

“…This was probably due to either insufficient nitrogen to support protein synthesis (Bird et al 1982) or to the degradation of proteins as storage compounds (Cooke et al 1979, Lapointe & Duke 1984. The marked decline in protein content in the outer bay transplants also may have been partly due to a reduction in photosynthetic enzymes associated with the lower tissue nitrogen content (Kuppers & Weidner 1980).…”

“…For S. hypnoides, however, nitrogen stores were insufficient to meet the metabolic needs for growth and mainten.ance when ambient nitrate concentrations were chronically low. The reduced carbon fixation in nitrogen-deficient macroalgae may be due to the lower activity of proteinaceous photosynthetic enzymes when nitrogen is limiting (Kuppers & Weidner 1980, Lapointe & Duke 1984 or to the diversion of photosynthetic intermediates to support transient nitrogen assimilation (Williams & Herbert 1989).…”

Aspects of carbon metabolism in relation to autumnal blade abscission in the kelp Pleurophycus gardneri (Phaeophyceae, Laminariales

“…However, the amount of laminaran in the stipe of P, gardneri was comparable to the laminaran content in the stipes of L. hyperborea, L. digitata and L, saccharina (Haug & Jensen 1954). Maximum tissue density (% dry weight of fresh weight) was also related to laminaran content in many Laminaria species (Black 1947a, b, Haug & Jensen 1954, Chapman & Craigie 1978, Kuppers & Weidner 1980. Fluctuations in laminaran in P. gardnen, however, cannot account for the var~ation in dry weight.…”

Seasonal variation in heteroside concentrations of field‐collected Porphyra species (Rhodophyta) from different biogeographic regions

“…The brown alga Laminaria hyperborea from Helgoland, North Sea, Germany for example, also exhibits a circannual periodicity for a set of enzymes of primary metabolism (e.g. Rubisco), characterized by a marked maximum of activity in spring and summer (Ku$ ppers & Weidner, 1980). In Laminaria species, these seasonal changes in enzyme activity are typically related to carbohydrate metabolism, such as increasing mannitol and laminaran contents towards the summer (Davison & Reed, 1985), but also to increased nitrate in tissues in spring (Dring, 1992), and are coupled with ecological strategy of growth as ' season anticipators ' (Kain, 1989).…”