Digestive flexibility in response to environmental salinity and temperature in the nonsymbiotic sea anemone Bunodosoma zamponii

DEL VALLE, J. C; ACUÑA, F. H.; LÓPEZ MAÑANES, A. A.

HYDROBIOLOGIA

SPRINGER

Lugar: Dordrecht; Año: 2015 vol. 759 p. 189 - 199

0018-8158

The knowledge about digestive physiology of sea anemones at biochemical level is scarce, particularly in South American species. The final digestion of various dietary glycogenic carbohydrates depends on suitable levels of disaccharidases (ie: maltase). In spite of their important physiological role for maintaining glucose homeostasis, to our knowledge, no studies occur about the occurrence of maltase activity in coelenteron of sea anemones. The objective was to determine the existence and biochemical characteristics of maltase activity in coelerenton mesenterial filaments of the South American sea anemone Bunodosoma zamponii.  Sea anemones (n=10) captured in the intertidal zone of Punta Cantera (Mar del Plata, Buenos Aires, Argentina) were maintained at 35 psu, 12 h L/12 h O and 20°C The supernatant (10000xg) from homogenate mesenteric filaments was used. Maltase activity was assayed by hydrolysis of 28.0 mM of maltose in 0.1 M maleate/NaOH buffer (pH 6.4) at 37°C. To study the effect of pH, maltose concentration, and temperature the activity was deter­mined at different: pH levels (5.9-8.4), substrate concentra­tions (0.56-42 mM) and temperature (4-37°C) of the reaction mixture, respectively.  Maltase activity was high over the wide range of pH and temperature tested and exhibited Michaelis-Menten kinetics (Km 0.31± 0.4 mM). Our results show the occurrence of maltase activity in mesenterial filaments of B. zamponii suggesting  its capacity for digestion and potential use of various glycogenic substrates as nutrient sources. The high activity over a wide range of pH and temperature suggests that this capacity would be maintained under varying physiological and/or environmental conditions.