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Michiels M, Daleo G, López Mañanes A. Differential modulation after feeding in different salinities and response to abscisic acid (ABA) and extracellular Ca 2+ of aminopeptidase N (APN) activity in the hepatopancreas of the intertidal euryhaline crab Neohelice granulata. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Modulation of aminopeptidase N (APN) activity in the digestive tract by various factors would be important to adjust digestive and absorptive processes under different physiological and (or) environmental conditions. We studied the postprandial responses at different salinities and the effect of abscisic acid (ABA) and extracellular Ca2+ on APN activity in the hepatopancreas (the main site for nutrient digestion and absorption) of the model species Neohelice granulata (Dana, 1851). Enzyme activity was determined at different times (0, 24, 48, and 72 h) after feeding in crabs acclimated either to 35 psu (osmoconformation) or 10 psu (hyper-regulation). APN activity increased around 50% at 24 h after feeding at 35 psu, whereas no changes occurred at 10 psu. Enzyme activity was also assayed in the presence of ABA (1 × 10–4 mol·L–1) or extracellular Ca2+ (1 × 10–4 mol·L–1), showing increments of 60% and 56%, respectively. The results suggest a role of APN in postprandial adjustments and its modulation by different chemical messengers by direct effect on the hepatopancreas. Moreover, to our knowledge, this work is the first to show the effect of ABA on a digestive enzyme in the digestive tract of an animal.
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Affiliation(s)
- M.S. Michiels
- Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Argentina
| | - G.R. Daleo
- Instituto de Investigaciones Biológicas (IIB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Mar del Plata, Mar del, Plata, Argentina
| | - A.A. López Mañanes
- Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Argentina
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Méndez E, Caruso Neves C, López Mañanes A. Two sodium pumps in the hepatopancreas of the intertidal euryhaline crab Neohelice granulata: biochemical characteristics and differential modulation after feeding. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
No study has been done on the existence, biochemical characteristics, and modulation of K+-independent ouabain-insensitive Na+ ATPase activity (the second sodium pump) in the digestive tract of intertidal euryhaline crabs and moreover on the coexistence and modulation under distinct physiological and (or) environmental conditions of different sodium pumps. We determined the occurrence, characteristics, and responses at different times (0, 1, 24, 48, and 120 h) after feeding upon distinct salinities of Na+ ATPase activity and Na+/K+ ATPase in the hepatopancreas of Neohelice granulata (Dana, 1851), which is a model species. The stimulation by Na+ under total inhibition of Na+/K+ ATPase activity revealed the occurrence of Na+ ATPase activity that was totally inhibited by 2 mmol·L–1 furosemide, exhibits Michaelis–Menten kinetics for ATP (apparent Km = 0.52 ± 0.16 mmol·L–1), and highest activity at around pH 7.4. In crabs acclimated to 35 psu (osmoconforming conditions), Na+ ATPase activity was highly increased (about 15-fold) (532 ± 58 nmol Pi·mg protein−1·min−1) in the hepatopancreas 48 h after feeding. In 10 psu (hyper-regulating conditions), Na+ ATPase activity decreased in the hepatopancreas 24 h after feeding (7 ± 9 nmol Pi·mg protein−1·min−1) and recovered initial values after 48 h (24 ± 35 nmol Pi·mg protein−1·min−1). Unlike Na+ ATPase, Na+/K+ ATPase activity did not change after feeding at any salinity, suggesting the specific modulation of the second sodium pump and its role in postprandial adjustments in the hepatopancreas.
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Affiliation(s)
- E. Méndez
- Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) – Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Argentina
| | | | - A.A. López Mañanes
- Instituto de Investigaciones Marinas y Costeras (IIMyC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) – Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Argentina
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