PROTEOLYTIC ACTIVITY IN HEPATOPANCREAS OF THE EURYHALINE CRAB Neohelice granulata: RESPONSE TO HYPEREGULATION AND FEEDING

MÉNDEZ, E; LÓPEZ MAÑANES, A; PINONI, S

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza; Año: 2012 vol. 3 p. 61 - 61

0327-9545

Hyperegulation is a physiological status with enhanced energy demands. Biochemical adjustments in extrabranchial organs (i.e. modulation of digestive enzymes in hepatopancreas) could occur in response to hyperegulation and could be affected by feeding status. However, integrative studies on these adjustments are lacking. The aim of this work was to determine proteolytic activity (Prot) at different times after feeding in hepatopancreas of N. granulata from Mar Chiquita coastal lagoon acclimated to different salinities (S) (35‰S:osmoconformation; 10‰S:hyperegulation). Adult male crabs exposed for 10 days to 35 and 10‰S (feeding regime: 3 times a week), were unfed for 5 days (preingesta=PI) and then individually fed. Prot was determined in PI, immediately (t0) and at 1, 8, 24, 48, 72, 120 h post-ingesta. Prot (enzyme units×h-1×mg protein- 1) was assayed by measuring azocasein (1%p/v) hydrolysis in Tris-HCl, 100 mM, pH 7.5. PI and t0 values were similar both in 35 and 10‰S. In 35 ‰S, Prot was higher between 8 (8.23 ± 0.2) and 72 h (8.9±1) post-ingesta than in PI (5.04 ± 0.95). In 10‰S, no differences occur between PI (4.2±0.87) and any time post-ingesta. No differences were found between osmoconformation and hyperegulation conditions in either PI or at any time post-ingesta (p=0.001). The results shows a different Prot responses to feeding in 35 and 10‰S suggesting a relationship between post-feeding adjustments and osmoregulatory status.