Ontogenetic variation in digestive proteinase activity of larvae and postlarvae of the pink shrimp Farfantepenaeus paulensis (Crustacea : Decapoda : Penaeidae)
D. Lemos et al., Ontogenetic variation in digestive proteinase activity of larvae and postlarvae of the pink shrimp Farfantepenaeus paulensis (Crustacea : Decapoda : Penaeidae), MARINE BIOL, 135(4), 1999, pp. 653-662
Proteinase (endopeptidase), trypsin-like and chymotrypsin-like activities w
ere examined throughout the ontogenetic development of cultured Far fantepe
naeus paulensis. Whole individuals from different larval and postlarval sta
ges, and the hepatopancreas of adults were homogenized and assayed to quant
ify the enzyme activities of specific substrates. Proteinase activity was i
dentified by substrate-SDS-polyacrylamide gel electrophoresis. Specific inh
ibitors for trypsin (TLCK), chymotrypsin (TPCK) and serine proteinases (PMS
F) were used to identify activity zones of these enzymes in gels. Protein-s
pecific activity of total proteinases, trypsin and chymotrypsin was negligi
ble at the egg stage and at Nauplius III, increasing in the first protozoea
l substage (PZ I), and reaching a peak at PZ III; it decreased again in the
subsequent postlarval substages. Different patterns of proteinase activity
were observed in SDS-PAGE zymograms during ontogenetic development. Active
bands of 14.6, 16.4, 17.5, 19.5, 22.5, 23.9, 25.8, 28.9, 32.0, 34.4, 37.7,
and 42.2 kdaltons were detected in the adult hepatopancreas, Proteolytic a
ctivity was detected on gels in PZ I, and intense activity zones of 16.4, 1
7.5 and 19.5 kdaltons were found up to Mysis I(M I). Intense bands of 39.1
and 53.5 kdaltons were observed only at PZ III and M I. Band-activity inten
sity decreased after metamorphosis to the postlarval stage (PL). The chymot
rypsin inhibitor TPCK had no effect on the proteinase bands. Active zones i
n gel inhibited with both TLCK and PMSF were considered to represent trypsi
n. The inhibitory effect of PMSF alone on proteinase extracts indicated chy
motrypsin activity. TLCK and PMSF inhibition also varied during ontogenetic
development. The inhibition of bands recorded between 14.6 and 21.7 kdalto
ns suggested the presence of low molecular weight trypsin in F. paulensis.
The 39.1:kdaltons band observed at PZ III and M I were trypsin-like. On the
other hand, bands of 28.9, 32 and 37.7 kdaltons from the adult hepatopancr
eas seem to represent a chymotrypsin. We conclude that the recorded variati
on in enzyme activity may be associated with morphological and behavioral c
hanges during penaeid ontogenetic development. The higher enzyme activity a
t PZ II, PZ III and M I may reflect the increased energy turnover associate
d with intense swimming behavior and food ingestion.