Digestive flexibility in Neohelice granulata from the Mar Chiquita coastal lagoon: Characterization and modulation of key enzymes in hepatopancreas

Abstract

The study of different physiological aspects of the digestive tract (i.e.,components involved at the biochemical level and mechanisms ofmodulation) is extremely relevant for the integrated knowledge of thefunctioning of living organisms. Digestive enzymes play an essentialphysiological role as a link between ingestion, absorption, and assimilationof nutrients. In many animals, modulation of digestive enzyme activitiescan lead to digestive adjustments for facing diverse variations in keyenvironmental conditions (del Valle et al. 2006, Karasov and Douglas2013). In the digestive tract of several vertebrate and invertebrate species,membrane transport systems (such as sodium pumps), as well asmembrane enzymes such as alkaline phosphatase (AP), accomplish a keyrole in the maintenance and/or adjustment of digestive, absorptive andsecretion processes. The hepatopancreas of decapod crustaceans is main site of digestive enzymes synthesis, digestion, absorption, andstorage of nutrients (Carter and Mente 2014, Saborowski 2015, Ribeiro etal. 2016). However, integrative studies on the occurrence and modulationof key enzymes in the hepatopancreas of euryhaline intertidal crabs, arescarce and fragmentary.In Mar Chiquita coastal lagoon (Argentina), the crab Neohelicegranulata successfully occupies the entire intertidal area, from openmudflat to vegetated saltmarsh, being exposed to varying conditions inseveral environmental factors (Spivak et al. 1994, Fanjul et al. 2008, Luppiet al. 2013). Therefore, it is expected to exhibit digestive flexibility to facethese heterogeneous habitats. In this chapter, we describe the currentknowledge about characteristics and modulation of key enzymes involvedin both digestion and absorption processes, in the hepatopancreas of adultmales from the mudflat of Mar Chiquita coastal lagoon (Buenos AiresProvince Argentina, 37°32-37°45S; 57°19-57°26W). Furthermore, acomparison was drawn with the digestive enzyme activities in thehepatopancreas of crabs from the saltmarsh.