Relationship of branchial architecture and ultrastructure of ion-transporter cells in the physiological mechanisms that allowed the invasion of diluted medium by Anomura (Crustacea, Decapoda): Aegla franca (Schimitt) and Clibanarius vittatus (Bosc)

Author(s)

Cláudia Doi Antunes

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2011-04-11

Examining board members

John Campbell McNamara; Rosa dos Prazeres Melo Furriel Jorge; Claudia Bueno dos Reis Martinez

• Advisor: John Campbell McNamara

Abstract

Crustaceans exhibit different patterns of osmotic regulation and are the gills that absorb ions from the external environment more diluted. The gill cells that carry out ion transport present apical evaginations and basal membrane invaginations associated with mitochondria, which provide ATP to Na+/K+-ATPase inserted in the basal infoldings. The Na+/K+-ATPase is critical in extracellular anisosmotic regulation. We aim to generate knowledge for the discussion of functional adaptive strategies that allowed the occupation of dilute medium by Anomura, from information about the gill type and ion-transporting cells ultrastructure in Aegla franca (Aeglidae), strong-hyperregulator and Clibanarius vittatus (Diogenidae), weak-hyperregulator. The animals were acclimated in the laboratory and ion-transporters tissues located by silver staining technique. Gills were dissected, fixed and evaluated at the optical microscopy, scanning electron and transmission. A. franca presents trichobranchia, and there are functional differences between the artrobranchias and pleurobranchias. The architecture of the gill filament is given by a simple epithelium, below the cuticle, formed by pillar cells on the lateral sides. The septum divides the hemolymph space in the afferent and efferent channels and forms lateral gaps. The presence of apical evaginations and basal invaginations associated with mitochondria suggests the occurrence of ion transport. After acclimatization for 10 days in seawater at 25‰S, no reduction of these sub cellular structures happened, which suggests secretion of Cl-, since this specie hyporregulates chloride in this salinity. C. vittatus presents phyllobranchia and apparently the artrobranchias have greater relevance in osmoregulation. The architecture is given by a simple epithelium under the cuticle, formed by pillar cells and its flanges, there is an intralamelar septum. The cellular structures are few, rarely are mitochondria and infoldings are very scarce. The subcuticular space is small and there are desmossomes between adjacent flanges. The perikaryum region is rich in basal invaginations and mitochondria. After acclimatization for 10 days in seawater at 15‰S had the emergence of numerous membrane invaginations and increase of mitochondria number in the septum. In pillar cells showed an increase in apical evaginations and desmossomes appeared followed by a septate junction intercaled. These changes are related to salt active transport in dilute medium, as they allow host ion-transport enzymes, and apparently this is what allows the penetration and retention of C. vittatus in the low salinity medium. (AU)