Rhogocytes (pore cells) as the site of hemocyanin biosynthesis in the marine gastropod Haliotis tuberculata

Abstract

Rhogocytes (pore cells) are specific molluscan cell types that are scattered throughout the connective tissues of diverse body parts. We have identified rhogocytes in large numbers in tissue taken from mantle, foot and midgut gland of the abalone Haliotis tuberculata (Vetigastropoda). Within cisternae of the endoplasmic reticulum, particles are visible that resemble, in shape and size, hemocyanin molecules, the respiratory protein of many molluscs. Immunohistochemical experiments using hemocyanin-specific antibodies demonstrated that these cells contain hemocyanin. In situ hybridization with a cDNA probe specific for Haliotis hemocyanin showed that hemocyanin-specific mRNA is present in rhogocytes, which confirmed that they are the site of hemocyanin biosynthesis in this gastropod. A possible path of hemocyanin release into the hemolymph is discussed. Also in the vetigastropod Megathura crenulata, many rhogocytes could be detected. However, they lacked hemocyanin molecules which, together with published data, indicates a seasonal expression of hemocyanin in this animal.

Red blood with blue-blood ancestry: Intriguing structure of a snail hemoglobin

“…Moreover, the higher-order quaternary structure of both proteins is achieved by using the subunit dimer as the repeating unit. Remarkably, gastropods synthesize both proteins in the same cell type, the so-called pore cells or rhogocytes, from which they are released by merocrine secretion (30,31). It therefore appears that the planorbid snails use the same cellular machinery as their gastropod relatives to express red blood as an alternative to the phylogenetically older blue blood.…”

Ultrastructure of the renopericardial complex in Hypselodoris tricolor (Gastropoda, Nudibranchia)

“…Possible functions of the rhogocytes include a major role in the metabolism of metal ions and the detoxification of heavy metal ions (see review by Haszprunar 1996). Furthermore, it has been shown recently by means of electron microscopy and immunohistochemical experiments (Albrecht et al 2001) that rhogocytes represent the site of haemocyanin biosynthesis in Haliotis tuberculata Linné, 1758 (Vetigastropoda). However, in the present investigation we were unable to identify haemocyanin molecules in the vacuoles of the rhogocytes.…”

Concholepas hemocyanin biosynthesis takes place in the hepatopancreas, with hemocytes being involved in its metabolism

“…In contrast, this function resides in the hepatopancreas of the tetrabranchiate Nautilus pompilius (Ruth et al 1996). On the other hand, roghocytes, which are also known as pore cells, have been shown to synthesize hemocyanin in several pulmonate gastropods molluscs, such as Lymnaea stagnali (Sminia and Boer 1973), Helix aspersa (Sminia and Vlugh-van Dallen 1977), and Haliotis tuberculata (Albrecht et al 2001). In addition, roghocytes are involved in hemocyanin homeostasis in Sepia officinalis (Beuerlein et al 2002a).…”

“…The biosynthesis of hemocyanins in molluscs has been studied previously (Ruth et al 1988(Ruth et al , 2000van Holde and Miller 1995;Taylor and Anstiss 1999;Albrecht et al 2001;Streit et al 2005). Several experimental studies involving immunohistochemical and cytochemical techniques with anti-hemocyanin antibodies together with in situ hybridization assays using RNA probes have demonstrated that hemocyanin biosynthesis in molluscs occurs in various organs depending on the species studied.…”