Characterization of mussel gill cells in vivo and in vitro

Abstract

Mussel gill cells are attractive models in ecotoxicological studies because gills are the first uptake site for many toxicants in the aquatic environment; gill cells are thus often affected by exposure to pollutants. Our aim was to characterize mussel gill cells in vivo and in vitro by using morphological, histochemical and functional end-points. In paraffin sections stained with haematoxylin-eosin, three zones were distinguished in the long central gill filaments: frontal, intermediate and abfrontal. Various types of ciliated cells were present in the frontal zone, and both ciliated and non-ciliated cells were found in the abfrontal zone. The intermediate zone was comprised of flattened endothelial cells. Lipofuscin granules occurred in the three zones in variable amounts, depending on the specimen. Haemocytes were found in the haemolymph sinus of gill filaments. Mucocytes were identified in both frontal and abfrontal zones by means of periodic acid Schiff-alcian blue (PAS-AB) staining. In cryostat sections, succinate dehydrogenase (SDH) activity was mainly found in ciliated cells, whereas neutral lipids and acid-phosphatase-reactive lysosomes were present in all portions of the gill filament, mostly being related to lipofuscin granules. In mussels exposed to 5'-bromo-2'-deoxyuridine in vivo, proliferating cells were scattered throughout the gill filament. Gill cells (typically 2x10(7) cells/ml per mussel; 95% viability) were isolated by dissociation with dispase. Gill cell suspensions were heterogeneous: 58% were ciliated epithelial cells (positive for SDH), 42% were non-ciliated cells (including epithelial cells and haemocytes), 2.3% were mucocytes (positive for PAS-AB) and 4.25% were haemocytes (able to phagocytose neutral red-stained zymosan). Gill cell cultures were maintained up to 18 days without changing the culture medium, viability decreasing below 50% at day 18. Primary cultures of mussel gill cells might therefore be useful models for the in vitro assessment of xenobiotic impacts on coastal and estuarine ecosystems.

Comparison of taurine related compounds in deep- and shallow-water mussel species

“…Therefore, high levels of hypotaurine and thiotaurine seem to be a common characteristic of the gills of bathymodiolin mussels. High levels of hypotaurine in the gill are to be expected, considering its function is to detoxify sulfides, because the gill is the first organ that is in contact with ambient water (Gómez-Mendikute et al 2005). High levels of hypotaurine and thiotaurine throughout the genus is consistent with the possibility that shifts in habitat and symbiont types have occurred several times within the genus (Jones et al 2006, Lorion et al 2010.…”

Development of an in vitro culture method for cells and tissues from the zebra mussel (Dreissena polymorpha)

“…This may be due to its high amino acid content, an important component of the mollusc diet (Renault et al 1995). Recommendations on how often media should be changed vary from every 2 days (Takeuchi et al 1994), 4 days (Kleinschuster et al 1996), 3 weeks (Brewster and Nicholson 1979), to not at all (Gomez-Mendikute et al 2005). It was found that for the zebra mussel a media change every 4-6 days was suitable.…”

“…However, some success has been reported in mantle explants from bivalves with the detection of DNA synthesis after 13 days in culture (Koyama and Aizawa 2000), mitotic figures from 7-day-old cultures (Cornet 2006), and functional viability after 40 days (Barik et al 2004). Gill cells were also maintained in suspension for up to 18 days with 50% viability (Gomez-Mendikute et al 2005). Numerous published reports of cell reproduction were suspected of having been contaminated by thraustochytrid species (common marine and freshwater heterotrophic protists; Rinkevich 1999) and as far as the authors are aware despite being able to maintain living cells in culture for aquatic invertebrates, the ability to encourage cell reproduction and the growth of differentiated tissue in vitro has still not yet been achieved.…”

“…Isolated cells from various bivalve mollusc species have been used in toxicological studies including digestive gland and blood cells Le Penec 2001, 2003;Chelomin et al 2005;Parolini et al 2009), heart cells (DomartCoulon et al 2000), mantle (Cornet 2006) and gills (Gomez-Mendikute et al 2005). The usefulness of bivalve molluscs as bioindicators of environmental change has long been established due to their high filtration rate, ability to accumulate and bioconcentrate toxicants, widespread distribution and abundance and their primarily stationary, benthic lifecycle.…”

Isolation and fractionation of gill cells from freshwater (Lasmigona costata) and seawater (Mesodesma mactroides) bivalves for use in toxicological studies with copper

“…Studies examined the gill tissue and analysed the cells of freshwater mussels, Pyganodon cataracta, Utterbackia imbecillis and Ligumia substrata (Unionid mussels), and reported different cellular types, including the 'cells rich in mitochondria', which play a significant role in active uptake of ions and solute transport into and out of the gills (Kays et al 1990;Schwartz and Dimock, 2001). In vivo and in vitro gill epithelium analyses were also performed in the seawater mussel Mytilus galloprovincialis (Gómez-Mendikute et al 2005). Findings reported the presence of ciliated (58 %) and nonciliated (42 %) cells, including epithelial cells and haemocytes (4.3 %).…”