Role of water-soluble matrix fraction, extracted from the nacre of Pinctada maxima, in the regulation of cell activity in abalone mantle cell culture(Haliotis tuberculata)

In mollusks, the mantle is responsible for the secretion of an organic matr ix that mineralizes to form the shell. A model of mantle cell culture has b een established from the nacreous gastropod Haliotis tubercullata. First, v iability of cells, quantified by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide) reduction assay, was monitored in order to de termine a cell density and a time-culturing period in order to investigate biomineralization precesses in vitro. During the first 11 days of culture, an increase of MTT response demonstrated an activation of cultured cells mi tochondrial activity as confirmed by the total protein content assay. The e ffect of a water-soluble extract from the organic matrix of Pinctada maxima (WSM) was tested on this cell culture system for II days-period exposure. WSM reduced the global viability of mantle cells in a dose-dependent way wh ich corresponded to a cell death. Alkaline phosphatase activity normalized to total protein content increased in the presence of WSM. This increase ma y be due to an activation of cells and a selection of one (or a few) cell t ype(s). Further investigations will help us to determine this selectivity i ssue. (C) 2001 Harcourt Publishers Ltd.