Pleistocene mollusc assemblage in the slightly raised atoll lagoon of Niau (Tuamotu,French Polynesia)

Surveys conducted at Niau, a slightly raised atoll in the Tuamotu Archipelago, revealed a brackish community with only a few extant species of fishes, crustaceans and molluscs in the residual semi-enclosed lagoon. Dredging of superficial sediments near the Niau lagoon resulted in a rich shell mollusc assemblage with 120 species, dating from the Pleistocene Last Interglacial Maximum (120,000 years BP). The assemblage contains 3 previously described new species, collected nowhere else since, and 12 species locally extinct but extant in the Indo-Pacific. Results are compared with previous studies on Pleistocene reefs of the Indo-Pacific.     

Type II phospholipase A2 recombinant overexpression enhances stimulated arachidonic acid release

The coding sequence of type II phospholipase A2 from human placenta was cloned in a bovine papilloma virus-derived eukaryotic expression vector under the control of the metallothionein promoter. Stably transfected C127 mouse fibroblast lines were obtained with this vector. These transfected cells overexpressed a functional 14 kDa phospholipase A2, which was bulky secreted. However, a significant phospholipase A2 activity was measured in cell homogenates. The involvement of this 14 kDa phospholipase A2 in mechanisms related to stimulated arachidonic acid release was investigated. We could parallel the overexpression of phospholipase A2 with an increase in phorbol ester and fluoroaluminate-stimulated arachidonic acid release. Pertussis toxin inhibited this stimulation. These results suggest that the 14 kDa type II phospholipase A2 might contribute to stimulation of arachidonic acid release, and therefore to eicosanoid production.