Experimental formulation of an anti fouling paint with tributyl tin oxide as toxic pigment

Results of the experimental formulation of an antifouling paint incorporating TBTO as toxic pigment are presented in this paper. Of the various resins tested, namely, phenolic, cashew nut shell liquid (CNSL), epoxy linseed oil with rosin and limed rosin, the paint composition with limed rosin gave the critical leaching rate of TBTO. Acid alkali test showed dissolution of matrix and visible migration of toxin to the surface. Accelerated corrosion tests had not recorded any signs of corrosion in panels painted with or without barrier coat. Raft exposure studies indicated that the new formulation could resist fouling accumulation on painted panels for 9 months.

Molecular studies on the effect of germanium oxide on sponges, corals and ascidians

The stress response, at the molecular level, of the soft corals Dendronephthya klunzingeri and Heteroxenia sp., hard corals Acropora hyacinthus and A. valenciennesi, an ascidian Symplegma sp. and sponges Latruncula cortica and Callyspongia crassa to germanium oxide (GeO sub(2)) was evaluated. Evaluation was carried out using bioindicators. such as the level of expression of each of the heat shock proteins (HSPs) and the silicatein enzyme in response to the compound. However, the expression was measured by SDS Polyacrylamide Gel Electrophoresis (SDS PAGE) and western blotting. The harmful concentration of GeO sub(2) that produced noticeable molecular changes in the studied samples during the first 6-24 hours was 6 μg/ml. The two studied soft corals as well as the ascidian responded to the harmful concentration of germanium oxide by expressing the heat-shock protein 90 (hsp90), while the two hard corals responded by expressing hsp70, C. crassa by decreasing the level of silicatein enzyme and sponge L. cortica produced no change by any of the used biomarkers, The soft coral Heteroxenia sp. was found to be sensitive to mechanical stress during the experiment and it was more sensitive to 6 μg/ml of GeO sub(2) than the other soft coral D. klunzingeri. The two studied hard corals were sensitive to mechanical stress during the experiment, but A. hyacinth us showed higher sensitivity than A. valenciennesi. However, these 2 corals displayed reverse response to GeO sub(2). Primitive evidences were found in the SDS PAGE to distinguish the tissue of the soft coral from that of the hard coral on the molecular level; the soft coral showed two prominent protein bands (45 and 50 kDa) while the two prominent protein bands for hard corals were 31 and 116 kDa.