The rate of 90Sr2t deposition in Galaxea fascicularis was linear with respect to Sr2+ concentration (0.01-20 mM) and refractory to DCMU (1 pM), a n inhibitor of photosynthesis. The deposition rate of "Sr2+ in polyps incubated under a light intensity of 200 pE.m-2.s-2 was not significantly different from that in polyps incubated in total darkness. The deposition rate of 45Ca2+ (1-20 mM), on the other hand, exhibited saturation kinetics. In addition, i t was DCMU sensitive and enhanced by light. Our results therefore support observations reported elsewhere that K, : is inversely correlated with growth rate in reef corals. However, Sr2+ and Ca2+ deposition in G. fascicularis does not appear to involve similar biochemical mechanisms.

Modern day hospital treatments aim at developing electrochemical biosensors for early diagnosis of diseases using unconventional human bio-fluids like sweat and saliva by monitoring the electron transfer reactions of target analytes. Such kinds of health care diagnostics primarily avoid the usage of human blood and urine samples. In this context, here we have investigated the electron transfer reaction of a well-known and commonly used redox probe namely, potassium ferro/ferri cyanide by employing artificially simulated bio-mimics of human sweat and saliva as unconventional electrolytes. Typically, electron transfer characteristics of the redox couple, [Fe(CN)6]3−/4− are investigated using electrochemical techniques like cyclic voltammetry and electrochemical impedance spectroscopy. Many different kinetic parameters are determined and compared with the conventional system. In addition, such electron transfer reactions have also been studied using a lyotropic liquid crystalline phase comprising of Triton X-100 and water in which the aqueous phase is replaced with either human sweat or saliva bio-mimics. From these studies, we find out the electron transfer reaction of [Fe(CN)6]3−/4− redox couple is completely diffusion controlled on both Au and Pt disc shaped electrodes in presence of sweat and saliva bio-mimic solutions. Moreover, the reaction is partially blocked by the presence of lyotropic liquid crystalline phase consisting of sweat and saliva bio-mimics indicating the predominant charge transfer controlled process for the redox probe. However, the rate constant values associated with the electron transfer reaction are drastically reduced in presence of liquid crystalline phase. These studies are essentially carried out to assess the effect of sweat and saliva on the electrochemistry of Fe2+/3+ redox couple.

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