Zinc speciation promotes distinct effects on dinoflagellate growth and coral trypsin-like enzyme activity.

Zinc is an essential metal to living organisms, including corals and their symbiotic microalgae (Symbiodiniaceae). Both Zn(II) deprivation and overload are capable of leading to dysfunctional metabolism, coral bleaching, and even organism death. The present work investigated the effects of chemically defined Zn species (free Zn, ZnO nanoparticles, and the complexes Zn-histidinate and Zn-EDTA) over the growth of the dinoflagellates Symbiodinium microadriaticum, Breviolum minutum, and Effrenium voratum, and on the trypsin-like proteolytic activity of the hydrocoral Millepora alcicornis.

Thermodynamic Description of Oxotransfer Processes Involving Molybdenum and Tungsten Enzyme Models: DFT Calculations and Calorimetry.

The enthalpy of the oxotransfer reaction of [BuN][WO(mnt)] (where mnt is maleonitriledithiolate) with PPh in an inert atmosphere in an acetonitrile solution was determined by calorimetry. The obtained enthalpy value (-93 ± 5) kJ mol differs from the enthalpy value of the reaction carried out by us earlier under aerobic conditions by (16 ± 9) kJ mol. The obtained results indicate the participation of atmospheric oxygen in the catalytic process.