Cadmium toxicity on the freshwater microalga Chlamydomonas moewusii Gerloff: Biosynthesis of thiol compounds.

Cadmium (Cd) toxicity and production of different thiols (phytochelatins, glutathione, gamma-Glu-Cys and cysteine) were studied in the microalga Chlamydomonas moewusii exposed to different concentrations of this metal (1, 2, 4, 6, 8, and 10 mg/L) for 96 h. The inhibitory effect of Cd on growth was demonstrated. The value of EC50 (metal concentration which reduces the population growth to 50% of the control) obtained for this microalga was estimated at 4.

Structure and metal loading of a soluble periplasm cuproprotein.

A copper-trafficking pathway was found to enable Cu(2+) occupancy of a soluble periplasm protein, CucA, even when competing Zn(2+) is abundant in the periplasm. Here, we solved the structure of CucA (a new cupin) and found that binding of Cu(2+), but not Zn(2+), quenches the fluorescence of Trp(165), which is adjacent to the metal site. Using this fluorescence probe, we established that CucA becomes partly occupied by Zn(2+) following exposure to equimolar Zn(2+) and Cu(2+).

Sorption isotherm studies of Cd(II) ions using living cells of the marine microalga Tetraselmis suecica (Kylin) Butch.

The present work reports the use of living cells of the marine microalga Tetraselmis suecica for the biosorption of cadmium ions. For a better understanding of the biosorption characteristics, three fractions of removed cadmium (total, bioadsorbed and intracellular) were measured in the cells after 24 and 72 h of exposure to different initial cadmium concentrations (0.6-45 mg L(-1)).

A capillary zone electrophoresis for determination of thiolic peptides in biological samples.

A new method to improve the analyses of thiolic peptides (cysteine, gammaGlu-Cys, glutathione, phytochelatins and desglycyl-phytochelatins) derivatized with monobromobimane (mBrB) in complex biological samples by CZE is described. The method involves a SPE using Sep-Pak Light C18 Cartridges after derivatization and a later CZE analysis. Elution of mBrB-thiols was achieved with 10 mM HCl + 70% methanol v/v in deionised water.

Dunaliella salina as marine microalga highly tolerant to but a poor remover of cadmium.

Cadmium tolerance and removal in the marine microalga Dunaliella salina were studied in cultures exposed to different metal concentrations (5-120 mg Cd l(-1)) for 96h. This microalga can be included in the group of microalgal species most tolerant to cadmium due to the high value of EC50 that it possesses (48.9 mg Cd l(-1) at 96 h of culture).