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Glutathione (GSH) is the most abundant non-protein thiol in eukaryotic cells and acts as reducing equivalent in many cellular processes. We investigated the role of glutathione in Dictyostelium development by disruption of [gamma]-glutamylcysteine synthetase (GCS), an essential enzyme in glutathione biosynthesis. GCS-null strain showed glutathione auxotrophy and could not grow in medium containing other thiol compounds. The developmental progress of GCS-null strain was determined by GSH concentration contained in preincubated media before development. GCS-null strain preincubated with 0.2 mM GSH was arrested at mound stage or formed bent stalk-like structure during development. GCS-null strain preincubated with more than 0.5 mM GSH formed fruiting body with spores, but spore viability was significantly reduced. In GCS-null strain precultured with 0.2 mM GSH, prestalk-specific gene expression was delayed, while prespore-specific gene and spore-specific gene expressions were not detected. In addition, GCS-null strain precultured with 0.2 mM GSH showed prestalk tendency and extended G1 phase of cell cycle. Since G1 phase cells at starvation differentiate into prestalk cells, developmental defect of GCS-null strain precultured with 0.2 mM GSH may result from altered cell cycle. These results suggest that glutathione itself is essential for growth and differentiation to prespore in Dictyostelium. Keywords: Glutathione; [gamma]-Glutamylcysteine synthetase; Cell fate; Dictyostelium discoideum

The high performance liquid chromatography (HPLC) with petroleum derivatization was applied to measure the dissolved and particulate concentrations of the biogenic thiols cysteine (Cys), arginine-cysteine (Arg-Cys), glutamine-cysteine (Gln-Cys), gamma-glutamate-cysteine (gamma-Glu-Cys) and glutathione (GSH) in the subartic Pacific Ocean in the 2003 summer. It was observed that the most plentiful particulate thiol was glutathione while the most profuse dissolved thiol was gamma-Glu-Cys with concentration as high as 15 nM.

A study measured reactive folic acid and glutathione in the water column of the north east Atlantic using cathodic stripping voltammetry. Analyses revealed that folic acid existed throughout the water columns while glutathione stayed only in the upper water column. Glutathione concentration was found to hover from less than one to 15 nmol/l while folic acid concentration ranged from 0.10 to 4.0 nmol/l. Also, folic acid and glutathione were found to be quite reactive in the oceanic water column.