Figure 3 Changes of GSH in algae cells at different growth stages (a)
and (b). Two-dimensional correlation fluorescence spectra (c)
.Two-dimensional asynchronous correlation fluorescence spectra and (d)
As Figure 4,the three-dimensional fluorescence spectrum of GSH shows
that during the growth period of microalgae, GSH is mostly in the
initial synthesis stage, so only one regional peak (region A) appears in
the contour plot and the peak area is small, and the peak height of GSH
in the three-dimensional fluorescence stereogram is low; On day 21,
Microcystis aeruginosa starts to enter the logarithmic growth period,
and the GSH in the algal cell starts to synthesize and transport, and
only one regional peak (region A) appears in the contour plot. On day
50, the intracellular GSH content reached its maximum, and the peak area
was the largest at this time, with three regional peaks, the outermost
region A, the middle region B and the innermost region C. The
three-dimensional fluorescence map showed the highest peak height of GSH
at this time. GSH is being synthesized, GSH/GSSG interconversion,
ASA-GSH cycle and synthesis of phytochelating peptide (PC) to play its
antioxidant role; Figure d enters the decay phase, the intracellular GSH
begins to metabolize and degrade, only two regional peaks (region A and
region C) remain and begin to decrease, and the peak height of GSH shown
in the three-dimensional fluorescence stereogram begins to decrease
Until the algal cells were completely dead, GSH was degraded to
L-γ-glutamylcysteine (L-γ-Glu-L-Cys, γ-EC), γ-glutamyl cycle potential
substrate, γ-glycine cysteine and other free amino acids by the
catalytic action of carboxypeptidase (CPase) and γ-glutamyl
transpeptidase (γ-GTase). The distribution of GSH content at different
stages was clear, and there were no other interferences in the system.