Immunocytochemical localization of ribulose 1,5-bisphosphate carboxylase/oxygenase in light-limited and light-saturated cells of Chlorella pyrenoidosa
Chlorella pyrenoidosa, Immunocytochemistry, Pyrenoid, Ribulose 1, 5-bisphosphate carboxylase/oxygenase
The localization of ribulose 1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) in cells of C. pyrenoidosa grown at varying light intensities was determined by immunoelectron microscopy. Log phase cells grown at photon flux densities of 25 and 75 μEm-2s-1 (light-limiting) and 540 μEm-2s-1 (light-saturating) were fixed in 3% glutaraldehyde and embedded in Lowicryl K4M. Sections were labelled with antiserum to each subunit of RuBisCO followed by protein A-gold. At each light fluence rate, the pyrenoid was heavily labelled by each antibody whereas chloroplast stromal labelling was not above background levels. The apparent absence of stromal RuBisCO at each light level, and hence the lack of enzyme redistribution from pyrenoid to stroma following an increase in light fluence rate, suggests that pyrenoid RuBisCO is functional in vivo. © 1989 Springer-Verlag.
McKay, R. M.L. and Gibbs, Sarah P.. (1989). Immunocytochemical localization of ribulose 1,5-bisphosphate carboxylase/oxygenase in light-limited and light-saturated cells of Chlorella pyrenoidosa. Protoplasma, 149 (1), 31-37.