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IMMUNOLOCALIZATION OF NITRATE REDUCTASE IN THE MARINE DINOFLAGELLATE GONYAULAX POLYEDRA (PYRROPHYTA) 1
Author(s) -
Fritz Lawrence,
Stringher Claudia Gadni,
Colepicolo Pio
Publication year - 1996
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1996.00632.x
Subject(s) - biology , dinoflagellate , nitrate reductase , chloroplast , immunogold labelling , botany , polyclonal antibodies , photosynthesis , gymnodinium , algae , biochemistry , enzyme , ultrastructure , antibody , ecology , phytoplankton , nutrient , immunology , gene
A polyclonal antibody, raised against nitrate reductase (NR) purified from the photosynthetic dinoflagellate Gonyaulax polyedra Stein, was used as a probe in immunogold‐labeling experiments on thin sections prepared from cells harvested both during day and night phases. Previous experiments have shown that both NR activity and the amount of immunoreactive NR in cell extracts is greater when day‐phase cells are examined, and this property was exploited as an internal control for the cytochemical labeling. We observed that in day‐phase cells, chloroplasts contained approximately three times more gold particles than night‐phase cells (highly significant difference; P < 0.0001), whereas cytoplasmic labeling levels remained relatively level between day and night. We conclude from the diurnal difference in labeling that our antibody faithfully reflects the distribution of NR in Gonyaulax cells. Thus, as in to some other higher plants and green algae, Gonyaulax compartmentalizes active NR in its chloroplasts.