The Effect of Brefeldin a on the Golgi Apparatus in Norway Spruce Cells

Abstract

The effect of the fungal antibiotic Brefeldin A (BFA), was studied in two different cell systems of Norway spruce (Picea abies): embryogenic tissue cultures and root meristems. We analyzed the Golgi apparatus (GA) ultrastructurally with TEM in tissues after exposure to 50, 100 and 200 µg/mL of BFA for 1 and 3 hr. Striking morphological modifications of the GA occurred in both cell systems. Often the GAs were seen to have: reduced number of cisternae; curled cisternae, which also became very electrondense, narrow and elongated; abnormal-looking cisternae closely positioned between two ER strands; and cisternae fragmentation. These abnormalities were more pronounced in cells treated with the higher concentrations of BFA, and in the tissue culture system. Such cells, after treatment with 200 µg/mL BFA, had almost completely distorted GAs, and many clusters with a large number of vesicles present. After a recovery period of 1 hr, the observed effects of BFA were reversed. When comparing the extent of changes of the GA in the two tissue systems, we conclude that the cultured cells are more sensitive to BFA. Other organelles seemed not to be affected by BFA.