ABSTRACT
To evaluate the effects of brefeldin A (BFA) on
Golgi bodies and indirectly on the polarized development of S. cymosum zygotes, zygotes were
cultured at concentrations of 4 μM, 8 μM, 16 μM and 32 μM of BFA, prepared in
sterilized seawater. After 12 hours, the samples were fixed and processed for
transmission electron microscopy (TEM), confocal laser scanning microscopy,
light microscopy and cell counting. For
recovery analysis, after treatment, the samples were
again placed in sterile seawater for over 12 hours. In the control, after 12 hours,
the embryos were adhered and with advanced stage of development, presenting up to
6 cell divisions. In the treated samples, the embryos did not adhere and only
in the lower concentrations were they visualized with cellular divisions, is that in the highest concentration, the majority of the
zygotes were dead. After recovery, embryos showed development only in the
lowest concentrations. By confocal microscopy, the treated samples had an
irregular distribution of chloroplasts and physodes. Also through TEM, it was
possible to observe the loss of organization of Golgi bodies, in turn leading
to the formation of vesicles and fusion of physodes. We can conclude that Golgi bodies are responsible for the
production and secretion of molecules related to the adhesion and formation of
cell wall membrane, also aiding in the
polarization and orientation of physodes. The fused physodes occupied much of
the cytoplasm, preventing other cytoplasmic processes, thus directly affecting
the development of this alga.