INVESTIGADORES
MORENO Silvia Margarita
artículos
Título:
Mucor rouxii ultrastructure: cAMP and actin cytoskeleton.
Autor/es:
PEREYRA,E., INGERFELD, M., ANDERSON, N., JACKSON, S.L. AND MORENO, S.
Revista:
PROTOPLASMA
Referencias:
Año: 2006 vol. 228 p. 189 - 199
ISSN:
0033-183X
Resumen:
A comparative analysis of the effect of two compounds, dibutyryl
cyclic-AMP (dbcAMP) and latrunculin B, on the morphology and
ultrastructure of the dimorphic fungus Mucor rouxii under aerobic growth
conditions is presented. dbcAMP acts through the sustained activation of
protein kinase A, and latrunculin B through the disruption of the actin cytoskeleton.
Upon addition of these compounds to the growth medium at
any stage of the germination process, cells lost polarised growth and
switched to isodiametric growth. The effect was reversible. The morphologies,
visualised by light microscopy or scanning electron microscopy
(SEM), were alike. A switch from a rough to a smooth surface was observed
by SEM when cells were repolarised by removal of the added compound.
Ultrastructural changes under both conditions, as observed by
transmission electron microscopy, were similar, the main feature being the
enlargement of the cell wall, with irregular depositions, and detachment
from the cell membrane. dbcAMP-treated cells showed a decrease in the
number of glycogen granules compared with control and latrunculin Btreated
cells. F-actin staining with fluorescein isothiocyanatephalloidin
showed that both dbcAMP- and latrunculin B-treated cells displayed a
much lower fluorescence than control cells, with only a few pale plaques.
The results suggest that the sustained activation of protein kinase A, which
impairs polarised growth, might exert its effect through a modification of
actin cytoskeleton organisation, very probably also involving an integrinlike
pathway, as judged by the cell wall detachment and loss of cell adhesiveness
of the dbcAMP-treated isodiametric cells.Mucor rouxii under aerobic growth
conditions is presented. dbcAMP acts through the sustained activation of
protein kinase A, and latrunculin B through the disruption of the actin cytoskeleton.
Upon addition of these compounds to the growth medium at
any stage of the germination process, cells lost polarised growth and
switched to isodiametric growth. The effect was reversible. The morphologies,
visualised by light microscopy or scanning electron microscopy
(SEM), were alike. A switch from a rough to a smooth surface was observed
by SEM when cells were repolarised by removal of the added compound.
Ultrastructural changes under both conditions, as observed by
transmission electron microscopy, were similar, the main feature being the
enlargement of the cell wall, with irregular depositions, and detachment
from the cell membrane. dbcAMP-treated cells showed a decrease in the
number of glycogen granules compared with control and latrunculin Btreated
cells. F-actin staining with fluorescein isothiocyanatephalloidin
showed that both dbcAMP- and latrunculin B-treated cells displayed a
much lower fluorescence than control cells, with only a few pale plaques.
The results suggest that the sustained activation of protein kinase A, which
impairs polarised growth, might exert its effect through a modification of
actin cytoskeleton organisation, very probably also involving an integrinlike
pathway, as judged by the cell wall detachment and loss of cell adhesiveness
of the dbcAMP-treated isodiametric cells.