Colocalization of cortical microtubules and F-actin inDipodascus magnusii using confocal laser scanning microscopy

Abstract

Distribution of microtubules and F-actin in aerobically growing cells of Dipodascus magnusii, belonging to the class Saccharomycetes was analyzed using immunofluorescence microscopy and labeling with rhodamine-tagged phalloidin. A conspicuous system of permanent cytoplasmic microtubules was observed in association with multiple nuclei. In elongating cells, helices of cytoplasmic microtubules appeared at the cell cortex. In cells approaching cytokinesis transversely oriented microtubules were revealed at incipient division sites. Confocal laser scanning microscopy showed a continuity of these transverse microtubules with the remaining microtubule network. The actin system of D. magnusii consisted of patches and filaments. Patches were found to accumulate at the tips of growing cells. Bands of fine actin filaments were usually observed before F-actin rings were established. A close cortical association of microtubules with the F-actin ring was documented on individual optical sections of labeled cells. Cells with developing septa showed medial F-actin discs associated at both sides with microtubules. Colocalization of cytoplasmic microtubules with actin filaments at the cortex of dividing cells supports a role of both cytoskeletal components in controlling cell wall growth and septum formation in D. magnusii.

Formaldehyde fixation is detrimental to actin cables in glucose-depleted S. cerevisiae cells

“…Details remain to be elucidated. However, based on our experience from our earlier F-actin studies in fungi 44142434445, the occurrence of actin cables after formaldehyde-fixation could be stabilized by a short pre-incubation of cells with 30 mM EGTA before fixation. This suggests that formaldehyde before fixation may induce some uneven and general permeablization of intracellular membranes, thus significantly changing the intracellular homeostasis.…”

“…Cells grown in presence of glucose and glucose-depleted yeast cells were fixed with formaldehyde (final concentration 3.7 %) added to the medium for 30 minutes and stained for F-actin with rhodamine-tagged phalloidin (Rh-phalloidin; Molecular Probes) as described elsewhere 145. The cells were inspected after coating with a slice of 1.5 % agarose in the appropriate medium as described elsewhere 49.…”

Evolution of a domain conserved in microtubule-associated proteins of eukaryotes

“…Similar to other eukaryotes, the cytoskeleton of plant cells consists of tubulin and actin networks which render multiple morphological functions during various phases of cellular development, growth, and movement (Vassilyev 1996;Hasek et al 2003;Mathur 2004;Wasteneys and Yang 2004). Unlike animal cells, plant cells have prominent cell walls formed by networks of cellulose microfi brils, hemicelluloses, lignin, and structural proteins.…”