Linked Life Data

9537763

Source:http://linkedlifedata.com/resource/pubmed/id/9537763

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1998-4-6
pubmed:abstractText
The role of actin in apical growth and enzyme secretion in the filamentous fungus Aspergillus nidulans was studied by treating the hyphae with cytochalasin A (CA), which inhibits actin polymerization. Indirect immunofluorescence microscopy revealed actin at the tips of main hyphae and branches, and at the site of developing septa. CA inhibited the growth of the fungus and changed the growth pattern of hyphal tips from cylindrical tubes to spherical beads. The regions with swellings showed no actin fluorescence, and neither was actin seen in association with septa. After 4 h exposure, hyphae were able to resume the normal tip growth pattern in the presence of CA for a short period of time and new cylindrical hyphae, with actin fluorescence at the apex, emerged from the swollen tips. Later, the tips of the hyphae swelled again, which led to a beaded appearance. We also studied the effect of CA on the secretion of alpha- and beta-galactosidase. alpha-Galactosidase is secreted into the culture medium, whereas beta-galactosidase remains in the mycelium, with part of its activity bound to the cell wall. When A. nidulans mycelium was incubated in the presence of CA, a reduction in the secretion of alpha-galactosidase into the culture medium and a decrease in the alpha- and beta-galactosidase activities bound to the cell wall was detected. However, the CA dose used for the hyphae did not modify the secretion of the enzymes from protoplasts. Results described here provide evidence that a polymerized actin cytoskeleton is required for normal apical growth, hyphal tip shape and polarized enzyme secretion in A. nidulans. Cytochalasin-induced disruptions of the actin cytoskeleton could result in the alterations of apical growth and inhibition of enzyme secretion observed by blocking secretory vesicle transport to the apex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1350-0872
pubmed:author
pubmed:issnType
Print
pubmed:volume
144 ( Pt 1)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
45-53
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Effect of cytochalasin A on apical growth, actin cytoskeleton organization and enzyme secretion in Aspergillus nidulans.
pubmed:affiliation
Departament de Microbiología y Parasitología, Universidad de Alcalá de Henares, Madrid, Spain. mpampp@microb.alcala.es
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't