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E Streiblová

Publications and source records attributed to E Streiblová.

At least 19 recordsLinked to original sources
PubMed2003

Colocalization of cortical microtubules and F-actin in Dipodascus magnusii using confocal laser scanning microscopy.

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.

Actins↗
PubMed1995

Changes in cell wall composition of deformed ras1- cells of Schizosaccharomyces pombe.

Disruption of the Schizosaccharomyces pombe ras1 gene results in a morphological transformation to large spheres, in contrast to wild-type cells which grow as rods. Chemical analysis of isolated cell walls showed no significant changes in saccharide content but an increase in protein and phosphate contents in ras1- walls relative to parent walls. Polymers tightly bound to the cell wall were solubilized by SDS treatment. Several compounds with molar mass ranging from 22 to 130 kDa and more were resolved by gel filtration and SDS-PAGE. Among low-molar-mass species, a component moving as a band at 31 kDa was conspicuous in ras1- cell walls. It was solubilized by heating in Tris-HCl buffer and shown to have a beta-1,3-glucanase activity against laminarin. The level of the enzyme was by 30% higher in the ras1- cell wall than in the wild-type cell wall. This enzyme may participate in the remodelling of the rigid glucan network and account (at least partially) for the aberrant cell shape. The ras1- cell wall contained a high level of charged polymers, especially phosphoproteins, raising the appealing possibility that ras1- is involved in a putative kinase cascade required to sense and respond to external stimuli destined for the cell wall. Although the present study shows that ras1 loss of function and altered cell wall composition are closely linked defects, it has still to be shown that the ras1 protein is directly involved in alterations found in the mutant cell walls.

Carbohydrates↗
PubMed1995

Yeast motor proteins.

Yeast accomplish a variety of intracellular motile events with the aid of mechanochemical enzymes known as motor proteins. This review covers the current state of knowledge on myosins, kinesins, dyneins, dynamins and SMC proteins present in yeast cells, and the most important developments in the study of yeast mitosis. Both topics have seen rapid progress over the past few years.

Cell Division↗
PubMed1992

Localization of a 210-kDa microtubule-interacting protein in the yeast Saccharomyces cerevisiae.

Using the monoclonal antibody MA-01, which recognizes a 210-kDa protein in cell-free extracts, spindle and cytoplasmic microtubules were visualized in budding yeast, Saccharomyces cerevisiae. In additional, a spot-like staining was found beneath the plasma membrane, revealing in part correlation with F-actin distribution. This pattern was common for cells of all cell-cycle stages. The interaction of the protein recognized by MA-01 with microtubules was confirmed in the double labeling with a polyclonal antitubulin antibody and by the sensitivity of intranuclear structures stained by MA-01 to the microtubule disrupting drug nocodazole.

Actins↗
PubMed1991

F-actin contractile rings in protoplasts of the yeast Schizosaccharomyces.

By rhodamine-phalloidin fluorescence, distinct continuous F-actin rings were visualized in 18-20% of the protoplasts of Schizosaccharomyces pombe and S. japonicus var. versatilis, in addition to randomly distributed F-actin dots. Whereas the reversion of ring-lacking protoplasts coincided with the polarization of the dotted F-actin pattern, the ring-containing protoplasts became furrowed as the F-actin rings constricted. The furrowing was more conspicuous in S. japonicus var. versatilis than in S. pombe protoplasts and it was blocked when the reversion was inhibited by Novozyme 234 indicating that the cell wall formation is essential for the F-actin ring constriction.

Actins↗
PubMed1987

Tubulin and actin topology during zygote formation of Saccharomyces cerevisiae.

The topology of tubulin and actin during mating of Saccharomyces cerevisiae was analysed by fluorescence microscopy with the monoclonal anti-tubulin antibody Tu01 and rhodamine-labelled phalloidin. Preconjugatory cells displayed an asymmetric distribution of the microtubule and actin cytoskeleton and an overall polarization of the cells preceding cell fusion. Prior to karyogamy, the haploid spindle pole bodies were associated with abundant cytoplasmic microtubules. Budding zygotes revealed the same tubulin and actin patterns as vegetative cells. Treatment of the mating mixture with the microtubule inhibitor nocodazole (10 micrograms ml-1) did not prevent polarization and fusion of haploids, zygote formation and emergence of the first zygotic bud. In marked contrast, the migration of the nucleus in preconjugatory cells as well as nuclear migration and fusion within the zygotes was unequivocally blocked by the action of the drug. It is suggested that the problem of the morphogenesis of mating should be approached by considering interactions at the cell periphery.

Actins↗
PubMed1986

Immunofluorescence of the microtubular skeleton in growing and drug-treated yeast protoplasts.

The microtubular system in growing protoplasts of Saccharomyces uvarum was visualized by immunofluorescence using the monoclonal antitubulin antibody TU 01. We confirmed the coexistence of regular spindle configuration and extensive cytoplasmic networks in growing protoplasts and also observed a distinct distortion of cytoplasmic microtubules in association with wall removal. After a short period for recovery of protoplasts in nutrient medium a restitution of cytoplasmic microtubules and their resumed contact with the protoplast surface was observed. Treatment of growing protoplasts with nocodazole resulted in the disappearance of spindle and cytoplasmic microtubules in the relevant fraction of the protoplast population. In carbendazime (MBC)-arrested protoplasts spindle microtubules were absent but cytoplasmic microtubules associated with spindle pole bodies were clearly visible. Microtubule reassembly on spindle pole bodies occurred within 30 min after washing out nocodazole as well as carbendazime. The approach using protoplasts suggests a simple way in which the differential effect of antimicrotubule agents can be experimentally tested and the microtubule organizing activity of yeast protoplasts visualized at the population level.

Benzimidazoles↗
PubMed1985

The cytoskeleton and control of the yeast cell cycle.

Recently the concept of eukaryotic cell cycle regulation has changed enormously because of the development of new concepts and techniques applied in studying the yeast cell cycle. Experimental facts and speculations are presented here, with emphasis on the role of the cytoskeleton in the control of division in yeast cells.

Cell Cycle↗
PubMed1984

Septum pattern in ts mutants of Schizosaccharomyces pombe defective in genes cdc3, cdc4, cdc8 and cdc12.

Septum-defective mutants of Schizosaccharomyces pombe impaired in cdc genes 3, 4, 8 and 12 were compared by fluorescence microscopy, freeze-etching and ultrathin sectioning. This approach made it possible to recognize the internal organization of defective phenotypes under restrictive conditions. Of special interest in this study was the pattern of unusual septum malformations found to be regular features of the terminal phenotypes of the mutants. Their overall topology was visualized at the cellular level by primulin fluorescence. The subcellular location of septum defects was found to be identical in origin to the compartment where normal septum was assembled in the wild type. Delocalized septation involved both microfibrillar and matrix components, which participated in the final assembly of malformations. Unique contour views of delocalized septa were exposed by freeze-fracturing. Cytoplasmic microtubules and microfilaments were detected in ultrathin sections of the cytoplasm of mutant cells. The internal organization of malformation-accumulating phenotypes suggested a disruption of the directional mechanism that steers septum material to the periplasm at the cell equator.

Ascomycota↗
PubMed1980

Microfilaments and cytoplasmic microtubules in cell division cycle mutants of Schizosaccharomyces pombe.

The occurrence of axial cytoplasmic microtubules (25 nm in diameter) and of microfilaments (7 nm in diameter) associated in bundles just below the plasma membrane of the yeast Schizosaccharomyces pombe is described. Both types of cytoplasmic filamentous structures were present in the cell division cycle mutant cdc 12-112 of this fungus incubated for 6 h at the restrictive temperature of 35 degrees C. Microtubules and microfilaments probably function in septum formation and (or) in the volume-related control of the terminal phenotype of the mutant.

Ascomycota↗
PubMed1978

Fine structure of imbibed sclerotial cells of Claviceps purpurea (Fr.) Tul revealed by freeze-etching.

The fine structure of the cortex of the natural sclerotium of Claviceps purpurea was studied. The cell wall of sclerotial cells is thickened due to overproduction of the fibrillar component of the wall. The intracellular spaces of the cortex tissue form a continuous system which is apparently instrumental in mediating communication between the growing sclerotium and the external milieu. The cytoplasmic membrane of imbibed sclerotial cells carriers abundant signs of secretory activity. Secretion vesicles, the content of which is discharged into external space, apparently contain exo 1,3-glucanase. Cytoplasmic vesicles migrating toward the plugged pores of the thickened septa apparently involve hydrolase secretion too. Spherosomes with lipid content are a predominant component of the cytoplasm of sclerotial cells. The activity of the membrane systems of imbibed cells indicates that the mobilization of lipids sets in only after activation of the hydrolases. Findings of phagocytosis of lipid granules by vacuoles are relatively frequent so that lipolysis might proceed in the vacuoles. Alkaloids could not be detected with the aid of freeze-etching.

Cell Wall↗
PubMed1975

Role of cell wall topography in conjugation of Schizosaccharomyces pombe.

The surface of the zygotes of Schizosaccharomyces pombe was studied by observing fluorescence following primulin treatment. Conjugation occurred only at the poles. Competence to fuse was independent of actual pole growth and pole ontogeny (old or new pole). The cells were competent to fuse throughout the first three-quarters of the cell cycle. Morphological criteria indicate that cell pairs are not synchronized at the moment of fusion. The length of the G1 phases of individual conjugating cells apparently ranges from 0.1 to 0.7 of the cell cycle duration.

Anthocyanins↗
PubMed1968

Surface structure of yeast protoplasts.

The fine structure of the yeast cell wall during protoplast formation was studied by means of phase-contrast microscopy and the freeze-etching technique. The freeze-etching results indicated that at least in some cases the entire wall substance was not removed from the surface of the protoplasts. After a treatment of 30 min to 3 hr with 2% snail enzymes, an innermost thin wall layer as well as remnants of the fibrillar middle layer sometimes could be demonstrated.

Cell Membrane↗