Ultrastructure Of Yeast Cells Research Articles

On the Ultrastructure of Yeast Cells

Summary: The ultrastructure of yeast cells was first studied in 1957 and the techniques used since then have advanced greatly; an overview of the methods is first presented in this minireview. We achieved high-pressure freezing(HPF)fixation for yeast and developed HPF at ultra-low temperature which required using low voltage SEM(ULT-LVSEM)and immunoelectron microscopy. The cell wall biogenesis of the fission yeast Schizosaccharomyces pombe was defined using this technique. The high quality image of HPF. EULT-LVSEM showed an ultrastructure corresponding to a thin sectioned cell and could be observed three dimensionally from the outside and inside of the cell, allowing the initial septum formation to be seen. Using the antibodies of glucans from this yeast, the cells displayed in situ localization of glucans in the cell wall and Golgi apparatus, and their behavior during septum formation. Highly branched. β-1, 6-glucan was not detected in the first step, but all other glucans, . β-1, 3-and.a-1, 6-glucan, appeared throughout the septum until the secondary septum was formed. Accompanying septum formation the actin was located at the tip of the invaginated cell membrane and also accumulated at the contracted ring in the cell. From these facts it is concluded that the actin cytoskeleton governs septum formation during cell division.

Contrast Enhancement by Ruthenium Tetroxide for Observation of the Ultrastructure of Yeast Cells

To reveal the ultrastructure of regenerating protoplasts of Schizosacchgaromyces pombe, samples were treated with ruthenium tetroxide (RuO 4 ) after conventional fixation and then observed with a transmission electron microscope. Ruthenium tetroxide treatment was very effective for observing the ultrastructure. The treatment provides electron-dense and clear images of glucan fibrils developing from the protoplast surface. The filasomes, Golgi apparatus, and secretory vesicles with high-electron density were also observed in the cytoplasm

Antimicrobial activity of alkaloids from amphibian venoms and effects on the ultrastructure of yeast cells

The alkaloids samandarone, samandarine, samandaridine, spinaceamine, 6-methyl-spinaceamine and bufotenine, isolated from the skin gland secretions of Salamandra maculosa and Leptodactylus pentadactylus showed in screening tests a more or less specific bactericidal and/or fungicidal activity in concentrations varying from 3·0 × 10 −5 to 1·5 × 10 −6 M/ml. Electron microscopic studies on thin sections of Saccharomyces cerevisiae following treatment with Salamandra toxins showed that signs of lysis appear in the cytoplasm and in extensive regions of the cytoplasmic membrane.