Initiation of Budding and Chitin-Ring

Abstract

Bud scar-rich preparation, which consisted mostly of crater-like bodies with some fragment of cell wall, was easily obtained from the isolated cell walls of baker's yeast by enzymic treatment under appropriate condition. In spite of low glucosamine content, which is due to the action of chitinase in the enzyme preparation, X-ray diffraction analysis showed that the structure of chitin was well preserved in this preparation.On the other hand, the preparation obtained by chemical treatment of intact yeast cells indicated high glucosamine content.Differing from the results of Bacon et al., the present preparation obtained after 2 cycles of chemical treatment still retained the original cellular shape with remnant cytoplasmic materials. After 5 cycles of the treatment, bud scar-rich fraction nearly equal to that obtained by enzymic treatmet was obtained.By the treatment of the bud scar-rich preparation with chitinase, the characteristic annular structure disappeared with concomitant decrease of glucosamine content, and at the same time, stainability with fluorescent dye, Brightener, of the annular structure disappeared.It was concluded that chitin is the intrinsic entity which constitutes the annular structure of the bud scar region and can be stained with Brightener.The appearance of stainable structures and buds together with the increase in cellular content of glucosamine was observed during culture of age 0 cells. The emergence of buds was preceded by the appearance of the stainable structures ; the increase of glucosamine content proceeded in accordance with the appearance of the annular structure. The morphological basis of the budding was discussed with special reference to the role of the annular structure.Budding yeast cell leaves a bud scar on the surface of mother cell after the daughter cell separated.Attentions were first directed on the conspicuous morphological feature of the bud scar.Many descriptions were made on its morphological structure either on the isolated cell walls or on the ultrathin sections of intact cells ; these are thoroughly described in several reviews (1-4). The number of bud scars of a cell, which corresponds to how many times the cell underwent budding in the past, can be counted by various means. The bud scars can be easily stained with some fluorescent dyes, so that the counting of stained bud scars under fluorescent microscope is the simplest 23

Selection of axial growth sites in yeast requires Axl2p, a novel plasma membrane glycoprotein.

“…To explore this phenotype further, the budding pattern of axl2 cells was examined. Spore progeny from three complete axl2-A1 ::HIS3/AXL2 tetrads were grown in liquid medium to early log phase, formaldehyde-fixed, and stained with Calcofluor white to visualize the chitin-rich bud scars that mark previous sites of budding (Hayashibe and Katohda 1973). Wild-type ( H i s ) haploid cells contain bud scars clustered at one end of the cell or as a trail across the surface (Fig.…”

Increase in Cell Size as a Measure of Growth of Saccharomyces Cerevisiae

“…Cellular divisional age was determined with fluorescent dye, Brightener, as described previously (13).…”

“…The number of budding was counted by the number of bud scar which was observed by staining with a fluorescent dye, Brightener, under a fluorescent phase-contrast microscope (13). The size of cells was measured on photomicrographs with at least 100 cells.…”

Crosslinks in the cell wall of budding yeast control morphogenesis at the mother–bud neck

“…Although the existence of the chitin ring had been known since the early 1970s (Hayashibe and Katohda, 1973;Cabib and Bowers, 1975), this was the first time that a function could be assigned to it. How could the effect of the ring be explained?…”