Chitin structures of the cell walls of synchronously grown virgin cells of Saccharomyces cerevisiae

Abstract

The ability of a lytic b-glucanase of Arthrobacter GJM-1 to dissolve cell walls of Saccharomyces cereuisine with exception of the chitin-containing fraction was employed for the isolat,ion of chitin-rich residues of the cell walls of synchronously growing populations of virgin cells. Electron microscopical examination of such wall residues isolated from cells a t various stages of the budding cycle showed that the first phase of chitin deposition in the wall corresponds to the formation of a n annular structure found as a part of the bud scar after cell division. The annular chitin-rich structure could not be isolated at cell cycle stages preceding the bud emergence and at earliest stages of bud development. The observations confirmed that the annular structure (chitin ring) formed during bud growth represents a major part of total chitin present in the bud scar after septum closure.

Changes in DNA double-strand break repair during aging correlate with an increase in genomic mutations

“…1B, C; Supplemental Fig. S1B) (Vrsanská et al 1979). Cells in the oldest culture, O3, averaged ~ 17 bud scars (Fig.…”

Changes in DNA double-strand break repair during aging correlate with an increase in genomic mutations

“…Haploid yeast average ~25 divisions during their lifespan (Mortimer & Johnston 1959), and the number of cellular divisions was determined by counting the number of bud scars on the surface of the mother cell visualized by calcofluor white, which labels chitin encircling the site of budding (Figure 1b; Supplementary Figure 1b) (Vrsanská et al 1979). O3-aged cells were propagated for 66 hours and had an average of ~ 17 bud scars (Figure 1b).…”