Mitochondrial function in cell wall glycoprotein synthesis in Saccharomyces cerevisiae NCYC 625 (wild type) and [rho(0)] mutants

We studied phosphopeptidomannans (PPMs) of two Saccharomyces cerevisiae NCY C 625 strains (S, diastaticus): a wild type strain grown aerobically, anaer obically, and in the presence of antimycin and a [rho(0)] mutant grown aero bically and anaerobically, The aerobic wild-type cultures were highly flocc ulent, but all others were weakly flocculent, Ligands implicated in floccul ation of mutants or antimycin-treated cells were not aggregated as much by concanavalin A as were those of the wild type, The [rho(0)] mutants and ant imycin-treated cells differ from the wild type in PPM composition and inver tase, acid phosphatase, and glucoamylase activities. PPMs extracted from di fferent cells differ in the protein but not in the glycosidic moiety. The P PMs were less stable in mitochondrion-deficient cells than in wild-type cel ls grown aerobically, and this difference may be attributable to defective mitochondrial function during cell wall synthesis. The reduced flocculation of cells grown in the presence of antimycin, under anaerobiosis, or carryi ng a [rho(0)] mutation may be the consequence of alterations of PPM structu res which are the ligands of lectins, both involved in this cell-cell recog nition phenomenon. These respiratory chain alterations also affect peripher al, biologically active glycoproteins such as extracellular enzymes and per ipheral PPMs.