S. cerevisiae–E. coli chimeras have a partially rescued respiration-competent phenotype. S. cerevisiae–E. coli chimeras have a partially rescued respiration-competent phenotype. (A) Growth of S. cerevisiae cox2-60–E. coli chimeras on medium containing glycerol as the sole carbon source, selection medium III. No growth was observed for parent cox2-60 yeast lacking intracellular E. coli (control). Three different chimera colonies growing during successive rounds of plating are shown for each S. cerevisiae–E. coli chimera. Number of E. coli genomes per one yeast genome was determined by qPCR for E. coli ΔthiC chimeras from the fourth round of growth. (B) A single cell suspension of S. cerevisiae cox2-60–E. coli nadA chimera culture formed a comparable number of colonies on nonselective (YPD) and selective medium (selection medium II) plates. (C) Total DNAs isolated from colonies grown on selection medium II in B contain E. coli-encoded gfp gene. Ten random colonies (labeled 1–10) were PCR amplified for presence of gfp and MATa genes. Angad P. Mehta et al. PNAS 2018;115:46:11796-11801 ©2018 by National Academy of Sciences