Analysis of paromomycin resistance in wild type and transgenic G. pectorale strains. (A) After particle bombardment, treated organisms were distributed in Erlenmeyer flasks, aerated, and illuminated in a dark/light cycle. Paromomycin (1 μg/ml) was added after 48 h. (B) Appearance 12 days after particle bombardment exemplified by five flasks. (C) and (D): For detailed analysis of resistance, identical quantities of cells were incubated with increasing concentrations of paromomycin for eight days. (C) Analysis of wild type G. pectorale (upper row: 0–10 μg; lower row: 0–0.5 μg paromomycin/ml). (D) Analysis of transgenic strains (0–10 μg paromomycin/ml). (D1) Strains transformed with the selectable marker plasmids paphG (T-G...) or pPmr3 (T-J...). (D2) Strains co-transformed with the selectable marker plasmid pPmr3 along with the non-selectable plasmids ptubar4 (T-J...), pPsaD-GLuc (T-PL...), or pHsp70A-GLuc (T-HL...). (B-D) plus sign (+), flasks/vials with paromomycin-resistant green organisms; minus sign (-), cleared flasks/vials with some white remains of dead organisms.