TABLE 2.

Effect of PmSUC2 on expression of MAL genesa

Relevant MAL genotype (strain)PlasmidMaltose transport activitybMaltase activityc
G/LG/L + M0 h6 h
MAL61 MAL12 MAL13 (CMY1001)Vector0.175.6148576
mal61Δ MAL12 MAL13 (CMY1050)Vector0.090.112120
pPTE18 (PmSUC2)0.68NDd27706
pADH1-MAL61/HA5.98ND26643
mal61Δ MAL12 mal13Δ (CMY1061)Vector0.11ND2721
pPTE18 (PmSUC2)0.56ND1225
pADH1-MAL61/HA6.10ND1218
  • a Strains CMY1050 (MAL61Δ::HIS3) and CMY1061 (MAL611Δ::HIS3 MAL13Δ::G418) were transformed with plasmid pUN70, pPTE18 (PmSUC2), or pADH1-MAL61. Maltose transport activity was determined in early mid-log-phase cells grown in selective medium containing 3% glycerol and 2% lactate (G/L) or G/L plus 2% maltose (G/L + M). For maltase activity, cells were grown to early mid-log phase in selective synthetic medium containing G/L and then transferred to G/L + M. Maltase activity was determined at the time of transfer to maltose (0 h) and 6 h after the transfer. Maltase activity and transport activity were assayed as described in Materials and Methods. Experimental variation for maltose transport activity was <20%, and that for maltase activity was <30%.

  • b Maltose transport activity is expressed as nanomoles of maltose transported per milligram of cells per minute.

  • c Maltase activity is expressed as nanomoles of PNPG hydrolyzed per milligram of total protein per minute.

  • d ND, not determined.