FIGURE 5.

Poly-3-hydroxybutyrate contents of phaP mutants complemented with plasmids harboring phaP1 and phaP2. (A) H. seropedicae strains conjugated with pLPA01 were complemented with phaP1 in trans under control of its native promoter. The strains conjugated with pLPA02 were complemented with phaP2 in trans under control of its native promoter. Cells harboring pLPA01 or pLPA02 were grown in liquid NFb containing 37 mM _DL-malate and 20 mM NH₄Cl at 30°C. When the OD₆₀₀ of the cultures reached 1.0, 10 mL was removed to determine the PHB content by gas chromatography as described in section “Materials and Methods.” The bars marked with different letters indicate means significantly different (independent two-sample t-test, p < 0.05). Experiments were performed in quadruplicate. (B) Cells of ΔphaP1.2 mutant complemented with pLPA01 were stained with Nile Red and visualized by excitation with 543 nm light. Strains harboring pBBR1MCS-3 (C) or pLPA01 (D) were grown in NFb medium with 20 mM of ammonium chloride and 25 mM (w/v) _D-glucose at 30°C (orbital agitation at 120 rpm). OD₅₉₅ growth data were obtained from three independent cultures.