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. 2011 May;193(10):2619–2629. doi: 10.1128/JB.00120-11

Fig. 5.

Fig. 5.

pknE knockout mutant and overexpression strains have altered heterocyst development. Photomicrographs of filaments showing heterocyst formation in the wild type (WT) (A) and pknE knockout mutant strain AMC1763 (B) 24 h after nitrogen step-down. Strain AMC1765 contains extra copies of pknE expressed from its native promoter on plasmid pAM4146 and showed no heterocyst formation 24 h after nitrogen step-down (C). Strain AMC1764 contains plasmid pAM4378, which carries pknE expressed from the copper-inducible petE promoter, and showed elongated misshapen cells after 4 to 5 days of growth on nitrate-containing medium (D). All panels are the same magnification. Arrowheads indicate heterocysts. Bar, 10 μm.