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. 2003 May;185(9):2887–2900. doi: 10.1128/JB.185.9.2887-2900.2003

FIG. 1.

FIG. 1.

(A) Lanes 1 and 2, biofilm formation assay of two S. gordonii::Tn917-lac mutants. Lane 1, a biofilm-positive mutant (growth = A575 of 1.1); lane 2, biofilm-defective adcR::Tn917-lac mutant (growth = A575 of 1.1). Panels 3 and 4, phase-contrast micrographs of biofilm formation on borosilicate coverslips in BM after 24 h by WT (panel 3) and adcR::Tn917-lac mutant (panel 4). Bar = 10 μm. Images represent what was observed in multiple fields. Lanes 5 and 6, Southern hybridization of KpnI-digested DNA from WT (lane 5) and adcR::Tn917-lac mutant (lane 6). DIG-labeled pTV32-OK containing Tn917-lac (which has one KpnI site) was used as the probe. (B to D) Gene organization in the adc operon in various streptococci. Genes from the adc operon are shown in grey. (B) S. gordonii adc operon. adcR (positions 261 to 704) encodes a putative transcriptional repressor for Mn-responsive expression, adcC (positions 701 to 1411) encodes a putative ATP-binding cassette (ABC) transporter, adcB (positions 1404 to 2210) encodes a putative ABC transporter (membrane protein), and adcA (positions 2220 to 3722) encodes a metal-binding lipoprotein, an ABC transporter. The black vertical arrow indicates the position of Tn917-lac insertion in the biofilm-defective mutant. (C) S. pneumoniae adc operon, consisting of adcR, adcC, adcB, and adcA. (D) S. mutans adc operon, consisting of adcR, adcC, and adcB. The adcA gene is present on a different part of the chromosome.