Figure 4
The MDP1 expression causes DNA compaction. (A) Fluorescence microscopic analysis of the cell and DNA morphology of AMI-mdp1 (MDP1) and AMI-NTD (NTD). After 24 h incubation of bacteria in the presence or absence of 0.2% Ace (indicated as 0.2% Ace or control, respectively), bacterial cells were stained with DAPI and then the cell and DNA (nucleoid) morphology (blue) were analyzed under fluorescence microscope. Bright field (Bright), DAPI-stained (DAPI), and merged (Merge) images of represented cells are shown. Scale bars: 10 µm. (B) TEM analysis of bacterial structures of AMI-mdp1 (MDP1) and AMI-NTD (NTD). Representative cell images in each group are shown. Arrows indicate nucleoid. Scale bars: 1 µm. (C) Distribution of the length of DAPI-stained DNA area of the cells detected in panel A (n ≥ 50). Open blue, AMI-NTD (−Ace, control); closed blue, AMI-NTD (+0.2% Ace); open black, AMI-mdp1 (−Ace, control); and closed black, AMI-mdp1 (+0.2% Ace). *P < 0.05. The result shown is a representative of at least three experiments. (D) Intracellular area occupied by DNA. Average lengths of DNA area under each condition of C were calculated. Percent intracellular area occupied by DNA is shown (gray). More than 100 cells were examined in each condition. Mean ± SD. *P < 0.05. (E) Fluorescence microscopic analysis of the cell and DNA morphology of AMI-mdp1 Mtb , analyzed as described in A. Scale bars: 10 µm. (F) Distribution of the length of DAPI-stained DNA area of the cells detected in panel E (n > 100). Open black, AMI-mdp1 Mtb (−Ace, control); and closed black, AMI-mdp1 Mtb (+0.2% Ace). *P < 0.05. The result shown is representative of at least two experiments. (G) Intracellular area occupied by DNA. Average lengths of DNA area under each condition of F were calculated as shown in panel D (n > 100). Mean ± SD. *P < 0.05.
