FM observations of w/w microdroplets entrapping single T4 GT7 DNA molecules.

The microdroplets are generated through phase separation of PEG/DEX (6 and 2.5 wt%) solution with a low DNA concentration (0.2 μM in nucleotide units) at different concentrations of SPD. The inner and outer solutions of the droplet are DEX-rich and PEG-rich, respectively. (A) Schematic representation of the experimental procedure to prepare the PEG/DEX micro-segregated solution in the presence of DNA. (B) Multiple T4 GT7 DNA molecules in w/w microdroplets at different concentrations of SPD. (C) Time-successive images are shown on the left side. Single T4 GT7 DNA molecules in w/w microdroplets exhibiting Brownian motion. The trajectories of DNA molecules for the period of Δt = 2 s between t = 6 s and t = 8 s are shown in right side.</p

Evaluation of the hydrodynamic radius <i>R</i>_H of T4 GT7 DNA molecules from an analysis of Brownian motion.

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Method of evaluation on the hydrodynamic radius <i>R</i>_H of DNA.

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Real-time observation of the folding transition of a single T4 GT7 DNA molecule in a w/w microdroplet.

(A) FM images reveal that, under thermal fluctuation, the conformation of a single DNA changes from an elongated coil to a compact globule. The solution composition was similar to that in Fig 1 in the presence of 0.2 mM SPD. The folding transition was generated spontaneously during FM observation of the droplet. (B) Corresponding quasi-3D profiles colored with the fluorescence intensity for the images in (A).</p

FM observation of w/w microdroplets entrapping several T4 GT7 DNA molecules.

The microdroplets were generated through phase separation of PEG/DEX solution under the conditions similar to those in Fig 1, except for the DNA concentration of 40 μM in nucleotide units. The total observation time is 10 s.</p

Opposite effect of polyamines on <i>In vitro</i> gene expression: Enhancement at low concentrations but inhibition at high concentrations - Fig 1

Chemical formulas of (A) spermidine, [SPD(3+)] and (B) spermine, [SP(4+)].</p

Gene expression efficiency depending on the DNA concentration at a fixed concentration of SPD(3+), 1.5 mM.

<p>Gene expression efficiency depending on the DNA concentration at a fixed concentration of SPD(3+), 1.5 mM.</p

Schematic representation of the nature of the interaction of polyamine with DNA and also with RNA polymerase depending on the polyamine concentration.

(A): elongated DNA without polyamine, (B): parallel alignment of DNA segments with the inset of the AFM image of Fig 5(C), (C): compact DNA with the inset of AFM of Fig 5(D).</p

AFM images of DNA conformations at different concentrations of SPD(3+).

SPD(3+) concentration is (A) 0.004 mM (control), (B) 0.1 mM, (C) 0.3 mM, and (D) 2 mM.</p

AFM images of DNA conformations at different concentrations of SP(4+).

<p>SP(4+) concentration is (A) 0.004 mM (control), (B) 0.007 mM, (C) 0.06 mM, and (D) 0.6 mM.</p