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Does DNA exert an active role in generating cell-sized spheres in an aqueous solution with a crowding binary polymer?

Tsumoto K, Arai M, Nakatani N, Watanabe SN, Yoshikawa K - Life (Basel) (2015)

Bottom Line: DNA molecules were selectively located in the interior of dextran-rich micro-droplets, when the composition of an aqueous two-phase system (ATPS) was near the critical condition of phase-segregation.The resulting micro-droplets could be controlled by the use of optical tweezers.A hypothetical scenario for the emergence of a primitive cell with DNA is briefly discussed.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Mie University, Mie, 514-8507, Japan. tsumoto@chem.mie-u.ac.jp.

ABSTRACT
We report the spontaneous generation of a cell-like morphology in an environment crowded with the polymers dextran and polyethylene glycol (PEG) in the presence of DNA. DNA molecules were selectively located in the interior of dextran-rich micro-droplets, when the composition of an aqueous two-phase system (ATPS) was near the critical condition of phase-segregation. The resulting micro-droplets could be controlled by the use of optical tweezers. As an example of laser manipulation, the dynamic fusion of two droplets is reported, which resembles the process of cell division in time-reverse. A hypothetical scenario for the emergence of a primitive cell with DNA is briefly discussed.

No MeSH data available.


Direct observation of growth of a dextran microdroplet around a core of DNA aggregates trapped under laser radiation. Times after trapping are indicated. A growing dextran droplet became a cell-like structure containing DNAs inside at 50 s. Dextran and PEG are 1.5% and 7% PEG, respectively. Bar: 10 µm.
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life-05-00459-f005: Direct observation of growth of a dextran microdroplet around a core of DNA aggregates trapped under laser radiation. Times after trapping are indicated. A growing dextran droplet became a cell-like structure containing DNAs inside at 50 s. Dextran and PEG are 1.5% and 7% PEG, respectively. Bar: 10 µm.

Mentions: These results raise the question of how such DNA-entrapping dextran microdroplets emerge. Most plausibly, DNA might enter dextran microdroplets that have already formed due to the exclusionary effects of PEG solutions. Alternatively, dextran microspheres might emerge and grow larger around cores of DNA aggregates. Interestingly, dextran apparently gathered to form a spherical shape around DNA molecules that were trapped under laser radiation in PEG solutions (Figure 5). Figure 1 shows that, near a critical point/binodal curve, the behavior of such a binary polymer solution can be easily influenced by a change in the environment, such as a change in temperature. Thus, it could be implied that if heating by a laser that traps DNA aggregates induces micrometer-scale phase separation of dextran, dextran must be concentrated around the aggregates through apparent affinitive interactions.


Does DNA exert an active role in generating cell-sized spheres in an aqueous solution with a crowding binary polymer?

Tsumoto K, Arai M, Nakatani N, Watanabe SN, Yoshikawa K - Life (Basel) (2015)

Direct observation of growth of a dextran microdroplet around a core of DNA aggregates trapped under laser radiation. Times after trapping are indicated. A growing dextran droplet became a cell-like structure containing DNAs inside at 50 s. Dextran and PEG are 1.5% and 7% PEG, respectively. Bar: 10 µm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390863&req=5

life-05-00459-f005: Direct observation of growth of a dextran microdroplet around a core of DNA aggregates trapped under laser radiation. Times after trapping are indicated. A growing dextran droplet became a cell-like structure containing DNAs inside at 50 s. Dextran and PEG are 1.5% and 7% PEG, respectively. Bar: 10 µm.
Mentions: These results raise the question of how such DNA-entrapping dextran microdroplets emerge. Most plausibly, DNA might enter dextran microdroplets that have already formed due to the exclusionary effects of PEG solutions. Alternatively, dextran microspheres might emerge and grow larger around cores of DNA aggregates. Interestingly, dextran apparently gathered to form a spherical shape around DNA molecules that were trapped under laser radiation in PEG solutions (Figure 5). Figure 1 shows that, near a critical point/binodal curve, the behavior of such a binary polymer solution can be easily influenced by a change in the environment, such as a change in temperature. Thus, it could be implied that if heating by a laser that traps DNA aggregates induces micrometer-scale phase separation of dextran, dextran must be concentrated around the aggregates through apparent affinitive interactions.

Bottom Line: DNA molecules were selectively located in the interior of dextran-rich micro-droplets, when the composition of an aqueous two-phase system (ATPS) was near the critical condition of phase-segregation.The resulting micro-droplets could be controlled by the use of optical tweezers.A hypothetical scenario for the emergence of a primitive cell with DNA is briefly discussed.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Engineering, Mie University, Mie, 514-8507, Japan. tsumoto@chem.mie-u.ac.jp.

ABSTRACT
We report the spontaneous generation of a cell-like morphology in an environment crowded with the polymers dextran and polyethylene glycol (PEG) in the presence of DNA. DNA molecules were selectively located in the interior of dextran-rich micro-droplets, when the composition of an aqueous two-phase system (ATPS) was near the critical condition of phase-segregation. The resulting micro-droplets could be controlled by the use of optical tweezers. As an example of laser manipulation, the dynamic fusion of two droplets is reported, which resembles the process of cell division in time-reverse. A hypothetical scenario for the emergence of a primitive cell with DNA is briefly discussed.

No MeSH data available.