Observation and analysis of single DNA nano-kinetics by pin-fiber video scope

Abstract

The nano-kinetic movement of a single DNA molecule was observed and analyzed by a newly developed video-microscope system with an optical fiber, called a pin-fiber video scope. A single lambda-DNA molecule was put in focus using fiber-illumination, and the stretching and shrinking motion was measured. The molecule's kinetics were analyzed by numerical calculations and are discussed. A photocleavage phenomenon of DNA molecules was also visualized by the pin-fiber video scope. The new video-microscope system has the potential to observe and analyze the nano-kinetics of a single molecule.

Enzyme-catalysed reaction for long-term fluorescent observation of single DNA molecules

“…In conclusion, we investigated the types of dyes and oxygen scavenging methods suited to long-term fluorescent observations of DNA molecules by making fluorescent measurements of single DNA molecule observations under diverse conditions. We found YOYO-1 was superior to YOPRO-1 in terms of long-term fluorescent observations, however, it is known that YOYO-1 undergoes photocleavage of DNA molecules when being irradiated by light; 22,29 this would prevent researchers from the long-term observation of DNA molecules. In terms of adoption as a fluorescent dye, consideration should be given not only to photobleaching but also to the photocleavage of DNA molecules.…”

Laser Speckle Microscope for Instantaneous Determination of Condition of Single Living Cell

“…The authors found that interference patterns of laser speckles on a single human living cell was easily recognized using a ''pin-fiber video microscope'' system we had developed. 6,7) Although human tissue and plant tissue observations have been reported to date, [8][9][10] to our knowledge, this is the first report of a single living human cell observation by laser speckle microscopy. In the experiment, it was found that by comparing a living cell with a fixed (dead) cell, the fluctuation activities of their laser speckle patterns were completely different.…”

“…The experimental setup was fundamentally identical to that in the pin-fiber video microscope system we had already reported. 6,7) Figure 1 shows a simple schematic of the apparatus. The sample on the stage of the microscope (Zeiss, Axioplan) was illuminated using a laser (Crystalaser, Model BCL-005-M, 5 mW, 473 nm, 0.1 nm linewidth, linear polarization) beam propagated through an optical fiber (Thorlabs, SM500).…”