PubMed Health⌕ Search

Biomedical subjects

H Oana

Publications and source records attributed to H Oana.

7 recordsLinked to original sources
PubMed1999

Visualization of a specific sequence on a single large DNA molecule using fluorescence microscopy based on a new DNA-stretching method.

A method for analyzing large DNA which makes it possible to obtain spatial information on the positions of specific sequences along a DNA molecule has been developed. Making use of the fact that large DNA molecules are stably elongated under an alternating-current field in a concentrated linear polymer solution, the direct observation of elongated individual lambda DNA molecules with fluorescence probes was carried out using fluorescence microscopy. The spatial positions of the fluorescent spots of the probe (fluorescence-labeled restriction endonuclease EcoRI) on DNA molecules were determined by image analysis. As expected, fluorescent spots of EcoRI were observed at certain positions on lambda DNA, where sequences to which EcoRI binds are located. Finally, the potential application of single large DNA molecule analysis using this DNA-stretching method is discussed.

Bacteriophage lambda↗
PubMed1999

Single large DNA molecule analysis using fluorescence microscopy.

A large DNA analysis method which enable to obtain spatial information of positions of specific sequences along DNA molecule has been developed. Making use of the phenomenon that large DNA molecule is elongated stably under alternative current field in a concentrated linear polymer solution, direct observation of elongated individual lambda DNA molecules with fluorescence probes was carried out using fluorescence microscopy. Then, the spatial positions of the fluorescence spot of the probe on the DNA molecule were determined by image analysis.

Bacteriophage lambda↗
PubMed1998

High-speed separation of linear and supercoiled DNA by capillary electrophoresis. Buffer, entangling polymer, and electric field effects.

Capillary electrophoresis in dilute and semidilute (slightly entangled) hydroxyethyl cellulose (HEC) is shown to separate linear double-stranded DNA (ds-DNA) and supercoiled plasmid DNA in the size range 1-16 thousand base pairs in 3 min. The mobilities of linear ds-DNA fragments are stronger functions of electric field strength and buffer concentration than the mobilities of supercoiled plasmids. The effects of HEC concentration and molecular weight are similar for both forms of DNA. The behavioral differences, which are attributed to the greater stiffness of the plasmids, can be used to define conditions that maximize resolution of supercoiled and linear ds-DNA of the same or similar number of base pairs.

Buffers↗
PubMed1997

Capillary electrophoresis of supercoiled and linear DNA in dilute hydroxyethyl cellulose solution.

Capillary electrophoresis in dilute hydroxyethyl cellulose is shown to separate supercoiled DNA in the size range 2000-16,000 base pairs. The plasmids migrate more slowly than linear ds-DNA of the same sizes. Plasmid bandwidths are larger than observed for ds-DNA, allowing identification of the type of DNA by bandwidth. The differing dependence of mobility on chain length can be explained by assuming that a plasmid migrates as an elastic rod, while ds-DNA migrates as a wormlike chain.

Cellulose↗
PubMed1997

Reorientation of large DNA molecules in concentrated polyacrylamide solution during crossed-field electrophoresis.

Recently, we found that, in concentrated neutral solutions, DNA molecules migrate in linear conformation under steady electric field. In this paper, we report the conformational change of DNA during 120 degree crossed-field electrophoresis in the same polymer solution. We found that, in concentrated polyacrylamide solutions, the reorientation process of DNAs becomes simple: the DNA goes back along the previous track and the reorientation time is longer for larger DNA. Such a backtrack motion has been thought to be an essential motion for the separation of DNA fragments in pulsed field gel electrophoresis. We expect that this phenomenon is useful for a more efficient separation technique of large DNAs than the current pulsed field gel electrophoresis.

Acrylic Resins↗
PubMed1996

Conformational dynamics of DNA during biased sinusoidal field gel electrophoresis.

DNA motion during biased sinusoidal field gel electrophoresis around the antiresonance condition was investigated by direct observation using fluorescent microscopy and Brownian dynamics simulation. Time development of the center of mass velocity, vx, and the principal value of the gyration tensor, R1, was measured at this antiresonance condition. The typical stretch-contract motion, which is observed in steady field and at high frequency field, is severely suppressed, and there are two or more dominant kinks that compete with each other. Analysis of the kink motion from the simulation results supports this picture.

Bacteriophage T4↗