| Co-Investigator(Kenkyū-buntansha) |
FUKUDOME Kiyohiro Hiroshima U., Fac.Sci., Assistant, 理学部, 助手 (50183588)
OCHIAI Hiroshi Hiroshima U., Fac.Sci., Asst.Prof., 理学部, 助教授 (50033840)
YAMAMOTO Osamu Hiroshima U., Fac.Sci., Professor, 理学部, 教授 (80034627)
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| Research Abstract |
1. Design and Construction of the Apparatus
A novel high-speed pulsed electric dichroism spectrophotometer was designed and completed in this laboratory with the aid of the title grant as cited above, together with the computer softwares for connecting the high-voltage electric pulse delivery system and the optical detecting system with the spectrophotometer, which is abbreviated as the IMPAD-SPED (instant multichannel photodiode array detecting single-pulsed electric dichroism) spectrophotometer. This commercial spectrophtometer was, however, found to have an inherent drawback that is associated with the ultraviolet stray light below 300 nm. Attempts were made to remove this difficulty as well as a problem of the secondary emission from the image intensifier of the signal detector in collaboration with the manufacturer, but ended unsuccessfully. Thus, the quantitative measurement of electric linear dichroism spectra was limited to samples, such as DNA-dye complexes, which show strong a
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bsorption spectra in the visible and near UV (300-700 nm) regions.
2. Electric Linear Dichroism (ELD) Spectra Measurements
Ethidium bromide (EtBr) and the mono- and diacetylated derivatives, bound to sonicated and fractionated low molecular weight calf thymus DNA as well as large plasmid DNA,were studied with the IMPAD-SPED instrument. The ELD spectra showed that the plane of the bound dye is inclined as well as tilted with respect to the double-stranded DNA helical axis. Poly (A) ・Poly (U) -EtBr complexes are now being worked out for publication. A detailed analytical method of ELD spectra was developed for structural determination. With the conventional techniques, the B**Z transition of Poly (dG-dC) duplex and the triple helix formation of Poly (A) ・2Poly (I) were studied.
3. Presentation of Research Achievements
In the fiscal 1994 year, totally 7 papers were presented at scientific meetings of Polymer Society Japan, Colloid and Surface Chemistry Symposium, Biophysics Society of Japan, and Nucleic Acids Symposium. During the same period, totally 9 papers were published as shown in the reverse page. Less
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