scholarly journals Two-Quantum Photoprocesses in DNA and RNA Biopolymers Under Powerful Picosecond Laser UV Irradiation

1984 ◽  
Vol 4 (1-6) ◽  
pp. 297-303 ◽  
Author(s):  
David N. Nikogosyan ◽  
Gagik G. Gurzadyan
Keyword(s):  
Uv Irradiation ◽  
Qualitative Difference ◽  
Picosecond Laser ◽  
Strand Breaks ◽  
Irradiation Intensity ◽  
Dna And Rna ◽  
Saturation Intensity ◽  
Phosphate Chain ◽  
Single Strand Breaks ◽  
Cross Links

Two-quantum photoreactions taking place under picosecond laser UV irradiation of DNA and RNA biopolymers were investigated. Despite of qualitative difference in two-step photoprocesses concerned (single-strand breaks formation in plasmid pBR 322 DNA, induction of breaks in TMV RNA sugar-phosphate chain, cross-links formation in DNA of CD phage) similar dependences of the quantum yield of the effects studied on the irradiation intensity can be observed with saturation in the region of 3 · 1011−3 · 1012 W/m2. The saturation intensity is one or two orders lower than in the case of irradiation of single monomers - nucleic acid bases.

scholarly journals The essential DNA polymerases delta and epsilon are involved in repair of UV-damaged DNA in the yeast Saccharomyces cerevisiae.

1999 ◽  
Vol 46 (2) ◽  
pp. 289-298 ◽  
Author(s):  
A Hałas ◽  
Z Policińska ◽  
H Baranowska ◽  
W J Jachymczyk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Uv Irradiation ◽  
Dna Polymerases ◽  
Relative Molecular Mass ◽  
Yeast Saccharomyces Cerevisiae ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Mutant Strains ◽  
Cellular Dna

We have studied the ability of yeast DNA polymerases to carry out repair of lesions caused by UV irradiation in Saccharomyces cerevisiae. By the analysis of postirradiation relative molecular mass changes in cellular DNA of different DNA polymerases mutant strains, it was established that mutations in DNA polymerases delta and epsilon showed accumulation of single-strand breaks indicating defective repair. Mutations in other DNA polymerase genes exhibited no defects in DNA repair. Thus, the data obtained suggest that DNA polymerases delta and epsilon are both necessary for DNA replication and for repair of lesions caused by UV irradiation. The results are discussed in the light of current concepts concerning the specificity of DNA polymerases in DNA repair.

Photoinduced Single Strand Breaks and Intrastrand Cross-Links in an Oligonucleotide Labeled with 5-Bromouracil

2014 ◽  
Vol 118 (19) ◽  
pp. 5009-5016 ◽  
Author(s):  
Magdalena Zdrowowicz ◽  
Barbara Michalska ◽  
Agnieszka Zylicz-Stachula ◽  
Janusz Rak
Keyword(s):  
Single Strand ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Cross Links

scholarly journals Artificial and Solar UV Radiation Induces Strand Breaks and Cyclobutane Pyrimidine Dimers in Bacillus subtilis Spore DNA

2000 ◽  
Vol 66 (1) ◽  
pp. 199-205 ◽  
Author(s):  
Tony A. Slieman ◽  
Wayne L. Nicholson
Keyword(s):  
Bacillus Subtilis ◽  
Uv Irradiation ◽  
Double Strand Breaks ◽  
Single Strand ◽  
Complex Spectrum ◽  
Cyclobutane Pyrimidine Dimers ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Pyrimidine Dimers ◽  
Solar Uv

ABSTRACT The loss of stratospheric ozone and the accompanying increase in solar UV flux have led to concerns regarding decreases in global microbial productivity. Central to understanding this process is determining the types and amounts of DNA damage in microbes caused by solar UV irradiation. While UV irradiation of dormant Bacillus subtilis endospores results mainly in formation of the “spore photoproduct” 5-thyminyl-5,6-dihydrothymine, genetic evidence indicates that an additional DNA photoproduct(s) may be formed in spores exposed to solar UV-B and UV-A radiation (Y. Xue and W. L. Nicholson, Appl. Environ. Microbiol. 62:2221–2227, 1996). We examined the occurrence of double-strand breaks, single-strand breaks, cyclobutane pyrimidine dimers, and apurinic-apyrimidinic sites in spore DNA under several UV irradiation conditions by using enzymatic probes and neutral or alkaline agarose gel electrophoresis. DNA from spores irradiated with artificial 254-nm UV-C radiation accumulated single-strand breaks, double-strand breaks, and cyclobutane pyrimidine dimers, while DNA from spores exposed to artificial UV-B radiation (wavelengths, 290 to 310 nm) accumulated only cyclobutane pyrimidine dimers. DNA from spores exposed to full-spectrum sunlight (UV-B and UV-A radiation) accumulated single-strand breaks, double-strand breaks, and cyclobutane pyrimidine dimers, whereas DNA from spores exposed to sunlight from which the UV-B component had been removed with a filter (“UV-A sunlight”) accumulated only single-strand breaks and double-strand breaks. Apurinic-apyrimidinic sites were not detected in spore DNA under any of the irradiation conditions used. Our data indicate that there is a complex spectrum of UV photoproducts in DNA of bacterial spores exposed to solar UV irradiation in the environment.

UV-induzierte Brüche in 5-Bromuracil-substituierter DNS des Phagen T1 / UV-Induced Strand Breaks in 5-Bromouracil Substituted DNA of Phage T1

1970 ◽  
Vol 25 (9) ◽  
pp. 1037-1042 ◽  
Author(s):  
G. Stephan ◽  
H. G. Miltenburger ◽  
G. Hotz
Keyword(s):  
Biological Activity ◽  
Uv Irradiation ◽  
Uv Light ◽  
Double Strand Breaks ◽  
Single Strand ◽  
Radical Scavenger ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Phage Dna ◽  
Site Of Action

Phage Tl and BU-Τ1 (phage DNA substituted with 5-bromouracil) were inactivated by UV-light (2537 A). After irradiation DNA was extracted and its sedimentation behaviour studied by zone centrifugation in neutral and alkaline sucrose gradients, respectively. In the DNA of unsubstituted phage no double-strand breaks and only a small number of single-strand breaks per inactivation dose could be detected after high UV-doses. However, after irradiation of phage BU-T1 double- and single-strand breaks were observed at an increased rate. UV-irradiation in the presence of a radical scavenger (0.01 M cysteamine) prevented the occurrence of double- but not of single strand breaks. The relevance of these breaks attributable to BU-incorporation for the biological activity (plaque forming ability) of the phage and the site of action of cysteamine are discussed.

scholarly journals 5-Bromo-2′-deoxycytidine—a potential DNA photosensitizer

2016 ◽  
Vol 14 (39) ◽  
pp. 9312-9321 ◽  
Author(s):  
Magdalena Zdrowowicz ◽  
Paweł Wityk ◽  
Barbara Michalska ◽  
Janusz Rak
Keyword(s):  
Single Strand ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Cross Links

Photoinduced single strand breaks and intrastrand cross-links are formed in an oligonucleotide labeled with 5-bromo-2′-deoxycytidine.

scholarly journals The integrity of deoxyribonucleic acid extracted from Escherichia coli 15T- after thymine-less death

1965 ◽  
Vol 97 (1) ◽  
pp. 240-246 ◽  
Author(s):  
BJ Smith ◽  
K Burton
Keyword(s):  
Escherichia Coli ◽  
Deoxyribonucleic Acid ◽  
Coli Strain ◽  
Single Strand ◽  
Aqueous Alkali ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Cross Links ◽  
Integrity Of Dna

1. The integrity of DNA extracted from Escherichia coli strain 15T(-) after thymine-less death was examined by studying the effects of treatment with aqueous alkali on the solubility in dilute acids and by viscosity and ultracentrifugal measurements, some of which were designed to detect single-strand breaks or inter-strand cross-links. None of the results showed that there was any modification or damage associated with thymine-less death.

Bromodeoxyuridine: a comparison of its photosensitizing and radiosensitizing properties

1988 ◽  
Vol 69 (3) ◽  
pp. 410-415 ◽  
Author(s):  
Corey Raffel ◽  
Dennis F. Deen ◽  
Michael S. B. Edwards
Keyword(s):  
Uv Light ◽  
Tumor Cell Line ◽  
Single Strand ◽  
Enhancement Ratio ◽  
Dose Enhancement ◽  
Content Type ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Cross Links

✓ The photo- and radiosensitizing properties of bromodeoxyuridine (BUdR) were assessed in vitro using the 9L rat brain tumor cell line. Pretreatment of 9L cells with 10 µM BUdR for 24 hours followed by irradiation with ultraviolet (UV) light resulted in a dose-enhancement ratio of 3.8:1 compared with UV radiation alone. X-radiation of BUdR-pretreated cells produced a dose-enhancement ratio of 1.7:1. Alkaline elution analysis of deoxyribonucleic acid (DNA) from cells treated with BUdR and UV irradiation showed the presence of DNA single-strand breaks and DNA-protein cross-links. Analysis of DNA from cells treated with BUdR and then x-irradiated showed no increase in DNA single-strand breaks compared with cells treated with x-radiation alone; no DNA-protein cross-links could be detected. The possible clinical relevance of these findings is discussed.

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