Involvement of single-strand breaks in complex formation between single-stranded DNA and nucleoids of Bacillus subtilis

1984 ◽  
Vol 193 (3) ◽  
pp. 500-506
Author(s):  
Jan van Randen ◽  
Koos Wiersma ◽  
Gerard Venema
1972 ◽  
Vol 27 (6) ◽  
pp. 708-713 ◽  
Author(s):  
W. Köhnlein ◽  
F. Mönkehaus

Investigations on hybrid DNA of B. subtilis after irradiation with long wavelength UV (313 nm) indicate that single strand breaks are produced in the T-strand. These lesions are not observed in normal DNA. Since the action of diffusible photoproducts could be excluded the occurrence of single strand breaks in the T-strand may be due to intramolecular energy transfer. Measuring the breakage rates for the T- and B-strand by employing analytical ultracentrifugation it was found that up to 5% of the energy absorbed in the B-strand can be transferred to the T-strand and causes there single strand breaks. The breakage rates per erg-mm- 2 for single strand breaks after long wavelength UV are determined to be aT = 0.5 · 10-4 and aB = 10 · 10-4 breaks/106 Dalton for the T- and B-strand of hybrid DNA respectively.


2000 ◽  
Vol 66 (1) ◽  
pp. 199-205 ◽  
Author(s):  
Tony A. Slieman ◽  
Wayne L. Nicholson

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.


1977 ◽  
Vol 43 (6) ◽  
pp. 779-779
Author(s):  
Aritsune UCHIDA ◽  
Yoshihiko SAKO ◽  
Hajime KADOTA

Blood ◽  
1975 ◽  
Vol 46 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Y Hashimoto ◽  
F Takaku ◽  
K Kosaka

Abstract The size of single-stranded DNA in lymphocytes in GO stage from 22 patients with acquired primary and secondary aplastic anemia was estimated by alkaline sucrose gradient centrifugation. The average size was 9.3 (+/-0.3) times 10(7) daltons. The lymphocytes of patients contained significantly more single-strand breaks in DNA, compared to those of normal persons. The difference in size of single-stranded DNA which had been present in nontransformed lymphocytes could also be observed in transformed lymphocytes. Some characteristic differences could be observed in the sedimentation patterns of single-stranded DNA in the lymphocytes of patients with aplastic anemia and those of normal persons. The single-strand breaks in DNA suggested that the repair processes were disturbed in the DNA molecules of circulating lymphocytes from patients with acquired primary and secondary aplastic anemia.


Blood ◽  
1975 ◽  
Vol 46 (5) ◽  
pp. 735-742
Author(s):  
Y Hashimoto ◽  
F Takaku ◽  
K Kosaka

The size of single-stranded DNA in lymphocytes in GO stage from 22 patients with acquired primary and secondary aplastic anemia was estimated by alkaline sucrose gradient centrifugation. The average size was 9.3 (+/-0.3) times 10(7) daltons. The lymphocytes of patients contained significantly more single-strand breaks in DNA, compared to those of normal persons. The difference in size of single-stranded DNA which had been present in nontransformed lymphocytes could also be observed in transformed lymphocytes. Some characteristic differences could be observed in the sedimentation patterns of single-stranded DNA in the lymphocytes of patients with aplastic anemia and those of normal persons. The single-strand breaks in DNA suggested that the repair processes were disturbed in the DNA molecules of circulating lymphocytes from patients with acquired primary and secondary aplastic anemia.


Author(s):  
Magdy Y. Shamy ◽  
Hazem H. Osman ◽  
Kamal M. Kandeel ◽  
Nehad M. Abdel-Moneim ◽  
Khalid F. El Said

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