UV-Empfindlichkeit von λ-Phagen mit variablem Bromuracil-Gehalt / UV-Sensitivity of λ-Phages with Various BU-Contents

1974 ◽  
Vol 29 (5-6) ◽  
pp. 289-293 ◽  
Author(s):  
Friedrich Mönkehaus
Keyword(s):  
Short Wavelength ◽  
Buoyant Density ◽  
Dna Bases ◽  
Density Measurements ◽  
Long Wavelength ◽  
E Coli ◽  
Uv Sensitivity ◽  
Sensitivity Loss ◽  
Cscl Density Gradient ◽  
Dna Strands

Heat induction of E. coli CR 34 (λcI857)/λ growing in media with variing bromouracil (BU)-contents yielded A-phages with different amounts of BU in their DNA-strands. The percentage substitution of thymine was determined by buoyant density measurements in a CsCl-density gradient. After irradiation of the phages with long wavelength UV (302/313 nm) and short wavelength UV (254 nm) the sensitivity (loss of infectivity) was determined as a function of the degree of BU-substitution. It was found that after irradiation with long wavelength UV the cross section is proportional to the percentage BU-substitution, whereas after irradiation with short wavelength UV it is not. The results can be explained by assuming energy transfer from the four DNA-bases to the BU.

Einfluß von Cysteamin auf die UV-Empnndlichkeit von λ-Phagen mit variablem Bromuracil-Gehalt / Influence of Cysteamine on the UV-Sensitivity of λ-Phages with Various BU-Contents

1974 ◽  
Vol 29 (5-6) ◽  
pp. 286-288
Author(s):  
Friedrich Mönkehaus
Keyword(s):  
Energy Transfer ◽  
Dose Reduction ◽  
Cross Section ◽  
Short Wavelength ◽  
Uv Light ◽  
Reduction Factor ◽  
Long Wavelength ◽  
Uv Sensitivity ◽  
Transfer Processes ◽  
Dna Strands

λ-Phages with different amounts of BU in their DNA-strands were irradiated with long wave­ length UV light (302/313 nm) and short wavelength UV-light (254 nm) in the presence and ab­ sence of cysteamine. It was found that the dose reduction factor is dependent on the percentage BU-substitution only after irradiation with UV-light of 254 nm, not after long wavelength UV-irradiation. Furthermore, the inactivation cross section is proportional to the BU-content of the DNA after irradiation with long and with short wavelength UV-light in the presence of cysteamine. The results lead to the conclusion that the presence of cysteamine inhibits energy transfer processes which occur after irradiation with UV-light of 254 nm in the absence of cysteamine.

scholarly journals A biophysical and structural analysis of DNA binding by oligomeric hSSB1 (NABP2/OBFC2B)

2020 ◽  
Author(s):  
Serene El-Kamand ◽  
Slobodan Jergic ◽  
Teegan Lawson ◽  
Ruvini Kariawasam ◽  
Derek J. Richard ◽  
...  
Keyword(s):  
Dna Binding ◽  
Oxidative Dna Damage ◽  
Genomic Stability ◽  
Dna Binding Protein ◽  
Oxidative Modification ◽  
Dna Bases ◽  
Genome Integrity ◽  
Oligomeric Proteins ◽  
Ssdna Binding ◽  
Dna Strands

AbstractThe oxidative modification of DNA can result in the loss of genome integrity and must be repaired to maintain overall genomic stability. We have recently demonstrated that human single stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) plays a crucial role in the removal of 8-oxo-7,8-dihydro- guanine (8-oxoG), the most common form of oxidative DNA damage. The ability of hSSB1 to form disulphide-bonded tetramers and higher oligomers in an oxidative environment is critical for this process. In this study, we have used nuclear magnetic resonance (NMR) spectroscopy and surface plasmon resonance (SPR) experiments to determine the molecular details of ssDNA binding by oligomeric hSSB1. We reveal that hSSB1 oligomers interact with single DNA strands containing damaged DNA bases; however, our data also show that oxidised bases are recognised in the same manner as undamaged DNA bases. We further demonstrate that oxidised hSSB1 interacts with ssDNA with a significantly higher affinity than its monomeric form confirming that oligomeric proteins such as tetramers can bind directly to ssDNA. NMR experiments provide evidence that oligomeric hSSB1 is able to bind longer ssDNA in both binding polarities using a distinct set of residues different to those of the related SSB from Escherichia coli.

scholarly journals Röntgenspektroskopische Untersuchung der chemischen Bindung in Oxiden

1967 ◽  
Vol 22 (9) ◽  
pp. 1401-1407 ◽  
Author(s):  
Hans-Ulrich Chun ◽  
Dieter Hendel
Keyword(s):  
Fine Structure ◽  
Metal Atom ◽  
Short Wavelength ◽  
The Other ◽  
Main Line ◽  
Ionic Character ◽  
Long Wavelength ◽  
Short Wavelength Side ◽  
Oxygen Bond ◽  
Wavelength Side

This paper reports about the fine structure in the O—K-spectra of the oxides BeO, MgO, CaO, SrO, BaO, Sc2O5, Y2O3, La2O3, Sm2O3, Yb2O3, NiO and ZnO. The spectra show the satellite lines α3, α4, α5, α6 on the short wavelength side of the main line α1,2 and a shoulder β′ on its long wavelength side. The wavelengths of all lines depend on the nature of the oxide. For the positions of the lines Kα1.2 in the spectra no systematic relation to other data of the oxides is observed. On the other hand the distance of the a4-satellite from the α1,2-line decreases with increasing electronegativity of the metal atom in the oxide. This distance can be used as a measure for the ionic character of the metal-oxygen bond in these compounds.

scholarly journals The IUE Ultraviolet Spectrum of PC 11

1993 ◽  
Vol 155 ◽  
pp. 398-398 ◽  
Author(s):  
M. Parthasarathy ◽  
S.R. Pottasch ◽  
J. Clavel
Keyword(s):  
Short Wavelength ◽  
Planetary Nebula ◽  
Significant Variation ◽  
Central Star ◽  
Ultraviolet Spectrum ◽  
Emission Lines ◽  
Symbiotic Star ◽  
Iras Source ◽  
Long Wavelength ◽  
Cold Dust

PC 11 (HD 149427, PK 331-5 1) is classified as a young planetary nebula with strong OIII 4363Å and a Zanstra temperature of TZ = 27000K. It is also classified as (D′ — type) yellow symbiotic star with A — F type companion. It is an IRAS source with detached cold dust with far intrared (IRAS) colours similar to planetary nebulae. The IUE short wavelength (SWP) spectra show emission lines due to OIII] (1661/1666Å). NIII] (1746/1754Å) CIII] (1907/1909Å). The OIII] and NIII] emission lines show significant variation. Variation in the strength of CIII] is not very significant. The strength of OIII] has decreased and NIII] has increased. The long wavelength (LWP) spectrum shows stellar continuum (A-F) and absorption lines due Mg II 2800Å feature. It also show emission lines at 2772Å (?) 3133Å −3140Å (very strong) (OIII, [FeV], 3209Å (He II?) ([FEII]). The variation in the strength of emission line due OIII] and NIII] and the presence of stellar continuum (A-F) suggests that the central star of PC 11 is a binary.

Why do Laplace-domain waveform inversions yield long-wavelength results?

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. R167-R173 ◽  
Author(s):  
Wansoo Ha ◽  
Changsoo Shin
Keyword(s):  
Short Wavelength ◽  
Field Data ◽  
Moving Average ◽  
Data Sets ◽  
Virtual Source ◽  
Laplace Domain ◽  
Long Wavelength ◽  
Velocity Models ◽  
Gradient Direction ◽  
Domain Inversion

Laplace-domain inversions generate long-wavelength velocity models from synthetic and field data sets, unlike full-waveform inversions in the time or frequency domain. By examining the gradient directions of Laplace-domain inversions, we explain why they result in long-wavelength velocity models. The gradient direction of the inversion is calculated by multiplying the virtual source and the back-propagated wavefield. The virtual source has long-wavelength features because it is the product of the smooth forward-modeled wavefield and the partial derivative of the impedance matrix, which depends on the long-wavelength initial velocity used in the inversion. The back-propagated wavefield exhibits mild variations, except for near the receiver, in spite of the short-wavelength components in the residual. The smooth back-propagated wavefield results from the low-wavenumber pass-filtering effects of Laplace-domain Green’s function, which attenuates the high-wavenumber components of the residuals more rapidly than the low-wavenumber components. Accordingly, the gradient direction and the inversion results are smooth. Examples of inverting field data acquired in the Gulf of Mexico exhibit long-wavelength gradients and confirm the generation of long-wavelength velocity models by Laplace-domain inversion. The inversion of moving-average filtered data without short-wavelength features shows that the Laplace-domain inversion is not greatly affected by the high-wavenumber components in the field data.

scholarly journals Regularities in the E. coli promoters composition in connection with the DNA strands interaction and promoter activity

2006 ◽  
Vol 7 (12) ◽  
pp. 969-973
Author(s):  
Andrey Yu Berezhnoy ◽  
Yuriy G. Shckorbatov ◽  
Kiryu Hisanori
Keyword(s):  
Promoter Activity ◽  
E Coli ◽  
Dna Strands
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