scholarly journals Photosensitized one-electron oxidation of DNA

2005 ◽  
Vol 77 (6) ◽  
pp. 963-975 ◽  
Author(s):  
Kiyohiko Kawai ◽  
Tetsuro Majima
Keyword(s):  
Dna Damage ◽  
High Performance ◽  
Transient Absorption ◽  
Basic Mechanism ◽  
Absorption Measurement ◽  
Mechanistic Study ◽  
Hole Transfer ◽  
Damage Quantification ◽  
Oxidation Of Dna ◽  
Kinetics Of

Photosensitized one-electron oxidation of DNA has attracted much interest because it causes oxidative damage which leads to mutation, and because it is involved in the basic mechanism of photodynamic therapy. In the present article, we describe the mechanistic study of photosensitized DNA damage, especially addressing the kinetics of hole transfer by adenine(A)-hopping and its effect on the DNA damage. The combination of the transient absorption measurement and DNA damage quantification by high-performance liquid chromatography clearly demonstrate that the yield of the DNA damage correlates well with the lifetime of the charge-separated state caused by A-hopping, showing that hole transfer helps DNA damage. These findings led us to propose a new method to accomplish the efficient DNA damage using a combination of two-color, two-laser irradiation.

Kinetics of Multistep Hole Transfer in DNA by Monitoring the Transient Absorption of the Pyrene Radical Cation

2003 ◽  
Vol 107 (50) ◽  
pp. 14052-14057 ◽  
Author(s):  
Tadao Takada ◽  
Kiyohiko Kawai ◽  
Sachiko Tojo ◽  
Tetsuro Majima
Keyword(s):  
Radical Cation ◽  
Transient Absorption ◽  
Hole Transfer ◽  
Kinetics Of

Efficient hole transfer from monolayer WS2 to ultrathin amorphous black phosphorus

2019 ◽  
Vol 4 (1) ◽  
pp. 236-242 ◽  
Author(s):  
Matthew Z. Bellus ◽  
Zhibin Yang ◽  
Peymon Zereshki ◽  
Jianhua Hao ◽  
Shu Ping Lau ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Transient Absorption ◽  
Black Phosphorus ◽  
Absorption Measurement ◽  
Two Dimensional ◽  
Hole Transfer ◽  
Ultrafast Charge Transfer

Transient absorption measurement reveals ultrafast charge transfer from crystalline to amorphous two-dimensional semiconductors.

scholarly journals PARP1 exhibits enhanced association and catalytic efficiency with γH2A.X-nucleosome

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Deepti Sharma ◽  
Louis De Falco ◽  
Sivaraman Padavattan ◽  
Chang Rao ◽  
Susana Geifman-Shochat ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mutational Analysis ◽  
Catalytic Efficiency ◽  
Double Strand Breaks ◽  
Genomic Integrity ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Nucleosome Core ◽  
Epigenetic Marker ◽  
Kinetics Of

AbstractThe poly(ADP-ribose) polymerase, PARP1, plays a key role in maintaining genomic integrity by detecting DNA damage and mediating repair. γH2A.X is the primary histone marker for DNA double-strand breaks and PARP1 localizes to H2A.X-enriched chromatin damage sites, but the basis for this association is not clear. We characterize the kinetics of PARP1 binding to a variety of nucleosomes harbouring DNA double-strand breaks, which reveal that PARP1 associates faster with (γ)H2A.X- versus H2A-nucleosomes, resulting in a higher affinity for the former, which is maximal for γH2A.X-nucleosome that is also the activator eliciting the greatest poly-ADP-ribosylation catalytic efficiency. The enhanced activities with γH2A.X-nucleosome coincide with increased accessibility of the DNA termini resulting from the H2A.X-Ser139 phosphorylation. Indeed, H2A- and (γ)H2A.X-nucleosomes have distinct stability characteristics, which are rationalized by mutational analysis and (γ)H2A.X-nucleosome core crystal structures. This suggests that the γH2A.X epigenetic marker directly facilitates DNA repair by stabilizing PARP1 association and promoting catalysis.

scholarly journals Design, Synthesis and Pharmacological Evaluation of Three Novel Dehydroabietyl Piperazine Dithiocarbamate Ruthenium (II) Polypyridyl Complexes as Potential Antitumor Agents: DNA Damage, Cell Cycle Arrest and Apoptosis Induction

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1453
Author(s):  
Haoran Wang ◽  
Jianhua Wei ◽  
Hong Jiang ◽  
Ye Zhang ◽  
Caina Jiang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Arrest ◽  
Antitumor Agents ◽  
Mechanistic Study ◽  
Ros Generation ◽  
Polypyridyl Complexes ◽  
Expression Levels ◽  
Cycle Arrest ◽  
Study Results

The use of cisplatin is severely limited by its toxic side-effects, which has spurred chemists to employ different strategies in the development of new metal-based anticancer agents. Here, three novel dehydroabietyl piperazine dithiocarbamate ruthenium (II) polypyridyl complexes (6a–6c) were synthesized as antitumor agents. Compounds 6a and 6c exhibited better in vitro antiproliferative activity against seven tumor cell lines than cisplatin, they displayed no evident resistance in the cisplatin-resistant cell line A549/DPP. Importantly, 6a effectively inhibited tumor growth in the T-24 xenograft mouse model in comparison with cisplatin. Gel electrophoresis assay indicated that DNA was the potential targets of 6a and 6c, and the upregulation of p-H2AX confirmed this result. Cell cycle arrest studies demonstrated that 6a and 6c arrested the cell cycle at G1 phase, accompanied by the upregulation of the expression levels of the antioncogene p27 and the down-regulation of the expression levels of cyclin E. In addition, 6a and 6c caused the apoptosis of tumor cells along with the upregulation of the expression of Bax, caspase-9, cytochrome c, intracellular Ca2+ release, reactive oxygen species (ROS) generation and the downregulation of Bcl-2. These mechanistic study results suggested that 6a and 6c exerted their antitumor activity by inducing DNA damage, and consequently causing G1 stage arrest and the induction of apoptosis.

scholarly journals Porous Carbon Architecture Assembled by Cross-Linked Carbon Leaves with Implanted Atomic Cobalt for High-Performance Li–S Batteries

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruirui Wang ◽  
Renbing Wu ◽  
Chaofan Ding ◽  
Ziliang Chen ◽  
Hongbin Xu ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Specific Capacity ◽  
Three Dimension ◽  
Zeolitic Imidazolate Framework ◽  
Shuttle Effect ◽  
Promising Solution ◽  
Fading Rate ◽  
Kinetics Of ◽  
Sulfur Cathodes

AbstractThe practical application of lithium–sulfur batteries is severely hampered by the poor conductivity, polysulfide shuttle effect and sluggish reaction kinetics of sulfur cathodes. Herein, a hierarchically porous three-dimension (3D) carbon architecture assembled by cross-linked carbon leaves with implanted atomic Co–N4 has been delicately developed as an advanced sulfur host through a SiO2-mediated zeolitic imidazolate framework-L (ZIF-L) strategy. The unique 3D architectures not only provide a highly conductive network for fast electron transfer and buffer the volume change upon lithiation–delithiation process but also endow rich interface with full exposure of Co–N4 active sites to boost the lithium polysulfides adsorption and conversion. Owing to the accelerated kinetics and suppressed shuttle effect, the as-prepared sulfur cathode exhibits a superior electrochemical performance with a high reversible specific capacity of 695 mAh g−1 at 5 C and a low capacity fading rate of 0.053% per cycle over 500 cycles at 1 C. This work may provide a promising solution for the design of an advanced sulfur-based cathode toward high-performance Li–S batteries.

Hollow structure engineering of FeCo alloy nanoparticles electrospun in nitrogen-doped carbon enables high performance flexible all-solid-state zinc–air batteries

2020 ◽  
Vol 4 (4) ◽  
pp. 1747-1753 ◽  
Author(s):  
Yuanyuan Ma ◽  
Wenjie Zang ◽  
Afriyanti Sumboja ◽  
Lu Mao ◽  
Ximeng Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Hollow Structure ◽  
Active Surface ◽  
Oxygen Electrode ◽  
Active Surface Area ◽  
Active Components ◽  
Nitrogen Doped Carbon ◽  
Structure Engineering ◽  
Kinetics Of

Hollow structuring of active components is an effective strategy to improve the kinetics of oxygen electrode catalysts, arising from the increased the active surface area, the defects on the exposed surface, and the accessible active sites.

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