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Because many anticancer drugs interact with DNA, the determination of their association constants to DNA is essential for quantifying their mechanisms of action. The interactions between a new ruthenium-derived compound [ruthenium(phenanthroline)(κ-C,N-(2-phenyl-pyridine)(NCMe)(2)]PF(6), called RDC11] and DNA are studied using different techniques. Fluorescent experiments are used to determine the association and dissociation constants under different salt concentrations. The binding is shown to be reversible and noncovalent. The association constants vary from 1.5 × 10(6) M(-1) to 2.9 × 10(3) M(-1) when increasing the sodium concentration from 0.1 to 200 mM. Single-molecule stretching methods are used to study the interaction of RDC with longer DNA strands (8.6 kbp home-built dimer of pBR322). The affinities of RDC with DNA under different loads are obtained using McGhee and von Hippel analysis. The affinity constant and thermodynamic parameters are in good agreement with the values found in the literature and lead to the conclusion that this molecule intercalates dsDNA.
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http://dx.doi.org/10.1021/jp1044783 | DOI Listing |
Nat Commun
September 2025
Plant Ecology, University of Bayreuth, Bayreuth, Germany.
The unique biodiversity and vast carbon stocks of the Amazon rainforests are essential to the Earth System but are threatened by future water balance changes. Empirical evidence suggests that species and trait diversity may mediate forest drought responses, yet little evidence exists for tropical forest responses. In this simulation study, we identify key axes of trait variation and quantify the extent to which functional trait diversity increases tropical forests' drought resistance.
View Article and Find Full Text PDFPlant Cell Physiol
September 2025
Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
Phycobilisome (PBS) is a water-soluble light-harvesting supercomplex found in cyanobacteria, glaucophytes, and rhodophytes. PBS interacts with photosynthetic reaction centers, specifically photosystems II and I (PSII and PSI), embedded in the thylakoid membrane. It is widely accepted that PBS predominantly associates with PSII, which functions as the initial complex in the linear electron transport chain.
View Article and Find Full Text PDFInt J Sports Physiol Perform
September 2025
Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA.
Purpose: To assess the association between skeletal-muscle endurance performance and mitochondrial oxidative capacity of the hamstrings as respectively measured by biomechanical and physiological standards.
Methods: Nineteen (12 men and 7 women) healthy, young, recreationally active participants enrolled in our study. Participant characteristics comprised a mean and SD age of 21.
Proc Biol Sci
September 2025
Department of Biology, Evolutionary Ecology and Infection Biology, Lund University, SE-223 62, Lund, Sweden.
Incubation temperature affects both growth and energy metabolism in birds after hatching. Changes in cellular mechanisms, including mitochondrial function, are a likely but unexplored explanation for these effects. To test whether temperature-dependent changes to mitochondria may link embryonic development to the post-natal phenotype, we incubated Japanese quail eggs at constant low (36.
View Article and Find Full Text PDFJ Phys Chem B
September 2025
Department of Physics, Division of Nano and Biophysics, Chalmers University of Technology, Fysikgränd 3, Göteborg 41296, Sweden.
The detection of biological nanoparticles (NPs), such as viruses and extracellular vesicles (EVs), plays a critical role in medical diagnostics. However, these particles are optically faint, making microscopic detection in complex solutions challenging. Recent advancements have demonstrated that distinguishing between metallic and dielectric signals with twilight off-axis holographic microscopy makes it possible to differentiate between metal and biological NPs and to quantify complexes formed from metal and biological NPs binding together.
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