High concentration of extracellular nucleotides suppresses cell growth via delayed cell cycle progression in cancer and noncancer cell lines.

Tumor necrosis frequently occurs in malignant tumors, showing rapid growth and invasion. This phenomenon is generally regarded as simple ischemic necrosis due to insufficient tumor vessels and blood supply. However, the necrotic tissue contains high amount of nuclear substances, DNA, and nucleoproteins that may affect the surrounding tumor cells by promoting or suppressing the tumor cell growth .

Photo-switching of blunt-end stacking between DNA strands immobilized on gold nanoparticles.

End-to-end intermolecular interaction between double-stranded DNAs grafted onto individual nanoparticles is regulated by terminal base pairing/unpairing triggered by the photo-isomerization of an azobenzene moiety inserted in the vicinity of the DNA terminal. This is the first example of highly reversible control of blunt-end stacking under both isothermal and isoionic-strength conditions.

Terminal-Specific Interaction between Double-Stranded DNA Layers: Colloidal Dispersion Behavior and Surface Force.

Double-stranded DNA-grafted nanoparticles (dsDNA-NPs) exhibit a unique dispersion behavior under high-salt conditions depending on the pairing status of their outermost base pairs (pairing or unpairing). The dsDNA-NPs having complementary (i.e.

Geometric effect on the photocrosslinking reaction between 3-cyanovinylcarbazole nucleoside and pyrimidine base in DNA/RNA heteroduplex.

To clarify the geometric effect of the ultra-fast photocrosslinking reaction of photoreactive oligodeoxyribonucleotide containing 3-cyanovinylcarbazole nucleoside ((CNV)K) on uridine in complementary RNA strands, pseudouridine (Ψ), which is an isomer of uridine with a C5-C1' glycosidic bond, was introduced to the photocrosslink site of (CNV)K in complementary RNA instead of U. The photoreactivity of (CNV)K toward Ψ was two-fold lower than that of U, suggesting that the geometry between the vinyl moiety on (CNV)K and the reactive double bond in the pyrimidine base has a large affect on the photoreactivity of (CNV)K. Contrary to the case of U, the reactivity of the (CNV)K toward Ψ was decreased by the decrease of reaction temperature below the Tm of heteroduplex, suggesting that the flexible structure of the duplex is advantageous for the photocrosslinking reaction with Ψ, whose reactive double bond possesses unfavorable geometry for the photocrosslinking reaction with (CNV)K.