Spectrophotometric and nucleic acid-binding properties of halloysite clay nanotubes and kaolinite.

Halloysite particles (HNTs) are naturally occurring aluminosilicate nanotubes of low toxicity that have shown great promise for drug and biomolecule delivery into human and animal cells. Kaolinite particles retain the same layered structure as HNT, but do not form nanotubes. In this study, the spectrophotometric and sedimentation properties of the two clays in aqueous solutions and their abilities to associate with both small and large nucleic acids have been investigated.

pH-dependent sedimentation of DNA in the presence of divalent, but not monovalent, metal ions.

Precipitation of DNA is performed frequently in molecular biology laboratories for the purpose of purification and concentration of samples and also for transfer of DNA into cells. Metal ions are used to facilitate these processes, though their precise functions are not well characterized. In the current study we have investigated the precipitation of double-stranded DNA by group 1 and group 2 metal ions.

Quantitative assessment of changes in cell growth, size and morphology during telomere-initiated cellular senescence in Saccharomyces cerevisiae.

Telomerase-deficient cells of the budding yeast S. cerevisiae experience progressive telomere shortening and undergo senescence in a manner similar to that seen in cultured human fibroblasts. The cells exhibit a DNA damage checkpoint-like stress response, undergo changes in size and morphology, and eventually stop dividing.