Two Paths to Oxidative C-H Amination Under Basic Conditions: A Theoretical Case Study Reveals Hidden Opportunities Provided by Electron Upconversion.

Traditionally, cross-dehydrogenative coupling (CDC) leads to C-N bond formation under basic and oxidative conditions and is proposed to proceed via a two-electron bond formation mediated by carbenium ions. However, the formation of such high-energy intermediates is only possible in the presence of strong oxidants, which may lead to undesired side reactions and poor functional group tolerance. In this work we explore if oxidation under basic conditions allows the formation of three-electron bonds (resulting in "upconverted" highly-reducing radical-anions).

Mapping of functional domains within the Saccharomyces cerevisiae type 1 killer preprotoxin.

Strains of Saccharomyces cerevisiae harboring M1-dsRNA, the determinant of type 1 killer and immunity phenotypes, secrete a dimeric 19-kd toxin that kills sensitive yeast cells by the production of cation-permeable pores in the cytoplasmic membrane. The preprotoxin, an intracellular precursor to toxin, has the domain sequence delta-alpha-gamma-beta where alpha and beta are the 9.5-and 9.

Role of polyamines in HeLa cell proliferation.

HeLa cells were synchronized for S phase DNA synthesis by the double thymidine block procedure and simultaneously depleted of putrescine and spermidine with the irreversible inhibitor of ornithine decarboxylase, alpha-difluoromethyl ornithine. S phase DNA synthesis was inhibited and cell proliferation was prevented in the cells in which polyamines were depleted by the inhibitor of ornithine decarboxylase. Nuclei prepared from synchronized, polyamine-depleted cells were almost totally inactivated for in vitro DNA synthesis.