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We report here for the first time that germanium oxide (GeO(2)) blocks cell progression. GeO(2) is not genotoxic to Chinese hamster ovary (CHO) cells and has limited cytotoxicity. However, GeO(2) arrests cells at G2/M phase. The proportion of cells stopped at G2/M phase increased dose-dependently up to 5 mM GeO(2) when treated for 12 h, but decreased at(More)
Proliferating cell nuclear antigen (PCNA/cyclin) is a nuclear protein that can stimulate purified DNA polymerase delta in vitro, and its synthesis correlates with the proliferation rate of cells. We have attempted to determine whether synthesis of PCNA/cyclin in Chinese hamster ovary cells is necessary to regulate entry into S phase. We have measured(More)
To gain insight into factors associated with the excessive accumulation of beta-amyloid in the Alzheimer disease (AD) brain, the present studies were initiated to distinguish between a unique primary structure of the AD-specific amyloid precursor mRNA vis a vis other determinants that may affect amyloid levels. Previous molecular cloning experiments focused(More)
A proteolytic activity capable of cleaving the Ku86 subunit of Ku protein to two polypeptides, with molecular masses of 69 and 17 kDa in vitro, is present in a human diploid fibroblast (HDF) cell line. The activity is elevated in late-passaged and senescent cells, and the cleaved 69-kDa product seems able to form complex with Ku70 to bind DNA ends. However,(More)
The Ku protein is an essential protein for DNA double-strand-break repair by the pathway of nonhomologous DNA end-joining (NHEJ). A previous study showed that Ku bound to one DNA molecule could transfer directly to another DNA molecule without being released into the solution first. Direct transfer requires the two DNA molecules having homologous cohesive(More)
Since the detailed molecular events leading to the formation of amyloid-containing senile plaques of the Alzheimer's disease (AD) brain are incompletely understood, the present studies were undertaken to address this issue using a combination of molecular and cytochemical approaches. Amyloid precursor protein riboprobes containing the A4 (beta-amyloid)(More)
A human factor IX cDNA clone isolated from a liver cDNA library constructed in phage lambda gt11 vector was shown to express factor IX protein in Escherichia coli. A factor IX immunospecific protein of 46.8 kDa was expressed, but was not a beta-galactosidase-factor IX fusion protein. Expression was seen when the factor IX cDNA was cloned into two different(More)
Pamamycin was previously identified as a stimulator of aerial mycelium formation in Streptomyces alboniger and as a new antibiotic. Studies in Staphylococcus aureus grown in brain heart infusion broth showed that this antibiotic was bacteriostatic at 0.1 to 0.3 U/ml and bactericidal at 0.5 U/ml or higher. At concentrations which inhibited growth ca. 40%,(More)