Development and application of a stable HeLa cell line capable of site-specific transgenesis using the Cre-lox system: establishment and application of a stable TNFRI knockdown cell line to cytotoxicity assay.

Mammalian cell models for gene knock-out/knock-in experiments are important for functional analysis of genes and have a potential of useful tool for toxicological studies. However, uncontrolled insertion of transgenes has raised significant concerns over unwanted side effects. To address this issue, we established a stable HeLa55 cell line capable of site-specific transgenesis by means of Cre-mediated cassette exchange at a site on the long arm of human chromosome 9 containing no constitutive transcripts.

Application of RNAi inducible TNFRI knockdown cells to the analysis of TNFalpha-induced cytotoxicity.

RNA interference (RNAi) has become a popular tool for downregulating in many species including mammalian cells. Therefore, suppression of target genes in mammalian cultured cells using RNAi may represent an ideal alternative to knockout studies for understanding the molecular mechanisms of chemical toxicity. Here, we assessed the potential of RNAi mediated gene knockdown in HeLa and HepG2 cells to cytotoxicity studies.

Influence of dispersants on bioconcentration factors of seven organic compounds with different lipophilicities and structures.

Seven compounds with different lipophilicities and structures--1,3,5-trichlorobenzene, pentachlorobenzene, acenaphthylene, 1,4-dimethyl-2-(1-methylphenyl)benzene, 4-ethylbiphenyl, 4,4'-dibromobiphenyl, and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane--were subjected to bioconcentration tests in carp at concentrations below the water solubilities of the compounds in the presence or absence of a dispersant (either an organic solvent or a surfactant). The bioconcentration factors (BCFs) of the compounds were on the order of 10(2)-10(4). The BCF values remained in the range of 15-49% for all the compounds, whether or not a dispersant was present, i.

Unique bioconcentration characteristics of new aryl fluoroalkyl ethers in common carp (Cyprinus carpio).

The bioconcentration factors (BCFs) of seven new aryl fluoroalkyl ethers--four bis-4-tetrafluoroethoxyphenyl-type (bis-type) compounds and three mono-4-tetrafluoroethoxyphenyl-type (mono-type) compounds--were obtained by bioconcentration tests using common carp. The BCFs of 4 of the 7 ethers were higher than 5000, indicating their high bioconcentration potential. The bioconcentration characteristics of the bis-type compounds were different from those of the mono-type compounds and non-fluoro diphenylmethanes with a similar skeleton structure to the bis-type compounds, in taking longer to reach a plateau and having a slower elimination rate and in their distribution patterns in the fish body.