We used retrovirus insertion-mediated random mutagenesis and tumor necrosis factor (TNF) selection to generate TNF-resistant lines from L929 cells. The metaxin gene, which encodes a protein located on the outer membrane of mitochondria, was identified to be the gene disrupted in one of the resistant lines. The requirement of metaxin in TNF-induced cell death of L929 was confirmed by the restora...

The existence of reliable mtDNA reference sequences for each species is of great relevance in a variety of fields, from phylogenetic and population genetics studies to pathogenetic determination of mtDNA variants in humans or in animal models of mtDNA-linked diseases. We present compelling evidence for the existence of sequencing errors on the current mouse mtDNA reference sequence. This includ...

The messenger RNAs of many proto-oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU-rich elements (AREs) located in their 3' untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for ARE-containing RNA sequences in vitro which correlate with their in vivo decay rates, thereby imp...

Nonexcitable cell types, fibroblasts of heart muscle or astrocytes, are well known for their spontaneous Ca(2+) oscillations. On the other hand, murine fibroblast (L929) cells are known to be deficient in cell-cell adhesive proteins and therefore lack gap junctions for cellular communication. However, these cells exhibit a unique property of collectively synchronized and spontaneous oscillation...

OBJECTIVES Endodontically treated teeth with insufficient tooth structure are often restored with esthetic restorations. This study evaluated the cytotoxicity and biological effects of yttria partially stabilized zirconia (Y-TZP) blocks in combination with several dental cements. MATERIALS AND METHODS Pairs of zirconia cylinders with medium alone or cemented with three types of dental cement ...

BACKGROUND Rickettsia raoultii is a novel Rickettsia species recently isolated from Dermacentor ticks and classified within the spotted fever group (SFG). The inability of R. raoultii to spread within L929 cells suggests that this bacterium is unable to polymerize host cell actin, a property exhibited by all SFG rickettsiae except R. peacocki. This result led us to investigate if RickA, the pro...

Tumor necrosis factor (TNF) signals cell death and simultaneously induces generation of ceramide. To evaluate the contribution of ceramide to TNF-dependent cell death, we generated clones of the TNF-sensitive cell line L929 that constitutively overexpress human acid ceramidase (AC). Ceramidase, in concert with sphingosine kinase, metabolizes ceramide to sphingosine-1-phosphate (SPP), an inducer...

We have previously shown that lactoperoxidase (LPO) covalently coupled to polystyrene tissue culture flasks can be used to radioiodinate monolayer cell proteins that come into intimate contact with the LPO-polystyrene surface. These studies have now been extended to include a detailed examination of the class of iodinated polypeptides migrating with apparent molecular weights of 50,000 and 55,0...

This study aimed to evaluate the cytotoxicity of a crude extract of Piper cubeba against normal and breast cancer cell lines. To prepare the extract, P. cubeba seeds were ground, soaked in methanol and dichloromethane and isolated by column chromatography. Fractions were tested for cytotoxicity effects on normal fibroblast (L929), normal breast (MCF-12A) and breast cancer cell lines (MCF-7, MDA...

OBJECTIVE The aim of this study was to investigate the cytotoxicity of two different bioactive root canal sealers: one based on mineral trioxide aggregate, MTA Fillapex (Angelus, Solucoes Odontologicas, Londrina, PR, Brazil), and the other based on bioceramics, Endosequence BC Sealer (Brasseler, Savannah, Georgia, USA), in culture of mouse L929 fibroblasts. MATERIALS AND METHODS Mouse fibrobl...