Project description:From the results of gene expression analyses of HepG2 under the exposure of 2,3-Dimethoxy-1,4-naphthoquinone (DMNQ), N-nitrosodimethylamine (DMN), phenol and six heavy metals We showed that biological action of six heavy metals were clearly related to that of DMNQ and distinguishable from the other chemicals. These results suggest that oxidative stress is major apparent biological action of high dose heavy metals, supporting the previous reports. Experiment Overall Design: Using Affymetrix HG-Focus arrays, we compared the gene expression patterns of Hep G2 cells induced by six heavy metals (As, Cd, Ni, Sb, Hg or Cr) with that of DMNQ, DMN or phenol, and evaluated the toxicities of these heavy metals.
Project description:From the results of gene expression analyses of HepG2 under the exposure of 2,3-Dimethoxy-1,4-naphthoquinone (DMNQ), N-nitrosodimethylamine (DMN), phenol and six heavy metals We showed that biological action of six heavy metals were clearly related to that of DMNQ and distinguishable from the other chemicals. These results suggest that oxidative stress is major apparent biological action of high dose heavy metals, supporting the previous reports. Keywords: other
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:We hypothesize that microarray-based analysis of Lycopersicon esculentum is a sensitive tool for the early detection of potential toxicity of heavy metals, as well as an effective tool for identifying the heavy metal-specific genes. To test the hypothesis, the Agilent whole-genome cDNA microarrays were used to assess the effects of heavy metal on L. esculentum at relatively low concentrations (1/10 LC50 of heavy metals). Results showed that the characteristic gene expression profiles induced by Cd, Cr, Hg and Pb were not only distinct from the control but also distinct from one another, demonstrating the feasibility of discriminating between the effects of these four heavy metals present at relatively low concentrations. Moreover, heavy metal-specific genes were identified by microarray analysis. These findings support the above hypothesis.
Project description:Various chemicals, including pesticides, heavy metals, and metabolites of tobacco, have been detected in fetal environment. Fetuses are exposed to these chemicals at relatively low concentrations; however, their risk of developing neurological and behavioral disorders increases after birth. We aimed to evaluate the effects of five chemicals (diethylphosphate, cotinine, octachlorodipropyl ether, mercury, and selenium) detected in the serum of pregnant mothers on DNA methylation status during neural development using human neural stem cells.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.