title: Gene expression analysis and classification of mode of toxicity of polycyclic aromatic hydrocarbons (PAHs) in Escherichia coli.
abstract: Escherichia coli is known to respond to certain toxic chemicals through an increased expression of various stress genes. In this study, therefore, the expression of recA, katG, fabA and grpE genes was used as a representative for DNA, oxidative, membrane and protein damage, respectively, after E. coli was exposed to different polycyclic aromatic hydrocarbons (PAHs), i.e., phenanthrene, naphthalene and benzo[a]pyrene. To accomplish this, the expression levels of these four genes were quantified using a real-time RT-PCR analysis when E. coli cultures were under stressful conditions, such as those caused by an exposure to mitomycin C, hydrogen peroxide and phenol. It was found that the primary toxic effect of each chemical is clearly seen when the expression levels of the different genes are compared. Tests with the PAHs showed naphthalene and benzo[a]pyrene to be genotoxic, while phenanthrene had no clear effect on the expression of any of these genes. Based on these results, the effects due to these toxic chemicals and the extent of each stress can be evaluated with ease using the expression levels of different stress responsive genes.
authors.affiliation: College of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-gu, Seoul 136-701, South Korea.
authors.forename: Yeon Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Jiho
authors.initials: J
authors.lastname: Min
authors.forename: Han Na
authors.initials: HN
authors.lastname: Hong
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Kyeong Seo
authors.initials: KS
authors.lastname: Park
authors.forename: Man Bock
authors.initials: MB
authors.lastname: Gu
mesh_terms: D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D005798:Genes, Bacterial / Q000187:drug effects*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons