title: Effect of melamine toxicity on Tetrahymena thermophila proliferation and metallothionein expression.
abstract: Melamine is a raw material in the chemical industry. Because of its high nitrogen content, melamine has been utilized by unscrupulous businessmen as a food additive to enhance the indices of protein content in food and feed testing. Tetrahymena has long been used as an excellent model organism in toxicological studies. The purpose of the present study was to determine the effect of melamine on Tetrahymena. In the present study, the effects of melamine on the proliferation and mating rate of Tetrahymena were examined by microscopic counting of the cell numbers. The comet assay and DAPI nuclear staining were performed to analyze the changes in the Tetrahymena genome. Flow cytometric analysis was conducted to detect apoptosis. Furthermore, RT-PCR was performed to determine the changes in the expression of the metallothionein gene in Tetrahymena that underwent stress treatment with varying concentrations of melamine. The results indicated that melamine affected the proliferation and sexual reproduction of Tetrahymena. High melamine concentrations damaged the Tetrahymena genome to a certain extent and induced apoptosis in the organism. Expression of the metallothionein gene was upregulated in Tetrahymena exposed to melamine stress to ameliorate melamine-induced damage. These results indicated that melamine displayed significant toxicity to Tetrahymena cells.
authors.affiliation: Key Laboratory of Biomedical Engineering & Technology of Shandong High School, Shandong Wanjie Medical College, Zibo 255213, China. Electronic address: wj_jclw@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Science, Shandong Normal University, Jinan 250014, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Science, Shandong Normal University, Jinan 250014, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Sports Science Research Center of Shandong Province, Jinan 250102, China.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Tian
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation; D004249:DNA Damage / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D008668:Metallothionein / Q000378:metabolism*; D012098:Reproduction / Q000187:drug effects; D016808:Tetrahymena thermophila / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D014227:Triazines / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D014227:Triazines; D008668:Metallothionein; C011907:melamine
keywords: Apoptosis; DNA damage; Melamine; Metallothionein; Tetrahymena