摘要
本文在荧光定量PCR优化的基础上,利用该技术考察了不同浓度的重金属镉和铜对嗜热四膜虫金属硫蛋白基因(MTT1)诱导表达的变化规律。结果表明MTT1基因的表达对镉离子的诱导更灵敏,且在一定阈值浓度(≤35.2μmol/L)范围内,镉离子浓度升高会增加MTT1基因表达量,超过该阈值后表达量迅速下降;镉与铜同时诱导时MTT1基因的表达情况与镉单独诱导的类似,但阈值浓度减小为22μmol/L,表明二者的联合毒性为协同作用。镉离子浓度低于22μmol/L时,与铜离子的共同作用会大大增加MTT1基因的表达量,从而增强了四膜虫的解毒能力。
Heavy metal pollution has become the major concern of many countries, and the key to control the matter calls for good model organisms as early-warning indicators, effective target genes as molecular markers, and a sensitive method studying differential expressions of the genes. To study the potential molecular mechanisms of cadmium and copper combined toxicity, the unicellular protozoa Tetrahymena thermophila was chosen for its fast growth and sensitivity to pollutants in water ecosystem, and a method of real-time fluorescent quantitative PCR （Q-PCR） was applied which is effective, accurate and has been widely used in molecular field. In this article, the Q-PCR method was optimized, on the basis of which tests were designed to study the relative expression of metallothionein gene （ MTT1 ） in T. thermophila treated with different concentrations of heavy metals cadmium and copper. The results suggested that： MTT1 gene was more sensitive to cadmium induction compared to copper, and in a certain threshold scale （435.2 μmol/L）, raising the cadmium concentrations increased the MTT1 expression level, but made it decreased while beyond the threshold; the expression rule of MTT1 induced by both cadmium and copper was similar to that treated with cadmium only, but then the threshold down to 22 μmol/L, indicating that combined toxicity of cadmium and copper in T. thermophila were synergism. When treating concentration was lower than 22 μmol/L, cadmium cooperated with 244 μmol/L copper greatly increased the expression level of MTT1, hence enhancing the detoxification ability of Tetrahymena [ Acta Zoologica Sinica 51 （6）： 1115-1121, 2005].
出处
《动物学报》
SCIE
CAS
CSCD
北大核心
2005年第6期1115-1121,共7页
ACTA ZOOLOGICA SINICA
基金
淡水生态与生物技术国家重点实验室开放课题资助~~
关键词
嗜热四膜虫
金属硫蛋白基因
实时荧光定量PCR
Tetrahymena thermophila, Metallothionein gene, The real-time fluorescent quantitative PCR
