中文关键词
四环素四环素抗性基因弗氏志贺氏菌抗性表达水平基因丰度 | 英文关键词tetracyclinetetracycline resistance geneShigella flexneriexpression levelgene abundance |
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| 中文摘要 |
| 四环素（TC）抗生素在不同环境介质中已被广泛检出，为研究其对四环素抗性基因（TC-ARGs）丰度变化及表达水平的影响过程，以从活性污泥中筛选和纯化分离获得的弗氏志贺氏菌（Shigella flexneri）为研究对象，考察了不同浓度TC对其生长过程的作用影响，采用荧光定量PCR和逆转录PCR方法定量检测了不同抗性机制TC-ARGs，包括tetC、tetO和tetX基因的丰度变化及表达水平，并探讨了TC浓度与TC-ARGs丰度及其表达水平之间的相关关系.结果表明，在培养周期内（24 h），TC胁迫对Shigella flexneri细菌的生长具有抑制作用，细菌细胞浓度增长速率随TC暴露浓度的升高而降低，但对TC-ARGs丰度变化影响较小.TC胁迫能够促进Shigella flexneri细菌TC-ARGs的转录表达，tetC、tetO和tetX基因表达水平在整个培养周期内均先升高后降低.由相关性分析可知，TC浓度与TC-ARGs丰度及其表达水平之间相关关系不显著，但tetC和tetO基因丰度与其转录表达水平之间存在显著的正相关关系，表明其基因丰度一定程度上可用来衡量和评价其抗性表达水平. |
| 英文摘要 |
| The tetracycline (TC) antibiotic has been widely found in different environmental matrices. The tetracycline resistant bacterium (TRB) of Shigella flexneri was screened and purified from activated sludge, and was then used to study the impact of TC stress on the gene abundances and expression levels of TC resistance genes (TC-ARGs), including tetC, tetO, and tetX, which were respectively quantified by quantitative PCR and reverse transcriptional PCR. Correlations between the TC concentration and gene abundances of TC-ARGs and their expression levels were discussed. The results showed that TC stress had an inhibiting effect on the growth of Shigella flexneri during the entire culture cycle (24 h) and that the growth rate of the bacterial concentration decreased with increasing TC concentration. However, less impact on the gene abundance of TC-ARGs was found. TC stress could promote the expression of TC-ARGs in Shigella flexneri, and the expression levels of tetC, tetO, and tetX genes first increased and then decreased. The correlation results indicated that no significant correlation was observed between the TC concentration and gene abundances of TC-ARGs and their expression levels. Nevertheless, the gene abundances of tetC and tetO were significantly correlated with their expression levels, thus indicating that they can be used to evaluate and assess expression levels to a certain extent. |
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