中文摘要：

通过对floR基因序列的分析，将扩增的包含floR基因上游调控序列及下游终止序列的约1550bp DNA片段克隆到pGEM-Teasy载体上，成功构建了pGEM—floR质粒，将质粒转入JM109中，药物敏感性试验显示构建的pGEM-floR／JM109基因工程菌对氯霉素和氟苯尼考高度耐药，对四环素和庆大霉素敏感。本试验成功构建了一个基因背景清楚且对氟苯尼考耐药的细菌模型，排除了细菌中其他氟苯尼考耐药基因或泵出蛋白对floR基因贡献细菌耐药表型及进一步试验的影响。分别提取CVM1841、pGEM-floR／JM109、pGEM／JM109和JM109膜蛋白，运用实验室制备的鼠抗GST-FloR1抗体进行免疫印迹反应，蛋白定位显示FloR蛋白位于细菌的细胞膜上。本试验结果证实floR基因编码的蛋白位于细胞膜，并贡献细菌对氯霉素和氟苯尼考的交叉耐药性。

英文摘要：

A positive plasmid that comprises the entire floR ORF and possible regulatory site was obtained and named plasmid pGEM-floR. The recombinant plasmids were successfully transformed into E. coli JM109. A significant resistance to florfenicol and chloramphenicol was found in this strain which was susceptive to tetracycline and gentamicin. Location of FloR protein was confirmed by immunoblotting that using the membrane fraction of florfenicol-resistant E. coli strains （pGEM-floR/JM109 and CVM1841 ） and the florfenicol-sensitive （negative-control） strains （pGEM-T/JM109） with the GST-FloR1 mouse antisera. The Western blot results showed that the antibody had specific binding to the FloR protein and confirmed that FloR protein was a membrane protein in florfenicol-resistant bacteria. The research shows that protein encoded by floR gene locates at the cellular membrane and confers cross-resistant to flofenicol and chloramphenicol.