趋磁细菌及其生物矿化的研究具有重要的理论价值和广泛的应用前景，但以往的工作多集中于磁小体岛内基因，对岛外基因的研究较少。.本实验室最近完成了磁螺菌MSR-1的全基因组和转录组的分析，发现在磁小体生物合成的时期，与反硝化作用相关的一些基因的转录水平增加。特别是硝酸还原酶(nap)操纵子、napC同源的MGMSRv2_2833基因、参与亚硝酸还原的nirT基因等显著上调。.本研究拟以磁螺菌(MSR-1)为材料，采用EMSA、CHIP、DNA Printing等方法，探讨该菌两个与FNR同源的氧调节蛋白对nap操纵子的调控机制；通过同源双交换，构建缺失突变株，分析调节效果，以及主要的nap基因与nirT、MGMSRv2_2833等的功能，明确这些基因的特征及其对细胞生物矿化和反硝化作用的影响。研究结果，不仅可揭示趋磁细菌反硝化过程的特异性, 同时可阐明nap操纵子及其调控与磁小体合成的关系。

Magnetotactic bacteria are very important model organisms for bacterial biomineralization and appealed great interests for both research and application. Until now, the biosynthetic mechanism of magntosomes is still unknown. In past decades, researchers have focused most of their attention on genes in magnetosome islands. However, genes outside the island also play key roles during biomineralization..Recently, the complete genomic sequence and four transcriptomes of Magnetospirillum gryphiswaldense MSR-1 were analyzed by our group. Surprisingly, when magnetosome appeared in MSR-1 cells, the expression of some denitrification genes was obviously up regulated, such as periplasmic nitrate reductase (nap) operon, a napC homologous gene (MGMSRv2_2833), and a gene involved nitrite reduction (nirT)..In this work, the mechanism of FNR-mediated oxygen-responsive regulation of the nap operon would be investigated by Electrophoretic Mobility Shift Assay, Chromatin immunoprecipitation, and DNA footprinting, as we found two fnr homologous genes (MGMSRv2_2046 and MGMSRv2_2946) in MSR-1 genome and also their binding site at the upstream of nap operon. The effects of FNR regulation would be estimated by constructing mutant strains by double cross-over gene replacement. The functions of key genes in denitrification pathway (napF, napA, napC, nirT, MGMSRv2_2833) would be analyzed by the same mutation method, respectively. The results would not only show the differences of denitrification pathways between magnetotactic bacteria and non-magnetotactic bacteria, but also relationship between nap operon and magnetosome biosynthesis.