Looking at Hg distribution by nano-X-ray fluorescence to elucidate the role of a two-component sensing system and a metal efflux system in b

Methylmercury (MeHg) is a strong neurotoxin and is mainly produced by sulfate-reducing bacteria (SRB) in anoxic environments. However, the mechanisms of Hg methylation are still poorly understood. We study the model SRB strain Pseudodesulfovibrio hydrargyri BerOc1 and we have generated BerOc1 mutants impaired with a metal efflux system and with a two-component sensing system involved in Hg regulation, and probably Hg sequestration. These mutants showed specific phenotypes in Hg methylation. Our objective is to clarify the role of these genes in Hg distribution at the cell level. For that, we will image single cells from wild type and mutants by nano X-ray fluorescence (nano-XRF)

甲基汞（Methylmercury，MeHg）是一种强神经毒素，主要由缺氧环境中的硫酸盐还原菌（sulfate-reducing bacteria，SRB）产生。然而，汞甲基化机制仍知之甚少。我们以SRB模式菌株Pseudodesulfovibrio hydrargyri BerOc1为研究对象，构建了BerOc1突变株——这些突变株的金属外排系统（metal efflux system）及参与汞调控（可能还涉及汞螯合，Hg sequestration）的双组分传感系统（two-component sensing system）均受损。这些突变株在汞甲基化方面表现出特定表型。我们的目标是阐明这些基因在细胞水平汞分布中的作用。为此，我们将通过纳米X射线荧光（nano-XRF）技术对野生型及突变株的单细胞进行成像分析。