Bacterial multi-resistance mechanisms: multi-metal(loid) sensitivity-tolerance and transformations

我的NSERC资助的研究计划植根于了解细菌的毒素抗性机制。我的团队提出了这样一个问题：“是什么生物化学和生理学允许细菌处理特定化学组中的各种杀菌剂，而不是特定的化合物？”在这一框架下，本应用程序探索细菌中多金属抗性/耐受性的遗传和生化机制，与使用细菌生物修复污染环境中的金属和金属污染物以及了解用作抗菌剂的金属有关。我们已经在生化机制方面取得了一些发现，并确定了负责对有毒金属敏感/耐受的基因。这项工作提供了证据，证明并不是所有的金属都会产生文献中错误假设的相同的杀死机制。为了跟进这些发现，这一赠款周期的方向是更深入地探索对银、铜和镓的敏感性和耐受性的共同基因，这些基因被批准为金属抗菌剂。我们发现，在这些不同的金属之间，只有一小部分基因在敏感性或耐受性方面存在重叠。我们将评估这些基因对其他14种有毒金属的突变体，看看这些基因的反应有多普遍。此外，我们的目标是使用我们开发的化学基因组筛选来评估细菌对类金属氧离子的反应，特别是：硒、碲、砷和锑。到目前为止，很少或根本没有对暴露于这些类金属的细菌进行广泛的系统研究(代谢组学、基因组学、蛋白质组学)，但这些都是正在演变或确定的环境污染物，以及变得更具经济相关性。从我对金属离子污染修复的兴趣来看，我们发现了能够生物吸附金属的菌株；但除此之外，我们观察到它们将金属离子转化为纳米材料。这很快演变成了一个研究硒和碲纳米材料的细菌生物合成的项目。展望未来，目标将是系统地探索微生物的生理状态及其对生物纳米材料生产的影响及其特征。我想了解它们生物合成的生物化学。一个令人兴奋的结果将是生物转化修复战略，它不仅将从废物/矿山/尾矿水中去除金属污染物，还将同时生产用于光伏和电子产品的增值有用材料。这些研究的广泛范围是提供生化和分子微生物学，了解细菌在不同有毒金属离子存在下受到挑战时的反应，以及如何在没有特定金属抗性基因决定因素的情况下实现耐受性。我们想要回答的根本问题是，在基因组和生化水平上，多金属的敏感性和耐受性是什么样子的？

My NSERC funded research program is rooted in understanding toxin resistance mechanisms in bacteria. My group asks the question: "What biochemistry and physiology allow bacteria to deal with a variety of biocide agents within a specific chemical group, rather than a specific compound?" Under this envelope, this application explores the genetic and biochemical mechanisms of multi-metal resistance/tolerance in bacteria with a connection to using bacteria in bioremediation of metals and metalloid pollutants from contaminated environments as well as understanding metals used as antimicrobials. We have made a number of discoveries around the biochemical mechanisms and identified genes responsible for sensitivity/tolerance towards toxic metals. This work provided evidence that not all metals give rise to the same killing mechanism which has been incorrectly assumed in the literature. To follow up on these discoveries, this grant cycle's directions are to explore deeper the shared genes of sensitivity and tolerance towards silver, copper and gallium, which are approved as metal-based antimicrobials. We discovered there was only a small set of genes that overlapped between these different metals for sensitivity or tolerance. We will evaluate the mutants of these genes to 14 other toxic metals to see how universal these genes responses are. Additionally, we aim to use our developed chemical genomic screen to evaluate bacterial response to oxyanions of metalloids, particularly: selenium, tellurium, arsenic and antimonite. Little to no broad system studies (metabolomics, genomics, proteomics) have been performed on bacteria exposed to these metalloids to date, yet these are evolving or established environmental pollutants as well as becoming more economically relevant. From my interest in metal ion pollution remediation, we discovered strains capable of biosorption of the metal; but beyond this, we observed they converted the metal ion into nanomaterials. This has quickly evolved into a project studying bacterial biosynthesis of selenium and tellurium nanomaterials. Moving forward, the aim will be to systematically explore microbial physiological states and their influence on biogenic nanomaterial production and their characteristics. I want to understand the biochemistry of their biosynthesis. An exciting outcome would be bioconversion remediation strategies that will not only remove the metal pollutant from waste/mine/tailings water but produce value-added useful materials for photovoltaics and electronics at the same time. The broad scope of these studies is to provide a biochemical and molecular microbiology understanding of the response of a bacterial to being challenged to grow in the presence of different toxic metal ions and how tolerance is achieved without specific metal resistance gene determinants. The fundamental question we want to answer - What does multi-metal sensitivity and tolerance look like at the genomic and biochemical level?