CAREER: Career Development in the Emerging Field of Geomycology: Research and Education in Metal Biomineralization by Fungi

虽然许多金属是生命必不可少的微量营养物质，但在高浓度时，这些金属可能是有毒的，有时甚至是致命的。在废弃煤矿的酸性矿井水中，金属锰(Mn)的浓度可能比被认为是神经疾病健康风险的水平高出两个数量级。我们最近发现，在酸性矿山废水(AMD)环境中，锰的氧化和随后的固定化是由丰富的真菌群落介导的，该群落能将锰(II)完全和快速地氧化成锰(III/IV)氧化物。尽管真菌介导的过程被普遍观察到，其对地质过程的影响是毋庸置疑的，但关于参与金属生物地球化学循环的真菌种类、所采用的机制及其对土壤和沉积物的矿物学框架和反应性的影响，人们知之甚少。这份职业提案提出了一项综合教育和研究计划，以探索并最终确定真菌在地表环境，特别是受酸性矿井水影响的环境中氧化锰(II)的重要性。这项研究将在一个关于真菌多样性的本科项目和一篇研究生论文的范围内进行，该论文是关于关键的锰(II)氧化真菌分离株对锰(II)氧化和生物矿化的酶、生理和地球化学控制。其具体目标是确定(1)AMD系统中锰(II)氧化真菌的系统发育和生态多样性，(2)真菌介导的(A)生物锰(II)氧化途径，(3)生物钟对锰(II)氧化的作用，以及(4)锰(II)氧化速率和固相。这项研究将涉及结合分子生物学、酶和化学分析、显微镜和复杂的显微光谱技术的多学科方法，以探索分子和整体尺度上的微生物-金属-矿物相互作用。这份职业建议书中概述的研究将填补我们对锰循环的生物和地球化学控制知识的主要空白？对改善就地生物修复(例如AMD治疗)、刺激初级生产力和预测污染物在环境中的去向和迁移至关重要的信息。更广泛的影响：在大多数情况下，将抽象的化学和生物概念应用到现实生活中可以促进学生的兴趣和学习。AMD造成的视觉上引人注目和令人不安的破坏是一个理想的环境框架，可以教育学生了解支配自然世界健康的物理、微生物和化学过程的复杂性。这项提议的主要教育宣传部分将是为非正式和正式教育工作者创建和指导为期五天的AMD微生物学专业发展年度讲习班。该研讨会由哈佛大学微生物科学倡议和詹宁斯环境教育中心(JEEC)联合主办，题为？生活在酸中：创造和修复酸性矿山废水的微生物？并将侧重于AMD生态系统的生物地球化学和微生物生态学，包括讲座、实验室和实地练习以及课程开发论坛。这个工作坊将为寻求与微生物、环境质量和生物修复的前沿概念的实践科学教学的教育者提供一个独特的体验式学习机会。我们拟议的研究的新发现将直接纳入研讨会，并提供信息，包括高分辨率图像，供JEEC永久公开展示。这个工作坊将作为一个渠道，教育从农村到城市的广泛社会经济多样性的学生，并将我们对环境微生物学和生物修复的理解的进步引导到课堂和普通公众中。

While many metals are essential trace nutrients for life, at high concentrations these same metals can be toxic and at times fatal. Within acidic mine waters from abandoned coal mines, concentrations of the metal manganese (Mn) can be two orders of magnitude higher than levels considered a health risk for neurological disorders. We have recently found that oxidation and subsequent immobilization of Mn in acid mine drainage (AMD) environments is mediated by an abundant fungal community that completely and rapidly oxidizes Mn(II) to Mn(III/IV) oxides. Although fungal mediated processes are universally observed and their impact on geological processes indisputable, little is known about the fungal species involved in the biogeochemical cycles of metals, the mechanisms that are employed, and their impact on the mineralogical framework and reactivity of soils and sediments. This CAREER proposal presents an integrated education and research plan to explore and ultimately define the importance of fungi in the oxidation of Mn(II) within surface environments, in particular those impacted by acidic mine waters. The research will be conducted in the scope of an undergraduate project on fungal diversity and a graduate student thesis on the enzymatic, physiological, and geochemical controls on Mn(II) oxidation and biomineralization by key Mn(II)-oxidizing fungal isolates. The specific objectives are to define (1) the phylogenetic and ecological diversity of Mn(II)-oxidizing fungi in AMD systems, (2) the fungal mediated (a)biotic Mn(II) oxidative pathways, (3) the role of biological clocks on Mn(II) oxidation, and (4) the Mn(II) oxidation rates and solid-phase. This research will involve a multidisciplinary approach coupling molecular biology, enzymatic and chemical assays, microscopy and sophisticated micro-spectroscopic techniques to probe microbe-metal-mineral interactions at the molecular and bulk scale. The research outlined in this CAREER proposal will fill major gaps in our knowledge of the biological and geochemical controls of the Mn cycle ? information that is of crucial importance for improving in situ bioremediation (e.g. AMD treatment), stimulating primary productivity, and predicting the fate and transport of contaminants in the environment. Broader Impacts: In most circumstances, placing abstract chemical and biological concepts into real-life situations and applications can peak students interest and learning. The visually striking and disturbing devastation caused by AMD is an ideal environmental framework to educate students about the complexity of physical, microbiological, and chemical processes that govern the health of the natural world. The main educational outreach component of this proposal will be the creation and instruction of an annual five-day professional development workshop on AMD microbiology for informal and formal educators. The workshop, co-hosted by the Microbial Sciences Initiative at Harvard and the Jennings Environmental Education Center (JEEC), is entitled ?Living in the Acid: The Microbes that Create and Remediate Acid Mine Drainage? and will focus on the biogeochemistry and microbial ecology of AMD ecosystems, including lectures, lab and field exercises, and curriculum development forums. This workshop will be a unique experiential learning opportunity for educators seeking hands-on science instruction with microbes, environmental quality, and the cutting-edge concept of bioremediation. New findings from our proposed research will be directly integrated into the workshop and provide information, including high-resolution images, for permanent public displays for the JEEC. This workshop will serve as a conduit to educate a wide socioeconomic diversity of students spanning from rural to urban settings and to channel advances in our understanding of environmental microbiology and bioremediation to the classroom and to the general public.