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需的微量营养素，但在高浓度下，这些金属可能是有毒的，有时是致命的。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对神经系统疾病有健康风险的水平高出两个数量级。我们最近发现，在酸性矿井水（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，真菌群落将锰（II）完全和快速地氧化为锰（III/IV）氧化物。尽管真菌介导的过程被普遍观察到，并且它们对地质过程的影响是无可争议的，但人们对真菌物种参与金属的生物地球化学循环、所采用的机制以及它们对土壤和沉积物的矿物学框架和反应性的影响知之甚少。该CAREER提案提出了一个综合的教育和研究计划，以探索并最终确定真菌在地表环境中Mn（II）氧化中的重要性，特别是那些受酸性矿井水影响的环境。该研究将在真菌多样性的本科项目和Mn（II）氧化真菌分离物的酶、生理和地球化学控制和生物矿化的研究生论文的范围内进行。具体目标是确定(1)AMD系统中Mn（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Mn（II）氧化途径，(3)生物钟在Mn（II）氧化中的作用，以及(4)Mn（II）氧化速率和固相。这项研究将涉及多学科方法，结合分子生物学、酶和化学分析、显微镜和复杂的微光谱技术，在分子和体积尺度上探测微生物-金属-矿物的相互作用。本CAREER提案中概述的研究将填补我们对Mn循环的生物和地球化学控制知识的主要空白。对改善原位生物修复（如AMD治疗）、刺激初级生产力和预测环境中污染物的命运和运输至关重要的信息。更广泛的影响：在大多数情况下，将抽象的化学和生物学概念应用到现实生活中可以激发学生的兴趣和学习能力。AMD造成的视觉冲击和令人不安的破坏是一个理想的环境框架，教育学生关于控制自然世界健康的物理，微生物和化学过程的复杂性。该提案的主要教育外展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微生物学年度专业发展研讨会。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）共同主办，题为？生活在酸性环境中：产生和修复酸性矿井排水的微生物？并将重点关注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。本次研讨会将为寻求微生物、环境质量和生物修复前沿概念的实践科学指导的教育工作者提供一个独特的体验式学习机会。我们提出的研究的新发现将直接集成到研讨会中，并为JEEC的永久公开展示提供信息，包括高分辨率图像。本次研讨会将作为一个渠道，教育来自农村和城市环境的广泛的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展引导到课堂和公众。

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.