Optical Imaging of Uranium Biotransformations by Microorganisms (OPTIUM)

微生物铀生物转化的光学成像 (OPTIUM)

• 批准号: NE/R011230/1
• 负责人: Louise Natrajan
• 金额: $ 79.06万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR011230%2F1
• 关键词: Optical; Imaging; Uranium; Biotransformations; Microorganisms

One of the most pressing problems facing society today is the management of existing and future waste forms arising from nuclear energy production. Although radioactivity is naturally occurring in the environment, 60+ years of anthropogenic activities including mining, industrial nuclear power production, accidental release and military use of nuclear materials has led to greatly increased levels of radionuclides in the natural environment. Although, in many cases, the contamination is concentrated and not widespread, the impact of these radionuclides pose to the wider ecosystems is intricately linked to the bioavailability of the radionuclide in question, which is dictated by their concentration and chemical form (oxidation state and speciation). Given that the heavy metal uranium comprises the majority waste by mass, the chemical transformation of uranium from its water soluble, and therefore mobile form (uranyl(VI)) to essentially an insoluble, and therefore immobile form (uranium(IV) mineral forms) is an important strategy in managing safe disposal to prevent leaching. Various microbial processes, often involving bacterially mediated redox transformations, have been suggested as viable bioremediation techniques. Typically these reactions are studied on the bulk level by X-ray absorption techniques, using purely quantitative techniques or on fixed (dead) cells by electron microscopy. There is currently a lack of techniques that are capable of quantitatively probing the distribution and micro- environment of radionuclides, particularly in living cells. Here we propose to introduce the powerful technique of two-photon fluorescence microscopy using the intrinsic emissive signals of the uranyl(VI) cation to follow and unravel these microbial processes at the sub-micron level in vivo in order to gain a full understanding of the proposed bioremediation process in situ at high spatial resolution. Two-photon microscopy is currently widely used in biology to visualise cellular processes in three dimensions, but has not yet been used to image cellular processes that involve uranium. The fundamental photophysical properties of the uranyl cation will enable two-photon excitation in the less damaging near infra-red region of the electromagnetic spectrum compared to UV/visible excitation which is damaging to cells in a one photon process. The long-lived uranyl emission itself (cf. dyes) and inherent spatial control of two-photon excitation allow high-resolution visualisation of uranyl-containing biological material, while fluorescence lifetime mapping demonstrates the ability to visualise the microscopic redox conditions over the surface of U(VI)-reducing bacterial cells. The first ever use of non-destructive 3D multi-photon optical imaging techniques combined with state of the art spectroscopy will be developed as a new technology in this research field and used as tools to address the challenge of understanding uranium speciation and reactivity in a range of biogeochemical systems, here, bacteria and fungi. We aim to exploit the intrinsic optical properties of the uranium ions as direct visible emissive probes as they interact with these microorganisms on chemical to more geologically relevant timescales. Our overall vision is to implement 3D optical imaging to both identify and image uranium ions and their speciation at a previously unseen level of detail (sub micron and sub ns timescale) and augment this with X-ray and electron microscopy approaches to create a new toolbox for understanding microbial and fungal systems that bioaccumulate, biotransform and biomineralise radiotoxic and environmentally hazardous actinide ions into less mobile forms. Working with a range of key stakeholders (e.g. Radioactive Waste Management Ltd., National Nuclear Laboratory), we can use this optical imaging technique to better predict radionuclide mobility at contaminated sites and inform disposal and land management in the UK and wider afield.

当今社会面临的最紧迫问题之一是管理核能生产所产生的现有和未来的废物形式。虽然放射性在环境中自然存在，但60多年来的人类活动，包括采矿、工业核能生产、核材料的意外释放和军事用途，导致自然环境中放射性核素的水平大大增加。虽然在许多情况下，污染是集中的，而不是广泛的，但这些放射性核素对更广泛的生态系统造成的影响与所涉放射性核素的生物利用度密切相关，而生物利用度取决于其浓度和化学形式（氧化态和形态）。鉴于重金属铀构成了大部分废物的质量，铀从其水溶性的、因此移动的形式（铀酰（VI））到基本上不溶性的、因此不移动的形式（铀（IV）矿物形式）的化学转化是管理安全处置以防止浸出的重要策略。各种微生物过程，通常涉及细菌介导的氧化还原转化，已被认为是可行的生物修复技术。通常，这些反应通过X射线吸收技术在本体水平上使用纯定量技术或通过电子显微镜在固定（死）细胞上进行研究。目前缺乏能够定量探测放射性核素的分布和微环境的技术，特别是在活细胞中。在这里，我们建议引入强大的双光子荧光显微镜技术，使用铀酰（VI）阳离子的固有发射信号，以遵循和解开这些微生物过程中的亚微米级在体内，以获得充分的理解，建议的生物修复过程中原位在高空间分辨率。双光子显微镜目前被广泛用于生物学中，以三维方式可视化细胞过程，但尚未用于涉及铀的细胞过程成像。铀酰阳离子的基本物理性质将使双光子激发在电磁光谱的损伤较小的近红外区域相比，紫外线/可见光激发，这是破坏细胞在一个光子的过程。长寿命的铀酰发射本身（参见。染料）和双光子激发的固有空间控制允许含铀酰的生物材料的高分辨率可视化，而荧光寿命映射证明了在U（VI）还原细菌细胞表面上可视化微观氧化还原条件的能力。首次使用非破坏性3D多光子光学成像技术与最先进的光谱学相结合将被开发为这一研究领域的新技术，并用作工具来解决理解铀形态和反应性的挑战在一系列生物地球化学系统中，在这里，细菌和真菌。我们的目标是利用铀离子作为直接可见发射探针的固有光学性质，因为它们与这些微生物在化学上相互作用，以更地质相关的时间尺度。我们的总体愿景是实现3D光学成像，以识别和成像铀离子及其形态，在以前看不见的细节水平（亚微米和亚纳秒时间尺度），并增加这与X射线和电子显微镜的方法，以创建一个新的工具箱，了解微生物和真菌系统，生物积累，生物转化和生物矿化放射性和环境危害的锕系元素离子到较少的移动的形式。与一系列关键利益攸关方（如放射性废物管理有限公司，国家核实验室），我们可以使用这种光学成像技术来更好地预测放射性核素在污染场地的流动性，并为英国和更广泛地区的处置和土地管理提供信息。

项目成果

Biogenic Sulfidation of U(VI) and Ferrihydrite Mediated by Sulfate-Reducing Bacteria at Elevated pH.

U（VI）的生物硫化和由硫酸盐还原细菌介导的pH值介导的亚硫酸盐。

• DOI: 10.1021/acsearthspacechem.1c00126
• 发表时间: 2021-11-18
• 期刊: ACS earth & space chemistry
• 影响因子: 3.4
• 作者: Townsend LT;Kuippers G;Lloyd JR;Natrajan LS;Boothman C;Mosselmans JFW;Shaw S;Morris K
• 通讯作者: Morris K

Multiple lines of evidence identify U(V) as a key intermediate during U(VI) reduction by Shewanella oneidensis MR1.

• DOI: 10.1021/acs.est.9b05285
• 发表时间: 2020-01
• 期刊: Environmental science & technology
• 影响因子: 11.4
• 作者: Gianni F. Vettese;K. Morris;L. Natrajan;S. Shaw;T. Vitova;J. Galanzew;Debbie L. Jones;J. Lloyd

A Click Chemistry Strategy for the Synthesis of Efficient Photoinitiators for Two-Photon Polymerization

• DOI: 10.1002/adfm.202006108
• 发表时间: 2020-09-13
• 期刊: ADVANCED FUNCTIONAL MATERIALS
• 影响因子: 19
• 作者: Henning, Irene;Woodward, Adam W.;Moore, Jonathan C.
• 通讯作者: Moore, Jonathan C.

Microbial Degradation of Citric Acid in Low Level Radioactive Waste Disposal: Impact on Biomineralization Reactions.

• DOI: 10.3389/fmicb.2021.565855
• 发表时间: 2021
• 期刊: Frontiers in microbiology
• 影响因子: 5.2
• 作者: Byrd N;Lloyd JR;Small JS;Taylor F;Bagshaw H;Boothman C;Morris K
• 通讯作者: Morris K