Imaging complex nutrient dynamics in mycelial networks
Imaging complex nutrient dynamics in mycelial networks
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DOI：
10.1111/j.1365-2818.2008.02043.x
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发表时间：
2008-08-01
影响因子：
2
通讯作者：
Boddy, L.
中科院分区：
文献类型：
--
作者：
Fricker, M. D.;Lee, J. A.;Boddy, L.
运输网络是多细胞生物体的重要组成部分，分配营养物质并清除废物。动物的心血管和呼吸系统，以及植物的脉管系统，都是分支树，其结构被认为决定了这些生物体中的普遍比例定律。相比之下，许多多细胞真菌的运输系统不适合这个概念框架，因为它们已经进化到探索一个斑块环境以寻找新资源，而不是通过三维生物体分支。这些真菌生长为觅食菌丝体，由线状菌丝的分支和融合形成，从而产生复杂的网络。为了有效地发挥作用，菌丝体网络必须在空间上分离的源和汇区域之间运输营养物质，并且在面对食菌昆虫的连续攻击或随机破坏时保持其完整性。在这里，我们回顾了新的成像方法和软件工具的发展，我们已经使用了一系列的空间尺度上的营养物质运输和网络的形成觅食菌丝。在毫米尺度上，我们已经使用了延时共聚焦成像和荧光光漂白后恢复的组合，以量化通过独特的液泡系统在个别菌丝扩散运输的速度。然后，这些数据构成模拟模型的基础，以预测这种基于扩散的移动在几毫米尺度上的影响。在厘米尺度上，我们使用了新的光子计数闪烁成像技术，以可视化放射性标记的运动在小的微观世界。这种方法揭示了新的N-运输现象，包括快速，优惠的N-资源分配到C-丰富的汇，诱导同时双向运输，不同的预先存在的运输路线之间的突然切换，和一个强大的脉动组件运输在某些物种。使用傅立叶技术的脉动传输组件的分析表明，作为殖民地的形式，它自组织成良好划分的域是可识别的脉冲的相位关系的差异。在厘米到米的尺度上，我们已经开始使用从图论中借来的技术来描述网络的发展和动态，并使用这些抽象的网络模型来预测网络的传输特性，弹性和成本。
Transport networks are vital components of multi-cellular organisms, distributing nutrients and removing waste products. Animal cardiovascular and respiratory systems, and plant vasculature, are branching trees whose architecture is thought to determine universal scaling laws in these organisms. In contrast, the transport systems of many multi-cellular fungi do not fit into this conceptual framework, as they have evolved to explore a patchy environment in search of new resources, rather than ramify through a three-dimensional organism. These fungi grow as a foraging mycelium, formed by the branching and fusion of threadlike hyphae, that gives rise to a complex network. To function efficiently, the mycelial network must both transport nutrients between spatially separated source and sink regions and also maintain its integrity in the face of continuous attack by mycophagous insects or random damage. Here we review the development of novel imaging approaches and software tools that we have used to characterise nutrient transport and network formation in foraging mycelia over a range of spatial scales. On a millimetre scale, we have used a combination of time-lapse confocal imaging and fluorescence recovery after photobleaching to quantify the rate of diffusive transport through the unique vacuole system in individual hyphae. These data then form the basis of a simulation model to predict the impact of such diffusion-based movement on a scale of several millimetres. On a centimetre scale, we have used novel photon-counting scintillation imaging techniques to visualize radiolabel movement in small microcosms. This approach has revealed novel N-transport phenomena, including rapid, preferential N-resource allocation to C-rich sinks, induction of simultaneous bi-directional transport, abrupt switching between different pre-existing transport routes, and a strong pulsatile component to transport in some species. Analysis of the pulsatile transport component using Fourier techniques shows that as the colony forms, it self-organizes into well demarcated domains that are identifiable by differences in the phase relationship of the pulses. On the centimetre to metre scale, we have begun to use techniques borrowed from graph theory to characterize the development and dynamics of the network, and used these abstracted network models to predict the transport characteristics, resilience, and cost of the network.