Ogawa Kuniyasu, Yashima Takeshi
Keio University, Department of Mechanical Engineering, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama, Kanagawa 223-8522, Japan.
Ishikawa Agriculture and Forestry Research Center, 1-1 Mizuho, Noto-chou, Housu-gun, Ishikawa 927-0311, Japan.
Magn Reson Imaging. 2019 May;58:90-96. doi: 10.1016/j.mri.2019.01.004. Epub 2019 Jan 11.
In order to eliminate woodchip blocks where unwanted fungi have grown and select only blocks where shiitake mycelium are growing well, there is a need to develop a visualization technique for shiitake mycelium growing in woodchip blocks, and MRI is an obvious candidate technique. From the results of measurements of the woodchip bed in a small bottle (26 mm inside diameter) where shiitake mycelium was growing, the T relaxation time constant immediately after inoculation was 77.9 ± 5.5 ms, and the value after about 10 to 20 days increased to 135.0 ± 9.8 ms (the increase rate was 73%). The T maps of the wood-chip block (130 mm length, 75 mm height and 55 mm thickness) in which shiitake mycelium grew were calculated from T weighted images measured by changing TR from 28 to 400 ms. From the T maps of time series, it was found that the shiitake mycelium extended from the right-hand side to the left-hand side of the woodchip block in a planar manner. Furthermore, in a woodchip block in which penicillium was generated, since the T relaxation time constant of only the shiitake mycelium became longer, it was possible to visualize the shiitake mycelium distinctly from penicillium.
为了去除已生长有害真菌的木屑块，只选择香菇菌丝生长良好的木块，需要开发一种可视化木屑块中香菇菌丝生长情况的技术，而磁共振成像（MRI）显然是一种可行的技术。从对香菇菌丝生长的小瓶（内径26毫米）中的木屑床的测量结果来看，接种后立即测得的T弛豫时间常数为77.9±5.5毫秒，大约10至20天后该值增加到135.0±9.8毫秒（增长率为73%）。根据通过将重复时间（TR）从28毫秒改变到400毫秒测量得到的T加权图像，计算出香菇菌丝生长的木屑块（长130毫米、高75毫米、厚55毫米）的T图。从时间序列的T图中发现，香菇菌丝以平面方式从木屑块的右侧延伸到左侧。此外，在产生青霉的木屑块中，由于只有香菇菌丝的T弛豫时间常数变长，因此可以将香菇菌丝与青霉清晰地区分开来进行可视化。
