Effects of large gradient high magnetic field (LG‐HMF) on the long‐term culture of aquatic organisms: Planarians example

Abstract

Large gradient high magnetic field (LG-HMF) is a powerful tool to study the effects of altered gravity on organisms. In our study, a platform for the long-term culture of aquatic organisms was designed based on a special superconducting magnet with an LG-HMF, which can provide three apparent gravity levels (µ g, 1 g, and 2 g), along with a control condition on the ground. Planarians, Dugesia japonica, were head-amputated and cultured for 5 days in a platform for head reconstruction. After planarian head regeneration, all samples were taken out from the superconducting magnet for a behavioral test under geomagnetic field and normal gravity conditions. To analyze differences among the four groups, four aspects of the planarians were considered, including head regeneration rate, phototaxis response, locomotor velocity, and righting behavior. Data showed that there was no significant difference in the planarian head regeneration rate under simulated altered gravity. According to statistical analysis of the behavioral test, all of the groups had normal functioning of the phototaxis response, while the planarians that underwent head reconstruction under the microgravity environment had significantly slower locomotor velocity and spent more time in righting behavior. Furthermore, histological staining and immunohistochemistry results helped us reveal that the locomotor system of planarians was affected by the simulated microgravity environment. We further demonstrated that the circular muscle of the planarians was weakened (hematoxylin and eosin staining), and the epithelial cilia of the planarians were reduced (anti-acetylated tubulin staining) under the simulated microgravity environment. Bioelectromagnetics. 2018;39:428-440. © 2018 Wiley Periodicals, Inc.

Extreme Environmental Stress-Induced Biological Responses in the Planarian

“…Their results demonstrate that all of the planarians normally regenerated their heads and the regeneration rate of the four groups is similar. These results indicate that planarians can correctly regenerate their heads at different gravity environments [25].…”

“…These results showed that LG-HMF-generated microgravity and hypergravity did not affect the reestablishment of photonegative ability. But the photonegative response time of the planarians which regenerated under LG-HMF conditions was slightly suppressed, and the authors thought it was mainly due to the difference of the locomotor system instead of the reconstructed head [25]. They took the traditional planarian locomotor velocity (pLMV) assay and automated center-of-mass (COM) tracking approach and image analysis to analyze the locomotor behaviors, and the results showed that Group ug/12T has a significantly decreased locomotor function compared to the other three groups during the 8 min test.…”

“…Histologic section staining and immunohistochemistry results showed that the circular muscle of planarians regenerated in simulated microgravity was weakened compared with the other planarian groups, and the fluorescence thickness of the epithelial cilia are significantly decreased. The authors thought that differences in locomotion velocity and righting behavior come from frail muscle [25]. There is research showing that planarian that has been exposed to 16G intensity static magnetic fields for one day significantly improved the velocity of movement [37].…”

Molecular impact of launch related dynamic vibrations and static hypergravity in planarians

“…The presence of these unique adult stem cells and their plasticity renders planarians in a unique model to study the impact of environmental factors like hypergravity and vibration in adult cells in the context of a "whole animal", in contrast to the partial view inherent to "in vitro" cell cultures. Also, there is an increasing interest to study these animals under various altered gravity conditions [22][23][24][25][26] .…”

“…npj Microgravity (2020)25 Published in cooperation with the Biodesign Institute at Arizona State University, with the support of NASA1234567890():,;…”