Caenorhabditis elegans nematodes are broadly used to investigate the impact of environmental factors on animal physiology and behavior. Here, C. elegans with internalized paramagnetic nanoparticles were placed inside a magnetic field (MF) to explore its effects on locomotion. We hypothesized that internalized paramagnetic nanoparticles combined with external MF affect C. elegans’ locomotion machinery. To test our hypothesis, we used adult C. elegans fed on bacteria mixed with paramagnetic nanoparticles of 1 μm, 100, and 40 nm diameter. The presence of nanoparticles inside the worms’ body (alimentary canal, body muscle) was verified by fluorescent and electron microscopy. A custom-made software was used to track freely moving C. elegans in the absence or presence of MF, sequentially, for 200 + 200 s. We used established metrics to quantify locomotion-related parameters, including posture, motion, and path features. Key attributes of C. elegans locomotion (stay ratio, forward over backward motion, speed) were affected only in worms with internalized nanoparticles of 100 nm in the presence of MF (reduced speed, increased stay ratio, decreased forward/backward ratio), in contrast to untreated worms. Our work shows that internalized particles of specific properties affect C. elegans locomotion under MF. Hence, it contributes to clarifying the effects of MF and activated nanoparticles on C. elegans locomotion, thus fueling further research.

中文翻译：

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内化顺磁性纳米粒子对秀丽隐杆线虫在磁场存在下的运动的影响

秀丽隐杆线虫线虫被广泛用于研究环境因素对动物生理和行为的影响。在这里，将具有内化顺磁性纳米粒子的线虫置于磁场 (MF) 内，以探索其对运动的影响。我们假设内化的顺磁性纳米粒子与外部 MF 相结合会影响线虫的运动机制。为了检验我们的假设，我们使用了成年秀丽隐杆线虫，它们以混合有 1 μ顺磁性纳米颗粒的细菌为食 米、100 和 40 纳米直径。通过荧光和电子显微镜验证了蠕虫体内（消化道、身体肌肉）内纳米粒子的存在。使用定制软件在 MF 不存在或存在的情况下按顺序跟踪自由移动的线虫200 + 200 秒。我们使用已建立的指标来量化与运动相关的参数，包括姿势、运动和路径特征。C. elegans运动的关键属性（停留比、向前运动相对于向后运动、速度）仅在存在 MF（速度降低、停留比增加、前进/后退比降低）的情况下内化纳米颗粒为 100 nm 的蠕虫中受到影响，在与未经处理的蠕虫形成对比。我们的工作表明，具有特定属性的内化颗粒会影响C. elegans在 MF 下的运动。因此，它有助于阐明 MF 和活化纳米粒子对秀丽隐杆线虫运动的影响，从而推动进一步的研究。