Transgenic nematodes as biomonitors of microwave-induced stress
Transgenic nematodes as biomonitors of microwave-induced stress
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DOI：
10.1016/s0027-5107(97)00266-2
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发表时间：
1998-03-13
影响因子：
2.3
通讯作者：
de Pomerai, D
中科院分区：
文献类型：
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作者：
Daniells, C;Duce, I;de Pomerai, D
转基因线虫（秀丽隐杆线虫菌株PC 72）携带在C.线虫hsp 16热休克启动子已被用于监测水和土壤中的毒物反应。因为这些转基因线虫通过合成容易检测的报告产物对热和有毒化学物质都有反应，所以它们提供了用于由微波辐射或其他电磁场诱导的应激反应（无论是热的还是非热的）的有用的初步筛选。我们使用了一个横向电磁（TEM）的细胞从一端由源和终止在另一端的匹配负载。大多数研究使用750 MHz的频率进行，标称功率设置为27 dBm。将TEM室保持在屏蔽室内25 ℃的培养箱中;将相应的对照屏蔽并放置在相同的25 ℃培养箱中;将额外的基线对照保持在15 ℃（蠕虫生长温度）。应激反应的测定是根据β-半乳糖苷酶（报告基因）诱导高于对照水平。对连续微波辐射的反应的时间过程在2和16 h时与25 ℃对照组均显示出显著差异，但在4或8 h时则无显著差异。使用暴露2小时的5 × 5多孔板阵列，与类似的对照阵列相比，25个微波样品显示出高度显著的响应。受影响最严重的威尔斯是那些在最接近源行，而最远的行没有上升到控制水平以上，这表明阴影效应。这些不同的反应很难与一般的热效应相协调，虽然局部的功率吸收提供了一个可能的解释。在实验中，频率和/或功率设置是不同的建议在21比在27 dBm，在750和300 MHz的响应更大，虽然在24 dBm和750 MHz观察到非常可变的响应。因此，较低的功率水平往往会引起较大的反应（上述情况除外），这与任何简单加热效应的预期趋势相反。这些结果是可重复的，数据采集既快速又简单。迄今为止的证据表明，微波辐射对转基因线虫造成了可测量的压力，可能反映了细胞内蛋白质损伤水平的增加（被认为是触发hsp基因诱导的常见信号）。观察到的响应水平与中等浓度（ppm）的金属离子（如Zn 2+和Cu 2+）的响应水平相当。我们的结论是，这种方法值得进一步和更详细的调查，但它已经证明了明确的生物效应的微波辐射方面的激活细胞应激反应（热休克蛋白基因诱导）。(C)1998年Elsevier Science B.V.
Transgenic nematodes (Caenorhabditis elegans strain PC72), carrying a stress-inducible reporter gene(Escherichia coli P-galactosidase) under the control of a C. elegans hsp16 heat-shock promoter, have been used to monitor toxicant responses both in water and soil. Because these transgenic nematodes respond both to heat and toxic chemicals by synthesising an easily detectable reporter product, they afford a useful preliminary screen for stress responses (whether thermal or non-thermal) induced by microwave radiation or other electromagnetic fields. We have used a transverse electromagnetic (TEM) cell fed from one end by a source and terminated at the other end by a matched load. Most studies were conducted using a frequency of 750 MHz, at a nominal power setting of 27 dBm. The TEM cell was held in an incubator at 25 degrees C inside a shielded room; corresponding controls were shielded and placed in the same 25 degrees C incubator; additional baseline controls were held at 15 degrees C (worm growth temperature). Stress responses were measured in terms of P-galactosidase (reporter) induction above control levels. The time-course of response to continuous microwave radiation showed significant differences from 25 degrees C controls both at 2 and 16 h, but not at 4 or 8 h. Using a 5 x 5 multiwell plate array exposed for 2 h, the 25 microwaved samples showed highly significant responses compared with a similar control array. The wells most strongly affected were those in the rows closest to the source, whereas the most distant row did not rise above control levels, suggesting a shadow effect. These differential responses are difficult to reconcile with general heating effects, although localised power absorption affords a possible explanation. Experiments in which the frequency and/or power settings were varied suggested a greater response at 21 than at 27 dBm, both at 750 and 300 Mhz, although extremely variable responses were observed at 24 dBm and 750 MHz. Thus, lower power levels tended, if anything, to induce larger responses (with the above-mentioned exception), which is opposite to the trend anticipated for any simple heating effect. These results are reproducible and data acquisition is both rapid and simple. The evidence accrued to date suggests that microwave radiation causes measurable stress to transgenic nematodes, presumably reflecting increased levels of protein damage within cells (the common signal thought to trigger hsp gene induction). The response levels observed are comparable to those observed with moderate concentrations (ppm) of metal ions such as Zn2+ and Cu2+. We conclude that this approach deserves further and more detailed investigation, but that it has already demonstrated clear biological effects of microwave radiation in terms of the activation of cellular stress responses (hsp gene induction). (C) 1998 Elsevier Science B.V.