Continuous wave and simulated GSM exposure at 1.8 W/kg and 1.8 GHz do not induce hsp16‐1 heat‐shock gene expression in Caenorhabditis elegans

Abstract

Recent data suggest that there might be a subtle thermal explanation for the apparent induction by radiofrequency (RF) radiation of transgene expression from a small heat‐shock protein (hsp16‐1) promoter in the nematode, Caenorhabditis elegans. The RF fields used in the C. elegans study were much weaker (SAR 5–40 mW kg−1) than those routinely tested in many other published studies (SAR ∼2 W kg−1). To resolve this disparity, we have exposed the same transgenic hsp16‐1::lacZ strain of C. elegans (PC72) to higher intensity RF fields (1.8 GHz; SAR ∼1.8 W kg−1). For both continuous wave (CW) and Talk‐pulsed RF exposures (2.5 h at 25 °C), there was no indication that RF exposure could induce reporter expression above sham control levels. Thus, at much higher induced RF field strength (close to the maximum permitted exposure from a mobile telephone handset), this particular nematode heat‐shock gene is not up‐regulated. However, under conditions where background reporter expression was moderately elevated in the sham controls (perhaps as a result of some unknown co‐stressor), we found some evidence that reporter expression may be reduced by ∼15% following exposure to either Talk‐pulsed or CW RF fields. Bioelectromagnetics 29:92–99, 2008. © 2007 Wiley‐Liss, Inc.

Review of possible modulation‐dependent biological effects of radiofrequency fields

“…This increases the likelihood that the few positive findings are due to chance. In experiments with the nematode Caenorhabditis elegans, no overall effects were found on hsp16-1 expression from either CW or GSM-modulated RF fields [Dawe et al, 2008]. However, in a post hoc analysis some evidence was found that the expression of hsp16-1 was possibly reduced by about 15% under conditions of moderately elevated background expression in the control worms.…”

Response ofCaenorhabditis elegansto wireless devices radiation exposure

“…elegans (Dawe et al, 2009(Dawe et al, , 2008(Dawe et al, , 2006 though we cannot rule out the Int J Radiat Biol Downloaded from informahealthcare.com by Laurentian University on 12/09/14…”

“…The same year, Bojjawar et al (2006) showed that electromagnetic nanopulses interfered with the worm's fertility and development by an unknown mechanism. Later, Dawe et al (2008) in an attempt to further investigate the possible induction of a small heat-shock protein (hsp) gene in C. elegans, hsp-16.1, performed experiments using higher intensity RF fields and concluded that there was no detectable induction of its expression. The results described so far, concerning the effect of EMF used for communications, on the nematode, indicate that there is still a lot of research to be done before a safe conclusion can be drawn.…”

Absence of direct effect of low-power millimeter-wave radiation at 60.4 GHz on endoplasmic reticulum stress

“…It was proposed that exposures at frequencies around 1 GHz can alter protein conformation, which causes in turn the synthesis of heat shock proteins (French et al 2001;de Pomerai et al 2003). However, the proteotoxic effect of EMF is still controversial, and recent studies have shown that, if care is taken to avoid thermal effects, low-power microwaves (1.8 GHz, 1.8 W/kg) and MMW exposures (60 GHz, 0.54 mW/ cm 2 ) have no proteotoxic effects and no notable change in heat shock protein expression can be detected (Dawe et al 2007;Zhadobov et al 2007). Moreover, higher-power MMW radiations were found to reduce tumor metastasis (42.2 GHz, 36.5±5 mW/ cm 2 ; Logani et al 2006), or to protect cells from the toxicity of commonly used anticancer drugs (42.2 GHz, 31±5 mW/cm 2 ; Makar et al 2003).…”