Low‐intensity microwave irradiation does not substantially alter gene expression in late larval and adult Caenorhabditis elegans

Abstract

Reports that low‐intensity microwave radiation induces heat‐shock reporter gene expression in the nematode, Caenorhabditis elegans, have recently been reinterpreted as a subtle thermal effect caused by slight heating. This study used a microwave exposure system (1.0 GHz, 0.5 W power input; SAR 0.9–3 mW kg−1 for 6‐well plates) that minimises temperature differentials between sham and exposed conditions (≤0.1 °C). Parallel measurement and simulation studies of SAR distribution within this exposure system are presented. We compared five Affymetrix gene arrays of pooled triplicate RNA populations from sham‐exposed L4/adult worms against five gene arrays of pooled RNA from microwave‐exposed worms (taken from the same source population in each run). No genes showed consistent expression changes across all five comparisons, and all expression changes appeared modest after normalisation (≤40% up‐ or down‐regulated). The number of statistically significant differences in gene expression (846) was less than the false‐positive rate expected by chance (1131). We conclude that the pattern of gene expression in L4/adult C. elegans is substantially unaffected by low‐intensity microwave radiation; the minor changes observed in this study could well be false positives. As a positive control, we compared RNA samples from N2 worms subjected to a mild heat‐shock treatment (30 °C) against controls at 26 °C (two gene arrays per condition). As expected, heat‐shock genes are strongly up‐regulated at 30 °C, particularly an hsp‐70 family member (C12C8.1) and hsp‐16.2. Under these heat‐shock conditions, we confirmed that an hsp‐16.2::GFP transgene was strongly up‐regulated, whereas two non‐heat‐inducible transgenes (daf‐16::GFP; cyp‐34A9::GFP) showed little change in expression. Bioelectromagnetics 30:602–612, 2009. © 2009 Wiley‐Liss, Inc.

Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast

“…To date, relatively few studies using large-scale screening have analyzed the effects of ELF-EMF and RF-EMF on gene transcription in organisms, and the results have been contradictory. Some researchers have shown that the transcription levels of some genes are affected by EMF exposure (Olivares-Bañuelos et al, 2004; Remondini et al, 2006; Collard et al, 2011), while others have shown that the transcription profile is unchanged by EMF exposure (Luceri et al, 2005; Paparini et al, 2008; Dawe et al, 2009). Only a few investigations on the effects of EMF on yeast cells have been undertaken, even though their short cell cycle, easy handling, extensive characterization, and eukaryotic genetic background make yeast a good model organism for this type of study.…”

Using model organism Saccharomyces cerevisiae to evaluate the effects of ELF‐MF and RF‐EMF exposure on global gene expression

“…In addition, Belyaev et al [2006] reported that in vivo exposure of rat to RF-EMF up-regulated 11 genes and down-regulated one gene in rat cerebellum. Recently, an in vivo study from de Pomerai's group suggested that very low level RF-EMF had no effect on the gene expression in Caenorhabditis elegans [Dawe et al, 2009]. Recently, an in vivo study from de Pomerai's group suggested that very low level RF-EMF had no effect on the gene expression in Caenorhabditis elegans [Dawe et al, 2009].…”

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…”