A small temperature rise may contribute towards the apparent induction by microwaves of heat-shock gene expression in the nematodeCaenorhabditis Elegans

Self Cite

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.

Section: Worm Culture and Processingmentioning

confidence: 99%

Section: Worm Culture and Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Dawe¹,

Nylund²,

Leszczyński³

et al. 2007

Self Cite

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

Dawe¹,

Bodhicharla

Graham

et al. 2009

Self Cite

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.

Microwave fields have little effect on α‐synuclein aggregation in a Caenorhabditis elegans model of Parkinson's disease

Pomerai

Iqbal

Lafayette

et al. 2016

Self Cite

Potential health effects of radiofrequency (RF) radiation from mobile phones arouse widespread public concern. RF fields from handheld devices near the brain might trigger or aggravate brain tumors or neurodegenerative diseases such as Parkinson's disease (PD). Aggregation of neural α-synuclein (S) is central to PD pathophysiology, and invertebrate models expressing human S have helped elucidate factors affecting the aggregation process. We have recently developed a transgenic strain of Caenorhabditis elegans carrying two S constructs: SC tagged with cyan (C) blue fluorescent protein (CFP), and SV with the Venus (V) variant of yellow fluorescent protein (YFP). During S aggregation in these SC+SV worms, CFP, and YFP tags are brought close enough to allow Foerster Resonance Energy Transfer (FRET). As a positive control, S aggregation was promoted at low Hg(2+) concentrations, whereas higher concentrations activated stress-response genes. Using two different exposure systems described previously, we tested whether RF fields (1.0 GHz CW, 0.002-0.02 W kg(-1); 1.8 GHz CW or GSM, 1.8 W kg(-1)) could influence S aggregation in SC+SV worms. YFP fluorescence in similar SV-only worms provided internal controls, which should show opposite changes due to FRET quenching during S aggregation. No statistically significant changes were observed over several independent runs at 2.5, 24, or 96 h. Although our worm model is sensitive to chemical promoters of aggregation, no similar effects were attributable to RF exposures.