Biological effects of chronic exposure of Blaptica dubia (Blattodea: Blaberidae) nymphs to static and extremely low frequency magnetic fields.

Larisa Ilijin,Dajana Todorović,Aleksandra Filipović,Marija Mrdaković,Milena Vlahović,Vesna Perić-Mataruga,Anja Grčić

doi:10.1590/0001-3765202120190118

Larisa Ilijin, Dajana Todorović + Show 5 more

Open Access

https://doi.org/10.1590/0001-3765202120190118

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Abstract

In this paper, we analyzed the effects of chronic exposure (5 months) to static magnetic field (110 mT; SMF) and extremely low frequency magnetic field (ELF MF; 10 mT, 50 Hz) on Blaptica dubia nymphs. We have examined acetylcholinesterase (AChE) activity and heat shock protein 70 (HSP70) level, two sensitive biomarkers of stress in terrestrial insects. Relative growth rate (RGR), as a life history trait, was estimated. AChE activity was determined spectrophotometrically and HSP70 levels were quantified using indirect non-competitive ELISA and Western blotting. Calculated RGR was significantly changed upon exposure to both types of ambiental MFs. The effects of chronic exposure of B. dubia nymphs to SMF and ELF MF (50 Hz) were observed as decreased activity of AChE. The increased level of HSP70 was present only after exposure to SMF. The strength of ELF MF was most likely below the energy level needed to induce the expression of this stress protein. Different patterns of the expression of two HSP70 isoforms, where isoform 2 was sensitive only to SMF, are most likely a possibly switch - off in the expression of constitutive and/or inducible HSP70 isoforms.

Highlights

During the last century, the level of ambiental MFs has increased
The LSD post hoc test showed significant differences between heat shock protein 70 (HSP70) concentrations in cockroaches exposed to SMF and extremely low frequency magnetic field (ELF MF) (50 Hz)
Using Western blot analysis, we detected 2 HSP70 isoforms in the control group of cockroaches, as well as in groups exposed to SMF and ELF MF (50 Hz) (Figure 4a)

Summary

Introduction

The level of ambiental MFs has increased. The intensity of these magnetic and electromagnetic fields is severalfold greater than that of the geomagnetic field and they are described as electromagnetic pollution. The American cockroach, Periplaneta americana, is characterized by magnetic alignment in the resting position (Vácha et al 2010), and changes in locomotor activity were detected upon periodic changes in the geomagnetic field (Vácha et al 2009). In this cockroach biomagnetism was determined and characterized in vivo (Kong et al 2018).

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