Biological Effects of Radiofrequency Electromagnetic Fields above 100 MHz on Fauna and Flora: Workshop Report.

ABSTRACT: This report summarizes the effects of anthropogenic radiofrequency electromagnetic fields with frequencies above 100 MHz on flora and fauna presented at an international workshop held on 5-7 November 2019 in Munich, Germany. Anthropogenic radiofrequency electromagnetic fields at these frequencies are commonplace; e.g., originating from transmitters used for terrestrial radio and TV broadcasting, mobile communication, wireless internet networks, and radar technologies. The effects of these radiofrequency fields on flora, fauna, and ecosystems are not well studied. For high frequencies exceeding 100 MHz, the only scientifically established action mechanism in organisms is the conversion of electromagnetic into thermal energy. In accordance with that, no proven scientific evidence of adverse effects in animals or plants under realistic environmental conditions has yet been identified from exposure to low-level anthropogenic radiofrequency fields in this frequency range. Because appropriate field studies are scarce, further studies on plants and animals are recommended.

Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report.

ABSTRACT: This report summarizes effects of anthropogenic electric, magnetic, and electromagnetic fields in the frequency range from 0 to 100 MHz on flora and fauna, as presented at an international workshop held on 5-7 November in 2019 in Munich, Germany. Such fields may originate from overhead powerlines, earth or sea cables, and from wireless charging systems. Animals and plants react differentially to anthropogenic fields; the mechanisms underlying these responses are still researched actively. Radical pairs and magnetite are discussed mechanisms of magnetoreception in insects, birds, and mammals. Moreover, several insects as well as marine species possess specialized electroreceptors, and behavioral reactions to anthropogenic fields have been reported. Plants react to experimental modifications of their magnetic environment by growth changes. Strong adverse effects of anthropogenic fields have not been described, but knowledge gaps were identified; further studies, aiming at the identification of the interaction mechanisms and the ecological consequences, are recommended.

The effect of exposure to radiofrequency electromagnetic fields on cognitive performance in human experimental studies: A protocol for a systematic review.

BACKGROUND: The World Health Organization (WHO) is currently assessing the potential health effects of exposure to radiofrequency electromagnetic fields (RF-EMFs) in the general and working population. Related to one such health effect, there is a concern that RF-EMFs may affect cognitive performance in humans. The systematic review (SR) aims to identify, summarize and synthesize the evidence base related to this question. Here, we present the protocol for the planned SR. OBJECTIVES: The main objective is to present a protocol for a SR which will evaluate the associations between short-term exposure to RF-EMFs and cognitive performance in human experimental studies. DATA SOURCES: We will search the following databases: PubMed, Embase, Web of Science, Scopus, and the EMF-Portal. The reference lists of included studies and retrieved review articles will be manually searched. STUDY ELIGIBILITY AND CRITERIA: We will include randomized human experimental studies that assess the effects of RF-EMFs on cognitive performance compared to no exposure or lower exposure. We will include peer-reviewed articles of any publication date in any language that report primary data. DATA EXTRACTION AND ANALYSIS: Data will be extracted according to a pre-defined set of forms developed and piloted by the review author team. To assess the risk of bias, we will apply the Rating Tool for Human and Animal Studies developed by NTP/OHAT, supplemented with additional questions relevant for cross-over studies. Where sufficiently similar studies are identified (e.g. the heterogeneity concerning population, exposure and outcome is low and the studies can be combined), we will conduct random-effects meta-analysis; otherwise, we will conduct a narrative synthesis. ASSESSMENT OF CERTAINTY OF EVIDENCE: The certainty of evidence for each identified outcome will be assessed according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Performing the review according to this protocol will allow the identification of possible effects of RF-EMFs on cognitive performance in humans. The protocol has been registered in PROSPERO, an open-source protocol registration system, to foster transparency.

Volatile organic compounds as signals in a plant-herbivore system: electrophysiological responses in olfactory sensilla of the moth Cactoblastis cactorum.

The morphological sensillum types on the antennae of male and female Cactoblastis cactorum were visualized by scanning electron microscopy. Electrophysiological recordings were performed for the first time on single olfactory sensilla of C. cactorum. The male sensilla trichodea house a receptor cell responding to the putative pheromone component (9Z,12E)-tetradecadienyl acetate. The sensilla trichodea of the females were much shorter than those of the males and contained specialized receptor cells responding to certain terpenoids, the most frequent being the nerolidol-sensitive cell. The sensilla auricillica and sensilla basiconica of both sexes contained cells responding less specifically to terpenoid compounds as well as to green leaf volatiles. Cells of the sensilla coeloconica responded to aliphatic aldehydes and acids. Eight volatile organic compounds emitted by Opuntia stricta, a host plant of C. cactorum, were identified using gas chromatography-mass spectrometry, beta-caryophyllene being the major compound. Five compounds identified by gas chromatography in the headspace of O. stricta elicited responses in olfactory receptor cells of C. cactorum, nonanal being the most active compound and therefore a candidate attractant of C. cactorum.

Pheromone-binding proteins contribute to the activation of olfactory receptor neurons in the silkmoths antheraea polyphemus and Bombyx mori.

The sensilla trichodea of the silkmoth Antheraea polyphemus are innervated by three types of receptor neurons each responding specifically to one of three pheromone components. The sensillum lymph of these sensilla surrounding the sensory dendrites contains three different types of pheromone-binding proteins (PBPs) in high concentrations. The sensilla trichodea of the silkmoth Bombyx mori are supplied by two receptor neurons each tuned specifically to one of the two pheromone components bombykol and bombykal, but only one type of PBP has been found so far in these sensilla. Recombinant PBPs of both silkmoth species in various combinations with pheromone components were applied to the receptor neurons via tip-opened sensilla during electrophysiological recordings. Over a fairly broad range of pheromone concentrations the responses of the receptor neurons depended on both, the pheromone component and the type of the PBP. Therefore, the PBPs appear to contribute to the excitation of the receptor neurons. Furthermore, bombykal in combination with the expressed PBP of B. mori failed to activate the corresponding receptor neuron of B. mori, but did so if combined with one of the PBPs of A. polyphemus. Therefore, a still unknown binding protein involved in bombykal transport might be present in B. mori.

Moth pheromone binding proteins contribute to the excitation of olfactory receptor cells.

Pheromone binding proteins (PBPs) occur in high concentrations in the sensillum lymph surrounding the sensory dendrites of moth pheromone-sensitive sensilla. They were shown to transport the lipophilic odorants through the aqueous sensillum lymph to the receptor cells. The sensilla trichodea of the silkmoth Antheraea polyphemus are supplied with three types of receptor cells responding specifically to three pheromone components. The sensillum lymph of these sensilla contains three different types of PBPs. In this study, recombinant PBPs in various combinations with pheromone components were applied to the receptor cells via tip-opened sensilla during electrophysiological recordings. The responses of receptor cells were shown to depend on both the pheromone component and the PBP. Pheromone components artificially bound to particular PBPs elicited nerve impulses in receptor cell types which they do not activate under natural conditions. This is the first electrophysiological study to suggest that the PBPs contribute to the activation of receptor molecules.

Activation and inhibition of the transduction process in silkmoth olfactory receptor neurons.

Electrophysiological responses of olfactory receptor neurons in both male and female silkmoths (Bombyx mori) were investigated. In both sexes, the G-protein activator sodium fluoride and 1,2-dioctanoyl-sn-glycerol, a membrane-permeable analog of the protein kinase C activator diacylglycerol, elicited nerve impulse responses similar to those elicited by weak continuous stimulation with odorants. Therefore, G(q)-proteins and diacylglycerol-activated ion channels seem to be involved in the transduction process in both pheromone-sensitive neurons in males and general odorant-sensitive neurons in females. Decyl-thio-trifluoro-propanone is known to inhibit electrophysiological responses of male moths to pheromones, but has no effect in females. Application of this inhibitor reduced the frequency, but not the amplitude of elementary receptor potentials. It had no inhibitory effect on nerve impulse responses elicited by sodium fluoride or 1,2-dioctanoyl-sn-glycerol. This supports the idea that decyl-thio-trifluoro-propanone acts on a prior step of the transduction cascade, e.g. on the pheromone receptor molecules. General odorants, such as (+/-)-linalool and 1-heptanol, excite olfactory receptor neurons in females, but inhibit the pheromone-sensitive neurons in males. Both (+/-)-linalool and 1-heptanol inhibited the responses of male neurons elicited by sodium fluoride or 1,2-dioctanoyl-sn-glycerol. (+/-)-Linalool reduced the amplitude of elementary receptor potentials. In contrast to decyl-thio-trifluoro-propanone, (+/-)-linalool and 1-heptanol seem to interfere with later processes of the transduction cascade, possibly the opening of ion channels.