An electromagnetic field disrupts negative geotaxis in Drosophila via a CRY-dependent pathway.

Abstract

Many higher animals have evolved the ability to use the Earth's magnetic field, particularly for orientation. Drosophila melanogaster also respond to electromagnetic fields (EMFs), although the reported effects are quite modest. Here we report that negative geotaxis in flies, scored as climbing, is disrupted by a static EMF, and this is mediated by cryptochrome (CRY), the blue-light circadian photoreceptor. CRYs may sense EMFs via formation of radical pairs of electrons requiring photoactivation of flavin adenine dinucleotide (FAD) bound near a triad of Trp residues, but mutation of the terminal Trp in the triad maintains EMF responsiveness in climbing. In contrast, deletion of the CRY C terminus disrupts EMF responses, indicating that it plays an important signalling role. CRY expression in a subset of clock neurons, or the photoreceptors, or the antennae, is sufficient to mediate negative geotaxis and EMF sensitivity. Climbing therefore provides a robust and reliable phenotype for studying EMF responses in Drosophila.

AI evidence extraction

Main findings

Negative geotaxis (climbing) in Drosophila is disrupted by a static electromagnetic field, and this behavioral effect is mediated by cryptochrome (CRY). Mutation of the terminal tryptophan in the proposed Trp triad did not abolish EMF responsiveness in climbing, whereas deletion of the CRY C terminus disrupted EMF responses; CRY expression in specific neurons/photoreceptors/antennae was sufficient to confer EMF sensitivity.

Outcomes measured

• Negative geotaxis (climbing) behavior
• Cryptochrome (CRY)-dependent mediation of EMF response
• Effect of CRY mutations/deletions on EMF responsiveness
• Tissue-specific CRY expression sufficient for EMF sensitivity (clock neurons, photoreceptors, antennae)

Limitations

• Exposure parameters (field strength, frequency details beyond 'static', and duration) are not provided in the abstract.
• Sample size is not reported in the abstract.
• Findings are in an animal model (Drosophila), limiting direct inference to humans.

{
    "study_type": "animal",
    "exposure": {
        "band": null,
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Drosophila melanogaster (fruit flies)",
    "sample_size": null,
    "outcomes": [
        "Negative geotaxis (climbing) behavior",
        "Cryptochrome (CRY)-dependent mediation of EMF response",
        "Effect of CRY mutations/deletions on EMF responsiveness",
        "Tissue-specific CRY expression sufficient for EMF sensitivity (clock neurons, photoreceptors, antennae)"
    ],
    "main_findings": "Negative geotaxis (climbing) in Drosophila is disrupted by a static electromagnetic field, and this behavioral effect is mediated by cryptochrome (CRY). Mutation of the terminal tryptophan in the proposed Trp triad did not abolish EMF responsiveness in climbing, whereas deletion of the CRY C terminus disrupted EMF responses; CRY expression in specific neurons/photoreceptors/antennae was sufficient to confer EMF sensitivity.",
    "effect_direction": "harm",
    "limitations": [
        "Exposure parameters (field strength, frequency details beyond 'static', and duration) are not provided in the abstract.",
        "Sample size is not reported in the abstract.",
        "Findings are in an animal model (Drosophila), limiting direct inference to humans."
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electromagnetic field",
        "static EMF",
        "magnetoreception",
        "Drosophila melanogaster",
        "negative geotaxis",
        "climbing",
        "cryptochrome",
        "CRY",
        "circadian photoreceptor",
        "FAD",
        "radical pair",
        "Trp triad",
        "C terminus",
        "clock neurons",
        "photoreceptors",
        "antennae"
    ],
    "suggested_hubs": []
}

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