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Abstract To successfully navigate their surroundings, animals detect and orient to environmental stimuli possessing unique physical properties. Most animals can derive directional information from spatial or temporal changes in stimulus intensity (e.g. chemo- and thermo-taxis). However, some biologically relevant stimuli have constant intensity at most organismal scales. The gravitational and magnetic fields of the earth are examples of uniform stimuli that remain constant at most relevant scales. While devoid of information associated with intensity changes, the vectorial nature of these fields intrinsically encodes directional information. While much is known about behavioral strategies that exploit changes in stimulus intensity (gradients), less is understood about orientation to uniform stimuli. Nowhere is this truer than with magnetic orientation. While many organisms are known to orient to the magnetic field of the earth, how these animals extract information from the earth’s magnetic field remains unresolved. Here we use the nematodeC. elegansto investigate behavioral strategies for orientation to magnetic fields, and compare our findings to the better characterized chemical and thermal orientation strategies. We used an unbiased cluster analysis to categorize, quantify, and compare behavioral components underlying different orientation strategies as a way to quantify and compare animal orientation to distinct stimuli. We find that in the presence of an earth-like magnetic field, worms perform acute angle turns (140-171°) that significantly improved their alignment with the direction of an imposed magnetic vector. In contrast, animals performed high amplitude turns (46-82°) that significantly increased alignment of their trajectory with the preferred migratory angle. We conclude thatC. elegansorients to earth-strength magnetic fields using two independent behavioral strategies, in contrast to orientation strategies to graded stimuli. Understanding howC. elegansdetects and orients to magnetic fields will provide useful insight into how many species across taxa accomplish this fascinating sensory feat.
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Effects of Martian magnetic and gravitational fields across multiple generations of the nematode C. elegans
Life on Earth evolved under a specific set of environmental conditions, including consistent gravitational and magnetic fields. However, planned human missions to Mars in the coming decades will expose terrestrial organisms to radically different conditions, with Martian gravity being approximately 38% of Earth's and a significantly reduced magnetic field. Understanding the combined effects of these factors is crucial, as they may impact biological systems that evolved under different conditions. In this study, we investigated the effects of simulated Martian gravity and hypomagnetic fields on the nematode Caenorhabditis elegans across six generations. We used an integrated experimental setup consisting of clinostats to mimic the reduced Martian gravity, and Merritt coil magnetic cages to model the decreased Martian magnetic fields. We assessed behavioral, morphological, and physiological responses of C. elegans. High-throughput automated assays revealed significant reductions in motor output and morphological dimensions for animals in the Mars treatment compared to matched earth-like controls. We assessed neurological function by means of chemotaxis assays and found a progressive decline in performance for worms raised under the Martian paradigm compared to Earth controls. Our results show that worms grown under Martian-like conditions exhibit progressive physiological alterations across generations, suggesting that the unique environment of Mars might pose challenges to biological function and adaptation. These findings contribute to understanding how living organisms may respond to the combined effects of reduced gravity and hypomagnetic fields, providing insights relevant for future human exploration and potential colonization of Mars.
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- Award ID(s):
- 1818140
- PAR ID:
- 10553913
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Institution:
- bioRxiv
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Posted Content:
- https://doi.org/10.1101/2024.10.18.619154
