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| Status |
Public on Oct 22, 2019 |
| Title |
Mechanistic Evaluation of Daphnia magna’s Behavioral and Life History Responses to Photoperiod [Experiment 2] |
| Organism |
Daphnia magna |
| Experiment type |
Expression profiling by array
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| Summary |
Across evolutionary time, nearly all animal species have harnessed photoperiod to initiate processes that ultimately influence seasonal behavior and life history traits. In the freshwater cladoceran Daphnia magna, the effect of photoperiod on various life history traits has generally been investigated in conjunction with additional environmental stimuli. In the present study, we sought to untangling responses directly attributable to photoperiod in D. magna and identify the molecular processes underlying resultant behavioral and life history responses using functional analysis of global transcriptomic expression. D. magna were exposed to five different photoperiods immediately post-hatch for 21d where a standard long-day photoperiod of 16 hours light and 8 hours dark (16L:8D) served as the control relative to 4L:20D, 8L:16D, 12L:12L, and 20L:4D photoperiods. Entrainment to short-day photo-periods (4L:20D, 8L:16D, and 12L:12L) resulted in significantly increased light-avoidance behaviors relative to the control photoperiod where young Daphnia (7d old) displayed the most pronounced avoidance responses. Correspondingly, functional transcriptomics identified differential transcriptional expression of genes involved in glutamate signaling, which is critical in arthropod light-avoidance responses, as well as period circadian protein and proteins coding F-box/LRR-repeat domains, all of which contribute to establishing circadian rhythms in arthropods. Short-day photoperiods also induced increased metabolic rates which corresponded with broad-scale changes in transcriptional expression across multiple systems-level energy metabolism pathways. The most striking observation was increased male production across short-day photoperiods (4L:20D, 8L:16D, and 12L:12D). Transcriptional expression consistent with multiple putative mechanisms of male production were observed including expression suggestive of increased glutamate signaling; a response observed to induce male production in D. pulex via photo-period sensitive mechanisms. Overall, the results demonstrate the importance of photoperiod on behavior and life history trajectories in D. magna where we have now established multiple putative mechanistic pathways underlying several critical responses.
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| Overall design |
The experimental approach was to investigate the effects of photoperiod on key life history traits, metabolic rates, photo-taxis responses and global transcriptomic expression in D. magna to characterize foundational responses to light. Separate groups of D. magna were simultaneously exposed to five different photoperiods representing varying seasonal day lengths; this included a comparative control of 16 hours light and 8 hours dark (16L:8D) that is the standard for acute (USEPA 1996a; USEPA 2002; OECD No. 202(2004)) and chronic (USEPA 1996b; ASTM E1193-97(2012) , OECD No. 211 (2012)) ecotoxicological methods and an array of alternative photoperiods including extreme short days (4L:20D), short days (8L:16D), equinox (12L:12L), and extreme long days (20L:4D). Since changes in life history strategy are likely to involve changes in energy utilization (Ananthasubramaniam et al 2015), overall metabolic rate was also investigated. Provided the inherently variable nature of life history and behavioral responses to stimuli, we repeated the photoperiod exposures in two temporally separated experiments on 17 October 2014 and 11 March 2015, hereafter referred to as Experiment 1 and Experiment 2, to assess the reproducibility of all measures and endpoints from one experiment to the next, and assessed if the two data sets could be combined for examination as one large dataset. In summary, 2 duplicate photoperiod experiments were conducted where each included 5 photoperiods x 3 exposure replicates. The present GEO dataset represents Experiment 2. In addition to life history endpoints, basic behavioral responses to photo-period were of interest; thus, instantaneous response to light as a stimulus where photo-taxis (“light oriented reactive swimming” Fraenkel et al 1961) was investigated in real-time light/dark preference assays and time series light acclimation assays. Lastly, an investigation of global-transcript expression was conducted to identify the genes and genetic pathways that were responsive to the five different, static photoperiod lengths and to establish potential relationships between affected genes/pathways and any observed changes in life history traits, metabolic rate and behavioral responses.
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| Contributor(s) |
Kennedy AJ, Gust KA, Laird JG, Wilbanks MS, Guan X, Melby NL, Burgoon LD, Kjelland ME, Swannack TM |
| Citation(s) |
31486145 |
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| Submission date |
Jul 17, 2018 |
| Last update date |
Oct 22, 2019 |
| Contact name |
Kurt A Gust |
| E-mail(s) |
kurt.a.gust@usace.army.mil
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| Phone |
601-634-3593
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| Organization name |
US Army ERDC
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| Department |
Environmental Laboratory
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| Lab |
Environmental Genomics and Systems Biology Team
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| Street address |
3909 Halls Ferry Rd.
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| City |
Vicksburg |
| State/province |
MS |
| ZIP/Postal code |
39180 |
| Country |
USA |
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| Platforms (1) |
| GPL16579 |
Agilent-023710 Daphnia magna 8x15k oligonucleotide array [Probe Name version] |
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| Samples (30)
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| GSM3289806 |
Exp-2_4L:20D_ExposureRep-2_SubSample-B |
| GSM3289807 |
Exp-2_4L:20D_ExposureRep-3_SubSample-A |
| GSM3289808 |
Exp-2_4L:20D_ExposureRep-3_SubSample-B |
| GSM3289809 |
Exp-2_8L:16D_ExposureRep-1_SubSample-A |
| GSM3289810 |
Exp-2_8L:16D_ExposureRep-1_SubSample-B |
| GSM3289811 |
Exp-2_8L:16D_ExposureRep-2_SubSample-A |
| GSM3289812 |
Exp-2_8L:16D_ExposureRep-2_SubSample-B |
| GSM3289813 |
Exp-2_8L:16D_ExposureRep-3_SubSample-A |
| GSM3289814 |
Exp-2_8L:16D_ExposureRep-3_SubSample-B |
| GSM3289815 |
Exp-2_12L:12D_ExposureRep-1_SubSample-A |
| GSM3289816 |
Exp-2_12L:12D_ExposureRep-1_SubSample-B |
| GSM3289817 |
Exp-2_12L:12D_ExposureRep-2_SubSample-A |
| GSM3289818 |
Exp-2_12L:12D_ExposureRep-2_SubSample-B |
| GSM3289819 |
Exp-2_12L:12D_ExposureRep-3_SubSample-A |
| GSM3289820 |
Exp-2_12L:12D_ExposureRep-3_SubSample-B |
| GSM3289821 |
Exp-2_16L:08D_ExposureRep-1_SubSample-A |
| GSM3289822 |
Exp-2_16L:08D_ExposureRep-1_SubSample-B |
| GSM3289823 |
Exp-2_16L:08D_ExposureRep-2_SubSample-A |
| GSM3289824 |
Exp-2_16L:08D_ExposureRep-2_SubSample-B |
| GSM3289825 |
Exp-2_16L:08D_ExposureRep-3_SubSample-A |
| GSM3289826 |
Exp-2_16L:08D_ExposureRep-3_SubSample-B |
| GSM3289827 |
Exp-2_20L:04D_ExposureRep-1_SubSample-A |
| GSM3289828 |
Exp-2_20L:04D_ExposureRep-1_SubSample-B |
| GSM3289829 |
Exp-2_20L:04D_ExposureRep-2_SubSample-A |
| GSM3289830 |
Exp-2_20L:04D_ExposureRep-2_SubSample-B |
| GSM3289831 |
Exp-2_20L:04D_ExposureRep-3_SubSample-A |
| GSM3289832 |
Exp-2_20L:04D_ExposureRep-3_SubSample-B |
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| This SubSeries is part of SuperSeries: |
| GSE117244 |
Mechanistic Evaluation of Daphnia magna’s Behavioral and Life History Responses to Photoperiod |
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| Relations |
| BioProject |
PRJNA481523 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE117243_RAW.tar |
22.6 Mb |
(http)(custom) |
TAR (of TXT) |
| Processed data included within Sample table |
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