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Qu M, Zhang Y, Gao Z, Zhang Z, Liu Y, Wan S, Wang X, Yu H, Zhang H, Liu Y, Schneider R, Meyer A, Lin Q. The genetic basis of the leafy seadragon's unique camouflage morphology and avenues for its efficient conservation derived from habitat modeling. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2317-6. [PMID: 37204606 DOI: 10.1007/s11427-022-2317-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/03/2023] [Indexed: 05/20/2023]
Abstract
The leafy seadragon certainly is among evolution's most "beautiful and wonderful" species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat. However, limited information is known about the genetic basis of its phenotypes and conspicuous camouflage. Here, we revealed genomic signatures of rapid evolution and positive selection in core genes related to its camouflage, which allowed us to predict population dynamics for this species. Comparative genomic analysis revealed that seadragons have the smallest olfactory repertoires among all ray-finned fishes, suggesting adaptations to the highly specialized habitat. Other positively selected and rapidly evolving genes that serve in bone development and coloration are highly expressed in the leaf-like appendages, supporting a recent adaptive shift in camouflage appendage formation. Knock-out of bmp6 results in dysplastic intermuscular bones with a significantly reduced number in zebrafish, implying its important function in bone formation. Global climate change-induced loss of seagrass beds now severely threatens the continued existence of this enigmatic species. The leafy seadragon has a historically small population size likely due to its specific habitat requirements that further exacerbate its vulnerability to climate change. Therefore, taking climate change-induced range shifts into account while developing future protection strategies.
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Affiliation(s)
- Meng Qu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yingyi Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zexia Gao
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhixin Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
- Global Ocean and Climate Research Center, South China Sea Institute of Oceanology, Guangzhou, 510301, China
| | - Yali Liu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shiming Wan
- College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xin Wang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
| | - Haiyan Yu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
| | - Huixian Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
| | - Yuhong Liu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China
| | - Ralf Schneider
- Marine Evolutionary Ecology, Zoological Institute, Kiel University, 24118, Kiel, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany.
| | - Qiang Lin
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Southern Marine Science and Engineering Guangdong Laboratory (GML, Guangzhou), Guangzhou, 511458, China.
- Sanya Institute of Oceanology, SCSIO, Sanya, 572000, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Gupta R, Mittal A, Agrawal V, Gupta S, Gupta K, Jain RR, Garg P, Mohanty SK, Sogani R, Chhabra HS, Gautam V, Mishra T, Sengupta D, Ahuja G. OdoriFy: A conglomerate of artificial intelligence-driven prediction engines for olfactory decoding. J Biol Chem 2021; 297:100956. [PMID: 34265305 PMCID: PMC8342790 DOI: 10.1016/j.jbc.2021.100956] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/24/2021] [Accepted: 07/09/2021] [Indexed: 12/01/2022] Open
Abstract
The molecular mechanisms of olfaction, or the sense of smell, are relatively underexplored compared with other sensory systems, primarily because of its underlying molecular complexity and the limited availability of dedicated predictive computational tools. Odorant receptors (ORs) allow the detection and discrimination of a myriad of odorant molecules and therefore mediate the first step of the olfactory signaling cascade. To date, odorant (or agonist) information for the majority of these receptors is still unknown, limiting our understanding of their functional relevance in odor-induced behavioral responses. In this study, we introduce OdoriFy, a Web server featuring powerful deep neural network–based prediction engines. OdoriFy enables (1) identification of odorant molecules for wildtype or mutant human ORs (Odor Finder); (2) classification of user-provided chemicals as odorants/nonodorants (Odorant Predictor); (3) identification of responsive ORs for a query odorant (OR Finder); and (4) interaction validation using Odorant–OR Pair Analysis. In addition, OdoriFy provides the rationale behind every prediction it makes by leveraging explainable artificial intelligence. This module highlights the basis of the prediction of odorants/nonodorants at atomic resolution and for the ORs at amino acid levels. A key distinguishing feature of OdoriFy is that it is built on a comprehensive repertoire of manually curated information of human ORs with their known agonists and nonagonists, making it a highly interactive and resource-enriched Web server. Moreover, comparative analysis of OdoriFy predictions with an alternative structure-based ligand interaction method revealed comparable results. OdoriFy is available freely as a web service at https://odorify.ahujalab.iiitd.edu.in/olfy/.
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Affiliation(s)
- Ria Gupta
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Aayushi Mittal
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Vishesh Agrawal
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Sushant Gupta
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Krishan Gupta
- Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Rishi Raj Jain
- Department of Computer Science and Design, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Prakriti Garg
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Sanjay Kumar Mohanty
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Riya Sogani
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Harshit Singh Chhabra
- Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Vishakha Gautam
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India
| | - Tripti Mishra
- Pathfinder Research and Training Foundation, Greater Noida, Uttar Pradesh, India
| | - Debarka Sengupta
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India; Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India; Centre for Artificial Intelligence, Indraprastha Institute of Information Technology, New Delhi, India; Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Gaurav Ahuja
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), New Delhi, India.
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Kalra S, Mittal A, Bajoria M, Mishra T, Maryam S, Sengupta D, Ahuja G. Challenges and possible solutions for decoding extranasal olfactory receptors. FEBS J 2020; 288:4230-4241. [PMID: 33085840 DOI: 10.1111/febs.15606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/29/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022]
Abstract
Olfactory receptors are primarily known to be expressed in the olfactory epithelium of the nasal cavity and therefore assist in odor perception. With the advent of high-throughput omics technologies such as tissue microarray or RNA sequencing, a large number of olfactory receptors have been reported to be expressed in the nonolfactory tissues. Although these technologies uncovered the expression of these olfactory receptors in the nonchemosensory tissues, unfortunately, they failed to reveal the information about their cell type of origin. Accurate characterization of the cell types should be the first step towards devising cell type-specific assays for their functional evaluation. Single-cell RNA-sequencing technology resolved some of these apparent limitations and opened new means to interrogate the expression of these extranasal olfactory receptors at the single-cell resolution. Moreover, the availability of large-scale, multi-organ/species single-cell expression atlases offer ample resources for the systematic reannotation of these receptors in a cell type-specific manner. In this Viewpoint article, we discuss some of the technical limitations that impede the in-depth understanding of these extranasal olfactory receptors, with a special focus on odorant receptors. Moreover, we also propose a list of single cell-based omics technologies that could further promulgate the opportunity to decipher the regulatory network that drives the odorant receptors expression at atypical locations.
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Affiliation(s)
- Siddhant Kalra
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India
| | - Aayushi Mittal
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India
| | - Manisha Bajoria
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India
| | - Tripti Mishra
- Pathfinder Research and Training Foundation, Greater Noida, India
| | - Sidrah Maryam
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India
| | - Debarka Sengupta
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India.,Department of Computer Science and Engineering, Indraprastha Institute of Information Technology, New Delhi, India, India.,Centre for Artificial Intelligence, Indraprastha Institute of Information Technology, New Delhi, India.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Gaurav Ahuja
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi, India, India
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Kalra S, Mittal A, Gupta K, Singhal V, Gupta A, Mishra T, Naidu S, Sengupta D, Ahuja G. Analysis of single-cell transcriptomes links enrichment of olfactory receptors with cancer cell differentiation status and prognosis. Commun Biol 2020; 3:506. [PMID: 32917933 PMCID: PMC7486295 DOI: 10.1038/s42003-020-01232-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022] Open
Abstract
Ectopically expressed olfactory receptors (ORs) have been linked with multiple clinically-relevant physiological processes. Previously used tissue-level expression estimation largely shadowed the potential role of ORs due to their overall low expression levels. Even after the introduction of the single-cell transcriptomics, a comprehensive delineation of expression dynamics of ORs in tumors remained unexplored. Our targeted investigation into single malignant cells revealed a complex landscape of combinatorial OR expression events. We observed differentiation-dependent decline in expressed OR counts per cell as well as their expression intensities in malignant cells. Further, we constructed expression signatures based on a large spectrum of ORs and tracked their enrichment in bulk expression profiles of tumor samples from The Cancer Genome Atlas (TCGA). TCGA tumor samples stratified based on OR-centric signatures exhibited divergent survival probabilities. In summary, our comprehensive analysis positions ORs at the cross-road of tumor cell differentiation status and cancer prognosis.
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Affiliation(s)
- Siddhant Kalra
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India
| | - Aayushi Mittal
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India
| | - Krishan Gupta
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India.,Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India
| | - Vrinda Singhal
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India
| | - Anku Gupta
- Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India
| | - Tripti Mishra
- Pathfinder Research and Training Foundation, 30/7 and 8, Knowledge Park III, Greater Noida, Uttar Pradesh, 201308, India
| | - Srivatsava Naidu
- Center for Biomedical Engineering, Indian Institute of Technology Ropar, Bara Phool, Birla Seed Farms, Rupnagar, Punjab, 140001, India
| | - Debarka Sengupta
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India. .,Department of Computer Science and Engineering, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India. .,Centre for Artificial Intelligence, Indraprastha Institute of Information Technology, Okhla Phase III, New Delhi, 110020, India. .,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
| | - Gaurav Ahuja
- Department of Computational Biology, Indraprastha Institute of Information Technology-Delhi (IIIT-Delhi), Okhla, Phase III, New Delhi, 110020, India.
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5
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Porter BA, Mueller T. The Zebrafish Amygdaloid Complex - Functional Ground Plan, Molecular Delineation, and Everted Topology. Front Neurosci 2020; 14:608. [PMID: 32765204 PMCID: PMC7378821 DOI: 10.3389/fnins.2020.00608] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 05/18/2020] [Indexed: 12/19/2022] Open
Abstract
In mammals and other tetrapods, a multinuclear forebrain structure, called the amygdala, forms the neuroregulatory core essential for emotion, cognition, and social behavior. Currently, higher circuits of affective behavior in anamniote non-tetrapod vertebrates (“fishes”) are poorly understood, preventing a comprehensive understanding of amygdala evolution. Through molecular characterization and evolutionary-developmental considerations, we delineated the complex amygdala ground plan of zebrafish, whose everted telencephalon has made comparisons to the evaginated forebrains of tetrapods challenging. In this radical paradigm, thirteen telencephalic territories constitute the zebrafish amygdaloid complex and each territory is distinguished by conserved molecular properties and structure-functional relationships with other amygdaloid structures. Central to our paradigm, the study identifies the teleostean amygdaloid nucleus of the lateral olfactory tract (nLOT), an olfactory integrative structure that links dopaminergic telencephalic groups to the amygdala alongside redefining the putative zebrafish olfactory pallium (“Dp”). Molecular characteristics such as the distribution of substance P and the calcium-binding proteins parvalbumin (PV) and calretinin (CR) indicate, that the zebrafish extended centromedial (autonomic and reproductive) amygdala is predominantly located in the GABAergic and isl1-negative territory. Like in tetrapods, medial amygdaloid (MeA) nuclei are defined by the presence of substance P immunoreactive fibers and calretinin-positive neurons, whereas central amygdaloid (CeA) nuclei lack these characteristics. A detailed comparison of lhx5-driven and vGLut2a-driven GFP in transgenic reporter lines revealed ancestral topological relationships between the thalamic eminence (EmT), the medial amygdala (MeA), the nLOT, and the integrative olfactory pallium. Thus, the study explains how the zebrafish amygdala and the complexly everted telencephalon topologically relate to the corresponding structures in mammals indicating that an elaborate amygdala ground plan evolved early in vertebrates, in a common ancestor of teleosts and tetrapods.
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Affiliation(s)
- Baylee A Porter
- Division of Biology, Kansas State University, Manhattan, KS, United States.,Department of Biochemistry and Molecular Biology, Department of Urology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Thomas Mueller
- Division of Biology, Kansas State University, Manhattan, KS, United States
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6
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Yang L, Jiang H, Chen J, Lei Y, Sun N, Lv W, Near TJ, He S. Comparative Genomics Reveals Accelerated Evolution of Fright Reaction Genes in Ostariophysan Fishes. Front Genet 2019; 10:1283. [PMID: 31921316 PMCID: PMC6936194 DOI: 10.3389/fgene.2019.01283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/21/2019] [Indexed: 11/13/2022] Open
Abstract
The ostariophysian fishes are the most species-rich clade in freshwaters. This diversification has been suggested to be associated with the fright reaction presented in most ostariophysians. However, the genetic forces that underlie fright reaction remains poorly understood. In the present study, through integrating behavioral, physiological, transcriptomic, and evolutionary genomic analyses, we found that the fright reaction has a broad impact on zebrafish at multiple levels, including changes in swimming behaviors, cortisol levels, and gene expression patterns. In total, 1,555 and 1,599 differentially expressed genes were identified in olfactory mucosae and brain of zebrafish, respectively, with a greater number upregulated after the fright reaction. Functional annotation showed that response to stress and signal transduction were strongly represented, which is directly associated with the fright reaction. These differentially expressed genes were shown to be evolved accelerated under the influence of positive selection, indicating that protein-coding evolution has played a major role in fright reaction. We found the basal vomeronasal type 2 receptors (v2r) gene, v2rl1, displayed significantly decrease expression after fright reaction, which suggests that v2rs may be important to detect the alarm substance and induce the fright reaction. Collectively, based on our transcriptome and evolutionary genomics analyses, we suggest that transcriptional plasticity of gene may play an important role in fright reaction in ostariophysian fishes.
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Affiliation(s)
- Liandong Yang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Haifeng Jiang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Juan Chen
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yi Lei
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ning Sun
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wenqi Lv
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Thomas J Near
- Department of Ecology and Evolutionary Biology and Peabody Museum of Natural History, Yale University, New Haven, CT, United States
| | - Shunping He
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
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7
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Madsen SS, Winther SST, Bollinger RJ, Steiner U, Larsen MH. Differential expression of olfactory genes in Atlantic salmon ( Salmo salar) during the parr-smolt transformation. Ecol Evol 2019; 9:14085-14100. [PMID: 31938505 PMCID: PMC6953650 DOI: 10.1002/ece3.5845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 02/05/2023] Open
Abstract
The anadromous salmon life cycle includes two migratory events, downstream smolt migration and adult homing migration, during which they must navigate with high precision. During homing migration, olfactory cues are used for navigation in coastal and freshwater areas, and studies have suggested that the parr-smolt transformation has a sensitive period for imprinting. Accordingly, we hypothesized that there would be significant changes in gene expression in the olfactory epithelium specifically related to smoltification and sampled olfactory rosettes from hatchery-reared upper growth modal juvenile Atlantic salmon at 3-week intervals from January to June, using lower growth modal nonsmolting siblings as controls. A suite of olfactory receptors and receptor-specific proteins involved in functional aspects of olfaction and peripheral odor memorization was analyzed by qPCR. Gene expression in juveniles was compared with mature adult salmon of the same genetic strain caught in the river Gudenaa. All mRNAs displayed significant variation over time in both modal groups. Furthermore, five receptor genes (olfc13.1, olfc15.1, sorb, ora2, and asor1) and four olfactory-specific genes (soig, ependymin, gst, and omp2) were differentially regulated between modal groups, suggesting altered olfactory function during smoltification. Several genes were differentially regulated in mature salmon compared with juveniles, suggesting that homing and odor recollection involve a different set of genes than during imprinting. Thyroid hormone receptors thrα and thrβ mRNAs were elevated during smolting, suggesting increased sensitivity to thyroid hormones. Treatment of presmolts with triiodothyronine in vivo and ex vivo had, however, only subtle effects on the investigated olfactory targets, questioning the hypothesis that thyroid hormones directly regulate gene expression in the olfactory epithelium.
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Affiliation(s)
| | | | | | - Ulrich Steiner
- Department of BiologyUniversity of Southern DenmarkOdenseDenmark
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Calvo-Ochoa E, Byrd-Jacobs CA. The Olfactory System of Zebrafish as a Model for the Study of Neurotoxicity and Injury: Implications for Neuroplasticity and Disease. Int J Mol Sci 2019; 20:ijms20071639. [PMID: 30986990 PMCID: PMC6480214 DOI: 10.3390/ijms20071639] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/26/2019] [Accepted: 03/29/2019] [Indexed: 12/30/2022] Open
Abstract
The olfactory system, composed of the olfactory organs and the olfactory bulb, allows organisms to interact with their environment and through the detection of odor signals. Olfaction mediates behaviors pivotal for survival, such as feeding, mating, social behavior, and danger assessment. The olfactory organs are directly exposed to the milieu, and thus are particularly vulnerable to damage by environmental pollutants and toxicants, such as heavy metals, pesticides, and surfactants, among others. Given the widespread occurrence of olfactory toxicants, there is a pressing need to understand the effects of these harmful compounds on olfactory function. Zebrafish (Danio rerio) is a valuable model for studying human physiology, disease, and toxicity. Additionally, the anatomical components of the zebrafish olfactory system are similar to those of other vertebrates, and they present a remarkable degree of regeneration and neuroplasticity, making it an ideal model for the study of regeneration, reorganization and repair mechanisms following olfactory toxicant exposure. In this review, we focus on (1) the anatomical, morphological, and functional organization of the olfactory system of zebrafish; (2) the adverse effects of olfactory toxicants and injury to the olfactory organ; and (3) remodeling and repair neuroplasticity mechanisms following injury and degeneration by olfactory toxicant exposure.
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Affiliation(s)
- Erika Calvo-Ochoa
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008-5410, USA.
| | - Christine A Byrd-Jacobs
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008-5410, USA.
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