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Xiao X, Mei Y, Deng W, Zou G, Hou H, Ji X. Electric Eel Biomimetics for Energy Storage and Conversion. SMALL METHODS 2024; 8:e2201435. [PMID: 36840652 DOI: 10.1002/smtd.202201435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The electric eel is known as the most powerful creature to generate electricity with a discharge voltage up to 860 V and peak current up to 1 A. These surprising properties are the results of billions of years of evolution on the electrical biological structure and bulk, and now have triggered great research interest in electric eel biomimetics for designing innovated configurations and components of energy storage and conversion devices. In this review, first, the bioelectrical behavior of electric eels is surveyed, followed by the physiological structure to reveal the discharge characteristics and principles of electric organs and electrocytes. Additionally, underlying electrochemical mechanisms and models for calculating the potential and current of electrocytes are presented. Central to this review is the recent progress of electric-eel-inspired innovations and applications for energy storage and conversion, particularly including novel power sources, triboelectric nanogenerators, and nanochannel ion-selective membranes for salinity gradient energy harvesting. Finally, insights on the challenges at the moment and the perspectives on the future research prospects are critically compiled. It is suggested that energy-related electric eel biomimetics will greatly boost the development of next-generation high performance, green, and functional electronics.
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Affiliation(s)
- Xiangting Xiao
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Yu Mei
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Wentao Deng
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Guoqiang Zou
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Hongshuai Hou
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
| | - Xiaobo Ji
- State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China
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El-Mansi AA, Rady AM, Ibrahim EH, ElBealy E. Cellular patterning and cyto-architectural organization of the skin of electric catfish (Malapterurus electricus, Siluriformes) with a particular emphasis on its ampullary electroreceptor. ZOOLOGY 2024; 163:126159. [PMID: 38471427 DOI: 10.1016/j.zool.2024.126159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 02/04/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024]
Abstract
The functional morphology of the skin of Malapteruridae is presumably evolved to cope with a diversified range of ambient physiological, environmental, and behavioral conditions. Herein, we firstly characterized the microstructures and intriguing patterning of the skin of twelve adult electric catfish (Malapterurus electricus, Malapteruridae) using histological, histochemical, immunofluorescent, and ELISA standard methodology. The skin comprises three sequentially-oriented layers: the epidermis, dermis, and hypodermis with a significantly increased thickness of the former. The epidermis contains four types of cells: the surface epithelial cells, mucous cells, granular cells, and club cells. We defined distinctive ampullary electroreceptors in the outer epidermis that possess flask-shaped sensory crypt containing electroreceptor cells together with vertical collagen rods. Dermis and hypodermis are composed of connective tissue; however, the former is much more coarse and dense with comparable reactivity for Masson-Goldner trichrome (MT). Placing our data in the context of the limited body of previous work, we showed subtle changes in the expression of mucin subunits together with cytoskeletal fractions of collagens, myosin, F-actin, keratins, and tubulins. Taken as a whole, our results convincingly showed that the skin of M. electricus shares some structural similarities to other Siluriformes, however, it has some functional modifications that are implicated in protection, defense, and foraging behavior.
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Affiliation(s)
- Ahmed A El-Mansi
- Biology Dept., Faculty of Science, King Khalid University, Abha, 61421, Saudi Arabia.
| | - Ahmed M Rady
- Biology Dept., Faculty of Science, King Saud University, Riyadh, Saudi Arabia
| | - Esam H Ibrahim
- Biology Dept., Faculty of Science, King Khalid University, Abha, 61421, Saudi Arabia
| | - Eman ElBealy
- Biology Dept., Faculty of Science, King Khalid University, Abha, 61421, Saudi Arabia
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3
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Liu M, Song Y, Zhang S, Yu L, Yuan Z, Yang H, Zhang M, Zhou Z, Seim I, Liu S, Fan G, Yang H. A chromosome-level genome of electric catfish ( Malapterurus electricus) provided new insights into order Siluriformes evolution. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:1-14. [PMID: 38433969 PMCID: PMC10901758 DOI: 10.1007/s42995-023-00197-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 09/22/2023] [Indexed: 03/05/2024]
Abstract
The electric catfish (Malapterurus electricus), belonging to the family Malapteruridae, order Siluriformes (Actinopterygii: Ostariophysi), is one of the six branches that has independently evolved electrical organs. We assembled a 796.75 Mb M. electricus genome and anchored 88.72% sequences into 28 chromosomes. Gene family analysis revealed 295 expanded gene families that were enriched on functions related to glutamate receptors. Convergent evolutionary analyses of electric organs among different lineage of electric fishes further revealed that the coding gene of rho guanine nucleotide exchange factor 4-like (arhgef4), which is associated with G-protein coupled receptor (GPCR) signaling pathway, underwent adaptive parallel evolution. Gene identification suggests visual degradation in catfishes, and an important role for taste in environmental adaptation. Our findings fill in the genomic data for a branch of electric fish and provide a relevant genetic basis for the adaptive evolution of Siluriformes. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00197-8.
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Affiliation(s)
- Meiru Liu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
- BGI-Shenzhen, Shenzhen, 518083 China
| | - Yue Song
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
- BGI-Shenzhen, Shenzhen, 518083 China
| | - Suyu Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
- BGI-Shenzhen, Shenzhen, 518083 China
| | - Lili Yu
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
| | - Zengbao Yuan
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
- BGI-Shenzhen, Shenzhen, 518083 China
| | - Hengjia Yang
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
| | - Mengqi Zhang
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
| | - Zhuocheng Zhou
- Professional Committee of Native Aquatic Organisms and Water Ecosystem of China Fisheries Association, Beijing, 100125 China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, 210023 China
| | - Shanshan Liu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Guangyi Fan
- BGI-Qingdao, BGI-Shenzhen, Qingdao, 266555 China
- BGI-Shenzhen, Shenzhen, 518083 China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083 China
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen, 518083 China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083 China
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Cheng F, Dennis AB, Osuoha JI, Canitz J, Kirschbaum F, Tiedemann R. A new genome assembly of an African weakly electric fish (Campylomormyrus compressirostris, Mormyridae) indicates rapid gene family evolution in Osteoglossomorpha. BMC Genomics 2023; 24:129. [PMID: 36941548 PMCID: PMC10029256 DOI: 10.1186/s12864-023-09196-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/20/2023] [Indexed: 03/23/2023] Open
Abstract
BACKGROUND Teleost fishes comprise more than half of the vertebrate species. Within teleosts, most phylogenies consider the split between Osteoglossomorpha and Euteleosteomorpha/Otomorpha as basal, preceded only by the derivation of the most primitive group of teleosts, the Elopomorpha. While Osteoglossomorpha are generally species poor, the taxon contains the African weakly electric fish (Mormyroidei), which have radiated into numerous species. Within the mormyrids, the genus Campylomormyrus is mostly endemic to the Congo Basin. Campylomormyrus serves as a model to understand mechanisms of adaptive radiation and ecological speciation, especially with regard to its highly diverse species-specific electric organ discharges (EOD). Currently, there are few well-annotated genomes available for electric fish in general and mormyrids in particular. Our study aims at producing a high-quality genome assembly and to use this to examine genome evolution in relation to other teleosts. This will facilitate further understanding of the evolution of the osteoglossomorpha fish in general and of electric fish in particular. RESULTS A high-quality weakly electric fish (C. compressirostris) genome was produced from a single individual with a genome size of 862 Mb, consisting of 1,497 contigs with an N50 of 1,399 kb and a GC-content of 43.69%. Gene predictions identified 34,492 protein-coding genes, which is a higher number than in the two other available Osteoglossomorpha genomes of Paramormyrops kingsleyae and Scleropages formosus. A Computational Analysis of gene Family Evolution (CAFE5) comparing 33 teleost fish genomes suggests an overall faster gene family turnover rate in Osteoglossomorpha than in Otomorpha and Euteleosteomorpha. Moreover, the ratios of expanded/contracted gene family numbers in Osteoglossomorpha are significantly higher than in the other two taxa, except for species that had undergone an additional genome duplication (Cyprinus carpio and Oncorhynchus mykiss). As potassium channel proteins are hypothesized to play a key role in EOD diversity among species, we put a special focus on them, and manually curated 16 Kv1 genes. We identified a tandem duplication in the KCNA7a gene in the genome of C. compressirostris. CONCLUSIONS We present the fourth genome of an electric fish and the third well-annotated genome for Osteoglossomorpha, enabling us to compare gene family evolution among major teleost lineages. Osteoglossomorpha appear to exhibit rapid gene family evolution, with more gene family expansions than contractions. The curated Kv1 gene family showed seven gene clusters, which is more than in other analyzed fish genomes outside Osteoglossomorpha. The KCNA7a, encoding for a potassium channel central for EOD production and modulation, is tandemly duplicated which may related to the diverse EOD observed among Campylomormyrus species.
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Affiliation(s)
- Feng Cheng
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Alice B Dennis
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Laboratory of Adaptive Evolution and Genomics, Research Unit of Environmental and Evolutionary Biology, Institute of Life, Earth & Environnment, University of Namur, Namur, Belgium
| | - Josephine Ijeoma Osuoha
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Julia Canitz
- Senckenberg German Entomological Institute, Müncheberg, Germany
| | - Frank Kirschbaum
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Department of Crop and Animal Science, Faculty of Life Sciences, Humboldt University, Berlin, Germany
| | - Ralph Tiedemann
- Unit of Evolutionary Biology and Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
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LaPotin S, Swartz ME, Luecke DM, Constantinou SJ, Gallant JR, Eberhart JK, Zakon HH. Divergent cis-regulatory evolution underlies the convergent loss of sodium channel expression in electric fish. SCIENCE ADVANCES 2022; 8:eabm2970. [PMID: 35648851 PMCID: PMC9159570 DOI: 10.1126/sciadv.abm2970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
South American and African weakly electric fish independently evolved electric organs from muscle. In both groups, a voltage-gated sodium channel gene independently lost expression from muscle and gained it in the electric organ, allowing the channel to become specialized for generating electric signals. It is unknown how this voltage-gated sodium channel gene is targeted to muscle in any vertebrate. We describe an enhancer that selectively targets sodium channel expression to muscle. Next, we demonstrate how the loss of this enhancer, but not trans-activating factors, drove the loss of sodium channel gene expression from muscle in South American electric fish. While this enhancer is also altered in African electric fish, key transcription factor binding sites and enhancer activity are retained, suggesting that the convergent loss of sodium channel expression from muscle in these two electric fish lineages occurred via different processes.
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Affiliation(s)
- Sarah LaPotin
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
| | - Mary E. Swartz
- Department of Molecular Biosciences, The University of Texas, Austin, TX 78712, USA
| | - David M. Luecke
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Savvas J. Constantinou
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Jason R. Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - Johann K. Eberhart
- Department of Molecular Biosciences, The University of Texas, Austin, TX 78712, USA
| | - Harold H. Zakon
- Department of Neuroscience, The University of Texas, Austin, TX 78712, USA
- Department of Integrative Biology, The University of Texas, Austin, TX 78712, USA
- Corresponding author.
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6
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Beck EA, Healey HM, Small CM, Currey MC, Desvignes T, Cresko WA, Postlethwait JH. Advancing human disease research with fish evolutionary mutant models. Trends Genet 2022; 38:22-44. [PMID: 34334238 PMCID: PMC8678158 DOI: 10.1016/j.tig.2021.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 01/03/2023]
Abstract
Model organism research is essential to understand disease mechanisms. However, laboratory-induced genetic models can lack genetic variation and often fail to mimic the spectrum of disease severity. Evolutionary mutant models (EMMs) are species with evolved phenotypes that mimic human disease. EMMs complement traditional laboratory models by providing unique avenues to study gene-by-environment interactions, modular mutations in noncoding regions, and their evolved compensations. EMMs have improved our understanding of complex diseases, including cancer, diabetes, and aging, and illuminated mechanisms in many organs. Rapid advancements of sequencing and genome-editing technologies have catapulted the utility of EMMs, particularly in fish. Fish are the most diverse group of vertebrates, exhibiting a kaleidoscope of specialized phenotypes, many that would be pathogenic in humans but are adaptive in the species' specialized habitat. Importantly, evolved compensations can suggest avenues for novel disease therapies. This review summarizes current research using fish EMMs to advance our understanding of human disease.
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Affiliation(s)
- Emily A Beck
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA.
| | - Hope M Healey
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Clayton M Small
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Mark C Currey
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Thomas Desvignes
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - William A Cresko
- Data Science, University of Oregon, Eugene, OR 97403, USA; Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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7
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Abstract
The electric eel is a unique species that has evolved three electric organs. Since the 1950s, electric eels have generally been assumed to use these three organs to generate two forms of electric organ discharge (EOD): high-voltage EOD for predation and defense and low-voltage EOD for electrolocation and communication. However, why electric eels evolved three electric organs to generate two forms of EOD and how these three organs work together to generate these two forms of EOD have not been clear until now. Here, we present the third form of independent EOD of electric eels: middle-voltage EOD. We suggest that every form of EOD is generated by one electric organ independently and reveal the typical discharge order of the three electric organs. We also discuss hybrid EODs, which are combinations of these three independent EODs. This new finding indicates that the electric eel discharge behavior and physiology and the evolutionary purpose of the three electric organs are more complex than previously assumed. The purpose of the middle-voltage EOD still requires clarification.
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8
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Li L, Liu D, Liu A, Li J, Wang H, Zhou J. Genomic Survey of Tyrosine Kinases Repertoire in Electrophorus electricus With an Emphasis on Evolutionary Conservation and Diversification. Evol Bioinform Online 2020; 16:1176934320922519. [PMID: 32546936 PMCID: PMC7249569 DOI: 10.1177/1176934320922519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/07/2020] [Indexed: 12/05/2022] Open
Abstract
Tyrosine kinases (TKs) play key roles in the regulation of multicellularity in
organisms and involved primarily in cell growth, differentiation, and
cell-to-cell communication. Genome-wide characterization of TKs has been
conducted in many metazoans; however, systematic information regarding this
superfamily in Electrophorus electricus (electric eel) is still
lacking. In this study, we identified 114 TK genes in the E
electricus genome and investigated their evolution, molecular
features, and domain architecture using phylogenetic profiling to gain a better
understanding of their similarities and specificity. Our results suggested that
the electric eel TK (EeTK) repertoire was shaped by whole-genome duplications
(WGDs) and tandem duplication events. Compared with other vertebrate TKs, gene
members in Jak, Src, and EGFR subfamily duplicated specifically, but with
members lost in Eph, Axl, and Ack subfamily in electric eel. We also conducted
an exhaustive survey of TK genes in genomic databases, identifying 1674 TK
proteins in 31 representative species covering all the main metazoan lineages.
Extensive evolutionary analysis indicated that TK repertoire in vertebrates
tended to be remarkably conserved, but the gene members in each subfamily were
very variable. Comparative expression profile analysis showed that electric
organ tissues and muscle shared a similar pattern with specific highly expressed
TKs (ie, epha7, musk, jak1, and pdgfra), suggesting that regulation of TKs might
play an important role in specifying an electric organ identity from its muscle
precursor. We further identified TK genes exhibiting tissue-specific expression
patterns, indicating that members in TKs participated in subfunctionalization
representing an evolutionary divergence required for the performance of
different tissues. This work generates valuable information for further gene
function analysis and identifying candidate TK genes reflecting their unique
tissue-function specializations in electric eel.
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Affiliation(s)
- Ling Li
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Dangyun Liu
- Department of Central Laboratory, The Affiliated Huaian No.1 People's Hospital, Nanjing Medical University, Huai'an, P.R. China
| | - Ake Liu
- Faculty of Biological Science and Technology, Changzhi University, Changzhi, P.R. China
| | - Jingquan Li
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Hui Wang
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China
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Abstract
Neuroscience has a long, rich history in embracing unusual animals for research. Over the past several decades, there has been a technology-driven bottleneck in the species used for neuroscience research. However, an oncoming wave of technologies applicable to many animals hold promise for enabling researchers to address challenging scientific questions that cannot be solved using traditional laboratory animals. Here, we discuss how leveraging the convergent evolution of physiological or behavioral phenotypes can empower research mapping genotype to phenotype interactions. We present two case studies using electric fish and poison frogs and discuss how comparative work can teach us about evolutionary constraint and flexibility at various levels of biological organization. We also offer advice on the potential and pitfalls of establishing novel model systems in neuroscience research. Finally, we end with a discussion on the use of charismatic animals in neuroscience research and their utility in public outreach. Overall, we argue that convergent evolution frameworks can help identify generalizable principles of neuroscience.
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Affiliation(s)
- Jason R Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
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10
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Liu A, He F, Zhou J, Zou Y, Su Z, Gu X. Comparative Transcriptome Analyses Reveal the Role of Conserved Function in Electric Organ Convergence Across Electric Fishes. Front Genet 2019; 10:664. [PMID: 31379927 PMCID: PMC6657706 DOI: 10.3389/fgene.2019.00664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/25/2019] [Indexed: 11/24/2022] Open
Abstract
The independent origins of multiple electric organs (EOs) of fish are fascinating examples of convergent evolution. However, comparative transcriptomics of different electric fish lineages are scarce. In this study, we found that the gene expression of EOs and skeletal muscles from three lineages (Mormyroidea, Siluriformes, and Gymnotiformes) tended to cluster together based on the species of origin, irrespective of the organ from which they are derived. A pairwise comparison of differentially expressed genes (DEGs) revealed that no less than half of shared DEGs exhibited parallel expression differentiation, indicating conserved directionality of differential expression either in or between lineages, but only a few shared DEGs were identified across all focal species. Nevertheless, the functional enrichment analysis of DEGs indicated that there were more parallel gene expression changes at the level of pathways and biological functions. Therefore, we may conclude that there is no parallel evolution of the entire transcriptomes of EOs among different lineages. Further, our results support the hypothesis that it is not different genes but conserved biological functions that play a crucial role in the convergence of complex phenotypes. This study provides insight into the genetic basis underlying the EO convergent evolution; however, more studies in different cases will be needed to demonstrate whether this pattern can be extended to other cases to derive a general rule for convergent evolution.
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Affiliation(s)
- Ake Liu
- Faculty of Biology Sciences and Technology, Changzhi University, Changzhi, China.,School of Life Sciences, Fudan University, Shanghai, China
| | - Funan He
- School of Life Sciences, Fudan University, Shanghai, China
| | - Jingqi Zhou
- School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yangyun Zou
- School of Life Sciences, Fudan University, Shanghai, China
| | - Zhixi Su
- School of Life Sciences, Fudan University, Shanghai, China.,Singlera Genomics Inc., Shanghai, China
| | - Xun Gu
- Department of GDC Biology, Iowa State University, Ames, IA, United States.,Fudan Human Phenome Institute, Shanghai, China
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11
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Traeger LL, Sabat G, Barrett-Wilt GA, Wells GB, Sussman MR. A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel. SCIENCE ADVANCES 2017; 3:e1700523. [PMID: 28695212 PMCID: PMC5498108 DOI: 10.1126/sciadv.1700523] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/19/2017] [Indexed: 05/22/2023]
Abstract
The electric eel (Electrophorus electricus) is unusual among electric fishes because it has three pairs of electric organs that serve multiple biological functions: For navigation and communication, it emits continuous pulses of weak electric discharge (<1 V), but for predation and defense, it intermittently emits lethal strong electric discharges (10 to 600 V). We hypothesized that these two electrogenic outputs have different energetic demands reflected by differences in their proteome and phosphoproteome. We report the use of isotope-assisted quantitative mass spectrometry to test this hypothesis. We observed novel phosphorylation sites in sodium transporters and identified a potassium channel with unique differences in protein concentration among the electric organs. In addition, we found transcription factors and protein kinases that show differential abundance in the strong versus weak electric organs. Our findings support the hypothesis that proteomic differences among electric organs underlie differences in energetic needs, reflecting a trade-off between generating weak voltages continuously and strong voltages intermittently.
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Affiliation(s)
- Lindsay L. Traeger
- Department of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Grzegorz Sabat
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Gregg B. Wells
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Michael R. Sussman
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Corresponding author.
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12
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Escobar-Camacho D, Ramos E, Martins C, Carleton KL. The opsin genes of amazonian cichlids. Mol Ecol 2017; 26:1343-1356. [PMID: 27997048 PMCID: PMC5342946 DOI: 10.1111/mec.13957] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/04/2016] [Accepted: 11/21/2016] [Indexed: 01/30/2023]
Abstract
Vision is a critical sense for organismal survival with visual sensitivities strongly shaped by the environment. Some freshwater fishes with a Gondwanan origin are distributed in both South American rivers including the Amazon and African rivers and lakes. These different habitats likely required adaptations to murky and clear environments. In this study, we compare the molecular basis of Amazonian and African cichlid fishes' visual systems. We used next-generation sequencing of genomes and retinal transcriptomes to examine three Amazonian cichlid species. Genome assemblies revealed six cone opsin classes (SWS1, SWS2B, SWS2A, RH2B, RH2A and LWS) and rod opsin (RH1). However, the functionality of these genes varies across species with different pseudogenes found in different species. Our results support evidence of an RH2A gene duplication event that is shared across both cichlid groups, but which was probably followed by gene conversion. Transcriptome analyses show that Amazonian species mainly express three opsin classes (SWS2A, RH2A and LWS), which likely are a good match to the long-wavelength-oriented light environment of the Amazon basin. Furthermore, analysis of amino acid sequences suggests that the short-wavelength-sensitive genes (SWS2B, SWS2A) may be under selective pressures to shift their spectral properties to a longer-wavelength visual palette. Our results agree with the 'sensitivity hypothesis' where the light environment causes visual adaptation. Amazonian cichlid visual systems are likely adapting through gene expression, gene loss and possibly spectral tuning of opsin sequences. Such mechanisms may be shared across the Amazonian fish fauna.
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Affiliation(s)
| | - Erica Ramos
- Department of Morphology, Biosciences Institute, São Paulo State University, 18618-689 Botucatu, Brazil
| | - Cesar Martins
- Department of Morphology, Biosciences Institute, São Paulo State University, 18618-689 Botucatu, Brazil
| | - Karen L. Carleton
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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Tian R, Losilla M, Lu Y, Yang G, Zakon H. Molecular evolution of globin genes in Gymnotiform electric fishes: relation to hypoxia tolerance. BMC Evol Biol 2017; 17:51. [PMID: 28193153 PMCID: PMC5307702 DOI: 10.1186/s12862-017-0893-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 01/26/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nocturnally active gymnotiform weakly electric fish generate electric signals for communication and navigation, which can be energetically taxing. These fish mainly inhabit the Amazon basin, where some species prefer well-oxygenated waters and others live in oxygen-poor, stagnant habitats. The latter species show morphological, physiological, and behavioral adaptations for hypoxia-tolerance. However, there have been no studies of hypoxia tolerance on the molecular level. Globins are classic respiratory proteins. They function principally in oxygen-binding and -delivery in various tissues and organs. Here, we investigate the molecular evolution of alpha and beta hemoglobins, myoglobin, and neuroglobin in 12 gymnotiforms compared with other teleost fish. RESULTS The present study identified positively selected sites (PSS) on hemoglobin (Hb) and myoglobin (Mb) genes using different maximum likelihood (ML) methods; some PSS fall in structurally important protein regions. This evidence for the positive selection of globin genes suggests that the adaptive evolution of these genes has helped to enhance the capacity for oxygen storage and transport. Interestingly, a substitution of a Cys at a key site in the obligate air-breathing electric eel (Electrophorus electricus) is predicted to enhance oxygen storage of Mb and contribute to NO delivery during hypoxia. A parallel Cys substitution was also noted in an air-breathing African electric fish (Gymnarchus niloticus). Moreover, the expected pattern under normoxic conditions of high expression of myoglobin in heart and neuroglobin in the brain in two hypoxia-tolerant species suggests that the main effect of selection on these globin genes is on their sequence rather than their basal expression patterns. CONCLUSION Results indicate a clear signature of positive selection in the globin genes of most hypoxia-tolerant gymnotiform fishes, which are obligate or facultative air breathers. These findings highlight the critical role of globin genes in hypoxia tolerance evolution of Gymnotiform electric fishes.
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Affiliation(s)
- Ran Tian
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China
- Department of Integrative Biology, The University of Texas, Austin, TX, 78759, USA
| | - Mauricio Losilla
- Department of Integrative Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Ying Lu
- Department of Integrative Biology, The University of Texas, Austin, TX, 78759, USA
- Department of Neuroscience, The University of Texas, Austin, TX, 78759, USA
| | - Guang Yang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China.
| | - Harold Zakon
- Department of Integrative Biology, The University of Texas, Austin, TX, 78759, USA.
- Department of Neuroscience, The University of Texas, Austin, TX, 78759, USA.
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Pitchers WR, Constantinou SJ, Losilla M, Gallant JR. Electric fish genomics: Progress, prospects, and new tools for neuroethology. ACTA ACUST UNITED AC 2016; 110:259-272. [PMID: 27769923 DOI: 10.1016/j.jphysparis.2016.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/06/2016] [Accepted: 10/16/2016] [Indexed: 01/01/2023]
Abstract
Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.
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Affiliation(s)
- William R Pitchers
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
| | - Savvas J Constantinou
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Mauricio Losilla
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA
| | - Jason R Gallant
- Dept. of Integrative Biology, Michigan State University, 288 Farm Lane RM 203, East Lansing, MI 48824, USA.
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Pinch M, Güth R, Samanta MP, Chaidez A, Unguez GA. The myogenic electric organ of Sternopygus macrurus: a non-contractile tissue with a skeletal muscle transcriptome. PeerJ 2016; 4:e1828. [PMID: 27114860 PMCID: PMC4841239 DOI: 10.7717/peerj.1828] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 02/29/2016] [Indexed: 12/13/2022] Open
Abstract
In most electric fish species, the electric organ (EO) derives from striated muscle cells that suppress many muscle properties. In the gymnotiform Sternopygus macrurus, mature electrocytes, the current-producing cells of the EO, do not contain sarcomeres, yet they continue to make some cytoskeletal and sarcomeric proteins and the muscle transcription factors (MTFs) that induce their expression. In order to more comprehensively examine the transcriptional regulation of genes associated with the formation and maintenance of the contractile sarcomere complex, results from expression analysis using qRT-PCR were informed by deep RNA sequencing of transcriptomes and miRNA compositions of muscle and EO tissues from adult S. macrurus. Our data show that: (1) components associated with the homeostasis of the sarcomere and sarcomere-sarcolemma linkage were transcribed in EO at levels similar to those in muscle; (2) MTF families associated with activation of the skeletal muscle program were not differentially expressed between these tissues; and (3) a set of microRNAs that are implicated in regulation of the muscle phenotype are enriched in EO. These data support the development of a unique and highly specialized non-contractile electrogenic cell that emerges from a striated phenotype and further differentiates with little modification in its transcript composition. This comprehensive analysis of parallel mRNA and miRNA profiles is not only a foundation for functional studies aimed at identifying mechanisms underlying the transcription-independent myogenic program in S. macrurus EO, but also has important implications to many vertebrate cell types that independently activate or suppress specific features of the skeletal muscle program.
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Affiliation(s)
- Matthew Pinch
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Robert Güth
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | | | - Alexander Chaidez
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Graciela A. Unguez
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
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Cross-tissue and cross-species analysis of gene expression in skeletal muscle and electric organ of African weakly-electric fish (Teleostei; Mormyridae). BMC Genomics 2015; 16:668. [PMID: 26335922 PMCID: PMC4558960 DOI: 10.1186/s12864-015-1858-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/18/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African weakly-electric fishes of the family Mormyridae are able to produce and perceive weak electric signals (typically less than one volt in amplitude) owing to the presence of a specialized, muscle-derived electric organ (EO) in their tail region. Such electric signals, also known as Electric Organ Discharges (EODs), are used for objects/prey localization, for the identification of conspecifics, and in social and reproductive behaviour. This feature might have promoted the adaptive radiation of this family by acting as an effective pre-zygotic isolation mechanism. Despite the physiological and evolutionary importance of this trait, the investigation of the genetic basis of its function and modification has so far remained limited. In this study, we aim at: i) identifying constitutive differences in terms of gene expression between electric organ and skeletal muscle (SM) in two mormyrid species of the genus Campylomormyrus: C. compressirostris and C. tshokwe, and ii) exploring cross-specific patterns of gene expression within the two tissues among C. compressirostris, C. tshokwe, and the outgroup species Gnathonemus petersii. RESULTS Twelve paired-end (100 bp) strand-specific RNA-seq Illumina libraries were sequenced, producing circa 330 M quality-filtered short read pairs. The obtained reads were assembled de novo into four reference transcriptomes. In silico cross-tissue DE-analysis allowed us to identify 271 shared differentially expressed genes between EO and SM in C. compressirostris and C.tshokwe. Many of these genes correspond to myogenic factors, ion channels and pumps, and genes involved in several metabolic pathways. Cross-species analysis has revealed that the electric organ transcriptome is more variable in terms of gene expression levels across species than the skeletal muscle transcriptome. CONCLUSIONS The data obtained indicate that: i) the loss of contractile activity and the decoupling of the excitation-contraction processes are reflected by the down-regulation of the corresponding genes in the electric organ's transcriptome; ii) the metabolic activity of the EO might be specialized towards the production and turn-over of membrane structures; iii) several ion channels are highly expressed in the EO in order to increase excitability; iv) several myogenic factors might be down-regulated by transcription repressors in the EO.
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