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Oguchi K, Miura T. Body part-specific development in termite caste differentiation: crosstalk between hormonal actions and developmental toolkit genes. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101183. [PMID: 38428818 DOI: 10.1016/j.cois.2024.101183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/03/2024]
Abstract
In social insects, interactions among colony members trigger caste differentiation with morphological modifications. During caste differentiation in termites, body parts and caste-specific morphologies are modified during postembryonic development under endocrine controls such as juvenile hormone (JH) and ecdysone. In addition to endocrine factors, developmental toolkit genes such as Hox- and appendage-patterning genes also contribute to the caste-specific body part modifications. These toolkits are thought to provide spatial information for specific morphogenesis. During social evolution, the complex crosstalks between physiological and developmental mechanisms should be established, leading to the sophisticated caste systems. This article reviews recent studies on these mechanisms underlying the termite caste differentiation and addresses implications for the evolution of caste systems in termites.
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Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Toru Miura
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan.
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Chen JX, Li WX, Su Q, Lyu J, Zhang YB, Zhang WQ. Comparison of the signaling pathways of wing dimorphism regulated by biotic and abiotic stress in the brown planthopper. INSECT SCIENCE 2023; 30:1046-1062. [PMID: 36382805 DOI: 10.1111/1744-7917.13149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Wing polymorphism is an evolutionary trait that is widely present in various insects and provides a model system for studying the evolutionary significance of insect dispersal. The brown planthopper (BPH, Nilaparvata lugens) can alter its wing morphs under biotic and abiotic stress. However, whether differential signaling pathways are induced by the 2 types of stress remain largely unknown. Here, we screened a number of candidate genes through weighted gene co-expression network analysis (WGCNA) and found that ornithine decarboxylase (NlODC), a key enzyme in the synthesis of polyamines, was associated with wing differentiation in BPH and mainly responded to abiotic stress stimuli. We analyzed the Kyoto Encyclopedia of Genes and Genomes enrichment pathways of differentially expressed genes under the 2 stresses by transcriptomic comparison, and found that biotic stress mainly influenced insulin-related signaling pathways while abiotic stress mainly influenced hormone-related pathways. Moreover, we found that insulin receptor 1 (NlInR1) may regulate wing differentiation of BPH by responding to both biotic and abiotic stress, but NlInR2 only responded to biotic stress. Similarly, the juvenile hormone epoxide hydrolase associated with juvenile hormone degradation and NlODC may regulate wing differentiation mainly through abiotic stress. A model based on the genes and stresses to modulate the wing dimorphism of BPH was proposed. These findings present a comprehensive molecular mechanism for wing polymorphism in BPH induced by biotic and abiotic stress.
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Affiliation(s)
- Jing-Xiang Chen
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wan-Xue Li
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qin Su
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jun Lyu
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yi-Bing Zhang
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Qing Zhang
- State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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Oguchi K, Miura T. Upregulation of Hox genes leading to caste-specific morphogenesis in a termite. EvoDevo 2023; 14:12. [PMID: 37501210 PMCID: PMC10375622 DOI: 10.1186/s13227-023-00216-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/13/2023] [Indexed: 07/29/2023] Open
Abstract
BACKGROUND In social insects, interactions among colony members trigger caste differentiation with morphological modifications. In termite caste differentiation, caste-specific morphologies (such as mandibles in soldiers, genital organs in reproductives or wings in alates) are well developed during post-embryonic development under endocrine controls (e.g., juvenile hormone and ecdysone). Since body part-specific morphogenesis in caste differentiation is hormonally regulated by global factors circulated throughout the body, positional information should be required for the caste-specific and also body part-specific morphogenesis. To identify factors providing the positional information, expression and functional analyses of eight Hox genes were carried out during the three types of caste differentiation (i.e., soldier, neotenic and alate differentiation) in a termite, Hodotermopsis sjostedti. RESULTS Spatio-temporal patterns of Hox gene expression during caste differentiation were elucidated by real-time qPCR, showing the caste-specific upregulations of Hox genes during the differentiation processes. Among eight Hox genes, Deformed (Dfd) was upregulated specifically in mandibles in soldier differentiation, abdominal-A (abd-A) and Abdominal-B (Abd-B) were upregulated in the abdomen in neotenic differentiation, while Sex-comb reduced (Scr) and Antennapedia (Antp) were upregulated during alate differentiation. Furthermore, RNAi knockdown of Dfd in soldier differentiation and of abd-A and Abd-B in neotenic differentiation distorted the modifications of caste-specific morphologies. CONCLUSIONS Gene expression and functional analyses in this study revealed that, in the caste differentiation in termites, upregulation of Hox genes provide positional identities of body segments, resulting in the caste-specific morphogenesis. The acquisition of such developmental modifications would have enabled the evolution of sophisticated caste systems in termites.
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Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan.
| | - Toru Miura
- Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan
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One genome, multiple phenotypes: decoding the evolution and mechanisms of environmentally induced developmental plasticity in insects. Biochem Soc Trans 2023; 51:675-689. [PMID: 36929376 DOI: 10.1042/bst20210995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/16/2023] [Accepted: 02/21/2023] [Indexed: 03/18/2023]
Abstract
Plasticity in developmental processes gives rise to remarkable environmentally induced phenotypes. Some of the most striking and well-studied examples of developmental plasticity are seen in insects. For example, beetle horn size responds to nutritional state, butterfly eyespots are enlarged in response to temperature and humidity, and environmental cues also give rise to the queen and worker castes of eusocial insects. These phenotypes arise from essentially identical genomes in response to an environmental cue during development. Developmental plasticity is taxonomically widespread, affects individual fitness, and may act as a rapid-response mechanism allowing individuals to adapt to changing environments. Despite the importance and prevalence of developmental plasticity, there remains scant mechanistic understanding of how it works or evolves. In this review, we use key examples to discuss what is known about developmental plasticity in insects and identify fundamental gaps in the current knowledge. We highlight the importance of working towards a fully integrated understanding of developmental plasticity in a diverse range of species. Furthermore, we advocate for the use of comparative studies in an evo-devo framework to address how developmental plasticity works and how it evolves.
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Guo N, Ma H, Han H, Yan F, Gao H, Zhang Y, Gao S. Phenotypic and Differential Gene Expression Analyses of Phase Transition in Oedaleus asiaticus under High-Density Population Stress. INSECTS 2022; 13:1034. [PMID: 36354858 PMCID: PMC9697361 DOI: 10.3390/insects13111034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
The high-density-dependent phase change from solitary to gregarious individuals in locusts is a typical example of phenotypic plasticity. However, the underlying molecular mechanism is not clear. In this study, first, Oedaleus asiaticus were treated with high-density population stress and then analyzed by Illumina sequencing on days 1, 3, 5, and 7 of the body color change to identify the stage-specific differentially expressed genes (DEGs). The KEGG pathway enrichment analysis of the identified DEGs revealed their role in metabolic pathways. Furthermore, the expression patterns of the nine key DEGs were studied in detail; this showed that the material change in locusts began on the third day of the high-density treatment, with the number of DEGs being the largest, indicating the importance of this period in the phase transition. In addition, the phenotypic change involved several key genes of important regulatory pathways, possibly working in a complex network. Phenotypic plasticity in locusts is multifactorial, involving multilevel material network interactions. This study improves the mechanistic understanding of phenotypic variation in insects at the genetic level.
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Affiliation(s)
- Na Guo
- Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot 010010, China
| | - Hongyue Ma
- Research Center for Grassland Entomology, Inner Mongolia University for Nationalities, Tongliao 028000, China
| | - Haibin Han
- Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot 010010, China
| | - Feng Yan
- Forest Pest Management and Quarantine Station of Ordos, Ordos 017010, China
| | - Haiyan Gao
- Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot 010010, China
| | - Yuanyuan Zhang
- Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot 010010, China
| | - Shujing Gao
- Institute of Grassland Research, Chinese Academy of Agricultural Science, Hohhot 010010, China
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Bai Y, Pei XJ, Ban N, Chen N, Liu SN, Li S, Liu TX. Nutrition-dependent juvenile hormone sensitivity promotes flight-muscle degeneration during the aphid dispersal-reproduction transition. Development 2022; 149:275958. [DOI: 10.1242/dev.200891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/28/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
In insects, the loss of flight typically involves a dispersal-reproduction transition, but the underlying molecular mechanisms remain poorly understood. In the parthenogenetic pea aphid Acyrthosiphon pisum, winged females undergo flight-muscle degeneration after flight and feeding on new host plants. Similarly, topical application of a juvenile hormone (JH) mimic to starved aphids also induces flight-muscle degeneration. We found that feeding preferentially upregulated the expression of the JH receptor gene Met and a JH-inducible gene, Kr-h1, in the flight muscles, and, thus, enhanced tissue-specific JH sensitivity and signaling. RNAi-mediated knockdown of Kr-h1 prevented flight-muscle degeneration. Likewise, blocking nutritional signals by pharmacological inhibition of the target of rapamycin complex 1 (TORC1) impaired JH sensitivity of the flight muscles in feeding aphids and subsequently delayed muscle degeneration. RNA-sequencing analysis revealed that enhanced JH signaling inhibited the transcription of genes involved in the tricarboxylic acid cycle, likely resulting in reduction of the energy supply, mitochondrial dysfunction and muscle-fiber breakdown. This study shows that nutrient-dependent hormone sensitivity regulates developmental plasticity in a tissue-specific manner, emphasizing a relatively underappreciated mechanism of hormone sensitivity in modulating hormone signaling.
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Affiliation(s)
- Yu Bai
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University 1 , Guangzhou 510631 , China
- State Key Laboratory of Crop Stress Biology for Arid Areas and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University 2 , Yangling 712100 , China
| | - Xiao-Jin Pei
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University 1 , Guangzhou 510631 , China
| | - Ning Ban
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University 3 , Qingdao 266109 , China
| | - Nan Chen
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University 1 , Guangzhou 510631 , China
| | - Su-Ning Liu
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University 1 , Guangzhou 510631 , China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University 1 , Guangzhou 510631 , China
| | - Tong-Xian Liu
- Institute of Entomology, Guizhou University 4 , Guiyang 550025 , China
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Soldier Caste-Specific Protein 1 Is Involved in Soldier Differentiation in Termite Reticulitermes aculabialis. INSECTS 2022; 13:insects13060502. [PMID: 35735839 PMCID: PMC9224846 DOI: 10.3390/insects13060502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023]
Abstract
Termite soldiers are a unique caste among social insects, and their differentiation can be induced by Juvenile hormone (JH) from workers through two molts (worker–presoldier–soldier). However, the molecular mechanism underlying the worker-to-soldier transformation in termites is poorly understood. To explore the mechanism of soldier differentiation induced by JH, the gene soldier caste-specific protein 1 (RaSsp1, NCBI accession no: MT861054.1) in R. aculabialis was cloned, and its function was studied. This gene was highly expressed in the soldier caste, and the protein RsSsp1 was similar to the JHBP (JH-binding protein) domain-containing protein by Predict Protein online. In addition, JHIII could be anchored in the hydrophobic cage of RaSsp1 as the epoxide of the JHBP-bound JH according to the protein ligand molecular docking online tool AutoDock. The functional studies indicated that knocking down of the RaSsp1 shorted the presoldier’s head capsule, reduced mandible size, delayed molting time and decreased molting rate (from worker to presoldier) at the beginning of worker gut-purging. Furthermore, knocking down of the RaSsp1 had a more pronounced effect on soldier differentiation (from presoldier to soldier), and manifested in significantly shorter mandibles, rounder head capsules, and lower molting rate (from worker to presoldier) at the beginning of presoldier gut-purging. Correspondingly, the expressions of JH receptor Methoprene-tolerant (Met), the JH-inducible transcription factor Krüppel homolog1 (Kr-h1) and ecdysone signal genes Broad-complex (Br-C) were downregulated when knocking down the RaSsp1 at the above two stages. All these results that RaSsp1 may be involved in soldier differentiation from workers by binding and transporting JH.
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Understanding of superorganisms: collective behavior, differentiation and social organization. ARTIFICIAL LIFE AND ROBOTICS 2022. [DOI: 10.1007/s10015-022-00754-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Coors A, Falkenhain AM, Scheurer M, Länge R. Evidence for Specific Receptor-Mediated Toxicity of Pharmaceuticals in Aquatic Organisms Derived from Acute and Chronic Standard Endpoints. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:601-613. [PMID: 33595135 DOI: 10.1002/etc.5018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/17/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
The toxicity of 17 active pharmaceutical ingredients (APIs) was investigated using standardized acute and chronic tests with Daphnia magna and 2 algae species. Chronic toxicity was generally greater for Daphnia than for algae. Compilation of additional data resulted in 100 APIs for which the acute-to-chronic ratio (ACR) was determined for Daphnia. The frequency of high ACRs (~20% with ACRs > 100) indicates that specific receptor-mediated toxicity toward D. magna is rather common among APIs. The 11 APIs with ACRs > 1000 included lipid-modifying agents, immunosuppressants, antibiotics, antineoplastics, antiobesics, antivirals, and antihistamines. There was no consistent association between ACR and chronic toxicity, ionization status, or lipophilicity. High ACRs were not exclusively associated with the presence of orthologs of the pharmacological target in Daphnia. Statins, acetylcholinesterase inhibitors, and antihistamines are discussed in more detail regarding the link between targets and toxic mode of action. For acetylcholinesterase inhibitors, receptor-mediated toxicity was already apparent after acute exposure, whereas the high ACR and chronic toxicity of some antihistamines probably related to interaction with a secondary rather than the primary pharmacological target. Acute or modeled chronic toxicity estimates have often been used for prioritizing pharmaceuticals. This may be seriously misleading because chronic effects are currently not predictable for APIs with specific receptor-mediated toxicity. However, it is exactly these APIs that are the most relevant in terms of environmental risks. Environ Toxicol Chem 2022;41:601-613. © 2021 SETAC.
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Affiliation(s)
- Anja Coors
- ECT Oekotoxikologie, Flörsheim/Main, Germany
- Environment Department, University of York, Heslington, York, UK
| | | | - Marco Scheurer
- Deutscher Verein des Gas- und Wasserfaches-Technologiezentrum Wasser, Karlsruhe, Germany
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Abbot P. Defense in Social Insects: Diversity, Division of Labor, and Evolution. ANNUAL REVIEW OF ENTOMOLOGY 2022; 67:407-436. [PMID: 34995089 DOI: 10.1146/annurev-ento-082521-072638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
All social insects defend their colony from predators, parasites, and pathogens. In Oster and Wilson's classic work, they posed one of the key paradoxes about defense in social insects: Given the universal necessity of defense, why then is there so much diversity in mechanisms? Ecological factors undoubtedly are important: Predation and usurpation have imposed strong selection on eusocial insects, and active defense by colonies is a ubiquitous feature of all social insects. The description of diverse insect groups with castes of sterile workers whose main duty is defense has broadened the purview of social evolution in insects, in particular with respect to caste and behavior. Defense is one of the central axes along which we can begin to organize and understand sociality in insects. With the establishment of social insect models such as the honey bee, new discoveries are emerging regarding the endocrine, neural, and gene regulatory mechanisms underlying defense in social insects. The mechanisms underlying morphological and behavioral defense traits may be shared across diverse groups, providing opportunities for identifying both conserved and novel mechanisms at work. Emerging themes highlight the context dependency of and interaction between factors that regulate defense in social insects.
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Affiliation(s)
- Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA;
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Yamaguchi H, Hirose M, Nakamura M, Udagawa S, Oguchi K, Shinji J, Kohtsuka H, Miura T. Developmental Process of a Heterozooid: Avicularium Formation in a Bryozoan, Bugulina californica. Zoolog Sci 2021; 38:203-212. [PMID: 34057344 DOI: 10.2108/zs200143] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/25/2020] [Indexed: 11/17/2022]
Abstract
In bryozoans (phylum Bryozoa), representative colonial animals mostly found in marine environments, some species possess different types of individuals (heterozooids) specialized in different functions such as defense or structural support for their colonies. Among them, the best-known heterozooids are the avicularia, known to function as defenders. The differentiation processes of heterozooids, including avicularia, should be important keys to understand the evolutionary significance of bryozoans. However, the developmental process of avicularium formation remains to be fully understood. In this study, therefore, in order to understand the detailed developmental process and timing of avicularium formation, extensive observations were carried out in a bryozoan species, Bugulina californica (Cheilostomata, Bugulidae), that possesses adventitious avicularia, by performing stereomicroscopy on live materials, in addition to scanning electron microscopy and histological observations. The whole process can be divided into seven stages based on developmental events. Especially notably, at the earlier stages, there are three major budding events that produce proliferating cell masses corresponding to primordial tissues: (1) budding of the peduncle cushion at the outer margin of the distal part of a young autozooid, (2) budding of the head-part primordium from the peduncle cushion, and (3) budding of the polypide inside the head part. Experimental control of temperature showed that 20°C would be the best to maintain B. californica colonies.
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Affiliation(s)
- Haruka Yamaguchi
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Masato Hirose
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Mayuko Nakamura
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Sumio Udagawa
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Kohei Oguchi
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
| | - Junpei Shinji
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Hisanori Kohtsuka
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Toru Miura
- Misaki Marine Biological Station, Misaki, Miura, Kanagawa 238-0225, Japan,
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Adhitama N, Kato Y, Matsuura T, Watanabe H. Roles of and cross-talk between ecdysteroid and sesquiterpenoid pathways in embryogenesis of branchiopod crustacean Daphnia magna. PLoS One 2020; 15:e0239893. [PMID: 33035251 PMCID: PMC7546464 DOI: 10.1371/journal.pone.0239893] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/15/2020] [Indexed: 11/19/2022] Open
Abstract
The ecdysteroid and sesquiterpenoid pathways control growth, developmental transition, and embryogenesis in insects. However, the function of orthologous genes and the cross-talk between both pathways remain largely uncharacterized in non-insect arthropods. Spook (Spo) and Juvenile hormone acid o-methyltransferase (Jhamt) have been suggested to function as rate-limiting factors in ecdysteroid and sesquiterpenoid biosynthesis, respectively, in insects. In this study, we report on the functions of Spo and Jhamt and the cross-talk between them in embryos of the branchiopod crustacean Daphnia magna. Spo expression was activated at the onset of gastrulation, with the depletion of Spo transcript by RNAi resulting in developmental arrest at this stage. This phenotype could be partially rescued by supplementation with 20-hydroxyecdysone, indicating that Spo may play the same role in ecdysteroid biosynthesis in early embryos, as reported in insects. After hatching, Spo expression was repressed, while Jhamt expression was activated transiently, despite its silencing during other embryonic stages. Jhamt RNAi showed little effect on survival, but shortened the embryonic period. Exposure to the sesquiterpenoid analog Fenoxycarb extended the embryonic period and rescued the Jhamt RNAi phenotype, demonstrating a previously unidentified role of sesquiterpenoid in the repression of precocious embryogenesis. Interestingly, the knockdown of Jhamt resulted in the derepression of ecdysteroid biosynthesis genes, including Spo, similar to regulation during insect hormonal biosynthesis. Sesquiterpenoid signaling via the Methoprene-tolerant gene was found to be responsible for the repression of ecdysteroid biosynthesis genes. It upregulated an ortholog of CYP18a1 that degrades ecdysteroid in insects. These results illuminate the conserved and specific functions of the ecdysteroid and sesquiterpenoid pathways in Daphnia embryos. We also infer that the common ancestor of branchiopod crustaceans and insects exhibited antagonism between the two endocrine hormones before their divergence 400 million years ago.
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Affiliation(s)
- Nikko Adhitama
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
- Biotechnology Global Human Resource Development Program, Division of Advanced Science and Biotechnology, Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Yasuhiko Kato
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
- Frontier Research Base of Global Young Researchers, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Tomoaki Matsuura
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Hajime Watanabe
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
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Riddiford LM. Rhodnius, Golden Oil, and Met: A History of Juvenile Hormone Research. Front Cell Dev Biol 2020; 8:679. [PMID: 32850806 PMCID: PMC7426621 DOI: 10.3389/fcell.2020.00679] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/06/2020] [Indexed: 12/13/2022] Open
Abstract
Juvenile hormone (JH) is a unique sesquiterpenoid hormone which regulates both insect metamorphosis and insect reproduction. It also may be utilized by some insects to mediate polyphenisms and other life history events that are environmentally regulated. This article details the history of the research on this versatile hormone that began with studies by V. B. Wigglesworth on the "kissing bug" Rhodnius prolixus in 1934, through the discovery of a natural source of JH in the abdomen of male Hyalophora cecropia moths by C. M. Williams that allowed its isolation ("golden oil") and identification, to the recent research on its receptor, termed Methoprene-tolerant (Met). Our present knowledge of cellular actions of JH in metamorphosis springs primarily from studies on Rhodnius and the tobacco hornworm Manduca sexta, with recent studies on the flour beetle Tribolium castaneum, the silkworm Bombyx mori, and the fruit fly Drosophila melanogaster contributing to the molecular understanding of these actions. Many questions still need to be resolved including the molecular basis of competence to metamorphose, differential tissue responses to JH, and the interaction of nutrition and other environmental signals regulating JH synthesis and degradation.
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Affiliation(s)
- Lynn M Riddiford
- Department of Biology, Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, United States
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Male neotenic reproductives accelerate additional differentiation of female reproductives by lowering JH titer in termites. Sci Rep 2020; 10:9435. [PMID: 32523105 PMCID: PMC7286905 DOI: 10.1038/s41598-020-66403-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/19/2020] [Indexed: 12/02/2022] Open
Abstract
Eusocial insects exhibit reproductive division of labor, in which only a fraction of colony members differentiate into reproductives. In termites, reproductives of both sexes are present in a colony and constantly engaged in reproduction. It has been suggested that the sex ratio of reproductives is maintained by social interactions. The presence of reproductives is known to inhibit the additional differentiation of same-sex reproductives, while it promotes the differentiation of opposite-sex reproductives. In this study, using the damp-wood termite Hodotermopsis sjostedti, physiological effects of male/female reproductives on the differentiation of supplementary reproductives (neotenics) were examined. The results showed that the only male-neotenic condition, i.e., the presence of male neotenics in the absence of female neotenics, accelerated the neotenic differentiation from female workers (i.e., pseudergates). Under this condition, the rise of juvenile hormone (JH) titer was repressed in females, and the application of a JH analog inhibited the female neotenic differentiation, indicating that the low JH titer leads to rapid differentiation. Thus, the only male-neotenic condition that actively promotes reproductive differentiation by manipulating physiological condition of females is suggested to be a mechanism underlying sexual asymmetry in reproductive function, which may lead the female-biased sex allocation of reproductives.
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Miura T, Maekawa K. The making of the defensive caste: Physiology, development, and evolution of the soldier differentiation in termites. Evol Dev 2020; 22:425-437. [PMID: 32291940 DOI: 10.1111/ede.12335] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 02/11/2020] [Accepted: 03/08/2020] [Indexed: 12/29/2022]
Abstract
Termites (Blattodea, Termitoidea, or Isoptera) constitute one of the major lineages of eusocial insects. In termite societies, multiple types of functional individuals, that is, castes, perform divisions of labors to coordinate social behaviors. Among other castes, the soldier caste is distinctive since it is sterile and exclusively specialized into defensive behavior with largely modified morphological features. Therefore, many of the previous studies have been focused on soldiers, in terms of ecology, behavior, and evolution as well as developmental and physiological mechanisms. This article overviews the accumulation of studies especially focusing on the developmental and physiological mechanisms underlying the soldier differentiation in termites. Furthermore, the evolutionary trajectories that have led the acquisition of soldier caste and have diversified the soldier characteristics in association with the social evolution are discussed.
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Affiliation(s)
- Toru Miura
- Department of Biological Sciences, Misaki Marine Biological Station, School of Science, The University of Tokyo, Japan
| | - Kiyoto Maekawa
- Department of Biology, Faculty of Science, Academic Assembly, University of Toyama, Toyama, Japan
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Hasegawa T, Hasebe M, Shiga S. Immunohistochemical and Direct Mass Spectral Analyses of Plautia stali Myoinhibitory Peptides in the Cephalic Ganglia of the Brown-Winged Green Bug Plautia stali. Zoolog Sci 2020; 37:42-49. [PMID: 32068373 DOI: 10.2108/zs190092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/14/2019] [Indexed: 11/17/2022]
Abstract
For seasonal adaptation, the brown-winged green bug Plautia stali (Hemiptera: Pentatomidae) enters reproductive diapause by suppressing juvenile hormone biosynthesis. Plautia stali myoinhibitory peptides (Plast-MIPs) are known to have allatostatic effects and to suppress juvenile hormone biosynthesis. We examined Plast-MIP-producing neurons in the brain with immunohistochemistry and Fourier transform ion cyclotron resonance mass spectrometry. Rabbit polyclonal antiserum against Plast-MIP revealed immunoreactive cells in seven regions of the brain, including the posterior antennal lobe, basal optic lobe, dorsal anterior protocerebrum, ventrolateral protocerebrum, pars intercerebralis, posterior protocerebrum, and dorsal posterior region to the calyx of the mushroom body, aside from the gnathal ganglion. Anatomical locations of the immunoreactive cells in the pars intercerebralis and dorsal posterior region to the mushroom body calyx partly overlapped with the cell body location stained by retrograde dye fills from the corpus allatum and corpus cardiacum complex. Direct mass spectrometry revealed the molecular ion peaks corresponding to the predictive mass of Plast-MIPs in the pars intercerebralis and the corpus allatum-corpus cardiacum complex. Plast-MIP immunoreactivity in different cell types suggests that Plast-MIPs have different functions in the cephalic ganglia. Considering the anatomical location of neurons projecting to the corpus allatum-corpus cardiacum and results of mass spectrometry, Plast-MIP immunoreactive cells in the pars intercerebralis may play a role in suppressing juvenile hormone biosynthesis.
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Affiliation(s)
- Tomohisa Hasegawa
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.,These authors contributed equally to this work
| | - Masaharu Hasebe
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.,These authors contributed equally to this work
| | - Sakiko Shiga
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan,
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17
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Sugime Y, Oguchi K, Gotoh H, Hayashi Y, Matsunami M, Shigenobu S, Koshikawa S, Miura T. Termite soldier mandibles are elongated by dachshund under hormonal and Hox gene controls. Development 2019; 146:dev.171942. [PMID: 30833380 DOI: 10.1242/dev.171942] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/12/2019] [Indexed: 11/20/2022]
Abstract
In social insects, interactions among colony members trigger caste differentiation with morphological modifications. In termite soldier differentiation, the mandible size considerably increases through two moltings (via the presoldier stage) under the control of juvenile hormone (JH). Regulatory genes are predicted to provide patterning information that induces the mandible-specific cell proliferation. To identify factors responsible for the mandibular enlargement, expression analyses of 18 candidate genes were carried out in the termite Hodotermopsis sjostedti Among those, dachshund (dac), which identifies the intermediate domain along the proximodistal appendage axis, showed mandible-specific upregulation prior to the molt into presoldiers, which can explain the pattern of cell proliferation for the mandibular elongation. Knockdown of dac by RNAi reduced the mandibular length and distorted its morphology. Furthermore, the epistatic relationships among Methoprene tolerant, Insulin receptor, Deformed (Dfd) and dac were revealed by combined RNAi and qRT-PCR analyses, suggesting that dac is regulated by Dfd, downstream of the JH and insulin signaling pathways. Thus, caste-specific morphogenesis is controlled by interactions between the factors that provide spatial information and physiological status.
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Affiliation(s)
- Yasuhiro Sugime
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | - Kohei Oguchi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.,Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan
| | - Hiroki Gotoh
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.,Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Yoshinobu Hayashi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.,Department of Biology, Keio University, Yokohama, Kanagawa, 223-8521, Japan
| | - Masatoshi Matsunami
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan.,Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, 903-0215, Japan
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, 444-8585, Japan
| | - Shigeyuki Koshikawa
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | - Toru Miura
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan .,Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan
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18
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Tanaka M. Ecology, Evolution and Development. Dev Growth Differ 2019; 61:3-4. [DOI: 10.1111/dgd.12586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mikiko Tanaka
- School of Life Science and Technology; Tokyo Institute of Technology; Yokohama Japan
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