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Cīrulis A, Nordén AK, Churcher AM, Ramm SA, Zadesenets KS, Abbott JK. Sex-limited experimental evolution drives transcriptomic divergence in a hermaphrodite. Genome Biol Evol 2024; 16:evad235. [PMID: 38155579 PMCID: PMC10786194 DOI: 10.1093/gbe/evad235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 12/12/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023] Open
Abstract
The evolution of gonochorism from hermaphroditism is linked with the formation of sex chromosomes, as well as the evolution of sex-biased and sex-specific gene expression to allow both sexes to reach their fitness optimum. There is evidence that sexual selection drives the evolution of male-biased gene expression in particular. However, previous research in this area in animals comes from either theoretical models or comparative studies of already old sex chromosomes. We therefore investigated changes in gene expression under 3 different selection regimes for the simultaneous hermaphrodite Macrostomum lignano subjected to sex-limited experimental evolution (i.e. selection for fitness via eggs, sperm, or a control regime allowing both). After 21 and 22 generations of selection for male-specific or female-specific fitness, we characterized changes in whole-organism gene expression. We found that female-selected lines had changed the most in their gene expression. Although annotation for this species is limited, gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggest that metabolic changes (e.g. biosynthesis of amino acids and carbon metabolism) are an important adaptive component. As predicted, we found that the expression of genes previously identified as testis-biased candidates tended to be downregulated in the female-selected lines. We did not find any significant expression differences for previously identified candidates of other sex-specific organs, but this may simply reflect that few transcripts have been characterized in this way. In conclusion, our experiment suggests that changes in testis-biased gene expression are important in the early evolution of sex chromosomes and gonochorism.
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Affiliation(s)
- Aivars Cīrulis
- Department of Biology, Lund University, 223 62 Lund, Sweden
- Laboratory of Microbiology and Pathology, Institute of Food Safety, Animal Health and Environment “BIOR,”Riga LV-1076, Latvia
- Faculty of Biology, University of Latvia, Riga LV-1004, Latvia
| | - Anna K Nordén
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Allison M Churcher
- Department of Molecular Biology, National Bioinformatics Infrastructure Sweden, Umeå University, 901 87 Umeå, Sweden
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, 33615 Bielefeld, Germany
- UMR 6553 ECOBIO, Université de Rennes, 35042 Rennes, France
| | - Kira S Zadesenets
- Department of Molecular Genetics, Cell Biology and Bionformatics, The Federal Research Center Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russian Federation
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2
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Wiberg RAW, Brand JN, Viktorin G, Mitchell JO, Beisel C, Schärer L. Genome assemblies of the simultaneously hermaphroditic flatworms Macrostomum cliftonense and Macrostomum hystrix. G3 (BETHESDA, MD.) 2023; 13:jkad149. [PMID: 37398989 PMCID: PMC10468722 DOI: 10.1093/g3journal/jkad149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/05/2023] [Accepted: 06/21/2023] [Indexed: 07/04/2023]
Abstract
The free-living, simultaneously hermaphroditic flatworms of the genus Macrostomum are increasingly used as model systems in various contexts. In particular, Macrostomum lignano, the only species of this group with a published genome assembly, has emerged as a model for the study of regeneration, reproduction, and stem-cell function. However, challenges have emerged due to M. lignano being a hidden polyploid, having recently undergone whole-genome duplication and chromosome fusion events. This complex genome architecture presents a significant roadblock to the application of many modern genetic tools. Hence, additional genomic resources for this genus are needed. Here, we present such resources for Macrostomum cliftonense and Macrostomum hystrix, which represent the contrasting mating behaviors of reciprocal copulation and hypodermic insemination found in the genus. We use a combination of PacBio long-read sequencing and Illumina shot-gun sequencing, along with several RNA-Seq data sets, to assemble and annotate highly contiguous genomes for both species. The assemblies span ∼227 and ∼220 Mb and are represented by 399 and 42 contigs for M. cliftonense and M. hystrix, respectively. Furthermore, high BUSCO completeness (∼84-85%), low BUSCO duplication rates (8.3-6.2%), and low k-mer multiplicity indicate that these assemblies do not suffer from the same assembly ambiguities of the M. lignano genome assembly, which can be attributed to the complex karyology of this species. We also show that these resources, in combination with the prior resources from M. lignano, offer an excellent foundation for comparative genomic research in this group of organisms.
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Affiliation(s)
- R Axel W Wiberg
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel 4051, Switzerland
| | - Jeremias N Brand
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel 4051, Switzerland
| | - Gudrun Viktorin
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel 4051, Switzerland
| | - Jack O Mitchell
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel 4051, Switzerland
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zürich, Basel 4058, Switzerland
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel 4051, Switzerland
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3
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Wiberg RAW, Viktorin G, Schärer L. Mating strategy predicts gene presence/absence patterns in a genus of simultaneously hermaphroditic flatworms. Evolution 2022; 76:3054-3066. [PMID: 36199200 PMCID: PMC10092323 DOI: 10.1111/evo.14635] [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: 05/16/2022] [Accepted: 09/28/2022] [Indexed: 01/22/2023]
Abstract
Gene repertoire turnover is a characteristic of genome evolution. However, we lack well-replicated analyses of presence/absence patterns associated with different selection contexts. Here, we study ∼100 transcriptome assemblies across Macrostomum, a genus of simultaneously hermaphroditic flatworms exhibiting multiple convergent shifts in mating strategy and associated reproductive morphologies. Many species mate reciprocally, with partners donating and receiving sperm at the same time. Other species convergently evolved to mate by hypodermic injection of sperm into the partner. We find that for orthologous transcripts annotated as expressed in the body region containing the testes, sequences from hypodermically inseminating species diverge more rapidly from the model species, Macrostomum lignano, and have a lower probability of being observed in other species. For other annotation categories, simpler models with a constant rate of similarity decay with increasing genetic distance from M. lignano match the observed patterns well. Thus, faster rates of sequence evolution for hypodermically inseminating species in testis-region genes result in higher rates of homology detection failure, yielding a signal of rapid evolution in sequence presence/absence patterns. Our results highlight the utility of considering appropriate null models for unobserved genes, as well as associating patterns of gene presence/absence with replicated evolutionary events in a phylogenetic context.
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Affiliation(s)
- R Axel W Wiberg
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, CH-4051, Switzerland.,Evolutionary Biology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, SE-75236, Sweden
| | - Gudrun Viktorin
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, CH-4051, Switzerland
| | - Lukas Schärer
- Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, CH-4051, Switzerland
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4
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Sticking Together an Updated Model for Temporary Adhesion. Mar Drugs 2022; 20:md20060359. [PMID: 35736161 PMCID: PMC9229212 DOI: 10.3390/md20060359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/20/2022] [Accepted: 05/23/2022] [Indexed: 12/10/2022] Open
Abstract
Non-parasitic flatworms are known to temporarily attach to the substrate by secreting a multicomponent bioadhesive to counteract water movements. However, to date, only species of two higher-level flatworm taxa (Macrostomorpha and Proseriata) have been investigated for their adhesive proteins. Remarkably, the surface-binding protein is not conserved between flatworm taxa. In this study, we sequenced and assembled a draft genome, as well as a transcriptome, and generated a tail-specific positional RNA sequencing dataset of the polyclad Theama mediterranea. This led to the identification of 15 candidate genes potentially involved in temporary adhesion. Using in situ hybridisation and RNA interference, we determined their expression and function. Of these 15 genes, 4 are homologues of adhesion-related genes found in other flatworms. With this work, we provide two novel key components on the flatworm temporary adhesion system. First, we identified a Kringle-domain-containing protein (Tmed-krg1), which was expressed exclusively in the anchor cell. This in silico predicted membrane-bound Tmed-krg1 could potentially bind to the cohesive protein, and a knockdown led to a non-adhesive phenotype. Secondly, a secreted tyrosinase (Tmed-tyr1) was identified, which might crosslink the adhesive proteins. Overall, our findings will contribute to the future development of reversible synthetic glues with desirable properties for medical and industrial applications.
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5
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Wiberg RAW, Brand JN, Schärer L. Faster Rates of Molecular Sequence Evolution in Reproduction-Related Genes and in Species with Hypodermic Sperm Morphologies. Mol Biol Evol 2021; 38:5685-5703. [PMID: 34534329 PMCID: PMC8662610 DOI: 10.1093/molbev/msab276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sexual selection drives the evolution of many striking behaviors and morphologies and should leave signatures of selection at loci underlying these phenotypes. However, although loci thought to be under sexual selection often evolve rapidly, few studies have contrasted rates of molecular sequence evolution at such loci across lineages with different sexual selection contexts. Furthermore, work has focused on separate sexed animals, neglecting alternative sexual systems. We investigate rates of molecular sequence evolution in hermaphroditic flatworms of the genus Macrostomum. Specifically, we compare species that exhibit contrasting sperm morphologies, strongly associated with multiple convergent shifts in the mating strategy, reflecting different sexual selection contexts. Species donating and receiving sperm in every mating have sperm with bristles, likely to prevent sperm removal. Meanwhile, species that hypodermically inject sperm lack bristles, potentially as an adaptation to the environment experienced by hypodermic sperm. Combining functional annotations from the model, Macrostomum lignano, with transcriptomes from 93 congeners, we find genus-wide faster sequence evolution in reproduction-related versus ubiquitously expressed genes, consistent with stronger sexual selection on the former. Additionally, species with hypodermic sperm morphologies had elevated molecular sequence evolution, regardless of a gene's functional annotation. These genome-wide patterns suggest reduced selection efficiency following shifts to hypodermic mating, possibly due to higher selfing rates in these species. Moreover, we find little evidence for convergent amino acid changes across species. Our work not only shows that reproduction-related genes evolve rapidly also in hermaphroditic animals, but also that well-replicated contrasts of different sexual selection contexts can reveal underappreciated genome-wide effects.
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Affiliation(s)
- R Axel W Wiberg
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Jeremias N Brand
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Basel, Switzerland
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6
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Davey PA, Power AM, Santos R, Bertemes P, Ladurner P, Palmowski P, Clarke J, Flammang P, Lengerer B, Hennebert E, Rothbächer U, Pjeta R, Wunderer J, Zurovec M, Aldred N. Omics-based molecular analyses of adhesion by aquatic invertebrates. Biol Rev Camb Philos Soc 2021; 96:1051-1075. [PMID: 33594824 DOI: 10.1111/brv.12691] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022]
Abstract
Many aquatic invertebrates are associated with surfaces, using adhesives to attach to the substratum for locomotion, prey capture, reproduction, building or defence. Their intriguing and sophisticated biological glues have been the focus of study for decades. In all but a couple of specific taxa, however, the precise mechanisms by which the bioadhesives stick to surfaces underwater and (in many cases) harden have proved to be elusive. Since the bulk components are known to be based on proteins in most organisms, the opportunities provided by advancing 'omics technologies have revolutionised bioadhesion research. Time-consuming isolation and analysis of single molecules has been either replaced or augmented by the generation of massive data sets that describe the organism's translated genes and proteins. While these new approaches have provided resources and opportunities that have enabled physiological insights and taxonomic comparisons that were not previously possible, they do not provide the complete picture and continued multi-disciplinarity is essential. This review covers the various ways in which 'omics have contributed to our understanding of adhesion by aquatic invertebrates, with new data to illustrate key points. The associated challenges are highlighted and priorities are suggested for future research.
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Affiliation(s)
- Peter A Davey
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Anne Marie Power
- Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Room 226, Galway, H91 TK33, Ireland
| | - Romana Santos
- Departamento de Biologia Animal, Faculdade de Ciências, Centro de Ciências do Mar e do Ambiente (MARE), Universidade de Lisboa, Lisbon, 1749-016, Portugal
| | - Philip Bertemes
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Pawel Palmowski
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Jessica Clarke
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, U.K
| | - Patrick Flammang
- Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons, Place du Parc 23, Mons, 7000, Belgium
| | - Birgit Lengerer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Elise Hennebert
- Laboratory of Cell Biology, Research Institute for Biosciences, University of Mons, Place du Parc 23, Mons, 7000, Belgium
| | - Ute Rothbächer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Julia Wunderer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstrasse 25, Innsbruck, 6020, Austria
| | - Michal Zurovec
- Biology Centre of the Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice, 370 05, Czech Republic
| | - Nick Aldred
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, U.K
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7
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Brand JN, Wiberg RAW, Pjeta R, Bertemes P, Beisel C, Ladurner P, Schärer L. RNA-Seq of three free-living flatworm species suggests rapid evolution of reproduction-related genes. BMC Genomics 2020; 21:462. [PMID: 32631219 PMCID: PMC7336406 DOI: 10.1186/s12864-020-06862-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/22/2020] [Indexed: 01/03/2023] Open
Abstract
Background The genus Macrostomum consists of small free-living flatworms and contains Macrostomum lignano, which has been used in investigations of ageing, stem cell biology, bioadhesion, karyology, and sexual selection in hermaphrodites. Two types of mating behaviour occur within this genus. Some species, including M. lignano, mate via reciprocal copulation, where, in a single mating, both partners insert their male copulatory organ into the female storage organ and simultaneously donate and receive sperm. Other species mate via hypodermic insemination, where worms use a needle-like copulatory organ to inject sperm into the tissue of the partner. These contrasting mating behaviours are associated with striking differences in sperm and copulatory organ morphology. Here we expand the genomic resources within the genus to representatives of both behaviour types and investigate whether genes vary in their rate of evolution depending on their putative function. Results We present de novo assembled transcriptomes of three Macrostomum species, namely M. hystrix, a close relative of M. lignano that mates via hypodermic insemination, M. spirale, a more distantly related species that mates via reciprocal copulation, and finally M. pusillum, which represents a clade that is only distantly related to the other three species and also mates via hypodermic insemination. We infer 23,764 sets of homologous genes and annotate them using experimental evidence from M. lignano. Across the genus, we identify 521 gene families with conserved patterns of differential expression between juvenile vs. adult worms and 185 gene families with a putative expression in the testes that are restricted to the two reciprocally mating species. Further, we show that homologs of putative reproduction-related genes have a higher protein divergence across the four species than genes lacking such annotations and that they are more difficult to identify across the four species, indicating that these genes evolve more rapidly, while genes involved in neoblast function are more conserved. Conclusions This study improves the genus Macrostomum as a model system, by providing resources for the targeted investigation of gene function in a broad range of species. And we, for the first time, show that reproduction-related genes evolve at an accelerated rate in flatworms.
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Affiliation(s)
- Jeremias N Brand
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.
| | - R Axel W Wiberg
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Philip Bertemes
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
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8
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Weber M, Patlar B, Ramm SA. Effects of two seminal fluid transcripts on post-mating behaviour in the simultaneously hermaphroditic flatworm Macrostomum lignano. J Evol Biol 2020; 33:714-726. [PMID: 32064699 DOI: 10.1111/jeb.13606] [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: 11/26/2019] [Revised: 01/29/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022]
Abstract
The seminal fluid proteins (SFPs) transferred to mating partners along with sperm often play crucial roles in mediating post-mating sexual selection. One way in which sperm donors can maximize their own reproductive success is by modifying the partner's (sperm recipient's) post-copulatory behaviour to prevent or delay re-mating, thereby decreasing the likelihood or intensity of sperm competition. Here, we adopted a quantitative genetic approach combining gene expression and behavioural data to identify candidates that could mediate such a response in the simultaneously hermaphroditic flatworm Macrostomum lignano. We identified two putative SFPs-Mlig-pro46 and Mlig-pro63-linked to both mating frequency and 'suck' frequency, a distinctive behaviour, in which, upon ejaculate receipt, the worm places its pharynx over its female genital opening and apparently attempts to remove the received ejaculate. We, therefore, performed a manipulative experiment using RNA interference-induced knockdown to ask how the loss of Mlig-pro46 and Mlig-pro63 expression, singly and in combination, affects mating frequency, partner suck propensity and sperm competitive ability. None of the knockdown treatments impacted strongly on the mating frequency or sperm competitive ability, but knockdown of Mlig-pro63 resulted in a significantly decreased suck propensity of mating partners. This suggests that Mlig-pro63 may normally act as a cue in the ejaculate to trigger recipient suck behaviour and-given that other proteins in the ejaculate have the opposite effect-could be one component of an ongoing arms race between donors and recipients over the control of ejaculate fate. However, the adaptive significance of Mlig-pro46 and Mlig-pro63 from a donor perspective remains enigmatic.
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Affiliation(s)
- Michael Weber
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Bahar Patlar
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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9
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Schärer L, Brand JN, Singh P, Zadesenets KS, Stelzer C, Viktorin G. A phylogenetically informed search for an alternative
Macrostomum
model species, with notes on taxonomy, mating behavior, karyology, and genome size. J ZOOL SYST EVOL RES 2019. [DOI: 10.1111/jzs.12344] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Lukas Schärer
- Evolutionary Biology Zoological Institute University of Basel Basel Switzerland
| | - Jeremias N. Brand
- Evolutionary Biology Zoological Institute University of Basel Basel Switzerland
| | - Pragya Singh
- Evolutionary Biology Zoological Institute University of Basel Basel Switzerland
| | - Kira S. Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS Novosibirsk Russia
| | | | - Gudrun Viktorin
- Evolutionary Biology Zoological Institute University of Basel Basel Switzerland
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10
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Weber M, Giannakara A, Ramm SA. Seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm Macrostomum lignano. Ecol Evol 2019; 9:13889-13901. [PMID: 31938489 PMCID: PMC6953679 DOI: 10.1002/ece3.5825] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 11/08/2022] Open
Abstract
As a class, seminal fluid proteins are expected to exert strong effects on mating partners due to the selection pressures of sperm competition and sexual conflict. But because of the complexity of this secretion, linking specific proteins to downstream effects on own fitness-via manipulating the reproductive behavior, physiology, and ultimately the sperm utilization of mating partners-is not straightforward. Here, we adopted a systematic gene knockdown approach to screen for seminal fluid-mediated fitness effects in the simultaneously hermaphroditic flatworm Macrostomum lignano. We focused on 18 transcripts in M. lignano seminal fluid, testing how their RNA interference-induced knockdown impacted on three aspects of donor (male) reproductive success: (a) fertility (offspring production of the partner); (b) defensive sperm competitive ability, P 1; and (c) offensive sperm competitive ability, P 2. In general, the knockdown of most individual transcripts appeared to have only a minor impact on male reproductive success, though we found evidence that the knockdown of up to five different transcripts impacted on fertility; the knockdown of two other transcripts resulted in reduced P 2; and knockdown of a further transcript actually increased P 2. We thus identify a number of candidate seminal fluid transcripts that appear to modulate offspring production and sperm competitiveness in M. lignano. That only a minority of transcripts exhibit such a pattern likely reflects both the difficulty of accurately estimating sperm competitiveness and the functional redundancy of seminal fluid.
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Affiliation(s)
- Michael Weber
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
| | - Athina Giannakara
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
| | - Steven A. Ramm
- Department of Evolutionary BiologyBielefeld UniversityBielefeldGermany
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11
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Azlan A, Halim MA, Azzam G. Genome-wide identification and characterization of long intergenic noncoding RNAs in the regenerative flatworm Macrostomum lignano. Genomics 2019; 112:1273-1281. [PMID: 31381967 DOI: 10.1016/j.ygeno.2019.07.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 07/16/2019] [Accepted: 07/30/2019] [Indexed: 01/03/2023]
Abstract
The free-living flatworm Macrostoma lignano (M. lignano) is an emerging model organism for aging and regeneration research. Long intergenic non-coding RNAs (lincRNAs) have important roles in many biological processes such as aging, stem cell maintenance and differentiation. However, to date, there is no systematic identification of lincRNAs in M. lignano. By using public RNA-seq data, we identified a total of 2547 lincRNA transcripts in M. lignano genome. We discovered that M. lignano lincRNAs shared many characteristics with other species such as shorter in length, lower GC content, and lower in expression compared to protein-coding genes. Unlike protein-coding genes, M. lignano lincRNAs showed higher tendency to be expressed in temporal and region-specific fashion. Additionally, co-expression network analysis and functional enrichment suggest that M. lignano lincRNAs have potential roles in regeneration. This study will provide important resources and pave the way for investigations on non-coding genes involved in aging and regeneration.
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Affiliation(s)
- Azali Azlan
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia; USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800 Penang, Malaysia.
| | - Mardani Abdul Halim
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia; USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Ghows Azzam
- School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia; USM-RIKEN International Centre for Ageing Science (URICAS), Universiti Sains Malaysia, 11800 Penang, Malaysia.
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12
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Ramm SA, Lengerer B, Arbore R, Pjeta R, Wunderer J, Giannakara A, Berezikov E, Ladurner P, Schärer L. Sex allocation plasticity on a transcriptome scale: Socially sensitive gene expression in a simultaneous hermaphrodite. Mol Ecol 2019; 28:2321-2341. [PMID: 30891857 DOI: 10.1111/mec.15077] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/04/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022]
Abstract
Phenotypic plasticity can enable organisms to produce optimal phenotypes in multiple environments. A crucial life history trait that is often highly plastic is sex allocation, which in simultaneous hermaphrodites describes the relative investment into the male versus female sex functions. Theory predicts-and morphological evidence supports-that greater investment into the male function is favoured with increasing group size, due to the increasing importance of sperm competition for male reproductive success. Here, we performed a genome-wide gene expression assay to test for such sex allocation plasticity in a model simultaneous hermaphrodite, the free-living flatworm Macrostomum lignano. Based on RNA-Seq data from 16 biological replicates spanning four different group size treatments, we demonstrate that at least 10% of the >75,000 investigated transcripts in M. lignano are differentially expressed according to the social environment, rising to >30% of putative gonad-specific transcripts (spermatogenesis and oogenesis candidates) and tail-specific transcripts (seminal fluid candidates). This transcriptional response closely corresponds to the expected shift away from female and towards male reproductive investment with increasing sperm competition level. Using whole-mount in situ hybridization, we then confirm that many plastic transcripts exhibit the expected organ-specific expression, and RNA interference of selected testis- and ovary-specific candidates establishes that these indeed function in gametogenesis pathways. We conclude that a large proportion of sex-specific transcripts in M. lignano are differentially expressed according to the prevailing ecological conditions and that these are functionally relevant to key reproductive phenotypes. Our study thus begins to bridge organismal and molecular perspectives on sex allocation plasticity.
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Affiliation(s)
- Steven A Ramm
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany.,Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
| | - Birgit Lengerer
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Roberto Arbore
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
| | - Robert Pjeta
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Julia Wunderer
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | | | - Eugene Berezikov
- ERIBA, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter Ladurner
- Institute of Zoology & CMBI, University of Innsbruck, Innsbruck, Austria
| | - Lukas Schärer
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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13
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Patlar B, Weber M, Ramm SA. Genetic and environmental variation in transcriptional expression of seminal fluid proteins. Heredity (Edinb) 2019; 122:595-611. [PMID: 30356222 PMCID: PMC6461930 DOI: 10.1038/s41437-018-0160-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 08/29/2018] [Accepted: 09/18/2018] [Indexed: 12/31/2022] Open
Abstract
Seminal fluid proteins (SFPs) are crucial mediators of sexual selection and sexual conflict. Recent studies have chiefly focused on environmentally induced plasticity as one source of variation in SFP expression, particularly in response to differing sperm competition levels. However, understanding the evolution of a trait in heterogenous environments requires estimates of both environmental and genetic sources of variation, as well as their interaction. Therefore, we investigated how environment (specifically mating group size, a good predictor of sperm competition intensity), genotype and genotype-by-environment interactions affect seminal fluid expression. To do so, we reared 12 inbred lines of a simultaneously hermaphroditic flatworm Macrostomum lignano in groups of either two or eight worms and measured the expression levels of 58 putative SFP transcripts. We then examined the source of variation in the expression of each transcript individually and for multivariate axes extracted from a principal component analysis. We found that mating group size did not affect expression levels according to the single transcript analyses, nor did it affect the first principal component (presumably representing overall investment in seminal fluid production). However, mating group size did affect the relative expression of different transcripts captured by the second principal component (presumably reflecting variation in seminal fluid composition). Most transcripts were genetically variable in their expression level and several exhibited genotype-by-environment interactions; relative composition also showed high genetic variation. Collectively, our results reveal the tightly integrated nature of the seminal fluid transcriptome and provide new insights into the quantitative genetic basis of seminal fluid investment and composition.
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Affiliation(s)
- Bahar Patlar
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany.
| | - Michael Weber
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - Steven A Ramm
- Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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14
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Wunderer J, Lengerer B, Pjeta R, Bertemes P, Kremser L, Lindner H, Ederth T, Hess MW, Stock D, Salvenmoser W, Ladurner P. A mechanism for temporary bioadhesion. Proc Natl Acad Sci U S A 2019; 116:4297-4306. [PMID: 30782790 PMCID: PMC6410801 DOI: 10.1073/pnas.1814230116] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The flatworm Macrostomum lignano features a duo-gland adhesive system that allows it to repeatedly attach to and release from substrates in seawater within a minute. However, little is known about the molecules involved in this temporary adhesion. In this study, we show that the attachment of M. lignano relies on the secretion of two large adhesive proteins, M. lignano adhesion protein 1 (Mlig-ap1) and Mlig-ap2. We revealed that both proteins are expressed in the adhesive gland cells and that their distribution within the adhesive footprints was spatially restricted. RNA interference knockdown experiments demonstrated the essential function of these two proteins in flatworm adhesion. Negatively charged modified sugars in the surrounding water inhibited flatworm attachment, while positively charged molecules impeded detachment. In addition, we found that M. lignano could not adhere to strongly hydrated surfaces. We propose an attachment-release model where Mlig-ap2 attaches to the substrate and Mlig-ap1 exhibits a cohesive function. A small negatively charged molecule is secreted that interferes with Mlig-ap1, inducing detachment. These findings are of relevance for fundamental adhesion science and efforts to mitigate biofouling. Further, this model of flatworm temporary adhesion may serve as the starting point for the development of synthetic reversible adhesion systems for medicinal and industrial applications.
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Affiliation(s)
- Julia Wunderer
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Birgit Lengerer
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
- Biology of Marine Organisms and Biomimetics, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium
| | - Robert Pjeta
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Philip Bertemes
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Thomas Ederth
- Division of Molecular Physics, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Michael W Hess
- Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - David Stock
- Institute for Material Technology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Willi Salvenmoser
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Peter Ladurner
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria;
- Center of Molecular Bioscience Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
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15
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Weber M, Wunderer J, Lengerer B, Pjeta R, Rodrigues M, Schärer L, Ladurner P, Ramm SA. A targeted in situ hybridization screen identifies putative seminal fluid proteins in a simultaneously hermaphroditic flatworm. BMC Evol Biol 2018; 18:81. [PMID: 29848299 PMCID: PMC5977470 DOI: 10.1186/s12862-018-1187-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/30/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Along with sperm, in many taxa ejaculates also contain large numbers of seminal fluid proteins (SFPs). SFPs and sperm are transferred to the mating partner, where they are thought to play key roles in mediating post-mating sexual selection. They modulate the partner's behavior and physiology in ways that influence the reproductive success of both partners, thus potentially leading to sexual conflict. Despite the presumed general functional and evolutionary significance of SFPs, their identification and characterization has to date focused on just a few animal groups, predominantly insects and mammals. Moreover, until now seminal fluid profiling has mainly focused on species with separate sexes. Here we report a comprehensive screen for putative SFPs in the simultaneously hermaphroditic flatworm Macrostomum lignano. RESULTS Based on existing transcriptomic data, we selected 150 transcripts known to be (a) predominantly expressed in the tail region of the worms, where the seminal fluid-producing prostate gland cells are located, and (b) differentially expressed in social environments differing in sperm competition level, strongly implying that they represent a phenotypically plastic aspect of male reproductive allocation in this species. For these SFP candidates, we then performed whole-mount in situ hybridization (ISH) experiments to characterize tissue-specific expression. In total, we identified 98 transcripts that exhibited prostate-specific expression, 76 of which we found to be expressed exclusively in the prostate gland cells; additional sites of expression for the remaining 22 included the testis or other gland cells. Bioinformatics analyses of the prostate-limited candidates revealed that at least 64 are predicted to be secretory proteins, making these especially strong candidates to be SFPs that are transferred during copulation. CONCLUSIONS Our study represents a first comprehensive analysis using a combination of transcriptomic and ISH screen data to identify SFPs based on transcript expression in seminal fluid-producing tissues. We thereby extend the range of taxa for which seminal fluid has been characterized to a flatworm species with a sequenced genome and for which several methods such as antibody staining, transgenesis and RNA interference have been established. Our data provide a basis for testing the functional and evolutionary significance of SFPs.
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Affiliation(s)
- Michael Weber
- Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615 Bielefeld, Germany
| | - Julia Wunderer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Birgit Lengerer
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Marcelo Rodrigues
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
- Current address: School of Natural and Environmental Sciences, Ridley Building, Newcastle University, Newcastle upon Tyne, England NE1 7RU UK
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Biosciences Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria
| | - Steven A. Ramm
- Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615 Bielefeld, Germany
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16
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Grudniewska M, Mouton S, Grelling M, Wolters AHG, Kuipers J, Giepmans BNG, Berezikov E. A novel flatworm-specific gene implicated in reproduction in Macrostomum lignano. Sci Rep 2018; 8:3192. [PMID: 29453392 PMCID: PMC5816591 DOI: 10.1038/s41598-018-21107-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/30/2018] [Indexed: 12/20/2022] Open
Abstract
Free-living flatworms, such as the planarian Schmidtea mediterranea, are extensively used as model organisms to study stem cells and regeneration. The majority of flatworm studies so far focused on broadly conserved genes. However, investigating what makes these animals different is equally informative for understanding its biology and might have biomedical value. We re-analyzed the neoblast and germline transcriptional signatures of the flatworm M. lignano using an improved transcriptome assembly and show that germline-enriched genes have a high fraction of flatworm-specific genes. We further identified the Mlig-sperm1 gene as a member of a novel gene family conserved only in free-living flatworms and essential for producing healthy spermatozoa. In addition, we established a whole-animal electron microscopy atlas (nanotomy) to visualize the ultrastructure of the testes in wild type worms, but also as a reference platform for different ultrastructural studies in M. lignano. This work demonstrates that investigation of flatworm-specific genes is crucial for understanding flatworm biology and establishes a basis for such future research in M. lignano.
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Affiliation(s)
- Magda Grudniewska
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Stijn Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Margriet Grelling
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Anouk H G Wolters
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Jeroen Kuipers
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Ben N G Giepmans
- Department of Cell Biology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Eugene Berezikov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands.
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17
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Jékely G, Melzer S, Beets I, Kadow ICG, Koene J, Haddad S, Holden-Dye L. The long and the short of it - a perspective on peptidergic regulation of circuits and behaviour. J Exp Biol 2018; 221:jeb166710. [PMID: 29439060 DOI: 10.1242/jeb.166710] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neuropeptides are the most diverse class of chemical modulators in nervous systems. They contribute to extensive modulation of circuit activity and have profound influences on animal physiology. Studies on invertebrate model organisms, including the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, have enabled the genetic manipulation of peptidergic signalling, contributing to an understanding of how neuropeptides pattern the output of neural circuits to underpin behavioural adaptation. Electrophysiological and pharmacological analyses of well-defined microcircuits, such as the crustacean stomatogastric ganglion, have provided detailed insights into neuropeptide functions at a cellular and circuit level. These approaches can be increasingly applied in the mammalian brain by focusing on circuits with a defined and identifiable sub-population of neurons. Functional analyses of neuropeptide systems have been underpinned by systematic studies to map peptidergic networks. Here, we review the general principles and mechanistic insights that have emerged from these studies. We also highlight some of the challenges that remain for furthering our understanding of the functional relevance of peptidergic modulation.
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Affiliation(s)
- Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Sarah Melzer
- Howard Hughes Medical Institute, Department of Neurobiology, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Isabel Beets
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Ilona C Grunwald Kadow
- Technical University of Munich, TUM School of Life Sciences, ZIEL - Institute for Food and Health, 85354 Freising, Germany
| | - Joris Koene
- Vrije Universiteit - Ecological Science, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Sara Haddad
- Volen Center for Complex Systems, Brandeis University, Mailstop 013, 415 South Street, Waltham, MA 02454, USA
| | - Lindy Holden-Dye
- Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, UK
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18
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Sun Y, Liu R, Zhao G, Zheng M, Li P, Liu L, Wen J. Genome-Wide Linkage Analysis Identifies Loci for Testicle and Ovary Traits in Chickens. Anim Biotechnol 2018; 29:309-315. [DOI: 10.1080/10495398.2017.1397004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Yanfa Sun
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
- College of Life Science, Longyan University, Longyan, Fujian, P. R. China
| | - Ranran Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Guiping Zhao
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Maiqing Zheng
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Peng Li
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Li Liu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Jie Wen
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
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19
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Schärer L. The varied ways of being male and female. Mol Reprod Dev 2017; 84:94-104. [PMID: 28032683 DOI: 10.1002/mrd.22775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 12/23/2016] [Indexed: 12/18/2022]
Abstract
Our understanding of sexual reproduction is mainly informed by research on gonochorists (i.e., species with separate sexes), including insects, birds, and mammals. But the male and female sexes are not two types of individuals; they actually represent two different reproductive strategies, and in many organisms, these two strategies are distributed among individuals in a population in a variety of ways. For example, sequential hermaphrodites (or sex-changers) exhibit one strategy early in life and later switch to the other, while simultaneous hermaphrodites exhibit both strategies at the same time. There are also many intermediate sexual systems that mix gonochorists and hermaphrodites in the same species and within many organismal groups, shifts occur between these sexual systems. A fascinating collection of six articles in this special issue on Hermaphroditism & Sex Determination impressively documents some important challenges to our understanding of sex determination, and the specification of male and female reproductive function when these need to occur within the same individual rather than in two separate individuals. Moreover, hermaphroditism changes how we need to think about reproductive allocation to sexual functions, how such allocation can be specified, as well as how the sexual system affects sexual conflict and the resulting antagonistic coevolution. Our understanding of sexual reproduction will profit greatly from exploring the varied ways of being male and female. Mol. Reprod. Dev. 84: 94-104, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, Switzerland
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20
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Lengerer B, Wunderer J, Pjeta R, Carta G, Kao D, Aboobaker A, Beisel C, Berezikov E, Salvenmoser W, Ladurner P. Organ specific gene expression in the regenerating tail of Macrostomum lignano. Dev Biol 2017; 433:448-460. [PMID: 28757111 DOI: 10.1016/j.ydbio.2017.07.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/21/2017] [Accepted: 07/27/2017] [Indexed: 11/25/2022]
Abstract
Temporal and spatial characterization of gene expression is a prerequisite for the understanding of cell-, tissue-, and organ-differentiation. In a multifaceted approach to investigate gene expression in the tail plate of the free-living marine flatworm Macrostomum lignano, we performed a posterior-region-specific in situ hybridization screen, RNA sequencing (RNA-seq) of regenerating animals, and functional analyses of selected tail-specific genes. The in situ screen revealed transcripts expressed in the antrum, cement glands, adhesive organs, prostate glands, rhabdite glands, and other tissues. Next we used RNA-seq to characterize temporal expression in the regenerating tail plate revealing a time restricted onset of both adhesive organs and copulatory apparatus regeneration. In addition, we identified three novel previously unannotated genes solely expressed in the regenerating stylet. RNA interference showed that these genes are required for the formation of not only the stylet but the whole male copulatory apparatus. RNAi treated animals lacked the stylet, vesicula granulorum, seminal vesicle, false seminal vesicle, and prostate glands, while the other tissues of the tail plate, such as adhesive organs regenerated normally. In summary, our findings provide a large resource of expression data during homeostasis and regeneration of the morphologically complex tail regeneration and pave the way for a better understanding of organogenesis in M. lignano.
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Affiliation(s)
- Birgit Lengerer
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Julia Wunderer
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Robert Pjeta
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Giada Carta
- Division of Physiology, Medical University of Innsbruck, Schöpfstraße 41/EG, A-6020 Innsbruck, Austria.
| | - Damian Kao
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Aziz Aboobaker
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, 4058 Basel, Switzerland.
| | - Eugene Berezikov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, NL-9713 AV Groningen, The Netherlands.
| | - Willi Salvenmoser
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
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21
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Zadesenets KS, Schärer L, Rubtsov NB. New insights into the karyotype evolution of the free-living flatworm Macrostomum lignano (Platyhelminthes, Turbellaria). Sci Rep 2017; 7:6066. [PMID: 28729552 PMCID: PMC5519732 DOI: 10.1038/s41598-017-06498-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/13/2017] [Indexed: 01/02/2023] Open
Abstract
The free-living flatworm Macrostomum lignano is a model organism for evolutionary and developmental biology studies. Recently, an unusual karyotypic diversity was revealed in this species. Specifically, worms are either ‘normal’ 2n = 8, or they are aneuploid with one or two additional large chromosome(s) (i.e. 2n = 9 or 2n = 10, respectively). Aneuploid worms did not show visible behavioral or morphological abnormalities and were successful in reproduction. In this study, we generated microdissected DNA probes from chromosome 1 (further called MLI1), chromosome 2 (MLI2), and a pair of similar-sized smaller chromosomes (MLI3, MLI4). FISH using these probes revealed that MLI1 consists of contiguous regions homologous to MLI2-MLI4, suggesting that MLI1 arose due to the whole genome duplication and subsequent fusion of one full chromosome set into one large metacentric chromosome. Therefore, one presumably full haploid genome was packed into MLI1, leading to hidden tetraploidy in the M. lignano genome. The study of Macrostomum sp. 8 — a sibling species of M. lignano — revealed that it usually has one additional pair of large chromosomes (2n = 10) showing a high homology to MLI1, thus suggesting hidden hexaploidy in its genome. Possible evolutionary scenarios for the emergence of the M. lignano and Macrostomum sp. 8 genomes are discussed.
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Affiliation(s)
- Kira S Zadesenets
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave., 10, Novosibirsk, 630090, Russian Federation.
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Basel, CH-4051, Switzerland
| | - Nikolay B Rubtsov
- The Federal Research Center Institute of Cytology and Genetics SB RAS, Lavrentiev ave., 10, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Pirogova str., 2, Novosibirsk, 630090, Russian Federation
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22
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Rouhana L, Tasaki J, Saberi A, Newmark PA. Genetic dissection of the planarian reproductive system through characterization of Schmidtea mediterranea CPEB homologs. Dev Biol 2017; 426:43-55. [PMID: 28434803 PMCID: PMC5544531 DOI: 10.1016/j.ydbio.2017.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/30/2017] [Accepted: 04/18/2017] [Indexed: 01/30/2023]
Abstract
Cytoplasmic polyadenylation is a mechanism of mRNA regulation prevalent in metazoan germ cells; it is largely dependent on Cytoplasmic Polyadenylation Element Binding proteins (CPEBs). Two CPEB homologs were identified in the planarian Schmidtea mediterranea. Smed-CPEB1 is expressed in ovaries and yolk glands of sexually mature planarians, and required for oocyte and yolk gland development. In contrast, Smed-CPEB2 is expressed in the testes and the central nervous system; its function is required for spermatogenesis as well as non-autonomously for development of ovaries and accessory reproductive organs. Transcriptome analysis of CPEB knockdown animals uncovered a comprehensive collection of molecular markers for reproductive structures in S. mediterranea, including ovaries, testes, yolk glands, and the copulatory apparatus. Analysis by RNA interference revealed contributions for a dozen of these genes during oogenesis, spermatogenesis, or capsule formation. We also present evidence suggesting that Smed-CPEB2 promotes translation of Neuropeptide Y-8, a prohormone required for planarian sexual maturation. These findings provide mechanistic insight into potentially conserved processes of germ cell development, as well as events involved in capsule deposition by flatworms.
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Affiliation(s)
- Labib Rouhana
- Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA; Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
| | - Junichi Tasaki
- Department of Biological Sciences, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
| | - Amir Saberi
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave., Urbana, IL 61801, USA
| | - Phillip A Newmark
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave., Urbana, IL 61801, USA
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23
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Grudniewska M, Mouton S, Simanov D, Beltman F, Grelling M, de Mulder K, Arindrarto W, Weissert PM, van der Elst S, Berezikov E. Transcriptional signatures of somatic neoblasts and germline cells in Macrostomum lignano. eLife 2016; 5. [PMID: 27997336 PMCID: PMC5173321 DOI: 10.7554/elife.20607] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 12/01/2016] [Indexed: 12/11/2022] Open
Abstract
The regeneration-capable flatworm Macrostomum lignano is a powerful model organism to study the biology of stem cells in vivo. As a flatworm amenable to transgenesis, it complements the historically used planarian flatworm models, such as Schmidtea mediterranea. However, information on the transcriptome and markers of stem cells in M. lignano is limited. We generated a de novo transcriptome assembly and performed the first comprehensive characterization of gene expression in the proliferating cells of M. lignano, represented by somatic stem cells, called neoblasts, and germline cells. Knockdown of a selected set of neoblast genes, including Mlig-ddx39, Mlig-rrm1, Mlig-rpa3, Mlig-cdk1, and Mlig-h2a, confirmed their crucial role for the functionality of somatic neoblasts during homeostasis and regeneration. The generated M. lignano transcriptome assembly and gene expression signatures of somatic neoblasts and germline cells will be a valuable resource for future molecular studies in M. lignano. DOI:http://dx.doi.org/10.7554/eLife.20607.001
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Affiliation(s)
- Magda Grudniewska
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Stijn Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Daniil Simanov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Frank Beltman
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Margriet Grelling
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Katrien de Mulder
- Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Wibowo Arindrarto
- Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Philipp M Weissert
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Stefan van der Elst
- Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Eugene Berezikov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Hubrecht Institute-KNAW, Utrecht, The Netherlands.,University Medical Centre Utrecht, Utrecht, The Netherlands
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24
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Rodrigues M, Ostermann T, Kremeser L, Lindner H, Beisel C, Berezikov E, Hobmayer B, Ladurner P. Profiling of adhesive-related genes in the freshwater cnidarian Hydra magnipapillata by transcriptomics and proteomics. BIOFOULING 2016; 32:1115-1129. [PMID: 27661452 PMCID: PMC5080974 DOI: 10.1080/08927014.2016.1233325] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
The differentiated ectodermal basal disc cells of the freshwater cnidarian Hydra secrete proteinaceous glue to temporarily attach themselves to underwater surfaces. Using transcriptome sequencing and a basal disc-specific RNA-seq combined with in situ hybridisation a highly specific set of candidate adhesive genes was identified. A de novo transcriptome assembly of 55,849 transcripts (>200 bp) was generated using paired-end and single reads from Illumina libraries constructed from different polyp conditions. Differential transcriptomics and spatial gene expression analysis by in situ hybridisation allowed the identification of 40 transcripts exclusively expressed in the ectodermal basal disc cells. Comparisons after mass spectrometry analysis of the adhesive secretion showed a total of 21 transcripts to be basal disc specific and eventually secreted through basal disc cells. This is the first study to survey adhesion-related genes in Hydra. The candidate list presented in this study provides a platform for unravelling the molecular mechanism of underwater adhesion of Hydra.
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Affiliation(s)
- Marcelo Rodrigues
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Thomas Ostermann
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Leopold Kremeser
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | | | - Eugene Berezikov
- ERIBA, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Bert Hobmayer
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Peter Ladurner
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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25
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Rivera-Ingraham GA, Nommick A, Blondeau-Bidet E, Ladurner P, Lignot JH. Salinity stress from the perspective of the energy-redox axis: Lessons from a marine intertidal flatworm. Redox Biol 2016; 10:53-64. [PMID: 27689738 PMCID: PMC5043416 DOI: 10.1016/j.redox.2016.09.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 11/06/2022] Open
Abstract
In the context of global change, there is an urgent need for researchers in conservation physiology to understand the physiological mechanisms leading to the acquisition of stress acclimation phenotypes. Intertidal organisms continuously cope with drastic changes in their environmental conditions, making them outstanding models for the study of physiological acclimation. As the implementation of such processes usually comes at a high bioenergetic cost, a mitochondrial/oxidative stress approach emerges as the most relevant approach when seeking to analyze whole-animal responses. Here we use the intertidal flatworm Macrostomum lignano to analyze the bioenergetics of salinity acclimation and its consequences in terms of reactive oxygen/nitrogen species formation and physiological response to counteract redox imbalance. Measures of water fluxes and body volume suggest that M. lignano is a hyper-/iso-regulator. Higher salinities were revealed to be the most energetically expensive conditions, with an increase in mitochondrial density accompanied by increased respiration rates. Such modifications came at the price of enhanced superoxide anion production, likely associated with a high caspase 3 upregulation. These animals nevertheless managed to live at high levels of environmental salinity through the upregulation of several mitochondrial antioxidant enzymes such as superoxide dismutase. Contrarily, animals at low salinities decreased their respiration rates, reduced their activity and increased nitric oxide formation, suggesting a certain degree of metabolic arrest. A contradictory increase in dichlorofluorescein fluorescence and an upregulation of gluthathione-S-transferase pi 1 (GSTP1) expression were observed in these individuals. If animals at low salinity are indeed facing metabolic depression, the return to seawater may result in an oxidative burst. We hypothesize that this increase in GSTP1 could be a “preparation for oxidative stress”, i.e. a mechanism to counteract the production of free radicals upon returning to seawater. The results of the present study shed new light on how tolerant organisms carry out subcellular adaptations to withstand environmental change. High salinity induces O2·- formation while hypo-salinity increases DCF fluorescence. Hypersalinity is accompanied by upregulation of antioxidant enzymes such as SOD. Hyposalinity causes animals to go into a certain degree of metabolic arrest. Low salinity also causes GST-pi upregulation as a preparation for reoxygenation.
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Affiliation(s)
- Georgina A Rivera-Ingraham
- Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), UMR 9190 MARBEC, University of Montpellier, 34095 Montpellier, France.
| | - Aude Nommick
- Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), UMR 9190 MARBEC, University of Montpellier, 34095 Montpellier, France
| | - Eva Blondeau-Bidet
- Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), UMR 9190 MARBEC, University of Montpellier, 34095 Montpellier, France
| | - Peter Ladurner
- Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Jehan-Hervé Lignot
- Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), UMR 9190 MARBEC, University of Montpellier, 34095 Montpellier, France
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26
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Ramm SA. Exploring the sexual diversity of flatworms: Ecology, evolution, and the molecular biology of reproduction. Mol Reprod Dev 2016; 84:120-131. [PMID: 27292123 DOI: 10.1002/mrd.22669] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Flatworms exhibit huge diversity in their reproductive biology, making this group an excellent model system for exploring how differences among species in reproductive ecology are reflected in the physiological and molecular details of how reproduction is achieved. In this review, I consider five key "lifestyle choices" (i.e., alternative evolutionary/developmental outcomes) that collectively encompass much of flatworm sexual diversity, beginning with the decisions: (i) whether to be free-living or parasitic; (ii) whether to reproduce asexually or sexually; and (iii) whether to be gonochoristic (separate-sexed) or hermaphroditic. I then examine two further decisions involving hermaphroditism: (iv) outcrossing versus selfing and (v) the balance of investment into the male versus the female sex function (sex allocation). Collectively, these lifestyle choices set the basic rules for how reproduction occurs, but as I emphasize in the second part of the review, the reproductive biology of flatworms is also greatly impacted by the near-pervasive and powerful pressure of sexual selection, together with the related phenomena of sperm competition and sexual conflict. Exactly how this plays out, however, is strongly affected by the particular combination of reproductive strategies adopted by each species. Mol. Reprod. Dev. 84: 120-131, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
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27
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Janicke T, Sandner P, Ramm SA, Vizoso DB, Schärer L. Experimentally evolved and phenotypically plastic responses to enforced monogamy in a hermaphroditic flatworm. J Evol Biol 2016; 29:1713-27. [PMID: 27237934 DOI: 10.1111/jeb.12910] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/07/2016] [Accepted: 05/19/2016] [Indexed: 01/13/2023]
Abstract
Sexual selection is considered a potent evolutionary force in all sexually reproducing organisms, but direct tests in terms of experimental evolution of sexual traits are still lacking for simultaneously hermaphroditic animals. Here, we tested how evolution under enforced monogamy affected a suite of reproductive traits (including testis area, sex allocation, genital morphology, sperm morphology and mating behaviour) in the outcrossing hermaphroditic flatworm Macrostomum lignano, using an assay that also allowed the assessment of phenotypically plastic responses to group size. The experiment comprised 32 independent selection lines that evolved under either monogamy or polygamy for 20 generations. While we did not observe an evolutionary shift in sex allocation, we detected effects of the selection regime for two male morphological traits. Specifically, worms evolving under enforced monogamy had a distinct shape of the male copulatory organ and produced sperm with shorter appendages. Many traits that did not evolve under enforced monogamy showed phenotypic plasticity in response to group size. Notably, individuals that grew up in larger groups had a more male-biased sex allocation and produced slightly longer sperm than individuals raised in pairs. We conclude that, in this flatworm, enforced monogamy induced moderate evolutionary but substantial phenotypically plastic responses.
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Affiliation(s)
- T Janicke
- Zoological Institute, University of Basel, Basel, Switzerland. .,Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Ecole Pratique des Hautes Etudes, Université de Montpellier, Université Paul-Valéry Montpellier, Montpellier Cedex 05, France.
| | - P Sandner
- Zoological Institute, University of Basel, Basel, Switzerland
| | - S A Ramm
- Department of Evolutionary Biology, Bielefeld University, Bielefeld, Germany
| | - D B Vizoso
- Zoological Institute, University of Basel, Basel, Switzerland
| | - L Schärer
- Zoological Institute, University of Basel, Basel, Switzerland
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28
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Adhesive organ regeneration in Macrostomum lignano. BMC DEVELOPMENTAL BIOLOGY 2016; 16:20. [PMID: 27255153 PMCID: PMC4890501 DOI: 10.1186/s12861-016-0121-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/23/2016] [Indexed: 11/19/2022]
Abstract
Background Flatworms possess pluripotent stem cells that can give rise to all cell types, which allows them to restore lost body parts after injury or amputation. This makes flatworms excellent model systems for studying regeneration. In this study, we present the adhesive organs of a marine flatworm as a simple model system for organ regeneration. Macrostomum lignano has approximately 130 adhesive organs at the ventral side of its tail plate. One adhesive organ consists of three interacting cells: one adhesive gland cell, one releasing gland cell, and one modified epidermal cell, called an anchor cell. However, no specific markers for these cell types were available to study the regeneration of adhesive organs. Results We tested 15 commercially available lectins for their ability to label adhesive organs and found one lectin (peanut agglutinin) to be specific to adhesive gland cells. We visualized the morphology of regenerating adhesive organs using lectin- and antibody staining as well as transmission electron microscopy. Our findings indicate that the two gland cells differentiate earlier than the connected anchor cells. Using EdU/lectin staining of partially amputated adhesive organs, we showed that their regeneration can proceed in two ways. First, adhesive gland cell bodies are able to survive partial amputation and reconnect with newly formed anchor cells. Second, adhesive gland cell bodies are cleared away, and the entire adhesive organ is build anew. Conclusion Our results provide the first insights into adhesive organ regeneration and describe ten new markers for differentiated cells and tissues in M. lignano. The position of adhesive organ cells within the blastema and their chronological differentiation have been shown for the first time. M. lignano can regenerate adhesive organs de novo but also replace individual anchor cells in an injured organ. Our findings contribute to a better understanding of organogenesis in flatworms and enable further molecular investigations of cell-fate decisions during regeneration. Electronic supplementary material The online version of this article (doi:10.1186/s12861-016-0121-1) contains supplementary material, which is available to authorized users.
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29
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Giannakara A, Schärer L, Ramm SA. Sperm competition-induced plasticity in the speed of spermatogenesis. BMC Evol Biol 2016; 16:60. [PMID: 26956948 PMCID: PMC4784355 DOI: 10.1186/s12862-016-0629-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 03/01/2016] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Sperm competition between rival ejaculates over the fertilization of ova typically selects for the production of large numbers of sperm. An obvious way to increase sperm production is to increase testis size, and most empirical work has focussed on this parameter. Adaptive plasticity in sperm production rate could also arise due to variation in the speed with which each spermatozoon is produced, but whether animals can respond to relevant environmental conditions by modulating the kinetics of spermatogenesis in this way has not been experimentally investigated. RESULTS Here we demonstrate that the simultaneously hermaphroditic flatworm Macrostomum lignano exhibits substantial plasticity in the speed of spermatogenesis, depending on the social context: worms raised under higher levels of sperm competition produce sperm faster. CONCLUSIONS Our findings overturn the prevailing view that the speed of spermatogenesis is a static property of a genotype, and demonstrate the profound impact that social environmental conditions can exert upon a key developmental process. We thus identify, to our knowledge, a novel mechanism through which sperm production rate is maximised under sperm competition.
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Affiliation(s)
- Athina Giannakara
- Evolutionary Biology, Bielefeld University, Morgenbreede 45, 33615, Bielefeld, Germany.
| | - Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.
| | - Steven A Ramm
- Evolutionary Biology, Bielefeld University, Morgenbreede 45, 33615, Bielefeld, Germany.
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30
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Wasik K, Gurtowski J, Zhou X, Ramos OM, Delás MJ, Battistoni G, El Demerdash O, Falciatori I, Vizoso DB, Smith AD, Ladurner P, Schärer L, McCombie WR, Hannon GJ, Schatz M. Genome and transcriptome of the regeneration-competent flatworm, Macrostomum lignano. Proc Natl Acad Sci U S A 2015; 112:12462-7. [PMID: 26392545 PMCID: PMC4603488 DOI: 10.1073/pnas.1516718112] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The free-living flatworm, Macrostomum lignano has an impressive regenerative capacity. Following injury, it can regenerate almost an entirely new organism because of the presence of an abundant somatic stem cell population, the neoblasts. This set of unique properties makes many flatworms attractive organisms for studying the evolution of pathways involved in tissue self-renewal, cell-fate specification, and regeneration. The use of these organisms as models, however, is hampered by the lack of a well-assembled and annotated genome sequences, fundamental to modern genetic and molecular studies. Here we report the genomic sequence of M. lignano and an accompanying characterization of its transcriptome. The genome structure of M. lignano is remarkably complex, with ∼75% of its sequence being comprised of simple repeats and transposon sequences. This has made high-quality assembly from Illumina reads alone impossible (N50=222 bp). We therefore generated 130× coverage by long sequencing reads from the Pacific Biosciences platform to create a substantially improved assembly with an N50 of 64 Kbp. We complemented the reference genome with an assembled and annotated transcriptome, and used both of these datasets in combination to probe gene-expression patterns during regeneration, examining pathways important to stem cell function.
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Affiliation(s)
- Kaja Wasik
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - James Gurtowski
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Xin Zhou
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724; Molecular and Cellular Biology Graduate Program, Stony Brook University, NY 11794
| | - Olivia Mendivil Ramos
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - M Joaquina Delás
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724; Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom
| | - Giorgia Battistoni
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724; Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom
| | - Osama El Demerdash
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Ilaria Falciatori
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724; Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom
| | - Dita B Vizoso
- Department of Evolutionary Biology, Zoological Institute, University of Basel, 4051 Basel, Switzerland
| | - Andrew D Smith
- Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Peter Ladurner
- Department of Evolutionary Biology, Institute of Zoology and Center for Molecular Biosciences Innsbruck, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Lukas Schärer
- Department of Evolutionary Biology, Zoological Institute, University of Basel, 4051 Basel, Switzerland
| | - W Richard McCombie
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Gregory J Hannon
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724; Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom;
| | - Michael Schatz
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724;
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