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Löptien J, Vesting S, Dobler S, Mohammadi S. Evaluating the efficacy of protein quantification methods on membrane proteins. bioRxiv 2024:2024.04.02.587709. [PMID: 38617264 PMCID: PMC11014622 DOI: 10.1101/2024.04.02.587709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Protein quantification is an important tool for a wide range of biological applications. The most common broadscale methods include the Lowry, bicinchoninic acid (BCA), and Coomassie Bradford assays. Despite their wide applicability, the mechanisms of action imply that these methods may not be ideal for large transmembrane proteins due to the proteins' integration in the plasma membrane. Here, we investigate this problem by assessing the efficacy and applicability of these three common protein quantification methods on a candidate transmembrane protein - the Na,K-ATPase (NKA). We compared these methods to an ELISA, which we newly developed and describe here for the quantification of NKA. The use of a relative standard curve allows this ELISA to be easily adapted to other proteins and across the animal kingdom. Our results revealed that the three conventional methods significantly underestimate the concentration of NKA compared to the ELISA. Further, by applying the protein concentrations determined by the different methods to in vitro assays, we found that variation in the resulting data was consistently low when the assay reactions were prepared based on concentrations determined from the ELISA. Thus, when target protein concentrations vary across samples, the conventional quantification methods cannot produce reliable results in downstream applications. In contrast, the ELISA we describe here consistently provides robust results.
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2
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Baum M, Dobler S. Fecal Deployment: An Alternative Way of Defensive Host Plant Cardenolide Use by Lilioceris merdigera Larvae. J Chem Ecol 2024; 50:63-70. [PMID: 38062246 PMCID: PMC10991028 DOI: 10.1007/s10886-023-01465-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 04/04/2024]
Abstract
The brilliant red Lilioceris merdigera (Coleoptera, Chrysomelidae) can spend its entire life cycle on the cardenolide-containing plant Convallaria majalis (lily of the valley) and forms stable populations on this host. Yet, in contrast to many other insects on cardenolide-containing plants L. merdigera does not sequester these plant toxins in the body but rather both adult beetles and larvae eliminate ingested cardenolides with the feces. Tracer feeding experiments showed that this holds true for radioactively labeled ouabain and digoxin, a highly polar and a rather apolar cardenolide. Both compounds or their derivatives are incorporated in the fecal shields of the larvae. The apolar digoxin, but not the polar ouabain, showed a deterrent effect on the generalist predatory ant Myrmica rubra, which occurs in the habitat of L. merdigera. The deterrent effect was detected for digoxin both in choice and feeding time assays. In a predator choice assay, a fecal shield derived from a diet of cardenolide-containing C. majalis offered L. merdigera larvae better protection from M. rubra than one derived from non-cardenolide Allium schoenoprasum (chives) or no fecal shield at all. Thus, we here present data suggesting a new way how insects may gain protection by feeding on cardenolide-containing plants.
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Affiliation(s)
- Michael Baum
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
- Chemistry Education Department, IPN, Leibniz Institute for Science and Mathematics Education, Olshausenstraße 62, 24118, Kiel, Germany.
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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3
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Herbertz M, Dalla S, Wagschal V, Turjalei R, Heiser M, Dobler S. Coevolutionary escalation led to differentially adapted paralogs of an insect's Na,K-ATPase optimizing resistance to host plant toxins. Mol Ecol 2023. [PMID: 37296537 DOI: 10.1111/mec.17041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/24/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Cardiac glycosides are chemical defence toxins known to fatally inhibit the Na,K-ATPase (NKA) throughout the animal kingdom. Several animals, however, have evolved target-site insensitivity through substitutions in the otherwise highly conserved cardiac glycoside binding pocket of the NKA. The large milkweed bug, Oncopeltus fasciatus, shares a long evolutionary history with cardiac glycoside containing plants that led to intricate adaptations. Most strikingly, several duplications of the bugs' NKA1α gene provided the opportunity for differential resistance-conferring substitutions and subsequent sub-functionalization of the enzymes. Here, we analysed cardiac glycoside resistance and ion pumping activity of nine functional NKA α/β-combinations of O. fasciatus expressed in cell culture. We tested the enzymes with two structurally distinct cardiac glycosides, calotropin, a host plant compound, and ouabain, a standard cardiac glycoside. The identity and number of known resistance-conferring substitutions in the cardiac glycoside binding site significantly impacted activity and toxin resistance in the three α-subunits. The β-subunits also influenced the enzymes' characteristics, yet to a lesser extent. Enzymes containing the more ancient αC-subunit were inhibited by both compounds but much more strongly by the host plant toxin calotropin than by ouabain. The sensitivity to calotropin was diminished in enzymes containing the more derived αB and αA, which were only marginally inhibited by both cardiac glycosides. This trend culminated in αAβ1 having higher resistance against calotropin than against ouabain. These results support the coevolutionary escalation of plant defences and herbivore tolerance mechanisms. The possession of multiple paralogs additionally mitigates pleiotropic effects by compromising between ion pumping activity and resistance.
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Affiliation(s)
- Marlena Herbertz
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Safaa Dalla
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Vera Wagschal
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Rohin Turjalei
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Marlies Heiser
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Susanne Dobler
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
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4
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Herbertz M, Lohr J, Lohr C, Dobler S. Knockdown of Na,K-ATPase β-subunits in Oncopeltus fasciatus induces molting problems and alterations in tracheal morphology. Insect Sci 2023; 30:375-397. [PMID: 36102008 DOI: 10.1111/1744-7917.13117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/17/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The ubiquitously expressed transmembrane enzyme Na,K-ATPase (NKA) is vital in maintaining functionality of cells. The association of α- and β-subunits is believed to be essential for forming a functional enzyme. In the large milkweed bug Oncopeltus fasciatus four α1-paralogs and four β-subunits exist that can associate into NKA complexes. This diversity raises the question of possible tissue-specific distribution and function. While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency, the functional importance of the β-subunits needed further investigation. We here characterize all four different β-subunits at the cellular, tissue, and whole organismal scales. A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes. The failure of ecdysis might be related to disrupted septate junction (SJ) formation, also reflected in β2-suppression-induced alteration in tracheal morphology. Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes. This possible standalone and structure-specific distribution of the β-subunits predicts further, yet unknown pump-independent functions. The different effects caused by β knockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.
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Affiliation(s)
- Marlena Herbertz
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Jennifer Lohr
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Christian Lohr
- Division of Neurophysiology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Susanne Dobler
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
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5
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Rohlfing K, Yue L, Franke S, Zeng C, Podsiadlowski L, Dobler S. When does the female bias arise? Insights from the sex determination cascade of a flea beetle with a strongly skewed sex ratio. Funct Integr Genomics 2023; 23:112. [PMID: 37000335 PMCID: PMC10066108 DOI: 10.1007/s10142-023-01023-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/03/2023] [Accepted: 03/09/2023] [Indexed: 04/01/2023]
Abstract
Reproduction-manipulating bacteria like Wolbachia can shift sex ratios in insects towards females, but skewed sex ratios may also arise from genetic conflicts. The flea beetle Altica lythri harbors three main mtDNA strains that are coupled to three different Wolbachia infections. Depending on the mtDNA types, the females produce either offspring with a balanced sex ratio or exclusively daughters. To obtain markers that can monitor when sex bias arises in the beetle's ontogeny, we elucidated the sex determination cascade of A. lythri. We established a RT-PCR method based on length variants of dsx (doublesex) transcripts to determine the sex of morphologically indistinguishable eggs and larvae. In females of one mtDNA type (HT1/HT1*) known to produce only daughters, male offspring were already missing at the egg stage while for females of another type (HT2), the dsx splice variants revealed a balanced sex ratio among eggs and larvae. Our data suggest that the sex determination cascade in A. lythri is initiated by maternally transmitted female-specific tra (transformer) mRNA as primary signal. This tra mRNA seems to be involved in a positive feedback loop that maintains the production of the female splice variant, as known for female offspring in Tribolium castaneum. The translation of the maternally transmitted female tra mRNA must be inhibited in male offspring, but the underlying primary genetic signal remains to be identified. We discuss which differences between the mtDNA types can influence sex determination and lead to the skewed sex ratio of HT1.
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Affiliation(s)
- Kim Rohlfing
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany.
| | - Lennart Yue
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Sebastian Franke
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Cen Zeng
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany
| | - Lars Podsiadlowski
- Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig, Bonn, Germany
| | - Susanne Dobler
- Institute of Animal Cell and Systems Biology, Universität Hamburg, Martin-Luther-King-Platz 3, D-20146, Hamburg, Germany.
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Mohammadi S, Özdemir Hİ, Ozbek P, Sumbul F, Stiller J, Deng Y, Crawford AJ, Rowland HM, Storz JF, Andolfatto P, Dobler S. Epistatic Effects Between Amino Acid Insertions and Substitutions Mediate Toxin resistance of Vertebrate Na+,K+-ATPases. Mol Biol Evol 2022; 39:6874786. [PMID: 36472530 PMCID: PMC9778839 DOI: 10.1093/molbev/msac258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022] Open
Abstract
The recurrent evolution of resistance to cardiotonic steroids (CTS) across diverse animals most frequently involves convergent amino acid substitutions in the H1-H2 extracellular loop of Na+,K+-ATPase (NKA). Previous work revealed that hystricognath rodents (e.g., chinchilla) and pterocliform birds (sandgrouse) have convergently evolved amino acid insertions in the H1-H2 loop, but their functional significance was not known. Using protein engineering, we show that these insertions have distinct effects on CTS resistance in homologs of each of the two species that strongly depend on intramolecular interactions with other residues. Removing the insertion in the chinchilla NKA unexpectedly increases CTS resistance and decreases NKA activity. In the sandgrouse NKA, the amino acid insertion and substitution Q111R both contribute to an augmented CTS resistance without compromising ATPase activity levels. Molecular docking simulations provide additional insight into the biophysical mechanisms responsible for the context-specific mutational effects on CTS insensitivity of the enzyme. Our results highlight the diversity of genetic substrates that underlie CTS insensitivity in vertebrate NKA and reveal how amino acid insertions can alter the phenotypic effects of point mutations at key sites in the same protein domain.
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Affiliation(s)
- Shabnam Mohammadi
- Molecular Evolutionary Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg 20146, Germany.,Max Planck Institute for Chemical Ecology, Research Group Predators and Toxic Prey, Jena 07745, Germany
| | | | - Pemra Ozbek
- Department of Bioengineering, Marmara University, Göztepe, İstanbul 34722, Turkey
| | - Fidan Sumbul
- INSERM, Aix-Marseille Université, Inserm, CNRS, Marseille 13009, France
| | - Josefin Stiller
- Villum Centre for Biodiversity Genomics, University of Copenhagen, Copenhagen 2100, Denmark
| | - Yuan Deng
- Villum Centre for Biodiversity Genomics, University of Copenhagen, Copenhagen 2100, Denmark.,BGI-Shenzhen, Shenzhen 518083, China
| | - Andrew J Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Hannah M Rowland
- Max Planck Institute for Chemical Ecology, Research Group Predators and Toxic Prey, Jena 07745, Germany
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York, NY
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg 20146, Germany
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7
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Mohammadi S, Herrera-Álvarez S, Yang L, Rodríguez-Ordoñez MDP, Zhang K, Storz JF, Dobler S, Crawford AJ, Andolfatto P. Constraints on the evolution of toxin-resistant Na,K-ATPases have limited dependence on sequence divergence. PLoS Genet 2022; 18:e1010323. [PMID: 35972957 DOI: 10.1101/2021.11.29.470343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/09/2022] [Accepted: 07/04/2022] [Indexed: 05/25/2023] Open
Abstract
A growing body of theoretical and experimental evidence suggests that intramolecular epistasis is a major determinant of rates and patterns of protein evolution and imposes a substantial constraint on the evolution of novel protein functions. Here, we examine the role of intramolecular epistasis in the recurrent evolution of resistance to cardiotonic steroids (CTS) across tetrapods, which occurs via specific amino acid substitutions to the α-subunit family of Na,K-ATPases (ATP1A). After identifying a series of recurrent substitutions at two key sites of ATP1A that are predicted to confer CTS resistance in diverse tetrapods, we then performed protein engineering experiments to test the functional consequences of introducing these substitutions onto divergent species backgrounds. In line with previous results, we find that substitutions at these sites can have substantial background-dependent effects on CTS resistance. Globally, however, these substitutions also have pleiotropic effects that are consistent with additive rather than background-dependent effects. Moreover, the magnitude of a substitution's effect on activity does not depend on the overall extent of ATP1A sequence divergence between species. Our results suggest that epistatic constraints on the evolution of CTS-resistant forms of Na,K-ATPase likely depend on a small number of sites, with little dependence on overall levels of protein divergence. We propose that dependence on a limited number sites may account for the observation of convergent CTS resistance substitutions observed among taxa with highly divergent Na,K-ATPases (See S1 Text for Spanish translation).
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
- Molecular Evolutionary Biology, Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
| | - Santiago Herrera-Álvarez
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Lu Yang
- Department of Ecology and Evolution, Princeton University, Princeton, New Jersey, United States of America
| | | | - Karen Zhang
- Department of Ecology and Evolution, Princeton University, Princeton, New Jersey, United States of America
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
| | - Andrew J Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York city, New York, United States of America
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8
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Mohammadi S, Herrera-Álvarez S, Yang L, Rodríguez-Ordoñez MDP, Zhang K, Storz JF, Dobler S, Crawford AJ, Andolfatto P. Constraints on the evolution of toxin-resistant Na,K-ATPases have limited dependence on sequence divergence. PLoS Genet 2022; 18:e1010323. [PMID: 35972957 PMCID: PMC9462791 DOI: 10.1371/journal.pgen.1010323] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/09/2022] [Accepted: 07/04/2022] [Indexed: 11/19/2022] Open
Abstract
A growing body of theoretical and experimental evidence suggests that intramolecular epistasis is a major determinant of rates and patterns of protein evolution and imposes a substantial constraint on the evolution of novel protein functions. Here, we examine the role of intramolecular epistasis in the recurrent evolution of resistance to cardiotonic steroids (CTS) across tetrapods, which occurs via specific amino acid substitutions to the α-subunit family of Na,K-ATPases (ATP1A). After identifying a series of recurrent substitutions at two key sites of ATP1A that are predicted to confer CTS resistance in diverse tetrapods, we then performed protein engineering experiments to test the functional consequences of introducing these substitutions onto divergent species backgrounds. In line with previous results, we find that substitutions at these sites can have substantial background-dependent effects on CTS resistance. Globally, however, these substitutions also have pleiotropic effects that are consistent with additive rather than background-dependent effects. Moreover, the magnitude of a substitution’s effect on activity does not depend on the overall extent of ATP1A sequence divergence between species. Our results suggest that epistatic constraints on the evolution of CTS-resistant forms of Na,K-ATPase likely depend on a small number of sites, with little dependence on overall levels of protein divergence. We propose that dependence on a limited number sites may account for the observation of convergent CTS resistance substitutions observed among taxa with highly divergent Na,K-ATPases (See S1 Text for Spanish translation). Individual amino acids within a protein work in concert to produce a functionally coherent structure that must be maintained as a protein diverges over time. Given this structure-function relationship, we expect the effects of new mutations to depend on amino acid states at other sites throughout the protein (i.e., background dependence) and that identical mutations will have more similar effects in more closely-related species, for which orthologous proteins will be less diverged. We tested this hypothesis by performing protein-engineering experiments on ATP1A, a protein that mediates resistance to toxins known as cardiotonic steroids (CTS), to reveal the extent of background-dependence across representative tetrapods. We find that, while the effects of mutations at two key sites implicated in CTS-resistance are indeed often background-dependent, the magnitude of these effects does not correlate with overall levels of ATP1A divergence. Our results instead suggest that background-dependent effects are determined by amino acid states at a small number of sites throughout the protein. Evolutionary constraints imposed by relatively few sites may explain the frequent occurrence of identical or similar CTS-resistance substitutions among ATP1A proteins of highly divergent animals (See S1 Text for Spanish translation).
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
- Molecular Evolutionary Biology, Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
| | - Santiago Herrera-Álvarez
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Lu Yang
- Department of Ecology and Evolution, Princeton University, Princeton, New Jersey, United States of America
| | | | - Karen Zhang
- Department of Ecology and Evolution, Princeton University, Princeton, New Jersey, United States of America
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institut für Zell- und Systembiologie der Tiere, Universität Hamburg, Hamburg, Germany
| | - Andrew J. Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York city, New York, United States of America
- * E-mail:
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9
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Herbertz M, Harder S, Schlüter H, Lohr C, Dobler S. Na,K-ATPase α1 and β-subunits show distinct localizations in the nervous tissue of the large milkweed bug. Cell Tissue Res 2022; 388:503-519. [PMID: 35332371 PMCID: PMC9110512 DOI: 10.1007/s00441-022-03580-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
The Na,K-ATPase (NKA) is an essential ion transporter and signaling molecule in all animal tissues and believed to consist at least one α and one ß-subunit to form a functional enzyme. In the large milkweed bug, Oncopeltus fasciatus, adaptation to dietary cardiac glycosides (CGs), which can fatally block the NKA, has resulted in gene duplications leading to four α1-subunits. These differ in sensitivity to CGs, but resistance trades off against ion pumping activity, thus influencing the α1-subunits’ suitability for specific tissues. Besides, O. fasciatus possesses four different ß-subunits that can alter the NKA's kinetics and should play an essential role in the formation of cellular junctions. Proteomic analyses revealed the distribution and composition of α1/ß-complexes in the nervous tissue of O. fasciatus. The highly CG-resistant, but less active α1B and the highly active, but less resistant α1C predominated in the nervous tissue and co-occurred with ß2 and ß3, partly forming larger complexes than just heterodimers. Immunohistochemical analyses provided a fine scale resolution of the subunits’ distribution in different morphological structures of the nervous tissue. This may suggest that α1 as well as ß-subunits occur in isolation without the other subunit, which contradicts the present understanding that the two types of subunits have to associate to form functional complexes. An isolated occurrence was especially prominent for ß3 and βx, the enigmatic fourth and N-terminally largely truncated ß-subunit. We hypothesize that dimerization of these ß-subunits plays a role in cell–cell contacts.
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Affiliation(s)
- Marlena Herbertz
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany.
| | - Sönke Harder
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Hartmut Schlüter
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Christian Lohr
- Institute of Cell and Systems Biology of Animals, Neurophysiology, Universität Hamburg, 20146, Hamburg, Germany
| | - Susanne Dobler
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany
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Mohammadi S, Yang L, Harpak A, Herrera-Álvarez S, Del Pilar Rodríguez-Ordoñez M, Peng J, Zhang K, Storz JF, Dobler S, Crawford AJ, Andolfatto P. Concerted evolution reveals co-adapted amino acid substitutions in Na +K +-ATPase of frogs that prey on toxic toads. Curr Biol 2021; 31:2530-2538.e10. [PMID: 33887183 DOI: 10.1016/j.cub.2021.03.089] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/12/2021] [Accepted: 03/26/2021] [Indexed: 11/18/2022]
Abstract
Although gene duplication is an important source of evolutionary innovation, the functional divergence of duplicates can be opposed by ongoing gene conversion between them. Here, we report on the evolution of a tandem duplication of Na+,K+-ATPase subunit α1 (ATP1A1) shared by frogs in the genus Leptodactylus, a group of species that feeds on toxic toads. One ATP1A1 paralog evolved resistance to toad toxins although the other retained ancestral susceptibility. Within species, frequent non-allelic gene conversion homogenized most of the sequence between the two copies but was counteracted by strong selection on 12 amino acid substitutions that distinguish the two paralogs. Protein-engineering experiments show that two of these substitutions substantially increase toxin resistance, whereas the additional 10 mitigate their deleterious effects on ATPase activity. Our results reveal how examination of neo-functionalized gene duplicate evolution can help pinpoint key functional substitutions and interactions with the genetic backgrounds on which they arise.
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Affiliation(s)
- Shabnam Mohammadi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Lu Yang
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Arbel Harpak
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | | | - Julie Peng
- Lewis-Sigler Institute, Princeton University, Princeton, NJ, USA
| | - Karen Zhang
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Universität Hamburg, Hamburg, Germany
| | - Andrew J Crawford
- Department of Biological Sciences, Universidad de los Andes, Bogotá 111711, Colombia.
| | - Peter Andolfatto
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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Silva A, Cisneros J, Pedroso C, Silva B, Borges Y, Novodworski J, Fernandez M, Dobler S. Características produtivas e qualitativas da sericultura no Brasil em sistemas de criação doméstico e não doméstico. ARCH ZOOTEC 2021. [DOI: 10.21071/az.v70i270.5466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objetivou-se avaliar a produção e qualidade de lagartas, pupas e casulos de bicho-da-seda em diferentes sistemas de criação no Brasil. Foram utilizadas 240 lagartas híbridas de Bombyx mori L. no terceiro instar, divididas em dois tipos de sistemas, o Doméstico e Não Doméstico, totalizando 120 animais por sistema. No Doméstico eram criadas em caixas de papel e manejo não tecnificado. En- quanto, no Não Doméstico eram criadas em barracão de criação sericícola, manejo assistenciados e tecnificados. Para realização de análises foram coletas de ambos os sistemas de criação, 40 lagartas no último dia do quinto ínstar e 60 casulos no terceiro dia após o início da construção dos mesmos. Foi observado melhor produção e qualidade para as medidas observadas nas lagartas (peso da lagarta e peso da glândula sericígena), nos casulos (peso do casulo, peso da casca sérica, largura e comprimento do casulo) e nas pupas (peso de pupas) para os bichos-da-seda criados no sistema Não Doméstico. Nenhuma diferença foi observada para casulos desclassificados, teor de seda liquida e pupas mortas. Entretanto, estes parâmetros impactam diretamente sobre o lucro do sericicultor. Com base nos resulta- dos obtidos, recomenda-se apostar na criação do bicho-da-seda no sistema Não Doméstico, onde se obtém casulos de melhor qualidade e com maior teor de seda líquida.
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12
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Kowalski P, Baum M, Körten M, Donath A, Dobler S. ABCB transporters in a leaf beetle respond to sequestered plant toxins. Proc Biol Sci 2020; 287:20201311. [PMID: 32873204 PMCID: PMC7542790 DOI: 10.1098/rspb.2020.1311] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022] Open
Abstract
Phytophagous insects can tolerate and detoxify toxic compounds present in their host plants and have evolved intricate adaptations to this end. Some insects even sequester the toxins for their defence. This necessitates specific mechanisms, especially carrier proteins that regulate uptake and transport to specific storage sites or protect sensitive tissues from noxious compounds. We identified three ATP-binding cassette subfamily B (ABCB) transporters from the transcriptome of the cardenolide-sequestering leaf beetle Chrysochus auratus and analysed their functional role in the sequestration process. These were heterologously expressed and tested for their ability to interact with various potential substrates: verapamil (standard ABCB substrate), the cardenolides digoxin (commonly used), cymarin (present in the species's host plant) and calotropin (present in the ancestral host plants). Verapamil stimulated all three ABCBs and each was activated by at least one cardenolide, however, they differed as to which they were activated by. While the expression of the most versatile transporter fits with a protective role in the blood-brain barrier, the one specific for cymarin shows an extreme abundance in the elytra, coinciding with the location of the defensive glands. Our data thus suggest a key role of ABCBs in the transport network needed for cardenolide sequestration.
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Affiliation(s)
- Paulina Kowalski
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Michael Baum
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Marcel Körten
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Alexander Donath
- ZFMK, Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere, Adenauerallee 160, 53113 Bonn, Germany
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
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13
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Kikuchi DW, Waldron SJ, Valkonen JK, Dobler S, Mappes J. Biased predation could promote convergence yet maintain diversity within Müllerian mimicry rings of Oreina leaf beetles. J Evol Biol 2020; 33:887-898. [PMID: 32202678 DOI: 10.1111/jeb.13620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/10/2020] [Accepted: 03/15/2020] [Indexed: 12/01/2022]
Abstract
Müllerian mimicry is a classic example of adaptation, yet Müller's original theory does not account for the diversity often observed in mimicry rings. Here, we aimed to assess how well classical Müllerian mimicry can account for the colour polymorphism found in chemically defended Oreina leaf beetles by using field data and laboratory assays of predator behaviour. We also evaluated the hypothesis that thermoregulation can explain diversity between Oreina mimicry rings. We found that frequencies of each colour morph were positively correlated among species, a critical prediction of Müllerian mimicry. Predators learned to associate colour with chemical defences. Learned avoidance of the green morph of one species protected green morphs of another species. Avoidance of blue morphs was completely generalized to green morphs, but surprisingly, avoidance of green morphs was less generalized to blue morphs. This asymmetrical generalization should favour green morphs: indeed, green morphs persist in blue communities, whereas blue morphs are entirely excluded from green communities. We did not find a correlation between elevation and coloration, rejecting thermoregulation as an explanation for diversity between mimicry rings. Biased predation could explain within-community diversity in warning coloration, providing a solution to a long-standing puzzle. We propose testable hypotheses for why asymmetric generalization occurs, and how predators maintain the predominance of blue morphs in a community, despite asymmetric generalization.
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Affiliation(s)
- David W Kikuchi
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.,Department of Biological and Environmental Sciences, Centre of Excellence in Evolutionary Research, University of Jyväskylä, Jyväskylä, Finland.,Wissenschaftskolleg zu Berlin, Berlin, Germany
| | - Samuel J Waldron
- Department of Biological and Environmental Sciences, Centre of Excellence in Evolutionary Research, University of Jyväskylä, Jyväskylä, Finland.,Molecular Evolutionary Biology, Department of Biology, Universität Hamburg, Hamburg, Germany
| | - Janne K Valkonen
- Department of Biological and Environmental Sciences, Centre of Excellence in Evolutionary Research, University of Jyväskylä, Jyväskylä, Finland
| | - Susanne Dobler
- Molecular Evolutionary Biology, Department of Biology, Universität Hamburg, Hamburg, Germany
| | - Johanna Mappes
- Department of Biological and Environmental Sciences, Centre of Excellence in Evolutionary Research, University of Jyväskylä, Jyväskylä, Finland.,Wissenschaftskolleg zu Berlin, Berlin, Germany
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14
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Abstract
AbstractInsects live in a dangerous world and may fall prey to a wide variety of predators, encompassing multiple taxa. As a result, selection may favour defences that are effective against multiple predator types, or target-specific defences that can reduce predation risk from particular groups of predators. Given the variation in sensory systems and hunting tactics, in particular between vertebrate and invertebrate predators, it is not always clear whether defences, such as chemical defences, that are effective against one group will be so against another. Despite this, the majority of research to date has focused on the role of a single predator species when considering the evolution of defended prey. Here we test the effectiveness of the chemical defences of the wood tiger moth, a species previously shown to have defensive chemicals targeted towards ants, against a common invertebrate predator: spiders. We presented both live moths and artificial prey containing their defensive fluids to female Trichonephila senegalensis and recorded their reactions. We found that neither of the moth’s two defensive fluids were able to repel the spiders, and confirmed that methoxypyrazines, a major component of the defences of both the wood tiger moth and many insect species, are ineffective against web-building spiders. Our results highlight the variability between predator taxa in their susceptibility to chemical defences, which can in part explain the vast variation in these chemicals seen in insects, and the existence of multiple defences in a single species.
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15
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Karageorgi M, Groen SC, Sumbul F, Pelaez JN, Verster KI, Aguilar JM, Hastings AP, Bernstein SL, Matsunaga T, Astourian M, Guerra G, Rico F, Dobler S, Agrawal AA, Whiteman NK. Genome editing retraces the evolution of toxin resistance in the monarch butterfly. Nature 2019; 574:409-412. [PMID: 31578524 PMCID: PMC7039281 DOI: 10.1038/s41586-019-1610-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 09/03/2019] [Indexed: 11/09/2022]
Abstract
Identifying the genetic mechanisms of adaptation requires the elucidation of links between the evolution of DNA sequence, phenotype, and fitness1. Convergent evolution can be used as a guide to identify candidate mutations that underlie adaptive traits2-4, and new genome editing technology is facilitating functional validation of these mutations in whole organisms1,5. We combined these approaches to study a classic case of convergence in insects from six orders, including the monarch butterfly (Danaus plexippus), that have independently evolved to colonize plants that produce cardiac glycoside toxins6-11. Many of these insects evolved parallel amino acid substitutions in the α-subunit (ATPα) of the sodium pump (Na+/K+-ATPase)7-11, the physiological target of cardiac glycosides12. Here we describe mutational paths involving three repeatedly changing amino acid sites (111, 119 and 122) in ATPα that are associated with cardiac glycoside specialization13,14. We then performed CRISPR-Cas9 base editing on the native Atpα gene in Drosophila melanogaster flies and retraced the mutational path taken across the monarch lineage11,15. We show in vivo, in vitro and in silico that the path conferred resistance and target-site insensitivity to cardiac glycosides16, culminating in triple mutant 'monarch flies' that were as insensitive to cardiac glycosides as monarch butterflies. 'Monarch flies' retained small amounts of cardiac glycosides through metamorphosis, a trait that has been optimized in monarch butterflies to deter predators17-19. The order in which the substitutions evolved was explained by amelioration of antagonistic pleiotropy through epistasis13,14,20-22. Our study illuminates how the monarch butterfly evolved resistance to a class of plant toxins, eventually becoming unpalatable, and changing the nature of species interactions within ecological communities2,6-11,15,17-19.
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Affiliation(s)
- Marianthi Karageorgi
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.,These authors contributed equally: Marianthi Karageorgi, Simon C. Groen
| | - Simon C. Groen
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.,Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY, USA.,These authors contributed equally: Marianthi Karageorgi, Simon C. Groen
| | - Fidan Sumbul
- LAI, U1067 Aix-Marseille Université, Inserm, CNRS, Marseille, France
| | - Julianne N. Pelaez
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Kirsten I. Verster
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Jessica M. Aguilar
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Amy P. Hastings
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Susan L. Bernstein
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Teruyuki Matsunaga
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Michael Astourian
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Geno Guerra
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Felix Rico
- LAI, U1067 Aix-Marseille Université, Inserm, CNRS, Marseille, France
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel, Universität Hamburg, Hamburg, Germany
| | - Anurag A. Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.,Department of Entomology, Cornell University, Ithaca, NY, USA
| | - Noah K. Whiteman
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.,Correspondence and requests for materials should be addressed to N.K.W.
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Dobler S, Wagschal V, Pietsch N, Dahdouli N, Meinzer F, Romey-Glüsing R, Schütte K. New ways to acquire resistance: imperfect convergence in insect adaptations to a potent plant toxin. Proc Biol Sci 2019; 286:20190883. [PMID: 31387508 PMCID: PMC6710594 DOI: 10.1098/rspb.2019.0883] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/17/2019] [Indexed: 12/22/2022] Open
Abstract
Evolution of insensitivity to the toxic effects of cardiac glycosides has become a model in the study of convergent evolution, as five taxonomic orders of insects use the same few similar amino acid substitutions in the otherwise highly conserved Na,K-ATPase α. We show here that insensitivity in pyrgomorphid grasshoppers evolved along a slightly divergent path. As in other lineages, duplication of the Na,K-ATPase α gene paved the way for subfunctionalization: one copy maintains the ancestral, sensitive state, while the other copy is resistant. Nonetheless, in contrast with all other investigated insects, the grasshoppers' resistant copy shows length variation by two amino acids in the first extracellular loop, the main part of the cardiac glycoside-binding pocket. RT-qPCR analyses confirmed that this copy is predominantly expressed in tissues exposed to the toxins, while the ancestral copy predominates in the nervous tissue. Functional tests with genetically engineered Drosophila Na,K-ATPases bearing the first extracellular loop of the pyrgomorphid genes showed the derived form to be highly resistant, while the ancestral state is sensitive. Thus, we report convergence in gene duplication and in the gene targets for toxin insensitivity; however, the means to the phenotypic end have been novel in pyrgomorphid grasshoppers.
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Affiliation(s)
- Susanne Dobler
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Vera Wagschal
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Niels Pietsch
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Nadja Dahdouli
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Fee Meinzer
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Renja Romey-Glüsing
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Hamburg, Germany
| | - Kai Schütte
- Animal Ecology and Conservation, Institute of Zoology, Universität Hamburg, Hamburg, Germany
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Meinzer F, Dobler S, Donath A, Lohr JN. Robust reference gene design and validation for expression studies in the large milkweed bug, Oncopeltus fasciatus, upon cardiac glycoside stress. Gene 2019; 710:66-75. [PMID: 31108166 DOI: 10.1016/j.gene.2019.05.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 04/06/2019] [Accepted: 05/13/2019] [Indexed: 11/18/2022]
Abstract
Despite its history as a developmental and evolutionary model organism, gene expression analysis in the large milkweed bug, Oncopeltus fasciatus, has rarely been explored using quantitative real-time PCR. The strength of this method depends greatly on the endogenous controls used for normalization, which are lacking for the milkweed bug system. Here, to fill in this gap in our knowledge, we validated the stability of a set of ten candidate reference genes identified from the O. fasciatus transcriptome, and did so upon exposure to a dietary toxin, a cardiac glycoside, and across four different exposure periods. To increase robustness against gDNA contaminants, genome resources were used to design intron-bridging primers. A comprehensive stability validation by the Bestkeeper, Normfinder, geNorm and comparative ΔCt methods identified ef1a and tubulin as the most stable genes across treatments and time points, whereas 18S rRNA was the most unstable. However, accounting for the temporal scale indicated that time point confined normalizers might enable higher quantification accuracy for treatment comparison. Overall this study demonstrates: (i) a robust RT-qPCR primer design approach is possible for non-model organisms where genome annotation is often incomplete, and (ii) the importance of detailed reference gene stability exploration in multifactorial experimental designs.
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Affiliation(s)
- Fee Meinzer
- Molekulare Evolutionsbiologie, Institut für Zoologie, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
| | - Susanne Dobler
- Molekulare Evolutionsbiologie, Institut für Zoologie, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Alexander Donath
- Zentrum für Molekulare Biodiversitätsforschung, Zoologisches Forschungsmuseum Alexander Koenig, 53113 Bonn, Germany
| | - Jennifer N Lohr
- Molekulare Evolutionsbiologie, Institut für Zoologie, Universität Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
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18
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Hundsdoerfer AK, Buchwalder K, O’Neill MA, Dobler S. Chemical ecology traits in an adaptive radiation: TPA-sensitivity and detoxification in Hyles and Hippotion (Sphingidae, Lepidoptera) larvae. CHEMOECOLOGY 2019. [DOI: 10.1007/s00049-018-0274-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Dobler S, Zintgraf V, Haberer W, Paul A. Ontogeny of Defensive Chemistry in Longitarsus Flea Beetles (Coleoptera, Chrysomelidae): More Protection for the Vulnerable Stages? J Chem Ecol 2018; 45:199-203. [PMID: 30167919 DOI: 10.1007/s10886-018-1010-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 10/28/2022]
Abstract
Several species of the flea beetles genus Longitarsus sequester pyrrolizidine alkaloids (PAs) from their host plants. Previous data demonstrated that PAs may be transferred from root-feeding larvae into the adult beetles. Here we compared the patterns and concentrations found in larvae and pupae of L. anchusae and L. echii with those of the roots of their respective hosts, Symphytum officinale and Echium vulgare (Boraginaceae). PA patterns and concentrations in the roots were complex and variable, whereas those in the larvae and pupae were simpler and more constant. In L. anchusae, intermedine and lycopsamine were the dominant PAs even if they could not be detected in the roots. In L. echii simpler, hydrolized PAs prevailed. Overall, the concentrations of total PAs of larvae and pupae were significantly higher than those of the roots the larvae had been feeding on. Larvae and pupae of both species also had considerably higher PA concentrations than determined previously for field collected beetles. Possibly the rather immobile juvenile stages enjoy a better protection by higher PA concentrations. On the other hand, we could not detect PAs in eggs of either species, indicating that transmission of appreciable amounts of PAs from mother to offspring does not occur.
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Affiliation(s)
- Susanne Dobler
- Institute of Biology I, University of Freiburg, Freiburg, Germany. .,Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany.
| | - Verena Zintgraf
- Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Wolf Haberer
- Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Andrea Paul
- Institute of Biology I, University of Freiburg, Freiburg, Germany
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20
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Affiliation(s)
- Christiane Bramer
- Johann-Friedrich-Blumenbach-Institut; Georg-August-Universität; Göttingen Germany
- Institut für Zoologie; Universität Hamburg; Hamburg Germany
| | | | - Susanne Dobler
- Institut für Zoologie; Universität Hamburg; Hamburg Germany
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21
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Lohr JN, Meinzer F, Dalla S, Romey-Glüsing R, Dobler S. The function and evolutionary significance of a triplicated Na,K-ATPase gene in a toxin-specialized insect. BMC Evol Biol 2017; 17:256. [PMID: 29246105 PMCID: PMC5732401 DOI: 10.1186/s12862-017-1097-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023] Open
Abstract
Background The Na,K-ATPase is a vital animal cell-membrane protein that maintains the cell’s resting potential, among other functions. Cardenolides, a group of potent plant toxins, bind to and inhibit this pump. The gene encoding the α-subunit of the pump has undergone duplication events in some insect species known to feed on plants containing cardenolides. Here we test the function of these duplicated gene copies in the cardenolide-adapted milkweed bug, Oncopeltus fasciatus, which has three known copies of the gene: α1A, α1B and α1C. Results Using RT-qPCR analyses we demonstrate that the α1C is highly expressed in neural tissue, where the pump is generally thought to be most important for neuron excitability. With the use of in vivo RNAi in adult bugs we found that α1C knockdowns suffered high mortality, where as α1A and α1B did not, supporting that α1C is most important for effective ion pumping. Next we show a role for α1A and α1B in the handling of cardenolides: expression results find that both copies are primarily expressed in the Malpighian tubules, the primary insect organ responsible for excretion, and when we injected either α1A or α1B knockdowns with cardenolides this proved fatal (whereas not in controls). Conclusions These results show that the Na,K-ATPα gene-copies have taken on diverse functions. Having multiple copies of this gene appears to have allowed the newly arisen duplicates to specialize on resistance to cardenolides, whereas the ancestral copy of the pump remains comparatively sensitive, but acts as a more efficient ion carrier. Interestingly both the α1A and α1B were required for cardenolide handling, suggesting that these two copies have separate and vital functions. Gene duplications of the Na,K-ATPase thus represent an excellent example of subfunctionalization in response to a new environmental challenge. Electronic supplementary material The online version of this article (10.1186/s12862-017-1097-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer N Lohr
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany. .,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, WC1E 6BT, London, UK.
| | - Fee Meinzer
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Safaa Dalla
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Renja Romey-Glüsing
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Susanne Dobler
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
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22
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Dalla S, Baum M, Dobler S. Substitutions in the cardenolide binding site and interaction of subunits affect kinetics besides cardenolide sensitivity of insect Na,K-ATPase. Insect Biochem Mol Biol 2017; 89:43-50. [PMID: 28866054 DOI: 10.1016/j.ibmb.2017.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/20/2017] [Accepted: 08/29/2017] [Indexed: 06/07/2023]
Abstract
Substitutions within the cardenolide target site of several insects' Na,K-ATPase α-subunits may confer resistance against toxic cardenolides. However, to which extent these substitutions alter the Na,K-ATPase's kinetic properties and how they interact with different β-subunits is not clear. The cardenolide-adapted milkweed bug Oncopeltus fasciatus possesses three paralogs of the α-subunit (A, B, and C) that differ in number and identity of resistance-conferring substitutions. We introduced these substitutions into the α-subunit of Drosophila melanogaster and combined them with the β-subunits Nrv2.2 and Nrv3. The substitutions Q111T-N122H-F786N-T797A (A-copy mimic) and Q111T-N122H-F786N (B-copy mimic) mediated high insensitivity to ouabain, yet they drastically lowered ATPase activity. Remarkably, the identity of the β-subunit was decisive and all α-subunits were less active when combined with Nrv3 than when combined with Nrv2.2. Both the substitutions and the co-expressed β-subunit strongly affected the enyzme's affinity for Na+ and K+. Na+ affinity was considerably higher for all enzymes expressed with nrv3 while expression with nrv2.2 mostly increased K+ affinity. Our results provide the first evidence that resistance against cardenolides comes at the cost of significantly altered kinetic properties of the Na,K-ATPase. The β-subunit can strongly modulate these properties but cannot fully compensate for the effect of the substitutions.
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Affiliation(s)
- Safaa Dalla
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
| | - Michael Baum
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
| | - Susanne Dobler
- Institute of Zoology, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany.
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23
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Petschenka G, Wagschal V, von Tschirnhaus M, Donath A, Dobler S. Convergently Evolved Toxic Secondary Metabolites in Plants Drive the Parallel Molecular Evolution of Insect Resistance. Am Nat 2017; 190:S29-S43. [DOI: 10.1086/691711] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Dobler S, Mardulyn P, Pasteels JM, Rowell-Rahier M. HOST-PLANT SWITCHES AND THE EVOLUTION OF CHEMICAL DEFENSE AND LIFE HISTORY IN THE LEAF BEETLE GENUS OREINA. Evolution 2017; 50:2373-2386. [DOI: 10.1111/j.1558-5646.1996.tb03625.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/1995] [Accepted: 06/20/1996] [Indexed: 11/29/2022]
Affiliation(s)
- Susanne Dobler
- Zoologisches Institut; Universität Basel; Rheinsprung 9 CH-4051 Basel Switzerland
- Laboratoire de Biologie Animale et Cellulaire; Université Libre de Bruxelles; 50 Av. F.D. Roosevelt B-1050 Bruxelles Belgium
| | - Patrick Mardulyn
- Laboratoire de Biologie Animale et Cellulaire; Université Libre de Bruxelles; 50 Av. F.D. Roosevelt B-1050 Bruxelles Belgium
| | - Jacques M. Pasteels
- Laboratoire de Biologie Animale et Cellulaire; Université Libre de Bruxelles; 50 Av. F.D. Roosevelt B-1050 Bruxelles Belgium
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Mohammadi S, Savitzky AH, Lohr J, Dobler S. Toad toxin-resistant snake ( Thamnophis elegans ) expresses high levels of mutant Na + /K + -ATPase mRNA in cardiac muscle. Gene 2017; 614:21-25. [DOI: 10.1016/j.gene.2017.02.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/26/2017] [Accepted: 02/24/2017] [Indexed: 10/25/2022]
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Groen SC, LaPlante ER, Alexandre NM, Agrawal AA, Dobler S, Whiteman NK. Multidrug transporters and organic anion transporting polypeptides protect insects against the toxic effects of cardenolides. Insect Biochem Mol Biol 2017; 81:51-61. [PMID: 28011348 PMCID: PMC5428987 DOI: 10.1016/j.ibmb.2016.12.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/16/2016] [Accepted: 12/19/2016] [Indexed: 05/10/2023]
Abstract
In the struggle against dietary toxins, insects are known to employ target site insensitivity, metabolic detoxification, and transporters that shunt away toxins. Specialized insects across six taxonomic orders feeding on cardenolide-containing plants have convergently evolved target site insensitivity via specific amino acid substitutions in the Na/K-ATPase. Nonetheless, in vitro pharmacological experiments have suggested a role for multidrug transporters (Mdrs) and organic anion transporting polypeptides (Oatps), which may provide a basal level of protection in both specialized and non-adapted insects. Because the genes coding for these proteins are evolutionarily conserved and in vivo genetic evidence in support of this hypothesis is lacking, here we used wildtype and mutant Drosophila melanogaster (Drosophila) in capillary feeder (CAFE) assays to quantify toxicity of three chemically diverse, medically relevant cardenolides. We examined multiple components of fitness, including mortality, longevity, and LD50, and found that, while the three cardenolides each stimulated feeding (i.e., no deterrence to the toxin), all decreased lifespan, with the most apolar cardenolide having the lowest LD50 value. Flies showed a clear non-monotonic dose response and experienced high levels of toxicity at the cardenolide concentration found in plants. At this concentration, both Mdr and Oatp knockout mutant flies died more rapidly than wildtype flies, and the mutants also experienced more adverse neurological effects on high-cardenolide-level diets. Our study further establishes Drosophila as a model for the study of cardenolide pharmacology and solidifies support for the hypothesis that multidrug and organic anion transporters are key players in insect protection against dietary cardenolides.
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Affiliation(s)
- Simon C Groen
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
| | - Erika R LaPlante
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA; Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA
| | - Nicolas M Alexandre
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA; Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA
| | - Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA; Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
| | - Noah K Whiteman
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA; Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA.
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Dalla S, Dobler S. Gene duplications circumvent trade-offs in enzyme function: Insect adaptation to toxic host plants. Evolution 2016; 70:2767-2777. [DOI: 10.1111/evo.13077] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 01/20/2023]
Affiliation(s)
- Safaa Dalla
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
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Bramer C, Dobler S, Deckert J, Stemmer M, Petschenka G. Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae). Proc Biol Sci 2015; 282:20142346. [PMID: 25808891 PMCID: PMC4389604 DOI: 10.1098/rspb.2014.2346] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/03/2015] [Indexed: 11/12/2022] Open
Abstract
Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na(+)/K(+)-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na(+)/K(+)-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na(+)/K(+)-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families.
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Affiliation(s)
- Christiane Bramer
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - Susanne Dobler
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - Jürgen Deckert
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany
| | | | - Georg Petschenka
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, NY 14853, USA
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29
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Dalla S, Swarts HGP, Koenderink JB, Dobler S. Amino acid substitutions of Na,K-ATPase conferring decreased sensitivity to cardenolides in insects compared to mammals. Insect Biochem Mol Biol 2013; 43:1109-1115. [PMID: 24121093 DOI: 10.1016/j.ibmb.2013.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/23/2013] [Accepted: 09/27/2013] [Indexed: 06/02/2023]
Abstract
Mutagenesis analyses and a recent crystal structure of the mammalian Na,K-ATPase have identified amino acids which are responsible for high affinity binding of cardenolides (such as ouabain) which at higher doses block the enzyme in the phosphorylated state. Genetic analysis of the Na,K-ATPase of insects adapted to cardenolides in their food plants revealed that some species possess substitutions which confer strongly increased resistance to ouabain in the mammalian enzyme such as the substitution T797A or combined substitutions at positions 111 and 122. To test for the effect of these mutations against the background of insect Na,K-ATPase, we here expressed the ouabain sensitive Na,K-ATPase α-subunit of Drosophila melanogaster together with the β-subunit Nrv3 in baculovirus-infected Sf9 cells and introduced the substitutions N122H, T797A, Q111T-N122H, Q111V-N122H, all of which have been observed in cardenolide-adapted insects. While all constructs showed similar expression levels, ouabain affinity of mutated Na,K-ATPases was reduced compared to the wild-type fly enzyme. Ouabain sensitivity of the ATPase activity in inhibition assays was significantly decreased by all mutations, yet whereas the IC₅₀ for the single mutations of N122H (61.0 μM) or T797A (63.3 μM) was increased roughly 250-fold relative to the wild-type (0.24 μM), the double mutations of Q111V-N122H (IC₅₀ 550 μM) and Q111T-N122H (IC₅₀ 583 μM) proved to be still more effective yielding a 2.250-fold increased resistance to ouabain. The double mutations identified in cardenolide-adapted insects are more effective in reducing ouabain sensitivity of the enzyme than those found naturally in the rat Na,K-ATPase (Q111R-N122D) or in mutagenesis screens of the mammalian enzyme. Obviously, the intense selection pressure on cardenolide exposed insects has resulted in very efficient substitutions that decrease cardenolide sensitivity extremely.
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Affiliation(s)
- Safaa Dalla
- Molecular Evolutionary Biology, Biocenter Grindel, Universität Hamburg, Martin-Luther-King Pl. 3, 20146 Hamburg, Germany
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Dobler S, Rowell-Rahier M. Production of cardenolides versus sequestration of pyrrolizidine alkaloids in larvae ofOreina species (Coleoptera, Chrysomelidae). J Chem Ecol 2013; 20:555-68. [PMID: 24242111 DOI: 10.1007/bf02059597] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/1993] [Accepted: 10/18/1993] [Indexed: 10/25/2022]
Abstract
Adult leaf beetles of the genusOreina are known to be defended either by autogenously produced cardenolides or by pyrrolizidine alkaloids (PAs) sequestered from the food plant, or both. In this paper we analyze larvae of differentOreina species and show that the larvae contain the same defensive toxins as the adults in quantities similar to those released in the adults' secretion. Both classes of toxins are found in the body and hemolymph of the larvae, despite their different origins and later distribution in the adults. Larvae of sequestering species differed in their PA patterns, even though they fed on the same food plants. The concentration in first-instar larvae of a PA-sequestering species was similar to that in fourth-instar larvae. In all stages examined, the amount of PAs per larva did not greatly exceed the estimated uptake of one day. Eggs of two oviparous species contained large concentrations of the adult's toxins, while neonates of a sequestering larviparous species had no PAs.
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Affiliation(s)
- S Dobler
- Zoologisches Institut der Universität Basel, Rheinsprung 9, 4051, Basel, Switzerland
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31
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Jäckel R, Mora D, Dobler S. Evidence for selective sweeps byWolbachiainfections: phylogeny ofAlticaleaf beetles and their reproductive parasites. Mol Ecol 2013; 22:4241-4255. [DOI: 10.1111/mec.12389] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Regina Jäckel
- Zoological Institute; University of Hamburg; Martin-Luther-King-Platz 3 20146 Hamburg Germany
| | - Diana Mora
- Zoological Institute; University of Hamburg; Martin-Luther-King-Platz 3 20146 Hamburg Germany
| | - Susanne Dobler
- Zoological Institute; University of Hamburg; Martin-Luther-King-Platz 3 20146 Hamburg Germany
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32
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Petschenka G, Fandrich S, Sander N, Wagschal V, Boppré M, Dobler S. STEPWISE EVOLUTION OF RESISTANCE TO TOXIC CARDENOLIDES VIA GENETIC SUBSTITUTIONS IN THE NA+/K+-ATPASE OF MILKWEED BUTTERFLIES (LEPIDOPTERA: DANAINI). Evolution 2013; 67:2753-61. [DOI: 10.1111/evo.12152] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/15/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Georg Petschenka
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Steffi Fandrich
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Nils Sander
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Vera Wagschal
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
| | - Michael Boppré
- Forstzoologisches Institut; Albert-Ludwigs-Universität; 79085; Freiburg; Germany
| | - Susanne Dobler
- Biozentrum Grindel; Martin-Luther-King-Platz 3; 20146; Hamburg; Germany
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33
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Petschenka G, Pick C, Wagschal V, Dobler S. Functional evidence for physiological mechanisms to circumvent neurotoxicity of cardenolides in an adapted and a non-adapted hawk-moth species. Proc Biol Sci 2013; 280:20123089. [PMID: 23516239 DOI: 10.1098/rspb.2012.3089] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Because cardenolides specifically inhibit the Na(+)K(+)-ATPase, insects feeding on cardenolide-containing plants need to circumvent this toxic effect. Some insects such as the monarch butterfly rely on target site insensitivity, yet other cardenolide-adapted lepidopterans such as the oleander hawk-moth, Daphnis nerii, possess highly sensitive Na(+)K(+)-ATPases. Nevertheless, larvae of this species and the related Manduca sexta are insensitive to injected cardenolides. By radioactive-binding assays with nerve cords of both species, we demonstrate that the perineurium surrounding the nervous tissue functions as a diffusion barrier for a polar cardenolide (ouabain). By contrast, for non-polar cardenolides such as digoxin an active efflux carrier limits the access to the nerve cord. This barrier can be abolished by metabolic inhibitors and by verapamil, a specific inhibitor of P-glycoproteins (PGPs). This supports that a PGP-like transporter is involved in the active cardenolide-barrier of the perineurium. Tissue specific RT-PCR demonstrated expression of three PGP-like genes in hornworm nerve cords, and immunohistochemistry further corroborated PGP expression in the perineurium. Our results thus suggest that the lepidopteran perineurium serves as a diffusion barrier for polar cardenolides and provides an active barrier for non-polar cardenolides. This may explain the high in vivo resistance to cardenolides observed in some lepidopteran larvae, despite their highly sensitive Na(+)K(+)-ATPases.
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Affiliation(s)
- Georg Petschenka
- Molekulare Evolutionsbiologie, Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
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Pankoke H, Bowers MD, Dobler S. The interplay between toxin-releasing β-glucosidase and plant iridoid glycosides impairs larval development in a generalist caterpillar, Grammia incorrupta (Arctiidae). Insect Biochem Mol Biol 2012; 42:426-434. [PMID: 22446106 DOI: 10.1016/j.ibmb.2012.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 02/28/2012] [Accepted: 02/29/2012] [Indexed: 05/31/2023]
Abstract
Herbivores with polyphagous feeding habits must cope with a diet that varies in quality. One of the most important sources of this variation in host plant suitability is plant secondary chemistry. We examined how feeding on plants containing one such group of compounds, the iridoid glycosides, might affect the growth and enzymatic activity in a polyphagous caterpillar that feeds on over 80 plant species in 50 different families. Larvae of the polyphagous arctiid, Grammia incorrupta, were reared exclusively on one of two plant species, one of which contains iridoid glycosides (Plantago lanceolata, Plantaginaceae) while the other does not (Taraxacum officinale, Asteraceae). Larval weight was measured on the two host plants, and midgut homogenates of last instar larvae were then assayed for activity and kinetic properties of β-glucosidases, using both a standard substrate, 4-nitrophenyl-β-D-glucose (NPβGlc), and the iridoid glycoside aucubin, one of the two main iridoid glycosides in P. lanceolata. Larvae feeding on P. lanceolata weighed significantly less and developed more slowly compared to larvae on T. officinale. While the larval midgut β-glucosidase activity determined with NPβGlc was significantly decreased when fed on P. lanceolata, aucubin was substantially hydrolyzed and the larval β-glucosidase activity towards both substrates correlated negatively with larval weight. Our results demonstrate that host plants containing high concentrations of iridoid glycosides have a negative impact on larval development of this generalist insect herbivore. This is most likely due to the hydrolysis of plant glycosides in the larval midgut which results in the release of toxic aglycones. Linking the reduced larval weight to the toxin-releasing action of an iridoid glycoside cleaving β-glucosidase, our results thus support the detoxification limitation hypothesis, suggesting fitness costs for the larvae feeding solely on P. lanceolata. Thus, in addition to the adaptive regulation of midgut β-glucosidase activity, host plant switching as a behavioral adaptation might be a prerequisite for generalist herbivores that allows them to circumvent the negative effects of plant secondary compounds.
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Affiliation(s)
- Helga Pankoke
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
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35
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Petschenka G, Offe JK, Dobler S. Physiological screening for target site insensitivity and localization of Na(+)/K(+)-ATPase in cardenolide-adapted Lepidoptera. J Insect Physiol 2012; 58:607-12. [PMID: 22343317 DOI: 10.1016/j.jinsphys.2011.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 12/20/2011] [Accepted: 12/20/2011] [Indexed: 05/25/2023]
Abstract
Cardenolides are toxic plant compounds which specifically inhibit Na(+)/K(+)-ATPase, an animal enzyme which is essential for many physiological processes, such as the generation of action potentials. Several adapted insects feeding on cardenolide-containing plants sequester these toxins for their own defence. Some of these insects were shown to possess Na(+)/K(+)-ATPases with a reduced sensitivity towards cardenolides (target site insensitivity). In the present study we screened five species of arctiid moths feeding on cardenolide-containing plants for target site insensitivity towards cardenolides using an in vitro enzyme assay. The derived dose response curves of the respective Na(+)/K(+)-ATPases were compared to the insensitive Na(+)/K(+)-ATPase of the monarch butterfly (Danaus plexippus). Na(+)/K(+)-ATPases of all arctiid species tested were highly sensitive to ouabain, a water-soluble cardenolide which is most widely used in laboratory studies. Nevertheless, we detected substantial amounts of cardenolides in the haemolymph of two of the arctiid species. In caterpillars of the sequestering arctiid Empyreuma pugione and of D. plexippus we localized Na(+)/K(+)-ATPase by immunohistochemistry and western blot (in D. plexippus). Both techniques revealed strong expression of the enzyme in the nervous tissue and indicated weak expression or even absence in other tissues tested. We conclude that instead of target site insensitivity the investigated arctiid species use a different strategy to tolerate cardenolides. Most plausibly, the perineurium surrounding the nervous tissue functions as a barrier which prevents cardenolides from reaching Na(+)/K(+)-ATPase in the ventral nerve cord.
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Affiliation(s)
- Georg Petschenka
- Biozentrum Grindel Molekulare Evolutionsbiologie, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
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36
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Baden CU, Franke S, Dobler S. Differing patterns of sequestration of iridoid glycosides in the Mecininae (Coleoptera, Curculionidae). CHEMOECOLOGY 2012. [DOI: 10.1007/s00049-012-0103-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dobler S, Petschenka G, Pankoke H. Coping with toxic plant compounds--the insect's perspective on iridoid glycosides and cardenolides. Phytochemistry 2011; 72:1593-1604. [PMID: 21620425 DOI: 10.1016/j.phytochem.2011.04.015] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 03/30/2011] [Accepted: 04/20/2011] [Indexed: 05/27/2023]
Abstract
Specializing on host plants with toxic secondary compounds enforces specific adaptation in insect herbivores. In this review, we focus on two compound classes, iridoid glycosides and cardenolides, which can be found in the food plants of a large number of insect species that display various degrees of adaptation to them. These secondary compounds have very different modes of action: Iridoid glycosides are usually activated in the gut of the herbivores by β-glucosidases that may either stem from the food plant or be present in the gut as standard digestive enzymes. Upon cleaving, the unstable aglycone is released that unspecifically acts by crosslinking proteins and inhibiting enzymes. Cardenolides, on the other hand, are highly specific inhibitors of an essential ion carrier, the sodium pump. In insects exposed to both kinds of toxins, carriers either enabling the safe storage of the compounds away from the activating enzymes or excluding the toxins from sensitive tissues, play an important role that deserves further analysis. To avoid toxicity of iridoid glycosides, repression of activating enzymes emerges as a possible alternative strategy. Cardenolides, on the other hand, may lose their toxicity if their target site is modified and this strategy has evolved multiple times independently in cardenolide-adapted insects.
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Affiliation(s)
- Susanne Dobler
- Biocenter Grindel, Hamburg University, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
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38
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39
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Pankoke H, Bowers MD, Dobler S. Influence of iridoid glycoside containing host plants on midgut β-glucosidase activity in a polyphagous caterpillar, Spilosoma virginica Fabricius (Arctiidae). J Insect Physiol 2010; 56:1907-1912. [PMID: 20727899 DOI: 10.1016/j.jinsphys.2010.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 08/11/2010] [Accepted: 08/12/2010] [Indexed: 05/29/2023]
Abstract
Iridoid glycosides are secondary plant compounds that have deterrent, growth reducing or even toxic effects on non-adapted herbivorous insects. To investigate the effects of iridoid glycoside containing plants on the digestive metabolism of a generalist herbivore, larvae of Spilosoma virginica (Lepidoptera: Arctiidae) were reared on three plant species that differ in their secondary plant chemistry: Taraxacum officinale (no iridoid glycosides), Plantago major (low iridoid glycoside content), and P. lanceolata (high iridoid glycoside content). Midguts of fifth instar larvae were assayed for the activity and kinetic properties of β-glucosidase using different substrates. Compared to the larvae on T. officinale, the β-glucosidase activity of larvae feeding on P. lanceolata was significantly lower measured with 4-nitrophenyl-β-d-glucopyranoside. Using the iridoid glycoside aucubin as a substrate, we did not find differences in the β-glucosidase activity of the larvae reared on the three plants. Heat inactivation experiments revealed the existence of a heat-labile and a more heat-stable β-glucosidase with similar Michaelis constants for 4-nitrophenyl-β-d-glucopyranoside. We discuss possible mechanisms leading to the observed decrease of β-glucosidase activity for larvae reared on P. lanceolata and its relevance for generalist herbivores in adapting to iridoid glycoside containing plant species and their use as potential host plants.
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Affiliation(s)
- Helga Pankoke
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
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40
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Kelley ST, Dobler S. Comparative analysis of microbial diversity in Longitarsus flea beetles (Coleoptera: Chrysomelidae). Genetica 2010; 139:541-50. [PMID: 20844936 DOI: 10.1007/s10709-010-9498-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 09/04/2010] [Indexed: 02/06/2023]
Abstract
Herbivorous beetles comprise a significant fraction of eukaryotic biodiversity and their plant-feeding adaptations make them notorious agricultural pests. Despite more than a century of research on their ecology and evolution, we know little about the diversity and function of their symbiotic microbial communities. Recent culture-independent molecular studies have shown that insects possess diverse gut microbial communities that appear critical for their survival. In this study, we combined culture-independent methods and high-throughput sequencing strategies to perform a comparative analysis of Longitarsus flea-beetles microbial community diversity (MCD). This genus of beetle herbivores contains host plant specialists and generalists that feed on a diverse array of toxic plants. Using a deep-sequencing approach, we characterized the MCD of eleven Longitarsus species across the genus, several of which represented independent shifts to the same host plant families. Database comparisons found that Longitarsus-associated microbes came from two habitat types: insect guts and the soil rhizosphere. Statistical clustering of the Longitarsus microbial communities found little correlation with the beetle phylogeny, and uncovered discrepancies between bacterial communities extracted directly from beetles and those from frass. A Principal Coordinates Analysis also found some correspondence between beetle MCD and host plant family. Collectively, our data suggest that environmental factors play a dominant role in shaping Longitarsus MCD and that the root-feeding beetle larvae of these insects are inoculated by soil rhizosphere microbes. Future studies will investigate MCD of select Longitarsus species across their geographic ranges and explore the connection between the soil rhizosphere and the beetle MCD.
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Affiliation(s)
- Scott T Kelley
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
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Peterson MA, Dobler S, Larson EL, Juárez D, Schlarbaum T, Monsen KJ, Francke W. Profiles of cuticular hydrocarbons mediate male mate choice and sexual isolation between hybridising Chrysochus (Coleoptera: Chrysomelidae). CHEMOECOLOGY 2007. [DOI: 10.1007/s00049-007-0366-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Narberhaus I, Papke U, Theuring C, Beuerle T, Hartmann T, Dobler S. Direct Evidence for Membrane Transport of Host-Plant-Derived Pyrrolizidine Alkaloid N-Oxides in Two Leaf Beetle Genera. J Chem Ecol 2004; 30:2003-22. [PMID: 15609833 DOI: 10.1023/b:joec.0000045591.26364.72] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The chrysomelid leaf beetles Longitarsus jacobaeae, Oreina cacaliae, and O. speciosissima sequester pyrrolizidine alkaloids from their asteracean host plants and store them as nontoxic N-oxides. Previous analyses showed that Longitarsus is able to N-oxidize protoxic tertiary PAs, but did not resolve in which form N-oxides are taken up. For Oreina, beetles seem able to directly transmit the polar PA N-oxides from the gut into the hemolymph and prevent any reduction of them in the gut yielding protoxic free bases. Here, we confirm the predicted direct uptake of PAs as N-oxides by Oreina, and elucidate the situation for Longitarsus by applying double-labeled [14C]senecionine [18O]N-oxide as tracer. The beetles were fed with the tracer and subsequently senecionine N-oxide was recovered from the defensive secretions (Oreina) and beetle extracts (Longitarsus), purified by HPLC, and submitted to ESI-MS, GC-MS, and analysis of the specific radioactivity. The 18O-label is retained without any loss in the labeled senecionine N-oxide recovered from the two Oreina species. Analysis of the Longitarsus experiment was complicated by a contamination of the HPLC-purified senecionine N-oxide with a second compound, identified as a dihydrosenecionine N-oxide by high-resolution CID analysis. The dihydrosenecionine N-oxide, probably the 15,20-dihydro derivative, constitutes a major idiosyncratic senecionine metabolite present in the beetle. The recovered senecionine N-oxide retained 74% 18O-label. The remaining 25% is mostly due to loss of 18O by reduction and subsequent re-N-oxidation. The experiments confirm for both beetle genera a direct uptake of the polar nontoxic PA N-oxides, which requires specific membrane carriers. Accumulation of detrimental free base PA is prevented by glucosylation (Oreina) or N-oxidation (Longitarsus).
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Affiliation(s)
- Ingo Narberhaus
- Biozentrum Grindel und Zoologisches Museum, Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
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Narberhaus I, Dobler S, Theuring C, Hartmann T. Time course of pyrrolizidine alkaloid sequestration in Longitarsus flea beetles (Coleoptera, Chrysomelidae). CHEMOECOLOGY 2004. [DOI: 10.1007/s00049-003-0254-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Herbivores that feed on toxic plants must overcome plant defenses and occasionally may even benefit from them. The current challenge is to understand how herbivores evolve the necessary physiological adaptations and which changes at the molecular level are involved. In this context we studied the leaf beetles genus Chrysochus (Coleoptera, Chrysomelidae). Two species of this genus, C. auratus and C. cobaltinus, feed on plants that contain toxic cardenolides. These beetles not only avoid poisoning by the toxin but also use it for their own defense against predators. All other Chrysochus species feed on plants that are devoid of cardenolides. The most important active principle of cardenolides is their capacity to bind to and thereby block the ubiquitous Na(+)/K(+)-ATPase responsible for maintaining cellular potentials. By analyzing the DNA sequence of the putative ouabain-binding site of the alpha-subunit of the Na(+)/K(+)-ATPase gene of Chrysochus and its close relatives feeding on plants with or without cardenolides, we here trace the evolution of cardenolide insensitivity in this group of beetles. The most interesting difference among the sequences involves the amino acid at position 122. Whereas all species that do not encounter cardenolides have an asparagine in this position, both Chrysochus species that feed on cardenolide plants have a histidine instead. This single amino acid substitution has already been shown to confer cardenolide insensitivity in the monarch butterfly. A mtDNA-based phylogeny corroborates the hypothesis that the asparagine at position 122 of the alpha-subunit of the Na(+)/K(+)-ATPase gene as observed in Drosophila and other insects is the plesiomorphic condition in this group of leaf beetles. The later host-plant switch to cardenolide-containing plants in the common ancestor of C. auratus and C. cobaltinus coincides with the exchange of the asparagine for a histidine in the ouabain binding site.
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Narberhaus I, Theuring C, Hartmann T, Dobler S. Uptake and metabolism of pyrrolizidine alkaloids in Longitarsus flea beetles (Coleoptera: Chrysomelidae) adapted and non-adapted to alkaloid-containing host plants. J Comp Physiol B 2003; 173:483-91. [PMID: 12802610 DOI: 10.1007/s00360-003-0356-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2003] [Indexed: 11/28/2022]
Abstract
Several Longitarsus flea beetle species sequester pyrrolizidine alkaloids acquired from their Asteraceae and Boraginaceae host plants. We carried out feeding and injection experiments using radioactively labeled pyrrolizidine alkaloids to investigate the physiological mechanisms of uptake, metabolism and storage of alkaloids in adult beetles. We examined six Longitarsus species belonging to different phylogenetic clades in a comparative approach. All species that accepted pyrrolizidine alkaloids in a preceding food choice study showed the ability both to store pyrrolizidine alkaloid N-oxides and to metabolize tertiary pyrrolizidine alkaloids into their N-oxides. Regardless of whether the beetles' natural host plants contain pyrrolizidine alkaloids or not, these species were found to possess an oxidizing enzyme. This oxygenase appears to be specific to pyrrolizidine alkaloids: [3H]Atropine and [14C]nicotine, two alkaloids not related to pyrrolizidine alkaloids, were neither stored nor N-oxidized by any of the tested species. One species, L. australis, that strictly avoids pyrrolizidine alkaloids behaviorally, exhibited a lack of adaptations to pyrrolizidine alkaloids on a physiological level as well. After injection of tertiary [14C]senecionine, beetles of this species neither N-oxidized nor stored the compounds, in contrast to L. jacobaeae, an adapted species that underwent the same treatment. L. jacobaeae demonstrated the same efficiency in N-oxidation and storage when fed or injected with tertiary [14C]senecionine.
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Affiliation(s)
- I Narberhaus
- Zoologisches Institut und Museum, Universität Hamburg, Martin-Luther-King Platz 3, 20146, Hamburg, Germany.
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Scherer PA, Dobler S, Rohardt S, Loock R, Büttner B, Nöldeke P, Brettschuh A. Continuous biogas production from fodder beet silage as sole substrate. Water Sci Technol 2003; 48:229-233. [PMID: 14531447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Since April 2000 a two-step anaerobic plant with two subsequent 500 m3 reactors has been producing biogas from fodder beet silage (pH 3.4-4.1) as the sole substrate. The plant is located at Kirchlengern near Bielefeld, Germany. Initially the reactors were inoculated with swine manure at 37 degrees C. After a start-up phase the process was sustained at pH 7.5-8.0 by feeding the silage as sole substrate with an HRT of about 55 d twice a day. Parallel to the biogas plant at Kirchlengern four one-step laboratory reactors were continuously driven at temperatures of 37 degrees C, 45 degrees C, 60 degrees C and 65 degrees C. They were fed with the same silage, but only once per day (one impulse). The organic loading rate (OLR) was adjusted to 3.9 g volatile solids (VS)/(l*d) with a concomitant hydraulic retention time (HRT) of 27 d. There was no problem with starting the reactors, but after 86 days the volumetric gas production of the 65 degrees C reactor ceased and a high amount of approximately 65 mM propionate could be determined. By decreasing the temperature down to 60 degrees C a stable reactor performance was recovered for a period of at least 600 further days. Interestingly microscopic analyses revealed that the morphology of methanogenic bacteria in the 60 degrees C was quite different from the 37 and 45 degrees C reactor exhibiting only rodlike methanogens whereas at 37 degrees C coccoid morphotypes besides rodlike methanogens were dominant. In a 55 degrees C reactor (separate experiment) a mixture of coccoid and rodlike methanogens established. During impulse feeding with 3.9 g (VS)/(l*d) it was observed that the quickest recovery of gas production, the pH, CH4 and CO2 content as well as the redox value could be observed at 37 degrees C or at 45 degrees C. Recovery of 75% gas volume (related to the value before or after impulse feeding) was obtained after 5.5 and 7.5 h of feeding time point whereas the 60 degrees C reactor needed 16 h. Slight significant differences were seen in the spectrum of volatile fatty acids (VFA) reaching at 37 degrees or 45 degrees C its maximum with 10-30 mM total VFA at 2-3 h after feeding. After this the VFA level declined to nearly zero (except for the 60 degrees C reactor). Therefore the 37 degrees C reactor was favoured. A double experiment with a second 37 degrees C reactor was started by a somewhat different inoculation procedure from the remaining 3 reactors, but revealed similar results. An impulse feeding experiment with a very high OLR of 16.5 g (VS)/(l*d) lasting 1 week offered a stable reactor performance with a peak GPR of up to 24 l/(l reactor *d) and an HRT of 5.45d. Therefore a long term operation with an HRT of only 7.5 days and an OLR of 12 g (VS)/(l*d) should be possible. By increasing the temperature no significantly different specific gas production rates and methane yields could be observed, e.g. it gave 600-7001 biogas from 1 kg VS. The corresponding methane content ranged between 62-64%. With a methane content of 63 +/- 1% a yield of 40.1 +/- 2 m3 methane/ton fresh fodder beet silage was obtained.
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Affiliation(s)
- P A Scherer
- Research Centre of Environmental Bioengineering and Applied Biotechnology, University of Applied Sciences, Hamburg.
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Cohen B, Dobler S, Sauron B, Hazan A, Peytral C, Fombeur JP. Comparison between caloric and canal impulse rotatory test. Acta Otorhinolaryngol Belg 2002; 56:73-6. [PMID: 11894634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
It has been suggested that the rotatory test using videosnystagmoscopy can also be applied for identification of vestibular canal paresis. In this study, we test this hypothesis by comparing the results of a canal impulse rotatory test with those of the caloric test using the method described by Freyss. Our study indicates that only in 38% of all tested patients, the same results between the two tests have been obtained. Furthermore, which the group with abnormal findings is observed separately, in 24% patients only these two test methods lead to the same results. Consequently, the canal impulse rotatory test cannot replace the caloric test.
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Affiliation(s)
- B Cohen
- CHI Montfienneil, av. du Gal Leclerc, Montfermeil, France
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Abstract
Leaves, roots and rhizomes, and inflorescenses of Pulmonaria obscura from two localities and of two different growth forms within one site were analyzed by GC-MS for their content in pyrrolizidine alkaloids (PAs). In roots and rhizomes PAs of the lycopsamine type typical for the Boraginaceae could be detected, e. g. intermedine, lycopsamine, and their O(7)-derivatives. The total PA concentrations in roots and rhizomes lay between 0.026 and 0.158 mg/g dry weight. In leaves and inflorescenses, on the other hand, only trace amounts of PAs (below 0.4 ng/mg dry weight) could be detected. No significant differences in total concentration of PAs could be found between the two sites.
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Affiliation(s)
- W Haberer
- Institut für Zoologie, Universität Freiburg, Freiburg, Germany
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Cohen B, Dobler S, Sauron B, Hazan A, Peytral C, Fombeur JP. Comparison between caloric and canal impulse rotatory test. Acta Otorhinolaryngol Belg 2002; 56:309-12. [PMID: 12244894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
It has been suggested that the rotatory test using videonystagmoscopy can also be applied for identification of vestibular canal paresis. In this study, we test this hypothesis by comparing the results of a canal impulse rotatory test with those of the caloric test using the method described by Freyss. Our study indicates that only in 38% of all tested patients, the same results between the two tests have been obtained. Furthermore, when the group with abnormal findings is observed separately, in 24% patients only these two test methods lead to the same results. Consequently, the canal impulse rotatory test cannot replace the caloric test.
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Affiliation(s)
- B Cohen
- CHI Montfermeil, av. du Gal Leclerc, Montfermeil, France
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Abstract
We investigated in eight species of the flea beetles genus Longitarsus (Coleoptera, Chrysomelidae) whether the beetles take up iridoid glycosides from their host plants of the Lamiaceae, Plantaginaceae, and Scrophulariaceae. Five of the beetle species, L. australis, L. lewisii, L. melanocephalus, L. nigrofasciatus, and L. tabidus, could be shown to sequester iridoid glycosides in concentrations between 0.40 and 1.55% of their dry weight. Eight different iridoid glycosides, acetylharpagide, ajugol, aucubin, catalpol, 8-epi-loganic acid, gardoside, geniposidic acid, and harpagide could be identified in the host plants, yet only aucubin and catalpol are sequestered by the beetles. No iridoid glycosides could be detected in the beetles if neither aucubin nor catalpol were present in the host plant, as in L. minusculus on Stachys recta (acetylharpagide only) and in L. salviae on Salvia pratensis (no iridoid glycosides). In one beetle species, L. luridus, we could not detect any iridoid glycosides although its field host, Plantago lanceolata, had considerable amounts of aucubin and catalpol plus two further iridoids. The five sequestering Longitarsus species differ in their capacity to store the compounds and in their affinity for catalpol relative to aucubin.
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Affiliation(s)
- G Willinger
- Institut für Zoologie, Universität Freiburg, Hauptstr. 1, 79104, Freiburg, Germany
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