Relative Selectivity of Plant Cardenolides for Na+/K+-ATPases From the Monarch Butterfly and Non-resistant Insects

This work is licensed under a Creative Commons Attribution 4.0 International License.A major prediction of coevolutionary theory is that plants may target particular herbivores with secondary compounds that are selectively defensive. The highly specialized monarch butterfly (Danaus plexippus) copes well with cardiac glycosides (inhibitors of animal Na+/K+-ATPases) from its milkweed host plants, but selective inhibition of its Na+/K+-ATPase by different compounds has not been previously tested. We applied 17 cardiac glycosides to the D. plexippus-Na+/K+-ATPase and to the more susceptible Na+/K+-ATPases of two non-adapted insects (Euploea core and Schistocerca gregaria). Structural features (e.g., sugar residues) predicted in vitro inhibitory activity and comparison of insect Na+/K+-ATPases revealed that the monarch has evolved a highly resistant enzyme overall. Nonetheless, we found evidence for relative selectivity of individual cardiac glycosides reaching from 4- to 94-fold differences of inhibition between non-adapted Na+/K+-ATPase and D. plexippus-Na+/K+-ATPase. This toxin receptor specificity suggests a mechanism how plants could target herbivores selectively and thus provides a strong basis for pairwise coevolutionary interactions between plants and herbivorous insects.German Research Foundation (GP, PE 2059/1-1)US National Science Foundation (AA, DEB-1619885

Relative Selectivity of Plant Cardenolides for Na+/K+-ATPases From the Monarch Butterfly and Non-resistant Insects

This work is licensed under a Creative Commons Attribution 4.0 International License.A major prediction of coevolutionary theory is that plants may target particular herbivores with secondary compounds that are selectively defensive. The highly specialized monarch butterfly (Danaus plexippus) copes well with cardiac glycosides (inhibitors of animal Na+/K+-ATPases) from its milkweed host plants, but selective inhibition of its Na+/K+-ATPase by different compounds has not been previously tested. We applied 17 cardiac glycosides to the D. plexippus-Na+/K+-ATPase and to the more susceptible Na+/K+-ATPases of two non-adapted insects (Euploea core and Schistocerca gregaria). Structural features (e.g., sugar residues) predicted in vitro inhibitory activity and comparison of insect Na+/K+-ATPases revealed that the monarch has evolved a highly resistant enzyme overall. Nonetheless, we found evidence for relative selectivity of individual cardiac glycosides reaching from 4- to 94-fold differences of inhibition between non-adapted Na+/K+-ATPase and D. plexippus-Na+/K+-ATPase. This toxin receptor specificity suggests a mechanism how plants could target herbivores selectively and thus provides a strong basis for pairwise coevolutionary interactions between plants and herbivorous insects.German Research Foundation (GP, PE 2059/1-1)US National Science Foundation (AA, DEB-1619885

Sequestration of defenses against predators drives specialized host plant associations in preadapted milkweed bugs (Heteroptera: Lygaeinae)

AbstractHost plant specialization across herbivorous insects varies dramatically, but while the molecular mechanisms of host plant adaptations are increasingly known, we often lack a comprehensive understanding of the selective forces that favor specialization. The milkweed bugs (Heteroptera: Lygaeinae) are ancestrally associated with plants of the Apocynaceae from which they commonly sequester cardiac glycosides for defense, facilitated by resistant NaNa+/K+-ATPases and adaptations for transport, storage, and discharge of toxins. Here, we show that three Lygaeinae species independently colonized four novel nonapocynaceous hosts that convergently produce cardiac glycosides. A fourth species shifted to a new source of toxins by tolerating and sequestering alkaloids from meadow saffron (Colchicum autumnale, Colchicaceae). Across three milkweed bug species tested, feeding on seeds containing toxins did not improve growth or speed of development and even impaired growth and development in two species, but sequestration mediated protection of milkweed bugs against two natural predators: lacewing larvae and passerine birds. We conclude that physiological preadaptations and convergent phytochemistry facilitated novel specialized host associations. Since toxic seeds did not improve growth but either impaired growth or, at most, had neutral effects, selection by predators on sequestration of defenses, rather than the exploitation of additional profitable dietary resources, can lead to obligatory specialized host associations in otherwise generalist insects

Unexpected high frequency of neurofibroma in the celiac ganglion of German cattle

In a study originally designed to find potential risk factors for bovine spongiform encephalopathy (BSE) we examined tissues from 403 Holstein Frisian cattle in total. These included 20 BSE cattle and their 236 birth- and feeding cohort animals plus 32 offspring, 103 age, breed and district-matched control cattle and further twelve cattle with neurological signs. In addition to the obex, we examined the celiac ganglion, cervical cranial ganglion, trigeminal ganglion and proximal ganglion of the vagus nerve using histological techniques. Unexpectedly, we found a high number of neurofibroma, a benign peripheral nerve sheath tumor consisting of Schwann cells, fibroblasts and perineural cells. The neurofibroma were present only in the celiac ganglion and found during histologic examination. With a frequency of 9.91% in BSE cattle and their cohorts (case animals) and 9.09% in the age, breed and district matched control animals there seems to be no correlation between the occurrence of BSE and neurofibroma. Benign peripheral nerve sheath tumors have been described more often in cattle than in other domestic animals. Usually, they are incidental macroscopic findings in the thoracic ganglia during meat inspection. To our knowledge, there are no previous systematic histologic studies including bovine celiac ganglia at all. The high incidence of celiac ganglia neurofibroma may play a role in the frequently occurring abomasal displacements in Holstein Frisian cattle as the tumors might cause a gastrointestinal motility disorder. At present a genetic predisposition for these neoplasms cannot be ruled out.Grants ZN 1294 and ZN 2168, Volkswagen Stiftung financed the first years of sample collection, i.e. material from BSE and cohort animals regarding staff and material expenses Project number: 38028266, Deutsche Forschungsgemeinschaft (DFG), was granted for the original study design to identify risk factors for BSE in the cohort animals of BSE animalsSaarland University within the funding programme Open Access Publishing

Independent evolution of ancestral and novel defenses in a genus of toxic plants (Erysimum, Brassicaceae)

Phytochemical diversity is thought to result from coevolutionary cycles as specialization in herbivores imposes diversifying selection on plant chemical defenses. Plants in the speciose genus Erysimum (Brassicaceae) produce both ancestral glucosinolates and evolutionarily novel cardenolides as defenses. Here we test macroevolutionary hypotheses on co-expression, co-regulation, and diversification of these potentially redundant defenses across this genus. We sequenced and assembled the genome of E. cheiranthoides and foliar transcriptomes of 47 additional Erysimum species to construct a phylogeny from 9868 orthologous genes, revealing several geographic clades but also high levels of gene discordance. Concentrations, inducibility, and diversity of the two defenses varied independently among species, with no evidence for trade-offs. Closely related, geographically co-occurring species shared similar cardenolide traits, but not glucosinolate traits, likely as a result of specific selective pressures acting on each defense. Ancestral and novel chemical defenses in Erysimum thus appear to provide complementary rather than redundant functions.Austrian Science Fund (FWF) PZ00P3-161472National Science Foundation (NSF) 1811965 1645256Triad FoundationGerman Research Foundation (DFG) DFG-PE 2059/3-1Agencia Estatal de Investigacion CGL2017-86626-C2-2-PLOEWE Program Insect Biotechnology and BioresourcesJunta de Andalucía A-RNM505-UGR1

Regelung von Grosswindkraftanlagen fuer Standorte in Mittelgebirgslagen Abschlussbericht

The authors worked on a new measurement and control system for testing new control methods that will reduce mechanical loads on wind power plants especially in inland low mountain sites. The system was tested on a big wind power plant of the 1.5 MW range of Tacke Windtechnik GmbH. An extensive measuring campaign was projected on a prototype TW 1.5 at Vogelsberg wind park. Unfortunately, Tacke Windechnik GmbH went bankrupt, so the plant could not be finished on time. The report therefore presents only the measurement and control system and the control methods. (orig.)Schwerpunkt des Vorhabens war die Entwicklung eines Mess- und Regelungssystems zum Test neuer Regelungsverfahren, die insbesondere an Mittelgebirgsstandorten zu einer Reduktion der mechanischen Belastung von Windkraftanlagen fuehren. Ein weiteres Ziel des Projekts war die Erprobung des entwickelten Regelungssystems an einer grossen Windkraftanlage der 1.5 MW-Leistungsklasse. Das Projekt wurde deshalb in enger Zusammenarbeit mit der Tacke Windtechnik GmbH durchgefuehrt. Durch eine umfangreiche Messkampagne sollte eine Beurteilung des Regelungsverfahrens bezueglich der mechanischen Entlastung von Anlagenkomponenten erfolgen. Diese Tests waren an einem Prototypen der TW 1.5 auf dem Gelaende des Windenergieparks Vogelsberg geplant. Leider kam die Errichtung der Anlage infolge des Konkurses von Tacke Windtechnik im Projektzeitraum nicht zustande, so dass die Erprobung bislang nicht durchgefuehrt werden konnte. Der vorliegende Bericht beschraenkt sich daher auf die Beschreibung des entwickelten Mess- und Regelungssystems und der Regelungsverfahren. (orig.)SIGLEAvailable from TIB Hannover: F98B1289+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany); Hessisches Ministerium fuer Umwelt, Energie, Jugend, Familie und Gesundheit, Wiesbaden (Germany)DEGerman

Untersuchungen zur mechanischen Beanspruchung drehzahlvariabler Windkraftanlagen unter Mittelgebirgsbedingungen im Windkraftanlagen-Testfeld Vogelsberg Abschlussbericht

Theoretical and experimental investigations were carried out. The dynamic behaviour of wind power systems and the component loads were modelled, and control processes were developed on this basis in order to reduce the mechanical component loads. The control processes were then tested in a 33 kW experimental facility in the Vogelsberg mountains test field. In the first 3-year period, measurements were made on the constant-speed test facility in order to obtain reference values. The plant was then modified for variable-speed operation at two different speeds. All three measuring phases were accompanied by an extensive measuring programme. Mechanical collective loads were defined by Fraunhofer-Institut fuer Betribsfestigkeit, Darmstadt (LBF) and are presented in a supplement volumenDie Untersuchungen wurden sowohl theoretisch als auch experimentell durchgefuehrt. Das dynamische Verhalten von Windkraftanlagen und die mechanischen Beanspruchung der Komponenten wurden zunaechst durch ein mathematisches Modell nachgebildet. Auf der Grundlage dieses Modells wurden Regelungsverfahren entwickelt, die den Betrieb der Windkraftanlage mit variabler Drehzahl ermoeglichen und zu einer geringeren mechanischen Beanspruchung der Komponenten fuehren. Im experimentellen Teil des Forschungsvorhabens wurden die entwickelten Regelungsverfahren an einer 33-kW-Experimentieranlage im Testfeld Vogelsberg erprobt. In einem Zeitraum von 3 Jahren wurde als Referenz zunaechst das Verhalten der drehzahlstarren Experimentieranlage ermittelt. Nach dem Umbau der Anlage wurde anschliessend der drehzahlvariable Betrieb mit zwei unterschiedlichen Regelungsvarianten untersucht. In jeder dieser drei Betriebsphasen wurde ein umfangreiches Messprogramm durchgefuehrt. Die Bestimmung der mechanischen Lastkollektive erfolgte durch das Fraunhofer-Institut fuer Betriebsfestigkeit, Darmstadt (LBF) und ist in einem gesonderten Abschlussbericht dokumentiert. (orig.)Available from TIB Hannover: F99B780 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEHessisches Ministerium fuer Umwelt, Energie, Jugend, Familie und Gesundheit, Wiesbaden (Germany)DEGerman