Diseases of red deer introduced to Patagonia and implications for native ungulates

The red deer (Cervus elaphus) invasion in Patagonia has been continuing for nearly a century, with occurrence in all habitats between 34-55°S. Their distribution, movement patterns and locally high densities raise concerns over their potential epidemiological role in maintaining disease reservoirs or transmitting diseases like foot-and-mouth disease or tuberculosis, with potential severe health and economical impact at the interface of humans, livestock or native wildlife.  Among adult females collected by rifle and radiocollared deer that died naturally, no ectoparasites were found (n=73). Fasciola hepatica was encountered in three surveys at prevalences ranging from  9 to 50% (n=108). Taenia ovis krabbei was identified, and Cysticerus tenuicollis was found at a prevalence of 8% (n=12). Ostertagia sp., Bunostomum sp., and Dictyocaulus sp. had a prevalence of 75%, 25% and 13% (n=9), respectively. Several gastrointestinal parasites reported at low prevalence in endangered Patagonian huemul (Hippocamelus bisulcus), are common in livestock and considered commensals in domestic ruminants. Sympatry of huemul with livestock is commonplace, whereas with red deer it occurs in 100 years in Argentina, both red deer and livestock play epidemiological roles for shared diseases. Research, conservation and management efforts should be directed towards livestock herd health programs or restriction of free livestock movements, particularly if diseases are shown to have impact on recruitment of endangered natives. Livestock are routinely researched and inspected at slaughter and thus provide a proxy for diseases afflicting co-existing ungulates.Testing for antibodies to foot-and-mouth disease viral antigen was negative (n=41). A tentative diagnosis of mycobacterial infection  was based on typical visceral  lesions. Antler damage occurred on 73% of shed antlers, with 36% having major breaks of tines and main beams, possibly indicating mineral imbalances. One male had both antlers, including pedicles with portions of frontal, parietal and occipital bones broken off the skull, causing his death. The prevalence of 0.9% of campylognathia (n=776) indicates that the disease unlikely is inheritable, because the founding stock of 20 animals would have had a prevalence of at least 5%. Among deer, handedness of scoliosis related significantly to the hemisphere where specimens originated (p <0.001, n=131). Coriolis forces are known to affect early stages of development such as the innervation pattern of the mammalian vestibular system, or the plane of bilateral symmetry. It is therefore conceivable that the networks processing these environmental cues, or the mechanisms responsible for compensation, are malfunctioning and thus result in a preponderance of facial scoliosis in accordance to the earth´s rotation.Fil: Fluck, Werner Thomas. Universidad de Basilea; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Smith Flueck, Jm. Universidad Atlantida Argentina; Argentin

Klimabedingte Biodiversitätsveränderungen in limnischen Systemen – eine Diskursfeldanalyse

The Knowledge Flow Paper on hand is linking a problem-oriented discourse field analysis to the broader subject of climatically caused changes of freshwater systems and their biodiversity. This synthesis is a first step towards a better understanding of the impacts of climate change on biodiversity in freshwater systems, which are too little investigated and understood compared to terrestrial ecosystems. Following a brief introduction of the method, the main arenas are being presented and in a second step strands of discourse will be identified. The aim of the analysis is to identify priority issues, key actors and their positions, to distinguish undisputed knowledge of contested knowledge as well as to point out possible future research questions – as formulated by the actors or deduced from analysing contested knowledge. Finally, we will draw conclusions within this field of climatically caused changes of freshwater ecosystems to provide an orientation for a further involvement of the research centre in cross-cutting issues and aims of intervention into the discourse

Genetic and evolutionary analysis of diversification and reproductive isolation in yeast

In this thesis, I examine the mechanisms of evolution at different levels, from evolutionary conflict between selfish genes within a single individual (Chapter 1), through social evolution acting within a species (Chapter 2), to genetic divergence and incompatibility between closely related species (Chapters 3 & 4). The thesis therefore investigates how tiny genetic differences occurring in individuals accumulate and produce discontinuous groups

Daphnia metacommunity dynamics : the roles of inbreeding, parasitism, competition, and dispersal

The habitats of many species are not continuous but fragmented, either naturally or increasingly due to human land use. Communities of species inhabiting fragmented habitat patches are connected by dispersal and form a metacommunity, a spatial overlay of the metapopulations of the individual species. The factors enabling coexistence of different species in communities may shed light on the core questions of ecology, which is on the search for explanations for the abundance of species and their interactions with the biotic and abiotic environment. With this thesis, I aimed at contributing to a better understanding of the interplay of potential determinants of species coexistence at the local and regional scales in metacommunities. I studied a metacommunity of the three generalist filter-feeding planktonic water flea species Daphnia longispina, D. magna, and D. pulex, which form local communities in ephemeral freshwater rock pools although they have largely overlapping niches. To corroborate my observational and experimental findings, I combined them with a long-term demographic data set by V.I. Pajunen on the presence of the three species in over 500 rock pools since 1982. The largest and most abundant species D. magna is known to harbour a high diversity of ecto- and endoparasites, and the diversity of parasites in local D. magna populations was shown to correlate primarily with population age. I screened rock pool populations of the congeneric species D. longispina over a period of three years and inspected which epidemiological, spatial, temporal, and physicochemical factors explained most of the variance in the number of parasites. Contrary to the situation in D. magna, parasite richness in D. longispina was generally substantially lower, and surprisingly, the best predictor was the presence of D. magna, indicating that the co-occurring congeneric species might serve as a reservoir of parasites from which D. longispina is constantly inflicted. At the same time, the presence of parasites could be the decisive factor mediating coexistence between the two Daphnia species. Daphnia magna does not only carry the largest parasite burden but is as well the most dynamic species in terms of extinction and colonisation events in the metacommunity. To understand the factors of invasion success of D. magna, I conducted a fully factorial outdoor mesocosm experiment where D. magna clones that were outbred, unparasitised or did not face competition by resident D. longispina had a higher invasion success. The three factors inbreeding, parasitism, and interspecific competition are suggested to affect colonisation dynamics in the metacommunity and to determine whether the sequential arrival of Daphnia species in rock pool habitats can result in local coexistence. Not only invasion success proved to be diminished by competition, the competitive hierarchy of species is generally considered an important determinant for coexistence. Therefore I studied the interspecific competitive abilities of the three Daphnia rock pool species in two further outdoor mesocosm experiments. The interspecific competitive abilities of forty D. magna clones competing against D. longispina and D. pulex correlated positively and were higher when the clones originated from genetically more diverse populations, which is suggested to be a consequence of reduced inbreeding depression. The competitive abilities of the three Daphnia species competing in pairs against one another followed almost invariably a transitive competition hierarchy, i.e. the largest species D. magna was competitively superior to the intermediately sized D. pulex which in turn was competitively superior to the smallest species D. longispina. Such transitive competitive hierarchies are supportive of the size efficiency hypothesis which states that larger species dominate smaller species in the absence of predation because of their higher feeding efficiency. Conversely, I propose that the rare but naturally possibly more prevalent intransitive competitive relationships are a key factor for the maintenance of clonal and species diversity in Daphnia rock pool communities. Since rock pools are highly stochastic habitats, a requirement of local coexistence is the sufficient provisioning of immigrants by means of dispersal. Daphnia depend on passive dispersal by resting stages, so-called ephippia. To obtain a direct estimate of the absolute dispersal effort, I trapped ephippia over three years in areas inhabited predominantly by D. longispina and D. magna. The majority of caught ephippia stemmed from D. magna, which supports earlier conclusions that D. magna ephippia are more often exposed to the supposedly dominant dispersal agent wind since the species prefers smaller, more desiccation-prone rock pools. In contrast, I speculate that D. longispina may be dispersed predominantly by means of insects which may be charged by this species' buoyant ephippia

Cleaning symbiosis and the disease triangle

Pauline Narvaez found that the dedicated cleaner fish, Labroides dimidiatus, is susceptible to a diversity of parasites and can potentially transmit them to their fish clients. Her work presents a paradigm shift in the prevailing theory that cleaning symbiosis has predominantly positive impacts on coral reef fish communities

An analysis of competitive traits in pest ant species

The successful spread of invasive species can often be explained by specific behavioral, morphological, chemical and genetic traits. Studies suggest that those traits are also present in native species that expand strikingly fast and turn into an issue for the environment. Mass occurrences of the native pest ant species Formica fuscocinerea have recently become a concern for leisure areas in Southern Germany. This thesis investigates whether these mass occurrences can similarly be explained by traits known from invasive species, such as a high interspecific dominance and extensive colony networks. As cooperation among large numbers of individuals requires pronounced communication abilities, this thesis also investigates whether pheromone communication contributes to the superiority of invasive ants. Therefore, competitive strength and pheromone communication of the invasive garden ant Lasius neglectus is compared with those of the two closely related native sister species Lasius niger and Lasius platythorax. Identifying the pheromones used for communication can facilitate more specific control of pest ant species. Targeted controlmethods use baits or traps that are equipped with species-specific pheromone attractants. Ants naturally use pheromone attractants produced in pheromone glands for foraging. This thesis compares hindgut, poison gland and Dufour’s gland pheromones of L. neglectus against those of L. niger and L. platythorax to identify species-specific attractants for the invasive garden ant. The results show that the native pest ant species F. fuscocinerea is able to dominate other ant species by pronounced interspecific aggression. In contrast, F. fuscocinerea does not show intraspecific aggression among individuals from distant populations indicating weak or nonexistent colony boundaries. Thus, the striking mass occurrences of F. fuscocinerea can be attributed to traits known from invasive ant species. The trail communication of the invasive garden ant L. neglectus seems to be adapted to the exploitation of stable and productive food sources. Lasius neglectus shows a higher precision in following hindgut trails than the native Lasius species. The pheromone blends of the studied glands are notably different. Of 60 identified substances are 9 specific to the invasive L. neglectus, 26 to L. niger and 4 to L. platythorax. The chemical attractant 2,6-dimethyl-3-ethyl-5-hepten-1-ol can unambiguously be assigned to the hindgut of the invasive garden ant L. neglectus. Thus, this substance is a promising candidate for a species-specific attractant in the control of the invasive garden ant L. neglectus. High interspecific aggression and supercolonial structures are important traits of invasive ant species and this dissertation suggests that they likewise enable the native pest ant F. fuscocinerea to become dominant. A considerably more sophisticated pheromone communication does not necessarily belong to traits of invasive ants, particularly L. neglectus. However, the findings are provisional and require further investigation. Yet, the analyses of the communication pheromones provide a basis for the species-specific control of L. neglectus.Die erfolgreiche Ausbreitung invasiver Arten kann häufig mit bestimmten Verhaltensweisen, morphologischen, chemischen und genetischen Eigenschaften erklärt werden. Untersuchungen lassen vermuten, dass diese Eigenschaften auch bei den heimischen Arten vorkommen, die sich auffallend schnell ausbreiten und zu einem Problem für die Umwelt werden. Massenvorkommen der heimischen Pestameisenart Formica fuscocinerea wurden jüngst zu einem großen Problem auf Freizeitflächen in Süddeutschland. Diese Arbeit untersucht, inwiefern dieseMassenvorkommen auf ähnlicheWeise durch Eigenschaften erklärt werden können, wie sie von invasiven Arten bekannt sind, wie etwa eine hohe zwischenartliche Dominanz und ausgedehnte Kolonievernetzung. Da die Kooperation einer großen Anzahl von Individuen ausgeprägte Kommunikationsfähigkeiten benötigt, untersucht diese Arbeit zudem, ob die Pheromonkommunikation zur Überlegenheit invasiver Arten beiträgt. Dafür werden die Konkurrenzstärke und die Pheromonkommunikation der invasiven Gartenameise Lasius neglectus mit denen zweier nah verwandter heimischer Schwesternarten Lasius niger und Lasius platythorax verglichen. Eine Identifikation der Pheromone, die für die Kommunikation verwendet werden, kann eine spezifischere Bekämpfung von Pestameisenarten ermöglichen. Zielgerichtete Kontrollmethoden verwenden Köder oder Fallen, diemit artspezifischen Pheromonlockstoffen ausgestattet sind. Ameisen verwenden Pheromonlockstoffe, die in Pheromondrüsen produziert werden, naturgemäß bei der Futtersuche. Diese Arbeit vergleicht Pheromone aus dem Enddarm, der Giftdrüse und der Dufourdrüse von L. neglectus mit denen von L. niger and L. platythorax um artspezifische Lockstoffe für die invasive Gartenarmeise zu identifizieren. Die Ergebnisse zeigen, dass die heimische Pestameisenart F. fuscocinerea in der Lage ist, andere Ameisen durch ausgeprägte zwischenartliche Aggression zu dominieren. ImGegensatz dazu zeigt F. fuscocinerea keine innerartliche Aggression zwischen Individuen von entfernten Populationen, was auf schwache oder nicht vorhandene Koloniegrenzen hinweist. Folglich können die auffälligen Massenauftreten von F. fuscocinerea Eigenschaften zugeschrieben werden, die von invasive Ameisenarten bekannt sind. Die Spurkommunikation der invasiven Gartenameise L. neglectus scheint an die Ausbeutung stabiler und ergiebiger Nahrungsquellen angepasst zu sein. Lasius neglectus zeigt eine höhere Präzision beim Verfolgen von Enddarmspuren als die heimischen Lasius Arten. Die Pheromonzusammensetzungen der untersuchten Drüsen sind deutlich unterschiedlich. Von 60 identifizierten Substanzen sind 9 spezifisch für die invasive L. neglectus, 26 für L. niger und 4 für L. platythorax. Der chemische Lockstoff 2,6-Dimethyl-3-ethyl-5-hepten-1-ol kann eindeutig dem Enddarmder invasive Gartenameise L. neglectus zugeordnet werden. Diese Substanz ist somit ein vielversprechender Kandidat für einen artspezifischen Lockstoff zur Bekämpfung der invasiven Gartenameise L. neglectus. Hohe zwischenartliche Aggression und superkoloniale Strukturen sind wichtigeMerkmale invasiver Ameisenarten und diese Arbeit weist darauf hin, dass sie in gleicher Weise der heimischen Pestart F. fuscocinerea ermöglichen dominant zu werden. Eine deutlich raffiniertere Pheromonkommunikation gehört allerdings nicht notwendigerweise zu den Merkmalen invasiver Ameisen, insbesondere nicht zu denen von L. neglectus. Die Erkenntnisse gelten jedoch nur vorläufig und benötigen weitere Untersuchungen. Dennoch bietet die Analyse der Kommunikationspheromone eine Grundlage für die artspezifische Kontrolle von L. neglectus

Final report for the CORE Organic Cofund funded project “MIX-ENABLE: MIXEd livestock farming for improved sustaiNABiLity and robustnEss of organic livestock”

Multi-species livestock farming consists of keeping two or more animal species – or more generally combining different animal production units – on the same farm. It was often proposed as a solution towards higher sustainability of livestock farms but in practice although the proof of evidence was limited. This is why in MIX-ENABLE, our objective was to develop the knowledge base on organic multi-species livestock farms. To do so, we combined several approaches: We synthesized potential benefits and limitations of multi-species livestock farming for farm sustainability from existing literature. We showed that multi-species livestock farming has the potential to improve the five dimensions of farm sustainability reviewed: resource-use efficiency and conservation, animal health and welfare, productivity, profitability and human welfare; as long as locally relevant farming practices are used, especially an appropriate stocking rate during grazing. We conducted a desktop analysis of specialized and multi-species organic livestock farms. We compared 3 farm samples from France over the period 2000-2016: farms specialized in one ruminant species (219 farms), farms with two ruminant species (44 farms) and farms with ruminants and monogastrics (17 farms). We showed that multi-species farms, especially those combining ruminants and monogastrics, tend to have a higher and more stable income (in the range 506-532 €/ha against 338-455 €/ha with a coefficient of variation in the range 43-49% against 59-80%) but create higher N surplus (in the range 32-77 kg N/ha against -3-3 kg N/ha). Overall it showed that the theoretical benefits of multi-species livestock farming often reported in the literature are not systematic. We surveyed 127 farms to collect data on key aspects of farm structure, crop, pasture and livestock management, raw material inflows and outflows, economics and social data (satisfaction of the farmer, workload). Data on strengths and weaknesses, opportunities and threats perceived by farmers were also collected to identify the levers and barriers to the development of organic multi-species livestock farming. After cleaning and verification, data on 102 farms were organized in a database from which we showed among other things that 6 out of 86 farms that outperform their peers (based on four indicators) despite having the same resources and constraints. They have very different sizes and enterprise combinations but all have a strong autonomy for feed and strong interactions among farm activities. They also very often practice direct sales and have set up a satisfactory work organization, both intra-farm and with local networks. Using experimental trials, we showed that: (i) when sequentially grazing young dual-purpose steers with lambs, next to the well-established effects on lambs, no benefits but also no disadvantages for steers were observed, neither in terms of parasite egg excretion nor in daily weight gains; (ii) when co-grazing beef cattle batches and sheep flocks, mixing species seem to be profitable for sheep with no effects on cattle: all the lambs could be finished at pasture before winter whereas 10% of the lambs from the solitaire sheep flock had to be finished indoor. Lambs and ewes in mixed flock also excreted less parasite eggs; and (iii) when rearing cattle and broilers on the same pasture, losses of broiler chickens due to predatory birds were reduced. Farm simulation modelling were conducted over four French farms surveyed using Orfee, a bio-economic model that optimizes a function of net income under market and policy variability. Simulations showed that the risk associated with 70% reduction of grassland yield was by far the highest. Three of the four farms had significant risk of negative income for the baseline situation. The reduction of stocking rate reduced variability of income in all cases, nonetheless it did not remove the probability to have very low income. The introduction of a pig enterprise and the replacement of beef with dairy did not much reduce the variability but increased income and consequently reduced farm vulnerability. Various communication and dissemination items have been produced including an educational toolkit stimulate students’ learning on organic multi-species livestock farming

Interferenz in Signaltransduktionswege als therapeutischer Ansatz bei Prionkrankheiten

Prionkrankheiten sind stets tödliche, neurodegenerative, infektiöse Erkrankungen, die unterteilt werden können in sporadische, genetisch-familiäre oder erworbene Formen. Sie sind auch bekannt unter dem Namen transmissible spongiforme Enzephalopathien (TSEs). Zu ihnen gehören die Creutzfeldt-Jakob Erkrankung (CJD), das Gerstmann-Sträussler-Scheinker Syndrom (GSS), Kuru, die fatale (letale) familiäre Insomnie (FFI) und die Variante der CJD (vCJD) im Menschen, Scrapie bei Schafen und Ziegen sowie die bovine spongiforme Enzephalopathie bei Rindern (BSE). Prion-Erkrankungen werden durch die Akkumulierung einer abnormal gefalteten Isoform des zellulären Prion Proteins PrPc verursacht, die PrPSc genannt wird und den Hauptbestandteil von infektiösen Prionen darstellt. Die Konversion des zellulären Prion Proteins PrPc in seine pathogene Isoform PrPSc und die Akkumulierung von aggregiertem PrPSc sind demnach wesentliche Merkmale von Prion-Erkrankungen. Auf der Suche nach Wegen für eine mögliche Therapie und/oder Prophylaxe wurde bisher eine Vielzahl von experimentellen Ansätzen durchgeführt, mit dem Ziel in die Prion-Konversion einzugreifen. In dieser Arbeit sollte der Frage nachgegangen werden, ob durch einen Eingriff in zelluläre Signaltransduktionsprozesse ein Effekt auf die Konversion von PrPc in PrPSc ausgeübt werden kann. Dafür wurde von etwa 50 verschiedenen Substanzen, die spezifische Signalwege der Zelle inhibieren, der Effekt auf die Prion-Konversion in Prion-infizierten Zellen untersucht. Der Tyrosin-Kinasen Inhibitor STI571 zeigte in diesem Screening als einzige Substanz eine sehr starke Reduktion von PrPSc. Die Konzentration, mit der eine 50 %ige Reduktion von PrPSc in Prion-infizierten Zellen erreicht werden kann (IC50), liegt bei &#8804;1 µM. Weitere Untersuchungen ergaben, dass der durch STI571 ausgelöste anti-Prion Effekt zeit- und dosisabhängig ist und keinen Effekt auf die Biogenese, die Lokalisierung oder die biochemischen Eigenschaften der zellulären Isoform PrPc hat. Experimente zum molekularen Wirkungsmechanismus zeigten, dass STI571 nicht die Neusynthese von PrPSc inhibiert, sondern vielmehr den lysosomalen Abbau von bereits in der Zelle vorhandenem PrPSc aktiviert. Hierbei wird die zelluläre Halbwertszeit von PrPSc, die unter normalen Umständen sehr hoch ist und bei mehr als 24 Stunden liegt, auf unter 9 Stunden reduziert. Die Ergebnisse lassen vermuten, dass durch STI571 nicht die allgemeine lysosomale Aktivität der Zellen erhöht wird, sondern dass es spezifisch den physiologischen Abbau von PrPSc aktiviert und dadurch die zelluläre Clearance von PrPSc erhöht. Schließlich konnte das molekulare Ziel von STI571, das spezifisch die drei Tyrosin-Kinasen c-Kit, den PDGF(platelet derived growth factor)-Rezeptor und c-Abl inhibiert, bestimmt werden. Den verschiedenen durchgeführten Untersuchungen zufolge wird die Degradierung von PrPSc durch die Inhibition der Kinase c-Abl ausgelöst. Diese Ergebnisse zeigen, dass durch Eingriffe in die zelluläre Signaltransduktion auf den Prozess der Prion-Konversion Einfluss genommen und die zelluläre Clearance von PrPSc aktiviert werden kann. Demnach stellen Signaltransduktionswege generell potentielle Ziele für Ansätze zur Prophylaxe und Therapie von Prion-Erkrankungen dar. Substanzen, die spezifisch in Signaltransduktionsprozesse der Zelle eingreifen, sind somit eine neue Klasse von Substanzen mit anti-Prion Wirkung

Comparative analysis of gene expression associations between mammalian hosts and Plasmodium

Artenübergreifende Interaktionen helfen uns, Krankheitsmechanismen zu verstehen und Targets für Therapien zu finden. Die Koexpression von Genen, gemessen an der mRNA-Häufigkeit, kann Interaktionen zwischen Wirt und Pathogen aufzeigen. Die RNA-Sequenzierung von Wirt und Pathogen wird als "duale RNA-Sequenzierung" bezeichnet. Malaria ist eine der am besten untersuchten parasitären Krankheiten, so dass eine Fülle von RNA-seq-Datensätzen öffentlich zugänglich ist. Die Autoren führen entweder duale RNA-seq durch, um den Wirt und den Parasiten gleichzeitig zu untersuchen, oder sie erhalten kontaminierende Sequenzierungs-Reads aus dem Nicht-Zielorganismus. Ich habe eine Meta-Analyse durchgeführt, bei diese beiden Arten von RNA-seq-Studien verwendet wurden, um über korrelierte Genexpression auf Wirt-Parasit-Interaktionen zu schließen. Ich habe Studien mit Homo sapiens, Mus musculus und Macaca mulatta als Wirte und ihre Plasmodium-Parasiten einbezogen. Ich benutzte orthologe Einzelkopien von Genen, um ein Repertoire von Interaktionen bei Malaria und in diesen Modellsystemen zu erstellen. Ich verknüpfte die Daten von 63 Plasmodium-Phasen-spezifischen Studien und reduzierte die Zahl der Interaktionen von potenziell 56 Millionen auf eine kleinere, relevantere Menge. Die Zentralität in den Netzwerken der Blutphasen konnte die Essentialität der Plasmodium-Gene erklären. Das aus den verketteten Daten sagte die Genessenzialität besser vor als die einzelnen Studien - ein Vorteil der Meta-Analyse. Neutrophile und Monozyten Immunmarkergene waren überrepräsentiert, was auf eine Fülle von phagozytären und respiratorischen Reaktionen hindeutet. Die Analyse der Leberphase ergab Wirts- und Parasitenprozesse in frühen und späten Entwicklungsphasen. Ich fand bekannte Wirt-Parasit-Interaktionen, die für beide Phasen gleich sind, sowie bisher unbekannte Interaktionen. Dieses Prinzip lässt sich auch auf andere Krankheiten anwenden, um Mechanismen und therapeutische Ziele zu verstehen.Cross-species interactions help us understand disease mechanisms and find targets for therapy. Gene co-expression, measured by mRNA abundance, can identify host-pathogen interactions. The RNA-sequencing of host and pathogen is termed “dual RNA-sequencing”. Malaria is one of the most studied eukayotic parasitic diseases, making an abundance of RNA-seq data sets publicly available. Authors either perform dual RNA-seq to study the host and parasite simultaneously or acquire contaminant sequencing reads from the non-target organism. I performed a meta-analysis using these two kinds of RNA-seq studies to infer host-parasite interactions using correlated gene expression. I included studies of Homo sapiens, Mus musculus and Macaca mulatta as hosts and their corresponding Plasmodium parasites. I used single-copy orthologous genes to generate a repertoire of interactions in human malaria and in these model systems. I found 63 malaria RNA-seq studies. I concatenated sequencing runs from Plasmodium stage-specific studies and reduced the number of interactions from a potential 56 million to a smaller, more relevant set. Centrality in the blood stage networks was able to explain Plasmodium gene essentiality. The network from the concatenated data predicted gene essentiality better than the individual studies, indicating a benefit of the meta-analysis. Immune marker genes for neutrophils and monocytes were over-represented, suggesting an abundance of phagocytic and respiratory burst-related responses. The liver stage analysis revealed linked host and parasite processes at early stages until late developmental stages. I found linked host and parasite processes that are common to the two stages, e.g. parasite cell gliding and invasion and host response to hypoxia and immune response. I showed that existing data can be explored for new information. This principle can be applied to other diseases to understand mechanisms and therapeutic targets

Symbiotic bacteria in hepatopancreas (midgut glands) of isopods (Crustacea: Isopoda) : phylogeny, evolution, and distribution

Terrestrial isopods harbor uncultured bacterial symbionts in their midgut glands (hepatopancreas) that may have facilitated the evolutionary shift to utilizing terrestrial leaf litter during the course of colonizing land. In a first molecular-biological approach, we screened isopods from marine, semi-terrestrial, terrestrial, and freshwater habitats for hepatopancreatic bacterial symbionts by means of 16S rRNA gene cloning and sequencing, denaturing gel gradient electrophoresis (DGGE), fluorescence-labeled specific oligonucleotide probe in situ hybridization (FISH), and electron microscopy. There are no hepatopancreatic bacteria in the marine isopod Idotea balthica, while high numbers of nearly uniform morphotypes of bacteria were detected in semi-terrestrial (Ligia oceanica), terrestrial (Porcellio scaber, Oniscus asellus, Philoscia muscorum, Armadilidium vulgare, Trachelipus rathkii, and Alloniscs perconvesus), and freshwater (Asellus aquaticus) isopods. Phylogenetic analyses demonstrated that the symbiotic bacteria in this three types of isopod species are not closely related but belong to bacterial taxa as different as Pseudomonas (g-Proteobacteria, similarity >98%) in L. oceanica, Rickettsiales (a-Proteobacteria, similarity 95%), Burkholderia (b-Proteobacteria, similarity >98%), Aeromonas (g-Proteobacteria, similarity >99%) and Rickettsiella (g-Proteobacteria, similarity >96%) in A. aquaticus, respectively. These findings suggest that hepatopancreatic symbionts either have been acquired several times independently or have been exchanged during isopod evolution. Rickettsia-like and Mycoplasma-like symbionts of terrestrial isopod represent prevalent symbionts in several geographically distinct isopod populations. These results suggest either a common ancestor of terrestrial isopod that already harboured these bacteria symbionts or horizontal inter-specific transmission of the symbionts. Based on FISH and diagnostic PCR techniques, our data suggest that the Mycoplasma-like hepatopancreatic symbionts of P. scaber are environmentally transmitted to the new progeny exposing to the external environment. Except for the g-Proteobacteria and b-Proteobacteria found in L. oceanica and A. aquaticus, respectively, close relatives of isopod symbionts are not known to produce any enzyme that might facilitate the digestion of leaf litter, suggesting that the proposed contribution of bacterial symbionts to digestive processes of isopod hosts is unlikely