50 research outputs found
The All-Rounder Sodalis: A New Bacteriome-Associated Endosymbiont of the Lygaeoid Bug Henestaris halophilus (Heteroptera: Henestarinae) and a Critical Examination of Its Evolution
Hemipteran insects are well-known in their ability to establish symbiotic relationships with bacteria. Among them, heteropteran insects present an array of symbiotic systems, ranging from the most common gut crypt symbiosis to the more restricted bacteriome-associated endosymbiosis, which have only been detected in members of the superfamily Lygaeoidea and the family Cimicidae so far. Genomic data of heteropteran endosymbionts are scarce and have merely been analyzed from the Wolbachia endosymbiont in bed bug and a few gut crypt-associated symbionts in pentatomoid bugs. In this study, we present the first detailed genomic analysis of a bacteriome-associated endosymbiont of a phytophagous heteropteran, present in the seed bug Henestaris halophilus (Hemiptera: Heteroptera: Lygaeoidea). Using phylogenomics and genomics approaches, we have assigned the newly characterized endosymbiont to the Sodalis genus, named as Candidatus Sodalis baculum sp. nov. strain kilmister. In addition, our findings support the reunification of the Sodalis genus, currently divided into six different genera. We have also conducted comparative analyses between 15 Sodalis species that present different genome sizes and symbiotic relationships. These analyses suggest that Ca. Sodalis baculum is a mutualistic endosymbiont capable of supplying the amino acids tyrosine, lysine, and some cofactors to its host. It has a small genome with pseudogenes but no mobile elements, which indicates middle-stage reductive evolution. Most of the genes in Ca. Sodalis baculum are likely to be evolving under purifying selection with several signals pointing to the retention of the lysine/tyrosine biosynthetic pathways compared with other Sodalis.D.S.-G. is recipient of a PostDoctoral Fellowship from The Hebrew University of Jerusalem. This publication was funded by the German Research Foundation (DFG) and the University of Bayreuth in the funding progamme Open Access Publishing.Peer reviewe
Fatal Diplostomum phoxini infection in captive Atlantic puffin Fratercula arctica chicks following ingestion of infected European minnows Phoxinus phoxinus
Conservation of endangered animal species is a major task of zoos. Husbandry and
breeding of Atlantic puffins Fratercula arctica in captivity is challenging. In 2019, the entire chick
population (n = 4 chicks) in Berne Animal Park’s Atlantic puffin colony (Bern, Switzerland) died
within 7 d. Due to supply constraints, the chicks had been fed with wild-caught European minnows
Phoxinus phoxinus. At necropsy, the main pathological finding in all deceased puffin chicks
was a multifocal, moderate to severe subacute heterophilic and granulomatous enteritis with
intralesional adult trematodes and eggs. Metacercariae surrounded by few necrotic cells and scattered
macrophages were found in the brain and spinal cord of the food fish. Additional microbiological
analyses of both the puffin chicks and fish were unremarkable. Diplostomum phoxini DNA
could be identified in formalin-fixed paraffin-embedded tissue from the small intestine of all puffin
chicks and European minnows following PCR and sequencing of the 18S ribosomal RNA gene
and the internal transcribed spacer (ITS1) region. This report illustrates the importance of intensive
health checks of food fish for animal species kept in captivity
Excitonic channels from bio-inspired templated supramolecular assembly of J-aggregate nanowires
Supramolecular assemblies with controlled morphology are of paramount importance for energy transport in organic semiconductors. Despite considerable freedom in molecular design, the preparation of dyes that form one dimensional J-aggregates is challenging. Here, we demonstrate a simple and effective route to functionalize dendronized polymers (DPs) with J-aggregates to construct tubular DP/J-aggregate nanowires. When J-aggregates are adsorbed onto DPs anchored to glass substrates, they assemble into microcrystalline domains typical for J-aggregates adsorbed on functionalized surfaces. Differently, the complexation between the dendronized polymer and J-aggregates in solution leads to dense packing of J-aggregate strands on the periphery of the DPs. Using a layer-by-layer (LBL) technique, DPs loaded with J-aggregates can also be adsorbed onto a DP monolayer. In this case, the thin film absorption spectra are narrower and indicate higher ratios of J-aggregate to monomer and dimer absorption than bare J-aggregates deposited similarly. The demonstration of J-aggregate adsorption on filamentous polymeric templates is a promising step toward artificial 1D light harvesting antennas, with potential applications in opto-electronic devices
Decomposition of Multistage Stochastic Programs with Recombining Scenraio Trees
This paper presents a decomposition approach for linear multistage stochasticprograms, that is based on the concept of recombining scenario trees. The latter, widely applied in Mathematical Finance, may prevent the node number of thescenario tree to grow exponentially with the number of time stages. It is shownhow this property may be exploited within a non-Markovian framework and under time-coupling constraints. Being close to the well-established Nested BendersDecomposition, our approach uses the special structure of recombining trees forsimultaneous cutting plane approximations. Convergence is proved and stoppingcriteria are deduced. Techniques for the generation of suitable scenario trees andsome numerical examples are presented
Bilateral Gamma Distributions and Processes in Financial Mathematics
We present a class of Lévy processes for modelling financial market fluctuations: Bilateral Gamma processes. Our starting point is to explore the properties of bilateral Gamma distributions, and then we turn to their associated Lévy processes. We treat exponential Lévy stock models with an underlying bilateral Gamma process as well as term structure models driven by bilateral Gamma processes and apply our results to a set of real financial data (DAX 1996-1998)