WorldCat Identities

Albert-Ludwigs-Universität Freiburg Lehrstuhl Mikrobiologie

Works: 6 works in 6 publications in 2 languages and 14 library holdings
Roles: Contributor, Other
Publication Timeline
Most widely held works by Albert-Ludwigs-Universität Freiburg
DNA-interacting characteristics of the archaeal rudiviral protein SIRV2_Gp1 by Eveline Peeters( )

1 edition published in 2017 in English and held by 3 WorldCat member libraries worldwide

Abstract: Whereas the infection cycles of many bacterial and eukaryotic viruses have been characterized in detail, those of archaeal viruses remain largely unexplored. Recently, studies on a few model archaeal viruses such as SIRV2 (Sulfolobus islandicus rod-shaped virus) have revealed an unusual lysis mechanism that involves the formation of pyramidal egress structures on the host cell surface. To expand understanding of the infection cycle of SIRV2, we aimed to functionally characterize gp1, which is a SIRV2 gene with unknown function. The SIRV2_Gp1 protein is highly expressed during early stages of infection and it is the only protein that is encoded twice on the viral genome. It harbours a helix-turn-helix motif and was therefore hypothesized to bind DNA. The DNA-binding behavior of SIRV2_Gp1 was characterized with electrophoretic mobility shift assays and atomic force microscopy. We provide evidence that the protein interacts with DNA and that it forms large aggregates, thereby causing extreme condensation of the DNA. Furthermore, the N-terminal domain of the protein mediates toxicity to the viral host Sulfolobus. Our findings may lead to biotechnological applications, such as the development of a toxic peptide for the containment of pathogenic bacteria, and add to our understanding of the Rudiviral infection cycle
More than the "killer trait": infection with the bacterial endosymbiont Caedibacter taeniospiralis causes transcriptomic modulation in Paramecium host by Katrin Grosser( )

1 edition published in 2018 in English and held by 3 WorldCat member libraries worldwide

Abstract: Endosymbiosis is a widespread phenomenon and hosts of bacterial endosymbionts can be found all-over the eukaryotic tree of life. Likely, this evolutionary success is connected to the altered phenotype arising from a symbiotic association. The potential variety of symbiont's contributions to new characteristics or abilities of host organisms are largely unstudied. Addressing this aspect, we focused on an obligate bacterial endosymbiont that confers an intraspecific killer phenotype to its host. The symbiosis between Paramecium tetraurelia and Caedibacter taeniospiralis, living in the host's cytoplasm, enables the infected paramecia to release Caedibacter symbionts, which can simultaneously produce a peculiar protein structure and a toxin. The ingestion of bacteria that harbor both components leads to the death of symbiont-free congeners. Thus, the symbiosis provides Caedibacter-infected cells a competitive advantage, the "killer trait." We characterized the adaptive gene expression patterns in symbiont-harboring Paramecium as a second symbiosis-derived aspect next to the killer phenotype. Comparative transcriptomics of infected P. tetraurelia and genetically identical symbiont-free cells confirmed altered gene expression in the symbiont-bearing line. Our results show up-regulation of specific metabolic and heat shock genes whereas down-regulated genes were involved in signaling pathways and cell cycle regulation. Functional analyses to validate the transcriptomics results demonstrated that the symbiont increases host density hence providing a fitness advantage. Comparative transcriptomics shows gene expression modulation of a ciliate caused by its bacterial endosymbiont thus revealing new adaptive advantages of the symbiosis. Caedibacter taeniospiralis apparently increases its host fitness via manipulation of metabolic pathways and cell cycle control
Viruses of microbes by Laurent Debarbieux( )

1 edition published in 2017 in English and held by 3 WorldCat member libraries worldwide

Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation by Hana Šmejkalová( )

1 edition published in 2010 in English and held by 2 WorldCat member libraries worldwide

Diversity and environmental distribution of the cosmopolitan endosymbiont "Candidatus Megaira" by Olivia Lanzoni( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Abstract: Members of the order Rickettsiales are often found in association with ciliated protists. An interesting case is the bacterial endosymbiont "Candidatus Megaira", which is phylogenetically closely related to the pathogen Rickettsia. "Candidatus Megaira" was first described as an intracellular bacterium in several ciliate species. Since then it has been found in association with diverse evolutionary distantly-related hosts, among them other unicellular eukaryotes, and also algae, and metazoa, such as cnidarians. We provide the characterization of several new strains of the type species "Candidatus Megaira polyxenophila", and the multidisciplinary description of a novel species, "Candidatus Megaira venefica", presenting peculiar features, which highlight the diversity and variability of these widespread bacterial endosymbionts. Screening of the 16S rRNA gene short amplicon database and phylogenetic analysis of 16S rRNA gene hypervariable regions revealed the presence of further hidden lineages, and provided hints on the possibility that these bacteria may be horizontally transmitted among aquatic protists and metazoa. The phylogenetic reconstruction supports the existence of at least five different separate species-level clades of "Candidatus Megaira", and we designed a set of specific probes allowing easy recognition of the four major clades of the genus
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Alternative Names
Albert-Ludwigs-Universität Freiburg Institut für Biologie 2 Lehrstuhl Mikrobiologie

Albert-Ludwigs-Universität Freiburg Institut für Biologie 2 Microbiology

Albert-Ludwigs-Universität Freiburg Institut für Biologie 2 Mikrobiologie