ORCID Profile
0000-0001-8414-8317
Current Organisation
Ludwig-Maximilians-Universitat Munchen
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Cold Spring Harbor Laboratory
Date: 02-06-2022
DOI: 10.1101/2022.06.02.494549
Abstract: Apicomplexan parasites have an immense impact on humanity, but their basic cellular processes are often poorly understood. The sites of endocytosis, the conservation of this process with other eukaryotes, and its functions across Apicomplexa are major unanswered questions. Yet endocytosis in Plasmodium is implicated in antimalarial drug failure. Using the apicomplexan model Toxoplasma , we identified the molecular composition and behavior of unusual, fixed endocytic structures. Here, stable complexes of endocytic proteins differ markedly from the dynamic assembly/disassembly of these machineries in other eukaryotes. Moreover, conserved molecular adaptation of this structure is seen in Apicomplexa, including the kelch-domain protein K13 central to malarial drug-resistance. We determine that an essential function of endocytosis in Toxoplasma is plasma membrane homeostasis, rather than parasite nutrition, and that these specialized endocytic structures originated early in infrakingdom Alveolata, likely in response to the complex cell pellicle that defines this medically and ecologically important ancient eukaryotic lineage.
Publisher: Wiley
Date: 15-05-2017
DOI: 10.1111/NPH.14547
Abstract: Bacterial accommodation inside living plant cells is restricted to the nitrogen‐fixing root nodule symbiosis. In many legumes, bacterial uptake is mediated via tubular structures called infection threads ( IT s). To identify plant genes required for successful symbiotic infection, we screened an ethyl methanesulfonate mutagenized population of Lotus japonicus for mutants defective in IT formation and cloned the responsible gene, ERN 1 , encoding an AP2/ERF transcription factor. We performed phenotypic analysis of two independent L. japonicus mutant alleles and investigated the regulation of ERN 1 via transactivation and DNA –protein interaction assays. In ern1 mutant roots, nodule primordia formed, but most remained uninfected and bacterial entry via IT s into the root epidermis was abolished. Infected cortical nodule cells contained bacteroids, but transcellular IT s were rarely observed. A subset exhibited localized cell wall degradation and loss of cell integrity associated with bacteroid spread into neighbouring cells and the apoplast. Functional promoter studies revealed that CYCLOPS binds in a sequence‐specific manner to a motif within the ERN 1 promoter and in combination with CC a MK positively regulates ERN 1 transcription. We conclude that the activation of ERN 1 by CC a MK / CYCLOPS complex is an important step controlling IT ‐mediated bacterial progression into plant cells.
Publisher: Cold Spring Harbor Laboratory
Date: 22-07-2020
DOI: 10.1101/2020.07.22.215848
Abstract: The continental subsurface houses a major portion of life’s abundance and ersity, yet little is known about viruses infecting microbes that reside there. Here, we used a combination of metagenomics and genome-informed microscopy to show that highly abundant carbon-fixing organisms of the uncultivated genus Candidatus Altiarchaeum are frequent targets of previously unrecognized viruses in the deep subsurface. Analysis of CRISPR spacer matches displayed resistances of Ca. Altiarchaea against eight predicted viral clades, which showed genomic relatedness across continents but little similarity to previously identified viruses. Based on metagenomic information, we tagged and imaged a putatively viral genome rich in protospacers using fluorescence microscopy. Virus-targeted genomeFISH revealed a lytic lifestyle of the respective virus and challenges previous predictions that lysogeny prevails as the dominant viral lifestyle in the subsurface. CRISPR development over time and imaging of 18 s les from one subsurface ecosystem suggest a sophisticated interplay of viral ersification and adapting CRISPR-mediated resistances of Ca. Altiarchaeum. We conclude that infections of primary producers with lytic viruses followed by cell lysis potentially jump-start heterotrophic carbon cycling in these subsurface ecosystems.
No related grants have been discovered for Andreas Klingl.