Publications by authors named "Dirk Wagner"

The Eger Rift subsurface is characterized by frequent seismic activity and consistently high CO concentrations, making it a unique deep biosphere ecosystem and a suitable site to study the interactions between volcanism, tectonics, and microbiological activity. Pulses of geogenic H during earthquakes may provide substrates for methanogenic and chemolithoautotrophic processes, but very little is currently known about the role of subsurface microorganisms and their cellular processes in this type of environment. To assess the impact of geologic activity on microbial life, we analyzed the geological, geochemical, and microbiological composition of rock and sediment samples from a 238 m deep drill core, running across six lithostratigraphic zones.

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Lake Sentani is a tropical lake in Indonesia, consisting of four interconnected sub-basins of different water depths. While previous work has highlighted the impact of catchment composition on biogeochemical processes in Lake Sentani, little is currently known about the microbiological characteristics across this unique ecosystem. With recent population growth in this historically rural area, the anthropogenic impact on Lake Sentani and hence its microbial life is also increasing.

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Ferruginous conditions prevailed through Earth's early oceans history, yet our understanding of biogeochemical cycles in anoxic iron-rich, sulfate-poor sediments remains elusive in terms of redox processes and organic matter remineralization. Using comprehensive geochemistry, cell counts, and metagenomic data, we investigated the taxonomic and functional distribution of the microbial subsurface biosphere in Lake Towuti, a stratified ferruginous analogue. Below the zone in which pore water becomes depleted in electron acceptors, cell densities exponentially decreased while microbial assemblages shifted from iron- and sulfate-reducing bacterial populations to fermentative anaerobes and methanogens, mostly selecting Bathyarchaeia below the sulfate reduction zone.

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Background: Although plastic pollution is increasing worldwide, very little is known about the microbial processes that take place once plastic debris is incorporated into the soil matrix. In this study, we conducted the first metatranscriptome analysis of polyethylene (PE)-associated biofilm communities in highly polluted landfill soil and compared their gene expression to that of a forest soil community within a 53-day period.

Results: Our findings indicate that the microbial population present in soil contaminated with plastic debris is predisposed to both inhabit and degrade plastic surfaces.

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Background: Spontaneous intracerebral abscess formation is a rare condition presenting with a disabling sequela. The origin of infection can either be primary or secondary to an infection at another location. The site of primary infection - due to the proximity, often the oral cavity, the sinuses, and the orbit - determines the causative pathogens.

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The Atacama Desert in Chile is one of the driest and most inhospitable places on Earth. To analyze the diversity and distribution of microbial communities in such an environment, one of the most important and challenging steps is DNA extraction. Using commercial environmental DNA extraction protocols, a mixture of living, dormant, and dead cells of microorganisms is extracted, but separation of the different DNA pools is almost impossible.

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Background: Identifying patients at risk of nontuberculous mycobacterial pulmonary disease (NTM-PD) is challenging. Delays in NTM-PD identification and management are associated with declining lung function and increased morbidity and mortality.

Study Design And Methods: European NTM-PD experts (n=12) participated in a three-round modified Delphi process to score symptoms and comorbidities potentially associated with NTM-PD as reasons to test for nontuberculous mycobacteria.

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Introduction: The incidence and prevalence of nontuberculous mycobacterial pulmonary disease (NTM-PD) are increasing globally. Approximately 80% of NTM-PD cases in Japan and five countries within Europe (Eur5; France, Germany, Italy, Spain, and the UK) are caused by Mycobacterium avium complex (MAC). This study describes the clinical decision-making process associated with the management of patients with NTM-PD in Japan and the Eur5.

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Article Synopsis
  • Soil bacterial communities are important for soil stability and interact with local climates and soil depths, affecting their diversity across different environments.
  • An innovative DNA separation method was used to analyze microbial communities in various climates along the Chilean Coastal Cordillera, revealing that intracellular DNA (iDNA) diversity increased with soil moisture, peaking in slightly deeper layers in arid conditions.
  • The study found that soil pH and moisture are critical in shaping bacterial communities, with different bacterial taxa associated with distinct environmental conditions; eDNA communities were more environmentally correlated than iDNA communities.
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After contracting COVID-19, a substantial number of individuals develop a Post-COVID-Condition, marked by neurologic symptoms such as cognitive deficits, olfactory dysfunction, and fatigue. Despite this, biomarkers and pathophysiological understandings of this condition remain limited. Employing magnetic resonance imaging, we conduct a comparative analysis of cerebral microstructure among patients with Post-COVID-Condition, healthy controls, and individuals that contracted COVID-19 without long-term symptoms.

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The Gram-positive, rod-shaped endophytic bacterium sp. strain ATA003 was isolated from the endemic cactus seeds collected in the Coastal Atacama Desert, Chile. Here, we present a circular genome with a size of 4,084,881 bp and a GC content of 73.

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Desert environments constitute one of the largest and yet most fragile ecosystems on Earth. Under the absence of regular precipitation, microorganisms are the main ecological component mediating nutrient fluxes by using soil components, like minerals and salts, and atmospheric gases as a source for energy and water. While most of the previous studies on microbial ecology of desert environments have focused on surface environments, little is known about microbial life in deeper sediment layers.

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Several studies have investigated changes in microbial community composition in thawing permafrost landscapes, but microbial assemblages in the transient ecosystems of the Arctic coastline remain poorly understood. Thermokarst lakes, abrupt permafrost thaw features, are widespread along the pan-Arctic coast and transform into thermokarst lagoons upon coastal erosion and sea-level rise. This study looks at the effect of marine water inundation (imposing a sulfate-rich, saline environment on top of former thermokarst lake sediments) on microbial community composition and the processes potentially driving microbial community assembly.

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The microbiota is attributed to be important for initial soil formation under extreme climate conditions, but experimental evidence for its relevance is scarce. To fill this gap, we investigated the impact of microbial communities and their interrelationship with biocrust and plants compared to abiotic controls on soil formation in initial arid and semiarid soils. Additionally, we assessed the response of bacterial communities to climate change.

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Purpose: This study aims to describe clinical, virological and radiological characteristics as well as treatment strategies and outcomes of immunocompromised patients with persistent SARS-CoV-2 replication.

Methods: We performed a retrospective cohort study of immunocompromised patients at the University Medical Center Freiburg between 01/2022 and 05/2023. Patients with substantial immunosuppression and persistent SARS-CoV-2 detection (Ct-value < 30 after 14 days) were included.

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Nontuberculous mycobacterial (NTM) isolation and pulmonary disease (NTM-PD) have continued to increase in most regions of the world, driven mainly by Mycobacterium avium. Single-center studies also support increasing trends as well as a persistent burden of undiagnosed NTM among persons suspected of having tuberculosis (TB), in countries with moderate-to-high TB prevalence. Cumulative exposure to water and soil presents an increased risk to susceptible hosts, and trace metals in water supply are recently recognized risk factors.

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Article Synopsis
  • The study focused on the prevalence and incidence of non-tuberculous mycobacteria (NTM) pulmonary diseases in Germany from 2016 to 2020, using data from 22 NTM laboratories.
  • Researchers found that the incidence and prevalence of NTM remained stable over the five-year period, despite variations in species and drug susceptibility testing (DST) rates.
  • An increase in the proportion of NTM with DST suggests improved awareness and reporting, but current levels still fall short of clinical needs.
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Microorganisms are known to be natural agents of biocorrosion and mineral transformation, thereby potentially affecting the safety of deep geological repositories used for high-level nuclear waste storage. To better understand how resident microbial communities of the deep terrestrial biosphere may act on mineralogical and geochemical characteristics of insulating clays, we analyzed their structure and potential metabolic functions, as well as site-specific mineralogy and element composition from the dedicated Mont Terri underground research laboratory, Switzerland. We found that the Opalinus Clay formation is mainly colonized by Alphaproteobacteria, Firmicutes, and Bacteroidota, which are known for corrosive biofilm formation.

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The simultaneous extraction of intracellular DNA (iDNA) and extracellular DNA (eDNA) can help to separate the living in situ community (represented by iDNA) from background DNA that originated both from past communities and from allochthonous sources. As iDNA and eDNA extraction protocols require separating cells from the sample matrix, their DNA yields are generally lower than direct methods that lyse the cells within the sample matrix. We, therefore, tested different buffers with and without adding a detergent mix (DM) in the extraction protocol to improve the recovery of iDNA from surface and subsurface samples that covered a variety of terrestrial environments.

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Introduction: Long-term stability of underground CO storage is partially affected by microbial activity but our knowledge of these effects is limited, mainly due to a lack of sites. A consistently high flux of mantle-derived CO makes the Eger Rift in the Czech Republic a natural analogue to underground CO storage. The Eger Rift is a seismically active region and H is produced abiotically during earthquakes, providing energy to indigenous microbial communities.

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Methanogenic archaea are a diverse, polyphyletic group of strictly anaerobic prokaryotes capable of producing methane as their primary metabolic product. It has been over three decades since minimal standards for their taxonomic description have been proposed. In light of advancements in technology and amendments in systematic microbiology, revision of the older criteria for taxonomic description is essential.

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Background: Despite vaccination coronavirus disease 2019 (COVID-19)-associated mortality caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains high in kidney transplant recipients. Nirmatrelvir is a protease inhibitor with activity against SARS-CoV-2. Nirmatrelvir reduces the risk for mortality and hospitalization, which is approved for treating adults at risk for severe disease.

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