• CUBE - Computational Systems Biology

  • DOME - Microbial Ecology

  • TER - Terrestrial Ecosystem Research

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Latest publications

Viruses comprise an extensive pool of mobile genetic elements in eukaryote cell cultures and human clinical samples.

Viruses shape a diversity of ecosystems by modulating their microbial, eukaryotic, or plant host metabolism. The complexity of virus-host interaction networks is progressively fathomed by novel metagenomic approaches. By using a novel metagenomic method, we explored the virome in mammalian cell cultures and clinical samples to identify an extensive pool of mobile genetic elements in all of these ecosystems. Despite aseptic treatment, cell cultures harbored extensive and diverse phage populations with a high abundance of as yet unknown and uncharacterized viruses (viral dark matter). Unknown phages also predominated in the oropharynx and urine of healthy individuals and patients infected with cytomegalovirus despite demonstration of active cytomegalovirus replication. The novelty of viral sequences correlated primarily with the individual evaluated, whereas relative abundance of encoded protein functions was associated with the ecologic niches probed. Together, these observations demonstrate the extensive presence of viral dark matter in human and artificial ecosystems.-Thannesberger, J., Hellinger, H.-J., Klymiuk, I., Kastner, M.-T., Rieder, F. J. J., Schneider, M., Fister, S., Lion, T., Kosulin, K., Laengle, J., Bergmann, M., Rattei, T., Steininger, C. Viruses comprise an extensive pool of mobile genetic elements in eukaryote cell cultures and human clinical samples.

Thannesberger J, Hellinger HJ, Klymiuk I, Kastner MT, Rieder FJ, Schneider M, Fister S, Lion T, Kosulin K, Laengle J, Bergmann M, Rattei T, Steininger C
2017 - FASEB J., in press

Lifestyle and Horizontal Gene Transfer-Mediated Evolution of Mucispirillum schaedleri, a Core Member of the Murine Gut Microbiota.

Mucispirillum schaedleri is an abundant inhabitant of the intestinal mucus layer of rodents and other animals and has been suggested to be a pathobiont, a commensal that plays a role in disease. In order to gain insights into its lifestyle, we analyzed the genome and transcriptome of M. schaedleri ASF 457 and performed physiological experiments to test traits predicted by its genome. Although described as a mucus inhabitant, M. schaedleri has limited capacity for degrading host-derived mucosal glycans and other complex polysaccharides. Additionally, M. schaedleri reduces nitrate and expresses systems for scavenging oxygen and reactive oxygen species in vivo, which may account for its localization close to the mucosal tissue and expansion during inflammation. Also of note, M. schaedleri harbors a type VI secretion system and putative effector proteins and can modify gene expression in mucosal tissue, suggesting intimate interactions with its host and a possible role in inflammation. The M. schaedleri genome has been shaped by extensive horizontal gene transfer, primarily from intestinal Epsilon- and Deltaproteobacteria, indicating that horizontal gene transfer has played a key role in defining its niche in the gut ecosystem. IMPORTANCE Shifts in gut microbiota composition have been associated with intestinal inflammation, but it remains unclear whether inflammation-associated bacteria are commensal or detrimental to their host. Here, we studied the lifestyle of the gut bacterium Mucispirillum schaedleri, which is associated with inflammation in widely used mouse models. We found that M. schaedleri has specialized systems to handle oxidative stress during inflammation. Additionally, it expresses secretion systems and effector proteins and can modify the mucosal gene expression of its host. This suggests that M. schaedleri undergoes intimate interactions with its host and may play a role in inflammation. The insights presented here aid our understanding of how commensal gut bacteria may be involved in altering susceptibility to disease.

Loy A, Pfann C, Steinberger M, Hanson B, Herp S, Brugiroux S, Gomes Neto JC, Boekschoten MV, Schwab C, Urich T, Ramer-Tait AE, Rattei T, Stecher B, Berry D
2017 - mSystems, 1: in press

A 12-week intervention with nonivamide, a TRPV1 agonist, prevents a dietary-induced body fat gain and increases peripheral serotonin in moderately overweight subjects

A bolus administration of 0.15 mg nonivamide has previously been demonstrated to reduce energy intake in moderately overweight men. This 12-week intervention investigated whether a daily consumption of nonivamide in a protein-based product formulation promotes a reduction in body weight in healthy overweight subjects, and affects outcome measures associated with mechanisms regulating food intake, e.g. plasma concentrations of an-/orexigenic hormones, energy substrates as well as changes in fecal microbiota .
Nineteen overweight subjects were randomly assigned to either a control (C) or a nonivamide group (NV). Changes in the body composition and plasma concentrations of satiating hormones were determined at fasting and 15, 30, 60, 90 and 120 min after a glucose load. Participants were instructed to consume 0.15 mg nonivamide per day in 450 mL of a milk shake additionally to their habitual diet. After treatment, a group difference in body fat mass change (- 0.61 ± 0.36 % in NV and + 1.36 ± 0.38 % in C), and an increase in postprandial plasma serotonin were demonstrated. Plasma metabolome and fecal microbiome read outs were not affected.
A daily intake of 0.15 mg nonivamide helps to support to maintain a healthy body composition. Nonivamide, a less-pungent capsaicin analog, was studied for its potential as an anti-obesity agent in a 12-week human intervention study. The body composition was determined at the beginning and in the end of intervention. Moreover, plasma concentrations of satiating hormones were measured Participants were instructed to drink the product formulation three times daily. After treatment, a group difference in body fat mass change, and an increase in postprandial plasma serotonin concentrations were determined in the nonivamide group. Thus, we suppose that a daily intake of nonivamide might help to maintain a healthy body composition. This article is protected by copyright. All rights reserved.

Hochkogler CM, Lieder B, Rust P, Berry D, Meier SM, Pignitter M, Riva A, Leitinger A, Bruk A, Wagner S, Hans J, Widder S, Ley JP, Krammer GE, Somoza V
2017 - Mol Nutr Food Res, in press

Lecture series

Microbial function in relation to plant productivity and root exudation in contrasting tundra communities

Konstantin GAVAZOV
Climate Impacts Research Centre (CIRC), Umeå University, Abisko, Sweden
20.03.2017
14:00 h
Seminar Room 'Konferenzraum Ökologie' UZA 1, Althanstr. 14, 1090 Wien