Matthias Hoetzinger

• PostDoc Position at University of Innsbruck

Microbiome-directed dietary interventions such as microbiota-directed fibers (MDFs) have a proven track record in eliciting responses in beneficial gut microbes and are increasingly being promoted as an effective strategy to improve animal production systems. Here we used initial metataxonomic data on fish gut microbiomes as well as a wealth of a p...

To ensure sustainable aquaculture, it is essential to understand the path ‘from feed to fish’, whereby the gut microbiome plays an important role in digestion and metabolism, ultimately influencing host health and growth. Previous work has reported the taxonomic composition of the Atlantic salmon (Salmo salar) gut microbiome; however, functional in...

Implications of geographic separation and temporal dynamics on the evolution of free-living bacterial species are widely unclear. However, the vast amount of metagenome sequencing data generated during the last decades from various habitats around the world provides an unprecedented opportunity for such investigations. Here we exploited publicly av...

Microbiome-directed dietary interventions such as microbiota-directed fibers (MDFs) have a proven track record in eliciting responses in beneficial gut microbes and are increasingly being promoted as an effective strategy to improve animal production systems. Here we used initial metataxonomic data on fish gut microbiomes as well as a wealth of a p...

The essential role of the gut microbiota for host health and nutrition is well established for many terrestrial animals, while its importance for fish and particularly Atlantic salmon is unclear. Here, we present the Salmon Microbial Genome Atlas (SMGA) originating from wild and farmed fish both in freshwater and seawater, and consisting of 211 hig...

Bacteriophages and bacteria are engaged in a constant arms race, continually evolving new molecular tools to survive one another. To protect their genomic DNA from restriction enzymes, the most common bacterial defence systems, double-stranded DNA phages have evolved complex modifications that affect all four bases. This study focuses on modificati...

Geographic separation is a principal factor for structuring populations of macroorganisms, with important consequences for evolution, by means of processes such as allopatric speciation. For free-living prokaryotes, implications of geographic separation on their evolution are more unclear. The limited phylogenetic resolution of commonly used marker...

At the genome level, microorganisms are highly adaptable both in terms of allele and gene composition. Such heritable traits emerge in response to different environmental niches and can have a profound influence on microbial community dynamics. As a consequence, any individual genome or population will contain merely a fraction of the total genetic...

Bacteriophages and bacteria are engaged in a constant arms race, continually evolving new molecular tools to survive one another. To protect their genomic DNA from restriction enzymes, the most common bacterial defence systems, double-stranded DNA phages have evolved complex modifications that affect all four bases. This study focuses on modificati...

Visible surface films, termed slicks, can extensively cover the sea surface, particularly in coastal regions. The sea-surface microlayer (SML), the upper 1-mm at the air-water interface in slicks (slick SML) harbors a distinctive bacterial community, but little is known about SML viruses. Using flow cytometry, metagenomics, and cultivation, we inve...

At the genome level, microorganisms are highly adaptable both in terms of allele and gene composition. Such heritable traits emerge in response to different environmental niches and can have a profound influence on microbial community dynamics. As a consequence of this, any individual genome or clonal population will contain merely a fraction of th...

Phages modulate bacterial metabolism during infection by regulating gene expression, which influences aquatic nutrient cycling. However, effects of shifting nutrient regimes are less understood. Here, we analysed transcriptomes of an ecologically relevant Gammaproteobacterium and its lytic phage in high (HNM) and low (LNM) nutrient medium. Despite...

Phage predation constitutes a major mortality factor for bacteria in aquatic ecosystems, and thus, directly impacts nutrient cycling and microbial community dynamics. Yet, the population dynamics of specific phages across time scales from days to months remain largely unexplored, which limits our understanding of their influence on microbial succes...

Current knowledge on environmental distribution and taxon richness of free‐living bacteria is mainly based on cultivation‐independent investigations employing 16S rRNA gene sequencing methods. Yet, 16S rRNA genes are evolutionarily rather conserved, resulting in limited taxonomic and ecological resolutions provided by this marker. The faster evolvi...

Current knowledge on environmental distribution and taxon richness of free-living bacteria is mainly based on cultivation-independent investigations employing 16S rRNA gene sequencing methods. Yet, 16S rRNA genes are evolutionarily rather conserved, resulting in limited taxonomic and ecological resolutions provided by this marker. We used a faster...

Allopatric divergence is one of the principal mechanisms for speciation of macro-organisms. Microbes by comparison are assumed to disperse more freely and to be less limited by dispersal barriers. However, thermophilic prokaryotes restricted to geothermal springs have shown clear signals of geographic isolation, but robust studies on this topic for...

Polynucleobacter asymbioticus strain QLW-P1DMWA-1T represents a group of highly successful heterotrophic ultramicrobacteria that is frequently very abundant (up to 70% of total bacterioplankton) in freshwater habitats across all seven continents. This strain was originally isolated from a shallow Alpine pond characterized by rapid changes in water...

Polynucleobacter (Burkholderiaceae, Betaproteobacteria) and Limnohabitans (Comamonadaceae, Betaproteobacteria) are abundant freshwater bacteria comprising large genetic and taxonomic diversities, with species adapted to physico-chemically distinct types of freshwater systems. The relative importance of environmental drivers, i.e., physico-chemistry...

Po.ly.nu.cle.o.bac'ter. Gr. adj. polys, many, numerous; L. masc. n. nucleus, a little nut, kernel; N.L. masc. n. bacter, a rod; N.L. masc. n. polynucleobacter, the rod (bacterium) with many nucleoids. Proteobacteria / Betaproteobacteria / Burkholderiales / Burkholderiaceae / Polynucleobacter The genus Polynucleobacter harbors bacteria with distinct...

Six Polynucleobacter (Burkholderiaceae, Betaproteobacteria) strains isolated from different freshwater lakes located across Europe were taxonomically investigated. Phylogenetic analyses based on 16S rRNA gene sequences assigns all six strains to the cryptic species complex PnecC within the genus Polynucleobacter. Analyses of partial glutamine synth...

Background In many prokaryotic genera a clustered phylogeny is observed, akin to the occurrence of species in sexually reproducing organisms. For some taxa, homologous recombination has been invoked as the underlying mechanism providing genomic cohesion among conspecific individuals. Whether this mechanism is applicable to prokaryotes in freshwater...

Importance: Assessing the ecological relevance of bacterial diversity is a key challenge for current microbial ecology. The polyphasic approach which was applied in this study, including targeted isolation of strains, genome analysis and ecophysiological tests, is crucial for the linkage of genetic and ecological knowledge. Particularly great impo...

Strain QLW-P1FAT50C-4T, isolated from a shallow acidic freshwater pond located in the Austrian Alps at an altitude of 1300 m, was characterized by investigation of phenotypic, chemotaxonomic and genomic traits. As shown previously, phylogenetic analyses based on 16S rRNA gene sequences place the strain in the cryptic species complex PnecC within th...

Siderocalins are particular lipocalins that participate in the innate immune response by interfering with bacterial siderophore-mediated iron uptake. Additionally, siderocalins are involved in several physiological and pathological processes such as inflammation, iron delivery, tissue differentiation, and cancer progression. Here we show that sider...

Siderocalin Q83 is a small soluble protein that has the ability to bind two different ligands (enterobactin and arachidonic acid) simultaneously in two distinct binding sites. Here we report that Q83 exhibits an intriguing dynamic behavior. In its free form, the protein undergoes significant micro-to-millisecond dynamics. When binding arachidonic a...

Siderocalins are atypical lipocalins able to capture siderophores with high affinity. They contribute to the innate immune response by interfering with bacterial siderophore-mediated iron uptake but are also involved in numerous physiological processes such as inflammation, iron delivery, tissue differentiation, and cancer progression. The Q83 lipo...