4.0 Abteilungsleitung und andere
Filtern
Dokumenttyp
- Zeitschriftenartikel (53)
- Vortrag (45)
- Posterpräsentation (17)
- Buchkapitel (4)
- Beitrag zu einem Tagungsband (3)
- Dissertation (2)
- Forschungsdatensatz (2)
- Beitrag zu einem Sammelband (1)
Schlagworte
- Fungus (11)
- Black fungi (10)
- Genetics (9)
- Knufia petricola (9)
- Fungi (7)
- Melanin (7)
- Biofilm (6)
- Evolution (6)
- Termite (6)
- Bio-weathering (5)
- DHN melanin (5)
- Immunity (5)
- Olivine (5)
- Pathogen (5)
- Light (4)
- Microcolonial fungi (4)
- Virus (4)
- Bioinformatics (3)
- Black fungus (3)
- Emerging (3)
- Extracellular polymeric substances (3)
- Extremotolerance (3)
- Pigments (3)
- Rock-inhabiting fungus (3)
- Social (3)
- Stress tolerance (3)
- Umweltsimulation (3)
- Virulence (3)
- Weathering (3)
- Aerosol (2)
- Bacteria (2)
- Bee (2)
- Biodeterioration (2)
- Biofilms (2)
- Biogenic weathering (2)
- Bioreceptivity (2)
- Botrytis cinerea (2)
- Cannibalism (2)
- Cascade impactor (2)
- Cockroach (2)
- Concrete (2)
- Disease (2)
- Entomopathogen (2)
- Forsterite (2)
- Fungal biofilms (2)
- Genomics (2)
- Gut microbiota (2)
- Knufia (2)
- Magnesium (2)
- Marble (2)
- Microbiota (2)
- Nosema ceranae (2)
- Osmia bicornis (2)
- Particles (2)
- Pigment (2)
- Plant pathogen (2)
- Schadstoffaustrag (2)
- Social immunity (2)
- Solar panel (2)
- Stress (2)
- Subaerial biofilm (2)
- Subaerial biofilms (2)
- Symbiosis (2)
- TXRF (2)
- Virology (2)
- Wild bees (2)
- fungus (2)
- genetics (2)
- melanin (2)
- (Semi)arid to humid-temperate natural ecosys (1)
- 13CO2 pulse labeling (1)
- 16S rRNA gene (1)
- 3D printing (1)
- A key interface (1)
- Adaptation (1)
- Adaption (1)
- Advanced groups of termites (1)
- Ag-LDI-MS (1)
- Agricultural mycology (1)
- Air quality monitoring (1)
- Ambient aerosol (1)
- Amplicon sequencing (1)
- Analytical Chemistry (1)
- Animal immune system (1)
- Anobium punctatum (1)
- Antibacterial coatings (1)
- Antimicrobial (1)
- Antimicrobial materials (1)
- Antimicrobial surfaces (1)
- Antimicrobial testing (1)
- Aquatic fungi (1)
- Arbuscular mycorrhiza (1)
- Ascomycetes (1)
- Ascosphaera apis (1)
- Astrobiology (1)
- Atomic and Molecular Physics and Optics (1)
- Bacterial infection (1)
- Bawit (1)
- Bee diseases (1)
- Bee health (1)
- Bees (1)
- Behavioural mechanisms (1)
- Bestandserhaltung (1)
- Bewitterung (1)
- Bio-receptive (1)
- Biodegradation (1)
- Biofilm formation (1)
- Biofouling (1)
- Bioinformatics virology viruses software (1)
- Biologically induced mineral weathering (1)
- Biosphere-technosphere interaction (1)
- Biosynthesis (1)
- Biotic environment (1)
- Black microcolonial fungi (1)
- Blattodea (1)
- Botrytis (1)
- Built environment (1)
- CEC-L-103 (1)
- CRISPR/Cas9 (1)
- Carotenoids (1)
- Chemical ecology (1)
- Chilean Coastal Cordillera (1)
- Climate gradient (1)
- Cloning vectors (1)
- Close proximity to colonies (1)
- Community composition (1)
- Community-level interactions (1)
- Confocal microscopy (1)
- Constantinomyces (1)
- Contraction (1)
- Control (1)
- Controllable gene expression (1)
- Copper-based wood preservatives (1)
- Coptic manuscripts (1)
- Crispr-Cas9 (1)
- Crispr/Cas9 (1)
- Cryptoendolithic black fungus (1)
- Cuticular hydrocarbons (1)
- Cyanobacteria (1)
- DNA barcode (1)
- DNA polymerase (1)
- De novo assembly (1)
- Desiccation (1)
- Developing building materials (1)
- Development (1)
- Differential expression (1)
- Differential gene expression analysis (1)
- Diversität (1)
- Dothideomycetes (1)
- Draft Genome (1)
- Drywood termite (1)
- DsRNA (1)
- E$volution (1)
- E. coli (1)
- EPS (1)
- Ecology (1)
- Edible insects (1)
- Element mass concentration (1)
- Element mass concetration (1)
- Emission (1)
- Entomopathogenic Fungus (1)
- Environmental simulation (1)
- Epidemal layer (1)
- Eurotiomycetes (1)
- Expansion (1)
- External (1)
- Extracellular enzymes (1)
- Extrazelluläre Polysaccharide (1)
- Extreme environments (1)
- Extremophiles (1)
- Extremophilic fungi (1)
- FAT class concept (1)
- Façade (1)
- Feeding behaviour (1)
- Flammschutzmittel (1)
- Fluorescence (1)
- Fluorescent microscopy (1)
- Fluorescent proteins (1)
- Foward genetics (1)
- Fractal structure (1)
- Fractional factorial (1)
- Fungal stress mechanisms and responses (1)
- Fungiculture (1)
- GC-FID (1)
- GC-MS (1)
- GDL (1)
- GNBP-2 (1)
- Genetic engineering (1)
- Genetic tools (1)
- Genetik (1)
- Genome (1)
- Genome editing (1)
- Genome sequence (1)
- Geobiology (1)
- Glass paints (1)
- Gray mold fungus (1)
- Green facades (1)
- Gut symbionts (1)
- Herbaspirillum seropedicae (1)
- Heterologous expression (1)
- Honey bee (1)
- Honeybee (1)
- Host and symbiont ecology (1)
- Host immunity (1)
- Hygienic behavior (1)
- Hypermutation (1)
- ICP-MS (1)
- ISO 22196 (1)
- ITS region (1)
- Illness-induced anorexia (1)
- Immune gene prediction (1)
- ImmunoDB (1)
- In-vivo mutagenesis (1)
- Indoor mycobiome (1)
- Industrial mycology (1)
- Infecting a number of insects, (1)
- Ink analysis (1)
- Insect evolution (1)
- Instrumentation (1)
- Internal pores (1)
- Isoptera (1)
- Isotopes (1)
- Knock-out mutant (1)
- Korynetes caeruleus (1)
- Kulturgut (1)
- LA-ICP-MS (1)
- LIBS (1)
- Laccase (1)
- Light regulation (1)
- Light sensing (1)
- Light-induced stress (1)
- Lignocellulose (1)
- Low cost aerosol PM sensor (1)
- Low-molecular-weight organic substances (1)
- MIC (1)
- Major transition (1)
- Marek's Disease Virus (1)
- Marek's virus (1)
- Material surface colonisation (1)
- Mathematical modelling (1)
- Mechanisms of pathogenesis (1)
- Medical mycology (1)
- Melanin Adhesion (1)
- Melanins (1)
- Metabolomics (1)
- Metadata (1)
- Metarhizium (1)
- Metarhizium robertsii DSM 1490 (1)
- Microbe (1)
- Microbial (1)
- Microbial abundance (1)
- Microbial communities (1)
- Microbiology (1)
- Microfluidics (1)
- Mikrobiell (1)
- Mineral (1)
- Mineral weathering (1)
- Mixed ink (1)
- Model organism (1)
- Molecular (1)
- Molecular clock (1)
- Molecular identification (1)
- Multi-scale study (1)
- Multicellularity (1)
- Multilocus phylogeny (1)
- Mutagenesis (1)
- N and K analog tracer (1)
- Natural abundance of 15N (1)
- Natural ecosystems (1)
- Near-infrared refectography (1)
- New exocrine organ (1)
- Nitrogen (1)
- Nitrogen fixation (1)
- Nitrogen uptake (1)
- Nostoc (1)
- Nostoc punctiforme (1)
- Nutrient acquisition (1)
- Nutrient cycles (1)
- Nutrient uplift and recyclin (1)
- Open data (1)
- Organic phosphorus breakdown (1)
- PM (1)
- PV modules (1)
- Papyrus (1)
- Partikeln (1)
- Pathogen spillover (1)
- Pathogen transmission (1)
- Pathogen virulence (1)
- Peptide-derived components (1)
- Phosphorus K-edge-XANES spectroscopy (1)
- Photocatalytic surfaces (1)
- Photoperception (1)
- Photoreceptors (1)
- Phototrophs (1)
- Phyllosphere (1)
- Pilz (1)
- Pilze (1)
- Plant economic spectrum (1)
- Pollutants (1)
- Polymerase mutant (1)
- Polypropylen (1)
- Polystyrol (1)
- Probiotic-based vaccines (1)
- Probiotics (1)
- Proofreading deficient (1)
- Proteome (1)
- Proteomics (1)
- Quality assurance (1)
- Quasispecies (1)
- RNA extraction (1)
- RNA interference (1)
- RNA-Seq (1)
- RNAi (1)
- Raman Spectroscopy (1)
- Real-time qPCR (1)
- Reductive iron assimilation (1)
- Reference material (1)
- Reference organisms (1)
- Rhizosphere (1)
- Rhizosphere effect (1)
- Rhizosphere processes (1)
- Rice (1)
- Rock biofilm (1)
- Rock leaching (1)
- Rock-inhabiting black fungi (1)
- Rock-inhabiting fungi (1)
- Root economics space (1)
- Rostral gland (1)
- SEM micrography (1)
- Schimmel (1)
- Secondary metabolism (1)
- Secondary metabolites (1)
- Sequence annotation (1)
- Short crack propagation (1)
- Siderophore (1)
- Signal transduction (1)
- Smartphone (1)
- Social insect (1)
- Sociality (1)
- Software (1)
- Soil incubation study (1)
- Soil-feeding habit (1)
- Solar panels (1)
- Solar parks (1)
- Soldier (1)
- Solitary bees (1)
- Stained glass windows (1)
- Stoichiometric homeostasis (1)
- Stone cultural heritage (1)
- Stress conditions (1)
- Subsocial (1)
- Subsoil nutrient tracing (1)
- Surface interactions (1)
- Survival rates (1)
- Systematics (1)
- Taxonomy (1)
- Temperate rain forest (1)
- Tems (1)
- Termites (1)
- Test strip (1)
- Teststreifen (1)
- Tolerance (1)
- Transcriptomics (1)
- Transposon (1)
- Tripartite interactions (1)
- UV radiation (1)
- UV tolerance (1)
- VOC (1)
- Velocimetry (1)
- Viruses (1)
- Weld fatigue (1)
- Weld toe geometry (1)
- X-ray fuorescence (1)
- X-ray tomographic (1)
- XRF (1)
- Xestobium rufovillosum (1)
- Yeast (1)
- black fungi (1)
- black fungus (1)
- carotenoids (1)
- genomics (1)
- individual-based modelling (1)
- light (1)
- mRNA-seq (1)
- pigmentation (1)
- plant pathogen (1)
- qPCR (1)
- signaling (1)
- virulence (1)
Organisationseinheit der BAM
- 4 Material und Umwelt (127)
- 4.0 Abteilungsleitung und andere (127)
- 4.1 Biologische Materialschädigung und Referenzorganismen (20)
- 4.2 Material-Mikrobiom Wechselwirkungen (8)
- 1 Analytische Chemie; Referenzmaterialien (7)
- 6 Materialchemie (6)
- 1.7 Organische Spuren- und Lebensmittelanalytik (5)
- 6.1 Oberflächen- und Dünnschichtanalyse (5)
- 1.1 Anorganische Spurenanalytik (4)
- 1.4 Prozessanalytik (4)
Paper des Monats
- ja (2)
The development of a test to evaluate the degradation of semi-volatile fuels as diesel by microorganisms is presented. This method is based on the principles described in the CEC-L-103 Standard procedure that is exclusively meant for testing the biodegradability of non-volatile lubricants. Therefore, significant modifications involve aseptic conditions for testing specific microorganisms and conducting the test in closed vessels avoiding evaporation losses, while fuel quantification using gas chromatography-flame ionization detection (GC-FID) is retained. It is suggested that the modified procedure should enable routine application for semi-volatile hydrocarbon-based fuels. GC-FID provides additionally valuable information on the alteration of fuel component patterns during biodegradation. The procedure was successfully tested using two bacteria (Pseudomonas aeruginosa and Sphingomonas sp.) and two yeasts (Moesziomyces sp. and Candida sp.) isolated from real diesel contamination cases. All tested microorganisms caused a significant degradation of diesel fuel achieving hydrocarbon degradation percentages ranging from 23% to 35%. Specific aspects on the test modification and prospects for further modification regarding targeted investigations in the field of fuel contamination by microorganisms are briefly discussed.
Gegenstand des Projekts ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polycarbonat, Polytetrafluorethylen, Polystyrol und Polypropylen zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden, die es gestatten, Schnellprüfverfahren zu etablieren, die die Simulation der realen Beanspruchungen im Zeitraffermodell anwendbar machen. Somit sollen standardisierbare Schnellbeanspruchungs-verfahren erarbeitet werden, die als Prüfeinrichtungen etabliert werden und von externen Auftraggebern zur Prüfung der Umweltbeständigkeit und -verträglichkeit von neuen Materialien genutzt werden können. Die Umweltwirkungen (chemisch-physikalisch und mikrobiologisch) sollen so definiert eingesetzt werden, dass eine reproduzierbare Prüfung möglich wird. Aus diesen Verfahren und Methoden sollen Normen abgeleitet werden, die eine standardisierte Materialprüfung ermöglichen.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umwelt-beständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Mikroskopische Pilze, die sich schnell auf verfügbaren Oberflächen ausbreiten können und die wir (wenn sie sich ansammeln), auch mit bloßem Auge erkennen können, werden Schimmelpilze genannt. Da diese Organismen verschiedene organische Kohlenstoffverbindungen als Nahrung benutzen, werden sie sich bei wachstumfördernden Feuchtigkeitsbedingungen in Bibliothekbeständen schnell ausbreiten können. Im Vortrag werden Haupteigenschaften aller Pilze, sowie auch aktuelle Methoden der Identifizierung dieser Organismen erörtert.
Benutzung geeigneter Lebendkulturen als Referenzorganismen geben der Materialprüfung und -forschung eine Möglichkeit des reproduzierbaren Experimentierens mit verschiedenen Materialien und Simulation von Bedingungen im Gebrauch. Vorteile unserer Testverfahren sind: (i) Zeitraffung und Kontrollierbarkeit der Umweltparameter; (ii) Benutzung einer naturnahen Vergesellschaftung; iii) gezielte Variationen der Prüfbedingungen im Labor.
Ziel dieser Untersuchungen ist einerseits biogene Schäden an neuen Materialien zu verfolgen und zu modellieren, und damit eine bessere Planungsgrundlage für die Materialentwicklung anzubieten. Andererseits werden mit den Referenzorganismen mikrobiologisch moderne und zeitraffende Techniken angeboten, die neue Behandlungsmethoden oder Pflegeverfahren für die Bestandserhaltung erwarten lassen.
The rotation of the Earth causes a day/night cycle that is characterized by changing light and temperature conditions. Fungi actively sense the environmental light conditions to induce protective mechanisms against the light-associated stresses and to regulate development. Since fungi adapted to habitats with different light regimes, the complexities of their ‘visual’ systems and photoresponses may vary significantly. Fungi that are associated with plants experience a special light regime because the host seeks optimum light conditions for photosynthesis – and the fungus must cope with them. Moreover, fungi living under the canopy are confronted with an altered spectrum enriched for green and far-red light. Plants sense light to coordinate growth and morphogenesis: a low red:far-red ratio indicates the presence of competitors (shading by other plants) and triggers the shade avoidance response which is accompanied by increased susceptibility to nectrophic pathogens.
Botrytis cinerea, the causal agent of gray mold diseases on many plant species in moderate climate zones (high humidity, temperatures around 20°C, seasons), exhibits striking photoresponses accompanied by a broad action spectrum and a high number of photoreceptors. Light is the most important factor controlling morphogenesis: it induces conidiation for disease spreading (summer cycle) and represses sclerotial development for survival and/or sexual recombination (winter cycle). In the past years, we identified several cellular components involved in photoperception and regulation of photomorphogenesis and virulence indicating that the same signaling pathways are of relevance for both processes, propagation and infection. Notably, we recognized the role of the phytochromes (red/far-red light sensors) for coordinated responses to light and elevated temperatures (photo-/thermomorphogenesis) – similar to the function of Arabidopsis PhyB. BcPHY2-like thermosensors are likely restricted to the Leotiomycetes, which include several plant pathogens of the moderate climate zones.
Sunlight, the major source of energy, drives life but in excess it provokes UV-induced DNA damage, accumulation of reactive oxygen species, desiccation, osmotic stresses and so on. Biological strategies to survive excess light include protection, avoidance and active utilisation. Phototrophic organisms including cyanobacteria, green algae and plants use all three strategies. Fungi occupying phototrophic niches may profit from the surplus photosynthetic products which also obliges them to cope with the same light-induced stresses. One way of handling these stresses would be to use similar signalling pathways to sense the presence and to interact with their phototrophic partners. Obviously, the levels of adaptation and responses to light will depend on the environment as well as fungal genotype and phylogenetic position. Black fungi – a polyphyletic group – accumulate the dark pigment DHN melanin in their cell walls and often occupy light-flooded habitats from phyllosphere to rock surfaces. Here we compare two sequenced melanised fungi of different lifestyles in their response to light.
The Leotiomycete Botrytis cinerea is an aggressive pathogen that primarily infects the above-ground parts of plants. It possesses large numbers of photoreceptors that respond to a broad spectrum of light. As a consequence, light controls morphogenesis in which it induces conidiation for disease spreading and represses sclerotial development for survival and/or sexual recombination. Cellular components involved in photo-perception and regulation of morphogenesis, stress responses and virulence have been identified and appear to regulate propagation, survival and infection. These include phytochromes, a group of photoreceptors which are particularly enriched in the Leotiomycetes and that mediate coordinated responses to light and elevated temperatures. Assuming that photo-regulation may be equally important for fungi that live in mutualistic relationships with phototrophs either by forming composite organisms or biofilms, we investigate the role of light in the rock-inhabiting Eurotiomycete Knufia petricola. Like other black yeasts, K. petricola grows slowly, does not form specialised reproductive structures and constitutively produces DHN melanin as well as carotenoids. Combining K. petricola with the cyanobacterium Nostoc punctiforme, we developed a model system for studying biofilm formation and bio-weathering. A genetic toolbox to manipulate this model system is being developed. K. petricola strain A95 possesses ten putative photoreceptors, more than found in filamentous Eurotiomycetes suggesting that light plays an important role for abiotic and biotic interactions in extremo-tolerant and symbiosis-capable fungi.
19th and 20th centuries glass paint layers consist of a colour body and a colourless lead silicate flux, in which borax or boric acid was added as further component to improve the paint ability and to reduce the firing temperature for multiple layers of paint. Model glasses were used in laboratory tests to investigate the stability of glass paints with additions of boron oxide. To determine boron in paint layers, a LIBS-system with pulsed NdYAG-laser was used.
In the modern world there is an increased understanding that design and performance monitoring of materials have to be tested in connection to chemical, physical and (micro)biological challenges. A systematic study on how biofilms interact with materials and what could be done to engineer biofilms and/or materials in order to maximize the resistance of the material (surface) or the resistance the biofilm-modified material (bulk) is in strong need. In the Department “Materials and the Environment” of the BAM new experimental platform is being developed. With the help of different type of device for high throughput and microbiologically-controlled environment simulation we establish a new approach to clarify the mechanisms of biofilm/material interactions. Despite the focus on fundamental research, the main results of this project proposal will be transferable into material technology and construction chemistry and will influence the development of standardization in this topic. As the interactions of biofilms and materials have implications for most constructions as well as climate change, the results of the research generates additional value.
Interface between the atmosphere and mineral substrates is the oldest terrestrial habitat. Morphologically simple microbial biofilms were the first settlers on these inhospitable surfaces at times when the Earth was inhabited only by microorganisms and the solid substrates represented only by natural rock surfaces i.e. lithosphere. Miniature, self-sufficient microbial ecosystems continue to develop on subaerial (i.e. air-exposed) solid surfaces at all altitudes and latitudes where direct contact with the atmosphere and solar radiation occurs – on rocks, mountains, buildings, monuments, solar panels. All these sub-aerial biofilms develop under fluctuating and hostile conditions – and thus frequently harbour stress-tolerant black fungi inherently able to cope with the stresses of bright sunlight and constantly changing atmospheric conditions. Black fungi – a polyphyletic group of Ascomycetes– accumulate the dark pigment DHN melanin, diverse carotenoids and mycosporines in their cells and thus successfully colonise sunlight-flooded habitats from phyllosphere to rock surfaces. Various chemical and physical extremes and fluctuating environments belong to the challenges effectively mastered by black fungi. In our laboratory we isolate novel black fungi from man-made habitats like building materials and solar panels. Using Knufia petricola A95 as a model we conduct experiments to clarify interactions of black fungi with inorganic substrates. We use available mutants to determine the functional consequences of changes in the outer cell wall envelopes – from excreted EPS to layers of protective pigments. A genetic toolbox to manipulate this Chaetothyriales representative is in further development. Our long-term goal is to understand the fundamental mechanisms how black fungi are able (i) to adhere to dry atmosphere-exposed surfaces, (ii) to survive multiple stresses and (iii) to change the underlying substrates including rocks.
The story of how black fungi survive harsh conditions on sun-exposed desert rocks and material surfaces is fascinating. In the presentation examples of how knowledge of these organisms can be of practical value (e.g., in biodeterioration studies, such as on stone markers in cemeteries) would be given. Among other stories, the example of how roof tiles amended with a titanium oxide layers as a biocide actually selected for the black fungi will be told. A hypothesis about how these organisms would likely be found on solar panels and some early BAM work in that area will be presented. This then brings the connection to a study ripe for investigation in North Carolina. The talk presents the development of a study aiming at deciphering the influence of microbial biofilm formation on the energy conversion efficiency of solar photovoltaic panels or modules at two facilities (one facility under the impact of high intensity of animal agriculture and high deposition of ammonia from atmosphere and the other with low animal agriculture and lower atmospheric ammonia deposition) in North Carolina. The main hypothesis of the study is that microbial biofilm formation on solar photovoltaic panels will lead to significant decreases in energy conversion efficiency of solar photovoltaic modules and biofilm formation will also be accelerated by high ammonia concentration in the ambient atmosphere and high nitrogen deposition.
This file contains all the data used for the figures shown in the Dissertation of Ruben Gerrits with the title "An experimental study of fungal olivine weathering".
In this study, the weathering-affecting, rock-inhabiting fungus, Knufia petricola A95 and the Fe-bearing olivine (Fe0.2Mg1.8SiO4) were selected to investigate fungi-induced effects on mineral dissolution. The availability of a melanin-deficient mutant (ΔKppks) of K. petricola A95, that produced more extracellular polymeric substances (EPS) than the wild type (WT), enabled comparative studies of the role of melanin and EPS in weathering processes.
RNA virus populations are composed of highly diverse individuals that form a cloud of related sequences commonly referred to as a ‘quasispecies’1–3. This diversity arises as a consequence of low-fidelity genome replication4,5. By contrast, DNA Virus populations contain more uniform individuals with similar fitness6.
Genome diversity is often correlated with increased Fitness in RNA viruses, while DNA viruses are thought to require more faithful genome replication. During DNA replication, erroneously incorporated bases are removed by a 3′-5′ exonuclease, a highly conserved enzymatic function of replicative DNA but not RNA polymerases. This proofreading process enhances replication fidelity and ensures the genome integrity of DNA organisms, including large DNA viruses7. Here, we show that a herpesvirus can tolerate impaired exonucleolytic proofreading, resulting in DNA virus populations, which, as in RNA viruses8, are composed of highly diverse genotypes of variable individual fitness. This indicates that herpesvirus mutant diversity may compensate for individual Fitness loss. Notably, in vivo infection with diverse virus populations results in a marked increase in virulence compared to genetically homogenous parental virus. While we cannot exclude that the increase in virulence is caused by selection of and/or interactions between individual genotypes, our findings are consistent with quasispecies dynamics. Our results contrast with traditional views of DNA virus replication and evolution, and indicate that a substantial increase in population diversity can lead to higher virulence.
Mechanisms of olivine dissolution by rock-inhabiting fungi explored using magnesium stable isotopes
(2019)
To unravel the dissolution mechanisms of olivine by a rock-inhabiting fungus we determined the stable isotope ratios of Mg on solutions released in a laboratory experiment. We found that in the presence of the fungus Knufia petricola the olivine dissolution rates were about seven-fold higher (1.04×10−15 mol cm−2 s−1) than those in the abiotic experiments (1.43×10−16 mol cm−2 s−1) conducted under the same experimental condition (pH 6, 25 °C, 94 days). Measured element concentrations and Mg isotope ratios in the supernatant solutions in both the biotic and the abiotic experiment followed a dissolution trend in the initial phase of the experiment, characterized by non-stoichiometric release of Mg and Si and preferential release of 24Mg over 26Mg. In a later phase, the data indicates stoichiometric release of Mg and Si, as well as isotopically congruent Mg release. We Attribute the initial non-stoichiometric phase to the rapid replacement of Mg2+ in the olivine with H+ along with simultaneous polymerization of Si tetrahedra, resulting in high dissolution rates, and the stoichiometric phase to be influenced by the accumulation of a Si-rich amorphous layer that slowed olivine dissolution. We attribute the accelerated dissolution of olivine during the biotic experiment to physical attachment of K. petricola to the Si-richamorphous layer of olivine which potentially results in ist direct exposure to protons released by the fungal cells. These additional protons can diffuse through the Si-rich amorphous layer into the crystalline olivine. Our results also indicate the ability of K. petricola to dissolve Fe precipitates in the Si-rich amorphous layer either by protonation, or by Fe(III) chelation with siderophores. Such dissolution of Fe precipitates increases the porosity of the Si-rich amorphous layer and hence enhances olivine dissolution. The acceleration of mineral dissolution in the presence of a rock-dissolving fungus further suggests that its presence in surficial CO2 sequestration plants may aid to accelerate CO2 binding.
Free-living and (ecto)-mycorrhizal fungi enhance rock weathering. In their roles as mineral weathering agents and mutualistic partners of phototrophs, fungi supply primary producers like plants and phototrophic microorganisms with mineral-derived nutrients. The exact mechanisms behind fungus-induced mineral weathering processes are however not well understood. Progress can be achieved here by reproducible experimental simulations of the natural processes, using well-characterised model organisms and minerals.
In this study, the weathering-affecting, rock-inhabiting fungus, Knufia petricola A95 and the Fe-bearing olivine (Fe0.2Mg1.8SiO4) were selected to investigate fungi-induced effects on mineral dissolution. The availability of a melanin-deficient mutant (ΔKppks) of K. petricola A95, that produced more extracellular polymeric substances (EPS) than the wild type (WT), enabled comparative studies of the role of melanin and EPS in weathering processes.
Three experimental systems, which generate long-term microbiological stability, were developed to study the impact of the WT and ΔKppks on olivine weathering: (1) batch and (2) mixed flow dissolution experiments, and (3) biofilm cultivation experiments. In addition, state-of-the-art analytical techniques were used to monitor changes in the growth medium, as well as of the mineral surface and biofilm-mineral interface.
Inductively coupled plasma optical emission spectrometry (ICP-OES) analysis of the Mg, Si and Fe concentrations in the reacted growth medium was used to quantify olivine dissolution. In abiotic controls, Mg and Si dissolved congruently, while Fe precipitated. The measured olivine dissolution rates at pH 6 were two orders of magnitude lower than previously reported, but similar at acidic pH. X-ray photoelectron spectroscopy (XPS) analyses of the olivine surface confirmed the presence of Fe (oxyhydr)oxide precipitates. Transmission electron microscopy (TEM) imaging of an abiotically reacted polished olivine section from the long-term cultivation experiment showed the presence of an amorphous layer enriched in Fe. All these observations indicate that the precipitation of Fe (oxyhydr)oxides on the olivine surface inhibits olivine dissolution.
Both tested rock-inhabiting fungal strains affect Fe precipitation as well as olivine dissolution. Evaluation of the WT and ΔKppks revealed that the WT formed less biomass but could take up higher amounts of metals (e.g. Fe) and was more efficient in its attachment to olivine. The WT and ΔKppks enhanced olivine dissolution as demonstrated by higher Mg and Si concentration in the reacted growth medium. They furthermore prevented Fe precipitation by binding Fe and retaining it in solution, thereby allowing olivine dissolution to proceed. The WT cells that were attached to the olivine surface were particularly efficient at inhibiting Fe precipitation. By binding Fe directly at the olivine surface, the WT cells removed the inhibition of olivine dissolution almost completely. TEM analysis of polished olivine sections, colonised by a fungal biofilm for seven months, supported this hypothesis. After long-term fungus-olivine interaction, the Fe-enriched, amorphous layer did not develop, and the olivine surface was stronger etched compared to the abiotic control.
To study the effect of mutualism on mineral weathering, K. petricola was grown with the cyanobacterium, Nostoc punctiforme ATCC 29133. Both partners showed an enhanced growth and formed a stratified biofilm which attached more strongly to olivine. Nevertheless, the olivine dissolution rate of the fungus-cyanobacterium consortium was moderate.
Rock weathering simulation systems developed here are promising research instruments. The experimental conditions allow for the alteration of the studied mineral surface, while the clear definition of these conditions delivers a stable growth of microorganisms. The latter makes these systems universally applicable, especially in combination with integrative multidisciplinary analytics. Processes underlying environmental and biological effects on rock weathering, metal corrosion, plastic degradation, or the deterioration of any other substrate can be studied reproducibly and over a long period of time. The chemical and biological complexity of these simulation systems mimics natural rock weathering processes. The mineral dissolution rates generated in this study are therefore relevant to natural ecosystems.
Rice is staple food of nearly half the world’s population. Rice yields must therefore increase to feed ever larger populations. By colonising rice and other plants, Herbaspirillum spp. stimulate plant growthand productivity. However the molecular factors involved are largely unknown. To further explore this interaction, the transcription profiles of Nipponbare rice roots inoculated with Herbaspirillum seropedicae were determined by RNA-seq. Mapping the 104 million reads against the Oryza sativa cv. Nipponbare genome produced 65 million unique mapped reads that represented 13,840 transcripts each with at least two-times coverage. About 7.4% (1,014) genes were differentially regulated and of these 255 changed expression levels more than two times. Several of the repressed genes encoded proteins related to plant defence (e.g. a putative probenazole inducible protein), plant disease resistance as well as enzymes involved in flavonoid and isoprenoid synthesis. Genes related to the synthesis and efflux of phytosiderophores (PS) and transport of PS-iron complexes were induced by the bacteria. These data suggest that the bacterium represses the rice defence system while concomitantly activating iron uptake. Transcripts of H. seropedicae were also detected amongst which transcripts of genes involved in nitrogen fixation, cell motility and cell wall synthesis were the most expressed.
Fungi that share light-flooded habitats with phototrophs may profit from excess photosynthetic products. But to cope with sunlight-associated stresses it is important for fungi to accurately sense and respond to changes in light. To test the hypothesis that light is an environmental cue that Ascomycota use to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships, the photoreceptor (PR) distribution in species from different ecological niches was analysed. The genomes of black fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The filamentous foliar plant pathogen Botrytis cinerea (Leotiomycetes) has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts. Rock-inhabiting Dothideo- and Eurotiomycetes including Knufia petricola possess equal numbers of PRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and photoregulation are important for fungi that avoid loss of energy and nutrients through cooperation with phototrophs.
Social insects nesting in soil environments are in constant contact with entomopathogens and have evolved disease resistance mechanisms within a colony to prevent the occurrence and spread of infectious diseases. Among these mechanisms: mutual grooming reduces the cuticular load of pathogens, and burial of cadavers and cannibalism can prevent pathogens from replicating within the group. We explored how the rate and type of collective behavioural response is determined by stepwise infection dynamics operating at the level of the individual. Specifically, we infected the eastern subterranean termite Reticulitermes flavipes with different types of infectious particle and infection route of the entomopathogenic fungus Metarhizium anisopliae and recorded behavioural responses of nestmates to individuals at different times during the progression of infections. As expected, termites groomed conidia-exposed individuals significantly more than controls. Interestingly, grooming was significantly elevated after fungal germination than before, suggesting that pathogen growth cues act as strong stimulators of allogrooming. Conidia-exposed termites were cannibalized, but only after they became visibly ill. By contrast, termites did not groom blastospore-injected individuals more than controls at any time-point following infection. Instead, we found that blastospore-injected individuals were continually cannibalized at a low-level following injection with either viable or heat-killed blastospores, with a marked increase in cannibalism after termites injected with viable blastospores became visibly ill and were close to death. Together, these findings point to the importance of host condition as a cue for social hygienic behavior, and that the host itself appears to emit essential sickness cues that act as targets for its own sacrifice. This demonstrates that termites have independently evolved to both identify and destructively respond to sickness.
The termites are a derived eusocial lineage of otherwise non-social cockroaches. Understanding the proximal and ultimate drivers of this major evolutionary transition represents an important goal in biology. One outstanding question concerns the evolution of termite immunity, which is thought to have undergone broad-sweeping adaptations in order to enhance group-level immune protection. To understand the evolutionary origins of termite immunity, we conducted qualitative and quantitative transcriptome analyses along a gradient of sociality. Firstly, we aimed to identify large-scale genetic shifts in immune traits linked to eusociality by comparing immune gene repertoires in solitary and subsocial cockroaches and across a range of eusocial termite lineages. Secondly, we compared the responses of a solitary cockroach, a subsocial wood-roach and different castes of a lower termite species to a non-specific immune challenge, in order to understand how sociality may have influenced the evolution of immune gene regulation. Firstly, we found that termites have a broadly representative repertoire of canonical immune genes as compared to gregarious cockroaches and subsocial wood-roaches. Secondly, with respect to immune challenge, the solitary cockroach and the subsocial wood-roach displayed a similarly comprehensive induced response, while the termite response was considerably dampened by comparison and strongly influenced by caste; with reproductives displaying a generally higher constitutive level of immune-gene expression compared to sterile castes. In summary we did not find termite eusociality to be associated with significant changes in immune gene diversity, but rather to be linked with significant modifications to the regulation of immunity following the origin of division of labour.
Results suggest a reduction in immune gene repertoires in termites and possible complementary expression between termite castes. With comparative genomics we will investigate the evolution of gene families related to immunity, try to understand where reductions and expansions take place and relate these changes to shifts in sociality and ecology. The role of TEs in expansions and contractions of immune gene families will be investigated. For these analyses, we propose to generate high quality, highly contiguous genomes of species from different levels of sociality, covering all major termite families. With comparative transcriptomics we will investigate the expression of immune genes in different castes. Via network analyses we will identify pathways indicated in differential immunity between castes and between species of different sociality levels. We will investigate how these pathways have been rewired along the transitions to higher levels of sociality and how, intra-specifically, they change between castes.
A broad suite of immune adaptations have evolved in social insects which hold close parallels with the immune systems of multicellular individuals. However, comparatively little is known about the evolutionary origins of immunity in social insects. We tackle this by identifying immune genes from 18 cockroach and termite species, spanning a gradient of social lifestyles. Termites have undergone contractions of major immune gene families during the early origin of the group, particularly in antimicrobial effector and receptor proteins, followed by later re-expansions in some lineages. In a comparative gene expression analysis, we find that reproductive individuals of a termite invest more in innate immune regulation than other castes. When colonies encounter immune-challenged nestmates, gene expression responses are weak in reproductives but this pattern is reversed when colony members are immune-challenged individually, with reproductives eliciting a greater response to treatment than other castes. Finally, responses to immune challenge were more comprehensive in both subsocial and solitary cockroaches compared to termites, indicating a reduced overall ability to respond to infection in termites. Our study indicates that the emergence of termite sociality was associated with the evolution of a tapered yet caste-adapted immune system.