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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.
Recent studies have shown that host-microbiota interactions can lead to dramatic changes in host phenotype especially behaviour. We investigate the causal drivers of microbe-associated shifts in host phenotype by examining how feeding behaviour is modulated by a bacterial infection in an omnivorous cockroach: Blatta orientalis. We conducted food-choice experiments after challenging hosts with the common entomopathogenic soil bacterium Pseudomonas entomophila to understand the impact of bacterial pathogens on host macronutrient preference. We find that immune challenge by this bacterium drives a sharp decline in carbohydrate intake and results in a relative increase in the ratio of protein to carbohydrate consumed. Additionally, infected cockroaches reduce their overall nutrient intake. We show for the first time that cockroach feeding behaviour is dynamically modulated by a pathogen. In contrast to studies on Spodoptera moths, this modulation does not impact any of the immune parameters we measured: it does not affect the abundance of immune related proteins in the hemolymph, hemolymph antimicrobial activity, or survival. This leads to the possibility that as long-lived omnivorous species B. orientalis may be better adapted to unpredictable variation in food availability and quality. An illness-induced anorexia-like response which is thought to assist hosts in limiting nutritional resources available to pathogens is therefore the most likely cause of the observed phenotype. Reduction of carbohydrate intake by sick individuals would be consistent with such an explanation.
In another cockroach species Blatella germanica we also investigate whether in addition to pathogens, host microbiota especially gut commensals are causally responsible for shifts in host behavioural phenotype and immune competence. To address this, we conduct food-choice and immunechallenge experiments in germ-free cockroaches and naïve cockroaches.
Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). Within the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling was combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution of only a few hours and with good size resolution in the PM10 range. A proof of principles of this methodological approach and the comparison to standard methods within the scope of a field campaign will be presented. Secondly, aerosol sampling and TXRF analysis seems suitable for the quantification of elements in indoor aerosols as well and may provide an important enhancement of existing methods for the analysis of organic species in aerosols (such as sampling and TD-GC/MS). As an example, the TXRF analysis of particles emitted from laser printers under controlled conditions in an environmental test chamber will be presented.
Sunlight is an important environmental factor is almost all ecosystems by being a source of energy, information, and stress. All organisms must protect themselves from the harmful effects of light such as UV radiation, ROS accumulation, heat, and desiccation. Finally, light qualities and quantities can be used for decision making, timing and as guide for directed growth when they are sensed and transduced into intracellular signals. Botrytis cinerea and other plant pathogens infecting the sun-exposed parts of the plant must cope with the high light conditions the host plant seeks. Further they experience an altered light spectrum (‘green gap’) when they colonize shaded parts of the plant; it is depleted for blue and red light that is absorbed by the plant chlorophyll and enriched for green and far-red light that is reflected or transmitted by the plant tissue. As these ambient light conditions trigger the shade avoidance response in the plant, the pathogens may trigger their own ‘shading response’ such as the upregulation of virulence determinants and inoculum production. B. cinerea maintains a highly sophisticated light signaling machinery that senses different light qualities to trigger a variety of responses, that are protection, morphogenesis, positive and negative tropisms, and entrainment. These characteristics render B. cinerea a valuable model to enlighten the role of light in parasitic fungus-plant interactions and beyond. The vegetative mycelium – the core of all infection and developmental programs – is not visibly pigmented and thus considered to be sensitive to biotic and abiotic stresses. However, the vegetative hyphae have a very limited half-life and are usually restricted to the invasive growth phase in which they are protected from light by the plant tissue. Fast colonization of host tissues and by this proper nutrient acquisition enables the rapid formation of long-lasting reproduction structures (melanized conidiophores with conidia, sclerotia) on the surfaces of rotted plant tissues. Depending on the light and temperature conditions, conidiation or sclerotial development is initiated. Taken together, B. cinerea uses light-regulated signaling networks to avoid light whenever possible; for example, by minimizing the half-life of sensitive cells that are hiding in plant tissues and by scheduling critical steps such as conidiogenesis, conidial germination and penetration of plant tissues for the night.
Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. But to cope with sunlight-associated stresses [e.g. high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses] it is important for fungi to accurately sense and respond to changes in light. The genomes of black [dihydroxynaphthalene (DHN) melanin-containing] fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The 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 Dothideomycetes 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 -regulation are important for fungi that receive nutrients through cooperation with phototrophs.
Black fungi also called black yeasts, rock-inhabiting fungi or microcolonial fungi are a group of Ascomycetes [Eurotiomycetes, Arthoniomycetes and Dothideomycetes] that exhibit high stress tolerance, yeast‑like or meristematic growth, and constitutive 1,8-dihydroxynaphthalene (DHN) melanin formation. They dominate a range of hostile natural and man‑made environments – from desert rocks and salterns to dishwashers, roofs, and solar panels. Due to their slow growth and the lack of sexual cycles and genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We consider the rock inhabitant K. petricola [Eurotiomycetes, Chaetothyriales] a suitable model for studying the phenotypic characteristics of black fungi. With K. petricola the regulation of pigment synthesis, general stress responses and the unusual modes of cell division can be dissected by advanced reverse and forward genetics approaches. The genome of K. petricola strain A95 was sequenced using a combination of short high quality Illumina reads and long PacBio reads. The final assembly consists of twelve contigs: five complete chromosomes and six contigs with one telomer each. Gene annotation supported by transcriptomics and proteomics data was manually curated. Recently, we developed a set of genetic tools to manipulate the genome for analyzing gene functions and studying the cell biology. This set includes CRISPR/Cas9-based genome editing and live-cell imaging using genetically encoded fluorescent proteins, as well as protocols for -omics approaches and for simulation of mineral weathering in the laboratory. Mutants defective in DHN melanogenesis, carotenogenesis or both processes are currently studied to elucidate the role of these protective pigments in tolerance of natural and man-made stresses, weathering of olivine, penetration of marble, and adhesion to surfaces. Further, the established protocols and knowledge gained from K. petricola form a starting point for making other extremotolerant black fungi accessible to genetic manipulation.
Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Sunlight-associated stresses are however multiple: high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses. Ascomycota dominating light-flooded habitats accurately sense and respond to changes in light using it as a cue to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships. Two species from two light-flooded habitats – phyllosphere and sun-exposed solid surfaces – were analysed for their photoreceptor distribution.
In both habitats phototroph-associated and black [dihydroxynaphthalene (DHN) melanin-containing] fungi are prevalent. This diversity was sampled with the plant-associated fungus Botrytis cinerea (Leotiomycetes), while Knufia petricola (Eurotiomycetes) was included as a typical biofilm-former on sun-exposed solid surfaces e.g. rocks, building facades, roofs, and solar panels. The analysis has shown that genomes of black fungi contain more photoreceptors than animal pathogens and saprophytes such as Aspergillus nidulans and Neurospora crassa1,2. B. cinerea that causes the grey mould disease by infecting the above-ground parts of more than 200 dicots has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts1.
Rock-inhabiting Dothideomycetes and Eurotiomycetes including Knufia petricola possess equal numbers of photoreceptors along with the same set of protective metabolites i.e. melanin, carotenoids and mycosporines2. This similarity between black fungi from plant and rock surfaces suggests that photoperception and -regulation are important for sun-stressed fungi that receive nutrients through cooperation with phototrophs. CRISPR/Cas9-based genetic tools for manipulating K. petricola were established3 and are currently used for elucidating the functions of the different photoreceptors in the biology of rock-inhabiting fungi.
This work was supported by the grant SCHU 2833/4-1 from the German Research Foundation (DFG) and internal funds of the BAM.
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.
Dihydroxynaphthalene (DHN) melanin is produced by different Ascomycetes via slightly differing biosynthetic routes. The polyketide synthases (PKS) release the heptaketide YWA1, the hexaketide AT4HN or the pentaketide T4HN. The first two products are deacetylated by ‘yellowish-green’ hydrolases to T4HN, and T4HN is further converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases. DHN melanogenesis is often regulated in a spatial and temporal fashion resulting e.g. in melanized reproduction, survival and/or infection structures. Remarkable is the regulation of the DHN melanogenesis in the foliar plant pathogen Botrytis cinerea: it involves two differently expressed PKSs providing the precursor in conidia and sclerotia, respectively (Schumacher 2016, Mol Microbiol). In contrast, a polyphyletic group of Ascomycetes (microcolonial fungi/ black yeast) dwelling in hostile habitats such as bare rock surfaces in hot and cold deserts, exhibits constitutive melanogenesis. Here, DHN melanin builds a protective layer around all vegetative cells thus contributing to the survival of diverse environmental stresses even without specialized reproduction structures. As part of our continuing research on microcolonial rock-inhabiting fungi, we chose the genetically amenable Knufia petricola strain A95 (Nai et al. 2013, Fungal Genet Biol; Noack-Schönmann et al. 2014, AMB Express) for detailed studies. DHN-deficient mutants generated by targeted mutation of biosynthetic genes were studied with regard to the architecture of the cell wall and the EPS (extracellular polymeric substances) matrix, attachment to and weathering of olivine, as well as the tolerance to abiotic and biotic stresses. We will discuss the critical role of the outer cell surface (DHN melanin and EPS) in adhesion to the substrate and subsequent damage of the colonized surface.
Microcolonial black fungi, a polyphyletic group of ascomycetes, exhibit constitutive melanin formation, yeast-like growth and high stress tolerances. They dominate – often together with bacteria and algae in sub-aerial biofilms – a range of hostile environments including natural and man-made ones, from salterns to dishwashers, roofs and solar panels. Because of lacking genetic tools and the slow growth of most isolates, the genetic bases for these specific properties are largely unknown. The rock-inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales) exhibits all characteristics of microcolonial black fungi and was selected as recipient for genetic engineering to study gene functions and genetic interactions. Different variants of green and red fluorescent proteins were successfully expressed indicating that fluorescence microscopy using genetically encoded fluorescent proteins and fluorescent dyes enables various cell biology approaches. Furthermore, genes of biosynthetic pathways (DHN melanin, carotenoids, uracil, adenine) were successfully mutated by applying traditional gene replacement and plasmid-based or ribonucleoprotein (RNP)-based CRISPR/Cas9 or silenced by RNA interference (RNAi). The availability of this advanced and efficient genetic toolbox and the annotated genome sequence of strain A95 makes K. petricola an excellent model for exploring the secrets of microcolonial black fungi.
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.
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.
Rock-EATING FUNGI - Genetic Dive into the Biology of the Microcolonial Black Fungus Knufia petricola
(2021)
Microcolonial black fungi are a group of ascomycetes that exhibit high stress tolerance, yeast‑like growth and constitutive melanin formation. They dominate a range of hostile natural and man‑made environments, from desert rocks and salterns to dishwashers, roofs and solar panels. Due to their slow growth and a lack of genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We chose to address this gap by genetically engineering the rock‑inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales), a species that exhibits all characteristics of black fungi. The state‑of‑the‑art genetic toolkit, together with the annotated genome sequence of strain A95, firmly established K. petricola as a model for exploring microcolonial black fungi.
The exponential rise in the number of fungal genomes sequenced by next-generation sequencing techniques makes it necessary to increase efforts to correctly annotate and assign gene functions. There are two possibilities to explore a genome and its gene functions. The hypothesis-based method proves the function of already existing gene/allele candidates by targeted mutagenesis - so called reverse genetics. The basis of forward genetics approaches is the random mutagenesis of the genome, followed by screening of obtained mutants for the phenotype of interest, and identification of the mutated genes in the respective mutants. This strategy is hypothesis-generating, means it is necessary to verify the relationship between the detected mutations and the observed phenotype by targeted mutagenesis of the identified gene. We developed a toolbox for editing the genome of the rock inhabitant Knufia petricola [Eurotiomycetes, Chaetothyriales] that allows the study of the phenotypic characteristics of black fungi such as the regulation of pigment synthesis, general stress responses, oligotrophy, and the unusual modes of cell division by advanced reverse and forward genetics approaches. The toolbox includes the annotated genome sequence of strain A95, efficient strategies for CRISPR/Cas9-based genome editing and live-cell imaging using genetically encoded fluorescent proteins, as well as protocols for -omics approaches and for simulation of mineral weathering. A forward genetics approach using transposon mutagenesis is currently developed for identifying essential genes. The established protocols and knowledge gained from K. petricola form a starting point for making other fungi from extreme environments accessible to genetic manipulation.
Dihydroxynaphthalene (DHN) melanin is produced by diverse Ascomycetes via slightly differing biosynthetic routes. The polyketide synthases (PKS) release the heptaketide YWA1, the hexaketide AT4HN or the pentaketide T4HN. The first two products are deacetylated by ‘yellowish-green’ hydrolases to T4HN, and T4HN is further converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases. DHN melanogenesis is often regulated in a spatial and temporal fashion resulting e.g., in melanized reproduction and survival structures of the foliar plant pathogen Botrytis cinerea (Schumacher 2016, Mol Microbiol). In contrast, a polyphyletic group of Ascomycetes (microcolonial fungi/ black yeasts) dwelling in hostile habitats such as bare rock surfaces in hot and cold deserts, exhibits constitutive melanogenesis. Here, DHN melanin builds a protective layer around all vegetative cells thus contributing to the survival of diverse environmental stresses even without specialized reproduction structures. For studying the relevance of constitutive DHN melanogenesis for tolerance of abiotic and biotic stresses, adhesion to substrates and subsequent damage of colonized surfaces, the rock-inhabiting fungus Knufia petricola was chosen as gene functions in this fungus can be studied by CRISPR/Cas9-based genome editing. The putative melanogenic genes were identified in the genome of K. petricola, deleted to confirm their involvement in DHN melanogenesis and co-expressed in Saccharomyces cerevisiae for reconstruction of the synthesis pathway. Phenotypes of DHN-deficient mutants are studied. Here, we will discuss the role of the DHN melanin layer on the outer cell wall in tolerating UV irradiation.
The roles of DHN melanin and the stress-activated MAP kinase in the rock inhabitant Knufia petricola
(2023)
Black fungi/yeasts exhibit high stress tolerance, yeast‑like or meristematic growth, and constitutive 1,8-dihydroxynaphthalene (DHN) melanin formation. Due to their slow growth, robust cell walls and the lack of sexual cycles and genetic tools, the underlying mechanisms of their phenotypic traits have remained largely unexplored. Using recently developed genetic tools, it is now possible to manipulate the genome of the rock-inhabiting model fungus Knufia petricola. Thus, gene functions and the cell biology of black fungi can be studied using CRISPR/Cas9-based genome editing and live-cell imaging with genetically encoded fluorescent proteins. Here, we are addressing the question to which extent constitutive pigment formation (melanin and carotenoids) and responses mediated by the stress-activated mitogen-activated protein (MAP) kinase contribute to the observed extremotolerance of K. petricola. The mutations of pks1, phs1 and both genes result in melanin-free (pink), carotenoid-free (black) and pigment-free (white) strains, respectively. The other putative melanogenic genes were identified in the genome, deleted to confirm their involvement in DHN melanogenesis and co-expressed in Saccharomyces cerevisiae for reconstruction of the synthesis pathway. Sak1 encoding the stress-activated MAP kinase was deleted in the wild-type and different pigment-deficient backgrounds. Growth of the obtained single, double and triple deletion mutants was tested by droplet tests on media supplemented with different stress-inducing agents. The Δsak1 mutants show slightly reduced growth rates even without environmental pressure and are hypersensitive to different stresses: e.g. osmotic, oxidative, membrane, pH and heat stress. Melanin-free Δsak1 mutants are more sensitive than black Δsak1 mutants to some but not all stress conditions, suggesting that melanin and the SAK1 pathway have complementary roles in protecting K. petricola from stress.
Sunlight is an almost unavoidable environmental cue and plays a fundamental role in the biology of pro- and eukaryotic organisms. To cope with sunlight-associated stresses e.g., high temperatures, UV radiation, accumulation of reactive oxygen species, desiccation, and osmotic stress, it is important for organisms to accurately sense and respond to changes in light. The benefits of light are obvious for green organisms such as cyanobacteria, algae and plants which use light as an energy source (photosynthesis). Fungi that can share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Examples are the plant pathogen Botrytis cinerea, the gray mold fungus, and the rock inhabitant Knufia petricola, a microcolonial black fungus which forms multispecies biofilms with bacteria and algae.
Gegenstand der vorzustellenden Arbeiten 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 Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. 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. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Environmental sustainability and –stability of Materials concerning the Migration of pollutants
(2018)
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long-term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer-based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.