TY - CONF A1 - Stawski, Tomasz A1 - Van Driessche, A. T1 - Particle-mediated origins of mesocrystalline disorder in calcium sulfate single crystals N2 - Calcium sulfate minerals are abundant in natural and engineered environments and they exist in the form of three hydrates: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of these calcium sulfate phases from aqueous solution have been the subject of intensive research1. The state-of-the-art of the calcium sulfate formation mechanisms builds upon and goes beyond what we have come to appreciate in the astounding intricacy of other mineral formation processes from ions in aqueous solutions. The original, and rather naive, 'textbook' image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species2. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. In this context, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of the different crystalline phases involves several steps including a common amorphous precursor1, 3, 4. In this contribution we show that the formation of the amorphous phase involves the aggregation of small primary particles into larger disordered aggregates exhibiting a "brick-in-the-wall" structure5, 6. The actual crystallization occurs by the restructuring and coalescence of the particles ("bricks") into a given calcium sulfate phase depending on the physicochemical conditions of the solution. Importantly, the rearrangement process does not continue until a (nearly-)perfect homogeneous single crystal is obtained. Instead it comes to a stop, or at least significantly slows down. Such a process thus yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous crystal structure, within which the domains are separated by an amorphous (i.e. less ordered) calcium sulfate phase. Hence, the non-classical crystallization process of CaSO4 yields a final imperfect mesocrystal with an overall morphology resembling that of a single crystal, yet composed of smaller nano-domains. Importantly, these observations reveal that organic-free calcium sulfate mesocrystals grown by a particle mediated-pathway preserve in the final crystal structure a “memory” or “imprint” of their non-classical nucleation process, something that has been overlooked until now. Furthermore, the nano-scale misalignment of the structural sub-units within these crystals can propagate through the length-scales, and be expressed macroscopically as misaligned zones/domains in large single crystals. Indeed, by considering large anhydrite crystals from the famous Naica Mine (“Cueva de los cristales”) we observed a suite of correlated self-similar void defects spanning multiple length-scales7. These flaws, in the macroscopic crystal, stem from “seeds of imperfection” originating from a particle-mediated nucleation pathway. Hence, building a crystal could be viewed as Nature stacking blocks in a game of Tetris, whilst slowly forgetting the games core concept and failing to fill rows completely. T2 - ECCG: European Conference on Crystal Growth 7 CY - Paris, France DA - 25.07.2022 KW - Anhydrite KW - SAXS KW - Single crystal KW - Mesocrystal PY - 2022 AN - OPUS4-56276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bucar, K. A1 - Zitnik, M. A1 - Stabile, L. A1 - Ozan, J. A1 - Seeger, Stefan T1 - Performance of a Sharp GP2Y low-cost aerosol PM sensor N2 - Simple particulate matter sensors are gaining popularity due to their low price, easy handling and good temporal resolution. In this presentation, we report on the performance of a Sharp optical PM sensor GP2Y1010AU0F, which costs less than 15 €. The sensor is built around an infrared emitting diode (ILED) and a phototransistor detecting the light scattered from the aerosol particle. An electronic circuit shapes the detected light in a pulsed signal. The manufacturer advises sampling the output signal 280 microseconds after the ILED pulse. The measured output voltage is an indicator of dust concentration. We have built two identical simple PM monitoring devices using Raspberry Pi 3 computer interfacing the PM sensor with Microchip’s MCP3002 ADC via SPI. The ADC is capable of more than 100 ksamples/s at 10-bit resolution. The Rpi3 was pulsing the sensor at 10Hz, digitizing and saving the data and sending the results wirelessly. Sensor’s output pulse shape was sampled with 10 microsecond time steps and saved, thus making offline analysis possible. A time jitter of output pulses can be observed and suggests a peak fitting as a better approach to the signal readout compared to the single sampling at a fixed time after pulse triggering We compared both methods. T2 - European Aerosol Coference EAC 2019 CY - Gothenburg, Sweden DA - 25.08.2019 KW - Aerosol KW - Low cost aerosol PM sensor KW - PM PY - 2019 AN - OPUS4-49581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas A1 - Kanaris, Orestis A1 - Schmidt, Selina A1 - Schreiber, Frank T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - A presentation given at the VAAM conference 2022, summarizing our findings published in the research paper "Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection" T2 - Annual conference of the association for general and applied microbiology (VAAM) 2022 CY - Düsseldorf, Germany DA - 21.02.2022 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance KW - Disinfection PY - 2022 AN - OPUS4-54437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rühle, Bastian A1 - Bresch, Harald A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan A1 - Radnick, Jörg T1 - Perspektive der BAM auf neuartige Materialien N2 - Neuartige Materialien, die bekannte (Werk-)Stoffe mit neuen Funktionalitäten ausstatten, spielen eine zunehmend wichtige Rolle im Bereich der Materialforschung und -prüfung. Das Spektrum neuartiger Materialien reicht von der gezielten Oberflächenfunktionalisierung und -strukturierung makroskopischer Materialien, dünnen Beschichtungen bis hin zu mikro- und nanoskaligen Kompositmaterialien und funktionalen Materialien an der Schnittstelle zur Biologie, Biotechnologie, nachhaltige Energiespeicherung und Sensorik. Dabei bieten neuartige Materialien die Chance, Werkstoffe und Produkte mit erweiterter oder verbesserter Funktionalität zu erhalten und Sicherheit bereits im Designprozess zu berücksichtigen. Durch dieses breite Anwendungsspektrum und die Herausforderungen, die solche Materialien für die Sicherheit in Chemie und Technik mit sich bringen, sind diese in allen Themenfeldern der BAM repräsentiert (Material, Analytical Sciences, Energie, Infrastruktur und Umwelt). Die Aufgaben der BAM erstrecken sich dabei von der Herstellung von Referenzmaterialien für Industrie, Forschung und Regulation, über die Erstellung von standardisierten Referenzverfahren für nachhaltige Messungen im Umwelt- und Lebenswissenschaftsbereich bis hin zur Bereitstellung von belastbaren und zitierbaren Referenzdaten. Durch die genaue Charakterisierung neuartiger Materialien können potentiell problematische Substanzen identifiziert und deren Risiken besser abgeschätzt werden. In diesem Beitrag werden einige aktuelle Beispiele aus diesen Bereichen vorgestellt. T2 - NanoDialog der Bundesregierung - Chancen und Risiken von Neuartigen Materialien CY - Berlin, Germany DA - 22.05.2019 KW - Advanced Materials KW - Nanomaterialien KW - Neuartige Materialien PY - 2019 AN - OPUS4-49594 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Phenotypic diversity in microbial metabolism and antimicrobial resistance N2 - Most microorganisms live in environments where nutrients are limited and fluctuate over time. Cells respond to nutrient fluctuations by sensing and adapting their physiological state. Recent studies suggest phenotypic heterogeneity in isogenic populations as an alternative strategy in fluctuating environments, where a subpopulation of cells express a function that allows growth under conditions that might arise in the future. It is unknown how environmental factors such as nutrient limitation shape phenotypic heterogeneity in metabolism and whether this allows cells to respond to nutrient fluctuations. Here, we show that substrate limitation increases phenotypic heterogeneity in metabolism, and this heterogeneity allows cells to cope with substrate fluctuations. We subjected the N2-fixing bacterium Klebsiella oxytoca to different levels of substrate limitation and substrate shifts, and obtained time-resolved single-cell measurements of metabolic activities using nanometre-scale secondary ion mass spectrometry (NanoSIMS). We found that the level of NH4+ limitation shapes phenotypic heterogeneity in N2 fixation. In turn, the N2 fixation rate of single cells during NH4+ limitation correlates positively with their growth rate after a shift to NH4+ depletion, experimentally demonstrating the benefit of heterogeneity. The results indicate that phenotypic heterogeneity is a general solution to two important ecological challenges - nutrient limitation and fluctuations - that many microorganisms face. Currently, we use NanoSIMS to develop a new approach that defines functionally-relevant, phenotypic biodiversity in microbial systems. In the last part of my presentation, I will highlight why the concept of phenotypic diversity is relevant for the understanding of antimicrobial resistance. T2 - Berlin Seminar for Resistance Research at FU Berlin Veterinary Medicine CY - Berlin, Germany DA - 01.03.2018 KW - Antimicrobial Resistance KW - Metabolism KW - Phenotypic diversity PY - 2018 AN - OPUS4-44597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schreiber, Frank T1 - Phenotypic diversity in microbial metabolism and antimicrobial resistance N2 - Phenotypic dicersty can emerge in microbial metabolic activties and in persistence against antimicrobials. In this talk, I present two examples of phenotypic heterogeneity and discuss how they might be related. T2 - Workshop on Bacterial adaptation to antimicrobials: environmental, evolutionary and mechanistic aspects CY - FU Berlin, Germany DA - 17.04.2018 KW - Antimicrobial resistance KW - Metabolism KW - Phenotypic diversity PY - 2018 AN - OPUS4-46271 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas A1 - Schreiber, Frank T1 - Phenotypic heterogeneity in disinfection: sources and consequences for antimicrobial resistance N2 - A summary of projects here at BAM which investigate the influence of phenotypic heterogeneity on the outcome of disinfection and the influence on antimicrobial resistance. This presentation was given in the Theory Seminar of the Quantitative and Theoretical Biology group of Prof. Oliver Ebenhöh at HHU Düsseldorf T2 - Theory Seminar in the Quantitative and Theoretical Biology group at HHU Düsseldorf CY - Düsseldorf, Germany DA - 24.02.2022 KW - Disinfection KW - Biocides KW - Heterogeneity KW - Resistance PY - 2022 AN - OPUS4-54442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Photoperception in black fungi that share niches with green organisms N2 - 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. T2 - International Symposium on Fungal Stress (ISFUS) CY - Sao Jose dos Campos, Brazil DA - 19.05.2019 KW - Botrytis KW - carotenoids KW - Knufia KW - melanin KW - Nostoc PY - 2019 AN - OPUS4-48130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Photoperception in plant- and rock-associated black fungi N2 - 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. T2 - 19th Congress of the European Society for Photobiology CY - Online meeting DA - 30.08.2021 KW - Fungi KW - Light KW - Extreme environments PY - 2021 AN - OPUS4-53191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Photoregulation in Plant- & Rock-associated Black Fungi N2 - 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. T2 - Scientific Colloquium at the Department of Genetics, University of Seville CY - Seville, Spain DA - 24.10.2019 KW - Light sensing KW - Knufia petricola KW - Botrytis cinerea PY - 2019 AN - OPUS4-49637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -