TY - CONF A1 - Ulbricht, Alexander T1 - Do Microbes like Additively Manufactured Aluminium? N2 - The use of laser-additively manufactured metallic components in the industrial sector is gaining traction, with the process now entering its application phase. Consequently, the materials are exposed to corrosive microbes, which this study examines in order to determine the implications of this exposure. Specifically, the study examines the exposure of laser powder bed fused AlSi10Mg (PBF-LB/AlSi10Mg) components to sulphate-reducing bacteria in an anaerobic environment. Is the specific PBF-LB microstructure a potential factor in determining or aiding biocorrosion? A prismatic specimen was exposed to sulphate-reducing bacteria (SRB) for two weeks. The sample was scanned by X-ray computed tomography (XCT) before and after SRB exposure. The two data sets were registered to each other (using the internal void distribution as markers, due to the corrosion of the specimen’s surface) to enable the evaluation of the corrosion damage. Virtual cuts of the 3D XCT reconstructions show a loss of volume and localised damage. The damage distribution aligns with the hatching pattern of laser exposure from laser powder bed fusion. T2 - Konferenz iCT 2026 CY - Linz, Austria DA - 10.02.2026 KW - Computed tomography KW - Biokorrosion KW - Additive manufacturing KW - PBF-LB KW - Laser powder bed fusion KW - Sulphate-reducing bacteria PY - 2026 AN - OPUS4-65570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Julseth, Mara Jean T1 - Multivalent Myteries: How Termite Chromosome Chains Shape Evolution N2 - Termites challenge long-standing assumptions about insect social evolution. One important difference compared to the social ants, bees and wasps lies in their chromosomes: termites are diploid, with X/Y sex differentiation observed in most species and males playing active roles across all castes and life stages. Adding to their uniqueness, termites exhibit multivalent chromosome chains during male meiosis—an intriguing and seldom seen feature of eukaryote evolution. These chains, in addition to other chromosomal formations, such as bivalent rings and rods, may serve to suppress recombination, thereby mitigating against the potentially harmful effects of inbreeding. Again, this positions termites as an important contrasting study system to other social insect groups, where recombination rates tend to be elevated. Multivalent chromosome chains may also play a significant role in speciation processes by increasing the likelihood of chromosomal translocations and promoting genomic islands of divergence. In European Reticulitermes, variability in chain length and stability both between and within species provides a compelling model system for studying the evolutionary importance of multivalent chromosome chains at intra- and interspecific levels and at different evolutionary time scales. To investigate these dynamics, we collected over 200 colonies of Reticulitermes species across the Mediterranean, generating de novo reference genomes, comprehensive population genomic as well as karyotypic data from three recently diverged species. Our findings shed light on the intricate relationship between chromosomal architecture and evolutionary mechanisms in termites, offering new insight into how genome structure shapes species evolution. T2 - ESEB 2025 Congress CY - Barcelona, Spain DA - 17.08.2025 KW - Termites KW - Chromosome evolution PY - 2025 AN - OPUS4-65059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dehkohneh, Abolfazl T1 - Effect of Carbon and Nitrogen on Growth of the Oligotrophic and Extremotolerant Fungus Knufia petricola N2 - Introduction: Rock-inhabiting black fungi are renowned for their constitutive melanin production, extremotolerance and ubiquitous colonization of oligotrophic, natural or anthropogenic subaerial surfaces, including marble monuments and solar panels. Knufia petricola is a model for these fungi as it is genetically amenable and has their typical characteristics. It is capable of colonizing and deteriorating minerals and produces extracellular polymeric substances that facilitate attachment. Objectives: The objective of this study is to understand how such an organism is able to grow in environments depleted of C and/or N. Method: K. petricola growth parameters (colony extension and thickness, biomass, CO2 respiration and carbon-use efficiency (CUE)) were analysed for different C to N ratios (C:N), changing both the C and N concentrations and sources. The study utilized a dual-scale approach, examining biofilm formation on agar (macroscale) and growth of a single cell into a microcolony in a microfluidic device (microscale). This methodology provided insights into the nutritional requirements and growth behaviours of K. petricola across different spatial scales. Findings: Our macroscale analysis indicated optimal growth at the C:N ratio of 60. The morphological analysis demonstrated that when nitrate is utilized as the N source, colonies tend to exhibit filamentous growth at their edges, especially when glucose is available as C source. In contrast, when ammonium is the N source, the colony surface appears smooth (Fig. 1A). Moreover, C or N depletion led to higher substrate penetration, mostly through filaments at the edge of the biofilm. Notably, the lowest carbon concentration yielded reduced biomass C:N ratio and the peak biomass C:N ratio was observed at the medium C:N ratio of 60, suggesting a potential correlation between C:N ratio and optimal growth (Fig. 1B). The CUE was however quite low, ca. 0.4-0.6, being lowest when C and N were limiting. Concurrently, microscale analyses of single cells revealed that increasing the C:N ratio from 0.6 to 60 caused (1) shorter cell cycles and (2) more branching, no branching formed without C and N (Fig. 1C). This led to a denser colony at optimal conditions and a rather extended morphology under C or N limitations. Conclusion: The findings demonstrate that the depletion of either carbon or nitrogen results in enhanced substrate penetration, predominantly through edge filaments. Notably, the optimal growth and peak biomass C:N ratio of 60 suggest both a correlation with and importance of the medium C:N ratio. Specifically, the lowest carbon input led to a reduced biomass C:N ratio, while the peak biomass C:N ratio was achieved at the medium C:N ratio of 60. T2 - FEMS MICRO conference CY - Milano, Italy DA - 14.07.2025 KW - Black fungi KW - Carbon-use efficiency KW - Polyextremotolerant KW - Oligotrophs KW - Rock-inhabiting fungi PY - 2025 AN - OPUS4-65038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Davenport, Rebecca T1 - Regulations versus practice and the Divine Name: Ink analysis in medieval Torah scrolls N2 - The medieval Rabbis had very strict rules for the construction of a Sefer Torah. The Divine Names should be written • by a qualified scribe • who is ritually pure • in the presence of a minyan (10 adult Jewish men) • in an appropriate frame of mind • without being interrupted However, when these scrolls were written it would have been impossible to verify any of this after the fact. While we do not currently have any way to determine how recently the scribes had bathed, or what they might have been thinking as they wrote, we can now know much more about the inscription of the Divine Name than these scribes ever would have guessed. It is sometimes apparent from a visual inspection of the text that the Divine Name has been written in a second stage, from irregular letter kerning or a different ink colour. Using XRF, we have been able to discover more instances of a different ink used for the Name, and have shown that in some cases the secondary ink was also used to correct the main text, suggesting that the later writing was done by a master scribe who also proofread the entire scroll. Using a Brucker M6 Jetstream, it has been possible to produce elemental “heat maps” of whole paragraphs or even large sections of a parchment sheet. Using such large samples of text, we can usefully compare the levels of copper and zinc used to write individual letters or words despite their relatively low concentration, which permits very fine differentiation of the inks used. The techniques presented here would also be highly applicable to assessing ink degradation, as they are able to detect much smaller differences in ink composition than had previously been possible. T2 - The International Iron Gall Ink Meeting 2025 CY - Lisboa, Portugal DA - 07.05.2025 KW - XRF spectroscopy KW - Torah scrolls KW - Jewish studies KW - XRF mapping PY - 2025 AN - OPUS4-65036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kalbe, Ute T1 - Assessment of Microplastic and Contaminant Emissions from Artificial Turf Sports Pitches N2 - Due to their advantages over natural gras, artificial turf sports pitches are well established in popular sports and their number is increasing every year. This raises questions about potential pollutant emissions and possible risks to the environment due to its transfer to soil and groundwater. The main sources of emissions are the rubber infill granules and the abrasion of grass fibers. While estimates on the transfer of pollutants to the soil are already available, there is still insufficient data on the discharge of microplastics from artificial turf systems and thus on the assessment of its relevance for the soil. To close this gap, the pollutant emissions of three artificial turf scenarios - past (fossil-based, rubber infill), present (most frequently installed in Germany, rubber infill) and future (turf with recycled grass fibers, no rubber infill) - were compared in different ageing states (unaged, accelerated, and real time aged). Accelerated ageing consisting of UV weathering and mechanical stress was applied to simulate the outdoor weathering of turf systems during their service life span of approx. 15 years. Emissions of microplastics and environmentally relevant pollutants were sampled simultaneously using newly developed, innovative lysimeters. The microplastics contents were determined using Thermal Extraction-Desorption Gas Chromatography/Mass Spectrometry (TED-GC/MS). In addition, the concentrations of PAH and heavy metals were determined. T2 - Jahrestag der Deutschen Bodenkundlichen Gesellschaft CY - Tübingen, Germany DA - 14.09.2025 KW - Artificial Turf KW - Microplastics KW - Contaminants PY - 2025 AN - OPUS4-65022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Martens, Birte T1 - The evolution of symbiont and immune system interactions in Blattodea N2 - Immunity plays an important role in evolutionary ecology. The immune system interacts with both pathogens, which can act as important selective forces, and symbionts, which are regulated by the host‘s immune system and also can play a role in the host‘s immune defenses. The Blattodea consist of what is commonly known as cockroaches and the termites, who are themselves specialized eusocial cockroaches. Blattodea have two symbiont types that are characteristic to either the cockroaches or the termites (Table 1). These symbiont transitions open up the opportunity to characterize and investigate host-symbiont-pathogen interactions and how they evolved in Blattodea. T2 - Insect Infect Meeting 2025 CY - Berlin, Germany DA - 07.04.2025 KW - Evolution KW - Cockroaches KW - Immunity KW - Symbionts KW - Host-Symbiont-Interactions PY - 2025 AN - OPUS4-64970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Martens, Birte T1 - The evolution of symbiont and immune system interactions in Blattodea N2 - Immunity plays an important role in evolutionary ecology. The immune system interacts with both pathogens, which can act as important selective forces, and symbionts, which are regulated by the host‘s immune system and can also play a role in the host‘s immune defenses. The Blattodea consist of what is commonly known as cockroaches and the termites, who are themselves specialized eusocial cockroaches. Blattodea have two symbiont types that are characteristic to either the cockroaches or the termites (Table 1). These symbiont transitions open up the opportunity to characterize and investigate host-symbiont-pathogen interactions and how they evolved in Blattodea. T2 - Ecological Immunology Workshop 2025 CY - Joachimsthal, Germany DA - 15.09.2025 KW - Evolution KW - Cockroaches KW - Immunity KW - Symbionts KW - Host-Symbiont-Interactions PY - 2025 AN - OPUS4-64971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian T1 - Development, Validation and Application of an Accelerated Weathering Protocol for Assessing Bisphenol A Release from Polycarbonate Materials into the environment N2 - Bisphenol A (BPA) is under continuous regulatory scrutiny and listed as substance of very high concern (SVHC). Particular concern is related to its frequent detection in surface waters, despite being readily biodegradable. Several studies have been conducted to investigate sources and pathways of BPA in the environment, concluding that its main use as monomer in polycarbonate (PC) contributes only marginally to environmental BPA releases over its life cycle. To better understand the actual releases of BPA from PC under environmental conditions, a newly developed methodology (Federal Institute for Materials Research and Testing, BAM) was applied, which comprises a novel accelerated weathering protocol for polycarbonate (PC) materials, combined with an advanced analytical setup allowing for improved detection of BPA at trace level concentrations. The weathering protocol achieves a 13.6-fold acceleration compared to Central European outdoor conditions and simulates environmental stressors (global radiation, rain, temperature variations) in a laboratory weathering chamber, with simultaneous BPA release measurements using an organic isotope dilution calibration LC-MS/MS approach. Validation was performed in parallel outdoor exposure tests, by using haze and yellowness index measurements as reference parameters. PC sample types representative of major polycarbonate applications were examined: Samples with different levels of UV-protection as used in transparent sheets used outdoor in construction or housings in Electro- and Electronic applications as well as samples with a protective coating as used in automotive applications (headlamps, glazing and construction). Results demonstrated consistently low total BPA releases of around 0.3 mg m⁻² for samples with exposed PC surfaces, while releases from coated samples were significantly reduced by around two orders of magnitude. In all cases examined, the BPA release ceased to zero after a period of four to six weeks, equivalent to approximately 1 to 1.5 years of outdoor exposure. This suggests that potential BPA releases diminish to virtually zero after that timespan. While the newly developed test method is not suitable for routine laboratory implementation, it provides crucial quantitative data on BPA release from PC materials during accelerated environmental weathering. T2 - Umwelt 2025 CY - Dessau, Germany DA - 22.09.2025 KW - Bisphenol A KW - Polycarbonate KW - Weathering PY - 2025 AN - OPUS4-64665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kanaris, Orestis T1 - Consequences of benzalkonium chloride tolerance on the development of antibiotic resistance in E. coli N2 - Biocides are used in large amounts in industrial, medical, and domestic settings. Benzalkonium chloride (BAC) is a commonly used biocide, for which previous research revealed that Escherichia coli can rapidly adapt to tolerate BAC-disinfection, with consequences for antibiotic susceptibility. However, the consequences of BAC-tolerance for selection dynamics and resistance evolution to antibiotics remain unknown. Here, we investigated the effect of BAC-tolerance in E. coli on its response upon challenge with different antibiotics. Competition assays showed that subinhibitory concentrations of ciprofloxacin - but not ampicillin, colistin and gentamicin - select for the BAC-tolerant strain over the BAC-sensitive ancestor at a minimal selective concentration of 0.0013-0.0022 µg∙mL-1. In contrast, the BAC-sensitive ancestor was more likely to evolve resistance to ciprofloxacin, colistin and gentamicin than the BAC-tolerant strain when adapted to higher concentrations of antibiotics in a serial transfer laboratory evolution experiment. The observed difference in the evolvability of resistance to ciprofloxacin was partly explained by an epistatic interaction between the mutations conferring BAC-tolerance and a knockout mutation in ompF encoding for the outer membrane porin F. Taken together, these findings suggest that BAC-tolerance can be stabilized in environments containing low concentrations of ciprofloxacin, while it also constrains evolutionary pathways towards antibiotic resistance. T2 - µClub Seminar CY - Berlin, Germany DA - 23.05.2025 KW - Biocides KW - AMR KW - Resistance evolution PY - 2025 AN - OPUS4-64658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters! N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface, and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Bacterial adhesion KW - Biofilm KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses PY - 2025 AN - OPUS4-64632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -