TY - JOUR A1 - Kanaris, Orestis A1 - Sobisch, Lydia-Yasmin A1 - Gödt, Annett A1 - Schreiber, Frank A1 - Nordholt, Niclas T1 - Consequences of benzalkonium chloride tolerance for selection dynamics and de novo resistance evolution driven by antibiotics 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. 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. KW - AMR KW - Resistance evolution KW - Resistance selection PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653842 DO - https://doi.org/10.1038/s44259-025-00170-8 SN - 2731-8745 VL - 4 IS - 1 SP - 1 EP - 13 PB - Springer Science and Business Media LLC AN - OPUS4-65384 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dimitrijević, Stevan P. A1 - Dimitrijević, Silvana B. A1 - Koerdt, Andrea A1 - Ivanović, Aleksandra A1 - Stefanović, Jelena A1 - Stanković, Tanja A1 - Gerengi, Husnu T1 - Comparison of Corrosion Resistance of Cu and Cu72Zn28 Metals in Apricot Fermentation Liquid N2 - The production of fruit brandies is based on distilling fermented fruit juices. Distillation equipment is usually made of copper. In traditional manufacturing, it consists of a boiler (batch) distiller, a boiler (pot), a steam pipe, and a condenser, all of which are made of pure copper. This study determined the corrosion parameters for copper (Cu) and Cu72Zn28 (in wt%) alloy in fermented apricot juice at room temperature. The fermentation process examined in this research utilized natural strains of yeast and bacteria, supplemented by active dry yeast Saccharomyces cerevisiae strains. This research used the following methods: open circuit potential (OCP), linear polarization resistance (LPR), and Tafel extrapolation to identify corrosion parameters. Cu had a 3.8-times-lower value of corrosion current density than brass, and both were within the range of 1–10 μA·cm−2, with an excellent agreement between LRP and Tafel. This study proved that Cu is an adequate material for the distillation of fruit brandies from a corrosion perspective. Despite this, there are occasional reports of corrosion damage from the field. Significant corrosion impacts can arise, as evidenced by laboratory tests discussed in this paper. In the absence of a highly corrosive environment, this study indicates that, to some extent, microbiologically influenced corrosion (MIC) can influence the degradation of the equipment material. KW - MIC KW - Metall KW - Envitonment PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628911 DO - https://doi.org/10.3390/ma18061253 SN - 1996-1944 VL - 18 IS - 6 SP - 1 EP - 17 PB - MDPI AG AN - OPUS4-62891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kjaervik, Marit A1 - Ramstedt, M. A1 - Schwibbert, Karin A1 - Dietrich, P. M A1 - Unger, Wolfgang T1 - Comparative Study of NAP-XPS and Cryo-XPS for the Investigation of Surface Chemistry of the Bacterial Cell-Envelope N2 - Bacteria generally interact with the environment via processes involving their cell-envelope. Thus, techniques that may shed light on their surface chemistry are attractive tools for providing an understanding of bacterial interactions. One of these tools is Al Kα-excited photoelectron spectroscopy (XPS) with its estimated information depth of <10 nm. XPS-analyses of bacteria have been performed for several decades on freeze-dried specimens in order to be compatible with the vacuum in the analysis chamber of the spectrometer. A limitation of these studies has been that the freeze-drying method may collapse cell structure as well as introduce surface contaminants. However, recent developments in XPS allow for analysis of biological samples at near ambient pressure (NAP-XPS) or as frozen hydrated specimens (cryo-XPS) in vacuum. In this work, we have analyzed bacterial samples from a reference strain of the Gram-negative bacterium Pseudomonas fluorescens using both techniques. We compare the results obtained and, in general, observe good agreement between the two techniques. Furthermore, we discuss advantages and disadvantages with the two analysis approaches and the output data they provide. XPS reference data from the bacterial strain are provided, and we propose that planktonic cells of this strain (DSM 50090) are used as a reference material for surface chemical analysis of bacterial systems. KW - P. Fluorescens KW - Cryo XPS KW - NAP-XPS KW - DSM 5009 PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525640 DO - https://doi.org/10.3389/fchem.2021.666161 VL - 9 SP - Article 666161 PB - Frontiers CY - Switzerland AN - OPUS4-52564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barkeshli, Mandana A1 - Stephan, Ina A1 - Shevchuk, Ivan A1 - Soltani, Mojtaba T1 - Characteristics of Sizing Materials Used in Persian Medieval Manuscripts: Physical, Optical, Spectral Imaging, and Fungicidal Properties N2 - In this study, we investigated the diverse range of materials used for sizing in Iranian paper manuscripts during the Timurid (fifteenth century) to Safavid (sixteenth century) and Qajar (nineteenth century) periods. Our approach combined historical analysis with scientific examination of reconstructed sizings. We reconstructed 15 sizing materials based on identified Persian historical recipes and analysed their physical, optical, and spectral characteristics. Additionally, we assessed their behaviour against the mould fungus Aspergillus flavus. The results revealed distinctive properties for each sizing material, shedding light on their potential applications in paper preservation. Furthermore, our investigation demonstrated variations in hygroscopicity, thickness, grammage, and ash content post-sizing. The sizing materials also exhibited different effects on paper reflectance properties. Additionally, our study revealed insights into the impact of sizing on burnished papers, indicating that the mechanical process of burnishing did not significantly alter the chemical composition or spectral properties of the paper, with only minor changes in brightness observed in specific cases. All tested sizing materials supported varying levels of mould growth, indicating potential implications for paper conservation. Our findings provide valuable insights into the historical practices of Iranian paper sizing and offer practical considerations for the preservation of paper manuscripts. KW - Paper sizings KW - Persian historical recipes KW - Physical and optical characteristics KW - Fungicidal property KW - Spectral imaging PY - 2024 DO - https://doi.org/10.1080/00393630.2024.2342647 VL - 69 SP - 519 EP - 536 PB - Informa UK Limited AN - OPUS4-60159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Keshmiri, Hamid A1 - Cikes, Domagoj A1 - Samalova, Marketa A1 - Schindler, Lukas A1 - Appel, Lisa-Marie A1 - Urbanek, Michal A1 - Yudushkin, Ivan A1 - Slade, Dea A1 - Weninger, Wolfgang J. A1 - Peaucelle, Alexis A1 - Penninger, Josef A1 - Elsayad, Kareem T1 - Brillouin light scattering anisotropy microscopy for imaging the viscoelastic anisotropy in living cells N2 - Maintaining and modulating mechanical anisotropy is essential for biological processes. However, how this is achieved at the microscopic scale in living soft matter is not always clear. Although Brillouin light scattering (BLS) spectroscopy can probe the mechanical properties of materials, spatiotemporal mapping of mechanical anisotropies in living matter with BLS microscopy has been complicated by the need for sequential measurements with tilted excitation and detection angles. Here we introduce Brillouin light scattering anisotropy microscopy (BLAM) for mapping high-frequency viscoelastic anisotropy inside living cells. BLAM employs a radial virtually imaged phased array that enables the collection of angle-resolved dispersion in a single shot, thus enabling us to probe phonon modes in living matter along different directions simultaneously. We demonstrate a precision of 10 MHz in the determination of the Brillouin frequency shift, at a spatial resolution of 2 µm. Following proof-of-principle experiments on muscle myofibres, we apply BLAM to the study of two fundamental biological processes. In plant cell walls, we observe a switch from anisotropic to isotropic wall properties that may lead to asymmetric growth. In mammalian cell nuclei, we uncover a spatiotemporally oscillating elastic anisotropy correlated to chromatin condensation. Our results highlight the role that high-frequency mechanics can play in the regulation of diverse fundamental processes in biological systems. We expect BLAM to find diverse applications in biomedical imaging and material characterization. KW - Optical and magnetic materials KW - Atomic and molecular physics and optics KW - Electronic PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595125 DO - https://doi.org/10.1038/s41566-023-01368-w SN - 1749-4885 SN - 1749-4893 VL - 18 IS - 3 SP - 276 EP - 285 PB - Nature Publ. Group CY - London AN - OPUS4-59512 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nordholt, Niclas A1 - van Heerden, J. H. A1 - Bruggeman, F. J. T1 - Biphasic Cell-Size and Growth-Rate Homeostasis by Single Bacillus subtilis Cells N2 - The growth rate of single bacterial cells is continuously disturbed by random fluctuations in biosynthesis rates and by deterministic cell-cycle events, such as division, genome duplication, and septum formation. It is not understood whether, and how, bacteria reject these growth-rate disturbances. Here, we quantified growth and constitutive protein expression dynamics of single Bacillus subtilis cells as a function of cell-cycle progression. We found that, even though growth at the population level is exponential, close inspection of the cell cycle of thousands of single Bacillus subtilis cells reveals systematic deviations from exponential growth. Newborn cells display varying growth rates that depend on their size. When they divide, growth-rate Variation has decreased, and growth rates have become birth size independent. Thus, cells indeed compensate for growth-rate disturbances and achieve growth-rate homeostasis. Protein synthesis and growth of single cells displayed correlated, biphasic dynamics from cell birth to division. During a first phase of variable duration, the absolute rates were approximately constant and cells behaved as sizers. In the second phase, rates increased, and growth behavior exhibited characteristics of a timer strategy. These findings demonstrate that, just like size homeostasis, growth-rate homeostasis is an inherent property of single cells that is achieved by cell-cycle-dependent rate adjustments of biosynthesis and growth. KW - Bacterial cell cycle KW - Single cell microbiology KW - Bacillus subtilis KW - Growth-rate homeostasis KW - Biphasic growth PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510689 DO - https://doi.org/10.1016/j.cub.2020.04.030 VL - 30 IS - 12 SP - 2238 EP - 2247 PB - Cell Press AN - OPUS4-51068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brischke, C. A1 - Bollmus, S. A1 - Melcher, E. A1 - Stephan, Ina T1 - Biological durability and moisture ynamics of Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana) N2 - Numerous non-native tree species are given attention with respect to the reforestation of calamity areas in Europe. Among them, several species may form durable wood which can be used for outdoor applications, but differences in wood durability are expected between original and European growth sites. This study aimed at examining the biological durability against wooddestroying fungi and water permeability of German-grown Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana). The heartwood of both wood species was assigned to durability class 4 (DC 4, less durable) in soil contact and DC 1–4 (very to less durable) against wood-destroying basidiomycetes. However, according to the Meyer-Veltrup model, their material resistance dose was notably higher compared to the reference species Norway spruce (Picea abies), and the resulting service life of above ground structures should be a multiple of the reference. KW - Natural durability KW - Fungal decay KW - Moisture performance KW - Permeability KW - Resistance model KW - Water uptake PY - 2022 DO - https://doi.org/10.1080/17480272.2022.2101941 SN - 1748-0272 SP - 1 EP - 11 PB - Taylor & Francis CY - London AN - OPUS4-55490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Selina A1 - Rodríguez-Rojas, A. A1 - Rolff, J. A1 - Schreiber, Frank T1 - Biocides used as material preservatives modify rates of de novo mutation and horizontal gene transfer in bacteria N2 - Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution and transmission of AMR. Previous studies showed that de-novo mutagenesis and horizontal gene transfer (HGT) by conjugation or transformation – important processes underlying resistance evolution and spread - are affected by antibiotics, metals and pesticides. However, natural microbial communities are also frequently exposed to biocides used as material preservatives, but it is unknown if these substances induce mutagenesis and HGT. Here, we show that active substances used in material preservatives can increase rates of mutation and conjugation in a species- and substance-dependent manner, while rates of transformation are not increased. The bisbiguanide chlorhexidine digluconate, the quaternary ammonium compound didecyldimethylammonium chloride, the metal copper, the pyrethroid-insecticide permethrin, and the azole-fungicide propiconazole increase mutation rates in Escherichia coli, whereas no increases were identified for Bacillus subtilis and Acinetobacter baylyi. Benzalkonium chloride, chlorhexidine and permethrin increased conjugation in E. coli. Moreover, our results show a connection between the RpoS-mediated general stress and the RecA-linked SOS response with increased rates of mutation and conjugation, but not for all biocides. Taken together, our data show the importance of assessing the contribution of material preservatives on AMR evolution and spread. KW - Mutation rate KW - Horizontal gene transfer KW - Biocides PY - 2022 DO - https://doi.org/10.1016/j.jhazmat.2022.129280 SN - 0304-3894 VL - 437 SP - 1 EP - 13 PB - Elsevier CY - Amsterdam AN - OPUS4-55261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbrich, Adelina-Elisa A1 - An Stepec, Biwen Annie A1 - Wurzler, Nina A1 - Terol, E. C. A1 - Koerdt, Andrea A1 - Meermann, Björn T1 - Beyond corrosion: Development of a single cell-ICP-ToF-MS method to uncover the process of microbiologically influenced corrosion N2 - The development of the microbiologically influenced corrosion ( MIC ) -specific inductively coupled plasma-time of flight-mass spectrometry ( ICP-ToF-MS ) analytical method presented here, in combination with the investigation of steel-MIC interactions, contributes significantly to progress in instrumental MIC analysis. For this, a MIC-specific staining procedure was developed, which ensures the analysis of intact cells. It allows the analysis of archaea at a single cell level, which is extremely scarce compared to other well-characterized organisms. The detection method revealed elemental selectivity for the corrosive methanogenic strain Methanobacterium -affiliated IM1. Hence, the possible uptake of individual elements from different steel samples was investigated and results showed the cells responded at a single-cell level to the different types of supplemented elements and displayed the abilities to uptake chromium, vanadium, titanium, cobalt, and molybdenum from solid metal surfaces. The methods developed and information obtained will be used in the future to elucidate underlying mechanisms, compliment well-developed methods, such as SEM-EDS, and develop novel material protection concepts. KW - Single cell KW - Microbiological influenced corrosion MIC KW - Sc-ICP-ToF-MS KW - Method development KW - Ir DNA staining approach KW - Carbon steel corrosion PY - 2022 DO - https://doi.org/10.1093/mtomcs/mfac083 SN - 1756-591X VL - 14 IS - 11 SP - 1 EP - 15 PB - Oxford University Press CY - Oxford AN - OPUS4-56254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vareschi, Silvia A1 - Jaut, Valerie A1 - Vijay, Srinivasan A1 - Allen, Rosalind J. A1 - Schreiber, Frank T1 - Antimicrobial efflux and biofilms: an interplay leading to emergent resistance evolution N2 - The biofilm mode of growth and drug efflux are both important factors that impede the treatment of bacterial infections with antimicrobials. Decades of work have uncovered the mechanisms involved in both efflux and biofilm-mediated antimicrobial tolerance, but links between these phenomena have only recently been discovered. Novel findings show how efflux impacts global cellular physiology and antibiotic tolerance, underpinned by phenotypic heterogeneity. In addition efflux can mediate cell-to-cell interactions, relevant in biofilms, via mechanisms including efflux of signaling molecules and metabolites, signaling using pump components and the establishment of local antibiotic gradients via pumping. These recent findings suggest that biofilm antibiotic tolerance and efflux are closely coupled, with synergistic effects leading to the evolution of antimicrobial resistance in the biofilm environment. KW - Evolution KW - Efflux KW - Antibiotics KW - Biofilms KW - Antimicrobial resistance KW - Phenotypic heterogeneity PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632799 DO - https://doi.org/10.1016/j.tim.2025.04.012 SN - 0966-842X SP - 1 EP - 15 PB - Elsevier Ltd. AN - OPUS4-63279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stephan, Ina A1 - Dimke, Thomas A1 - Guterman, R. A1 - Smith, C. A. A1 - Cataldo, V. A. T1 - Antibacterial and degradable thioimidazolium poly(ionic liquid) N2 - New antibacterial agents are urgently required to fight the emergence of antibiotic-resistant bacteria. We recently synthesized the first thioimidazolium ionene, which has antibacterial properties and can degrade in various media. This dual functionality is crucial in order to limit the environmental impact of these biocides. We have found that our polymer is stronger than benzalkonium chloride (BAC) against Pseudomonas aeruginosa and also readily degrades in the presence of base, while remaining stable in acidic environments. These results highlight a new emerging class of antibacterial degradable polymers. KW - Ionic liquid KW - Antibacterial polymer KW - Amphiphilic polymer KW - Thioimidazolium KW - Degradable polymer KW - Polyioinic liquid PY - 2020 DO - https://doi.org/10.1021/acssuschemeng.0c02666 VL - 8 IS - 22 SP - 8419 EP - 8424 PB - ACS Publications AN - OPUS4-50982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hobmeier, K. A1 - Goëss, M. C. A1 - Sehr, C. A1 - Schwaminger, S. A1 - Berensmeier, S. A1 - Kremling, A. A1 - Kunte, Hans-Jörg A1 - Pflüger-Grau, K. A1 - Marin-Sanguino, A. T1 - Anaplerotic Pathways in Halomonas elongata: The Role of the Sodium Gradient N2 - Salt tolerance in the γ-proteobacterium Halomonas elongata is linked to its ability to produce the compatible solute ectoine. The metabolism of ectoine production is of great interest since it can shed light on the biochemical basis of halotolerance as well as pave the way for the improvement of the biotechnological production of such compatible solute. Ectoine belongs to the biosynthetic family of aspartate-derived amino-acids. Aspartate is formed from oxaloacetate, thereby connecting ectoine production to the anaplerotic reactions that refill carbon into the tricarboxylic acid cycle (TCA cycle). This places a high demand on these reactions and creates the need to regulate them not only in response to growth but also in response to extracellular salt concentration. In this work, we combine modeling and experiments to analyze how these different needs shape the anaplerotic reactions in H. elongata. First, the stoichiometric and thermodynamic factors that condition the flux distributions are analyzed, then the optimal patterns of operation for oxaloacetate production are calculated. Finally, the phenotype of two deletion mutants lacking potentially relevant anaplerotic enzymes: phosphoenolpyruvate carboxylase (Ppc) and oxaloacetate decarboxylase (Oad) are experimentally characterized. The results show that the anaplerotic reactions in H. elongata are indeed subject to evolutionary pressures that differ from those faced by other gram-negative bacteria. Ectoine producing halophiles must meet a higher metabolic demand for oxaloacetate and the reliance of many marine bacteria on the Entner-Doudoroff pathway compromises the anaplerotic efficiency of Ppc, which is usually one of the main enzymes fulfilling this role. The anaplerotic flux in H. elongata is contributed not only by Ppc but also by Oad, an enzyme that has not yet been shown to play this role in vivo. Ppc is necessary for H. elongata to grow normally at low salt concentrations but it is not required to achieve near maximal growth rates as long as there is a steep sodium gradient. On the other hand, the lack of Oad presents serious difficulties to grow at high salt concentrations. This points to a shared role of these two enzymes in guaranteeing the supply of oxaloacetate for biosynthetic reactions. KW - Metabolic flux analysis KW - Halophilic bacteria KW - Halomonas elongata KW - Metabolic modeling PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513124 DO - https://doi.org/10.3389/fmicb.2020.561800 VL - 11 SP - 561800 AN - OPUS4-51312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiebel, J. A1 - Noack, J. A1 - Rödiger, S. A1 - Kammel, A. A1 - Menzel, Friederike A1 - Schwibbert, Karin A1 - Weise, Matthias A1 - Weiss, R. A1 - Böhm, A. A1 - Nitschke, J. A1 - Elimport, A. A1 - Roggenbuck, D. A1 - Schierack, P. T1 - Analysis of three-dimensional biofilms on different material surfaces N2 - Biofilms cause complications and high costs in both industry and medicine. Of particular interest are bacterial infections of prosthetic materials, which usually cannot be eliminated due to the high antibiotic resistance known for bacteria forming biofilms. The search for new materials and coatings with lower colonization potential and antibacterial activity is of great importance to reduce biofilm formation. However, there is no standardized procedure to examine the colonization characteristics of bacteria in the Biofilm state in situ. Here, we describe an automated epifluorescence microscopy system for the semi-quantitative analysis of three-dimensional (3D) biofilms on various surfaces. To analyze adherent bacteria, three materials (glass, steel and titanium) were incubated with bacteria in a flow chamber system. After fluorescence staining of the bacteria, automated image capturing, quantification of the bacteria, measurement of the colonized area and determination of the 3D biofilm height were carried out by using novel software. Furthermore, the materials were examined for their surface topography using white light scanning interferometry. Titanium compared to glass showed a significantly higher number of adherent bacteria. We argue that this was due to the higher microroughness of titanium. The colonized area was in accordance with the number of adherent bacteria and was also significantly larger on titanium coupons compared to glass. Maximum 3D biofilm height on glass coupons was significantly lower compared to the ones on steel and titanium. This novel method enables the standardized, automated investigation of the colonization with bacteria on different materials. This approach can considerably support the characterization of new material surfaces and their innovative coatings by analyzing the amount of attached Bacteria and thickness of biofilms in situ and eliminates the need of conventional cultivation. KW - Biofilm KW - Bacterial adhesion KW - Biofilm quantification KW - Automated analysis PY - 2020 DO - https://doi.org/10.1039/D0BM00455C SP - 1 EP - 11 PB - Royal Society of Chemistry AN - OPUS4-50815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Varadarajan, A. A1 - Allan, R. A1 - Valentin, J. A1 - Castañeda Ocampo, O. A1 - Somerville, V. A1 - Buhmann, M. A1 - West, J. A1 - Skipp, Paul A1 - van der Mei, H. A1 - Ren, Q. A1 - Schreiber, Frank A1 - Webb, J. A1 - Pietsch, Franziska A1 - Ahrens, C. T1 - An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1 N2 - Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential Protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms. KW - Biofilms PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515108 DO - https://doi.org/10.1038/s41522-020-00154-8 VL - 6 IS - 1 SP - Article number: 46 PB - Springer Nature CY - Singapore AN - OPUS4-51510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koerdt, Andrea A1 - Gerengi, Husnu A1 - Kaya, Ertugrul A1 - M. Solomon, Moses A1 - Snape, Matthew T1 - Advances in the Mitigation of Microbiologically Influenced Concrete Corrosion: A Snapshot N2 - Concrete, a versatile construction material, faces pervasive deterioration due to microbiologically influenced corrosion (MIC) in various applications, including sewer systems, marine engineering, and buildings. MIC is initiated by microbial activities such as involving sulfate-reducing bacteria (SRB), sulfur-oxidizing bacteria (SOB), etc., producing corrosive substances like sulfuric acid. This process significantly impacts structures, causing economic losses and environmental concerns. Despite over a century of research, MIC remains a debated issue, lacking standardized assessment methods. Microorganisms contribute to concrete degradation through physical and chemical means. In the oil and gas industry, SRB and SOB activities may adversely affect concrete in offshore platforms. MIC challenges also arise in cooling water systems and civil infrastructures, impacting concrete surfaces. Sewer systems experience biogenic corrosion, primarily driven by SRB activities, leading to concrete deterioration. Mitigation traditionally involves the use of biocides and surface coatings, but their long-term effectiveness and environmental impact are questionable. Nowadays, it is important to design more eco-friendly mitigation products. The microbial-influenced carbonate precipitation is one of the green techniques and involves incorporating beneficial bacteria with antibacterial activity into cementitious materials to prevent the growth and the formation of a community that contains species that are pathogenic or may be responsible for MIC. These innovative strategies present promising avenues for addressing MIC challenges and preserving the integrity of concrete structures. This review provides a snapshot of the MIC in various areas and mitigation measures, excluding underlying mechanisms and broader influencing factors. KW - MIC KW - Corrosion KW - Concrete KW - Environment PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-619218 DO - https://doi.org/10.3390/ma17235846 VL - 17 IS - 23 SP - 1 EP - 19 PB - MDPI AN - OPUS4-61921 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hobmeier, K. A1 - Cantone, M. A1 - Nguyen, Q. A. A1 - Pflüger-Grau, K. A1 - Kremling, A. A1 - Kunte, Hans-Jörg A1 - Pfeiffer, F. A1 - Marin-Sanguino, A. T1 - Adaptation to varying salinity in Halomonas elongata: Much more than ectoine accumulation N2 - The halophilic γ-proteobacterium Halomonas elongata DSM 2581T thrives at salt concentrations well above 10 % NaCl (1.7 M NaCl). A well-known osmoregulatory mechanism is the accumulation of the compatible solute ectoine within the cell in response to osmotic stress. While ectoine accumulation is central to osmoregulation and promotes resistance to high salinity in halophilic bacteria, ectoine has this effect only to a much lesser extent in non-halophiles. We carried out transcriptome analysis of H. elongata grown on two different carbon sources (acetate or glucose), and low (0.17 M NaCl), medium (1 M), and high salinity (2 M) to identify additional mechanisms for adaptation to high saline environments. To avoid a methodological bias, the transcripts were evaluated by applying two methods, DESeq2 and Transcripts Per Million (TPM). The differentially transcribed genes in response to the available carbon sources and salt stress were then compared to the transcriptome profile of Chromohalobacter salexigens, a closely related moderate halophilic bacterium. Transcriptome profiling supports the notion that glucose is degraded via the cytoplasmic Entner-Doudoroff pathway, whereas the Embden-Meyerhoff-Parnas pathway is employed for gluconeogenesis. The machinery of oxidative phosphorylation in H. elongata and C. salexigens differs greatly from that of non-halophilic organisms, and electron flow can occur from quinone to oxygen along four alternative routes. Two of these pathways via cytochrome bo' and cytochrome bd quinol oxidases seem to be upregulated in salt stressed cells. Among the most highly regulated genes in H. elongata and C. salexigens are those encoding chemotaxis and motility proteins, with genes for chemotaxis and flagellar assembly severely downregulated at low salt concentrations. We also compared transcripts at low and high-salt stress (low growth rate) with transcripts at optimal salt concentration and found that the majority of regulated genes were down-regulated in stressed cells, including many genes involved in carbohydrate metabolism, while ribosome synthesis was up-regulated, which is in contrast to what is known from non-halophiles at slow growth. Finally, comparing the acidity of the cytoplasmic proteomes of non-halophiles, extreme halophiles and moderate halophiles suggests adaptation to an increased cytoplasmic ion concentration of H. elongata. Taken together, these results lead us to propose a model for salt tolerance in H. elongata where ion accumulation plays a greater role in salt tolerance than previously assumed. KW - Ectoine KW - Osmoadaptation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545608 DO - https://doi.org/10.3389/fmicb.2022.846677 SN - 1664-302X VL - 13 SP - 1 EP - 19 PB - Frontiers Media CY - Lausanne AN - OPUS4-54560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nordholt, Niclas A1 - O'Hara, Kate A1 - Resch-Genger, Ute A1 - Blaskovich, M. A1 - Rühle, Bastian A1 - Schreiber, Frank T1 - A fluorescently labelled quaternary ammonium compound (NBD-DDA) to study resistance mechanisms in bacteria N2 - Quaternary ammonium compounds (QACs) are widely used as active agents in disinfectants, antiseptics, and preservatives. Despite being in use since the 1940s, there remain multiple open questions regarding their detailed mode-of-action and the mechanisms, including phenotypic heterogeneity, that can make bacteria less susceptible to QACs. To facilitate studies on resistance mechanisms towards QACs, we synthesized a fluorescent quaternary ammonium compound, namely N-dodecyl-N,N-dimethyl-[2-[(4-nitro-2,1,3-benzoxadiazol-7-yl)amino]ethyl]azanium-iodide (NBD-DDA). NBD-DDA is readily detected by flow cytometry and fluorescence microscopy with standard GFP/FITC-settings, making it suitable for molecular and single-cell studies. As a proof-of-concept, NBD-DDA was then used to investigate resistance mechanisms which can be heterogeneous among individual bacterial cells. Our results reveal that the antimicrobial activity of NBD-DDA against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa is comparable to that of benzalkonium chloride (BAC), a widely used QAC, and benzyl-dimethyl-dodecylammonium chloride (BAC12), a mono-constituent BAC with alkyl-chain length of 12 and high structural similarity to NBD-DDA. Characteristic time-kill kinetics and increased tolerance of a BAC tolerant E. coli strain against NBD-DDA suggest that the mode of action of NBD-DDA is similar to that of BAC. As revealed by confocal laser scanning microscopy (CLSM), NBD-DDA is preferentially localized to the cell envelope of E. coli, which is a primary target of BAC and other QACs. Leveraging these findings and NBD-DDA‘s fluorescent properties, we show that reduced cellular accumulation is responsible for the evolved BAC tolerance in the BAC tolerant E. coli strain and that NBD-DDA is subject to efflux mediated by TolC. Overall, NBD-DDA’s antimicrobial activity, its fluorescent properties, and its ease of detection render it a powerful tool to study resistance mechanisms of QACs in bacteria and highlight its potential to gain detailed insights into its mode-of-action. KW - Antimicrobial resistance KW - Bacteria KW - Disinfection KW - Biocides PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563811 DO - https://doi.org/10.3389/fmicb.2022.1023326 SN - 1664-302X IS - 13 SP - 1 EP - 13 PB - Frontiers Media CY - Lausanne AN - OPUS4-56381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulze-Makuch, D. A1 - Haque, S. A1 - Beckles, D. A1 - Schmitt-Kopplin, P. A1 - Harir, M. A1 - Schneider, Beate A1 - Stumpp, C. A1 - Wagner, D. T1 - A chemical and microbial characterization of selected mud volcanoes in Trinidad reveals pathogens introduced by surface water and rain water N2 - Terrestrial mud volcanoes are unique structures driven by tectonic pressure and fluids from the deep subsurface. These structures are mainly found in active tectonic zones, such as the area near the Los Bajos Fault in Trinidad. Here we report a chemical and microbiological characterization of three mud volcanoes, which included analyses of multiple liquid and solid samples from the mud volcanoes. Our study confirms previous suggestions that at least some of the mud volcano fluids are a mixture of deeper salt-rich water and surficial/precipitation water. No apparent water quality differences were found between sampling sites north and south of a major geological fault line. Microbiological analyses revealed diverse communities, both aerobic and anaerobic, including sulfate reducers, methanogens, carbon dioxide fixing and denitrifying bacteria. Several identified species were halophilic and likely derived from the deeper salt-rich subsurface water, while we also cultivated pathogenic species from the Vibrionaceae, Enterobacteriaceae, Shewanellaceae, and Clostridiaceae. These microorganisms were likely introduced into the mud volcano fluids both from surface water or shallow ground-water, and perhaps to a more minor degree by rain water. The identified pathogens are a major health concern that needs to be addressed. KW - Water stable isotope analysis KW - Mud volcanoe fluids KW - Metabolomics PY - 2020 DO - https://doi.org/10.1016/j.scitotenv.2019.136087 VL - 707 SP - 136087 PB - Elsevier B.V. AN - OPUS4-50499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tavasolyzadeh, Zeynab A1 - Tang, Peng A1 - Hahn, Marc Benjamin A1 - Hweidi, Gada A1 - Nordholt, Niclas A1 - Haag, Rainer A1 - Sturm, Heinz A1 - Topolniak, Ievgeniia T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential. KW - Direct laser writing KW - Mussel-inspired materials KW - Polyglycerol KW - Polydopamine KW - Micropatterning PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778 DO - https://doi.org/10.1002/smll.202309394 SN - 1613-6829 SP - 1 EP - 12 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -