TY - JOUR A1 - Schumacher, Julia T1 - CRISPR-Cas9 in der Materialforschung - Den gesteinsbesiedelnden Pilzen auf der Spur T1 - CRISPR-Cas9 in materials research - On the trail of rock-inhabiting fungi N2 - Das mikroskopische Leben auf exponierten Oberflächen ist genügsam und kooperativ. Gesteinsbesiedelnde schwarze Pilze, Grünalgen und Cyanobakterien unterstützen einander in der Eroberung von Felsen, Mauern, Denkmälern, Dächern, Fassaden und Sonnenkollektoren. Bedeutend sind die schwarzen Pilze als Gesteinszerstörer und Biofilmbildner. Ihre massiven Zellwände und ihr langsames Wachstum machen sie stresstolerant und fordern zugleich die experimentelle Forschung heraus. In der Materialforschung können Biofilme erwünscht oder unerwünscht sein. Biofilme auf Fassaden können das Innenstadtklima positiv beeinflussen, während sie auf einem Marmordenkmal unwillkommen sind. Ohne tieferes Verständnis der angepassten Mikroben ist weder ihre Bekämpfung noch ihre gezielte Förderung auf Materialien möglich. Hier treffen sich Genetik und Materialforschung: Die CRISPR-Cas9-Technologie ermöglicht es, die Genome der Pilze für funktionale Analysen zu editieren, um die Mechanismen der Materialbesiedlung und Materialschädigung zu entschlüsseln. N2 - Rock-inhabiting black fungi are adapted to the harsh life on rocks in deserts and release minerals from the rocks. The same adaptations enable these fungi to colonize man-made surfaces such as monuments, building facades and solar systems. Black fungi are often associated with phototrophic microorganisms. The slow growth and the melanized cell walls, which protect the fungi from extreme environmental infuences, render molecular biological and genetic engineering methods diffcult, which is why little is known about the biology of these fungi. Knufa petricola was selected to understand the processes of material colonization and damage with the help of adapted methods such as CRISPR-Cas9-mediated genome editing. KW - Knufia petricola KW - Schwarze Pilze KW - Bioflme KW - Genomeditierung KW - Pigmente KW - Multiplexing KW - Resistenzkassette KW - Transformanten KW - Knufia petricola KW - Black fungi KW - Biofilms KW - Pigments KW - Genome editing KW - Multiplexing KW - Resistance cassette KW - Transformants PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620500 DO - https://doi.org/10.11576/biuz-7595 SN - 0045-205X SN - 1521-415X N1 - Volltext (PDF) in deutsch und englisch - Full text (PDF) in German and English VL - 54 SP - 41 EP - 50 PB - Verband Biologie, Biowissenschaften und Biomedizin in Deutschland (VBiO) CY - München AN - OPUS4-62050 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - Richter, Anja A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Laser-Textured Surfaces: A Way to Control Biofilm Formation? N2 - Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria-repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria-repellent surfaces lies in the contactless and aseptic large-area laser-processing of technical surfaces. Tailored surface textures, enabled by different laser-processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state-of-the-art review of laser-surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser-processed surfaces, the challenges of anti-microbial surface designs are discussed, and future directions will be outlined. KW - Antibacterial surfaces KW - Biofilms KW - Laser processing KW - Laser-induced periodic surface structures (LIPSS) KW - Microbial adhesions PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588260 DO - https://doi.org/10.1002/lpor.202300753 SN - 1863-8899 SP - 1 EP - 41 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Song, Jessica T1 - (micro)Plastic biofilms: Keeping afloat by carving out a new niche N2 - As pervasive and persistent pollutants, microplastics exist alongside vast microbial communities in nature. These hardy substrates accumulate rich polymeric matrices from their surroundings that in turn offer nutrition and protection to diverse communities and their theatre of activity, representing a new ecological niche. In our research to date, biofilm communities demonstrate no specificity to plastic polymers but appear rather to be more strongly shaped by spatial and temporal factors. Other synthetic substrates such as tyre wear, however, signal towards some form of community selection that may manifest in the presence of leachates from the polymer itself. Contrary to these biofilms, polyaromatic hydrocarbons appear to observe the opposite pattern, with adsorbed concentrations on plastic more strongly dictated by the type of plastic polymer than the environment itself. Although community specificity has not yet been evidenced among different plastic polymers, our studies show that microplastics might shape communities in a different way. As suggested by our detection of carotenoid synthesis pathways and photosynthetic gene clusters among microplastic biofilms, we postulate this new niche to shape a specific functional toolkit adaptive among its members as a product of prolonged exposure to UV radiation at the sea’s surface. This opens exciting new avenues for further research into the functional capabilities of these biofilms and offers new perspective on their potential beyond subordinate processes such as biodegradation. Here, we present a synthesis of our collective research on microplastic biofilms, the factors that shape them, and their interactions with nature. T2 - MICRO 2024 Conference CY - Lanzarote, Spain DA - 23.09.2024 KW - Biofilms KW - Microplastics KW - Microbial ecology KW - 16S amplicon KW - Pollutants PY - 2024 AN - OPUS4-61990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Song, Jessica T1 - Close encounters on a micro scale: Dynamics and interactions of microplastic biofilms in aquatic ecosystems. N2 - Microplastics circulate freely throughout aquatic ecosystems and, due to their interactive nature, accumulate complex polymeric matrices consisting of rich organic compounds and inorganic pollutants. Simultaneously, these hardy substrates offer nutrition and protection to diverse microbial communities and their theatre of activity, representing a new ecological niche. In our work, we investigate the interactions of microplastics in aquatic systems and characterise the effects of these interactions on associated microbial communities to better understand how these substrates might impact surrounding ecosystems. Demonstrating no specificity to polymer type, microplastic biofilms are shaped more by the strong influence of spatial and temporal factors. Microplastic sorption of polycyclic aromatic hydrocarbons (PAHs), in contrast, appear to be more strongly dictated by substrate type, with different polymers observed to sorb varying levels of different PAHs. These interactions between the different emerging contaminants were found in our study to have a significant effect on associated substrate biofilms. Elevated levels of specific 3- and 4-ring PAHs on polyethylene and polystyrene were found to coincide with a notable shift in community composition and structure, as well as a reduced diversity among biofilm communities. The findings in our study illustrate the importance of investigating the collective effect of pollutants in combination and their complex interactions in assessing their environmental impact. To fully understand how microplastics interact and alter surrounding ecosystems, the entire substrate must be considered, including all chemicals integrated into the polymeric matrix. T2 - Biofilms 11 Conference CY - Cardiff, Wales, UK DA - 13.05.2025 KW - Microplastics KW - Biofilms KW - PAHs PY - 2025 AN - OPUS4-63389 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valentin, J. A1 - Straub, H. A1 - Pietsch, Franziska A1 - Lemare, M. A1 - Ahrens, C. A1 - Schreiber, Frank A1 - Webb, J. A1 - van der Mei, H. A1 - Ren, Q. T1 - Role of the flagellar hook in the structural development and antibiotic tolerance of Pseudomonas aeruginosa biofilms N2 - Pseudomonas aeruginosa biofilms exhibit an intrinsic resistance to antibiotics and constitute a considerable clinical threat. In cystic fibrosis, a common feature of biofilms formed by P. aeruginosa in the airway is the occurrence of mutants deficient in flagellar motility. This study investigates the impact of flagellum deletion on the structure and antibiotic tolerance of P. aeruginosa biofilms, and highlights a role for the flagellum in adaptation and cell survival during biofilm development. Mutations in the flagellar hook protein FlgE influence greatly P. aeruginosa biofilm structuring and antibiotic tolerance. Phenotypic analysis of the flgE knockout mutant compared to the wild type (WT) reveal increased fitness under planktonic conditions, reduced initial adhesion but enhanced formation of microcolony aggregates in a microfluidic environment, and decreased expression of genes involved in exopolysaccharide formation. Biofilm cells of the flgE knock-out mutant display enhanced tolerance towards multiple antibiotics, whereas its planktonic cells show similar resistance to the WT. Confocal microscopy of biofilms demonstrates that gentamicin does not affect the viability of cells located in the inner part of the flgE knock-out mutant biofilms due to reduced penetration. These findings suggest that deficiency in flagellar proteins like FlgE in biofilms and in cystic fibrosis infections represent phenotypic and evolutionary adaptations that alter the structure of P. aeruginosa biofilms conferring increased antibiotic tolerance. KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Biocides PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541113 DO - https://doi.org/10.1038/s41396-021-01157-9 SN - 1751-7370 VL - 16 IS - 4 SP - 1176 EP - 1186 PB - Springer Nature AN - OPUS4-54111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valentin, Jules D. P. A1 - Altenried, Stefanie A1 - Varadarajan, Adithi R. A1 - Ahrens, Christian H. A1 - Schreiber, Frank A1 - Webb, Jeremy S. A1 - van der Mei, Henny C. A1 - Ren, Qun T1 - Identification of Potential Antimicrobial Targets of Pseudomonas aeruginosa Biofilms through a Novel Screening Approach N2 - Pseudomonas aeruginosa is an opportunistic pathogen of considerable medical importance, owing to its pronounced antibiotic tolerance and association with cystic fibrosis and other life-threatening diseases. The aim of this study was to highlight the genes responsible for P. aeruginosa biofilm tolerance to antibiotics and thereby identify potential new targets for the development of drugs against biofilm-related infections. By developing a novel screening approach and utilizing a public P. aeruginosa transposon insertion library, several biofilm-relevant genes were identified. The Pf phage gene (PA0720) and flagellin gene (fliC) conferred biofilm-specific tolerance to gentamicin. Compared with the reference biofilms, the biofilms formed by PA0720 and fliC mutants were completely eliminated with a 4-fold-lower gentamicin concentration. Furthermore, the mreC, pprB, coxC, and PA3785 genes were demonstrated to play major roles in enhancing biofilm tolerance to gentamicin. The analysis of biofilm-relevant genes performed in this study provides important novel insights into the understanding of P. aeruginosa antibiotic tolerance, which will facilitate the detection of antibiotic resistance and the development of antibiofilm strategies against P. aeruginosa. KW - Antimicrobial resistance KW - Bacteria KW - Biofilms KW - Pseudomonas aeruginosa PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570205 DO - https://doi.org/10.1128/spectrum.03099-22 SP - 1 EP - 5 PB - ASM Journals AN - OPUS4-57020 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 - 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 -