4 Material und Umwelt
Filtern
Dokumenttyp
- Vortrag (91)
- Posterpräsentation (62)
- Zeitschriftenartikel (16)
- Beitrag zu einem Tagungsband (11)
- Buchkapitel (3)
- Forschungsbericht (3)
- Dissertation (2)
- Sonstiges (2)
- Beitrag zu einem Sammelband (1)
- Video (1)
Sprache
- Englisch (160)
- Deutsch (30)
- Chinesisch (2)
Referierte Publikation
- nein (192) (entfernen)
Schlagworte
- Biocides (38)
- Antimicrobial resistance (28)
- MIC (21)
- Corrosion (19)
- Biofilms (18)
- Bacteria (16)
- Methanogens (13)
- Evolution (12)
- Microbiologically influenced corrosion (11)
- E. coli (10)
- Antimicrobial coating (9)
- Biocide (9)
- Resistance (9)
- Archaea (8)
- Disinfection (8)
- Microbiology (8)
- NAP-XPS (8)
- Persistence (8)
- Standardization (8)
- Biofilm (7)
- Horizontal gene transfer HGT (7)
- Resistance evolution (7)
- Korrosion (6)
- Tolerance (6)
- Alginate (5)
- Antibiotics (5)
- Biocide tolerance (5)
- Environmental Simulation (5)
- Heterogeneity (5)
- Laser-induced periodic surface structures (LIPSS) (5)
- Risk assessment (5)
- Single cell analysis (5)
- Termites (5)
- Umweltsimulation (5)
- Bacterial adhesion (4)
- Corrosion products (4)
- Cross-resistance (4)
- Glutaraldehyde (4)
- Hi-Tension (4)
- Holzschutz (4)
- Horizontal gene transfer (4)
- Kulturgut (4)
- Mutation rate (4)
- Sc-ICP-ToF-MS (4)
- Anobium punctatum (3)
- Anoxia (3)
- Antimicrobial surfaces (3)
- Antimicrobials (3)
- Antimikrobielle Resistenz (3)
- Antmikrobielle Oberflächen (3)
- Biofilm formation (3)
- Biozide (3)
- Carbon steel (3)
- DIN (3)
- Ectoine (3)
- Environmental simulation (3)
- FIB/SEM (3)
- Flow Model (3)
- LIPSS (3)
- Methanogen (3)
- Methanogen-induced microbiologically influenced corrosion (3)
- Mikrobiell beeinflusste Korrosion (3)
- Modelling (3)
- Normung (3)
- Phenotypic diversity (3)
- SC-ICP-ToF-MS (3)
- Standardisierung (3)
- Sulfate reducing bacteria (3)
- Termite (3)
- Wastewater (3)
- Wood protection (3)
- XPS (3)
- Antibiotic resisitance (2)
- Antimicrobial (2)
- Apanteles carpatus (2)
- Bacterial adhesion tests (2)
- Baryscapus tineivorus (2)
- Biocorrosion (2)
- Biodiversity (2)
- Biofilm growth (2)
- Biotechnology (2)
- CEN (2)
- Carbon steel corrosion (2)
- Corrosion evolution (2)
- Corynetes caeruleus (2)
- Desinfectant (2)
- Disinfectants (2)
- Disposal repository (2)
- E.coli (2)
- Environmental condition (2)
- HAXPES (2)
- HI-Tension (2)
- Halomonas CRISPR Ectoine (2)
- IPM (2)
- ISO (2)
- Immunity (2)
- Ir DNA staining approach (2)
- Iron (2)
- LA-ICP-MS (2)
- Metabolism (2)
- Method development (2)
- Microbiological influenced corrosion MIC (2)
- Microorganism (2)
- Mikroorganismen (2)
- Modelling studies (2)
- NanoSIMS (2)
- Nanoparticles (2)
- Nitrogen (2)
- Nuclear waste (2)
- Optics (2)
- Persister cells (2)
- Pollutants (2)
- Risk assesment (2)
- Schadstoffaustrag (2)
- Schimmel (2)
- Single cell (2)
- Tineola bisselliella (2)
- 2D nanomaterials (1)
- AMR (1)
- Academia (1)
- Acidobacteria (1)
- Agarose (1)
- Analytical standards (1)
- Anpassung (1)
- Antagonism (1)
- Anti-microbial effects (1)
- Antiadhesive surfaces (1)
- Antibakterielle Oberflächen (1)
- Antibiotic (1)
- Antimicrobial Resistance (1)
- Aspergillus flavus (1)
- Atomic force microscopy (1)
- Auslaugtests (1)
- Bacteria repellent surfaces (1)
- Bacteria-repellent surfaces (1)
- Bacterial attachment (1)
- Bacterial growth (1)
- Bakterien (1)
- Bankia sp (1)
- Bauprodukte (1)
- Bestandserhaltung (1)
- Bewitterung (1)
- Biofilme (1)
- Bioilm (1)
- Bioinformatics (1)
- Biokorrosion (1)
- Biological Control (1)
- Biological control (1)
- Biological pest control (1)
- Biologische Bekämpfung (1)
- Biotische/abiotische Faktoren (1)
- Blauer Engel (1)
- Brown-rot fungi (1)
- COST (1)
- COST Action (1)
- CRISPR dCas9 (1)
- Calcareous deposits (1)
- Cast iron (1)
- Cathodic protection (1)
- Compatible solute (1)
- Conditioning layer (1)
- Coniophora puteana (1)
- Construction Products (1)
- Contamination (1)
- Controlled atmosphere (1)
- Coptotermes (1)
- Core microbiome (1)
- Corrosion environment (1)
- Corrosion product (1)
- Cribellate spiders (1)
- Cultural Heritage (1)
- Cultural heritage (1)
- DIN EN 350 (1)
- DNA barcode (1)
- Dauerhaftigkeit (1)
- Deterioration (1)
- Durability (1)
- E$volution (1)
- Ecology (1)
- Efflux (1)
- Entwicklung (1)
- Essential oils (1)
- Europa (1)
- Experimental evolution (1)
- Femtosecond laser processing (1)
- Flammschutzmittel (1)
- Flow chamber system (1)
- Flow system (1)
- Flow-System (1)
- Flow-system (1)
- Fluorescence (1)
- Fluoride nanoparticles (1)
- Fluorides (1)
- Fluorolytic sol−gel (1)
- Flügel (1)
- Food safety (1)
- Force distance curve (1)
- Functionalized graphene (1)
- Fungi (1)
- Fungicidal property (1)
- Fungus (1)
- Gas storage (1)
- Gebindekonservierung (1)
- Geological formation (1)
- Gesteinskorrosion (1)
- Gütezeichen (1)
- H2-Abbau (1)
- Halomonas elongata (1)
- Halophile (1)
- Halophilic (1)
- Hausbock (1)
- Hausbockkäfer (1)
- Herteogeneous phenotypes (1)
- High salinity (1)
- Holzschutz, (1)
- Holzschutzmittel (1)
- Hydrogen (1)
- Hydrogen permeation (1)
- Hydrogenasen (1)
- Hydrophobic interaction (1)
- Hylotrupes bajulus (1)
- Hylotrupes bajulus, Anobium punctatum, natural durability, tropical wood, native wood. (1)
- IPM in museums (1)
- ISO22196 (1)
- Implants (1)
- In situ (1)
- Industrial applications (1)
- Initial attachment (1)
- Interdisciplinary (1)
- Iodine (1)
- Ionizing radiation (1)
- Isothiazolinone (1)
- Kleidermotte (1)
- Kontamination von H2 (1)
- Korynetes caeruleus (1)
- Kraftstoffabbau (1)
- Kraftstoffbehälter (1)
- Kulturelle Entomologie (1)
- Lake Cadagno (1)
- Laser processing (1)
- Laser structuring (1)
- Laser-Materialbearbeitung (1)
- Laser-induced pariodic surface structures (1)
- Laser-induced periodic surface structueres (LIPPS) (1)
- Leaching (1)
- Library pests (1)
- Life history data (1)
- Lightning talk (1)
- Limnoria spp (1)
- Low alloy steel (1)
- MDG ICP-ToF-MS (1)
- MIC Island (1)
- MIC projekt (1)
- Marine borers (1)
- Material degradation (1)
- Materials (1)
- Metal organic frameworks (1)
- Metal reducing bacteria (1)
- Metallkorrosion (1)
- Metalls (1)
- Methanogene (1)
- Methanogenesis (1)
- Methode (1)
- Microbial (1)
- Microbial community modelling (1)
- Microbially Induced Corrosion (1)
- Microbiologically Influrenced Corrosion (MIC) (1)
- Microbiologically influenced corrosion (MIC) (1)
- Microdroplet generator (1)
- Microfluidics (1)
- Migration (1)
- Mikrobielle Gemeinschaft (1)
- Mircobially influcenced corrosion (1)
- Model (1)
- Molecular (1)
- Museum (1)
- Museum Pests (1)
- Museum insect pest (1)
- Museum pests (1)
- Museumsschädling (1)
- Museumsschädlinge (1)
- Mycotoxins (1)
- Nano characterization (1)
- Nano metal fluorides (1)
- Nanorods (1)
- Natural products discovery (1)
- Near ambient pressure XPS (1)
- Neozoon (1)
- Netzwerk (1)
- Norm (1)
- Nuclear waste disposal (1)
- Oberflächenfunktionalisierung (1)
- Oil and gas reservoir (1)
- Oilfield (1)
- Osmophobic effect (1)
- PBFSM (1)
- PE-HD (1)
- Paper sizings (1)
- Persian historical recipes (1)
- Persian manuscripts (1)
- Physical and optical characteristics (1)
- Pilz (1)
- Polymer foils (1)
- Polypropylen (1)
- Polystyrol (1)
- Poster presentation (1)
- Preferential binding (1)
- Preferential exclusion (1)
- Projekte (1)
- Pseudomonas (1)
- RFA (1)
- Reactive oxygen species (1)
- Religion (1)
- Rhodonia placenta (1)
- Risikobewertung (1)
- Round robin test (1)
- SEM wood characterization (1)
- SEM-EDS (1)
- SRB (1)
- Schmetterlinge (1)
- Selection (1)
- Shale (1)
- Simulation (1)
- Sizing (1)
- Social (1)
- Social immunity (1)
- Social insects (1)
- Solubility (1)
- Spectral imaging (1)
- Stainless steel (1)
- Stakeholder (1)
- Standardized test and quantification procedure (1)
- Structural color (1)
- Superhydrophilic surface (1)
- Superhydrophobic surface (1)
- Surface functionalization (1)
- Synchrotron-XPS (1)
- Temperature and humidity (1)
- Teredo sp (1)
- Termite control (1)
- Termite-associated microbes (1)
- Termiten (1)
- Textilschädling (1)
- ToF SIMS (1)
- ToF-SIMS (1)
- Trait-based ecology (1)
- UV-irradiation (1)
- Ultrakurzpuls-Laser (1)
- Ultrashort laser processing (1)
- Unterirdische Speicher (1)
- Velocimetry (1)
- Vererbung (1)
- Wasserstofflagerung (1)
- Wirksamkeit (1)
- X-ray spectroscopic techniques (1)
- XANES (1)
- XRF (1)
- Xestobium rufovillosum (1)
- biocide tolerance (1)
- disinfection (1)
- evolution (1)
- fs-laser processing (1)
- heterogeneity (1)
- underexplored phyla (1)
Organisationseinheit der BAM
- 4.1 Biologische Materialschädigung und Referenzorganismen (192) (entfernen)
Eingeladener Vortrag
- nein (91)
Questions:
Biocides are in contact with soils through direct application and passive leaching from protected materials. Consequently, soil microorganisms are exposed to toxic biocides even though they are not their primary targets. Soil is a large reservoir of microbial diversity and has been hypothesized to be a crucial factor for the evolution and spread of antimicrobial resistance. Currently, there is little knowledge on how biocides used to protect materials affect the evolution and spread of resistance. Thus, our aim is to investigate the risk for the evolution of biocide resistance and cross-resistance to antibiotics. In addition, we aim to elucidate the affect of biocides on the spread of resistance via horizontal gene transfer (HGT).
Methods:
In laboratory evolution experiments we culture selected model soil microorganism with representative biocides followed by antibiotic cross-resistance determination and genome sequencing. Moreover, we investigate if the selected biocides affect the HGT frequency of plasmids that carry resistance genes among soil microorganism and the consequences for survival of the affected populations.
Results:
Our initial results show only small increases of biocide resistance during serial transfers in the presence of biocides. One reason for this might be the narrow selective window for biocide resistance due to steep dose-response relationships. Furthermore, we will present results from ongoing experiments on the effects of material preservatives on HGT frequencies facilitating microbial community adaptation to stress.
Conclusions:
The results will enable future risk assessment regarding resistance evolution for biocides used as material preservatives.
An understanding of the interactions of 2D nanomaterials with pathogens is of vital importance to developing and controlling their antimicrobial properties. In this work, the interaction of functionalized graphene with tunable hydrophobicity and bacteria is investigated. Poly-(ethylene glycol)-block-(poly-N-isopropylacrylamide) copolymer (PEG-b-PNIPAM) with the triazine joint point was attached to the graphene Surface by a nitrene [2 + 1] cycloaddition reaction. By thermally switching between hydrophobic and hydrophilic states, functionalized graphene sheets were able to bind to bacteria. Bacteria were eventually disrupted when the functionality was switched to the hydrophobic state. On the basis of measuring the different microscopy methods and a live/dead viability assay, it was found that Escherichia coli (E. coli) bacteria are more susceptible to hydrophobic interactions than B. cereus bacteria, under the same conditions. Our investigations confirm that hydrophobic interaction is one of the main driving forces at the presented graphene/bacteria interfaces and promotes the antibacterial activity of graphene derivatives significantly.
Bacterial samples are typically freeze dried or cryo-prepared prior to XPS analysis to allow for measurements in ultra-high vacuum (UHV). The sample environment in the near-ambient pressure (NAP) XPS instrument EnviroESCA allows for measurements in up to 15 mbar water vapor, thus, sample preparation is no longer restricted to UHV-compatible techniques. For instance, biofilms grown in medium can be transferred directly from the medium to the measurements chamber, maintaining a humid environment throughout the measurements. Considering the complexity of bacterial samples, sample preparation must be carefully considered in order to obtain meaningful and reproducible results.
In this talk, various strategies for sample preparation of bacteria and biofilms for NAP-XPS measurements will be discussed. Model systems of planktonic bacteria, artificial biofilms resembling the exopolysaccharide matrix and biofilms have been characterised in various conditions. The stability and homogeneity of the samples was assessed by monitoring the C1s core level peak at different sample locations. The quality of the XPS-spectra is also influenced by the gas environment, which will be exemplified by core level spectra of P. Fluorescens acquired in air, water vapor and ultra-high vacuum.
Introduction: Biofilms are regarded as a common cause of chronic infections on medical devices. Preventive and therapeutic strategies against biofilm infections commonly involve applications of multiple antimicrobial substances: antimicrobial coatings on the implanted biomaterials in combination with systemically administered antibiotics. While this practice of combination therapy harbours the risk of developing cross-resistance, it might also provide the possibility to implement specific antimicrobial-antibiotic combinations (AACs) that can slow down the selection of antibiotic resistant strains.
Hypothesis and aims: Specific AACs can exert combinatorial effects on the growth of susceptible and antibiotic-resistant Pseudomonas aeruginosa that either suppress or increase their individual effects.
Our aim is to identify AACs with antagonistic or synergistic effects on pseudomonal biofilms and to understand their impact on selection of resistant strains. Specifically, we want to identify AACs that select for and against antibiotic resistance during biofilm formation.
Methodology: We screened for AACs that cause antagonistic or synergistic effects on planktonic P. aeruginosa.
To study the effect of antimicrobial-antibiotic exposure on resistance selection in bacterial biofilms, we will grow resistant and sensitive strains on PDMS surfaces with and without antimicrobial coatings and expose them to antibiotics.
Results: Several combinations with synergistic or antagonistic interaction on the growth rate of P. aeruginosa were detected. We observed a strong antagonism when combining the antimicrobial substance chlorhexidine with the carbapenem drug meropenem. A meropenem-resistant mutant showed a selection advantage in low concentrations of chlorhexidine combined with a sub-inhibitory concentration of meropenem over the wild-type. No antagonistic effect was observed for the same combination when E. coli was exposed to chlorhexidine and meropenem, suggesting a non-chemical basis for the observed effect on P. aeruginosa.
Conclusion: Gaining a better understanding about resistance selection during biofilm formation on biomedical surfaces will enable us to mitigate against biofilm-associated antimicrobial resistance.
Question:
One cornerstone to prevent the spread of bacteria in clinical and industrial settings is the application of biocides including disinfectants and preservatives. However, bacteria can evolve resistance to biocides, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population. Our objective is to investigate if persistence is a bacterial survival strategy against biocides. Furthermore, we investigate the mechanisms of biocide persistence and if persistence can evolve in the face of fluctuating exposure to biocides. Lastly, we test if the evolved mechanisms of biocide tolerance lead to biocide resistance and if they confer cross-tolerance and cross-resistance against antibiotics.
Methods:
We use time-kill assays in the presence of biocides and experimental evolution combined to whole-genome sequencing in the model organism E. coli.
Results:
We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against biocides. In addition, we will present data from an ongoing evolution experiment for persistence against biocides.
Conclusion
There is a link between antibiotic and biocide persistence with possible implications for antibiotic resistance evolution and spread.
Background:
One cornerstone to prevent the spread of antibiotic resistant bacteria in clinical settings is the application of disinfectants. However, bacteria can evolve resistance to disinfectants, which in turn can confer cross-resistance to antibiotics. Additionally, clonal bacterial populations can display phenotypic heterogeneity with respect to the tolerance of antibiotic stress leading to a prolonged survival of a sub-population; this phenomenon is termed persistence. Persistence to antibiotics is an evolvable trait and can serve as a stepping stone for the evolution of genetically encoded resistance. Until now, there is a lack of systematic studies that investigate if bacterial populations establish persister subpopulations that tolerate disinfectant stress longer than most of the population.
Objectives:
Our objective is to investigate if persistence is a bacterial survival strategy against disinfectants. Furthermore, we investigate the mechanisms of disinfectant persistence and if persistence can evolve in the face of fluctuating exposure to disinfectants. Lastly, we test if the evolved mechanisms of disinfectant tolerance lead to disinfectant resistance and if they confer cross-tolerance and cross-resistance against antibiotics.
Methods:
We use time-kill assays in the presence of disinfectants and experimental evolution combined to whole-genome sequencing in the model organism E. coli.
Results:
We find persister sub-populations against chlorhexidine and quaternary ammonium compounds, but not to alcohols, aldehydes and oxidative compounds. We will present the relationship of mechanisms known to underlie antibiotic persister formation to the formation of persisters against disinfectants. In addition, we will present data from an ongoing evolution experiment for persistence against disinfectants.
A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning.
A fundamental question in ecology is how biodiversity affects ecosystem function. Biodiversity is commonly estimated based on genetic variation. We investigated a new approach that defines and measures biodiversity in complex microbial communities. We used the variation in multiple functionally-relevant, phenotypic traits measured in parallel in single cells as a metric for microbial phenotypic diversity. We studied phenotypic diversity and ecosystem functioning throughout different photosynthetic layers dominated by divergent microbial communities in the gradient of Lago di Cadagno. We determined genetic diversity by 16S and 18S amplicon sequencing and bulk ecosystem functioning (photosynthesis). In addition, we determined phenotypic diversity using single-cell technologies such as nanometer-scale secondary ion mass spectrometry (NanoSIMS) correlated with confocal laser scanning microscopy (CLSM) and scanning flow-cytometry. We measured functional trait variation between individuals in 13CO2 fixation, 15NH4+ uptake, and variation in physio-morphological cell traits, such as cell size, shape, and auto-fluorescence for various pigments related to photosynthesis. We used the distances between individuals in a multidimensional trait space to derive phenotypic trait-based diversity indices, such as trait richness, trait evenness, and trait divergence. We find that phenotypic trait divergence associates with ecosystem functioning, whereas genetic diversity does not. Including activity-based, single-cell phenotypic measurements with NanoSIMS provided an additional accuracy to the trait-based diversity assessment and allowed us to formulate hypotheses on the mechanisms that shape the correlation between phenotypic diversity and eco-system function. Together, our results show that phenotypic diversity is a meaningful concept to measure microbial biodiversity and associate it with ecosystem functioning.
Uninvited and Welcomed Guests in Museums – Biological management of
clothes moths and woodworms
(2019)
In museums and historic houses clothes, moths (Tineola bisselliella, Tinea pellionella) and the furniture beetle (Anobium punctatum) are the most economically important pests on textiles or wooden artifacts, respectively. Their management is essential to protect cultural ethnological heritage and natural history collections for future generations.
Pest management strategies have changed over time. Today, intensive knowledge on pest biology and overall material science are key cornerstones in IPM concepts - also for the museum environment. The important first steps for sustainable pest management are risk assessment, early pest detection and identification of pathways of infestation. These steps are followed by physical and biological means of control, which have lately gained more importance than applying biocides.
Several potentially effective biological enemies of clothes moths and woodworm have been known for a long time, but their promotion for pest control in museums and historic houses is just beginning.
This short review summarizes current concepts of pest life cycle interruption by applying good quarantine and very specific biological measures. The lessons learned from recent faunistic surveys, life-history studies as well as behavioral observations of parasitoids and predators of clothes moths and woodworm may supplement the pest management tool box. The need for further research in this field is addressed.
The compatible solute ectoine is a versatile protectant synthesized by many prokaryotes. It is used as an osmolyte helping microorganisms to maintain an osmotic equilibrium. In addition, ectoine acts as a stabilizer and protects proteins, membranes and whole cells against detrimental effects such as freezing and thawing, drying and high temperatures. Its protective effect is explained by the preferential exclusion model, which postulates that ectoine does not directly interact with biomolecules but is excluded from their surface. Interestingly, details on the interaction of ectoine with DNA are still unknown. Therefore, we studied the influence of ectoine on DNA and the mechanisms by which ectoine protects DNA against ionizing radiation. To emulate biological conditions, we used a sample holder comprising a silicon chip with a Si3N4 membrane, which allows for electron irradiation of DNA in aqueous solution. Analysis by atomic force microscopy revealed that without ectoine, DNA was damaged by irradiation with a dose of 1,7 +/-0,3 Gy. With ectoine, DNA remained undamaged, even after irradiation with 15 Gy. Simulations with dsDNA and ectoine in water revealed a preferential binding of the zwitterionic ectoine to the negatively charged DNA. According to the simulations, binding of ectoine will destabilize dsDNA. Destabilizing is probably caused by the transition of B-DNA to A-DNA and will reduce the DNA melting temperature, which was experimentally proven. The preferential binding provides a stable ectoine shell around DNA, which allows ectoine to reduce OH-radicals and electrons near the DNA and thereby mitigating the damaging effect of ionizing radiation.
The global rise of antibiotic resistance has made the proper use of disinfectants more important than ever. Their application in clinical l settings is an integral part of antibiotics stewardship by preventing the occurrence and spread of infections. However, improper use of disinfectants also harbours the risk for the evolution of tolerance and resistance to disinfectants, but also to antibiotics. It is therefore crucial to understand whether and how bacteria can survive chemical disinfection and which conditions facilitate the evolution of tolerance and resistance.
Here, we study the heterogeneity in the response of isogenic E. coli populations exposed to different levels of commonly used disinfectants. At concentrations below the minimal inhibitory concentration (MIC), we find that certain disinfectants induce prolonged lag times in individual cells, a phenotype that has been associated with persistence against antibiotics. At concentrations above the MIC, we find heterogeneous killing for a range of the tested substances. Interestingly, for the three cationic surfactants that were tested, we find kill kinetics revealing the presence of a tolerant subpopulation that can withstand disinfection longer than most of the population. We will present results from an ongoing evolution experiment in which we test the potential for evolution of population-wide tolerance and resistance through intermittent exposure to lethal doses of a cationic surfactant.
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in oil and gas facilities. SRM act upon the metal by the re-activeness of hydrogen sulfide (HS-), and by withdrawal of the available electrons in electrical contact with the metal (EMIC). Methanogenic archaea (MA) can also cause MIC (Mi-MIC). Several MAs were identified to be corrosive by using elemental iron as the sole electron donor for methanogenesis, including Methanobacterium-affliated IM1 and Methanococcus maripaludis Mic1c10. Currently, low corrosion rates were reported for MA, possibly due to the formation of siderite (4Fe + 5HCO3- + 5H+ ® 4FeCO3 + CH4 + 3H2O). Since MA do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of MA, we studied the EMIC methanogenic strains (IM1 and Mic1c10) individually or part of a syntrophic co-culture with SRM. Corrosion studies were conducted using an in-house developed flow-through system to simulate fluctuating environmental conditions. Results indicate that the rates of iron corrosion by MA (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr) and the co-culture (0.1 mm/yr). Scanning electron microscopy (SEM) images of the metal incubated with MA showed severe pitting corrosion. Genomic analysis of the EMIC MA was conducted to provide an insight on the possible cellular mechanisms that could be involved. Furthermore, low concentrations of MA-targeting biocides will be applied to EMIC MA in static and flow conditions to gain insights for possible mitigation strategies. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.
Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea can also cause MIC by directly withdrawing electrons from the iron surface for methanogenesis. However, the mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite, a by-product of methanogenesis, (4Fe + 5HCO3 + 5H+ 4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes.
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.zeige weniger
Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood.
To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC.
Since the early 19th century microorganisms were studied on their capabilities of causing microbiologically influenced corrosion (MIC) of metals. The most studied ones are sulfate-reducing bacteria (SRB), but others can corrode metals as well, e.g. acid-producing bacteria or methanogenic archaea (MA). However, these studies were mostly focused on metals related to the petroleum industry but metals for other industries, e.g. dentistry, are also susceptible to corrosion. The inert Titanium (Ti) is often used as an implant material, but it is a base metal. The formation of a passivating oxide layer allows Ti to be corrosion resistant at normal conditions.
Nonetheless, scanning electron microscope images on dental implants from patients with acute peri-implantitis showed clear signs of corrosion. Currently, the corrosion mechanism of dental implants is unknown, but many indications suggest that oral microorganisms, including MA (Methanobrevibacter oralis) and SRB (Desulfomicrobium orale), could be involved.
To determine if MA or SRB can corrode Ti (pure Ti or Ti-6Al-4V alloy), corrosion rate, methane and sulfide concentrations were analyzed. Electrical potential measurements using in-house developed electrochemical cells indicated a potential change on Ti in the presence of a corrosive MA strain compared to an abiotic control.
Microbial composition comparison will be analyzed using samples from dental pockets of 150 infected patients by considering the quality of the implant and 50 healthy people by means of amplicon sequencing. Enrichments and isolation of pure cultures from the dentals samples are also examined for their corrosion behavior. Overall, this is the first study investigating the susceptibility of dental implant material to corrosion using human related MA.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea can also cause MIC by directly withdrawing electrons from the iron surface for methanogenesis. However, the mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite, a by-product of methanogenesis, (4Fe + 5HCO3 + 5H+ 4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes.
Normativ ist der Holzschutz in Deutschland durch die DIN 68800-Reihe geregelt. Die Normungsarbeit in CEN/TC 38 bildet dafür den Rahmen, der national angepasst und fachspezifisch erweitert wurde. Zusammen mit dem Kommentar ergeben beide ein in Europa einzigartiges Regelkompendium im Holzschutz. In Zukunft wird die Regelsetzung noch stärker durch internationale Zusammenarbeit bestimmt sein. Der interkontinentalen Marktöffnung sollten Verständigungen auf gemeinsame Qualitätsstandards vorausgehen.