4 Material und Umwelt
Filtern
Dokumenttyp
- Zeitschriftenartikel (84)
- Vortrag (73)
- Posterpräsentation (62)
- Beitrag zu einem Tagungsband (9)
- Buchkapitel (2)
- Dissertation (2)
- Sonstiges (2)
- Forschungsbericht (2)
- Beitrag zu einem Sammelband (1)
- Video (1)
Sprache
- Englisch (238) (entfernen)
Schlagworte
- Biocides (44)
- Antimicrobial resistance (34)
- Bacteria (22)
- Biofilms (22)
- Corrosion (20)
- MIC (18)
- Evolution (13)
- Methanogens (13)
- Microbiologically influenced corrosion (13)
- Biofilm (12)
- Disinfection (11)
- E. coli (11)
- NAP-XPS (11)
- Antimicrobial coating (10)
- Biocide (9)
- Persistence (9)
- Resistance (9)
- Archaea (8)
- Ectoine (8)
- Microbiology (8)
- Standardization (8)
- Horizontal gene transfer HGT (7)
- Laser-induced periodic surface structures (LIPSS) (7)
- Resistance evolution (7)
- Antibiotics (6)
- Bacterial adhesion (6)
- Biocide tolerance (6)
- Horizontal gene transfer (6)
- Termites (6)
- Tolerance (6)
- Wood protection (6)
- Alginate (5)
- Cross-resistance (5)
- Environmental Simulation (5)
- Heterogeneity (5)
- Korrosion (5)
- Methanogen (5)
- Mutation rate (5)
- Risk assessment (5)
- Sc-ICP-ToF-MS (5)
- Single cell analysis (5)
- XPS (5)
- Anobium punctatum (4)
- Antimicrobials (4)
- Biocorrosion (4)
- Biofilm formation (4)
- Carbon steel (4)
- Corrosion products (4)
- Glutaraldehyde (4)
- Method development (4)
- NanoSIMS (4)
- Polyethylene (4)
- Tineola bisselliella (4)
- Antimicrobial (3)
- Antimicrobial surfaces (3)
- Carbon steel corrosion (3)
- Environmental simulation (3)
- FIB/SEM (3)
- Flow Model (3)
- Halomonas elongata (3)
- Immunity (3)
- Ir DNA staining approach (3)
- LIPSS (3)
- Laser processing (3)
- Metabolism (3)
- Methanogen-induced microbiologically influenced corrosion (3)
- Microbiological influenced corrosion MIC (3)
- Modelling (3)
- Modelling studies (3)
- Nanoparticles (3)
- Osmoadaptation (3)
- Phenotypic diversity (3)
- SC-ICP-ToF-MS (3)
- Single cell (3)
- Sulfate reducing bacteria (3)
- Termite (3)
- Wastewater (3)
- Wood Protection (3)
- Anoxia (2)
- Antagonism (2)
- Antibiotic resisitance (2)
- Apanteles carpatus (2)
- Bacterial adhesion tests (2)
- Bacterial attachment (2)
- Baryscapus tineivorus (2)
- Biodiversity (2)
- Biofilm growth (2)
- Bioinformatics (2)
- Biological pest control (2)
- Biotechnology (2)
- Brown-rot fungi (2)
- Compatible solute (2)
- Condensed Matter Physics (2)
- Corynetes caeruleus (2)
- Cultural heritage (2)
- DNA (2)
- Degradation (2)
- Desinfectant (2)
- Disinfectants (2)
- E.coli (2)
- Energy Engineering and Power Technology (2)
- Environmental condition (2)
- Flow system (2)
- Fuel Technology (2)
- HAXPES (2)
- Halomonas CRISPR Ectoine (2)
- Halophile (2)
- Hi-Tension (2)
- Insect biotechnology (2)
- Iron (2)
- Isoptera (2)
- Keratin (2)
- Korynetes caeruleus (2)
- Leaching (2)
- Life history data (2)
- Microbiologically influenced corrosion (MIC) (2)
- Microorganism (2)
- Mikrobiell beeinflusste Korrosion (2)
- Model (2)
- Nitrogen (2)
- Nosema ceranae (2)
- Optics (2)
- Osmia bicornis (2)
- Persister cells (2)
- Pollutants (2)
- Pseudomonas aeruginosa (2)
- Reactive oxygen species (2)
- Renewable Energy, Sustainability and the Environment (2)
- Risk assesment (2)
- Shale (2)
- Social (2)
- UV-irradiation (2)
- Wild bees (2)
- 2D nanomaterials (1)
- 3D printing (1)
- A-DNA conformation (1)
- AMR (1)
- Academia (1)
- Acidobacteria (1)
- Agarose (1)
- Alkylating agents (1)
- Amphiphilic polymer (1)
- Anaerobic pathways (1)
- Analytical standards (1)
- Anti-microbial effects (1)
- Antiadhesive surfaces (1)
- Antibacterial (1)
- Antibacterial polymer (1)
- Antibacterial surfaces (1)
- Antibiotic (1)
- Antibiotic resistance (1)
- Antifouling (1)
- Antimicrobial Resistance (1)
- Antimicrobial test (1)
- Antiseptic agents (1)
- Artificial weathering (1)
- Aspergillus (1)
- Aspergillus flavus (1)
- Atomic and Molecular Physics and Optics (1)
- Atomic force microscopy (1)
- Automated analysis (1)
- BODIPY (1)
- Bacillus subtilis (1)
- Bacteria repellent surfaces (1)
- Bacteria-repellent surfaces (1)
- Bacterial cell cycle (1)
- Bacterial growth (1)
- Bacterial second messenger (1)
- Bankia sp (1)
- Basidiomycetes (1)
- Bee diseases (1)
- Bee health (1)
- Beneficial microbes (1)
- Biodeterioration (1)
- Biodeterioration and biodegradation (1)
- Biofilm quantification (1)
- Biofouling (1)
- Bioilm (1)
- Bioinformatics virology viruses software (1)
- Biokorrosion (1)
- Biological Control (1)
- Biological control (1)
- Biomimetic (1)
- Biosynthesis (1)
- Biphasic growth (1)
- C-di-GMP (1)
- COST Action (1)
- COST action CA15114 AMICI (1)
- CRISPR dCas9 (1)
- Calcareous deposits (1)
- Cast iron (1)
- Cathodic protection (1)
- Cell appendages (1)
- Cell studies (1)
- Cell-envelope (1)
- Cellulose synthase (1)
- Chemicals (1)
- Cleridae (1)
- Coleoptera (1)
- Conditioning layer (1)
- Coniophora puteana (1)
- Conjugate (1)
- Conjugation (1)
- Contamination (1)
- Controlled atmosphere (1)
- Coptotermes (1)
- Core microbiome (1)
- Corrosion product (1)
- Cribellate spiders (1)
- Cross-feeding (1)
- Cryo XPS (1)
- CuNPs (1)
- Cultural Heritage (1)
- Cupriavidus campinensis (1)
- DNA barcode (1)
- DSM 5009 (1)
- Decomposition point (1)
- Degradable polymer (1)
- Denitrification (1)
- Desert ecology (1)
- Deterioration (1)
- Dielectric heating (1)
- Dietary adaptation (1)
- Diffractive gratings (1)
- Direct laser writing (1)
- Disinfection Fuel (1)
- Disposal (1)
- Diversity (1)
- Drywood termite (1)
- Durability (1)
- Dye (1)
- E$volution (1)
- Ecology (1)
- Efficacy (1)
- Efflux (1)
- Electronic (1)
- Environment (1)
- Environmental conditions (1)
- Environmental simulations (1)
- Essential oils (1)
- Exocrine gland (1)
- Experimental evolution (1)
- External (1)
- Extremophile (1)
- F pili (1)
- Femtosecond laser processing (1)
- Fenton-like reaction (1)
- Flow chamber system (1)
- Flow-System (1)
- Flow-system (1)
- Fluorescence (1)
- Fluorescence spectroscopy (1)
- Fluoride (1)
- Fluoride nanoparticles (1)
- Fluorides (1)
- Fluorolytic sol-gel synthesis (1)
- Fluorolytic sol−gel (1)
- Food fermentation (1)
- Food safety (1)
- Force distance curve (1)
- Fuel sorption (1)
- Functionalized graphene (1)
- Fungal decay (1)
- Fungi (1)
- Fungicidal property (1)
- Fungiculture (1)
- Fungus (1)
- Fusarium (1)
- Gas storage (1)
- Gene expression (1)
- Genome sequence (1)
- Geological formation (1)
- Geology (1)
- Graphene (1)
- Graphene–bacteria interaction (1)
- Growth-rate homeostasis (1)
- Gut symbionts (1)
- HI-Tension (1)
- Halogenation (1)
- Halophilic (1)
- Halophilic bacteria (1)
- Healthcare (1)
- Herteogeneous phenotypes (1)
- High density polyethylene (1)
- High salinity (1)
- Holzschutzmittel (1)
- Hospital premises (1)
- Hydrogen (1)
- Hydrogen permeation (1)
- Hydrogen storage (1)
- Hydrogenasen (1)
- Hydrophobic interaction (1)
- Hylotrupes bajulus (1)
- Hylotrupes bajulus, Anobium punctatum, natural durability, tropical wood, native wood. (1)
- Hyperarid (1)
- Hypopharynx (1)
- IPM in museums (1)
- IR spectroscopy (1)
- ISO22196 (1)
- Implants (1)
- In situ (1)
- Industrial applications (1)
- Infections (1)
- Initial attachment (1)
- Insect evolution (1)
- Insecticide (1)
- Interdisciplinarity (1)
- Interdisciplinary (1)
- Iodine (1)
- Ionic liquid (1)
- Ionizing radiation (1)
- Issues (1)
- Laboratory breeding (1)
- Labrum (1)
- Lake Cadagno (1)
- Laser structuring (1)
- Laser-induced nanostructures (1)
- Laser-induced pariodic surface structures (1)
- Laser-induced periodic surface structueres (LIPPS) (1)
- Laser-modified surface (1)
- Library pests (1)
- Lifetime (1)
- Lightning talk (1)
- Limnoria spp (1)
- Low alloy steel (1)
- MDG ICP-ToF-MS (1)
- MIC Island (1)
- MIC projekt (1)
- Marek's virus (1)
- Marine borers (1)
- Material degradation (1)
- Materials (1)
- Mechanosensitive channel (1)
- Melting point (1)
- Melting temperature (1)
- Metabolic engineering (1)
- Metabolic flux analysis (1)
- Metabolic modeling (1)
- Metabolomics (1)
- Metal organic frameworks (1)
- Metal reducing bacteria (1)
- Metalls (1)
- Methane (1)
- Methanogenesis (1)
- Microbial (1)
- Microbial adhesions (1)
- Microbial community modelling (1)
- Microbial simulation, (1)
- Microbially Induced Corrosion (1)
- Microbiologically Influrenced Corrosion (MIC) (1)
- Microdroplet generator (1)
- Microfluidics (1)
- Micromonospora aurantiaca (1)
- Micropatterning (1)
- Microwaves (1)
- Migration (1)
- Mircobially influcenced corrosion (1)
- Modeling (1)
- Modified mycotoxins (1)
- Moisture (1)
- Moisture performance (1)
- Molecular (1)
- Molecular clock (1)
- MscS (1)
- Mud volcanoe fluids (1)
- Multi-resistant bacteria (1)
- Multiple lines of evidence (1)
- Multiport (1)
- Museum Pests (1)
- Museum insect pest (1)
- Museum pests (1)
- Mussel-inspired coating (1)
- Mussel-inspired materials (1)
- Mycotoxin (1)
- Mycotoxins (1)
- Nano Particles (1)
- Nano characterization (1)
- Nano metal fluorides (1)
- Nanobiocide (1)
- Nanocoating (1)
- Nanorods (1)
- Natural durability (1)
- Natural products discovery (1)
- Near ambient pressure XPS (1)
- Near ambient x-ray photoelectron spectroscopy (1)
- Next generation sequencing (1)
- Nitrous oxide (1)
- Nonvolatile (1)
- Nuclear waste disposal (1)
- Oil and gas industry (1)
- Oil and gas reservoir (1)
- Oilfield (1)
- One-step ionic liquids synthesis (1)
- Optical and Magnetic Materials (1)
- Osmophobic effect (1)
- Osmotic shock (1)
- Osteogenesis (1)
- P. Fluorescens (1)
- PE-HD (1)
- Paper sizings (1)
- Particle synthesis (1)
- Pathogen spillover (1)
- Pathogen transmission (1)
- Performance (1)
- Permeability (1)
- Persian historical recipes (1)
- Persian manuscripts (1)
- Pest control (1)
- Phenotypic heterogeneity (1)
- Phenotypic variation (1)
- Photodynamic therapy (1)
- Photonics (1)
- Physical and optical characteristics (1)
- Plastic degradation (1)
- Polydopamine (1)
- Polyethylene terephthalate (1)
- Polyglycerol (1)
- Polyioinic liquid (1)
- Polymer foils (1)
- Polymer-based products (1)
- Poster presentation (1)
- Preferential binding (1)
- Preferential exclusion (1)
- Proteome (1)
- Pseudomonas (1)
- Pseudomonas fluorescens (1)
- Pseudomonas veronii (1)
- Ptinidae (1)
- Quasispecies (1)
- RNA-Sequencing (1)
- Radio waves (1)
- Reactor conditions (1)
- Resistance model (1)
- Rhizopus (1)
- Rhizopus and Aspergillus oryzae (1)
- Rhodonia placenta (1)
- Round robin test (1)
- Ruthenium (1)
- SEM (1)
- SEM micrography (1)
- SEM wood characterization (1)
- SEM-EDS (1)
- SIMS (1)
- SRB (1)
- Selection (1)
- Self-assembled monolayer (1)
- Sensors (1)
- Silica and polystyrene nanoparticles (1)
- Silver (1)
- Single cell microbiology (1)
- Sizing (1)
- Social immunity (1)
- Social insects (1)
- Software (1)
- Soil contact (1)
- Soldier (1)
- Solitary bees (1)
- Solubility (1)
- Solute excretion (1)
- Spectral imaging (1)
- Stainless steel (1)
- Stakeholder (1)
- Standardisation (1)
- Standardized test and quantification procedure (1)
- Structural color (1)
- Superhydrophilic surface (1)
- Superhydrophobic surface (1)
- Suppression (1)
- Surface functionalization (1)
- Survival rates (1)
- Symbiosis (1)
- Synchrotron-XPS (1)
- Synergy (1)
- Synthetic metabolism (1)
- Teredo sp (1)
- Termite control (1)
- Termite-associated microbes (1)
- Termitoidae (1)
- Thermodynamic (1)
- Thioimidazolium (1)
- ToF SIMS (1)
- ToF-SIMS (1)
- Touch surfaces (1)
- Trait-based ecology (1)
- Transcriptomics (1)
- Ultrashort laser processing (1)
- Ultrastructure (1)
- Velocimetry (1)
- Virology (1)
- Virulence (1)
- Viruses (1)
- Water (1)
- Water atmosphere (1)
- Water stable isotope analysis (1)
- Water uptake (1)
- White-rot fungi (1)
- Wood Modification (1)
- X-ray spectroscopic techniques (1)
- X-ray tomographic (1)
- XANES (1)
- Xestobium rufovillosum (1)
- Zearalenone (1)
- Zearalenone sulfate (1)
- a-zearalenol (1)
- biocide tolerance (1)
- disinfection (1)
- dsDAN monolayer (1)
- evolution (1)
- fs-laser processing (1)
- heterogeneity (1)
- iChip (1)
- pH probe (1)
- underexplored phyla (1)
Organisationseinheit der BAM
- 4.1 Biologische Materialschädigung und Referenzorganismen (238) (entfernen)
Paper des Monats
- ja (6)
Eingeladener Vortrag
- nein (73)
Coastal oceans receive large amounts of anthropogenic fixed nitrogen (N), most of which is denitrified in the sediment before reaching the open ocean. Sandy sediments, which are common in coastal regions, seem to play an important role in catalysing this N‐loss. Permeable sediments are characterized by advective porewater transport, which supplies high fluxes of organic matter into the sediment, but also leads to fluctuations in oxygen and nitrate concentrations. Little is known about how the denitrifying communities in these sediments are adapted to such fluctuations. Our combined results indicate that denitrification in eutrophied sandy sediments from the world's largest tidal flat system, the Wadden Sea, is carried out by different groups of microorganisms. This segregation leads to the formation of N2O which is advectively transported to the overlying waters and thereby emitted to the atmosphere. At the same time, the production of N2O within the sediment supports a subset of Flavobacteriia which appear to be specialized on N2O reduction. If the mechanisms shown here are active in other coastal zones, then denitrification in eutrophied sandy sediments may substantially contribute to current marine N2O emissions.
The application of naturally-derived biomolecules in everyday products, replacing conventional synthetic manufacturing, is an ever-increasing market. An example of this is the compatible solute ectoine, which is contained in a plethora of treatment formulations for medicinal products and cosmetics. As of today, ectoine is produced in a scale of tons each year by the natural producer Halomonas elongata. In this work, we explore two complementary approaches to obtain genetically improved producer strains for ectoine production. We explore the effect of increased precursor supply (oxaloacetate) on ectoine production, as well as an implementation of increased ectoine demand through the overexpression of a transporter. Both approaches were implemented on an already genetically modified ectoine-excreting strain H. elongata KB2.13 (ΔteaABC ΔdoeA) and both led to new strains with higher ectoine excretion. The supply driven approach led to a 45% increase in ectoine titers in two different strains. This increase was attributed to the removal of phosphoenolpyruvate carboxykinase (PEPCK), which allowed the conversion of 17.9% of the glucose substrate to ectoine. For the demand driven approach, we investigated the potential of the TeaBC transmembrane proteins from the ectoine-specific Tripartite ATP-Independent Periplasmic (TRAP) transporter as export channels to improve ectoine excretion. In the absence of the substrate-binding protein TeaA, an overexpression of both subunits TeaBC facilitated a three-fold increased excretion rate of ectoine. Individually, the large subunit TeaC showed an approximately five times higher extracellular ectoine concentration per dry weight compared to TeaBC shortly after its expression was induced. However, the detrimental effect on growth and ectoine titer at the end of the process hints toward a negative impact of TeaC overexpression on membrane integrity and possibly leads to cell lysis. By using either strategy, the ectoine synthesis and excretion in H. elongata could be boosted drastically. The inherent complementary nature of these approaches point at a coordinated implementation of both as a promising strategy for future projects in Metabolic Engineering. Moreover, a wide variation of intracelllular ectoine levels was observed between the strains, which points at a major disruption of mechanisms responsible for ectoine regulation in strain KB2.13.
Halomonas elongata is a halophilic γ-proteobacterium that synthesizes and accumulates the compatible solute ectoine to cope with osmotic stress in saline environments. Ectoine possesses protecting properties and stabilizes proteins as well as whole cells against stresses like ionizing radiation and cytotoxins. These properties make ectoine a highly demanded ingredient in cosmetics and pharmaceuticals. To date H. elongata is the industrial Producer strain of ectoine, but several metabolic factors for optimum ectoine production remain to be explored.
In this work, we used up to date Metabolic engineering approaches following the ‘Push, Pull, Block – strategy’ to examine targets that contribute to ectoine synthesis. Firstly, the basics of glucose catabolism were inspected to PUSH and enhance carbon flow towards ectoine synthesis. Secondly, lysine biosynthesis was targeted to BLOCK a pathway that is competing for precursors with ectoine synthesis. Thirdly, the mechanosensitive (MS) channels of H. elongata have been examined as possible excretion routes for ectoine. An overexpression of the ectoine excretion channels potentially could PULL out product at the end of ectoine synthesis and increase overall ectoine flux. For the interrogation of central metabolic pathways, we established the new molecular tool CRISPR-mediated interference (CRISPRi) for targeted modulation of gene expression.
PUSH Glucose catabolism through the Entner-Doudoroff (ED) and Emden-Meyerhof-Parnas (EMP) pathway was targeted with CRISPRi and examined on gene expression level for ist response to changing salinity and different carbon sources. Changing salinity did not influence gene expression levels of glucose catabolism but the carbon source glucose triggered glycolysis through the (ED) pathway. When gene expression of the ED pathway was downregulated with CRISPRi, the growth rates remained constant. The observations indicate a metabolic overflow mechanism for glycolysis, in which fluxes are constantly high - even at lower salinity when no resources are demanded for ectoine synthesis. The further analysis of glucose to product conversion rates will advise optimum conditions for future industrial cultivation processes.
BLOCK Lysine biosynthesis was downregulated with CRISPRi, which led to a significant increase in ectoine production. Hence, the blockage of lysine biosynthesis would be a valuable strategy for the optimization of the industrial producer strain in future studies.
PULL MS channels and ectoine regulation are inevitably connected in osmoadaptation. Therefore, ectoine excretion, growth performance and gene expression levels of the MS channels were monitored in steady state conditions and in response to osmotic shock in the wildtype strain and in a MS channel deletion mutant. We observed that the MS channels were essential for the survival of osmotic shock but surprisingly their presence reduced cell growth under high salinity. The MS channels were only partially responsible for ectoine excretion.
Thus, alternative ectoine excretion channels must exist and remain to be explored.
Excessive discharge of quaternary ammoniumdisinfectants such as benzalkonium chloride (BAC) into aquatic systems can trigger several physiological responses in environmental microorganisms. In this study, we isolated a less-susceptible strain of Aeromonas hydrophila to BAC, designated as INISA09, froma wastewater treatment plant in Costa Rica. We characterized its phenotypic response upon exposure to three dierent concentrations of BAC and characterizedmechanisms related to its resistance using genomic and proteomic approaches. The genome of the strain, mapped against 52 dierent sequenced A. hydrophila strains, consists of approximately 4.6Mb with 4,273 genes. We found a massive genome rearrangement and thousands of missense mutations compared to the reference strain A. hydrophila ATCC 7966.
We identified 15,762 missense mutations mainly associated with transport, antimicrobial resistance, and outer membrane proteins.
In addition, a quantitative proteomic analysis revealed a significant upregulation of several efflux pumps and the downregulation of porins when the strain was exposed to three BAC concentrations.Other genes related tomembrane fatty acid metabolism and redox metabolic reactions also showed an altered expression.
Our findings indicate that the response of A. hydrophila INISA09 to BAC primarily occurs at the envelop level, which is the primary target of BAC. Our study elucidates the mechanisms of antimicrobial susceptibility in aquatic environments against a widely used disinfectant and will help better understand howbacteria can adapt to biocide pollution. To our knowledge, this is the first study addressing the resistance to BAC in an environmental A. hydrophila isolate. We propose that this bacterial species could also serve as a new model to study antimicrobial pollution in aquatic environments.
Microbiologically influenced corrosion (MIC) is a highly unpredictable process dictated by the environment, microorganisms, and the respective electron source. Interaction pathways between cells and the metal surface remain unclear. The development of this novel single cell-inductively coupled plasma-time of flight-mass spectrometry analytical method and a MIC-specific staining procedure facilitate the investigation of steel-MIC interactions. With this it is possible to analyze the multi-elemental fingerprint of individual cells. The detection method revealed elemental selectivity for the corrosive methanogenic archaeal strain Methanobacterium-affiliated IM1. The interface between material and environmental analysis thus receives special attention, e.g., when considering MIC on solid steel. Hence, the possible uptake of individual elements from different steel samples is investigated. Results showed the cells responded at a single-cell level to the different types of supplemented elements and displayed the abilities to interact with chromium, vanadium, titanium, cobalt, and molybdenum from solid metal surfaces. The information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials research.
The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers.
The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future Container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 106 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel.
In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.
This study details a theoretical analysis of leaky and waveguide modes in biperiodic all-dielectric holograms. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a new class of highly sensitive refractive index biosensing platforms that are capable of resolving 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes.
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.
Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms, often with enhanced resistance towards antimicrobial treatment and established cleaning procedures. On e.g. medical implants, in water supply networks or food-processing industry, biofilms can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. Nowadays, the emergence of resistances because of extensive usage of antibiotics and biocides in medicine, agriculture and private households have become one of the most important medical challenges with considerable economic consequences. In addition, aggravated biofilm eradication and prolonged cell-surface interaction can lead to increased biodeterioration and undesired modification of industrial and medical surface materials. Various strategies are currently developed, tested, and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics.
In this study, contact-less and aseptic large-area short or ultrashort laser processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials such as titanium-alloy and polyethylene terephthalate (PET). The laser processed surfaces were subjected to bacterial colonization studies with Escherichia coli test strains and analyzed with reflected-light and epi-fluorescence microscopy. Depending on the investigated surfaces, different bacterial adhesion patterns were found, ranging from bacterial-repellent to bacterial-attractant effects. The results suggest an influence of size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself, emphasizing the potential of laser-processing as a versatile tool to control bacterial surface adhesion.
We demonstrate a 2D platform based on high contrast wetting patterns suitable for miniaturized microbiological assays.
In principal, superhydrophilic spots are surrounded by a superhydrophobic surface area. The special structure of the superhydrophilic functional surface ensures that liquids, e.g. bacterial suspensions or biocide solutions, spread immediately and evenly on this surface without passing the wetting boundary. This feature allows a homogenous distribution of bacteria or chemical substances on well defined lateral dimensions. The superhydrophilic spots may also serve as substrate for bacterial biofilms. Due to the high wetting contrast and the fabrication process, it is possible to minimize the test areas as well as their distance to each other.
We demonstrate the fabrication process of the high wetting contrast platform and also present a microbiological assay as an application example. Advantages of this platform are the use of low volumes and its potential of automated analysis.
The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth Tineola bisselliella provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to Bacillus sp. FDAARGOS_235. Genome Annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of T. bisselliella larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.
Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated.
Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera, Ptinidea, formerly Anobiidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identified. At 21 °C and 75 % relative humidity and a four-month cold period at 4 °C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behavior of adult K. caeruleus was not investigated.
The role of methanogens in microbiologically influenced corrosion (Mi-MIC) is often neglected, due to 1) low reported corrosion rates and 2) the suspected corrosion product siderite, which is electrically non-conductive. Typically, MIC corrosion studies are carried out using batch cultures, which did not represent the dynamic conditions, i.e. pipeline and provide insufficient information on the overall corrosion potential.
We established a unique approach, a multiport flow column (MFC), to simulate pipeline conditions and obtained 10-times higher corrosion rates than previously published. Our result showed that testing procedures have a large impact on the corrosive potential of methanogens. We found strong indications with a combination of ToF-SIMS, SEM-EDS and FIB-SEM analyses that siderite is not the sole corrosion product. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of other environmental parameters (e.g. pH) on Mi-MIC.
Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows under certain conditions methanogenic archaea can cause higher corrosion than SRB, specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and that spatial statistical evaluations of MIC can be carried out.
X-ray photoelectron spectroscopy (XPS) provides elemental and chemical information from the outermost ~10 nm of the sample surface. This is in the same order of magnitude as the thickness of the outer bacterial membrane of gram-negative bacteria, as well as outer membrane molecules as exopolysaccharides and lipopolysaccharides, commonly attached to the cell surface. With the development of near-ambient pressure (NAP)-XPS, bacteria can be analysed with minimal sample preparation.
EnviroESCA is a laboratory based NAP-XPS instrument, equipped with a monochromated Al Kα radiation source and a differentially pumped energy analyser connected to an exchangeable sample environment. It allows for measurements in various gas-atmospheres, including water vapor, which makes it possible to characterise bacteria and other biological samples close to their natural, hydrated state. Artificial model-biofilms of exopolysaccharides, planktonic Pseudomonas Fluorescens and biofilms of Escherichia Coli have been characterised in hydrated and dried state.
High-resolution XPS-spectra from carbon, oxygen, nitrogen and phosphorous can be assigned to carbohydrates, lipids and proteins in general agreement with literature. Especially the carbon 1s peak is of interest. A series of measurements of an E. coli biofilm from 11 mbar in humid environment to 1 mbar air reveal changes in the C1s peak, which suggests that the bacterial surface undergo substantial Change.
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.
The influence of interfacial pH between AISI 4135 steel and seawater under different polarization potentials on the formation of calcareous deposits has been studied. An interfacial pH of 9.61 at −0.9 V vs. SCE using state of the art iridium oxide microelectrode was found to be the critical pH for the precipitation of magnesium hydroxide. Calcareous deposits with a double-layer structure comprising an inner-brucite layer and an outer-aragonite layer were found to form at potentials between −1.0 V and −1.2 V vs. SCE. Furthermore, the facilitation of hydrogen permeation into steel induced by the formation of calcareous deposits was verified using the Devanathan-Stachurski electrochemical test. The mechanism of calcareous deposits facilitates hydrogen permeation into steel is related to its inhibition on hydrogen recombination and escape processes.
Aim of study: In this study, natural durability of some domestic and foreign wood species against Hylotrupes bajulus and Anobium punctatum larvae were tested on laboratory scale
Area of study: This study was conducted at Department of Forest Products Engineering in Duzce University, Turkey and Federal Institute for Materials Research and Testing (BAM), Germany.
Material and Methods: Scotch pine (Pinus sylvestris), fir (Abies nordmanniana), spruce (Picea orientalis), cedar (Cedrus libani), poplar (Populus tremula) and beech (Fagus orientalis) woods were used to test H. bajulus larvae (EN 46-1). Alder (Alnus glutinosa), oak (Quercus cerris), poplar (Populus tremula), beech (Fagus orientalis), maple (Acer carpinifolium), ash (Fraxinus angustifolia), teak (Tectona grandis), ayous (Triplochiton scleroxylon), movingui (Distemonanthus benthamianus), dahoma (Piptadeniastrum africanum), iroko (Chlorophora excelsa), bubinga (Guibourtia tessmannii) and sapele (Entandrophragma cylindiricum) woods were used for A. punctatum larvae (EN 49-1). At the end of the experiment, the mortality rates of the larvae were determined and the size and weights of the surviving larvae were measured.
Main results: F. orientalis and C. libani were found to be the most resistant wood species against H. bajulus larvae while A. nordmanniana was the least resistant. All tropical wood species and oak and maple from domestic wood species showed 100% mortality rate therefore found to be the most resistant against A. punctatum larvae. The most vulnerable wood species was found to be alder with a 35% mortality.
Research highlights: while F. orientalis, C. libani, and P. tremula were found the most resistance wood species against H. bajulus, P. sylvestris and A. nordmanniana were determined as most vulnerable. All tropical wood species and two domestic species (Q. cerris and A. carpinifolium) showed the highest mortality rate as 100%. The least durable domestic wood was determined as alder.