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Fluorophore labeled proteins and antibodies, referred to also as targeted optical probes, present a promising strategy for a variety of applications from fundamental cell-based biological studies to in vivo diagnostics and image guided surgeries in humans. In this respect, design strategies for the preparation of such conjugates from different dyes including analyte-responsive fluorophores are presented as well as their analytical and spectroscopic characterization employing Absorption spectroscopy and steady state and time-resolved fluorometry. Special emphasis is dedicated to the influence of dye hydrophilicity and labeling density on the optical properties and binding behavior of these dye-bioconjugates including their performance in in vitro and in vivo bioimaging studies.
An Annex XV restriction dossier for cadmium in artists’ paints was submitted by an EU member state to the European Chemicals Agency ECHA. By cleaning used brushes under the tap cadmium can enter the food chain via waste water treatment and subsequent agricultural application of the sewage sludge. It was estimated that 110 kg Cd per year is spread on agricultural land via this exposure route. Other sources of Cd amount to almost 120 tons per year.
The mobility of Cd from pigments was studied in a field-like scenario by leaching experiments using soil samples amended with sewage sludge and spiked with Cd pigments in percolation columns. The redox conditions were confirmed to be the decisive factor for the release of Cd. The release of Cd from artists’ paints was in most cases 1% or lower in the experiments performed.
Cd from artists’ paints in sewage sludge applied in agriculture will be mobilized for intake by crops or to leaching either by oxidation of sulfide to sulfate or by dissolution at lower pH values. The quantity of Cd from artists’ paints calculated in the restriction dossier is however negligible compared to other sources of Cd to agricultural soil. Therefore ECHA did not consider the proposed restriction to be the most appropriate EU wide measure to address the negligible level of risk. In the presentation sources of Cd on agricultural land will be discussed together with possible policy instruments to mitigate such emissions.
It is thought that the primary function of soldier castes in insect societies is to protect colonies against macroscale predators and parasites. By comparison, little attention has been paid to the role of soldiers against pathogenic microorganisms. This is a significant gap in knowledge because in non-hymenopteran societies, such as the eusocial termites, the first-evolved, and arguably most important sterile caste, is the soldier.
Here, we investigate whether soldiers of the wood-eating termite, Mastotermes darwiniensis, play a significant role in social immunity. Firstly, we show that uninfected soldiers improve the survival of worker nestmates exposed to a lethal dose of a fungal pathogen, despite the fact that soldiers (unlike workers) cannot allogroom. Hazard ratios of pathogen-exposed workers decreased from 6.616 in infected groups to 4.376 and 2.786 in infected groups containing uninfected workers and soldiers, respectively. To explore the basis of soldier protection, we applied soldier-derived oral secretions to infected worker cuticle, resulting in significantly improved worker survival. Soldiers that contacted infected workers were also more active and produced secretions with significantly greater mass variance than soldiers exposed to uninfected workers.
Significantly, we show that secretions produced by soldiers inhibit the growth of a broad range of microorganisms, including gram-negative and gram-positive bacteria, in addition to fungi. Our findings demonstrate that soldiers can contribute powerful antimicrobial factors to external immune defenses, effectively complementing behaviour-based protective activities provided by workers.
In addition to individual immunity, social insects have evolved collective defence strategies against pathogens, which consist of behavioural, physiological and organisational adaptations. The importance of social immunity in preventing disease transmission in insect societies is well known. However, we still lack a clear understanding of how collective defence mechanisms are regulated and how they interact with the other regulatory systems of the organism such us the individual immune system. Here we assess how individual immune factors shape the collective immune response to pathogens by inhibiting a key Termite immune effector: gram-negative binding protein (tGNBP-2). tGNBP-2 triggers downstream innate immunity, in addition to cleaving fungal and bacterial pathogens directly in the external environment. We established mini-colonies of Reticulitermes flavipes inside planar arenas where we were able to observe and record hygienic behaviours (i.e. allogrooming and cannibalism) in near-natural nest conditions. Colonies were either treated with the tGNBP-2 inhibitor or a control solution, after which 5 focal workers were introduced into each colony. Focal workers were pre-exposed to either: 1) the fungal pathogen Metharizium anisopliae 2) the t-GNBP-2 inhibitor + M. anisopliae 3) a control solution. Colonies were recorded and the hygienic behaviours performed by nestmates towards focal termites were analysed. We examined the impact of tGNBP-2 inhibition on individual innate immune regulation, in addition to exploring the wider impact of immune suppression on collective social behavioural responses.
Due to the increasing presence of microplastic particles (MP) in the Environment and the unknown risks arising from them, there is an urgent need for analytical methods that allow for an efficient identification and quantification of microplastics (MP), i.e. particles < 5 mm, in environmental samples. So far, mostly timeconsuming (micro) infrared or micro-Raman spectroscopic methods are applied. Here an faster alternative Approach is presented based on a Raman processspectrometer with fiber-optical probes in combination with multivariate data analysis.
A 400 m² soil test field with gas injection system was built up, which enables an experimental validation of linear gas sensors for specific applications and gases in an application-relevant scale. Several injection and soil watering experiments with carbon dioxide (CO2) at different days with varying boundary conditions were performed indicating the potential of the method for, e.g., rapid leakage detection with respect to Carbon Capture and Storage (CCS) issues.
Prospects and Restrictions of the Metal Magnetic Memory Technique
Biocide leaching was investigated for acrylate and vinyl acetate based coatings containing biocides either as liquid formulations or microcapsules. Laboratory and field tests indicate similar relations of results on carbendazim, diuron, terbutryn and OIT from different coatings in laboratory and field experiments. Emissions were higher in EN 16105 laboratory tests than from vertically installed test specimens exposed to weathering, and slower for microencapsulated biocides. Competing processes that cause losses of active substances can occur in both tests, but to a higher degree in field experiments. Emission curves related to runoff water were similar in repeated field experiments. Relative humidity, temperature and global radiation were identified as meteorological factors that affect leaching by complex interaction besides the amount of driving rain.
Biocide leaching was investigated for acrylate and polymer based coatings containing biocides either as liquid formulations or microcapsules. Laboratory and field tests indicate similar relations of results on carbendazim, diuron, terbutryn and OIT from different coatings in laboratory and field experiments. Emissions were higher in EN 16105 laboratory tests than from vertically installed test specimens exposed to weathering, and slower for microencapsulated biocides. Competing processes that cause losses of active substances can occur in both tests, but to a higher degree in field experiments. Emission curves related to runoff water were similar in repeated field experiments. Relative humidity, temperature and global radiation were identified as meteorological factors that affect leaching by complex interaction besides the amount of driving rain.
There is significant contamination of our water resources and an accelerating accumulation of hazardous species in the aquatic biosphere. Whether for instance mercury as a contaminant constantly released from a multitude of industrial processes or chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB) or Soman (GD) as highly toxic remnants of World War II, released from dumped containers upon their progressive corrosion, are concerned such hazards can cause serious problems to human health even at low concentration and monitoring them becomes increasingly essential. Conclusively, it is necessary to develop sensors for such hazards that combine high sensitivity, good selectivity, fast responses and can dispense with complex instrumentation.
Here, we present SBA-15-type mesoporous silica materials containing boron–dipyrromethene (BODIPY) probes in their pore systems that allow for the sensitive and selective detection of the two target analytes CWAs and Hg2+ in natural waters via a change in the optical properties. In case of Hg2+, the BODIPY dye is directly adsorbed on the (inner and outer) surface of the highly porous material and coordinates the metal ion, leading to an enhancement of fluorescence with a limit of detection (LOD) of 15 ppt. Using the same silica material but incorporating a covalently attached BODIPY dye, the CWAs GA, GD and GB can be detected via fluorescence quenching induced by an intraannular cyclization. The obtained LOD in natural waters is in the pM range and hence below the Maximum Permissible Concentrations for CWAs in drinking water. Aspects of system design as well as application in water and food analysis (fish extracts) will be presented.
There is significant contamination of our water resources and an accelerating accumulation of hazardous species in the aquatic biosphere. Whether for instance mercury as a contaminant constantly released from a multitude of industrial processes or chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB) or Soman (GD) as highly toxic remnants of World War II, released from dumped containers upon their progressive corrosion, are concerned such hazards can cause serious problems to human health even at low concentration and monitoring them becomes increasingly essential. Conclusively, it is necessary to develop sensors for such hazards that combine high sensitivity, good selectivity, fast responses and can dispense with complex instrumentation.
Here, we present SBA-15-type mesoporous silica materials containing boron–dipyrromethene (BODIPY) probes in their pore systems that allow for the sensitive and selective detection of the two target analytes CWAs and Hg2+ in natural waters via a change in the optical properties. In case of Hg2+, the BODIPY dye is directly adsorbed on the (inner and outer) surface of the highly porous material and coordinates the metal ion, leading to an enhancement of fluorescence with a limit of detection (LOD) of 15 ppt. Using the same silica material but incorporating a covalently attached BODIPY dye, the CWAs GA, GD and GB can be detected via fluorescence quenching induced by an intraannular cyclization. The obtained LOD in natural waters is in the pM range and hence below the Maximum Permissible Concentrations for CWAs in drinking water. Aspects of system design as well as application in water and food analysis (fish extracts) will be presented.
Concrete is one of the most widely used construction materials and, accordingly, the concrete industry is an important stakeholder in the field of sustainable construction. Therefore various approaches have been implemented to increase the sustainability of concrete. Besides reducing CO2-emissions during cement production, increasing the energy efficiency of buildings and extending their life span, the end-of-life performance of concrete is also an essential aspect of sustainability. Reusing concrete as a secondary building material meets the requirements of sustainability in several ways: the extended time availability of primary raw materials and, thereby, the protection of natural resources as well as conserving landfill site. Furthermore, the production of recycled concrete aggregates (RCA) is a good example for closed-loop recycling.
However, regarding the use of RCA as a substitute for natural aggregates in concrete, attention must be paid to all issues of sustainability: this means that environmental, economic and social aspects have to be considered. Since RCA generally have inferior building material properties, such as higher porosity and lower density, the implementation of closed-loop recycling of concrete only makes sense if the technical quality assurance is secured. This paper focusses on the implementation of techniques for the deconstruction/demolition of buildings and the subsequent treatment of concrete rubble in order to improve the building material properties of RCA with regard to the requirements of sustainability and also technical rules and standards.
Concrete is one of the most widely used construction materials and, accordingly, the concrete industry is an important stakeholder in the field of sustainable construction. Therefore various approaches have been implemented to increase the sustainability of concrete. Besides reducing CO2-emissions during cement production, increasing the energy efficiency of buildings and extending their life span, the end-of-life performance of concrete is also an essential aspect of sustainability. Reusing concrete as a secondary building material meets the requirements of sustainability in several ways: the extended time availability of primary raw materials and, thereby, the protection of natural resources as well as conserving landfill site. Furthermore, the production of recycled concrete aggregates (RCA) is a good example for closed-loop recycling.
However, regarding the use of RCA as a substitute for natural aggregates in concrete, attention must be paid to all issues of sustainability: this means that environmental, economic and social aspects have to be considered. Since RCA generally have inferior building material properties, such as higher porosity and lower density, the implementation of closed-loop recycling of concrete only makes sense if the technical quality assurance is secured. This paper focusses on the implementation of techniques for the deconstruction/demolition of buildings and the subsequent treatment of concrete rubble in order to improve the building material properties of RCA with regard to the requirements of sustainability and also technical rules and standards.
Due to the large quantities of construction and demolition waste (CDW) in Europe, its reuse or recycling is of particular importance. Although several countries already recycle high amounts of CDW, the use as secondary raw materials is often limited by inferior building material properties. Specific characteristics, like high porosity and low density are caused by hardened cement paste in crushed concrete and the content of mortar and plaster in brick debris. Impurities like wood or gypsum and also harmful substances like organic pollutants may be a major problem for a reuse and should be minimized. Therefore unwanted materials and impairing substances have to be separated from the secondary building material stream. This can be done during the demolition process by using techniques for selective dismantling or during the subsequent treatment of the resulting rubble. Since almost all processing steps are associated with environmental impacts, the benefits of saving natural resources by applying secondary building materials should be weighed carefully. An environmental performance evaluation was undertaken to assess different techniques for reducing gypsum in recycled concrete aggregates, aiming at a minimization of elutable sulfates. These results were compared to the environmental impacts of the extraction of natural aggregates for concrete.
2,4-Dichlorophenoxyacetic acid (2,4-D) is one important and well-known herbicide that is widely used in agriculture because of its advantages to regulate plant growth. However, the use of large quantities of the treated plants as animal feed leads to residues in meat, milk and eggs. Furthermore, the herbicide can drain away and contaminate ground and drinking water. The ingestion of 2,4-D-contaminated food and water causes damage to the inner organs of humans and animals, e.g., the kidneys and the liver.
Analytical assays based on molecularly imprinted polymers (MIPs) have emerged as a valuable tool in the field of environmental analysis due to the low production costs, stability, format adaptability and the possibility to imprint and thus their ability to recognize a wide variety of target analytes.5 With regard to optical sensing technologies, however, MIPs have only been used in considerably few applications, especially in fluorescence sensors. This limitation is basically due to the fact that the incorporation of a fluorescently responding moiety into a polymer matrix is challenging. One way to overcome this limitation is to use tailor-made fluorescent indicator monomers for direct transfer of the binding event into an optical signal and coat the MIP via reversible addition-fragmentation chain transfer (RAFT) polymerization as a thin layer onto the surface of silica nanoparticles as primary sensing element.
Here, we present the response behavior of the fluorescent MIP sensor particles in terms of sensitivity for 2,4-D detection (the so-called imprinting factor), discrimination ability against structurally similar compounds and performance in a phase-transfer assay (PTA) on chip, i.e., the implementation of the assay into a microfluidic chip environment, offering a novel simple and rapid way for the detection of herbicides.
The pollution of the environment with microplastics MP (particles < 5mm) is a problem of increasing concern.1 A consistent methodology that facilitates detection of MP is still missing. Here we present the data recorded by applying different MP identification methods to a soil fortified with known amounts of MP.
Fungal extracellular materials reinforce a constant interaction between their cell wall and the environment. A dynamic mixture of chitin, glucans, mannans, glycoproteins, glycolipids and pigments supports the success of all fungal life styles – from symbiotic to the free-living and pathogenic. Fungi are perfectly adapted to grow on surfaces and in porous environments, where they form medically and geochemically relevant biofilms. Fungal EPS are critical in adhesion to other fungi, other cells or substratum as well as in the following interaction with the host immune system or material they attack, degrade and deteriorate respectively. Characterisation of extracellular compounds and understanding of its function is necessary to limit damage caused by fungal activity. All necessary methodology from chemical characterization to complete genetic analyses has been developed for medically important fungi. Now it is time to apply this knowledge to the numerous, largely aerobic and very active organisms that occupy a wide range of atmosphere-exposed habitats in the upper lithosphere. One can expect that analogies between medically- and environmentally-relevant model fungal species will help us to address the dynamics of the fungal cell EPS matrix in much more efficient and widely applicable ways.
Some results of our measurements of the Intercity experimental are presented together with simulated results and their interpretation. Three frequeny ranges could be measured and calculated: low frequencies which decrease very rapidly with distance (the quasi-static part), high frequencies (mainly due to the sleeper passage), and a mid-frequency which has the weakest attenuation with distance and is therefore dominant at the far field. Mono-frequent excitations get a wide frequency band due to the Doppler effect of the moving high-speed train.
Biofilms living on gold (Au) grains play a key role in the biogeochemical cycle of Au by promoting the dispersion of Au via the formation of Au nanoparticles as well as the formation of secondary biomorphic Au. Gold grains from Queensland, Australia, are covered by a polymorphic, organic-inorganic layer that is up to 40 μm thick. It consists of a bacterial biofilm containing Au nanoparticles associated with extracellular polymeric substances as well as bacterioform Au. Focused ion beam (FIB) sectioning through the biofilm revealed that aggregates of nanoparticulate Au line open spaces beneath the active biofilm layer. These aggregates (bacterioform Au type 1) resulted from the reprecipitation of dissolved Au, and their internal growth structures provide direct evidence for coarsening of the Au grains. At the contact between the polymorphic layer and the primary Au, bacterioform Au type 2 is present. It consists of solid rounded forms into which crystal boundaries of underlying primary Au extend, and is the result of dealloying and Ag dissolution from the primary Au. This study demonstrates that (1) microbially driven dissolution, precipitation, and aggregation lead to the formation of bacterioform Au and contribute to the growth of Au grains under supergene conditions, and (2) the microbially driven mobilization of coarse Au into nanoparticles plays a key role in mediating the mobility of Au in surface environments, because the release of nanoparticulate Au upon biofilm disintegration greatly enhances environmental mobility compared to Au complexes only.
The role of c-di-GMP in biofilm formation of the filamentous cyanobacterium Nostoc punctiforme
(2016)
The signaling molecule c-di-GMP is a ubiquitous second messenger in bacterial species including cyanobacteria. C-di-GMP stimulates the biosynthesis of extracellular polymeric substances (EPS) in biofilms and regulates the transition between a motile and a sessile life style in many bacteria. In our study we focus on c-di-GMP function and EPS production associated with biofilm Formation in Nostoc punctiforme, which is known to produce EPS in biofilms and liquid culture.
Among the borates in the Middle European Zechstein Salt Succession boracite Mg3[B7O13Cl] is the most common mineral in quantity and local distribution. An exceptional enrichment is observed in Stassfurt Serie Z2) in the Stassfurth seam K2H. Boracite is to be found in two varieties: individual crystals in cubic, tetrahedral or dodecahedral habit on the one hand and fibrous crystals so-called “stassfurtite” on the other hand. The formation conditions such widely spread borates in the salt succession are ambiguous in two respects. First of all the synthetic formation of boracites is to be made by hydrothermal or melt conditions. Both processes can be suspended for the salt succession. Furthermore the cubic modification is stable above 265°C for the Mg-boracite. The cubic, tetrahedral or dodecahedral habit could be used as a geothermometer, but such conditions can be exclude by the paragenetic minerals, esp. carnallite (MgKCl3 x 6H2O). The chemical composition of orthorhombic, pseudo-cubic boracite depends on the location. Pure Mg-boracite in hexahedral habit and in fibrous habit, so-called “stassfurtite”, occurs in the North Harz region, whereas the Fe-, Mn-, Mg-boracite appears in the South Harz region. Until now the source of boron, the time of formation of crystals, but also the reasons for the differences in habit of the single hexahedral crystals are still unclear. The formation during a diagenetic/metamorphic process is evident. However, the preferred formation in Stassfurt seam could be an indication for the boron enrichment in an early diagenetic process. Furthermore permit the determination of the thermal stability and the volatile content of crystals conclusions to the chemical composition of the fluid. The observed variation suggests that the condition of crystal growth as well as the chemical composition of fluid repeatedly changed over the time. Randomly occuring xenomorpheous anhydrite and magnesite inclusions within single boracite crystals have been interpreted as an indication to factors of chemical milieu during the formation of crystals. The reversible phase transition temperature of the boracite is a linearly function of the iron and manganese content and varies from 265°C for Mg-boracite to 330°C for Fe(Mn)-boracite. The thermal decomposition of boracite is determined by two processes. The decomposition started with a boron-chlorine release (BOCl?), having a maximum rate at 1050°C. Additionally to this release one observes a simultaneous emission of H2O, HCl, HF, CO2 , N2 , SO2 , H2 , and hydro carbons. The results give evidence for the aged approach of a secondary formation of boracite within the complete Stassfurt seam, possibly in connection with the formation of salt diapirs in the Jura and Cretaceous period. The wider environmental distribution of borates is an indication of chemical transport processes within the salt succession. This should be a more important issue in the discussion about the utilisation of salt diapirs for the storage of nuclear waste.
Microbiological biofilms on rocks are ubiquitous in nature and their influence on soil formation through rock weathering has been shown (Gorbushina 2007). However, most previous studies on rock weathering are limited to understanding the physical and chemical aspects overlooking the impact of biota. Due to the enormous amounts of variables that come with a biological process, the quantification of its influence is only possible by using well-controlled and simplified laboratory models. Thereby gaining more insight on the impact of rock inhabiting biofilms on mineral weathering. This presentation will show the impact of biotic weathering in terms of olivine dissolution rates
Natural forsterite was incubated in batch reactor flasks with and without a model consortium consisting of the phototrophic cyanobacterium Nostoc punctiforme and the rock-inhabiting ascomycete Knufia petricola, and submerged in a growth solution (pH 6). The flasks were incubated for 30 days under 25°C, 90 µmol photons/m2s and were shaken at 150 rpm. qPCR was performed to quantify the cell number of both organisms, BET to gather the specific surface of the used olivine and ICP-OES to follow up the change of concentration of the leached out metals.
Our results show that our model consortium, especially K. petricola does increase the dissolution rate of olivine. The pH increased from the initial 6 to around 7.2 for all setups. Initially Mg was preferentially released over Si (Mg/Si of 3.5), until after two days the ratio starts equilibrating around stoichiometric dissolution. During this timeframe the dissolution rate drops by nearly two orders of magnitude, just as observed by Daval et al., (2011). The difference in dissolution rates between the different setups is initially non-existent, but increases over time. After 30 days the setup with K. petricola gives a dissolution rate of 1.08 10-13 moles/cm2s, compared to 9.23 10-14 moles/cm2s for the abiotic setup.
We expect this study to cause awareness on the impact of microbiology on mineral weathering. Additionally it is a starting point for other, more complicated experiments using for instance flow through or drip flow reactors or other minerals.
Microcolonial fungi (MCF) are the most stress-resistant eukaryotes known to date. Black fungi are an interesting object to study mechanisms of stress resistance and to perform applied research to prevent material colonization and biodeterioration. Pigments, like melanin and carotenoids, have been proven to contribute to the unique robustness of MFCs. We study how these pigments ameliorate oxidative stress responses - one of the most significant environmental challenges encountered by MCF - using the model rock fungus Knufia petricola (Chaetothyriales) strain A95.
Genetic manipulation of protective pigments in a rock-inhabiting model fungus Knufia petricola A95
(2016)
Black ascomycetous microcolonial fungi are persistent inhabitants of rock surfaces, but are especially conspicuous in hostile environments like cold and hot deserts. The unique robustness of MFCs is supported by protective pigments, like melanin and carotenoids. We study the role of these pigments in the stress resistance of the model rock fungus Knufia petricola (Chaetothyriales) strain A95.
Microcolonial fungi (MCF) are able to survive extreme environmental conditions. This study is focusing on responses to oxidative stress - using the rock fungus Knufia petricola strain A95. Comparative gene expression analyses of a wild type and a PKS mutant are used to identify genes which are especially regulated under oxidative stress conditions to help elucidate mechanisms of cell wall maturation and oxidative stress defence strategies.
The industrial sector of incinerator bottom ash (IBA) treatment from municipal solid waste (MSW) is currently changing. Since established techniques are not yet suitable for fine grain sizes, pollutants are enriched and the effort for the treatment increases exponentially it is nowadays generally landfilled. Innovative treatment trains for the recovery of minerals and metals from the fine fraction will be presented and discussed. In fresh IBA this fraction < 2 mm amounts to around 25 % and contains different precious elemental and chemically bonded metals, especially copper. All copper species have higher densities compared to the bulk minerals. Investigations for the enrichment of copper carried out with a centrifugal classifier will be introduced.
Emerging infectious diseases (EIDs) have contributed significantly to the current biodiversity crisis, leading to widespread epidemics and population loss. Owing to genetic variation in pathogen virulence, a complete understanding of species decline requires the accurate identification and characterization of EIDs. We explore this issue in the Western honeybee, where increasing mortality of populations in the Northern Hemisphere has caused major concern. Specifically, we investigate the importance of genetic identity of the main suspect in mortality, deformed wing virus (DWV), in driving honeybee loss. Using laboratory experiments and a systematic field survey, we demonstrate that an emerging DWV genotype (DWV-B) is more virulent than the established DWV genotype (DWV-A) and is widespread in the landscape. Furthermore, we show in a simple model that colonies infected with DWV-B collapse sooner than colonies infected with DWV-A. We also identify potential for rapid DWV evolution by revealing extensive genome-wide recombination in vivo. The emergence of DWV-B in naive honeybee populations, including via recombination with DWV-A, could be of significant ecological and economic importance. Our findings emphasize that knowledge of pathogen genetic identity and diversity is critical to understanding drivers of species decline.
Emerging infectious diseases (EIDs) have contributed significantly to the current biodiversity crisis, leading to widespread epidemics and population loss. Owing to genetic variation in pathogen virulence, a complete understanding of species decline requires the accurate identification and characterization of EIDs. We explore this issue in the Western honeybee, where increasing mortality of populations in the Northern Hemisphere has caused major concern. Specifically, we investigate the importance of genetic identity of the main suspect in mortality, deformed wing virus (DWV), in driving honeybee loss. Using laboratory experiments and a systematic field survey, we demonstrate that an emerging DWV genotype (DWV-B) is more virulent than the established DWV genotype (DWV-A) and is widespread in the landscape. Furthermore, we show in a simple model that colonies infected with DWV-B collapse sooner than colonies infected with DWV-A. We also identify potential for rapid DWV evolution by revealing extensive genome-wide recombination in vivo. The emergence of DWV-B in naive honeybee populations, including via recombination with DWV-A, could be of significant ecological and economic importance. Our findings emphasize that knowledge of pathogen genetic identity and diversity is critical to understanding drivers of species decline.
Diverse animal species consume toxins, minerals or secondary compounds as an adaptive response to pathogen infection – a process termed self-medication. Recent studies have also shown that macronutrients can play an important role in an individual’s infection response. For instance African army worm caterpillars select a diet rich in protein and low in carbohydrate upon baculovirus infection. Here we investigate whether dietary choice of macronutrients also plays a role in immunity in the omnivorous cockroach: Blatta orientalis. After challenging individual cockroaches with a common entomopathogenic soil bacterium, Pseudomonas entomophila, we conducted food-choice experiments using two artificial diets differing in their relative protein to carbohydrate ratio. We show for the first time that cockroaches are able to self-select a protein-enriched diet as a response to bacterial infection. This is driven by a sharp decline in carbohydrate intake rather than an increase in protein intake. Additionally, infected cockroaches reduced their overall nutrient intake, which is consistent with an illness-induced anorexia-like response. The feeding pattern of bacteria-challenged individuals returned to normality approx 4 days after challenge. We also investigate whether cockroach survival and hemolymph immunity are enhanced in individuals when restricted to a protein-rich vs. carbohydrate-rich diet. Overall, our findings demonstrate that macronutrient preferences follow a general pattern independent of pathogen type. Furthermore, we show that interactions between nutrition and immunity are highly conserved in evolution, highlighted by the fact that caterpillars and cockroaches diverged some 386 million years ago.
The first analysis of environmental samples shows, that the use of TED-GC-MS is suitable to analyse microplastic in environmental samples. Compared to the micro-spectroscopic methods this method is faster and gives good hints to the occurrence of high loadings of MP in environmental samples. In consequence, the method allows the monitoring of the situation and the investigation of MP distribution pathways in environment, to assess the relevance of various inputs.
Genetic manipulation of protective pigments in a rock-inhabiting model fungus Knufia petricola A95
(2016)
Sub-aerial biofilms typically form on bare rock. They consist of 99% cell material and extracellular polymeric substances (EPS) metabolising at low water availability. Rock-inhabiting melanised fungi represent an important part of the microbial community in these environments, playing important roles in the colonisation of mineral surfaces, rock weathering and soil formation in the ecological/geochemical context. Different cellular stress responses make rock-inhabiting ascomycetes fit for survival under extremely changing irradiation, as well as water, energy sources and nutrient availability. Melanised, rock-inhabiting fungi possess multiple protective pigments, form facultative symbiotic associations with photobionts and weather minerals. Melanised fungi build a protective layer around the cell that is critical in adhesion to other living partners, for the colonisation of the substrate and in the subsequent damage of the colonised surface. We chose Knufia petricola (Chaetothyriales) as a model species to analyse colonisation of surfaces. The basic physiology of K. petricola strain A95 is studied, its full genome sequence has been prepared for annotation and methods for deleting specific genes have been established. Unique features of K. petricola including the protective pigments (melanin and carotenoids) and EPS/cell wall properties are now being dissected genetically. As K. petricola strain A95 is in the basic clade of Chaetothyriales, it is an ancestor of both important human pathogens including Exophiala and lichens from the Verrucariaceae family. For this reason studies with A95 can help clarify the basis of fungal pathogenicity – as well as explain interactions with microscopic phototrophic partners like unicellular green algae and cyanobacteria. With Knufia petricola we will establish a canon of experimental approaches to characterise and quantify fungi that actively contact inanimate solid materials. The set of methods developed for Knufia will be adapted to heavily melanised and EPS-producing ascomycetes and can be broadly applied to medically important as well as material-colonising fungi.
The presence of plastic debris and especially small plastic particles in marine ecosystems has been recognized in the 1970`s. Since then various other environmental systems all over the world, like rivers, lakes and biota have been found to be polluted by plastics. Lately, agriculturally used land, waste-water treatment and biogas facilities come into focus as possibly relevant distribution vectors. To monitor the situation and investigate distribution pathways, the need for fast and reliable analytical procedures is high.
Up to now, there is no standard procedure for sampling, concentrating and analyzing plastic particles in environmental samples. Our group recently reported the development of a new analyzing method for microscale plastic particles, thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS). This method consists of thermal extraction of the sample via thermogravimetric analysis, collection of the evolved gaseous decomposition products on a solid-phase adsorber and analysis of the loaded adsorber using Thermal-Desorption-GC-MS. This technique utilizes the characteristic decomposition products of polymers for identification and even quantification of plastics in environmental samples.
In the present work we investigated samples of fermentation residues taken from a biogas plant. The results of sample preparation, concentration and analysis are presented as well as a comparison with alternative methods.
Recovery of rare earth elements - optimized elemental analysis of fluorescent lamp shredder waste
(2016)
Rare earth elements (REE) are a crucial component of fluorescence lamps. Several procedures have been developed to recovery these technological important elements. Nevertheless, actual REE recycling from fluorescence lamps is scarce so far (recovery rate of less than 1 %), with current recycling approaches concentrating on glass recovery. Since most recycling processes include several, also wet-chemical steps, a complete knowledge of the actual elemental composition of the respective mass flows is necessary for an efficient REE recovery. We tested seven different reagent mixtures for microwave-assisted digestion of fluorescent lamp shredder, including HF, HClO4, and H2O2. We determined the concentrations of 25 of the most relevant rare earth and other trace elements in the respective dilutions. Two independent digestions, one a mixture of perchlorid/nitric/hydrofluoric acid and the other aqua regia, showed the highest concentrations of 23 of these elements, excluding only Sn and Tb. The REE concentrations in the tested lamp shredder sample (stated in g/kg) were 10.2 (Y), 12.1 (La), 7.77 (Ce), 6.91 (Eu), 1.90 (Gd), and 4.11 (Tb).
Populations of genetically identical cells that share the same environment can differ markedly in their phenotypes. This phenomenon has been termed phenotypic heterogeneity. While a few molecular mechanisms that lead to heterogeneity in gene expression have been elucidated, it remains unclear how heterogeneity in gene expression is transmitted to heterogeneity in activity; especially in metabolism. Metabolic activity of single bacterial cells can be quantified by labeling the substrate with stable isotopes and by measuring label uptake with nanometer-scale secondary ion mass spectrometry (NanoSIMS). Here we combined NanoSIMS with single-molecule mRNA fluorescence in situ hybridization (smFISH) to link heterogeneity in gene expression and metabolism in nitrogen fixing bacteria. We find that gene expression and metabolic activity are decoupled in single cells. However, heterogeneity in gene expression is correlated with heterogeneity in metabolic activity on the population level. Gene expression kinetics can provide insights into the molecular mechanisms that lead to heterogeneity in metabolism.
Populations of genetically identical cells that share the same environment can differ markedly in their phenotypes. This phenomenon has been termed phenotypic heterogeneity. While a few molecular mechanisms that lead to heterogeneity in gene expression have been elucidated, it remains unclear how heterogeneity in gene expression is transmitted to heterogeneity in activity; especially in metabolism. Metabolic activity of single bacterial cells can be quantified by labeling the substrate with stable isotopes and by measuring label uptake with nanometer-scale secondary ion mass spectrometry (NanoSIMS). Here we combined NanoSIMS with single-molecule mRNA fluorescence in situ hybridization (smFISH) to link heterogeneity in gene expression and metabolism in nitrogen fixing bacteria. We find that gene expression and metabolic activity are decoupled in single cells. However, heterogeneity in gene expression is correlated with heterogeneity in metabolic activity on the population level. Gene expression kinetics can provide insights into the molecular mechanisms that lead to heterogeneity in metabolism.
Recovery of rare earth elements - optimized elemental analysis of fluorescent lamp shredder waste
(2016)
Rare earth elements (REE) are a crucial component of fluorescence lamps. Several procedures have been developed to recovery these technological important elements. Nevertheless, actual REE recycling from fluorescence lamps is scarce so far (recovery rate of less than 1 %), with current recycling approaches concentrating on glass recovery. Since most recycling processes include several, also wet-chemical steps, a complete knowledge of the actual elemental composition of the respective mass flows is necessary for an efficient REE recovery. We tested seven different reagent mixtures for microwave-assisted digestion of fluorescent lamp shredder, including HF, HClO4, and H2O2. We determined the concentrations of 25 of the most relevant rare earth and other trace elements in the respective dilutions. Two independent digestions, one a mixture of perchlorid/nitric/hydrofluoric acid and the other aqua regia, showed the highest concentrations of 23 of these elements, excluding only Sn and Tb. The REE concentrations in the tested lamp shredder sample (stated in g/kg) were 10.2 (Y), 12.1 (La), 7.77 (Ce), 6.91 (Eu), 1.90 (Gd), and 4.11 (Tb).
Most microorganisms live in environments where nutrients are limited and fluctuate over time. Cells respond to nutrient fluctuations by sensing and adapting their physiological state. Recent studies suggest phenotypic heterogeneity in isogenic populations as an alternative strategy in fluctuating environments, where a subpopulation of cells express a function that allows growth under conditions that might arise in the future. It is unknown how environmental factors such as nutrient limitation shape phenotypic heterogeneity in metabolism and whether this allows cells to respond to nutrient fluctuations. Here, we show that substrate limitation increases phenotypic heterogeneity in metabolism, and this heterogeneity allows cells to cope with substrate fluctuations. We subjected the N2-fixing bacterium Klebsiella oxytoca to different levels of substrate limitation and substrate shifts, and obtained time-resolved single-cell measurements of metabolic activities using nanometre-scale secondary ion mass spectrometry (NanoSIMS). We found that the level of NH4+ limitation shapes phenotypic heterogeneity in N2 fixation. In turn, the N2 fixation rate of single cells during NH4+ limitation correlates positively with their growth rate after a shift to NH4+ depletion, experimentally demonstrating the benefit of heterogeneity. The results indicate that phenotypic heterogeneity is a general solution to two important ecological challenges - nutrient limitation and fluctuations - that many microorganisms face. Currently, we use NanoSIMS to develop a new approach that defines functionally-relevant, phenotypic biodiversity in microbial systems.
Phosphorus is essential for all animate beings and not replaceable in its functions. Recovered phosphorus from secondary sources is expected gain importance in the future due to supply risks and environmental concerns regarding fossil phosphate rock, the single source of phosphorus so far. Existing regulations, standards, and analytical methods are basically configured for well-established organic and mineral fertilizer but not for the emerging recycling products. Consequently, the respective procedures have to be adapted, especially in terms of matrix effects and so far not regulated pollutants like uranium and emerging pollutants of concern.
Industrial production of the cell protectant ectoine: protection mechanisms, processes, and products
(2014)
Bacteria, Archaea and Eukarya can adapt to Saline environments by accumulating compatible solutes in order to maintain an osmotic equilibrium. Compatible solutes are of diverse chemical structure (sugars, polyols, amino acid derivatives) and are beneficial for bacterial cells not only as osmoregulatory solutes, but also as protectants of proteins by mitigating detrimental effects of freezing, drying and high temperatures. The aspartate derivative ectoine is a wide spread compatible solute in Bacteria and possesses additional protective properties compared with other compatible solutes, and stabilizes even whole cells against stresses such as UV radiation or cytotoxins. The protective properties of ectoine for proteins can be explained by its strong (kosmotropic) interaction with water and subsequent exclusion from Protein surface, the decrease of the solubility of the peptide backbone and the strengthening of intramolecular hydrogen bonds (secondary structures). The stabilizing and UV-protective properties of ectoine attracted industry, which saw the potential to market ectoine as a novel active component in health care products and cosmetics. In joint efforts of industry and research large-scale fermentation procedures have been developed with the halophilic bacterium Halomonas elongata used as a producer strain. The two key technologies that allow for the annual production of ectoine on a scale of tons are the bacterial milking procedure and the development and application of ectoine-excreting mutants (“leaky” mutant). The details of these two procedures including the strain development and Fermentation processes will be introduced and current and future applications of ectoine will be discussed.
The formation of biofilms on different materials provokes high costs in industrial processes, as well as in medical applications. Therefore, the interest in development of new materials with improved surfaces to reduce bacterial colonization rises. In order to evaluate the quality and safety of these new materials, it is highly important to ensure world-wide comparable tests that are relying on statistical evidence. The only way to reach this statistical safety is through a high-throughput Screening under standardized test conditions.
We developed a flow through system for cultivation of biofilm-forming bacteria under controlled conditions with a total capacity for testing up to 32 samples in parallel. Quantification of the surface colonization was done by staining the bacterial cells with a fluorescence marker, followed by epifluorescence microscopy. More than 100 images of each sample were automatically taken and the surface coverage was estimated with the free open source software gmic (http://gmic.eu), followed by a precise statistical evaluation. Overview images of all gathered pictures of the whole material coupon were generated to illuminate the colonization characteristics of the selected bacteria on certain materials.
With this method, differences in bacterial colonization on different materials can be quantified in a statistically validated manner. The innovative and solid test procedure will support the design of improved materials for medical and industrial applications such as implants, ship hulls, pipelines, heat exchangers, aquaculture equipments, photovoltaic-panels and fundaments of wind power plants.
A new tool in material science - Targeted disruption of melanin synthesis in rock-inhabiting fungi
(2016)
The ability to survive almost absolute dehydration through air-drying is a remarkable feature of rock-inhabiting microcolonial fungi (MCF), which colonise rock surfaces in hot and cold deserts. Understanding of the underlying mechanisms which allow this group of fungi to conquer natural and man-made environments requires a set of modern biological techniques and approaches that are under development in our laboratory. We will present an overview of the targeted disruption of melanin biosynthesis genes in the rock-inhabiting Knufia petricola and give inside into the lines of research and the network of supporting laboratories that made this progress possible.
A new tool in material science - Targeted disruption of melanin synthesis in rock-inhabiting fungi
(2016)
The ability to survive almost absolute dehydration through air-drying is a remarkable feature of rock-inhabiting microcolonial fungi (MCF), which colonise rock surfaces in hot and cold deserts. Understanding of the underlying mechanisms which allow this group of fungi to conquer natural and man-made environments requires a set of modern biological techniques and approaches that are under development in our laboratory. We will present an overview of the targeted disruption of melanin biosynthesis genes in the rock-inhabiting Knufia petricola and give inside into the lines of research and the network of supporting laboratories that made this progress possible.
Sewage sludge has one of the highest phosphorus (P) potentials of all waste materials. Therefore, P-recycling from sewage sludge could contribute to close the P-cycle. Recently, various processes for P-recovery have been developed, but most of them were not established in industrial scale due to their poor economic feasibility. In the present study, two common methods (low-temperature conversion at 400-500°C and thermochemical treatment at 950-1000°C were investigated and combined to produce highly bioavailable P-fertilizers from two different types of sewage sludge based on chemical phosphorus precipitation with FeCl2 and enhanced biological phosphorus removal.
The halophilic bacterium Halomonas elongata takes up the compatible solute ectoine via the osmoregulated TRAP transporter TeaABC. A fourth orf (teaD) is located adjacent to the teaABC locus that encodes a putative universal stress protein (USP). By RT-PCR experiments we proved a cotranscription of teaD along with teaABC. Deletion of teaD resulted in an enhanced uptake for ectoine by the Transporter TeaABC and hence a negative activity regulation of TeaABC by TeaD. Atranscriptional regulation viaDNA binding could be excluded. ATP binding to native TeaD was shown by HPLC, and the Crystal structure of TeaD was solved in complex with ATP to a resolution of 1.9 A ° by molecular replacement. TeaD forms a dimer-dimer complex with one ATP molecule bound to each monomer, which has a Rossmann-like R/β overall fold. Our results reveal an ATP-dependent oligomerization of TeaD, which might have a functional role in the regulatory mechanism of TeaD. USP-encoding orfs, which are located adjacent to genes Encoding for TeaABC homologues, could be identified in several other organisms, and their physiological role in balancing the internal cellular ectoine pool is discussed.
Numerous membrane importers rely on accessory water-soluble proteins to capture their substrates. These substrate-binding Proteins (SBP) have a strong affinity for their ligands; yet, Substrate release onto the low-affinity membrane transporter must occur for uptake to proceed. It is generally accepted that release is facilitated by the association of SBP and transporter, upon which the SBP adopts a conformation similar to the unliganded state, whose affinity is sufficiently reduced. Despite the appeal of this mechanism, however, direct supporting evidence is lacking. Here, we use experimental and theoretical methods to demonstrate that an allosteric mechanism of enhanced substrate release is indeed plausible.
First, we report the atomic-resolution structure of APO TeaA, the SBP of the Na!-coupled ectoine TRAP transporter TeaBC from Halomonas elongata DSM2581T, and compare it with the substrate-bound structure previously reported. Conformational freeenergy landscape calculations based upon molecular Dynamics simulations are then used to dissect the mechanism that couples ectoine binding to structural change in TeaA. These insights allow us to design a triple mutation that biases TeaA toward apo-like conformations without directly perturbing the binding cleft, thus mimicking the influence of the membrane transporter. Calorimetric measurements demonstrate that the ectoine affinity of the conformationally biased triple mutant is 100-fold weaker than that of the wild type. By contrast, a control mutant predicted to be conformationally unbiased displays wild-type affinity. This work thus demonstrates that substrate release from SBPs onto their Membrane transporters can be facilitated by the latter through a mechanism of allosteric modulation of the former.
Compared to the designated European upper reference level of 300 Bq/m³ for indoor radon concentrations, the contribution of building materials appears to be low. Taking into account the recommended limit of 100 Bq/m³ by WHO as well as the increased dose conversion factor, the contribution of building products is quite relevant, especially at low air change rates. Therefore in Germany a maximum contribution of building materials to the indoor radon concentration of 20 Bq/m³ is discussed.
Because measurements of low concentrations are associated with high uncertainties, radon exhalation rates are often determined in chambers without air exchange and indoor conditions are extrapolated.
This study investigated the suitability of direct low level radon measurement under simulated indoor conditions with commercially available instruments, based on the preliminary EU standard for the determination of the emission of volatile organic compounds (VOC) from building materials in test chambers.
Measurements are possible with a relative uncertainty ranging from 7 to 18%. Four major problems were identified:
1. Detector sensitivity: Two of four instruments were identified to determine low radon concentrations in a sufficiently short measuring time.
2. Thoron discrimination: Thoron was discriminated by aging the sampled air in a hose before the detector.
3. Sampling setup: An external chamber measurement was feasible as long as all main system parts were under slight overpressure.
4. Blank value: For VOC-emission testing ambient air, conditioned by filtration and sorption, is used to generate an air exchange. Regarding radon, this treatment is non-effective. If all instrument background levels have been characterized, the blank value must be measured with a second detector in parallel.