4 Material und Umwelt
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Traceable and reliable chemical element analysis of aerosols by X-ray spectrometry was investigated using aerosol samples from field campaigns which have been measured in the GIXRF-beamline at BESSY.
The reference-free XRF approach allows for a traceable analysis of the mass deposition.
Traceable quantification by means of XRF can be transfered to benchtop instrumentation used in the laboratory Chemical and dimensional analysis of deposited aerosol allows for a comprehensive analysis of aerosols, e.g. for toxicity assessment and determination of the source The folowing elements could be identified and quantified in the field samples: Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, W, Pb.
Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). Within the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling was combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution of only a few hours and with good size resolution in the PM10 range. A proof of principles of this methodological approach and the comparison to standard methods within the scope of a field campaign will be presented. Secondly, aerosol sampling and TXRF analysis seems suitable for the quantification of elements in indoor aerosols as well and may provide an important enhancement of existing methods for the analysis of organic species in aerosols (such as sampling and TD-GC/MS). As an example, the TXRF analysis of particles emitted from laser printers under controlled conditions in an environmental test chamber will be presented.
Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden.
Recent studies have shown that host-microbiota interactions can lead to dramatic changes in host phenotype especially behaviour. We investigate the causal drivers of microbe-associated shifts in host phenotype by examining how feeding behaviour is modulated by a bacterial infection in an omnivorous cockroach: Blatta orientalis. We conducted food-choice experiments after challenging hosts with the common entomopathogenic soil bacterium Pseudomonas entomophila to understand the impact of bacterial pathogens on host macronutrient preference. We find that immune challenge by this bacterium drives a sharp decline in carbohydrate intake and results in a relative increase in the ratio of protein to carbohydrate consumed. Additionally, infected cockroaches reduce their overall nutrient intake. We show for the first time that cockroach feeding behaviour is dynamically modulated by a pathogen. In contrast to studies on Spodoptera moths, this modulation does not impact any of the immune parameters we measured: it does not affect the abundance of immune related proteins in the hemolymph, hemolymph antimicrobial activity, or survival. This leads to the possibility that as long-lived omnivorous species B. orientalis may be better adapted to unpredictable variation in food availability and quality. An illness-induced anorexia-like response which is thought to assist hosts in limiting nutritional resources available to pathogens is therefore the most likely cause of the observed phenotype. Reduction of carbohydrate intake by sick individuals would be consistent with such an explanation.
In another cockroach species Blatella germanica we also investigate whether in addition to pathogens, host microbiota especially gut commensals are causally responsible for shifts in host behavioural phenotype and immune competence. To address this, we conduct food-choice and immunechallenge experiments in germ-free cockroaches and naïve cockroaches.
Human-made systems, also called “build environment” or “technosphere”, sustain human comfort as well as our industrial activities. These systems have become particularly widespread since the Industrial Revolution, i.e., since the 17th century. At the same time, these technical systems – buildings, monuments, energy production, transformation and transmission, water purification and supply systems - serve as new habitats for living organisms.
Life is ubiquitously present on our planet since a very long time: the Earth is 4.54 billion years old and microbial communities have played a key role on our planet for 3.7 billion years. Once human-made system appeared, microorganisms became an integral part of all types of technosphere infrastructure as well.
Here we will illustrate biosphere-technosphere interactions using a specific example of the black fungi and their impact on the efficiency of solar (photovoltaic) panels. This expanding renewable infrastructure for electricity generation is growing on all continents - and create a specific, arid habitat for stress-tolerant black fungi.
Black fungi were once discovered in hot and cold natural deserts – and now belong to the persistent colonisers of human-made deserts of solar parks. This new niche is evolving an impressive biodiversity. So far more than 60 isolates of black fungi belonging to Arthoniomycetes, Eurotiomycetes and Dothideomycetes were obtained from solar panels in Europe and Americas. Here we will present the analysis of this emerging anthropogenic biodiversity.
Opportunities for future research in the field include quantification of the microbial load on technosphere surfaces – along with characterisation of the corresponding microbial diversity. The strategy of precise measurement and characterisation will enable us to reliably determine the beneficial and harmful functions that living microorganisms play in the functioning of energy-generating systems – and technosphere in general.
Microbial contamination of fuels by fungi or bacteria poses risks such as corrosion and fuel system fouling, which can lead to critical problems in refineries and distribution systems and has a significant economic impact at every stage of the process. Many factors have been cited as being responsible for microbial growth, like the presence of water in the storage tanks. In fact, only 1 % water in a storage system is sufficient for the growth of microorganisms like bacteria or yeasts, as well as for the development of fungal biomass at the oil/water interface.
This work presents a rapid test for the accurate determination of genomic DNA from aqueous fuel extracts. The detection is based on the use of polystyrene-mesoporous silica core-shell particles onto which modified fluorescent molecular beacons are covalently grafted. These beacons contain in the hairpin loop a target sequence highly conserved in all bacteria, corresponding to a fragment of the 16S ribosomal RNA subunit. The designed single-stranded molecular beacon contained fluorescein as an internal indicator and a quencher in its proximity when not hybridized. Upon hybridization in presence of the target sequence, the indicator and the quencher are spatially separated, resulting in fluorescence enhancement. To perform the assay the developed particles were deposited on different glass fibre strips to obtain a portable and sensitive rapid test. The assays showed that the presence of genomic DNA extracts from bacteria down to 50–70 μg L–1 induced a fluorescence response. The optical read-out was adapted for on-site monitoring by fitting a 3D-printed case to a conventional smartphone, taking advantages of the sensitivity of the CMOS detector. Such embedded assembly enabled the detection of genomic DNA in aqueous extracts down to the mg L–1 range and represents an interesting step toward on-site monitoring of fuel contamination.
Technical advances in the study of molecular evolution have crystallized the fundamental insight that many bee pathogens evolve and adapt over timescales that overlap with host ecology. At the same time, the role played by bee host community ecology is increasingly being appreciated in host-parasite interactions. Here, we focus on Deformed wing virus (DWV) and present recent studies exploring the link between virulence, DWV genetic diversity and changes to host ecology - namely the arrival of an invasive ectoparasite, the Varroa destructor mite, which vectors viruses between honeybees. Specifically, we show how V. destructor may have created conditions for the emergence of more virulent strains of DWV in the western honeybee, Apis mellifera. We present a molecule-to-ecology framework to help interpret findings and to guide future hypotheses, emphasizing the role of molecular interactions between viruses and host immunity as drivers of change at the bee population level.
Environmental sustainability and –stability of Materials concerning the Migration of pollutants
(2018)
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long-term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer-based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.
Bee populations have declined significantly in recent years and this is thought to be attributable at least in part to the (re-)emergence of viruses. These viruses are predominantly positive single stranded (+ss) RNA viruses belonging to the Picornavirales. Managed honeybees are often infested with the invasive mite, Varroa destructor, which vectors RNA viruses including Deformed wing virus (DWV, family Iflaviridae): a leading culprit of colony losses. Many bee viruses have been sequenced and structural features are now available for viruses such as DWV. DWV consists of at least 3 distinct genotypes, two of which have been shown to be differentially virulent in honeybees. Molecular studies have demonstrated that DWV has a mean evolutionary rate of 1.35 x 10-3 per site per year. For such viruses – in contrast to their eukaryotic hosts – ecological and evolutionary timescales significantly overlap. This rapid evolution allows RNA viruses to adapt quickly to novel host environments with recombination representing an additional key source of genetic variation. Interestingly, recombination between genotypes of DWV has recently been shown to be a common occurrence in honeybees. A challenge has been to develop bioinformatics tools that can accurately reconstruct viral haplotypes – including recombinants – from heterogenous high-throughput sequence data.
The impact of blood-to-blood Varroa destructor transmission on virus evolution represents an important question in bee virus research. Due to the nature of the V. destructor life cycle, predictions can be made about the potential impact of the mite on virus virulence evolution. Specifically, the developing honeybee host pupa should remain alive until close to the completion of metamorphosis to provide sufficient time for successful mite reproduction, including offspring mating. For optimal transmission, any virus found in a mature and mated daughter mite will hold a significant selective advantage over a virus found in an immature or unmated daughter mite – placing a cost on virus virulence that impacts honeybee pupae before mites can mate. On the other side, viruses replicating too slowly and with delayed virulence effects will hold a selective handicap because fewer transmission units will be found in mated mites. I have hypothesized that the evolution of virus virulence shifted following the arrival of V. destructor, with viruses, including recombinants and/or specific viral genotypes being selected for a level of virulence in pupae (and likely also in adults) that maximises R0, which represents the basic reproductive number of the virus in the host population. R0 is defined by the number of subsequent infections caused by a single infection and it must be greater than 1 for an infection to spread in a population. It is enhanced by maximising the number of transmission units passed to uninfected susceptible vectors, and ultimately hosts (Figure 1).
Honeybee viruses are also shared with sympatric wild bees and viral prevalence and sequence data indicate frequent virus transmission between managed and wild bee species. In addition to infecting the western honeybee (Apis mellifera), DWV can infect other Asian honeybee species such as Apis ceranae. Outside of honeybees, DWV has been found widely in bumblebees, including solitary bees and wasps and there is evidence that it can actively replicate in several Bombus and solitary bee species. Whether the arrival of the V. destructor mite in A. mellifera has driven viral emergence in non-Apis bees is a target of ongoing research.
Our understanding of RNA viruses from edible insects is minimal at best, with studies largely focusing on model insect species and those associated with obvious signs of disease. This represents a considerable gap in understanding, given the growing role of insects as a source of food and feed, as well as the more general relevance of insects in agriculture and health. Illness due to entomophagy is rare but well documented, including fatal cases following the consumption of termites. Termites are eaten commonly in tropical Asia, Africa and South America, and are among the insects with the highest recorded fat content. There are many species of termites, with a wide range of diets and habitats centering around the consumption of wood and soil substrates. In this study, we report the results from a survey of more than 30 cockroach and termite transcriptomes, with the aim of understanding the diversity and evolution of RNA viruses as well as other potentially pathogenic organisms that are associated with this relevant but somewhat overlooked group of insects. We discuss our results in the context of the possible zoonotic risk posed by insects, as well as in the context of emerging viral and other disease threats that may face insects being reared at industrial scales.