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Bioinformatics meets virology: The European virus bioinformatics center's second annual meeting
(2018)
The Second Annual Meeting of the European Virus Bioinformatics Center (EVBC), held in Utrecht, Netherlands, focused on computational approaches in virology, with topics including (but not limited to) virus discovery, diagnostics, (meta-)genomics, modeling, epidemiology, molecular structure, evolution, and viral ecology. The goals of the Second Annual Meeting were threefold: (i) to bring together virologists and bioinformaticians from across the academic, industrial, professional, and training sectors to share best practice; (ii) to provide a meaningful and interactive scientific environment to promote discussion and collaboration between students, postdoctoral fellows, and both new and established investigators; (iii) to inspire and suggest new research directions and questions. Approximately 120 researchers from around the world attended the Second Annual Meeting of the EVBC this year, including 15 renowned international speakers. This report presents an overview of new developments and novel research findings that emerged during the meeting.
Unity in defence: honeybee workers exhibit conserved molecular responses to diverse pathogens
(2017)
Background: Organisms typically face infection by diverse pathogens, and hosts are thought to have developed specific responses to each type of pathogen they encounter. The advent of transcriptomics now makes it possible to test this hypothesis and compare host gene expression responses to multiple pathogens at a genome-wide scale. Here, we performed a meta-analysis of multiple published and new transcriptomes using a newly developed bioinformatics approach that filters genes based on their expression profile across datasets. Thereby, we identified common and unique molecular responses of a model host species, the honey bee (Apis mellifera), to its major pathogens and parasites: the Microsporidia Nosema apis and Nosema ceranae, RNA viruses, and the ectoparasitic mite Varroa destructor, which transmits viruses.
Results: We identified a common suite of genes and conserved molecular pathways that respond to all investigated pathogens, a result that suggests a commonality in response mechanisms to diverse pathogens. We found that genes differentially expressed after infection exhibit a higher evolutionary rate than non-differentially expressed genes. Using our new bioinformatics approach, we unveiled additional pathogen-specific responses of honey bees; we found that apoptosis appeared to be an important response following microsporidian infection, while genes from the immune signalling pathways, Toll and Imd, were differentially expressed after Varroa/virus infection. Finally, we applied our bioinformatics approach and generated a gene co-expression network to identify highly connected (hub) genes that may represent important mediators and regulators of anti-pathogen responses.
Conclusions: Our meta-analysis generated a comprehensive overview of the host metabolic and other biological processes that mediate interactions between insects and their pathogens. We identified key host genes and pathways that respond to phylogenetically diverse pathogens, representing an important source for future functional studies as well as offering new routes to identify or generate pathogen resilient honey bee stocks. The statistical and bioinformatics approaches that were developed for this study are broadly applicable to synthesize information across transcriptomic datasets. These approaches will likely have utility in addressing a variety of biological questions.
Technetium- and Rhenium-Labelled Fatty Acids as Model Compounds for Myocardial Metabolism Imaging
(2002)
In an attempt to develop new technetium-based radiopharmaceuticals for the non-invasive diagnosis of oxidative myocardial metabolism, rhenium model compounds according to the 3+1' mixed ligand approach as well as the organometallic tricarbonyl-design were synthesized. The geometrical impact of different chelates on the integrity of the fatty acid head structure was determined by single crystal X-ray analyses. To evaluate the diagnostic potential of the analogous Technetium-99m compounds, fatty acid complexes of the 3+1' mixed ligand type were prepared on n.c.a.-level and studied in the isolated constant-flow-perfused guinea pig heart model; compared to established [123I]Iodine-labelled fatty acid radiotracers, the tested Technetium-99m derivatives showed a specific, however significantly lower myocardial extraction rate.
Background: Host–pathogen interactions can lead to dramatic changes in host feeding behaviour. One aspect of this includes self-medication, where infected individuals consume substances such as toxins or alter their macronutrient consumption to enhance immune competence. Another widely adopted animal response to infection is illness-induced anorexia, which is thought to assist host immunity directly or by limiting the nutritional resources available to pathogens. Here, we recorded macronutrient preferences of the global pest cockroach, Blatta orientalis to investigate how shifts in host macronutrient dietary preference and quantity of carbohydrate (C) and protein (P) interact with immunity following bacterial infection.
Results: We fnd that B. orientalis avoids diets enriched for P under normal conditions, and that high P diets reduce cockroach survival in the long term. However, following bacterial challenge, cockroaches signifcantly reduced their overall nutrient intake, particularly of carbohydrates, and increased the relative ratio of protein (P:C) consumed. Surprisingly, these behavioural shifts had a limited efect on cockroach immunity and survival, with minor changes to immune protein abundance and antimicrobial activity between individuals placed on diferent diets, regardless of infection status.
Conclusions: We show that cockroach feeding behaviour can be modulated by a pathogen, resulting in an illness-induced anorexia-like feeding response and a shift from a C-enriched to a more P:C equal diet. However, our results also indicate that such responses do not provide signifcant immune protection in B. orientalis, suggesting that the host’s dietary shift might also result from random rather than directed behaviour. The lack of an apparent beneft of the shift in feeding behaviour highlights a possible reduced importance of diet in immune regulation in these invasive animals, although further investigations employing pathogens with alternative infection strategies are warranted.
Synthesis of Li ion battery materials via ball milling has been a huge area of growth, leading to new high-capacity electrode materials, such as a number of promising disordered rocksalt (DRS) phases. In prior work, it was generally assumed that the synthesis was facilitated simply by local heating effects during the milling process. In this work, we show that ball milling Li2MoO4 leads to a phase transformation to the high pressure spinel polymorph and we report electrochemical data for this phase. This observation of the formation of a high pressure polymorph shows that local heating effects alone cannot explain the phase transformation observed (phenakite to spinel) and so indicates the importance of other effects. In particular, we propose that when the milling balls collide with the material, the resulting shockwaves exert a localised pressure effect, in addition to local heating. To provide further support for this, we additionally report ball milling results for a number of case studies (Li2MnO3, Li2SnO3, Nb2O5) which reinforces the conclusion that local heating alone cannot explain the phase transformations observed. The work presented thus provides greater fundamental understanding of milling as a synthetic pathway and suggests potential strategies to prepare such samples without milling (e.g., doping to create internal chemical pressure). In addition, we suggest that further research is needed into the effect of the use of milling as a route to smaller particles, since we believe that such milling may also be affecting the surface structure of the particles through the influence of the shockwaves generated.
Honeybee symbionts, predominantly bacteria, play important roles in honeybee health, nutrition, and pathogen protection, thereby supporting colony health. On the other hand, fungi are often considered indicators of poor bee health, and honeybee microbiome studies generally exclude fungi and yeasts. We hypothesized that yeasts may be an important aspect of early honeybee biology, and if yeasts provide a mutual benefit to their hosts, then honeybees could provide a refuge during metamorphosis to ensure the presence of yeasts at emergence. We surveyed for yeast and fungi during pupal development and metamorphosis in worker bees using fungal-specific quantitative polymerase chain reaction (qPCR), next-generation sequencing, and standard microbiological culturing. On the basis of yeast presence in three distinct apiaries and multiple developmental stages, we conclude that yeasts can survive through metamorphosis and in naïve worker bees, albeit at relatively low levels. In comparison, known bacterial mutualists, like Gilliamella and Snodgrassella, were generally not found in pre-eclosed adult bees. Whether yeasts are actively retained as an important part of the bee microbiota or are passively propagating in the colony remains unknown. Our demonstration of the constancy of yeasts throughout development provides a framework to further understand the honeybee microbiota.
Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2-hydroxyethyl)terephthalate (BHET) in refluxing 1,2-dichlorobenzene. Second, the same monomers were polycondensed at 0-20 °C in the presence of pyridine. Third, dicarboxylic acid dichlorides and silylated BHET were polycondensed in bulk. Only this third method gave satisfactory molecular weights. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that the copolyesters prepared by the pyridine and silyl methods might have contained considerable fractions of cyclic oligoesters and polyesters despite the absence of transesterification and backbiting processes. The alternating sequences and thermal properties were characterized with 1H NMR spectroscopy and differential scanning calorimetry measurements, respectively. In agreement with the alternating sequence, all copolyesters proved to be crystalline, but the crystallization was extremely slow [slower than that of poly(ethylene terephthalate)]. A second series of alternating copolyesters was prepared by the polycondensation of silylated bis(4-hydroxybut- yl)terephthalate with various aliphatic dicarboxylic acid dichlorides. The resulting copolyesters showed significantly higher rates of crystallization, and the melting temperatures were higher than those of the BHET-based copolyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3371-3382, 2001
Es wird ein Großversuch beschrieben, in dem der Nachweis erbracht wird, dass Klärschlammasche, die einen hohen Anteil an P und Fe aufweist, in der Metallurgie als Rohstoffkomponente für Roheisen mit einem erhöhten Phosphorgehalt eingesetzt werden kann. Der zunächst mit ca. 100 t Klärschlammasche hergestellte Sinter ließ sich ähnlich dem konventionell hergestellten Sinter im Hochofen zu Roheisen verarbeiten. Roheisen mit erhöhtem Phosphoranteil wird für die Herstellung von filigranen und dünnwandigen Gußstücken verwendet.
Novel technetium(III) mixed-ligand chelates for the design of lipophilic complexes stable in vivo
(2001)
Experimentelle Bestimmung des Inert- und Brenngaseinflusses auf die Stabilitätsgrenzdrücke von Ethin
(2003)
In the field of water pipelines, geothermal energy production as well as carbon capture and storage technology (CCS) materials have to provide a high resistance to corrosion and mechanical stress. The combination of cyclic load and corrosive aqueous environment leads to corrosion fatigue of pipes and components (e.g. pumps) and thus inevitably to the reduction of the lifetime of these components. To estimate the reliability of components from adjusted in-situ-laboratory experiments a corrosion chamber was designed and tested with CO2 saturated corrosive aqueous media flowing at a steady rate. Unique feature of this special chamber is its installation directly onto the sample and thus providing flexible usability in almost every testing machine. This allows simultaneous mechanical loading of the sample, operation at temperatures up to 100 °C and exposure to fluid flow of corrosive liquids and gases. The lifetime reduction of AISI 420C (X46Cr13, 1.4034) is demonstrated at T=60 °C, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO2. S-N plots, micrographic-, phase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion fatigue behavior. Maximum number of cycles (here 12.5 x 106 cycles to failure) is reached at σa =173 MPa. No typical fatigue strength exists and passive corrosion fatigue may be identified as failure cause.
The lifetime reduction of cyclically loaded AISI 420C (X46Cr13, 1.4034) constantly exposed to highly corrosive CO2-saturated hot thermal water is demonstrated in in situ-laboratory experiments (60 °C, brine: Stuttgart Aquifer, flowing CO2: 30 L/h). SN plots, micrographic-, phase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion and corrosion fatigue behavior. Maximum number of cycles (here 12.5 × 106 cycles to failure) is reached at σa = 173 MPa. Hydroxide and siderite layers were found on pits and crack surfaces. No typical fatigue limit exists and pit corrosion prior to crack initiation may be identified as failure cause.
In einem Gemeinschaftsprojekt der Stahl- und Automobilindustrie wurden an zwanzig Stählen für Feinblech elastische, plastische und zyklische Kennwerte für die FE-Simulation ermittelt. Die Untersuchungen mit dem Ziel, Eingabekennwerte für FE-Berechnungen zu erhalten, erbrachten einen erheblichen Erfahrungszuwachs im Bereich der Messtechnik sowie der Datenerfassung und -weiterverarbeitung. Der vorliegende Beitrag gibt einen Überblick über die Untersuchung und ihre Ergebnisse.
The paper gives a survey of the Soviet (Russian) -German activities which started in 1988 with the objective of creating a long-term scientific-technical cooperation in the field of transport and storage casks for spent nuclear fuel. The first step, i.e., the step of informing each other about the state of development is done. The more complicated second phase with concerted common activities of both the Russian and German competent authorities and industrial enterprises is intended to start in the near future.
Ziel des Forschungsvorhabens ist es, ein standardisiertes Prüf- und Bewertungsverfahren zur Bestimmung des Beitrags reaktiver Brandschutzsysteme (RBS) zum Feuerwiderstand von Stahlzuggliedern zu erarbeiten und dieses in ein Entwurfsdokument für eine europäische Prüfnorm zu überführen. Hierzu wurden einerseits bereits vorhandene Erfahrungen und Erkenntnisse genutzt und andererseits mittels Brandversuchen neue Prüfdaten zur Beantwortung bisher offengebliebener Aspekte zum Einfluss der Bauteilorientierung und Profilart erzeugt und ausgewertet. Dadurch wird die prüftechnische Grundlage für eine sichere, zulassungsbasierte Anwendung von reaktiven Brandschutzsystemen auf zugbeanspruchten Stahlbauteilen gelegt und ein einheitliches Sicherheitsniveau etabliert.
Der im Rahmen des Forschungsprojektes entwickelte Normentwurf wurde mit den Fachexperten der zuständigen nationalen und europäischen Normungsgremien diskutiert und abgestimmt. Das erarbeitete Prüf- und Auswertungsverfahren basiert auf der Durchführung von Brandversuchen an mechanisch belasteten Stahlzuggliedern mit RBS. Ergänzend sind unbelastete Brandversuche zur Beurteilung des Einflusses der Bauteilorientierung sowie der Eignung bei Schwelbrandbeanspruchung möglich. Die im Projekt durchgeführten experimentellen Untersuchungen liefern die Grundlage für den im Normenentwurf vorgeschlagenen Prüfaufbau der mechanisch belasteten und unbelasteten Brandversuche. Ferner konnte durch die Untersuchungen gezeigt werden, dass sich unter bestimmten Voraussetzungen die Prüfergebnisse von Stahlzuggliedern mit Kreisvollprofil ohne zusätzliche Brandversuche auf entsprechende Zugglieder mit Rechteckvollprofil übertragen lassen. Darüber hinaus konnte belegt werden, dass die Leistungsfähigkeit eines RBS aufgrund unterschiedlicher Bauteilorientierungen abnehmen kann und daher zwingend beim Anwendungsbereich des RBS zu berücksichtigen ist. Hierzu wird ein Temperaturdifferenz-kriterium vorgeschlagen, bei dessen Einhaltung die Wirksamkeit des RBS bei von der horizontalen Referenzorientierung abweichenden Bauteilneigungen noch gleichwertig gegeben ist. Andernfalls bietet der Normenentwurf die Möglichkeit die reduzierte thermische Schutzwirkung des RBS im Assessment zu berücksichtigen.
Die Ergebnisse aus dem Forschungsvorhaben wurden bereits auf einem wissenschaftlichen Symposium vorgestellt sowie in einer referierten Fachzeitschrift publiziert. Ferner wurden die Informationen zum Forschungsprojekt und dem Normenentwurf im Rahmen eines Anwenderworkshops interessierten Kreisen zugänglich gemacht. Der im Projekt ausgearbeitete Normenentwurf wird dem zuständigen europäischen Normungsgremien, CEN/TC 127/WG 1, zur Verfügung gestellt und dort zur Abstimmung gestellt.
"Ullmann's Encyclopedia of Industrial Chemistry" is the benchmark reference in chemistry and chemical and life science engineering, covering inorganic and organic chemicals, advanced materials, pharmaceuticals, polymers and plastics, metals and alloys, biotechnology and biotechnological products, food chemistry, process engineering and unit operations, analytical methods, environmental protection, and much more.
The present article is part of the topic collection "Environmental Protection and Industrial Safety". It covers plant and process safety, focusing on hazardous materials and process conditions.
Infections with multi-resistant Gram negative pathogens are a major threat to our health system. In order to serve the needs in antibiotics development we selected untapped bioresources and implemented high throughput approaches suitable for the discovery of strains producing antibiotics with anti-Gram negative activity.
Our approaches rely on the hypothesis that Termite associated bacteria are likely to produce potent antibiotics to defend their hosts against entomopathogenic microorganisms. Termite nests and guts harbor suitable, highly diverse microbiomes in which bacterial taxa are present known to potentially produce natural compounds. In
a first step the diversity of Coptotermes species nest microbiomes was assessed carefully by using 16S rDNA amplicon sequencing on the Illumina MiSeq platform and nest material was selected to retrieve viable cells by using Nycodenz density gradient centrifugation. In order to analyze the diversity of the culturable termite nest microbiome, bacterial cells were either distributed in 384-well plates
(approach 1) or encapsulated in small spheric agarose beads by an high throughput microfluidics technique (approach 2). Cultures obtained from approach 1 were scaled-up in 96-well Duetz-systems for characterization of diversity and for rapid supernatant screening using the bioluminescence-labeled E. coli pFU166. The generated
droplets of approach 2 simultaneously received a small population of GFP-tagged Gram negative screening cells and were sorted for low fluorescence using FACS. After elimination of redundancy we performed a fast scale-up of active strains.
Implementation of this pipeline allows us to prioritize antibiotics producing strains in a ultra-high throughput fashion and by cultivation of broad diversity in our approches.
Termitidae comprises 80% of all termite species that play dominant decomposer roles in Tropical cosystems. Two major events during Termite evolution were the loss of cellulolytic gut protozoans in the ancestor of Termitidae and the subsequent gain in the termitid subfamily Macrotermitinae of fungal symbionts cultivated externally in ‘‘combs’’ constructed within the nest. How these symbiotic transitions occurred remains unresolved. Phylogenetic analyses of mitochondrial data previously suggested that Macrotermitinae is the earliest branching termitid lineage, followed soon after by Sphaerotermitinae, which cultivates bacterial symbionts on combs inside its nests. This has led to the hypothesis that comb building was an important evolutionary step in the loss of gut protozoa in ancestral termitids. We sequenced genomes and transcriptomes of 55 termite species and reconstructed phylogenetic trees from up to 4,065 orthologous genes of 68 species. We found strong support for a novel sister-group relationship between the bacterial comb-building Sphaerotermitinae and fungus comb-building Macrotermitinae.
This key finding indicates that comb building is a derived trait within Termitidae and that the creation of a comb-like ‘‘external rumen’’ involving bacteria or fungi may not have driven the loss of protozoa from ancestral termitids, as previously hypothesized.
Instead, associations with gut prokaryotic symbionts, combined with dietary shifts from wood to other plant-based substrates, may have played a more important role in this symbiotic transition. Our phylogenetic tree provides a platform for future studies of comparative termite evolution and the evolution of symbiosis in this taxon.
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.
In geothermal power plants materials e.g. pumps are exposed to extremely corrosive thermal water. This results in corrosion fatigue and so inevitably the reduction of the lifetime of these components. Also in the field of the carbon dioxide storage technology (carbon capture and storage CCS) components are exposed to a corrosive environment and mechanical stress. In order to gain knowledge upon the corrosion fatigue strength of materials a corrosion chamber for "in situ" conditions was designed and successfully applied.Two different steels X46Cr13 and X5CrNiCuNb16-4 have been tested and their corrosion fatigue behavior was compared. To simulate the frequency of operating pumps (30 – 40 Hz) a resonant testing machine was used. In addition technical CO2 was introduced into the closed system at a rate close to 9 L/h to keep stable environmental conditions. The samples have a surface roughness of Rz = 4 to simulate technical machined surfaces. The calculated tensile strength of X46Cr13 with soft annealed microstructure (coagulated cementite in ferrite-perlite matrix) is about 680 MPa and the yield strength is about 345 MPa. The tensile strength of X5CrNiCuNb16-4 is about 1078 MPa and the yield strength about 928 MPa. Testing parameters are: corrosion media: saline aquifer water (Stuttgart Aquifer) temperature of the brine at 60 °C and load ratio of R=-1. For X46Cr13 a stress amplitude between 160 MPa to 270 MPa and for X5CrNiCuNb16-4 a stress amplitude between 150 to 500 was chosen. Cycles until crack initiation differ strongly and were found to start at 5 x 104 up to 12.5 x 106 cycles.X46Cr13 has reached a maximum number of cycles (12.5 x 106) at a stress amplitude of 173 MPa. X5CrNiCuNb16-4 has reached the maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa. The range of scatter for X5CrNiCuNb16-4 is very high (1:34) in comparison the range of scatter for X46Cr13 (1:3.5).
Design of a high pressure system for in-situ tests on the corrosion fatigue of metallic materials
(2014)
In geothermal power plants pumps are exposed to corrosive and oscillating loads. This leads to corrosion fatigue and reduces the lifetime of certain components. Usually underwater power pumps are placed inside the borehole. In this case an installation depth of 600 to 800 meters below ground level is typical. In these depths an additional load due to high pressure and high temperature is introduced which is based on geothermal brine. Therefore the material which is used for the pump is steel.For fatigue testing at loads existing in deep geological layers an appropriate system for fatigue tests under in-situ conditions was set up. The requirements of the design are: temperature of the corrosion medium of 200 °C pressure of 200 bars and the complete immersion of the specimen in flowing corrosion medium containing mixtures of corrosive gasses during the entire test period.The test system has three main components the corrosion chamber the heating module and the reservoir. It is important that the corrosion chamber is only fixed onto the specimen which allows for highest flexibility of the test system operational in many different test machines. The heating module heats the corrosion medium up to 200 °C. The reservoir make sure that the volume of the corrosion medium satisfies requirements of the DIN 50905 Part 1 is conformed providing minimum required corrosive medium of 10 ml/cm² in relation to the sample surface.This innovative fatigue test system aims at performing in- situ fatigue corrosion tests simultaneously at high pressure and high temperature in liquid and gaseous corrosive environment. Results from the tests will allow determining the fatigue life of several materials influenced by pressure and temperature under corrosive conditions.
On the terms mass and weight
(2008)
Im Rahmen eines gemeinschaftlichen Projektes der Stahl- und Automobilindustrie wurden für 17 Stahlfeinbleche des Automobilbaus in verschiedenen Anlieferungs- und Verformungszuständen unter -40°C, Raumtemperatur und +100°C mit 37 Versuchsreihen Anrisswöhlerlinien und zügige bzw. zyklische Spannung-Dehnung-Kurven bestimmt. Sämtliche Versuchspunkte, Hysteresen und ermittelte zyklische Kennwerte liegen in einer Datenbank vor. Eine Korrelationen zwischen den Kennwerten aus dem Zugversuch und den Kennwerten aus den zyklischen, dehnungsgeregelten Versuchen ist grundsätzlich möglich.
Insects with complete metamorphosis (holometaboly) are extremely successful, constituting over 60% of all described animal species. Complete metamorphosis confers significant advantages because it enables organisms to optimise life-history components through temporal partitioning, and thereby to exploitmultiple ecological niches. Yet holometaboly can also impose costs, and several lineages have evolved life cycle modifications to avoid complete metamorphosis.
In this review, we discuss different strategies that have evolved that result in the loss of complete metamorphosis (type I and type II paedomorphosis). In addition, the ecological pressures and developmental modifications that facilitate this avoidance are considered, as well as the importance of life cycle complexity in life-history evolution. Interestingly, only female holometabolous insects have entirely avoided complete metamorphosis, and it is always the ancestrally juvenile morphology that is retained. These findings point to a strong sex-biased trade-off between investment in reproduction and development. While the loss of complete metamorphosis in females has occurred independently on several occasions across holometabolous insects, only a small number of species possessing this ability have been described.
Thus, complete metamorphosis, which originated only once in insects, appears to have been almost fully retained. This indicates that significant modifications to the holometabolan metamorphic ground plan are highly constrained, and suggests that the transition to complete metamorphosis is evolutionarily irreversible.
The lab-on-valve (LOV) is a mesofluidic platform that has been recently exploited for
the automation and miniaturization of bioanalytical assays, resorting namely to
molecular recognition schemes based on immunosensing. Due to its high versatility
for reagent accommodation, it is possible to establish immunoassays under several
formats (eg. direct competitive ELISA, sandwich ELISA or even label-free immunoaffinity
chromatography). For instance, the LOV has been used as a manifold for
UV-vis micro-Bead Injection Spectroscopy (μ-BIS), a technique that involves the
quantification of the target analyte by direct measurement on the surface of a solid
phase capable of retaining the target analyte by molecular recognition.
The μ-BIS-LOV strategy affords several analytical advantages, namely short time-toresult
intervals (3 to 15 min), low sample volume (1-20 μL), automated solution handling
and washing steps, downscaling of reagents’ consumption, low-cost analysis
and little generation of waste. Additionally, the solid support is renewed before each
determination, minimizing surface fouling, cross-contamination issues and functional
group deactivation. No sample clean-up steps are required because interferences
are separated from the target analyte upon quantification mediated by a molecular
recognition element attached to the micro-bead column. The portability of the LOV
device makes it compatible with point-of-care testing.
To our knowledge, this technique has been mainly employed for the evaluation and
optimization of bioaffinity processes, but its potential for clinical and environmental
analysis remains underexploited. Hence, in this communication, different immunosensing
strategies using the LOV platform will be addressed, namely the determination
of autoimmune IgG in human serum, and the assessment of drug (carbamazepine)
levels in wastewater samples.
The research project focuses on tackling the detection, measurement, and elimination of per- and polyfluoroalkyl substances (PFAS) from polluted groundwater, with a particular emphasis on addressing short (C4-C7) and ultrashort (C1-C3) chain PFAS. Given the widespread use of PFAS in various products, they are commonly found in groundwater near industrial and military sites in Germany and Israel. Moreover, recent regulations limiting the use of long chain PFAS have led industries to shift towards shorter chain alternatives. Hence, our efforts are geared towards refining detection, quantification, and removal methods for short and ultrashort chain PFAS. In terms of detection, ww are developing passive sampling devices capable of collecting and tracking the temporal distribution of PFAS species in groundwater. This will enable us to analyze contaminations in German and Israeli groundwater using cutting-edge analytical techniques. Additionally, contaminated groundwater will undergo a two-stage treatment process aimed at concentrating the relatively low PFAS concentrations using innovative membrane technologies such as closed-circuit reverse osmosis and mixed matrix composite nanofiltration membrane adsorbers. Subsequently, the streams containing higher PFAS concentrations will be treated through coagulation, with the remaining PFAS being adsorbed onto carbonaceous nanomaterials. The outcome of this research will include the creation of advanced tools for detecting, measuring, and eliminating PFAS from polluted groundwater, while also enhancing our understanding of the scope of these contaminations.
Estimating the frequency and magnitude of natural hazards largely hinges on stationary models, which do not account for changes in the climatological, hydrological, and geophysical baseline conditions. Using five diverse case studies encompassing various natural hazard types, we present advanced statistical and machine learning methods to analyze and model transient states from long‐term inventory data. A novel storminess metric reveals increasing European winter windstorm severity from 1950 to 2010. Non‐stationary extreme value models quantify trends, seasonal shifts, and regional differences in extreme precipitation for Germany between 1941 and 2021. Utilizing quantile sampling and empirical mode decomposition on 148 years of daily weather and discharge data in the European Alps, we assess the impacts of changing snow cover, precipitation, and anthropogenic river network modifications on river runoff. Moreover, a probabilistic framework estimates return periods of glacier lake outburst floods in the Himalayas, demonstrating large differences in 100‐year flood levels. Utilizing a Bayesian change point algorithm, we track the onset of increased seismicity in the southern central United States and find correlation with wastewater injections into deep wells. In conclusion, data science reveals transient states for very different natural hazard types, characterized by diverse forms of change, ranging from gradual trends to sudden change points and from altered seasonality to overall intensity variations. In synergy with the physical understanding of Earth science, we gain important new insights into the dynamics of the studied hazards and their possible mechanisms.
Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils
(2021)
Dust deposition is an important source of phosphorus (P) to many ecosystems. However, there is little evidence of dust-derived P-containing minerals in soils. Here we studied P forms along a well-described climatic Gradient on Hawaii, which is also a dust deposition gradient. Soil mineralogy and soil P forms from six sites along the climatic gradient were analyzed with bulk (X-ray diffraction and P K-edge X-ray absorption near edge structure) and microscale (X-ray fluorescence, P K-edge X-ray absorption near edge structure, and Raman) analysis methods. In the wettest soils, apatite grains ranging from 5 to 30 μm in size were co-located at the micro-scale with quartz, a known continental dust indicator suggesting recent atmospheric deposition. In addition to co-location with quartz, further evidence of dust-derived P included backward trajectory modeling indicating that dust particles could be brought to Hawaii from the major global dust-loading areas in central Asia and northern Africa. Although it is not certain whether the individual observed apatite grains were derived from long-distance transport of dust, or from local dust sources such as volcanic ash or windblown fertilizer, these observations offer direct evidence that P-containing minerals have reached surface layers of highly-weathered grassland soils through atmospheric deposition.
Femtosecond (fs) laser pulse ablation (pulse duration of 150 fs, wavelength of 775 nm, repetition rate of 1 kHz) of single-crystalline TeO2 surfaces was performed in air using the direct focusing technique. The lateral and vertical dimensions of laser ablated craters as well as the laser damage thresholds were evaluated for different pulse numbers applied to the same spot. The joint observation using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters and also showed that the ablation threshold depends significantly on the number of laser pulses applied to the same spot due to incubation effects. The incubation effects change the absorption processes involved in fs-laser ablation of the transparent material from multiphoton absorption to a single-photon absorption. These results are discussed on the basis of recent models of the interaction of fs-laser pulses with dielectrics.
The conventional hybridoma screening and subcloning process is generally considered to be one of the most critical steps in hapten-specific antibody production. It is time-consuming, monoclonality is not guaranteed, and the number of clones that can be screened is limited. Our approach employs a novel hapten-specific labeling technique of hybridoma cells. This allows for fluorescence-activated cell sorting (FACS) and single-cell deposition and thereby eliminates the above-mentioned problems. A two-step staining approach is used to detect antigen specificity and antibody expression: in order to detect antigen specificity, hybridoma cells are incubated with a hapten−horseradish peroxidase conjugate (hapten−HRP), which is subsequently incubated with a fluorophore-labeled polyclonal anti-peroxidase antibody (anti-HRP−Alexa Fluor 488). To characterize the expression of membrane-bound immunoglobulin G (IgG), a fluorophore-labeled anti-mouse IgG antibody (anti-IgG−Alexa Fluor 647) is used. Hundreds of labeled hybridoma cells producing monoclonal antibodies (mAbs) specific for a hapten were rapidly isolated and deposited from a fusion mixture as single-cell clones via FACS. Enzyme-linked immunosorbent assay (ELISA) measurements of the supernatants of the sorted hybridoma clones revealed that all hapten-specific hybridoma clones secrete antibodies against the target. There are significant improvements using this high-throughput technique for the generation of mAbs including increased yield of antibody-producing hybridoma clones, ensured monoclonality of sorted cells, and reduced development times.
Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes.