Graph-theoretical prediction of biological modules in quaternary structures of large protein complexes.

MOTIVATION: The functional complexity of biochemical processes is strongly related to the interplay of proteins and their assembly into protein complexes. In recent years, the discovery and characterization of protein complexes have substantially progressed through advances in cryo-electron microscopy, proteomics, and computational structure prediction. This development results in a strong need for computational approaches to analyse the data of large protein complexes for structural and functional characterization. Here, we aim to provide a suitable approach, which processes the growing number of large protein complexes, to obtain biologically meaningful information on the hierarchical organization of the structures of protein complexes. RESULTS: We modelled the quaternary structure of protein complexes as undirected, labelled graphs called complex graphs. In complex graphs, the vertices represent protein chains and the edges spatial chain-chain contacts. We hypothesized that clusters based on the complex graph correspond to functional biological modules. To compute the clusters, we applied the Leiden clustering algorithm. To evaluate our approach, we chose the human respiratory complex I, which has been extensively investigated and exhibits a known biological module structure experimentally validated. Additionally, we characterized a eukaryotic group II chaperonin TRiC/CCT and the head of the bacteriophage Φ29. The analysis of the protein complexes correlated with experimental findings and indicated known functional, biological modules. Using our approach enables not only to predict functional biological modules in large protein complexes with characteristic features but also to investigate the flexibility of specific regions and coformational changes. The predicted modules can aid in the planning and analysis of experiments. AVAILABILITY AND IMPLEMENTATION: Jupyter notebooks to reproduce the examples are available on our public GitHub repository: https://github.com/MolBIFFM/PTGLtools/tree/main/PTGLmodulePrediction.

A Novel Monoclonal Antibody Degrades the Thyrotropin Receptor Autoantibodies in Graves' Disease.

OBJECTIVE: Autoantibodies against the thyrotropin receptor (TSH-R-Ab) are key mediators for the pathogenesis of Graves' disease (GD). TSH-R-Ab degradation was evaluated using several immunoassays within an exploratory, controlled trial in patients with GD receiving a monoclonal antibody (mAb) targeting the neonatal crystallizable fragment receptor (FcRn). METHODS: Serial measurements of TSH-R-Ab serum levels were performed using 3 different binding and cell-based assays in patients with GD either on medication or on placebo. RESULTS: In contrast to the placebo group, in which no changes were observed, a 12-week mAb therapy led to an early and significant decrease (>60%) in the serum TSH-R-Ab levels in patients with thyroidal and extrathyroidal GD, as unanimously shown in all 3 assays. These marked changes were noted already at week 7 post baseline (P <.0001 for the binding immunoassay and for the luciferase (readout) bioassay). The 3 TSH-R-Ab binding and bioassays were highly correlated in the samples of both study groups (binding immunoassay vs luciferase bioassay, r =.91, P <.001, binding vs cyclic adenosine monophosphate (cAMP) bioassay, r = 0.86, P <.001, and luciferase vs cAMP bioassay, r = 0.71, P =.006). The serological results correlated with the course of the extrathyroidal clinical parameters of GD, that is, clinical activity score and proptosis. CONCLUSION: Targeting the FcRn markedly reduces the disease-specific TSH-R-Ab in patients with GD. The novel and rapid TSH-R-Ab bioassay improves diagnosis and management of patients with GD.

PTGL: extension to graph-based topologies of cryo-EM data for large protein structures.

SUMMARY: We provide a software to describe the topology of large protein complexes based mainly on cryo-EM data and stored as macromolecular Crystallographic Information Files (mmCIFs) in the PDB. The software extends the Protein Topology Graph Library and implements an efficient file parser to analyze mmCIFs. The extended Protein Topology Graph Library includes a graph-based representation of the topology of protein complexes on the supersecondary and quaternary structure level. The library holds topology graphs of 151 837 PDB files; 921 of them are large structures. The abstraction of protein structure complexes to undirected labeled graphs enables classification and comparison of large protein complexes on quaternary structure level. AVAILABILITY AND IMPLEMENTATION: Online access at http://ptgl.uni-frankfurt.de. Source code in Java under GNU public license 2.0 at https://github.com/MolBIFFM/vplg. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

A novel point-of-care device accurately measures thyrotropin in whole blood, capillary blood and serum.

OBJECTIVES: Point-of-care (POC) measurement of thyrotropin (TSH) may facilitate prompt diagnosis of thyroid dysfunction. We evaluated the analytical performance of a new POC TSH assay (Wondfo). METHODS: TSH measurements were made from 730 consecutive, unselected subjects in an outpatient setting, using Wondfo in whole blood, capillary blood and serum or automated reference equipment (serum only). RESULTS: TSH measurements were user-independent. Total intra-and inter-assay variation (CV%) was 12.1 and 16.2%, respectively. Total CV% was 10.6-22.6% and 14.5-21.6% in serum and whole blood, respectively. Linearity was very good. Recovery rate was 97-127%. Prolongation of incubation time increased TSH results of 12% (13%) and 33% (35%) after 2 and 5 additional minutes in serum (blood), respectively. When measured simultaneously in two Wondfo devices, the slope of the regression line was 1.03 (serum) and 1.02 (blood), with Spearman's correlation of 0.99 for both. TSH measurements between Wondfo and reference correlated strongly (r=0.93-0.96), though TSH measurements were lower with Wondfo (slopes of plots of measurements made using the two devices were 0.94 [serum vs. serum]; 0.83 [whole blood vs. serum] and 0.64 [capillary blood vs. serum]). Depending on sample material, TSH in capillary blood was lower vs. whole blood (slope: 0.82) and for whole blood vs. serum (Wondfo and reference method; slope: 0.69 and 0.83). Total haemolysis, but not elevated bilirubin or lipemia, disrupted TSH measurement. CONCLUSIONS: The Wondfo system was straightforward to use without need for specialist technicians and demonstrated analytic performance suitable for clinical use for the diagnosis of thyroid dysfunction.

The Pectobacterium pangenome, with a focus on Pectobacterium brasiliense, shows a robust core and extensive exchange of genes from a shared gene pool.

BACKGROUND: Bacterial plant pathogens of the Pectobacterium genus are responsible for a wide spectrum of diseases in plants, including important crops such as potato, tomato, lettuce, and banana. Investigation of the genetic diversity underlying virulence and host specificity can be performed at genome level by using a comprehensive comparative approach called pangenomics. A pangenomic approach, using newly developed functionalities in PanTools, was applied to analyze the complex phylogeny of the Pectobacterium genus. We specifically used the pangenome to investigate genetic differences between virulent and avirulent strains of P. brasiliense, a potato blackleg causing species dominantly present in Western Europe. RESULTS: Here we generated a multilevel pangenome for Pectobacterium, comprising 197 strains across 19 species, including type strains, with a focus on P. brasiliense. The extensive phylogenetic analysis of the Pectobacterium genus showed robust distinct clades, with most detail provided by 452,388 parsimony-informative single-nucleotide polymorphisms identified in single-copy orthologs. The average Pectobacterium genome consists of 47% core genes, 1% unique genes, and 52% accessory genes. Using the pangenome, we zoomed in on differences between virulent and avirulent P. brasiliense strains and identified 86 genes associated to virulent strains. We found that the organization of genes is highly structured and linked with gene conservation, function, and transcriptional orientation. CONCLUSION: The pangenome analysis demonstrates that evolution in Pectobacteria is a highly dynamic process, including gene acquisitions partly in clusters, genome rearrangements, and loss of genes. Pectobacterium species are typically not characterized by a set of species-specific genes, but instead present themselves using new gene combinations from the shared gene pool. A multilevel pangenomic approach, fusing DNA, protein, biological function, taxonomic group, and phenotypes, facilitates studies in a flexible taxonomic context.

Comparative Studies on the Disease Prevalence and Population Dynamics of Ginger Blotch and Brown Blotch Pathogens of Button Mushrooms.

Bacterial blotch is one of the most economically important diseases of button 'mushroom. Knowledge of mechanisms of disease expression, inoculum thresholds, and disease management is limited to the most well-known pathogen, Pseudomonas tolaasii. Recent outbreaks in Europe have been attributed to 'P. gingeri' and P. salomonii for ginger and brown blotch, respectively. Information about their identity, infection dynamics, and pathogenicity is largely lacking. The disease pressure in an experimental mushroom cultivation facility was evaluated for 'P. gingeri' and P. salomonii over varying inoculation densities, casing soil types, environmental humidity, and cultivation cycles. The pathogen population structures in the casing soils were simultaneously tracked across the cropping cycle using highly specific and sensitive TaqMan-quantitative PCR assays. 'P. gingeri' caused disease outbreaks at lower inoculum thresholds (104 CFU/g) in the soil than P. salomonii (105 CFU/g). Ginger blotch generically declined in later harvest cycles, although brown blotch did not. Casing soils were differentially suppressive to blotch diseases, based on their composition and supplementation. Endemic pathogen populations increased across the cultivation cycle although the inoculated pathogen populations were consistent between the first and second flush. In conclusion, 'P. gingeri' and P. salomonii have unique infection and population dynamics that vary over soil types. Their endemic populations are also differently abundant in peat-based casing soils. This knowledge is essential for interpreting diagnostic results from screening mushroom farms and designing localized disease control strategies.

Genome Resource of Two Potato Strains of Ralstonia solanacearum Biovar 2 (Phylotype IIB Sequevar 1) and Biovar 2T (Phylotype IIB Sequevar 25) Isolated from Lowlands in Iran.

Ralstonia solanacearum, the causal agent of bacterial wilt and brown rot disease, is one of the major pathogens of solanaceous crops, including potato, around the globe. Biovar 2T (phylotype II/sequevar 25) of R. solanacearum is adapted to tropical lowlands and is only reported in South America and Iran. Thus far, no genome resource of the biovar 2T of the pathogen has been available. Here, we present the near-complete genome sequences of the biovar 2T strain CFBP 8697 as well as strain CFBP 8695 belonging to biovar 2 race 3, both isolated from potato in Iran. The genomic data of biovar 2T will extend our understanding of the virulence features of R. solanacearum and pave the way for research on biovar 2T functional and interaction genetics.

Molecular characterization of Pseudomonas from Agaricus bisporus caps reveal novel blotch pathogens in Western Europe.

BACKGROUND: Bacterial blotch is a group of economically important diseases affecting the cultivation of common button mushroom, Agaricus bisporus. Despite being studied for more than a century, the identity and nomenclature of blotch-causing Pseudomonas species is still unclear. This study aims to molecularly characterize the phylogenetic and phenotypic diversity of blotch pathogens in Western Europe. METHODS: In this study, blotched mushrooms were sampled from farms across the Netherlands, United Kingdom and Belgium. Bacteria were isolated from symptomatic cap tissue and tested in pathogenicity assays on fresh caps and in pots. Whole genome sequences of pathogenic and non-pathogenic isolates were used to establish phylogeny via multi-locus sequence alignment (MLSA), average nucleotide identity (ANI) and in-silico DNA:DNA hybridization (DDH) analyses. RESULTS: The known pathogens "Pseudomonas gingeri", P. tolaasii, "P. reactans" and P. costantinii were recovered from blotched mushroom caps. Seven novel pathogens were also identified, namely, P. yamanorum, P. edaphica, P. salomonii and strains that clustered with Pseudomonas sp. NC02 in one genomic species, and three non-pseudomonads, i.e. Serratia liquefaciens, S. proteamaculans and a Pantoea sp. Insights on the pathogenicity and symptom severity of these blotch pathogens were also generated. CONCLUSION: A detailed overview of genetic and regional diversity and the virulence of blotch pathogens in Western Europe, was obtained via the phylogenetic and phenotypic analyses. This information has implications in the study of symptomatic disease expression, development of diagnostic tools and design of localized strategies for disease management.

Atmospheric Pressure MALDI Mass Spectrometry Imaging Using In-Line Plasma Induced Postionization.

Atmospheric pressure ionization methods confer a number of advantages over more traditional vacuum based techniques, in particular ease of hyphenation to a range of mass spectrometers. For atmospheric pressure matrix assisted desorption/ionization (AP-MALDI), several ion sources, operating in a range of geometries have been reported. Most of these platforms have, to date, generally demonstrated relatively low ion yields and/or poor ion transmission compared to vacuum sources. To improve the detection of certain ions, we have developed a second-generation transmission mode (TM) AP-MALDI imaging platform with in-line plasma postionization using the commercially available SICRIT device, replacing the previously used low temperature plasma probe from our developmental AP-TM-MALDI stage. Both plasma devices produce a significant ionization enhancement for a range of compounds, but the overall higher enhancement obtained by the SICRIT device in addition to the ease of installation and the minimal need for optimization presents this commercially available tool as an attractive method for simple postionization in AP-MALDI MSI.

Pectobacterium parvum sp. nov., having a Salmonella SPI-1-like Type III secretion system and low virulence.

Pectobacterium strains isolated from potato stems in Finland, Poland and the Netherlands were subjected to polyphasic analyses to characterize their genomic and phenotypic features. Phylogenetic analysis based on 382 core proteins showed that the isolates clustered closest to Pectobacterium polaris but could be divided into two clades. Average nucleotide identity (ANI) analysis revealed that the isolates in one of the clades included the P. polaris type strain, whereas the second clade was at the border of the species P. polaris with a 96 % ANI value. In silico genome-to-genome comparisons between the isolates revealed values below 70%, patristic distances based on 1294 core proteins were at the level observed between closely related Pectobacterium species, and the two groups of bacteria differed in genome size, G+C content and results of amplified fragment length polymorphism and Biolog analyses. Comparisons between the genomes revealed that the isolates of the atypical group contained SPI-1-type Type III secretion island and genes coding for proteins known for toxic effects on nematodes or insects, and lacked many genes coding for previously characterized virulence determinants affecting rotting of plant tissue by soft rot bacteria. Furthermore, the atypical isolates could be differentiated from P. polaris by their low virulence, production of antibacterial metabolites and a citrate-negative phenotype. Based on the results of a polyphasic approach including genome-to-genome comparisons, biochemical and virulence assays, presented in this report, we propose delineation of the atypical isolates as a novel species Pectobacterium parvum, for which the isolate s0421T (CFBP 8630T=LMG 30828T) is suggested as a type strain.

Potato-Infecting Ralstonia solanacearum Strains in Iran Expand Knowledge on the Global Diversity of Brown Rot Ecotype of the Pathogen.

Bacterial wilt and brown rot disease caused by Ralstonia solanacearum species complex (RSSC) is one of the major constraints of potato (Solanum tuberosum) production around the globe. During 2017 to 2018, an extensive field survey was conducted in six potato-growing provinces of Iran to monitor the status of bacterial wilt disease. Pathogenicity and host range assays using 59 bacterial strains isolated in Iran showed that they were pathogenic on eggplant, red nightshade, pepper, potato and tomato, while nonpathogenic on common bean, cowpea, cucumber, sunflower, zinnia and zucchini. PCR-based diagnosis revealed that the strains belong to the phylotype IIB/sequevar 1 (IIB/I) lineage of the RSSC. Furthermore, a five-gene multilocus sequence analysis and typing (egl, fliC, gyrB, mutS, and rplB) confirmed the phylogenetically near-homogeneous nature of the strains within IIB/I lineage. Four sequence types were identified among 58 IIB/1 strains isolated in Iran. Phylogenetically near-homogeneous nature of the strains in Iran raise questions about the mode of inoculum entry of the bacterial wilt pathogen into the country (one-time introduction versus multiple introductions), while the geographic origin of the Iranian R. solanacearum strains remains undetermined. Furthermore, sequence typing showed that there were shared alleles (haplotypes) and sequence types among the strains isolated in geographically distant areas in Iran, suggesting intranational transmission of the pathogen in the country.

Development and Evaluation of a Triplex TaqMan Assay and Next-Generation Sequence Analysis for Improved Detection of Xylella in Plant Material.

Xylella fastidiosa is a heterogenous gram-negative bacterial plant pathogen with a wide host range covering over 300 plant species. Since 2013, in Europe, the presence of the pathogen is increasing in a part of the Mediterranean area, but it causes in particular severe disease problems in olive orchards in the Southern part of Italy. Various subspecies of the pathogen were also diagnosed in natural outbreaks and intercepted ornamental plants in Europe, among them Olea europaea, Coffea arabica, and Nerium oleander. The host range of the pathogen can vary, depending on the subspecies and even the strain. The availability of fast and reliable diagnostic tools is indispensable in management strategies to control diseases caused by X. fastidiosa. To improve the reliability of the TaqMan assay, currently widely used in surveys, a triplex TaqMan assay was developed in which two specific and sensitive TaqMan assays, previously designed for X. fastidiosa, were combined with an internal control. The triplex assay exhibited the same diagnostic sensitivity as the simplex assays. In addition, the usefulness of a metagenomic approach using next-generation sequencing (NGS) was demonstrated, in which total DNA extracted from plant material was sequenced. DNA extracts from plant material free of X. fastidiosa, from artificially inoculated hosts plants or from naturally infected plants sampled in France, Spain, and Italy, or intercepted in Austria and the Netherlands, were analyzed for the presence of X. fastidiosa using the metagenomic approach. In all samples, even in samples with a low infection level, but not in the pathogen-free samples, DNA reads were detected specific for X. fastidiosa. In most cases, the pathogen could be identified to the subspecies level, and for one sample even the whole genome could be assembled and the sequence type could be determined. All results of NGS-analyzed samples were confirmed with the triplex TaqMan polymerase chain reaction and loop-mediated isothermal amplification.

Mechanistic Understanding Leads to Increased Ionization Efficiency and Selectivity in Dielectric Barrier Discharge Ionization Mass Spectrometry: A Case Study with Perfluorinated Compounds.

Perfluorinated compounds have unique properties and many practical applications, but are difficult to ionize efficiently with soft ionization methods. An active capillary plasma ionization source based on dielectric barrier discharge ionization (DBDI) coupled with mass spectrometry was used to study the ionization pathway of perfluorinated compounds (PFCs), with the aim of both increasing the ionization efficiency and influencing the selectivity for generating product ions in negative ion mode. Cyclic and linear perfluorinated alkanes were found to mainly form [M - F]- and [M - F + O]- ions, respectively; the [M]-• ion was only obtained at low discharge voltage. Additionally, fluorine attachment [M + F]- was observed mostly for perfluorinated alkenes. An isotope labeling experiment with 18O2 showed that the primary source of oxygen in the substitution reaction is molecular oxygen, reacting with the analyte in the form of O-• ions. The abundance of [M - F + O]- ions can thus be enhanced by increasing the plasma voltage to produce a higher O-• ion density. The loss of the fluorine (without substitution by oxygen) was mainly observed at high frequency, a fact which can be exploited for tuning the ionization toward specific product ions. Overall, the mechanistic understanding of the ionization of PFCs allowed to increase the selectivity of the product ions, resulting in increased ionization efficiency.

Genetic Characterization of Clavibacter michiganensis subsp. michiganensis Population in Turkey.

The pathogenic gram-positive bacterium Clavibacter michiganensis subsp. michiganensis (Smith) Davis et al. is the most harmful bacterium to tomatoes in many countries with a cooler climate. Multilocus sequence analysis was performed on five housekeeping genes (bipA, gyrB, kdpA, ligA, and sdhA) and three virulence-related genes (ppaA, chpC, and tomA) to determine evolutionary relationships and population structure of 108 C. michiganensis subsp. michiganensis strains collected from Turkey between 1996 and 2012. Based on these analyses, we concluded that C. michiganensis subsp. michiganensis in Turkey is highly uniform. However, at least four novel C. michiganensis subsp. michiganensis strains were recently introduced, possibly at the beginning of the 1990s. The singletons might point to additional sources or to strains that have evolved locally in Turkey.

Atmospheric pressure soft ionization for gas chromatography with dielectric barrier discharge ionization-mass spectrometry (GC-DBDI-MS).

In this study, a gas chromatography (GC) system was interfaced to a high-resolution Orbitrap mass spectrometer by means of an active capillary plasma ionization source, based on dielectric barrier discharge ionization (DBDI). This allowed highly efficient soft ionization of gas-phase, chromatographically resolved compounds at ambient pressure. Several pesticides and illicit drugs were analyzed, and the limits of detections (LODs) were as low as 30 pg mL-1 for the GC-DBDI-MS coupling (corresponding to 60 fg on-column sensitivity) and 30 fg mL-1 for SPME-GC-DBDI-MS.

Effectiveness and tolerability of parenteral testosterone undecanoate: a post-marketing surveillance study.

This observational post-marketing study of parenteral testosterone undecanoate (TU) in a non-selected population aimed to: examine the effectiveness of TU as treatment of hypogonadism; record adverse drug reactions (ADR) quantitatively particularly regarding polycythemia, prostate safety and cardiovascular-related metabolic risk factors; and verify whether recommended injection intervals apply to routine clinical practice. Eight hundred and seventy subjects from 259 outpatient units scheduled to visit the clinic six times were included. Effectiveness and tolerability of TU administration were assessed on a 4-point scale. Body weight, waist girth, blood pressure, hemoglobin levels, hematocrit, prostate-specific antigen (PSA), and digital rectal prostate examination were assessed. Over 90% of subjects completed the observational duration of 52.8 ± 9.7 weeks (mean ± SD) and 56% judged effectiveness as very good, 30.8% as good. 63.1% judged tolerability as very good, and 24.4% as good. No adverse effects on indicators of cardiovascular risk were observed. Polycythemia occurred in one subject and a supranormal hematocrit in one subject. Four subjects developed supranormal PSA levels. Prostate carcinoma was found in one subject, one subject had recurrence of a previously surgically treated prostate carcinoma, and the other two showed no indication of malignancy. Parenteral TU is safe, effective, and well-tolerated in clinical practice proving a good therapeutic option for hypogonadism.

Direct Coupling of Solid-Phase Microextraction with Mass Spectrometry: Sub-pg/g Sensitivity Achieved Using a Dielectric Barrier Discharge Ionization Source.

We report a new strategy for the direct coupling of Solid-Phase Microextraction (SPME) with mass spectrometry, based on thermal desorption of analytes extracted on the fibers, followed by ionization by a dielectric barrier discharge ionization (DBDI) source. Limits of detection as low as 0.3 pg/mL and a linear dynamic range of ≥3 orders of magnitude were achieved, with a very simple and reproducible approach. Different from direct analysis in real time (DART), desorption electrospray ionization (DESI), or low-temperature plasma (LTP), the desorption of the analytes from the SPME devices in our setup is completely separated from the ionization event. This enhances the reproducibility of the method and minimizes ion suppression phenomena. The analytes were quantitatively transferred from the SPME to the DBDI source, and the use of an active capillary ionization embodiment of the DBDI source greatly enhanced the ion transmission to the MS. This, together with the extraordinary sensitivity of DBDI, allowed subpg/mL sensitivities to be reached and to skip conventional and time-consuming chromatographic separation.

Pesticide analysis at ppt concentration levels: coupling nano-liquid chromatography with dielectric barrier discharge ionization-mass spectrometry.

We report the coupling of nano-liquid chromatography (nano-LC) with an ambient dielectric barrier discharge ionization (DBDI)-based source. Detection and quantification were carried out by high-resolution mass spectrometry (MS), using an LTQ-Orbitrap in full scan mode. Despite the fact that nano-LC systems are rarely used in food analysis, this coupling was demonstrated to deliver extremely high sensitivity in pesticide analysis, with limits of detection (LODs) as low as 10 pg/mL. In all cases, the limits of quantification (LOQs) were compliant with the current EU regulation. An excellent signal linearity over up to four orders of magnitude was also observed. Therefore, this method can easily compete with conventional GC-(EI)-MS or LC-ESI-MS/MS methods and in some cases outperform them. The method was successfully tested for food sample analysis, with apples and baby food, extracted using the QuEChERS approach. Our results demonstrate an outstanding sensitivity (at femtogram level) and reproducibility of the nano-LC-DBDI coupling, capable of improving routine pesticide analysis. To the best of our knowledge, this is the most sensitive and reproducible plasma-MS-based method for pesticide analysis reported to date.

Direct quantification of chemical warfare agents and related compounds at low ppt levels: comparing active capillary dielectric barrier discharge plasma ionization and secondary electrospray ionization mass spectrometry.

A novel active capillary dielectric barrier discharge plasma ionization (DBDI) technique for mass spectrometry is applied to the direct detection of 13 chemical warfare related compounds, including sarin, and compared to secondary electrospray ionization (SESI) in terms of selectivity and sensitivity. The investigated compounds include an intact chemical warfare agent and structurally related molecules, hydrolysis products and/or precursors of highly toxic nerve agents (G-series, V-series, and "new" nerve agents), and blistering and incapacitating warfare agents. Well-defined analyte gas phase concentrations were generated by a pressure-assisted nanospray with consecutive thermal evaporation and dilution. Identification was achieved by selected reaction monitoring (SRM). The most abundant fragment ion intensity of each compound was used for quantification. For DBDI and SESI, absolute gas phase detection limits in the low ppt range (in MS/MS mode) were achieved for all compounds investigated. Although the sensitivity of both methods was comparable, the active capillary DBDI sensitivity was found to be dependent on the applied AC voltage, thus enabling direct tuning of the sensitivity and the in-source fragmentation, which may become a key feature in terms of field applicability. Our findings underline the applicability of DBDI and SESI for the direct, sensitive detection and quantification of several CWA types and their degradation products. Furthermore, they suggest the use of DBDI in combination with hand-held instruments for CWAs on-site monitoring.