Enzymatic reactions in confined environments

Within each biological cell, surface- and volume-confined enzymes control a highly complex network of chemical reactions. These reactions are efficient, timely, and spatially defined. Efforts to transfer such appealing features to in vitro systems have led to several successful examples of chemical reactions catalysed by isolated and immobilized enzymes. In most cases, these enzymes are either bound or adsorbed to an insoluble support, physically trapped in a macromolecular network, or encapsulated within compartments. Advanced applications of enzymatic cascade reactions with immobilized enzymes include enzymatic fuel cells and enzymatic nanoreactors, both for in vitro and possible in vivo applications. In this Review, we discuss some of the general principles of enzymatic reactions confined on surfaces, at interfaces, and inside small volumes. We also highlight the similarities and differences between the in vivo and in vitro cases and attempt to critically evaluate some of the necessary future steps to improve our fundamental understanding of these systems

Qualitative and Quantitative Detection of Botulinum Neurotoxins from Complex Matrices: Results of the First International Proficiency Test

In the framework of the EU project EQuATox a first international proficiency test (PT) on the detection and quantification of BoNT was conducted. Sample materials included BoNT serotypes A, B and E spiked into buffer, milk, meat extract and serum. A variety of methods was applied by the participants combining different principles of detection, identification and quantification. Based on qualitative assays, 95% of all results reported were correct. Successful strategies for BoNT detection were based on a combination of complementary immunological, MS-based and functional methods or on suitable functional in vivo / in vitro approaches (mouse bioassay, hemidiaphrama assay, Endopep-MS assay). Quantification of BoNT/A, BoNT/B and BoNT/E was performed by 48% of participating laboratories. It turned out that precise quantification of BoNT was difficult resulting in a substantial scatter of quantitative data. This was especially true for results obtained by the mouse bioassay which is currently seen as “gold standard” for BoNT detection. The results clearly demonstrate the urgent need of certified BoNT reference materials and the development of methods replacing animal testing. In this context, the BoNT PT provided the valuable information that both the Endopep-MS assay and the hemidiaphrama assay delivered quantitative results superior to the mouse bioassay.JRC.D.2-Standards for Innovation and sustainable Developmen

Quantitation of Guggenheimella bovis and treponemes in bovine tissues related to digital dermatitis

Digital dermatitis is an inflammation of uncertain aetiology in the skin of the foot of cattle. In 2005, a novel microorganism, Guggenheimella bovis, was isolated from the advancing front of digital dermatitis lesions, suggesting a possible role in pathogenesis. In the present study, tissue samples of 20 affected cows were examined by quantitative PCR for G. bovis, treponemes and the total eubacterial load. High numbers of eubacteria and treponemes were found in most lesions, whereas only a few lesions contained Guggenheimella, and only at low concentrations. The results argue against the relevance of G. bovis in the aetiology of digital dermatitis in cattle, but are consistent with a role for treponeme

Results of a Saxitoxin Proficiency Test Including Characterization of Reference Material and Stability Studies

A saxitoxin (STX) proficiency test (PT) was organized as part of the Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk (EQuATox) project. The aim of this PT was to provide an evaluation of existing methods and the European laboratories' capabilities for the analysis of STX and some of its analogues in real samples. Homogenized mussel material and algal cell materials containing paralytic shellfish poisoning (PSP) toxins were produced as reference sample matrices. The reference material was characterized using various analytical methods. Acidified algal extract samples at two concentration levels were prepared from a bulk culture of PSP toxins producing dinoflagellate Alexandrium ostenfeldii. The homogeneity and stability of the prepared PT samples were studied and found to be fit-for-purpose. Thereafter, eight STX PT samples were sent to ten participating laboratories from eight countries. The PT offered the participating laboratories the possibility to assess their performance regarding the qualitative and quantitative detection of PSP toxins. Various techniques such as official Association of Official Analytical Chemists (AOAC) methods, immunoassays, and liquid chromatography-mass spectrometry were used for sample analyses.Peer reviewe

Umfang und Bedeutung des durch die Post abgewickelten Zahlungsverkehrs in der Schweiz

Das Ziel der Studie ist die Darstellung des volkswirtschaftlichen Stellenwertes des Post-Zahlungsverkehrs. Die Arbeit soll als Grundlage für die politischen Entscheide über Inhalt, Ausgestaltung und Regulierung des Grundversorgungsauftrages dienen

Automated High-Throughput Analysis of Tramadol and O-Desmethyltramadol in Dried Blood Spots.

The World Anti-Doping Agency (WADA) and the International Testing Agency (ITA) recently announced the development and implementation of dried blood spot (DBS) testing for routine analysis in time for the 2022 Winter Olympic and Paralympic Games in Beijing. Following the introduction of a ban on the use of Tramadol in competition in March 2019, the Union Cycliste International (UCI) started a pilot study for the manual analysis of Tramadol in DBS for anti-doping purposes. In this context, we present a fully automated LC-MS/MS-based method with automated sample preparation using a CAMAG DBS-MS 500 for the analysis of tramadol and its metabolite O-desmethyltramadol in DBS. The presented approach reduces manual handling in the laboratory to an absolute minimum, only requiring the preparation of calibration and quality control DBS cards. The method was developed, optimized, and validated before performing cross-validation with a liquid blood-based analysis method using authentic samples from forensic cases. During the validation process, the method showed an extraction efficiency of 62%, linearity r2 >0.99, accuracy and precision (within ±15% and ±20% at the LLOQ) for the determination of tramadol and O-desmethyltramadol. Method comparison in liquid blood with 26 samples showed good agreement (90±19% for tramadol and 94±14% for O-desmethyltramadol). In conclusion, automated analysis of tramadol and O-desmethyltramadol in DBS provides a fast and accurate solution for anti-doping screening. It is suited for high-throughput analysis, having a run time of about 4 min per sample. Furthermore, with the automated approach, manual sample extraction becomes obsolete

Qualitative and Quantitative Detection of Botulinum Neurotoxins from Complex Matrices: Results of the First International Proficiency Test

In the framework of the EU project EQuATox, a first international proficiency test (PT) on the detection and quantification of botulinum neurotoxins (BoNT) was conducted. Sample materials included BoNT serotypes A, B and E spiked into buffer, milk, meat extract and serum. Different methods were applied by the participants combining different principles of detection, identification and quantification. Based on qualitative assays, 95% of all results reported were correct. Successful strategies for BoNT detection were based on a combination of complementary immunological, MS-based and functional methods or on suitable functional in vivo/in vitro approaches (mouse bioassay, hemidiaphragm assay and Endopep-MS assay). Quantification of BoNT/A, BoNT/B and BoNT/E was performed by 48% of participating laboratories. It turned out that precise quantification of BoNT was difficult, resulting in a substantial scatter of quantitative data. This was especially true for results obtained by the mouse bioassay which is currently considered as “gold standard” for BoNT detection. The results clearly demonstrate the urgent need for certified BoNT reference materials and the development of methods replacing animal testing. In this context, the BoNT PT provided the valuable information that both the Endopep-MS assay and the hemidiaphragm assay delivered quantitative results superior to the mouse bioassay

Quantitation of Guggenheimella bovis and treponemes in bovine tissues related to digital dermatitis

Digital dermatitis is an inflammation of uncertain aetiology in the skin of the foot of cattle. In 2005, a novel microorganism, Guggenheimella bovis, was isolated from the advancing front of digital dermatitis lesions, suggesting a possible role in pathogenesis. In the present study, tissue samples of 20 affected cows were examined by quantitative PCR for G. bovis, treponemes and the total eubacterial load. High numbers of eubacteria and treponemes were found in most lesions, whereas only a few lesions contained Guggenheimella, and only at low concentrations. The results argue against the relevance of G. bovis in the aetiology of digital dermatitis in cattle, but are consistent with a role for treponemes

Efficient cell-specific uptake of binding proteins into the cytoplasm through engineered modular transport systems

Through advances in protein scaffold engineering and selection technologies, highly specific binding proteins, which fold under reducing conditions, can be generated against virtually all targets. Despite tremendous therapeutic opportunities, intracellular applications are hindered by difficulties associated with achieving cytosolic delivery, compounded by even correctly measuring it. Here, we addressed cytosolic delivery systematically through the development of a biotin ligase-based assay that objectively quantifies cytosolic delivery in a generic fashion. We developed modular transport systems that consist of a designed ankyrin repeat protein (DARPin) for receptor targeting and a different DARPin for intracellular recognition and a bacterial toxin-derived component for cytosolic translocation. We show that both anthrax pores and the translocation domain of Pseudomonas exotoxin A (ETA) efficiently deliver DARPins into the cytosol. We found that the cargo must not exceed a threshold thermodynamic stability for anthrax pores, which can be addressed by engineering, while the ETA pathway does not appear to have this restriction