Filtern
Dokumenttyp
- Zeitschriftenartikel (4)
- Beitrag zu einem Tagungsband (1)
- Sonstiges (1)
- Forschungsbericht (1)
Referierte Publikation
- nein (7) (entfernen)
Schlagworte
- Abbildungsverfahren (1)
- Acquired immunodeficiency syndrome (1)
- Amino acid analysis (1)
- Antibody quantification (1)
- Bakterien (1)
- CD4+ cell counting (1)
- E. coli (1)
- ELISA (1)
- Ethanol (1)
- Flow cytometry (1)
Organisationseinheit der BAM
Under the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM). Eleven Metrology Institutes or Designated Institutes and the BIPM participated in the first phase of the pilot study (Part 1). The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. The first phase of the study was designed to employ established methods that had been previously studies by the CCQM Protein Analysis Working Group, involving the digestion of protein down to the peptide or amino acid level. The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to the SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing plays a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification. Amino acid reference values with corresponding expanded uncertainty of 36.10 ± 1.55 mg/kg, 38.75 ± 1.45 mg/kg, 18.46 ± 0.78 mg/kg, 16.20 ± 0.67 mg/kg and 30.61 ± 1.30 mg/kg have been established for leucine, valine, phenylalanine, isoleucine and proline, respectively. Agreement between nearly all laboratories was achieved for the amino acid analysis within 2 to 2.5 %, with one participant achieving markedly higher results due to a technical issue found in their procedure; this result was thus excluded from the reference value calculations. The relatively good agreement within a laboratory between different amino acids was not dissimilar to previous results for peptides or small proteins, indicating that factors such as hydrolysis conditions and calibration procedures could be the largest sources of variability. Peptide reference values with corresponding expanded uncertainty of 4.99 ± 0.28 mg/kg and 6.83 ± 0.65 mg/kg have been established for ALPAPIEK and GPSVFPLAPSSK, respectively. Not surprisingly due to prior knowledge from previous studies on peptide quantitation, agreement between laboratories for the peptide-based analysis was slightly poorer at 3 to 5 %, with one laboratory's result excluded for the peptide GPSVFPLAPSSK. Again, this level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins. To reach the main text of this paper, click on Final Report.
The antimicrobial photodynamic approach has been demonstrated as an efficient and sustainable process for the eradication of microbial pathogens. In this work, silica-coated Magnetite nanoparticles (NPs) were used as carriers of glycosylated porphyrins and phthalocyanines. Their subsequent cationization
resulted in the production of stable antimicrobial photosensitizing materials, effective against E. coli. Suspensions of the photocatalysts in water present bimodal size distributions formed by big clusters and small NPs with hydrodynamic diameters between 8 and 38 nm. The presence of small NPs in the suspensions is related to an effective photodynamic inactivation (PDI) of E. coli cells. Glycosylation of the PS showed a positive effect on the PDI performance, which could be related to a higher accumulation of the photocatalyst over the bacterial cell membrane. In addition, these biocidal agents proved to be photostable and their photoactive performance decreased only between 23% and 28% upon 5 PDI cycles, mostly because of the loss of material between cycles, which makes them promising materials for water disinfection purposes.
Sulfamethoxazol (SMX),a sulfonamide, is a widely used bacteriostatic antibiotic and therefore a promising marker for the entry of anthropogenic Pollution in the environment. SMX is frequently found in wastewater and surface water. This study presents the production of high affinity and selective polyclonal antibodies for SMX and the development and Evaluation of a direct competitive enzyme-linked immunosorbent assay(ELISA)for the quantification of SMX in environmental watersamples. The crystal structures of the cross-reacting compounds sulfamethizole, N4-acetyl-SMX andsuccinimidyl-SMX were determined by x-ray diffraction aiming to explain their high cross-reactivity. These crystal structures are described for the first time. The quantification range of the ELISA is 0.82–63 µg/L. To verify our results, the SMX concentration in 20 environmental samples,including wastewater and surfacewater,was determined by ELISA and tandem mass spectrometry(MS/MS).A good Agreement of the measured SMX concentrations was found with average recoveries of 97–113%for the results of ELISA compared to LC-MS/MS.
A surface-labeled lyophilized lymphocyte (sLL) preparation has been developed using human peripheral blood mononuclear cells prelabeled with a fluorescein isothiocyanate conjugated anti-CD4 monoclonal antibody. The sLL preparation is intended to be used as a reference material for CD4+ cell counting including the development of higher order reference measurement procedures and has been evaluated in the pilot study CCQM-P102. This study was conducted across 16 laboratories from eight countries to assess the ability of participants to quantify the CD4+ cell count of this reference material and to document cross-laboratory variability plus associated measurement uncertainties. Twelve different flow cytometer platforms were evaluated using a standard protocol that included calibration beads used to obtain quantitative measurements of CD4+ T cell counts. There was good overall cross-platform and counting method agreement with a grand mean of the laboratory calculated means of (301.7 ± 4.9) µL-1 CD4+ cells. Excluding outliers, greater than 90% of participant data agreed within ±15%. A major contribution to variation of sLL CD4+ cell counts was tube to tube variation of the calibration beads, amounting to an uncertainty of 3.6%. Variation due to preparative steps equated to an uncertainty of 2.6%. There was no reduction in variability when data files were centrally reanalyzed. Remaining variation was attributed to instrument specific differences. CD4+ cell counts obtained in CCQM-P102 are in excellent agreement and show the robustness of both the measurements and the data analysis and hence the suitability of sLL as a reference material for interlaboratory comparisons and external quality assessment.
Inhalt ist die zerstörungsfreie Detailuntersuchung von Holzbauteilen mit einem dreidimensional abbildenden Ultraschall-Echoverfahren. Das neu entwickelte 3D-Verfahren berücksichtigt den anisotropen Aufbau des Holzes. Die Bildschnitte und Projektionen werden aus flächigen Ultraschallaufnahmen berechnet. Die Messungen erfolgen an Probekörpern sowie an Bauteilen aus der Praxis. In dem Forschungsvorhaben wird die für Holz neue 3D-Rekonstruktionsrechnung verwendet und mit dem Ziel weiterentwickelt, unter Berücksichtigung der anisotropen Struktur des Holzes eine dreidimensional aufgelöste Abbildung von Reflektoren im Inneren der Holzbauteile zu ermöglichen. Damit werden die bisher für Holzbauteile zur Verfügung stehenden Verfahren entscheidend ergänzt, weil nun eine hochgenaue dreidimensionale Abbildung erreichbar ist (Auflösung: 20 mm und besser).
Im Rahmen eines von der Kulturstiftung des Bundes und der Kulturstiftung der Länder geförderten
Projektes zum Erhalt naturkundlicher Nasssammlungen wurden 1) der Zustand der Sammlungen bewertet
(Profiling; Analyse der Vergällungsmittel), 2) über Workshops Expertenwissen in das Projekt gebracht,
3) neue archivbeständige Materialien und Managementmaßnahmen eingeführt (Borosilikat-Gläser und -
Röhrchen, Augenwatte, Tefloneinlagen, Japanpapier, archivbeständige Kleber und Papier, Etikettenaufbewahrung;
digitales Dichtemessgerät, Alcomon-Indikator, Kontrollintervalle), 4) Erhaltungsmaßnahmen
zur langfristigen Konservierung in großem Umfange durchgeführt (Messen der Alkoholkonzentration,
Umsetzen von Präparaten in geeignetere Gefäße, Wiederverschluss von Schaugläsern) und 5) Erfahrungen
und Diskussionsergebnisse zusammengestellt, nicht ohne auf Wissenslücken und wünschenswerte
Forschungsaspekte hinzuweisen. Das Projekt profitierte besonders von der Expertise aus den Materialwissenschaften
und der Papierrestaurierung. Das Museum für Naturkunde Berlin kooperierte eng mit
dem Berliner Medizinhistorischen Museum der Charité, der Zoologischen Staatssammlung München und
dem Forschungsinstitut Senckenberg in Frankfurt. Letzteres Museum führte ein eigenes, themenverwandtes
KUR-Projekt Restauration der Sammlungen 'Vergleichende Anatomie, Embryologie und Histologie'
des Naturmuseums Senckenberg durch.