Comparison of the fragmentation behavior of DNA and LNA single strands and duplexes

DNA and locked nucleic acid (LNA) were characterized as single strands, as well as double stranded DNA‐DNA duplexes and DNA‐LNA hybrids using tandem mass spectrometry with collision‐induced dissociation. Additionally, ion mobility spectrometry was carried out on selected species. Oligonucleotide duplexes of different sequences – bearing mismatch positions and abasic sites of complementary DNA 15‐mers – were investigated to unravel general trends in their stability in the gas phase. Single stranded LNA oligonucleotides were also investigated with respect to their gas phase behavior and fragmentation upon collision‐induced dissociation. In contrast to the collision‐induced dissociation of DNA, almost no base loss was observed for LNAs. Here, backbone cleavages were the dominant dissociation pathways. This finding was further underlined by the need for higher activation energies. Base losses from the LNA strand were also absent in fragmentation experiments of the investigated DNA‐LNA hybrid duplexes. While DNA‐DNA duplexes dissociated easily into single stranded fragments, the high stability of DNA‐LNA hybrids resulted in predominant fragmentation of the DNA part rather than the LNA, while base losses were only observed from the DNA single strand of the hybrid

The vegetation of the high peat bogs of Terra del Fuego

Die Vegetation feuerländischer Hochmoore wurde untersucht. Dabei ergaben sich Gemeinsamkeiten und Unterschiede zu den Hochmooren der Nordhalbkugel. Bei den Niedermooren konnte ähnliches aufgezeigt werden. Ein Vergleich der bodenchemischen Ergebnisse bestätigt die vegetationskundlichen Resultate

Zur Bewertung von Bodenverbesserungsmitteln durch Bestimmung von Zersetzungsgrad und Rotte der organischen Substanz Abschlussbericht. Bildband

TIB Hannover: FR 3400(Bil) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Zur Bewertung von Bodenverbesserungsmitteln durch Bestimmung von Zersetzungsgrad und Rotte der organischen Substanz Abschlussbericht. Textband

TIB Hannover: FR 3400(Tex) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Hapten-Specific Single-Cell Selection of Hybridoma Clones by Fluorescence-Activated Cell Sorting for the Generation of Monoclonal Antibodies

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