Evaluating the Quality and Accuracy of TanDEM-X Digital Elevation Models at Archaeological Sites in the Cilician Plain, Turkey

Satellite remote sensing provides a powerful instrument for mapping and monitoring traces of historical settlements and infrastructure, not only in distant areas and crisis regions. It helps archaeologists to embed their findings from field surveys into the broader context of the landscape. With the start of the TanDEM-X mission, spatially explicit 3D-information is available to researchers at an unprecedented resolution worldwide. We examined different experimental TanDEM-X digital elevation models (DEM) that were processed from two different imaging modes (Stripmap/High Resolution Spotlight) using the operational alternating bistatic acquisition mode. The quality and accuracy of the experimental DEM products was compared to other available DEM products and a high precision archaeological field survey. The results indicate the potential of TanDEM-X Stripmap (SM) data for mapping surface elements at regional scale. For the alluvial plain of Cilicia, a suspected palaeochannel could be reconstructed. At the local scale, DEM products from TanDEM-X High Resolution Spotlight (HS) mode were processed at 2 m spatial resolution using a merge of two monostatic/bistatic interferograms. The absolute and relative vertical accuracy of the outcome meet the specification of high resolution elevation data (HRE) standards from the National System for Geospatial Intelligence (NSG) at the HRE20 level.

Elucidation of Nucleic Acid–Drug Interactions by Tandem Mass Spectrometry

In continuation of the long tradition of mass spectrometric research at the University of Bern, our group focuses on the characterization of nucleic acids as therapeutic agents and as drug targets. This article provides a short overview of our recent work on platinated single-stranded and higher-order nucleic acids. Nearly three decades ago the development of soft ionization techniques opened a whole new chapter in the mass spectrometric analysis of not only nucleic acids themselves, but also their interactions with potential drug candidates. In contrast to modern next generation sequencing approaches, though, the goal of the tandem mass spectrometric investigation of nucleic acids is by no means the complete sequencing of genetic DNA, but rather the characterization of short therapeutic and regulatory oligonucleotides and the elucidation of nucleic acid–drug interactions. The influence of cisplatin binding on the gas-phase dissociation of nucleic acids was studied by the means of electrospray ionization tandem mass spectrometry. Experiments on native and modified DNA and RNA oligomers confirmed guanine base pairs as the preferred platination site and laid the basis for the formulation of a gas-phase fragmentation mechanism of platinated oligonucleotides. The study was extended to double stranded DNA and DNA quadruplexes. While duplexes are believed to be the main target of cisplatin in vivo, the recently discovered DNA quadruplexes constitute another promising target for anti-tumor drugs owing to their regulatory functions in the cell cycle.

Electrospray tandem mass spectrometry of mixed-sequence RNA/DNA oligonucleotides

The fragmentation of electrospray-generated multiply deprotonated RNA and mixed-sequence RNA/DNA pentanucleotides upon low-energy collision-induced dissociation (CID) in a hybrid quadrupole time-of-flight mass spectrometer was investigated. The goal of unambiguous sequence identification of mixed-sequence RNA/DNA oligonucleotides requires detailed understanding of the gas-phase dissociation of this class of compounds. The two major dissociation events, base loss and backbone fragmentation, are discussed and the unique fragmentation behavior of oligoribonucleotides is demonstrated. Backbone fragmentation of the all-RNA pentanucleotides is characterized by abundant c-ions and their complementary y-ions as the major sequence-defining fragment ion series. In contrast to the dissociation of oligodeoxyribonucleotides, where backbone fragmentation is initiated by the loss of a nucleobase which subsequently leads to the formation of the w- and [a-base]-ions, backbone dissociation of oligoribonucleotides is essentially decoupled from base loss. The different behavior of RNA and DNA oligonucleotides is related to the presence of the 2'-hydroxyl substituent, which is the only structural alteration between the DNA and RNA pentanucleotides studied. CID of mixed-sequence RNA/DNA pentanucleotides results in a combination of the nucleotide-typical backbone fragmentation products, with abundant w-fragment ions generated by cleavage of the phosphodiester backbone adjacent to the deoxy building blocks, whereas backbone cleavage adjacent to ribonucleotides induces the formation of c- and y-ions. (C) 2002 American Society for Mass Spectrometry.

Tandem Mass Spectrometric Analysis of Metallocene Adducts with Short Oligonucleotides

Metallocene dichlorides constitute a remarkable class of antineoplastic agents that are highly effective against several cancer cell lines. They were shown to accumulate in the DNA-rich region, which suggests DNA as the primary target. These compounds exhibit two cyclopentadienyl ligands and two labile halide ligands, resulting in a bent sandwich structure. The cis-dihalide motif is structurally related to the cis-chloro configuration of cisplatin and similar modes of action can thus be assumed. Cisplatin binds to two neighboring guanine nucleobases in DNA and consequently, distorts the double-helix, thereby inhibiting DNA replication and transcription. Platinum is classified as a soft Lewis acid and binds preferentially to the nitrogen atoms within the nucleobases. The metallocene dichlorides investigated in this study comprise the metal centers Ti, V, Nb, Mo, Hf, and W, which are classified as hard or intermediate Lewis acids, and thus, favor binding to the phosphate oxygen. Although several studies reported adduct formation of metallocene dichlorides with nucleic acids, substantial information about the adduct composition, the binding pattern, and the nucleobase selectivity has not been provided yet. ESI-MS analyses gave evidence for the formation of metallocene adducts (M = Ti, V, Mo, and W) with single-stranded DNA homologues at pH 7. No adducts were formed with Nb and Hf at neutral pH, albeit adducts with Nb were observed at a low pH. MS2 data revealed considerable differences of the adduct compositions. The product ion spectra of DNA adducts with hard Lewis acids (Ti, V) gave evidence for the loss of metallocene ligands and only moderate backbone fragmentation was observed. By contrast, adducts with intermediate Lewis acids (Mo, W) retained the hydroxy ligands. Preliminary results are in good agreement with the Pearson concept and DFT calculations. Since the metallodrugs were not lost upon CID, the nucleobase selectivity, stoichiometry, and binding patterns can be elucidated by means of tandem mass spectrometry.

Increased spread and replication efficiency of Listeria monocytogenes in organotypic brain-slices is related to multilocus variable number of tandem repeat analysis (MLVA) complex.

BACKGROUND Listeria (L.) monocytogenes causes fatal infections in many species including ruminants and humans. In ruminants, rhombencephalitis is the most prevalent form of listeriosis. Using multilocus variable number tandem repeat analysis (MLVA) we recently showed that L. monocytogenes isolates from ruminant rhombencephalitis cases are distributed over three genetic complexes (designated A, B and C). However, the majority of rhombencephalitis strains and virtually all those isolated from cattle cluster in MLVA complex A, indicating that strains of this complex may have increased neurotropism and neurovirulence. The aim of this study was to investigate whether ruminant rhombencephalitis strains have an increased ability to propagate in the bovine hippocampal brain-slice model and can be discriminated from strains of other sources. For this study, forty-seven strains were selected and assayed on brain-slice cultures, a bovine macrophage cell line (BoMac) and a human colorectal adenocarcinoma cell line (Caco-2). They were isolated from ruminant rhombencephalitis cases (n = 21) and other sources including the environment, food, human neurolisteriosis cases and ruminant/human non-encephalitic infection cases (n = 26). RESULTS All but one L. monocytogenes strain replicated in brain slices, irrespectively of the source of the isolate or MLVA complex. The replication of strains from MLVA complex A was increased in hippocampal brain-slice cultures compared to complex C. Immunofluorescence revealed that microglia are the main target cells for L. monocytogenes and that strains from MLVA complex A caused larger infection foci than strains from MLVA complex C. Additionally, they caused larger plaques in BoMac cells, but not CaCo-2 cells. CONCLUSIONS Our brain slice model data shows that all L. monocytogenes strains should be considered potentially neurovirulent. Secondly, encephalitis strains cannot be conclusively discriminated from non-encephalitis strains with the bovine organotypic brain slice model. The data indicates that MLVA complex A strains are particularly adept at establishing encephalitis possibly by virtue of their higher resistance to antibacterial defense mechanisms in microglia cells, the main target of L. monocytogenes.

Schoner Lieder drey : das Erst. Keyn freüd an layd mag mir widerfaren. ...

In Fraktur

Scenenbilder aus Parsifal : Doch, Väterchen, sag' und lehr' uns fein: du kanntest Klingsor, - wie mag das sein?

Signatur des Originals: S 36/F10477

Adam vetus tandem laetus novum promat canticum : Adán de San Víctor y la novedad del canto victorino en la lírica mariana medieval

La poesía latina del maestro Adán de San Víctor (ca.11121192), oriundo de Bretaña y canónigo agustino de la abadía parisina de SaintVictor, representa, en su ámbito y en su época, una novedad trascendente dentro de la lírica litúrgica y particularmente de la lírica mariana. La ductilidad rítmica y retórica del subgénero de la sequentia lograda en sus piezas hace de este autor un paradigma de la creación poética litúrgica en la Europa de los siglos XII y XIII. En este sentido, tanto la mención a su obra como la inclusión de sus sequentiae (junto con otras del mismo período y "estilo" gótico) en diversos manuscritos hispánicos, desde las Cantigas de Santa María hasta el ms. Alcobacense 149, permiten considerar la relevante influencia de esta refinada lírica del siglo XII en la confección de poemas y compilaciones marianas del siglo siguiente en la Península Ibérica.

Adam vetus tandem laetus novum promat canticum : Adán de San Víctor y la novedad del canto victorino en la lírica mariana medieval

La poesía latina del maestro Adán de San Víctor (ca.11121192), oriundo de Bretaña y canónigo agustino de la abadía parisina de SaintVictor, representa, en su ámbito y en su época, una novedad trascendente dentro de la lírica litúrgica y particularmente de la lírica mariana. La ductilidad rítmica y retórica del subgénero de la sequentia lograda en sus piezas hace de este autor un paradigma de la creación poética litúrgica en la Europa de los siglos XII y XIII. En este sentido, tanto la mención a su obra como la inclusión de sus sequentiae (junto con otras del mismo período y "estilo" gótico) en diversos manuscritos hispánicos, desde las Cantigas de Santa María hasta el ms. Alcobacense 149, permiten considerar la relevante influencia de esta refinada lírica del siglo XII en la confección de poemas y compilaciones marianas del siglo siguiente en la Península Ibérica.

Adam vetus tandem laetus novum promat canticum : Adán de San Víctor y la novedad del canto victorino en la lírica mariana medieval

La poesía latina del maestro Adán de San Víctor (ca.11121192), oriundo de Bretaña y canónigo agustino de la abadía parisina de SaintVictor, representa, en su ámbito y en su época, una novedad trascendente dentro de la lírica litúrgica y particularmente de la lírica mariana. La ductilidad rítmica y retórica del subgénero de la sequentia lograda en sus piezas hace de este autor un paradigma de la creación poética litúrgica en la Europa de los siglos XII y XIII. En este sentido, tanto la mención a su obra como la inclusión de sus sequentiae (junto con otras del mismo período y "estilo" gótico) en diversos manuscritos hispánicos, desde las Cantigas de Santa María hasta el ms. Alcobacense 149, permiten considerar la relevante influencia de esta refinada lírica del siglo XII en la confección de poemas y compilaciones marianas del siglo siguiente en la Península Ibérica.