Bruchpunktlokalisation beim Nijmegen Breakage Syndrome

Background and aims: Every somatic cell is continuously threatened by environmentally induced DNA damage. For example the DNA damage may be caused by radiation. This damage can pose an existential danger to the cells. Cells of Nijmegen Breakage Syndrome patients have a limited capability to repair DNA damage due to their defective NBS1 gene. The protein encoded by the NBS1 gene, also called Nbs1, is important for DNA repair and cell cycle control. However its function is reduced in NBS patients. Consequently, NBS patients more frequently suffer from chromosomal instability and cancer. Methods: The aim of this study was to examine whether the DNA of NBS patients is damaged in a pattern that is characteristic for NBS. Chromosomes 1, 2 and 4 from lymphocytes of an NBS patient were selected as representative of the entire genome and analyzed in this study. Non-irradiated lymphocytes and lymphocytes irradiated in vitro with either 0,7 Gy or 2,0 Gy were stained with triple-color FISH. To estimate whether NBS lymphocytes are still able to undergo mitosis as required for analysis by FISH, the mitosis index was determined before performing the FISH staining. Chromosomes were analyzed by fluorescence microscopy. Damaged chromosomes were photographed, the type of aberrations was determined and their localization measured using image analysis software. Results and observations: Comparing the NBS group with controls, three main differences were found: Firstly, the number of chromosomal aberrations was higher in NBS lymphocytes than in control lymphocytes. Secondly, while translocations were the most frequent type of aberration in both NBS and control groups, chromosomal breaks were the second most frequent type in the NBS group as opposed to dicentric chromosomes in the control groups. Finally, characteristic differences were found regarding the localization of aberrations along the chromosomes. The number of chromosomal aberrations in the p telomere-proximal region and in the p arms was markedly lower in the NBS group than in the control groups. On the other hand, the relative frequency of chromosomal aberrations located within the centromere region was three to five times higher in NBS lymphocytes than in control lymphocytes. Within the q arm region, chromosome-specific differences were observed: Aberrations in the central part of the q arm of chromosome 4 occurred only about half as often in NBS lymphocytes as in the control group. However, aberrations in the q telomere-proximal part of chromosome 2 were found about three times as often in NBS as among the control groups. Practical conclusions: The characteristic differences between chromosomal aberrations of NBS and control lymphocytes that were found in this study should enable us to more easily identify NBS patients in the future.Hintergrund und Ziele: Jede Körperzelle ist ständig durch umweltbedingte DNA-Schäden bedroht, wie sie beispielsweise durch Bestrahlung verursacht werden. Diese können eine existenzielle Gefahr für die Zelle darstellen. Zellen von Nijmegen Breakage Syndrome (NBS) Patienten sind auf Grund ihres defekten NBS1-Gens nur eingeschränkt in der Lage diese DNA-Schäden zu reparieren. Ursächlich dafür ist die eingeschränkte Funktionsfähigkeit des vom NBS1-Gen codierten und zur DNA-Reparatur und Zellzykluskontrolle benötigten Proteins Nbs1. Infolgedessen treten bei NBS-Patienten gehäuft Chromosomenschäden und maligne Erkrankungen auf. Ziel dieser Arbeit war es, die Frage zu beantworten, ob die Chromosomenschäden von NBS-Patienten ein für NBS charakteristisches Muster zeigen. Methoden: Exemplarisch für die gesamte DNA wurden die Chromosomen 1, 2 und 4 von Lymphozyten eines NBS-Patienten analysiert. Dazu wurden Zellen unbestrahlt oder nach einer in vitro Bestrahlung mit 0,7 Gy bzw 2,0 Gy im Mitosestadium mittels Fluoreszenz in situ Hybridisierung (FISH) angefärbt. Um abzuschätzen, inwieweit bestrahlte NBS-Lymphozyten noch in der Lage sind, das für die FISH-Färbung notwendige Mitosestadium zu erreichen, ging der FISH-Färbung eine Mitoseindexbestimmung voraus. Unter dem Mikroskop gefundene schadhafte Chromosomen wurden fotografiert und mit einem Bildanalyseprogramm vermessen. Ergebnisse und Beobachtungen: Der Vergleich der NBS-Gruppe mit den Kontrollgruppen zeigte Unterschiede in drei verschiedenen Aspekten: Erstens überstieg die Anzahl der Chromosomenschäden bei Lymphozyten der NBS-Gruppe die in den Kontrollgruppen. Darüber hinaus waren im Gegensatz zu den Kontrollgruppen Chromosomenbrüche in der NBS-Gruppe der zweithäufigste Aberrationstyp nach den Translokationen. Schließlich zeigten sich auch im Bezug auf die Lokalisation der Aberrationen entlang der Chromosomen charakteristische Unterschiede. Der Anteil der Chromosomenaberrationen in den p-telomer-proximalen Abschnitten und in den p-Armen war in NBS-Lymphozyten wesentlich geringer als in den Kontrollgruppen. Dahingegen war die relative Häufigkeit der Chromosomenaberrationen im Zentromerbereich von NBS-Lymphozyten mit 20 bis 30% drei bis fünfmal höher als in den Kontrollgruppen. Im q-Armbereich gab es chromosomenspezifische Unterschiede, da in NBS-Lymphozyten Aberrationen im zentralen Bereich des q-Arms von Chromosom 4 nur etwa halb so häufig vorkamen wie in den Kontrollgruppen. Auf den q-telomer-proximalen Bereich von Chromosom 2 der NBS-Lymphozyten dagegen entfiel ein circa dreimal so großer Anteil an Aberrationen wie in den Kontrollgruppen. Praktische Schlussfolgerungen: An Hand dieser in der vorliegenden Arbeit gefundenen charakteristischen Unterschiede in den Chromosomenaberrationen zwischen NBS-Lymphozyten und den Lymphozyten der Kontrollgruppen sollte in Zukunft eine verbesserte Identifikation von NBS-Patienten möglich sein

Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics

A new regional compilation of seamount-like oceanic igneous features (SOIFs) in the NE Atlantic points to three distinct oceanic areas of abundant seamount clusters. Seamounts on oceanic crust dated 54–50 Ma are formed on smooth oceanic basement, which resulted from high spreading rates and magmatic productivity enhanced by higher than usual mantle plume activity. Late Eocene–Early Miocene SOIF clusters are located close to newly formed tectonic features on rough oceanic crust in the Irminger, Iceland and Norway basins, reflecting an unstable tectonic regime prone to local readjustments of mid-ocean ridge and fracture zone segments accompanied by extra igneous activity. A SOIF population observed on Mid-Miocene–Present rough oceanic basement in the Greenland and Lofoten basins, and on conjugate Kolbeinsey Ridge flanks, coincides with an increase in spreading rate and magmatic productivity. We suggest that both tectonic/kinematic and magmatic triggers produced Mid-Miocene–Present SOIFs, but the Early Miocene westwards ridge relocation may have played a role in delaying SOIF formation south of the Jan Mayen Fracture Zone. We conclude that Iceland plume episodic activity combined with regional changes in relative plate motion led to local mid-ocean ridge readjustments, which enhanced the likelihood of seamount formation

Rauch- und Mehlschwalben: Mitbewohner unserer Gebäude

»Eine Schwalbe macht noch keinen Sommer«, aber sie bringt Leben in oder an das Haus. Leider kennen immer weniger Menschen die lustig schwatzenden Rauchschwalben in Ställen. Auch die Fütterung von jungen Mehlschwalben in ihren Nestern an den Außenseiten von Gebäuden lässt sich immer weniger beobachten. Schwalben brauchen unsere Hilfe. Die reich bebilderte Broschüre gibt Einblick in das interessante Leben der Schwalben. Sie zeigt Möglichkeiten auf, mit welchen meist einfachen Maßnahmen Rauch- und Mehlschwalben unterstützt werden können und wie sich das gemeinsame Wohnen von Mensch und Schwalben unter einem Dach erleichtern lässt. Redaktionsschluss: 13.09.201

An overview of the Upper Paleozoic-Mesozoic stratigraphy of the NE Atlantic region

This study describes the distribution and stratigraphic range of the Upper Paleozoic–Mesozoic succession in the NE Atlantic region, and is correlated between conjugate-margins and along the axis of the NE Atlantic rift system. The stratigraphic framework has yielded important new constraints on the timing and nature of sedimentary basin development in the NE Atlantic, with implications for rifting and the breakup of the Pangaean supercontinent. From a regional perspective, the Permian–Triassic succession records a northward transition from an arid interior to a passively-subsiding, mixed carbonate/siliciclastic shelf margin. A Late Permian–earliest Triassic rift pulse has regional expression in the stratigraphic record. A fragmentary paralic to shallow-marine Lower Jurassic succession reflects Early Jurassic thermal subsidence and mild extensional tectonism; this was interrupted by widespread Mid-Jurassic uplift and erosion, and followed by an intense phase of Late Jurassic rifting in some (but not all) parts of the NE Atlantic region. The Cretaceous succession is dominated by thick basinal-marine deposits, which accumulated within and along a broad zone of extension and subsidence between Rockall and NE Greenland. There is no evidence for a substantive and continuous rift system along the proto-NE Atlantic until the Late Cretaceous

The pre-breakup stratigraphy and petroleum system of the Southern Jan Mayen Ridge revealed by seafloor sampling

The authors would like to acknowledge the contribution from the vessel’s crew (captain I. Rasmussen) and operator (Thor Ltd), the two surveyors (K. Høysæth and H.B. Bortne), and two sampling assistants (F. Gausepohl and A.-M. Voelsch). Sverre Planke and Dougal Jerram are partly funded through a Norwegian Research Council Centers of Excellence project (project number 223272, CEED). Adriano Mazzini is funded by the European Research Council under the European Union's Seventh Framework Programme Grant agreement n° 308126 (LUSI LAB project, PI A. Mazzini). TGS and VBPR funded the cruise and allowed the publication of the data and interpretation. Steve Killops from APT refined our interpretation of the biomarker data. The reviewers and the editor are also thanked for their constructive comments. Finally, this article is dedicated to the biostratigrapher Haavard Selnes who sadly passed away in 2015.Peer reviewedPostprin

Warranty Data Analysis: A Review

Warranty claims and supplementary data contain useful information about product quality and reliability. Analysing such data can therefore be of benefit to manufacturers in identifying early warnings of abnormalities in their products, providing useful information about failure modes to aid design modification, estimating product reliability for deciding on warranty policy and forecasting future warranty claims needed for preparing fiscal plans. In the last two decades, considerable research has been conducted in warranty data analysis (WDA) from several different perspectives. This article attempts to summarise and review the research and developments in WDA with emphasis on models, methods and applications. It concludes with a brief discussion on current practices and possible future trends in WDA