Multiple pathways of plasmid DNA transfer in Helicobacter pylori

Many Helicobacter pylori (Hp) strains carry cryptic plasmids of different size and gene content, the function of which is not well understood. A subgroup of these plasmids (e.g. pHel4, pHel12), contain a mobilisation region, but no cognate type IV secretion system (T4SS) for conjugative transfer. Instead, certain H. pylori strains (e.g. strain P12 carrying plasmid pHel12) can harbour up to four T4SSs in their genome (cag-T4SS, comB, tfs3, tfs4). Here, we show that such indigenous plasmids can be efficiently transferred between H. pylori strains, even in the presence of extracellular DNaseI eliminating natural transformation. Knockout of a plasmid-encoded mobA relaxase gene significantly reduced plasmid DNA transfer in the presence of DNaseI, suggesting a DNA conjugation or mobilisation process. To identify the T4SS involved in this conjugative DNA transfer, each individual T4SS was consecutively deleted from the bacterial chromosome. Using a marker-free counterselectable gene deletion procedure (rpsL counterselection method), a P12 mutant strain was finally obtained with no single T4SS (P12ΔT4SS). Mating experiments using these mutants identified the comB T4SS in the recipient strain as the major mediator of plasmid DNA transfer between H. pylori strains, both in a DNaseI-sensitive (natural transformation) as well as a DNaseI-resistant manner (conjugative transfer). However, transfer of a pHel12::cat plasmid from a P12ΔT4SS donor strain into a P12ΔT4SS recipient strain provided evidence for the existence of a third, T4SS-independent mechanism of DNA transfer. This novel type of plasmid DNA transfer, designated as alternate DNaseI-Resistant (ADR) mechanism, is observed at a rather low frequency under in vitro conditions. Taken together, our study describes for the first time the existence of three distinct pathways of plasmid DNA transfer between H. pylori underscoring the importance of horizontal gene transfer for this species

The transmembrane protein fibrocystin/polyductin regulates cell mechanics and cell motility

Polycystic kidney disease is a disorder that leads to fluid filled cysts that replace normal renal tubes. During the process of cellular development and in the progression of the diseases, fibrocystin can lead to impaired organ formation and even cause organ defects. Besides cellular polarity, mechanical properties play major roles in providing the optimal apical-basal or anterior–posterior symmetry within epithelial cells. A breakdown of the cell symmetry that is usually associated with mechanical property changes and it is known to be essential in many biological processes such as cell migration, polarity and pattern formation especially during development and diseases such as the autosomal recessive cystic kidney disease. Since the breakdown of the cell symmetry can be evoked by several proteins including fibrocystin, we hypothesized that cell mechanics are altered by fibrocystin. However, the effect of fibrocystin on cell migration and cellular mechanical properties is still unclear. In order to explore the function of fibrocystin on cell migration and mechanics, we analyzed fibrocystin knockdown epithelial cells in comparison to fibrocystin control cells. We found that invasiveness of fibrocystin knockdown cells into dense 3D matrices was increased and more efficient compared to control cells. Using optical cell stretching and atomic force microscopy, fibrocystin knockdown cells were more deformable and exhibited weaker cell–matrix as well as cell–cell adhesion forces, respectively. In summary, these findings show that fibrocystin knockdown cells displayed increased 3D matrix invasion through providing increased cellular deformability, decreased cell–matrix and reduced cell–cell adhesion force

Entwicklung eines molekularbiologischen Assays zum Nachweis von Tumormarkern und dessen Integration in ein mikrofluidisches System

Es wurde ein Lab-on-a-Chip-kompatibler, molekularbiologischer Assay für die differentielle Diagnose und das Monitoring einer CML entwickelt. Anschließend wurde der etablierte Assay von der Probenvorbereitung bis zum RT-qPCR-basierten Nachweis in ein Lab-on-a-Chip-System integriert

Elektronisch signierte Dokumente. Anforderungen und Maßnahmen für ihren dauerhaften Erhalt

Die digitale Speicherung von Informationen nimmt in öffentlichen wie privaten Verwaltungen einen immer größeren Stellenwert ein. Daher müssen sich Archive schon frühzeitig an der Implementierung von Dokumentenmanagementsystemen beteiligen, um auch in Zukunft historisch wertvolle digitale Unterlagen an kommende Generationen in authentischer Form weitergeben zu können. Unter dem Titel „Digitales Verwalten - Digitales Archivieren“ veranstaltete das Staatsarchiv Hamburg am 27. und 28. April 2004 die achte Tagung des Arbeitskreises „Archivierung von Unterlagen aus digitalen Systemen“. In ihm sind Archivare aus Staats- und Kommunalarchiven, aus Wirtschafts- und Kirchenarchiven Deutschlands, Österreichs und der Schweiz vertreten. Der archivische Umgang mit digitalen Unterlagen, die Erhaltung der Authentizität und die Langzeitspeicherung elektronischer Signaturen sind die bestimmenden Themen der 16 Beiträge, die in diesem Band dokumentiert sind.Digital storage of information is becoming increasingly important in public and private administration. Archives must therefore participate at an early stage in the implementation of content management systems in order to be able to pass on historically valuable digital documents to future generations in an authentic form. The eighth conference of the working group "Archiving of documents from digital systems" was organised by the Hamburg State Archives on 27 and 28 April 2004 under the title "Digital administration - digital archiving". It includes archivists from state and municipal archives, business and church archives in Germany, Austria and Switzerland. The archival handling of digital documents, the preservation of authenticity and the long-term storage of electronic signatures are the defining themes of the 16 contributions documented in this volume

Keep Me In, Coach: The Short- and Long-Term Effects of Targeted Academic Coaching

To boost college graduation rates, policymakers often advocate for academic supports such as coaching or mentoring. Proactive and intensive coaching interventions are effective, but are costly and difficult to scale. We evaluate a relatively lower-cost group coaching program targeted at first-year college students placed on academic probation. Participants attend a workshop where coaches aim to normalize failure and improve self-confidence. Coaches also facilitate a process whereby participants reflect on their academic difficulties, devise solutions to address their challenges, and create an action plan. Participants then hold a one-time follow-up meeting with their coach or visit a campus resource. Using a difference-in-discontinuity design, we show that the program raises students’ first-year GPA by 14.6 percent of a standard deviation, and decreases the probability of first-year dropout by 8.5 percentage points. Effects are concentrated among lower-income students who also experience a significant increase in the probability of graduating. Finally, using administrative data, we provide the first evidence that coaching/mentoring may have substantial long-run effects, as we document significant gains in lower-income students’ earnings seven to nine years following entry to the university. Our findings indicate that targeted, group coaching can be an effective way to improve marginal students’ academic and early career outcomes

Zero Waste an Schulen in Berlin

ZERO WASTE AN SCHULEN IN BERLIN Zero Waste an Schulen in Berlin / Dorneanu, Stefanie (Rights reserved) (Unterrichtsmaterial