Auswirkungen von anthropogenen Einflüssen auf einen Küstengrundwasserleiter am Beispiel des Ems-Ästuars

Im ostfriesischen Moormerland sind Einflüsse auf einen Küstengrundwasserleiter zu finden. Zum einen wird der Tidefluss Ems durch Ausbaggerungen und den Betrieb des Emssperrwerks bei Gandersum stark bewirtschaftet, zum anderen bewirken das Wasserwerk Tergast in unmittelbarer Umgebung der Ems sowie der durch die Entwässerungsverbände künstlich erniedrigte Grundwasserspiegel ein hydraulisches Gefälle von der Ems hin zum Binnenland. In mehreren Projekten wurden von 1999 bis 2013 die hydrochemische Beschaffenheit und die hydraulischen Bedingungen untersucht, um die zukünftige Entwicklung des Küstengrundwasserleiters abzuschätzen. Mit den Umwelttracern Tritium, Helium-3, Helium-4, Argon-39 und Kohlenstoff-14 konnte nachgewiesen werden, dass die heutige Verteilung von höher und gering mineralisierten Grundwässern das Resultat einer Überprägung des älteren, anthropogen unbeeinflussten Grundwasserströmungsfeldes durch ein jüngeres, anthropogen verändertes Strömungsfeld ist. Modellrechnungen zeigen, dass im Laufe der nächsten Jahrhunderte die Relikte des älteren Strömungsfeldes vollständig durch höher mineralisierte Grundwässer, die der künstlich induzierten Abflussrichtung folgen, überprägt werden.

Time-dependent and somatically acquired mitochondrial DNA mutagenesis and respiratory chain dysfunction in a scleroderma model of lung fibrosis.

Reactive oxygen species (ROS) have been implemented in the etiology of pulmonary fibrosis (PF) in systemic sclerosis. In the bleomycin model, we evaluated the role of acquired mutations in mitochondrial DNA (mtDNA) and respiratory chain defects as a trigger of ROS formation and fibrogenesis. Adult male Wistar rats received a single intratracheal instillation of bleomycin and their lungs were examined at different time points. Ashcroft scores, collagen and TGFβ1 levels documented a delayed onset of PF by day 14. In contrast, increased malon dialdehyde as a marker of ROS formation was detectable as early as 24 hours after bleomycin instillation and continued to increase. At day 7, lung tissue acquired significant amounts of mtDNA deletions, translating into a significant dysfunction of mtDNA-encoded, but not nucleus-encoded respiratory chain subunits. mtDNA deletions and markers of mtDNA-encoded respiratory chain dysfunction significantly correlated with pulmonary TGFβ1 concentrations and predicted PF in a multivariate model.

Binary recombinase systems for high-resolution conditional mutagenesis.

Conditional mutagenesis using Cre recombinase expressed from tissue specific promoters facilitates analyses of gene function and cell lineage tracing. Here, we describe two novel dual-promoter-driven conditional mutagenesis systems designed for greater accuracy and optimal efficiency of recombination. Co-Driver employs a recombinase cascade of Dre and Dre-respondent Cre, which processes loxP-flanked alleles only when both recombinases are expressed in a predetermined temporal sequence. This unique property makes Co-Driver ideal for sequential lineage tracing studies aimed at unraveling the relationships between cellular precursors and mature cell types. Co-InCre was designed for highly efficient intersectional conditional transgenesis. It relies on highly active trans-splicing inteins and promoters with simultaneous transcriptional activity to reconstitute Cre recombinase from two inactive precursor fragments. By generating native Cre, Co-InCre attains recombination rates that exceed all other binary SSR systems evaluated in this study. Both Co-Driver and Co-InCre significantly extend the utility of existing Cre-responsive alleles.

Influence of EMS-physician presence on survival after out-of-hospital cardiopulmonary resuscitation: systematic review and meta-analysis

BACKGROUND Evidence suggests that EMS-physician-guided cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OOHCA) may be associated with improved outcomes, yet randomized controlled trials are not available. The goal of this meta-analysis was to determine the association between EMS-physician- versus paramedic-guided CPR and survival after OOHCA. METHODS AND RESULTS Studies that compared EMS-physician- versus paramedic-guided CPR in OOHCA published until June 2014 were systematically searched in MEDLINE, EMBASE and Cochrane databases. All studies were required to contain survival data. Data on study characteristics, methods, and as well as survival outcomes were extracted. A random-effects model was used for the meta-analysis due to a high degree of heterogeneity among the studies (I (2)  = 44 %). Return of spontaneous circulation [ROSC], survival to hospital admission, and survival to hospital discharge were the outcome measures. Out of 3,385 potentially eligible studies, 14 met the inclusion criteria. In the pooled analysis (n = 126,829), EMS-physician-guided CPR was associated with significantly improved outcomes compared to paramedic-guided CPR: ROSC 36.2 % (95 % confidence interval [CI] 31.0 - 41.7 %) vs. 23.4 % (95 % CI 18.5 - 29.2 %) (pooled odds ratio [OR] 1.89, 95 % CI 1.36 - 2.63, p < 0.001); survival to hospital admission 30.1 % (95 % CI 24.2 - 36.7 %) vs. 19.2 % (95 % CI 12.7 - 28.1 %) (pooled OR 1.78, 95 % CI 0.97 - 3.28, p = 0.06); and survival to discharge 15.1 % (95 % CI 14.6 - 15.7 %) vs. 8.4 % (95 % CI 8.2 - 8.5 %) (pooled OR 2.03, 95 % CI 1.48 - 2.79, p < 0.001). CONCLUSIONS This systematic review suggests that EMS-physician-guided CPR in out-of-hospital cardiac arrest is associated with improved survival outcomes.

Erholungs- und Altersheim für jüdische Lehrer und Kantoren in Bad Ems

A.

Ems et ses environs

par Aloyse Henninger. Traduit de l'Allemand par G. Koell

Use of universal precautions in the workplace: A comparison of two fire /EMS services

The Health Belief Model (HBM) provided the theoretical framework for examining Universal Precautions (UP) compliance factors by Firefighter, EMTs and Paramedics (prehospital care providers). A convenient sample of prehospital care providers (n = 4000) from two cities (Houston and Washington DC), were surveyed to explore the factors related to their decision to comply with Universal Precautions. Eight hundred and sixty-five useable questionnaires were analyzed. The responders were primarily male (95.7%) eight hundred and twenty-eight and thirty-seven were female, prehospital based (100%), EMTs (60.0%) and paramedics (12.8%) who had a mean 13 years of prehospital care experience. ^ Linear regression was used to evaluate the four hypotheses. The first hypothesis evaluating perceived susceptibility and seriousness with reported UP use was statistically significant (p = < .05). Perceived susceptibility, when considered independently, did not make a significant contribution (t = −4.2852; p = 0.0000) to the stated use of Universal precautions. The hypothesis is not supported as stated. The data indicates the opposite effect. Supported is the premise that as perceived susceptibility and perceived seriousness increase the use of Universal Precautions decreases. Hypothesis two tested perceived benefits with internal and external barriers. Both perceived benefits and internal and external barriers as well as the overall regression were significant (F = 112.6, p = 0.0000). The contribution of internal and external barriers was statistically significant (t = 0.0175; p = 0.0000) and (t = 0.0128; p = 0.0000). Hypothesis three which tested modifying factors, cues to action, select demographic variables, and the main effects of the HBM with self reported UP compliance overall was significant. The variables gender, birth, education, job type, EMS certification, years of service, years of experience providing patient care, Universal Precautions training hours, type of apparatus assigned to and the number of EMS related incidents responded to in a month were found to have a significant contribution to the stated use of Universal Precautions. ^ The additive effects were tested by use of a stepwise regression that assessed the contribution of each of the significant variables. Three variables in the equation were statistically significant. Internal barriers (t = −8.5507; p = 0.0000), external barriers (t = −6.2862; p = 0.000) and job type 2 & 3. Job type two (t = −2.8464; p = 0.0045 is titled Engineer/Operator. Job type three (t = −2.5730; p = 0.0103) is titled captain. The overall regression was significant (F = 24.06; p = 0.000). The Hypothesis is supported in the certain demographic variables do influence the stated use of Universal precautions and that as internal and external barriers are decreased, there is an increase in the stated use of Universal Precautions. ^ In summary, this study demonstrated that internal and external barriers have a significant impact on the stated use of Universal Precautions. Internal barriers are those factors within the individual that require an internal change (i.e., forgetfulness, freedom, perception of the urgency of the patient's needs etc.) and external barriers are things in the environment that can be altered (i.e., equipment design, availability of equipment, ease of use). These two model variables explained 23%–30% of the variance. ^

Conversion of cucumber linoleate 13-lipoxygenase to a 9-lipoxygenating species by site-directed mutagenesis

Multiple lipoxygenase sequence alignments and structural modeling of the enzyme/substrate interaction of the cucumber lipid body lipoxygenase suggested histidine 608 as the primary determinant of positional specificity. Replacement of this amino acid by a less-space-filling valine altered the positional specificity of this linoleate 13-lipoxygenase in favor of 9-lipoxygenation. These alterations may be explained by the fact that H608V mutation may demask the positively charged guanidino group of R758, which, in turn, may force an inverse head-to-tail orientation of the fatty acid substrate. The R758L+H608V double mutant exhibited a strongly reduced reaction rate and a random positional specificity. Trilinolein, which lacks free carboxylic groups, was oxygenated to the corresponding (13S)-hydro(pero)xy derivatives by both the wild-type enzyme and the linoleate 9-lipoxygenating H608V mutant. These data indicate the complete conversion of a linoleate 13-lipoxygenase to a 9-lipoxygenating species by a single point mutation. It is hypothesized that H608V exchange may alter the orientation of the substrate at the active site and/or its steric configuration in such a way that a stereospecific dioxygen insertion at C-9 may exclusively take place.

The Escherichia coli SOS mutagenesis proteins UmuD and UmuD′ interact physically with the replicative DNA polymerase

The Escherichia coli umuDC operon is induced in response to replication-blocking DNA lesions as part of the SOS response. UmuD protein then undergoes an RecA-facilitated self-cleavage reaction that removes its N-terminal 24 residues to yield UmuD′. UmuD′, UmuC, RecA, and some form of the E. coli replicative DNA polymerase, DNA polymerase III holoenzyme, function in translesion synthesis, the potentially mutagenic process of replication over otherwise blocking lesions. Furthermore, it has been proposed that, before cleavage, UmuD together with UmuC acts as a DNA damage checkpoint system that regulates the rate of DNA synthesis in response to DNA damage, thereby allowing time for accurate repair to take place. Here we provide direct evidence that both uncleaved UmuD and UmuD′ interact physically with the catalytic, proofreading, and processivity subunits of the E. coli replicative polymerase. Consistent with our model proposing that uncleaved UmuD and UmuD′ promote different events, UmuD and UmuD′ interact differently with DNA polymerase III: whereas uncleaved UmuD interacts more strongly with β than it does with α, UmuD′ interacts more strongly with α than it does with β. We propose that the protein–protein interactions we have characterized are part of a higher-order regulatory system of replication fork management that controls when the umuDC gene products can gain access to the replication fork.

Def1 Promotes the Degradation of Pol3 for Polymerase Exchange to Occur During DNA-Damage–Induced Mutagenesis in Saccharomyces cerevisiae

Funding: Wellcome Trust, 070247/Z/03/A. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Efficient allelic exchange and transposon mutagenesis in Mycobacterium tuberculosis

A better understanding of Mycobacterium tuberculosis virulence mechanisms is highly dependent on the design of efficient mutagenesis systems. A system enabling the positive selection of insertional mutants having lost the delivery vector was developed. It uses ts-sacB vectors, which combine the counterselective properties of the sacB gene and a mycobacterial thermosensitive origin of replication and can therefore be efficiently counterselected on sucrose at 39°C. This methodology allowed the construction of M. tuberculosis transposition mutant libraries. Greater than 106 mutants were obtained, far exceeding the number theoretically required to obtain at least one insertion in every nonessential gene. This system is also efficient for gene exchange mutagenesis as demonstrated with the purC gene: 100% of the selected clones were allelic exchange mutants. Therefore, a single, simple methodology has enabled us to develop powerful mutagenesis systems, the lack of which was a major obstacle to the genetic characterization of M. tuberculosis.