(S)-Reutericyclin: Susceptibility Testing and In Vivo Effect on Murine Fecal Microbiome and Volatile Organic Compounds

We aimed to assess the in vitro antimicrobial activity and the in vivo effect on the murine fecal microbiome and volatile organic compound (VOC) profile of (S)-reutericyclin. The antimicrobial activity of (S)-reutericyclin was tested against Clostridium difficile, Listeria monocytogenes, Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Staphylococcus (S.) epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa and Propionibacterium acnes. Reutericyclin or water were gavage fed to male BALBc mice for 7 weeks. Thereafter stool samples underwent 16S based microbiome analysis and VOC analysis by gas chromatography mass spectrometry (GC-MS). (S)-reutericyclin inhibited growth of S. epidermidis only. Oral (S)-reutericyclin treatment caused a trend towards reduced alpha diversity. Beta diversity was significantly influenced by reutericyclin. Linear discriminant analysis Effect Size (LEfSe) analysis showed an increase of Streptococcus and Muribaculum as well as a decrease of butyrate producing Ruminoclostridium, Roseburia and Eubacterium in the reutericyclin group. VOC analysis revealed significant increases of pentane and heptane and decreases of 2,3-butanedione and 2-heptanone in reutericyclin animals. The antimicrobial activity of (S)-reutericyclin differs from reports of (R)-reutericyclin with inhibitory effects on a multitude of Gram-positive bacteria reported in the literature. In vivo (S)-reutericyclin treatment led to a microbiome shift towards dysbiosis and distinct alterations of the fecal VOC profile.     

Solving a combined cutting-stock and lot-sizing problem with a column generating procedure

In NonÅs and Thorstenson [A combined cutting stock and lot sizing problem. European Journal of Operational Research 120(2) (2000) 327–42] a combined cutting-stock and lot-sizing problem is outlined under static and deterministic conditions. In this paper we suggest a new column generating solution procedure for this problem that works well on both small and large-sized problems. The procedure includes characteristics from both the column generating procedure in NonÅs and Thorstenson, which works well on small-sized problems, and from the sequential heuristic due to Haessler [A heuristic programming solution to a nonlinear cutting stock problem, Management Science 17(12) (1971) 793–802], which works well on large-sized problems. Numerical results are presented that show that the new heuristic performs better than both of the earlier procedures. Comparisons with results obtained by other authors indicate that the procedure works well also for the extended cutting-stock problem with only a setup cost for each pattern change.     

The potential of runoff-farming in the Sahel region: Developing a methodology to identify suitable areas

Runoff-farming, a water harvesting technique, is the diversion of rain water from a collecting area to a cropping area, thereby increasing the quantity of water available for crop growth. This technique, applicable in various types, is regarded as necessary to secure and increase food production in semi-arid regions. Simultaneously it minimizes water erosion risk where it is applied. As the potential of runoff-farming has not been investigated, a methodology had to be developed to enable planners to identify suitable areas the most efficient way. Five main information sources are tapped: ground checks by various specialists, maps, data, aerial photographs and satellite images. The interpretation of the collected data yields in the quantification of the runoff water, the water requirements of the crops and the water storage capacity of the soil. All factors have to be validated and integrated into a decision model.     

Development of a hot‐rolled Nb‐bearing Si‐TRIP steel with excellent fatigue behaviour for automotive applications

A hot‐rolled TRIP steel with a tensile strength level above 800 MPa and an excellent fatigue behaviour has been developed with the purpose of satisfying the increasing demands of the automotive industry. Nb was added to the steel to guarantee a stable process and to make the production of the steel possible in a conventional rolling mill. The formation of red scale and the surface quality problems that arise from it have been studied. Additionally, hot torsion tests have been performed in order to validate a new route that could avoid the formation of this red scale allowing the application of the steel for exposed parts (e.g. wheel sector).     

Isolation of COM1, a new gene required to complete meiotic double-strand break-induced recombination in Saccharomyces cerevisiae

We have designed a screen to isolate mutants defective during a specific part of meiotic prophase I of the yeast Saccharomyces cerevisiae. Genes required for the repair of meiotic double-strand breaks or for the separation of recombined chromosomes are targets of this mutant hunt. The specificity is achieved by selecting for mutants that produce viable spores when recombination and reductional segregation are prevented by mutations in SPO11 and SPO13 genes, but fail to yield viable spores during a normal Rec+ meiosis. We have identified and characterized a mutation com1-1, which blocks processing of meiotic double-strand breaks and which interferes with synaptonemal complex formation, homologous pairing and, as a consequence, spore viability after induction of meiotic recombination. The COM1/SAE2 gene was cloned by complementation, and the deletion mutant has a phenotype similar to com1-1, com1/sae2 mutants closely resemble the phenotype of rad50S, as assayed by phase-contrast microscopy for spore formation, physical and genetic analysis of recombination, fluorescence in situ hybridization to quantify homologous pairing and immunofluorescence and electron microscopy to determine the capability to synapse axial elements.     

Lithological and pedological influences on the magnetic susceptibility of soil: their consideration in magnetic pollution mapping

Magnetic susceptibility measurements are widely used to map and monitor the heavy metal pollution of soils. However, the magnetic properties of soils are influenced significantly by the bedrock lithology and soil-forming processes. Therefore, a main challenge in the data interpretation is to filter out the anthropogenic pollution signal. In this study we address this problem by analysing susceptibility values, heavy metal concentrations, as well as pedological parameters in a large soil data set from the eastern segment of Austria, covering a wide range of different lithologies and soil types. The statistic assessment demonstrates an influence of lithology and soil type on the magnetic susceptibility signal. Therefore anomalies are defined in sub sets of different soil types separately. Three different methods were applied to detect susceptibility anomalies: the median absolute deviation method, the boxplot method, and the population modelling method. These methods evaluate topsoil data only and can therefore also be applied to field measurements of magnetic susceptibility. The results were compared to the conventional method of calculating the difference of topsoil and subsoil susceptibility. All three approaches identify the main anomalies in the study area and are successful in circumventing the problem of erroneous anomaly definition due to pedological processes. However, knowledge of the lithological background is still necessary for a meaningful interpretation and can only be substituted by a large amount of data. The tested methods lead to thresholds of different height and therefore act as filters of different strength for the definition of anomalies.     

Dr. Dr. h. c. Kurt Lindner zur Vollendung des 70. Lebensjahres

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