Prozesscharakterisierung und -optimierung für die Produktion von bioaktiven Naturstoffen mit gleitenden Bakterien

Natural products experience an increasing importance in pharmaceutical research where the development of new lead compounds, especially those with antibiotic activity, has become imperative. The innovation gap left behind by the termination of natural product research in most pharmaceutical companies in the 1990s cannot be filled by chemically synthesized molecules, contrary to the belief of the past decades. In order to reinvigorate natural product development, the potential of so far neglected secondary metabolite producers like gliding bacteria from the order of Myxococcales and the genus Chitinophaga needs to be investigated more thoroughly. This thesis comprises three projects dealing with the development and optimization of fermentation processes for the production of secondary metabolites with antibiotic activity from these gliding bacteria with the aim of increasing their accessibility for further research. The first project covers the production of the anti-MRSA compound family of elansolids by its native producer Chitinophaga sancti Fx7914. The focus was set on the production of elansolid A2, the starting compound for semisynthetical medicinal chemistry approaches. The other important derivative was elansolid C1, which is formed through nucleophilic addition of anthranilic acid directly after biosynthesis. The production of elansolid C1 can thus serve as a model process for precursor-directed biosynthesis with the ultimate goal of facilitating structure-activity-relationship studies. The other two projects deal with the process optimization of the heterologous production of two types of myxobacterial compound classes with the model strain Myxococcus xanthus DK1622. The class of polyketides is represented by the α-pyrone myxopyronin A whereas the non-ribosomal peptide synthetase-derived compounds are represented by the peptolide family of vioprolides. Process optimization was accomplished by improvement of the media composition and process parameters using statistical experiment design, as well as precursor-feeding. These studies lead to the aim of investigating M. xanthus as an expression platform for natural products in general.Naturstoffe erfahren in der heutigen Zeit eine wachsende Bedeutung in der pharmazeutischen Forschung, denn die Entwicklung neuer Leitstrukturen, vor allem jener mit antibiotischer Aktivität, ist zwingend notwendig geworden. Die Innovationslücke, die durch die Beendigung der Naturstoffforschung in den meisten Pharmaunternehmen Ende der 1990er Jahre entstanden ist, kann nicht, anders als lange Jahre angenommen, allein durch rein synthetische Produkte gefüllt werden. Um die Entwicklung neuer Naturstoffe voranzutreiben, muss das Potential bislang vernachlässigter Produzenten von Sekundärmetaboliten, wie denen der Ordnung Myxococcales und der Gattung Chitinophaga, tiefergehend erforscht werden. Diese Arbeit beinhaltet drei Projekte, die sich mit der Entwicklung und Optimierung von Fermentationsprozessen für die Produktion von Sekundärmetaboliten mit antibiotischer Aktivität mithilfe dieser gleitenden Bakterien beschäftigt. Das übergeordnete Ziel hierbei ist es, die Zugänglichkeit dieser Naturstoffe für die weitergehende Forschung zu erhöhen. Das erste Projekt behandelt die Produktion der anti-MRSA Stofffamilie der Elansolide mithilfe ihres natürlichen Produzenten Chitinophaga sancti Fx7914. Der Fokus lag auf der Produktion von Elansolid A2, die Ausgangsverbindung für semisynthetische Medizinalchemie-Ansätze. Das zweite interessante Derivat war Elansolid C1, welches durch die nukleophile Addition von Anthranilsäure im direkten Anschluss an die Biosynthese gebildet wird. Die Produktion von Elansolid C1 dient somit als Modellprozess für die Precursor-gesteuerte Biosynthese, die als übergeordnetes Ziel die Erleichterung der Erforschung von Struktur-Aktivitätsbeziehungen nach sich zieht. Die anderen beiden Projekte beschäftigen sich mit der Prozessoptimierung der heterologen Produktion von zwei verschiedenen Arten myxobakterieller Naturstoffe mit dem Modellorganismus Myxococcus xanthus DK1622. Die Klasse der Polyketide wird durch das α-Pyron Myxopyronin A vertreten, wohingegen die Stoffe, die mithilfe von nicht-ribosomalen Peptidsynthetasen hergestellt werden, durch die Peptolidfamilie der Vioprolide repräsentiert werden. Eine Prozessoptimierung wurde in diesen Projekten durch die Anpassung der Medienzusammensetzung und der Prozessparameter erreicht, bei der sowohl statistische Versuchsplanung als auch Fütterung von Precursoren angewendet wurde. Diese Studien sind Teil der Untersuchung von M. xanthus als heterologe Expressionsplattform für weitere Naturstoffe

The influence of obesity on survival in early, high-risk breast cancer: results from the randomized SUCCESS A trial

Introduction: Obese breast cancer patients have worse prognosis than normal weight patients, but the level at which obesity is prognostically unfavorable is unclear. Methods: This retrospective analysis was performed using data from the SUCCESS A trial, in which 3754 patients with high-risk early breast cancer were randomized to anthracycline- and taxane-based chemotherapy with or without gemcitabine. Patients were classified as underweight/normal weight (body mass index (BMI) < 25.0), overweight (BMI 25.0–29.9), slightly obese (BMI 30.0–34.9), moderately obese (BMI 35.0–39.9) and severely obese (BMI ≥ 40.0), and the effect of BMI on disease-free survival (DFS) and overall survival (OS) was evaluated (median follow-up 65 months). In addition, subgroup analyses were conducted to assess the effect of BMI in luminal A-like, luminal B-like, HER2 (human epidermal growth factor 2)-positive and triple-negative tumors. Results: Multivariate analyses revealed an independent prognostic effect of BMI on DFS (p = 0.001) and OS (p = 0.005). Compared with underweight/normal weight patients, severely obese patients had worse DFS (hazard ratio (HR) 2.70, 95 % confidence interval (CI) 1.71–4.28, p < 0.001) and OS (HR 2.79, 95 % CI 1.63–4.77, p < 0.001), while moderately obese, slightly obese and overweight patients did not differ from underweight/normal weight patients with regard to DFS or OS. Subgroup analyses showed a similar significant effect of BMI on DFS and OS in patients with triple-negative breast cancer (TNBC), but not in patients with other tumor subtypes. Conclusions: Severe obesity (BMI ≥ 40) significantly worsens prognosis in early breast cancer patients, particularly for triple-negative tumors. Trial registration: Clinicaltrials.gov NCT02181101. Registered September 200

Sex-stratified Genome-wide Association Studies Including 270,000 Individuals Show Sexual Dimorphism in Genetic Loci for Anthropometric Traits

Peer reviewe

Optimization of the biotechnological production of a novel class of anti-MRSA antibiotics from Chitinophaga sancti.

Recently, the discovery of the elansolids, a group of macrolides, was reported. The molecules show activity against methicillin-resistant Staphylococcus aureus as well as other gram-positive organisms. This fact renders those substances a promising starting point for future chemical development. The active atropisomers A1/A2 are formed by macrolactonization of the biosynthesis product A3 but are prone to ring opening and subsequent formation of several unwanted side products. Recently it could be shown that addition of different nucleophiles to culture extracts of Chitinophaga sancti enable the formation of new stable elansolid derivatives. Furthermore, addition of such a nucleophile directly into the culture led exclusively to formation of a single active elansolid derivative. Due to low product yields, methods for production of gram amounts of these molecules have to be established to enable further development of this promising compound class

Calendar aging model for lithium-ion batteries considering the influence of cell characterization

To optimize costs and ensure safety, investigation and modeling of battery aging is very important. Calendar aging analysis consist of a periodic sequence of calendar aging and cell characterization. The influence of the characterization on the results of the calendar aging investigation has been assumed to be negligible so far. Nevertheless, the characterization measurements of different studies, especially the important capacity measurement, differ fundamentally. This could have an impact on the results of capacity and resistance change in calendar aging. In this paper, the effect of characterization is quantified for the first time, using periodic characterization measurements. A significant influence in the form of capacity increase and resistance decrease is found. It can be explained by an increase in the active electrode surface area caused by the characterization measurement. Therefore, the cell characterization is a new possible source for capacity increase in calendar aging. As an important result, in future studies capacity measurements should be performed with small currents below 1C to reduce the influence of characterization on the results. Additionally, a correction of the characterization effect can be done according to the presented method

Semi-empirical cyclic aging model for stationary storages based on graphite anode aging mechanisms

Battery life prediction is steadily becoming more relevant due to the increased use of batteries in stationary and mobile applications. Current semi-empirical aging models are often supplemented by empirical model equations and parametrized on the entire available measurement data set. This practice limits their extrapolation capability and transferability. The model in this work describes the two important anode aging mechanisms, solid electrolyte interface (SEI) cracking and reforming and cracking of the active material, by completely physically based equations. A simple incremental capacity analysis (ICA) method is introduced to allow targeted parameterization of the model equations with measurement data, in which the aging modes associated with the respective aging mechanism are present. The overall model can accurately describe the battery capacity loss under dynamic frequency containment reserve loading. It is transferable to all graphite-based battery cell chemistries and provides a basis for future semi-empirical aging models, describing the capacity loss in a wide variety of applications by considering further aging mechanisms

Operating strategy optimization considering battery aging for a sector coupling system providing frequency containment reserve

Battery storage systems are increasingly used in the frequency containment reserve (FCR) application. Coupling the battery with a power-to-heat module can further increase the systems profitability. Different studies optimized the hybrid systems operation by considering country-specific regulations. However, lithium-ion battery aging has not yet been included. This work analyses the impact of system dimension and operation on net present value, considering battery aging. The operation strategy consists of adjusting the target SoE and using the deadband degree of freedom, which allows to suspend provision of FCR for minor frequency deviations. Battery lifetime is simulated using a semi-empirical aging model describing graphite anode aging mechanisms. The highest NPV is obtained with a battery dimension of 0.5Wh/W, 90% target SoE, and normal deadband utilization. For the considered NMC battery cells, deadband utilization contributes to battery lifetime extension when operating at high SoE. Without this cell chemistry-specific lifetime gain, a lower target SoE of 60% and a larger system size of 0.6 is economically more advantageous. In a sensitivity analysis, battery aging was detected as the most crucial parameter influencing system profitability at high FCR prices. The results highlight the importance of including reliable battery aging simulations in future FCR operation optimizations

Gemcitabine as adjuvant chemotherapy in patients with high-risk early breast cancer—results from the randomized phase III SUCCESS-A trial

Background!#!When chemotherapy is indicated in patients with early breast cancer, regimens that contain anthracyclines and taxanes are established standard treatments. Gemcitabine has shown promising effects on the response and prognosis in patients with metastatic breast cancer. The SUCCESS-A trial (NCT02181101) examined the addition of gemcitabine to a standard chemotherapy regimen in high-risk early breast cancer patients.!##!Methods!#!A total of 3754 patients with at least one of the following characteristics were randomly assigned to one of the two treatment arms: nodal positivity, tumor grade 3, age ≤ 35 years, tumor larger than 2 cm, or negative hormone receptor status. The treatment arms received either three cycles of 5-fluorouracil, epirubicin, and cyclophosphamide, followed by three cycles of docetaxel (FEC → Doc); or three cycles of FEC followed by three cycles of docetaxel and gemcitabine (FEC → Doc/Gem). The primary study aim was disease-free survival (DFS), and the main secondary objectives were overall survival (OS) and safety.!##!Results!#!No differences were observed in the 5-year DFS or OS between FEC → Doc and FEC → Doc/Gem. The hazard ratio was 0.93 (95% CI, 0.78 to 1.12; P = 0.47) for DFS and 0.94 (95% CI, 0.74 to 1.19; P = 0.60) for OS. For patients treated with FEC → Doc and FEC → Doc/Gem, the 5-year probabilities of DFS were 86.6% and 87.2%, and the 5-year probabilities of OS were 92.8% and 92.5%, respectively.!##!Conclusion!#!Adding gemcitabine to a standard chemotherapy does not improve the outcomes in patients with high-risk early breast cancer and should therefore not be included in the adjuvant treatment setting.!##!Trial registration!#!Clinicaltrials.gov NCT02181101 and EU Clinical Trials Register EudraCT 2005-000490-21. Registered September 2005