Influence of vitamin B12 and light on the formation of chlorosomes in green- and brown-colored Chlorobium species

The specific Bchl a and c content of the vitamin B12-dependent Chlorobium limicola strain 1230 decreased strongly under vitamin B12 limitation. In comparison to a regularly grown culture (20 g vitamin B12/l) the specific Bchl c content of a B12-limited culture was reduced to 20% and the specific Bchl a content to 42%. By ultrathin sections it could be clearly demonstrated that B12-deficient cells contained no chlorosomes. After the addition of vitamin B12 to a deficient culture, chlorosomes were formed and the Bchl a and c content increased again to the level of regularly grown cells. The brown-colored Chlorobium phaeobacteroides strain 2430 (type strain) and the extremely low-light-adapted strain MN1 were compared with respect to the influence of light on the formation of chlorosomes and the Bchl e and carotenoid content. By ultrathin sections it could be demonstrated that strain MN1 produced two-fold larger chlorosomes. Chlorosome dimensions of strain MN1 decreased with increasing light intensities. The number of chlorosomes per cell in both strains did not change with different light intensities. Strain MN1 formed twice as much Bchl e as the type strain when grown at 30 or below 1 mol · m-2 · s-1. Under comparable light conditions strain MN1 formed 14–57% more carotenoids than the type strain. Low light intensities aaused the carotenoid content to increase by 25% in strain 2430 in comparison to high light intensity

An online NP-HPLC-DPPH method for the determination of the antioxidant activity of condensed polyphenols in cocoa

In PressUnroasted cocoa beans are rich in monomeric flavanols and particularly epicatechin-based proanthocyanidin oligomers, with the latter making up to 60% of the total polyphenol content. Although the antioxidant activity of cocoa polyphenols is well known, it is still a challenging analytical field, especially, when it comes to the determination of condensed polyphenols and the evaluation of their single contribution to the overall activity. Therefore, an online NP-HPLC-DPPH assay was developed to separate the homologous series of condensed polyphenols for assessing their antioxidant capacity in relation to their degree of polymerization (DP), simultaneously. In this context, normal-phase chromatography allows separation of polyphenols based on their degree of polymerization. This study showed that an unroasted cocoa extract contains condensed polyphenols with a DP of up to 10 monomer units. By means of the online post-column derivatisation with 2,2-diphenyl-1-picrylhydrazyl (DPPH), the antioxidant capacity of the separated condensed polyphenols was assessed. It could be shown that, with the exception of the dimers, the contribution to the total antioxidant activity decreased from monomers to decamers. However, from the single proanthocyanidins identified, nonameric and decameric proanthocyanidins were found to have the highest values for the antioxidant capacity. The degree of polymerization associated with each molecular weight fraction was further confirmed using electrospray ionization mass spectrometry coupled with reverse-phase liquid chromatography. The online NP-HPLC-DPPH method can be used as qualitative and quantitative analysis of condensed proanthocyanidins and the simultaneous elucidation of the biological activity of proanthocyanidins in complex mixtures

A DAI approach to modeling the transportation domain

A central problem in the study of autonomous cooperating systems is that of how to establish mechanisms for controlling the interactions between different parts (which are called agents) of the system. One way to integrate such mechanisms into a multi-agent system is to exploit the technique of cooperation or negotiation protocols. In a protocol we distinguish to essential layers: the communication layer specifying the possible flow of messages between different agents, and the decision layer, which controls the selection of a message (speech-act) that the agent sends in a specific situation. In this report we first give a short introduction of our agent model InteRRap which provides the basis for the modeling of the different scenarios considered in the AKA-Mod project at the DFKI. The techniques we will discuss in the following are located in the plan based component and in the cooperation component of this model. The domain of application is the MARS scenario (Modeling a Multi-Agent Scenario for Shipping Companies) which implements a group of shipping companies whose goal it is to deliver a set of dynamically given orders, satisfying a set of given time and/or cost constraints. The complexity of the orders may exceed the capacities of a single company. Therefore, cooperation between companies is required in order to achieve the goal in a satisfactory way. This domain is of considerable interest for studies with economical background as well as for research projects. We give a short summary of results from economical studies that are concerned with the real-world situation in Germany in the transportation domain. They show the need for the development of new techniques from the field of computer science to tackle the problems therein. Then, an overview on related research is presented. Two approaches are discussed in more detail: the first one being based on OR-techniques and a second one being based on the concept of partial intelligent agents attempting to integrate techniques from OR and DAI. Both approaches are concerned with the situation in a single company. However, our purpose to handle the case of distributed shipping companies requires additional mechanisms, e.g. to cope with the problems of task allocation and task decomposition in multi-agent systems. Mechanisms for distributed task decomposition and task allocation processes in multi-agent systems belong to the core of our studies. Therefore, we will first discuss techniques for these problems in a general setting and then describe their implementations in the MARS system. In this description, particular emphasis is placed on the cooperation within a shipping company. Here, one company agent has to allocate a set of orders its truck agents. The truck agents support the company agents by giving cost estimations based on their route planning facility. Thus, this procedure provides the basis for the decisions of the company agents and is discussed in very detail. Finally, we present results from a series of benchmark tests. The test sets have also been run with OR-implementations and thus, give us the opportunity to compare our implementation against these approaches

Localization of Wolbachia-like gene transcripts and peptides in adult Onchocerca flexuosa worms indicates tissue specific expression

BACKGROUND: Most filarial species in the genus Onchocerca depend on Wolbachia endobacteria to successfully carry out their life cycle. O. flexuosa is a Wolbachia-free species, but its genome contains Wolbachia-like sequences presumably obtained from Wolbachia via horizontal gene transfer. Proteogenomic studies have shown that many of these Wolbachia-like sequences are expressed in adult worms. METHODS: Six Wolbachia-like sequences in O. flexuosa were chosen for further study based on their sequence conservation with Wolbachia genes, length of predicted open reading frames, and expression at the RNA and/or protein levels. In situ hybridization and immunohistochemical labeling were used to localize Wolbachia-like transcripts and peptides in adult worm tissues. RESULTS: RNA probes representing three of the six target sequences produced hybridization signals in worm tissues. These probes bound to transcripts in the intestine and lateral chords of both sexes, in the hypodermis, median chords and uteri in females, and in sperm precursor cells in males. Antibodies raised to three peptides corresponding to these transcripts bound to specific bands in a soluble extract of adult O. flexuosa by Western blot that were not labeled by control antibodies in pre-immune serum. Two of the three antibodies produced labeling patterns in adult worm sections that were similar to those of the RNA probes, while the third produced a different pattern. CONCLUSIONS: A subset of the Wolbachia-like sequences present in the genome of the Wolbachia-free filarial species O. flexuosa are transcribed in tissues where Wolbachia reside in infected filarial species. Some of the peptides and/or proteins derived from these transcripts appear to be concentrated in the same tissues while others may be exported to other regions of the worm. These results suggest that horizontally transferred Wolbachia genes and gene products may replicate important Wolbachia functions in uninfected filarial worms

Block Crossings in Storyline Visualizations

Storyline visualizations help visualize encounters of the characters in a story over time. Each character is represented by an x-monotone curve that goes from left to right. A meeting is represented by having the characters that participate in the meeting run close together for some time. In order to keep the visual complexity low, rather than just minimizing pairwise crossings of curves, we propose to count block crossings, that is, pairs of intersecting bundles of lines. Our main results are as follows. We show that minimizing the number of block crossings is NP-hard, and we develop, for meetings of bounded size, a constant-factor approximation. We also present two fixed-parameter algorithms and, for meetings of size 2, a greedy heuristic that we evaluate experimentally.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

Entrepreneurship as catalyst for sustainable development : opening the black box

In the last decades, sustainable development has become an important topic of discussion for scholars and practitioners concerned with environmental issues. Since the publication of the Brundtland Report, which represents a milestone in triggering awareness for sustainability issues, sustainable development has steadily gained popularity to become one of the most important environmental discourses today. Together with innovation, the United Nations identified entrepreneurship as a key element for addressing sustainable development challenges. Due to its growing recognition as a driver of sustainable development, entrepreneurship is subject to research across many scientific disciplines. To systemize the current state of knowledge, the purpose of this paper is to systematically review recent literature and to outline how sustainable development influences entrepreneurial activities and vice versa. In addition, it investigates whether and under what circumstances entrepreneurship can contribute to the economic, environmental and social dimension of sustainable development. The systematic literature review shows that several research areas, such as opportunities, motivations, competencies, strategies and business models of sustainability-oriented entrepreneurs, have already received wide coverage by academic literature. However, our knowledge about how entrepreneurial activities contribute to the achievement of the United Nations sustainable development goals is still limited and should be addressed by further research

Metal-Organic Frameworks in Germany: from Synthesis to Function

Metal-organic frameworks (MOFs) are constructed from a combination of inorganic and organic units to produce materials which display high porosity, among other unique and exciting properties. MOFs have shown promise in many wide-ranging applications, such as catalysis and gas separations. In this review, we highlight MOF research conducted by Germany-based research groups. Specifically, we feature approaches for the synthesis of new MOFs, high-throughput MOF production, advanced characterization methods and examples of advanced functions and properties

Los cementerios en Europa como lugares de recuerdo y paisajes de la memoria

European cemeteries have been places of remembrance for centuries. With their spatial structure, their sepulchral monuments and buildings, they report on the changing ways of dealing with the deceased. The burial sites give a materialized expression to the feeling of mourning, the change of which in the course of history is able to show the manifold interrelationships between death, society and memory. They store biographies, mentalities, ideologies, gender relations, social structures and hierarchies as well as regional historical specifics. Cemeteries are classical memory landscapes, as will be explained using the example of European cemeteries in the bourgeois era –also under political aspects–, military cemeteries and special maritime cemeteries of the North Sea coast.Los cementerios europeos han sido lugares de recuerdo durante siglos. Con su estructura espacial, sus monumentos y sus edificios funerarios nos informan sobre los modos cambiantes de tratar con los difuntos. Los lugares de enterramiento muestran una expresión material del sentimiento de duelo, cuyo cambio a lo largo de la historia es capaz de mostrar las múltiples interrelaciones entre muerte, sociedad y memoria. Reúnen biografías, mentalidades, ideología, relaciones de genero, estructuras y jerarquías sociales, así como elementos históricos regionales. Los cementerios son paisajes clásicos de la memoria, como ilustra el ejemplo de los cementerios europeos de época burguesa –también en aspectos políticos–, los cementerios militares y los cementerios marítimos especiales de la costa del Mar del Norte