Isolation, biological activity and secondary metabolite investigations of marine-derived fungi and selected host sponges

Higher filamentous fungi were isolated from marine sponges and algae. Their taxonomy, the biological activity of their extracts, their secondary metabolite production, and the biological activity of the obtained pure compounds were investigated. Additionally, selected sponge samples were investigated chemically. Out of 16 sponge samples from six different locations, Australia (Bear Island and The Great Barrier Reef), Dominica (Caribbean), Helgoland (North Sea, Germany), Malta and Tenerife (Spain), 681 fungal strains, representing 53 genera (38 genera of mitosporic fungi, including two clearly obligate marine fungi, 13 genera of Ascomycetes, two genera of Zygomycetes), and 37 strains of Mycelia sterilia, were isolated. Representatives of most of these fungal genera have thus far not been reported from marine sponges. The taxonomy and diversity of the isolated fungal strains suggested, however, that the majority of them were not associated with the host-sponge, but had been simply filtered from the sea water. These isolates were most likely to be mainly terrestrial and facultative marine species. In order to enable preliminary investigations of their biologically active secondary metabolite production, 92 sponge-derived fungal strains were chosen for small scale cultivation on different media. EtOAc extracts of 75 strains (81.5 ) showed antimicrobial activity in agar diffusion assays for antibacterial, antifungal and antialgal activity. Extracts of 27 strains were further tested in different assays: Extracts of six strains showed significant cytotoxicity towards KB cells, and further six exhibited prominent Mycobacterium tuberculosis inhibition. HIV-1 reverse transcriptase was inhibited by extracts of eight strains, and tyrosine kinase (p56lck) by extracts of seven strains.Aus marinen Schwämmen und Algen wurden höhere, myzelbildende Pilze isoliert. Die Taxonomie der Isolate, die biologische Aktivität ihrer Extrakte, ihre Sekundärstoffproduktion und die biologische Aktivität der erhaltene Reinsubstanzen wurden untersucht. Zusätzlich wurden ausgewählte Schwammproben chemisch untersucht. Aus 16 Schwammproben von sechs verschiedenen Herkünften, Australien (Bear Island und Großes Barriere Riff), Dominica (Karibik), Helgoland (Nordsee, Deutschland), Malta und Teneriffa (Spanien), wurden 681 Pilzstämme aus 53 Gattungen isoliert. Diese repräsentierten 38 Gattungen von imperfekten Pilzen, darunter zwei eindeutig obligat marine Arten, 13 Gattungen von Ascomyceten, zwei Gattungen von Zygomyceten und 37 sterile Isolate. Vertreter der meisten dieser Gattungen waren bislang noch nicht aus Schwämmen beschrieben. Die Taxonomie und Diversität der Isolate ließ jedoch vermuten, daß die meisten nicht mit dem jeweiligen Schwamm assoziiert waren, sondern aus dem Meerwasser gefiltert wurden. Diese Isolate bestanden höchstwahrscheinlich aus terrestrischen und fakultativ marinen Arten. Zur Untersuchung der Produktion biologisch aktiver Metaboliten durch die Pilze wurden 92 aus Schwämmen isolierte Stämme in Kleinansätzen auf verschiedenen Medien kultiviert. Ethylacetat Extrakte von 75 Stämmen (81,5 ) zeigten antimikrobielle Wirkung in Agardiffusionstests auf antibakterielle, antifungale und antialgale Wirkung. Extrakte von 27 Stämmen wurden in weiteren Assays getestet. Extrakte von sechs Stämmen waren signifikant zytotoxisch gegen KB Zellen und weitere sechs hemmten Mycobacterium tuberculosis. Die Enzyme HIV-1 Reverse Transkriptase und Tyrosin Kinase (p56lck) wurden von Extrakten von acht bzw. sieben Stämmen gehemmt

Modeling the Flash Rate of Thunderstorms. Part II: Implementation

In Part I of this two-part paper a new method of predicting the total lightning flash rate in thunderstorms was introduced. In this paper, the implementation of this method into the convection-permitting Consortium for Small Scale Modeling (COSMO) model is presented. The new approach is based on a simple theoretical model that consists of a dipole charge structure, which is maintained by a generator current and discharged by lightning and, to a small extent, by a leakage current. This approach yields a set of four predictor variables, which are not amenable to direct observations and consequently need to be parameterized (Part I). Using an algorithm that identifies thunderstorm cells and their properties, this approach is applied to determine the flash frequency of every thunderstorm cell in the model domain. With this information, the number of flashes that are accumulated by each cell and during the interval between the activation of the lightning scheme can be calculated. These flashes are then randomly distributed in time and beneath each cell. The output contains the longitude, the latitude, and the time of occurrence of each simulated discharge. Simulations of real-world scenarios are presented, which are compared to measurements with the lightning detection network, LINET. These comparisons are done on the cloud scale as well as in a mesoscale region composing southern Germany (two cases each). The flash rates of individual cumulonimbus clouds at the extreme ends of the intensity spectrum are realistically simulated. The simulated overall lightning activity over southern Germany is dominated by spatiotemporal displacements of the modeled convective clouds, although the scheme generally reproduces realistic patterns such as coherent lightning swaths

Modeling the Flash Rate of Thunderstorms. Part I: Framework

In this study a straightforward theoretical approach to determining the flash rate in thunderstorms is presented. A two-plate capacitor represents the basic dipole charge structure of a thunderstorm, which is charged by the generator current and discharged by lightning. If the geometry of the capacitor plates, the generator-current density, and the lightning charge are known, and if charging and discharging are in equilibrium, then the flash rate is uniquely determined. To diagnose the flash rate of real-world thunderstorms using this framework, estimates of the required relationships between the predictor variables and observable cloud properties are provided. With these estimates, the flash rate can be parameterized. In previous approaches, the lightning rate has been set linearly proportional to the electrification rate (such as the storm�s generator power or generator current), which implies a constant amount of neutralization by lightning discharges (such as lightning energy or lightning charge). This leads to inconsistencies between these approaches. Within the new framework proposed here, the discharge strength is allowed to vary with storm geometry, which remedies the physical inconsistencies of the previous approaches. The new parameterization is compared with observations using polarimetric radar data and measurements fromthe lightning detection network, LINET. The flash rates of a broad spectrumof discrete thunderstorm cells are accurately diagnosed by the new approach, while the flash rates of mesoscale convective systems are overestimated

A New Lightning Parameterization and its Implementation in a Weather Prediction Model

Based on a straightforward physical model, a new lightning parameterization has been developed: A twoplate capacitor represents the basic dipole charge structure of a thunderstorm, which is charged by the generator current and discharged by lightning. In this approach, the generator current as well as the discharge strength are parameterized using the graupel-mass field. If these two quantities are known, and if the charging and discharging are in equilibrium, then the flash rate is uniquely determined. This approach remedies shortcomings of earlier theoretical approaches that relate the flash rate e.g., to generator power. No distinction is made between intracloud and cloud-to-ground discharges in this approach. In order to test this approach, polarimetric radar data were used, from which the graupel distribution in observed thunderstorms could be inferred. The lightning activity was detected using the LINET network. The comparison between theoretically-predicted and measured flash rates is encouraging: Over a wide range of flash rates, the new approach yields accurate results for isolated thunderstorms. The investigated cases include intense supercellular hailstorms, as well as weak and comparatively shallow storms at the weak end of the spectrum. This approach is compared with an existing approach which is based on the cold cloud depth of the thunderstorm. These approaches were implemented in the convection-resolving model, COSMO-DE. The output includes the time and the geographic location of each simulated discharge. Real-world scenarios were simulated and results will be shown for a severe hailstorm that affected southern Germany in August 2008

The Lightning Imager (LI) on MTG - Scientific studies and developments

The European geostationary meteorological satellite of the third generation (MTG) will carry a lightning imager (LI). This instrument is designed to detect lightning over the whole visible disk under day and night conditions with location accuracy of about 6km at nadir. It will detect the optical radiation from lightning which is emitted from the upper cloud surface. A detection efficiency of 70% for optical pulses of 4µJ/m^2/sr is aimed. Several scientific studies were launched for the preparation of the instrument's operation and the product generation. The outcome of these studies as well as future plans will be presented. An important task was the creation of proxy data sets which serve as input for instrument studies and for the development of the data processing prototype. Two types of proxy data were created: 1. observational data from field experiments in few selected regions in Europe and Africa with the LINET lightning detector. 2. artificial lightning data generated as random data, obeying the distribution functions which were derived from the optical LIS and FORTE observations. It will be demonstrated how the proxy data can be used for the pre-launch study of detection capability of the instrument under various conditions and at the various locations on the field of view. The field of view of the MTG-LI covers Europe and Africa, and parts of South America. It will overlap therefore with the field of view of the geostationary lightning mapper (GLM) on board of the next generation of US weather satellites (GOES-R). The benefit from this coincident observation for data validation and data merging will be discussed

SynUTC—High Precision Time Synchronization over Ethernet Networks

This article describes our SynUTC * (Synchronized Universal Time Coordinated) technology, which enables highaccuracy distribution of GPS time and time synchronization of network nodes connected via standard Ethernet LANs. By means of exchanging data packets in conjunction with moderate hardware support at nodes and switches, an overall worst-case accuracy in the range of some 100 ns can be achieved, with negligible communication overhead. Our technology thus improves the 1 ms-range accuracy achievable by conventional, software-based approaches like NTP by 4 orders of magnitude. Applications can use the high-accuracy global time provided by SynUTC for event timestamping and event generation both at hardware and software level. SynUTC is based upon inserting highly accurate time information into dedicated data packets at the mediaindependent interface (MII) between the physical laye