R04: Innovationen aus dem Ozean

Quorum sensing interfering compounds in the host-microbe interactions of Aurelia aurita
mehr lesen Approximately 71% of the earth surface is covert by oceans where microorganisms can achieve densities of up to 106 per ml of seawater (1) Living as free-living microorganisms or in association with other organisms, e.g. marine animals. Marine animals are hosts to a variety of often specific microorganisms (2,3,4) with still unknown and probably new physiological characteristics (5). These marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations influenced by a variety of ecological conditions and selection pressure. The tissues of marine multicellular organisms act as barriers, at which diverse interactions between microorganisms and host take place. Understanding these interactions might allow using these habitats as a rich source for isolating novel bioactive compounds and genes. Though more than 99% of such bacteria can currently not be cultured using conventional approaches (6) metagenomic and metatranscriptomic strategies try to overcome this bottleneck (7). They enable to analyze the complex genome and genomic information of microbial communities and expression patterns. Microbial consortia on marine multicellular organisms are thus attractive model systems to understand the complex interplay between microbes and their host cells for future medical applications that might be relevant to prevent biofilm formation on surfaces or to address biofouling problems. In addition, it might allow establishing novel strategies to develop specific biomimetic materials, surface microstructure or coatings for medical products.

Investigation of bacterial and fungal communication and secondary metabolites of micro organisms in the sediment of the greenland sea
mehr lesen The focus of my studies will be the communication of micro organisms and the benefits of these communication molecules and secondary metabolites in medical and agricultural applications, mainly the need of new antibiotics to fight multi-resistances and new cytotoxic substances to fight several forms of cancer. The benefit is to find molecules with new forms of application, a less range of adverse side effects and a cheaper alternative of the treatment of cancer with so called biologicals and antibodies.

Surface microstructure and physical properties of fish scales as a basis for biomimetics
mehr lesen In the research program of Future Oceans I would like to apply my experiences on functional microstructures for investigation of surface structures in fishes. Because scale structure and its properties in a large amount of fish species is still unknown, I plan to systematically investigate the scale surfaces of the majority of families of fishes with scanning electron microscopy, 3D white-light interferometry, atomic-force microscopy, μCT in a broad comparative study. After this initial screening of scale microstructure, I will test abrasion resistance of scales and their and drag-reduction characteristics.

Conoidean Peptides - Novel ion channel-targeted peptides from the ocean
Dr. Jie Song,  mehr lesen This study will focus particularly on conotoxins interacting with Kv channels and on new peptides from other conoideans (Turridae, Terebridae). The goal of my research is to characterise these conoidean peptides through tests with voltage-gated potassium channels which can be considered as potential drug targets for the treatment of patients suffering from neurological disease, diabetes mellitus and pain. There are over 40 known human voltage-gated potassium channels, which are directly or indirectly correlated to important physiological functions. Kv1 channels play fundamental roles in repolarisation of membranes and are physiological important within different diseases. Their function can be modulated by conopeptides through different interaction mechanisms. The first step of this research will be concentrated on interaction of κ-conotoxins with Kv1 channels. With this research project I intent to elucidate the structure, function and regulation of interaction between κ-conotoxins and Kv1 channels. The second step of this research will be focused on interaction of other not yet characterised conoidean peptides from Conidae, Turridae or Terebridae with Kv channels. The venoms thereof are regarded as a potential rich and unexplored pharmacological resource. Turridae can be found in the North Sea and the Baltic See. With this study some conoidean peptides from these families will be investigated and evaluated as new potential potassium channel modulators. These peptides will be identified on the base of knowledge and experience from step one.

Insight to the Evolution of Metaorganisms from an ancient Ocean Invader
Prof. Philip Rosenstiel,  mehr lesen Understanding the evolution of metaorganisms, composed of a multicellular host and its associated microbiota, is a fundamental topic in biology and medicine. Basal marine invertebrates allow an insight into the early co-evolution between bacteria and innate immune response machinery. Genetically distinct invasion waves of the ctenophore Mnemiopsis leidyi offer the opportunity to test immune learning and pre-adaptation to associated microbiota in this unexplored phylum. In a common garden experiment ctenophores of different genotypes will be repeatedly exposed to previously known or unknown (novel) bacteria. Expression of immune genes together with microbiota composition after this treatment will be assessed through next generation sequencing. The results will allow new insight into the plasticity of the very basal immune pathways in co-evolution with associated microbiota.

Modelling microalgae cultures to maximise yield
Prof. Andreas Oschlies,  mehr lesen Microalgae are increasingly in the focus of both science and industry for the production of biomass for e.g. biofuels or aquaculture feed, or for extracting valuable substances such as carotenes, vitamins and w-3 fatty acids. An interdisciplinary pilot study is proposed comprising experimentalists and modellers to examine the extent to which yield and stability of algae aquacultures can be improved by means of numerical modelling.

Invasion of Mediterranean mussels into a warming Baltic Sea: will hybridization with local mussels impact emerging aquaculture enterprises?
mehr lesen Recent evidence for the occurence of invasive Mediterranean blue mussels (Mytilus galloprovincialis) in the Baltic Sea1 indicates that in the future, local mussel communities might become a mixture of hybrids between M. galloprovincialis and the native M. edulis x M. trossulus hybrids, particularly when considering future climate change scenarios. As hybridization can affect many ecologically and economically relevant traits, it is paramount to obtain a deeper understanding of the current genetic composition of Baltic Sea mussel populations. We propose to test for reproductive barriers between the three species and to study, whether emerging aquaculture enterprises might be endangered by extensive hybridization of mussels. Hybridization can lead to mussels with reduced shell strength and growth performance, a significant economical problem for mussel aquacultures. We propose to analyze population genetics of local hybrids using next generation transcriptome sequencing and crossing experiments. Further, we propose to measure fitness of generated hybrid offspring under different abiotic conditions, model larval drift to estimate population connectivity in the Baltic Sea and test for performance of hybrids in a local aquaculture enterprise.

The microbiome of Aurelia aurita, friends or foes – coevolved?
Dr. Nancy Weiland-Bräuer,  mehr lesen Marine eukaryotes offer diverse surfaces for attachment and colonization, e. g. mucosa-covered epithelia. Bacteria occurring in the marine environment possess the abilities to colonize these surfaces via biofilm formation or even invasion. Aurelia aurita is an interesting model organism due to its evolutionary age, simple anatomy and existence of different life stages. However, despite a few more general studies, currently no reports on A. aurita associated microbiota or on the holobiont itself are available. A central goal of the proposed project is to compare the role of environment, external disturbance and pathogen challenge for the specificity and functioning of associated microbiota of A. aurita. The associated microbiota of A. aurita will be analyzed by 16S rRNA gene amplicon sequencing comparing different life stages, tissues, lineages and culture conditions. Based on these analyses, the relative effects of the environment and of the host genotype on the establishment and the composition of the respective microbiota will be elucidated. A second major goal addresses whether or not the associated microbiota are involved in host pathogen defense including the mechanisms of signal exchange between host and microbiota and respective interference strategies (quorum quenching). Third, the role of the microbiota for host fitness including life cycle decisions will be analyzed and evaluated to answer questions such as whether high microbial diversity confers a fitness advantage and/or buffers negative effects of environmental stress. Overall the proposed project will allow gaining insight into general and specific hostmicrobe interactions and function of the associated microbiota, as well as evaluating potential coevolution.

The extra‐cellular genetic capacity of marine microbial communities
Dr. Anne Kupczok,  mehr lesen Lateral gene transfer (LGT) is an important mechanism of natural variation in prokaryotes. Here we propose to develop a novel methodology, termed fractionated metagenomics, for the characterization of mobile DNA elements within a given microbial community. Our method will enable the comparison of genetic connectivity features across different environments and within-host microbiota in a cultivation-independent manner. This includes the transferable genetic content, gene transfer mechanisms and the distribution of genetic content among DNA vessels. Applications of our approach to the same microbial community in a time-dependent manner, under similar or varying environmental conditions, will be useful for quantifying spatiotemporal dynamics of genetic connectivity. Our method will be highly useful for researching stress response and adaptation processes of free-living and host-related microbial communities in the changing ocean.

Single cell genomic insights into phytoplankton‐virus interactions
Prof. Ute Hentschel Humeida,  mehr lesen Primary production losses by viruses are about as high as those via grazing (consumption), yet phytoplankton-virus interactions are only poorly understood. Single-cell genomics is one promising new tool to address directly diversity and specificity of such interactions. We will sample Emiliania huxleyi genotypes during phytoplankton blooms that are killed upon attack by Phycodnaviruses. In doing so, we will address viral diversity in E. hux cells in an unbiased approach. Such data are urgently needed to model the ecology of the infection as well as to analyze co-evolutionary patterns, which will ultimately lead to a better understanding of the genomics of viral lysis of phytoplankton blooms.

Regulation of cellular differentiation in sea urchin larvae: a first in vivo model to assay the role of Hedgehog signaling in cancer development
Prof. Ulrich Kunzendorf,  mehr lesen Deregulation of the Hedgehog (Hh) pathway is seen in a variety of human diseases including diabetes, ciliopathies and cancer. In cancer therapy inhibition of pathway components has become an attractive, emerging target for the treatment of malignancies. However, Hh inhibitors showed strong side effects probably due to insufficient specificity of inhibitors, which highlights the need for better models to test Hh modulators in whole animal systems. To date, in vivo models are lacking due to embryonic lethality of vertebrate Hh mutants. Sea urchin larvae are prime developmental model organisms and an excellent and established toolkit is available for molecular perturbations of Hh pathway components. Together with recently developed histological and functional markers for the normal differentiation of ion-regulatory epithelia, sea urchin larvae will be established as a powerful model to improve our understanding of physiology, pathophysiology and pharmacology of the Hh pathway.

Microbial strategies against gas‐hydrate formation
Prof. Klaus Wallmann,  mehr lesen Gas-hydrates form under high pressure - low temperature conditions in the presence of high concentrations of hydrate-forming gases (e.g. CH4, H2S, CO2 or small hydrocarbons) and H2O. In industrial gas production and delivery in pipelines, gashydrates can form rapidly and block even large diameter pipelines, which often leads to dangerous process shutdown. Hence, gas-hydrate inhibition has been a major focus in flow assurance research for many decades [1]. Conventionally, industrial flow assurance relies on adding large amounts of chemicals (~30 vol%) to the pipeline flow (e.g. methanol or ethylene glycol). With upcoming interest in producing natural gas from marine gas-hydrate reservoirs, novel environmentally friendly and sustainable gas-hydrate inhibition strategies are needed. We hypothesize that microorganisms at natural marine oil and gas seeps have developed effective mechanisms inhibiting gas-hydrate formation to avoid being frozen inside a solid gashydrate matrix. These microorganisms have not been described so far, but would be of keen scientific interest not only to better understand microbial activity and diversity at deep sea oil and gas seeps (objective of research topics R03, R07) but also to open a novel way towards establishing a biological, “green” gas-hydrate inhibition technology (research topic R04). We propose to study microbial gas-hydrate inhibition mechanisms in active biomass from sediment samples collected at the Eel River oil and gas seeps in summer 2014 [2]. To address our objectives we will use our high-pressure incubation systems and advanced monitoring strategies, which allow controlled simulation of deep sea seep environments and selective enrichment of relevant microorganisms.

Mathematical modeling and model‐based optimal control and estimation of microalgae growth processes
Prof. Thomas Meurer,  mehr lesen Microalgae have gained increasing focus as a natural resource for biofuels, aquaculture feed, nutrition complements, and cosmetics. Herein, the complex interplay of the algae metabolism with its environment represents a challenge for process control and optimization to maximize yield while minimizing production costs. The objective of this proposal is to overcome this burden by an interdisciplinary approach combining methods from process control and biological insight to develop mathematical models of microalgae growth processes which enable prediction of the culture evolution to address process design, optimal control and state estimation.

Towards novel non‐toxic antifouling surfaces
Prof. Stanislav Gorb,  mehr lesen Marine biofouling is a serious cause of repair and maintenance costs in shipping, and at marine off-shore installations in general. To reduce economic expenses and ecological pressure, environment-friendly antifouling surfaces are urgently required. Within this project we aim at (1) improving previously found foulingrelease surfaces with certain surface microstructures which showed very strong reduction of biofouling under static field trail conditions and (2) to provide strategies to overcome known issues with the applicability of fouling release coatings such as costeffectiveness, durability and processability. For this purpose, preselected antifouling surfaces will be functionalized by different physico-chemical processes to further improve biofouling capabilities which will be evaluated in an already established static field trail setup. To enhance the durability and processability of this surfaces different techniques will be used to replicate those surfaces from different composite materials to allow enhanced resistance to mechanical loads and adhesion to maritime substrates. While continuously exchanging information with key stakeholders a product-near non-toxic antifouling surface prototype is expected.

Seeing is believing ‐ localisation of quorum sensing secondary metabolites on seaweed holobiont by imaging techniques
Prof. Ruth Schmitz-Streit,  mehr lesen This project aims to map spatial localization and identification of quorum sensing (QS) secondary metabolites on the Baltic seaweed Fucus vesiculosus. A combination of three powerful visualization techniques, scanning electron microscopy (SEM), catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) and desorption electrospray ionization mass spectrometry (DESI-MS) imaging will be used to analyze the complex assemblage of surface microbiome and to describe hot spots producing QS metabolites. Secondary metabolites (SMs) of the i. microbial epibiota, ii. epibiont-free algal surface and iii. interior algal tissues will be differentially located and identified by highly sensitive metabolite profiling. The identified phylogenetic information and genetic pathway identification of the surface microbiome will be related to with QS activity and spatial distribution. We aim to pinpoint secondary metabolite locations of F. vesiculosus to shed light into chemical communications between hostmicrobe and potentially intermicrobial interactions on selected seaweed microregions.

Underwater adhesion as a wetting phenomenon: A case study on wetting properties and rheology of barnacle cement
Prof. Martin Wahl,  mehr lesen Wetting is the fundamental requirement to obtain a strong adhesive joint by using glue. Underwater this requirement is a major challenge since water has to be displaced from the surface-glue interface. Many marine organisms use an adhesive for permanent or temporary settlement to living and non-living surfaces and although the chemistry of marine adhesives is relatively well known. The exact physical properties, which dictate the wetting behavior of these adhesives on different substrates have been rarely investigated. Within this project we aim to test, in a case study, the polymerization dynamics of fresh barnacle cement in dependence of various abiotic and biotic factors, as well as its wetting properties of surfaces with well-defined surface energies (different polar and non-polar portion). Using the experimental results obtained the wetting behavior of the cement on different substrates can be modelled and compared to our recent work on antifouling surfaces and to literature data and to design optimized surface textures for strong biofouling reduction. Moreover, this project might help to identify important environmental and biogenic factors, other marine organisms may apply as defense strategies against epibiosis.

Understanding physiological processes to improve animal welfare and production capacity of shrimp aquaculture systems in Schleswig-Holstein
Dr. Marian Hu,  mehr lesen Shrimp aquaculture leaves a tremendous footprint on the coastal zone of many tropical countries (e.g. via deforestation of mangrove ecosystems) and animals are often treated with heavy doses of antibiotics to fight bacterial diseases1. Recently, a recirculating shrimp aquaculture farm has established itself in Kiel that produces animals that are free from antibiotics. However, due to the high stocking densities necessary to operate economically, the system accumulates CO2, which impacts animal physiology and welfare, as well as system productivity. Here, we propose a transdisciplinary approach to investigate how high CO2 experienced in shrimp farms influences animal acid-base status and how this impacts animal behavior, growth performance, shrimp palatability and shrimp susceptibility to bacterial disease. In addition, we propose to characterize the carbonate system dynamics within the shrimp farm in order to develop measures to help stakeholders create carbonate system conditions that increase animal well–being, productivity and product sensory quality at the same time.

Ammonia tolerant, diapausing copepods as model system for hepatic encephalopathy
Prof. Markus Bleich,  mehr lesen Hepathic encephalopathy (HE) is a common and potentially life threatening disease that results from impaired liver function or liver failure. Liver failure causes high plasma ammonia levels, which have been associated with swelling of glial cells (astrocytes), brain edema, and, subsequently, severe neurological damage due to increased intracranial pressure and mortality. While detrimental plasma ammonium levels in mammals typically are <1 mM, recent findings indicate that diapausing copepods accumulate plasma ammonium in excess of 200 mM for months. Owing to similarities in basic central nervous system (CNS) architecture, we believe that understanding mechanisms of high ammonia tolerance in copepods can aid in a better understanding of HE pathophysiology and contribute towards improved disease treatment in humans. We propose to use a range of techniques to characterize ammonia detoxification pathways, brain ultrastructure and brain functional impairment in copepods exposed to high plasma ammonia concentrations. This research is important for understanding diapause biology in copepods, the most important zooplankton group, and will help us learn more about how cells cope with high ammonium concentrations.