Review and Recommendations for Experimentations in Earth Orbit and Beyond

The space environment is regularly used for experiments addressing astrobiology research goals. The specific conditions prevailing in Earth orbit and beyond, notably the radiative environment (photons and energetic particles) and the possibility to conduct long-duration measurements, have been the main motivations for developing experimental concepts to expose chemical or biological samples to outer space, or to use the reentry of a spacecraft on Earth to simulate the fall of a meteorite. This paper represents an overview of past and current research in astrobiology conducted in Earth orbit and beyond, with a special focus on ESA missions such as Biopan, STONE (on Russian FOTON capsules) and EXPOSE facilities (outside the International Space Station). The future of exposure platforms is discussed, notably how they can be improved for better science return, and how to incorporate the use of small satellites such as those built in cubesat format

RECENT DEVELOPMENT OF A BIOINSPIRED ANTIMICROBIAL SURFACE - A PREVENTIVE TECHNOLOGY FOR EXTENDED STAYS IN CONFINED SPACE ENVIRONMENTS

Challenges of space ight in LEO and exploration activities are manyfold. E.g., the more far away from the Earth, the more increased stays in closed systems (e.g. ISS, lunar and Martian habitats) are a common characteristic. This includes increased but very specific microbial loads caused by high humidity and temperature levels and especially based on the group of humans brought to the closed habitat. Furthermore, there is a higher dependency from biological systems (CELSS) being sensitive against unintended microbial contamination, as well as a need of not transferring microorganisms out of spaceships to outer, habitable bodies and vice versa (COSPAR Planetary Protection Policy). Proven technologies on Earth to counteract microbial contamination as biocides are not a suited alternative for space due to inherent problems of potential toxic effects on non-target organisms, unspecifity and resistancies to some microbial groups. Bioinspired technologies as using antimicrobial peptides from nature (e.g. from frog skin etc.), immobilised on surfaces, are a suited alternative. High exibility concerning the microbial target, low toxicity and an absence of resistancies are the main advantages. An overview about goals and first results of a corresponding activity, funded by ESA, will be given at the symposium

Asymmetrisches Dimethylarginin als kardiovaskulärer Risikofaktor : Transportmechanismen und Auswirkungen einer Akkumulation

Die vorliegende Dissertation beschäftigt sich mit dem Membrantransporter-vermittelten Export von asymmetrischem Dimethyl-L-Arginin (ADMA) aus der Endothelzelle. Da ADMA-Plasmakonzentrationen mit Erkrankungen wie koronaren Herzkrankheiten, Atherosklerose, Bluthochdruck und Endotheldysfunktion in Verbindung gebracht werden, ist ein effektiver ADMA-Export aus der Zelle heraus unabdingbar. Um den Mechanismus hierfür aufzuklären, wurden die immortalisierte Endothelzelllinie EA.hy926 und weitere primäre Endothelzellen (humane Umbilikalvenenendothelzellen und Endothelzellen der großen und kleinen Herzgefäße) auf die Expression basischer Aminosäuretransporter mittels einer qRT-PCR hin untersucht. Dabei zeigte sich, dass alle getesteten Endothelzellen die Aminosäuretransporter hCAT-1, y+LAT1 und y+LAT2 exprimierten. Basierend auf ADMA- Exportdaten, die mit entsprechenden Transporter-überexprimierenden Xenopus laevis-Oozyten gewonnen wurden, wurde festgestellt, dass alle drei Membrantransporter ADMA exportieren konnten. Der physiologisch wichtige Exportweg für intrazellulär anfallendes ADMA scheint dabei der via y+L zu sein, da es sich hierbei um einen aktiven Exportmechanismus handelt, der im Gegentransport von im humanen Plasma reichlich vorhandenen neutralen Aminosäuren und Natriumionen den nach innen gerichteten Natriumgradienten ausnutzt. Die Wichtigkeit des Membrantransportes für die Kontrolle intrazellulärer ADMA-Konzentrationen wurde in vitro durch Entzug von extrazellulären Austauschsubstraten und einer daraus resultierenden Blockade der Transportfunktion gezeigt. Hierbei wurde innerhalb von zwei Stunden ein 2,5-facher Anstieg der intrazellulären ADMA-Konzentration festgestellt, die bei Präsenz von Austauschsubstrat für die Transporter nicht auftrat. Die Relevanz der y+LATs für den ADMA-Export wurde durch Herunterregulation dieser Proteine mittels siRNA sichtbar: Unter diesen Bedingungen konnte ADMA auch in Anwesenheit von Austauschsubstrat für das System y+L weniger effektiv exportiert werden. Eine wichtige Aufgabe des humanen Endothels ist die Bildung bioaktiven Stickstoffmonoxids, das unter anderem eine Vasodilatation der Gefäße bewirkt. Für diese NO-Synthese wird L-Arginin als Substrat von der endothelialen NO-Synthase benötigt. ADMA stellt einen kompetitiven Inhibitor dar, dessen erhöhtes intrazelluläres Vorkommen möglicherweise hemmend auf die NO-Synthase wirken könnte. Es konnten hier allerdings keine Auswirkungen eines um das 4-fache gestiegenen, intrazellulären ADMA-Spiegels auf die Tätigkeit der endothelialen NO-Synthase festgestellt werden. Möglicherweise bedarf es eines noch weiter zu Gunsten des ADMAs verschobenen, intrazellulären L-Arginin:ADMA-Verhältnisses, um eine Hemmung der NO-Synthase festzustellen. Dies könnte bei einem pathologischen Transporterausfall eintreten, der intrazellulär permanent höhere ADMA- Konzentrationen zur Folge hätte. Des Weiteren hätte ein Anstieg der Arginasetätigkeit und damit einhergehend ein Substratdefizit für die NO-Synthase den gleichen Effekt. Der translationale Ansatz mit humanen peripheren mononukleären Blutzellen von Patienten aus der 2. Medizinischen Klinik zeigte die Tendenz einer Korrelation zwischen dem ADMA-Exportvermögen und der Endothelfunktion und brachte zudem die Erkenntnis eines individuell äußerst variablen ADMA-Exportvermögens zutage.The present thesis employs the membrane transporter-mediated export of asymmetric dimethyl-L-arginine (ADMA) out of the endothelial cell. There is an indispensable need for an effective ADMA export as ADMA plasma concentrations are associated with coronary heart diseases, atherosclerosis, high blood pressure and endothelial dysfunction. To elucidate the underlying mechanism, the immortalized endothelial cell line EA.hy926 and other primary endothelial cells (from human umbilical veins and endothelial cells from coronary arteries) were analyzed for the expression of cationic amino acid transporters by qRT-PCR. This showed an endothelial expression of the amino acid transporters hCAT-1, y+LAT1 und y+LAT2. ADMA export data obtained with transporter-overexpressing Xenopus laevis-oocytes revealed ADMA as substrate for all three membrane transporters. The physiologically important export pathway seems to be via y+L because it acts as an active export pump for basic amino acids using the inside-directed sodium gradient to import sodium and neutral amino acids that are more abundant in human plasma. The importance of membrane transport for the control of intracellular ADMA concentrations was showed in vitro by depriving extracellular exchange substrates which caused a blockade of transporter function. This resulted in a 2.5-fold increase of the intracellular ADMA concentration in two hours that was not detected under presence of exchange substrate. The relevance of the y+LATs for the ADMA export became apparent after down-regulation of the protein by means of siRNA: under this condition ADMA was exported less effective even in the presence of exchange substrate. One important function of human endothelium is the production of bioactive nitric oxide that causes a vasodilation of the vessels among other things. The endothelial NO-synthase uses L-arginine as substrate for this NO synthesis. ADMA represents a competitive inhibitor and an increased intracellular occurrence could possibly inhibit the NO synthesis. Yet a 4-fold increased intracellular ADMA level did not affect NO-synthase activity. Potentially a less pronounced intracellular L-arginine:ADMA-relation is necessary to determine an inhibited NO-synthase activity. This could occur with a pathological transporter failure which would entail in permanently increased intracellular ADMA concentrations. Furthermore, an increased arginase activity along with a substrate deficit would have the same effect. The translational approach with human peripheral blood mononuclear cells from patients from the 2nd Medical Clinic tended to show a correlation between ADMA export activity and endothelial function. In addition, the pilot study showed that ADMA export activity is individually variable

Fundamental of Space Biology : Research on Cells animals and Plants in Space

xviii,375 hal,;ill,;23 c

Fundamentals of Space Biology. Research on Cells, Animals, and Plants in Space

This book is intended as an overview at an undergraduate or early university level and describes the effects of spaceflight at cellular and organism levels. Past, current, and future research on the effects of gravity - or its absence - and ionizing radiation on the evolution, development, and function of living organisms is presented in layman's terms by researchers who have been active in this field. The purpose is to enlighten science and non-science readers to the benefits of space biology research for conducting basic and applied research to support human exploration of space and to take advantage of the space environment as a laboratory for scientific, technological, and commercial research. The first chapters present an overview of the major focuses of space research in biology, as well as the history and the list of animals and plants that have flown in space to date. The following chapters describe the main results of space studies in gravitational biology, developmental biology, radiation biology, and biotechnology. A background is given in each chapter, so that a minimum of prior coursework in biology is necessary for full comprehension. Each chapter also includes perspectives for future research and a list of references

Salicornia L. (Amaranthaceae) in South Africa and Namibia: rapid spread and ecological diversification of cryptic species

In Salicornia, morphology does not provide reliable diagnostic characters supporting the true extent of evolutionary divergence in the genus, and species concepts have been challenged by molecular analyses. Here, we report the results of an analysis of 91 accessions of the S.?meyeriana complex from South Africa and Namibia using the measurements of 38 morphological traits and external transcribed spacer (ETS) sequence data. Morphological data were analysed using discriminant analysis, principal coordinate analysis and nonmetric multidimensional scaling. Phylogenetic divergence was compared with the geographical and ecological diversity of the sampled populations. Tree topology corresponds to geography and ecology, but not to morphology. Most clades have distinct distribution areas and ecological profiles related to tidal, supratidal or inland saline habitats. Salicornia probably diversified in habitats that have experienced regular fragmentation by marine transgression/regression cycles during the Pleistocene. We suggest that this radiation produced young, but genetically, geographically and ecologically well-defined lineages. The lack of morphological signal reveals the existence of cryptic species in Salicornia and demonstrates the necessity of using molecular data to define taxa in this genus. We propose the recognition of two subspecies in the S.?meyeriana complex: S.?meyeriana subsp. meyeriana and S.?meyeriana subsp. knysnaensis. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 175–186