Apoptosis and immune system adaptation in Drosophila melanogaster following space flight and irradiation

Das Leben auf der International Raumstation ISS birgt ständige neue Herausforderung für Astronauten, Wissenschaftler und Techniker. Die Schwerelosigkeit führt bei längeren Aufenthalten im All unter anderem zu Muskelschwund, Knochenabbau und Veränderungen des Flüssigkeitshaushaltes. Das erhöhte Strahlungsniveau in der Erdumlaufbahn und auf interplanetaren Reisen kann zu Krebs und anderen Krankheiten führen, da hier das magnetische Feld der Erde nicht mehr schützend wirkt. Das NASA FIT Projekt – Fungal Pathogenesis, Immunity and Tumorigenesis Studies – bestand aus einem 12-tägigen Space Shuttle Flug mit Drosophila melanogaster Fruchtfliegen, als auch aus Bestrahlungsstudien mit Protonen, um die Auswirkungen dieser Effekte auf zellulärer und genetischer Ebene zu charakterisieren. Das Ziel dieser Arbeit, als Teil des FIT Projekts, war die Beschreibung der Apoptose und Immunsystem Veränderungen nach einem Raumflug beziehungsweise nach Protonenbestrahlung auf der Erde. Es ist bekannt, dass diese zwei zellulären Systeme eng miteinander arbeiten, weshalb Veränderungen durch Weltraumbedingungen durchaus Auswirkungen auf beide Systeme haben können. RT-PCR Genexpressions Studien von Minibrain, Morgue und Wengen, drei Proteine, die sowohl bei Zelltod als auch im Immunsystem wichtige Rollen spielen, zeigten einen ersten Trend zu erhöhter Apoptose Aktivität bei bakteriell infizierten, Space Shuttle geflogen Fliegen im Vergleich zu infizierten Bodenkontrolltieren. Diese Trends wurden auch durch erhöhte Caspase Enzym Aktivität bei den geflogen Tieren bestätigt. Protonen Bestrahlung zeigt einen Anstieg der DNA Fragmentierung, veranschaulicht durch den TUNEL Assay. Weiters wurde gezeigt, dass der Tumor Suppressor p53 in Folge von selbiger Bestrahlung erhöhte Expression zeigt. Phagocytose Aktivität wurde mittels des Alexa Fluor E.coli Phocytose Assays und des Clearance Assays ermittlet, welche beide einen Anstieg der Hemocyten Aktivität als Folge der Bestrahlung.Living and working in space produces new challenges to astronauts, engineers and scientists due to several unique properties of this environment. For instance, weightlessness or microgravity is responsible for reduced exercise of skeletal muscles resulting in muscle atrophy as well as osteoporosis-like bone loss. Away from the Earth’s protective magnetic field, space radiation can damage nucleic acids, cells and tissues resulting in radiation sickness or cancer. The NASA FIT project – Fungal Pathogenesis, Immunity and Tumorigenesis Studies – involved a 12-day Space Shuttle experiment with Drosophila melanogaster flies. Additionally, ground based studies involved the exposure of flies to proton irradiation to investigate the genetic, cellular and behavioural effects. The aims of this project, as part of FIT, were to characterize adaptations of apoptosis and immune system functions following space flight as well as ground based proton radiation exposure. Furthermore, it was of interest if changes in immune system function can be linked to an altered level of apoptosis. RT-PCR gene expression studies of Minibrain, Morgue and Wengen, proteins involved in cell death and immune system functions, showed a trend towards increased apoptotic activity of space flown flies after a bacterial infection in comparison to infected ground control flies. Those trends were also observed by measurement of caspase enzyme activities in space flown animals. Proton irradiation increased fragmentation of DNA in Drosophila hemocytes, which was investigated with the TUNEL assay. Tumor suppressor p53 activation in response to proton treatment was shown with a Drosophila strain containing a p53 radiation response element in front of a GFP protein. Phagocytosis activity was investigated with the Alexa Fluor E.coli Phagocytosis Assay and the Clearance Assay, both showing that high proton irradiation exposure levels can be responsible for an elevated activity level in hemocytes

Biological system development for GraviSat: A new platform for studying photosynthesis and microalgae in space

Microalgae have great potential to be used as part of a regenerative life support system and to facilitate in-situ resource utilization (ISRU) on long-duration human space missions. Little is currently known, however, about microalgal responses to the space environment over long (months) or even short (hours to days) time scales. We describe here the development of biological support subsystems for a prototype “3U” (i.e., three conjoined 10-cm cubes) nanosatellite, called GraviSat, designed to experimentally elucidate the effects of space microgravity and the radiation environment on microalgae and other microorganisms. The GraviSat project comprises the co-development of biological handling-and-support technologies with implementation of integrated measurement hardware for photosynthetic efficiency and physiological activity in support of long-duration (3–12 months) space missions. It supports sample replication in a fully autonomous system that will grow and analyze microalgal cultures in 120μL wells around the circumference of a microfluidic polymer disc; the cultures will be launched while in stasis, then grown in orbit. The disc spins at different rotational velocities to generate a range of artificial gravity levels in space, from microgravity to multiples of Earth gravity. Development of the biological support technologies for GraviSat comprised the screening of more than twenty microalgal strains for various physical, metabolic and biochemical attributes that support prolonged growth in a microfluidic disc, as well as the capacity for reversible metabolic stasis. Hardware development included that necessary to facilitate accurate and precise measurements of physical parameters by optical methods (pulse amplitude modulated fluorometry) and electrochemical sensors (ion-sensitive microelectrodes). Nearly all microalgal strains were biocompatible with nanosatellite materials; however, microalgal growth was rapidly inhibited (~1 week) within sealed microwells that did not include dissolved bicarbonate due to CO2 starvation. Additionally, oxygen production by some microalgae resulted in bubble formation within the wells, which interfered with sensor measurements. Our research achieved prolonged growth periods (\u3e10months) without excess oxygen production using two microalgal strains, Chlorella vulgaris UTEX 29 and Dunaliella bardawil 30.861, by lowering light intensities (2–10μmol photons m−2s−1) and temperature (4–12˚C). Although the experiments described here were performed to develop the GraviSat platform, the results of this study should be useful for the incorporation of microalgae in other satellite payloads with low-volume microfluidic systems

Impact of the AHI1 Gene on the Vulnerability to Schizophrenia: A Case-Control Association Study

BackgroundThe Abelson helper integration-1 (AHI1) gene is required for both cerebellar and cortical development in humans. While the accelerated evolution of AHI1 in the human lineage indicates a role in cognitive (dys)function, a linkage scan in large pedigrees identified AHI1 as a positional candidate for schizophrenia. To further investigate the contribution of AHI1 to the susceptibility of schizophrenia, we evaluated the effect of AHI1 variation on the vulnerability to psychosis in two samples from Spain and Germany.Methodology/Principal Findings29 single-nucleotide polymorphisms (SNPs) located in a genomic region including the AHI1 gene were genotyped in two samples from Spain (280 patients with psychotic disorders; 348 controls) and Germany (247 patients with schizophrenic disorders; 360 controls). Allelic, genotypic and haplotype frequencies were compared between cases and controls in both samples separately, as well as in the combined sample. The effect of genotype on several psychopathological measures (BPRS, KGV, PANSS) assessed in a Spanish subsample was also evaluated. We found several significant associations in the Spanish sample. Particularly, rs7750586 and rs911507, both located upstream of the AHI1 coding region, were found to be associated with schizophrenia in the analysis of genotypic (p = 0.0033, and 0.031, respectively) and allelic frequencies (p = 0.001 in both cases). Moreover, several other risk and protective haplotypes were detected (0.006<p<0.036). Joint analysis also supported the association of rs7750586 and rs911507 with the risk for schizophrenia. The analysis of clinical measures also revealed an effect on symptom severity (minimum P value = 0.0037).Conclusions/SignificanceOur data support, in agreement with previous reports, an effect of AHI1 variation on the susceptibility to schizophrenia in central and southern European populations

Multi-analyte biochip (MAB) based on all-solid-state Ion-selective electrodes (ASSISE) for Physiological Research

Lab-on-a-chip (LOC) applications in environmental, biomedical, agricultural, biological, and spaceflight research require an ion-selective electrode (ISE) that can withstand prolonged storage in complex biological media 1-4. An all-solid-state ion-selective-electrode (ASSISE) is especially attractive for the aforementioned applications. The electrode should have the following favorable characteristics: easy construction, low maintenance, and (potential for) miniaturization, allowing for batch processing. A microfabricated ASSISE intended for quantifying H+ , Ca2+, and CO32- ions was constructed. It consists of a noble-metal electrode layer (i.e. Pt), a transduction layer, and an ion-selective membrane (ISM) layer. The transduction layer functions to transduce the concentration-dependent chemical potential of the ion selective membrane into a measurable electrical signal. The lifetime of an ASSISE is found to depend on maintaining the potential at the conductive layer/membrane interface 5-7. To extend the ASSISE working lifetime and thereby maintain stable potentials at the interfacial layers, we utilized the conductive polymer (CP) poly(3,4-ethylenedioxythiophene) (PEDOT) 7-9 in place of silver/silver chloride (Ag/AgCl) as the transducer layer. We constructed the ASSISE in a lab-ona chip format, which we called the multi-analyte biochip (MAB) (Figure 1). Calibrations in test solutions demonstrated that the MAB can monitor pH (operational range pH 4-9), CO32- (measured range 0.01 mM - 1 mM), and Ca2+ (log-linear range 0.01 mM to 1 mM). The MAB for pH provides a near-Nernstian slope response after almost one month storage in algal medium. The carbonate biochips show a potentiometric profile similar to that of a conventional ion-selective electrode. Physiological measurements were employed to monitor biological activity of the model system, the microalga Chlorella vulgaris. The MAB conveys an advantage in size, versatility, and multiplexed analyte sensing capability, making it applicable to many confined monitoring situations, on Earth or in space