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International Space Station (international + space_station)

Distribution by Scientific Domains

Life Sciences	60%
Chemistry	30%

Selected Abstracts

Feeding and anhydrobiosis in bdelloid rotifers: a preparatory study for an experiment aboard the International Space Station

INVERTEBRATE BIOLOGY, Issue 4 2004
Claudia Ricci
Abstract. Here we report the effect of food concentration on the recovery from anhydrobiosis of a bdelloid rotifer, Macrotrachela quadricornifera. Cohorts were either starved, or fed high or low concentrations of food, before being dried and their subsequent recovery rates determined. The rotifers starved for 3 d before anhydrobiosis recovered in significantly higher proportion, and those fed lower food concentration recovered better than those fed higher food concentration. In addition, starvation did not decrease the recovery of other bdelloid species (Philodina roseola and Adineta sp. 1) which were either fed or starved before anhydrobiosis. These results suggest that a successful recovery from anhydrobiosis is not dependent on prior resource level supplied to the bdelloids. However, the lack of resources might not be the only factor in a successful recovery from anhydrobiosis. Observations using scanning electron microscopy of fed individuals of M. quadricornifera entering anhydrobiosis showed that some food remained in the digestive tract. Thus, we propose that the negative effect of rich food may be due to a purely mechanical effect and may be interfering with a proper folding of the rotifer body at the onset of anhydrobiosis. This contribution results from studies carried out in preparation for biological experiments scheduled on the International Space Station (ISS). [source]

Gravisensitivity and automorphogenesis of lentil seedling roots grown on board the International Space Station

PHYSIOLOGIA PLANTARUM, Issue 1 2008
Dominique Driss-Ecole
The GRAVI-1 experiment was brought on board the International Space Station by Discovery (December 2006) and carried out in January 2007 in the European Modular Cultivation System facility. For the first run of this experiment, lentil seedlings were hydrated and grown in microgravity for 15 h and then subjected for 13 h 40 min to centrifugal accelerations ranging from 0.29 × 10,2 g to 0.99 × 10,2 g. During the second run, seedlings were grown either for 30 h 30 min in microgravity (this sample was the control) or for 21 h 30 min and then subjected to centrifugal accelerations ranging from 1.2 × 10,2 g to 2.0 × 10,2 g for 9 h. In both cases, root orientation and root curvature were followed by time-lapse photography. Still images were downlinked in near real time to ground Norwegian User Support and Operations Center during the experiment. The position of the root tip and the root curvature were analyzed as a function of time. It has been shown that in microgravity, the embryonic root curved strongly away from the cotyledons (automorphogenesis) and then straightened out slowly from 17 to 30 h following hydration (autotropism). Because of the autotropic straightening of roots in microgravity, their tip was oriented at an angle close to the optimal angle of curvature (120°,135°) for a period of 2 h during centrifugation. Moreover, it has been demonstrated that lentil roots grown in microgravity before stimulation were more sensitive than roots grown in 1 g. In these conditions, the threshold acceleration perceived by these organs was found to be between 0 and 2.0 × 10,3 g and estimated punctually at 1.4 × 10,5 g by using the hyperbolic model for fitting the experimental data and by assuming that autotropism had no or little impact on the gravitropic response. Gravisensing by statoliths should be possible at such a low level of acceleration because the actomyosin system could provide the necessary work to overcome the activation energy for gravisensing. [source]

Crystallization of the collagen-like polypeptide (PPG)10 aboard the International Space Station.

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 10-1 2002

Crystals of the collagen-like polypeptide (PPG)10 were obtained within the Advanced Protein Crystallization Facility on board the International Space Station, during the STS-105/STS-108 mission. The duration of this mission was such to ensure that the crystallization process had reached its end. Crystals were grown both in the presence and in the absence of agarose gel, to compare the quality of the crystals obtained from these different environments. As a result, crystals grown in the absence of agarose on Earth as well as in microgravity showed X-ray diffraction up to 1.15 Å. The intensity/sigma ratio was slightly higher for microgravity grown crystals. Crystals grown in agarose gel, both in microgravity and on ground, showed a comparable diffraction power, with a resolution limit of 1.45 Å. [source]

High-quality crystals of human haematopoietic prostaglandin D synthase with novel inhibitors

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010
Sachiko Takahashi
Human haematopoietic prostaglandin D synthase (H-PGDS; EC 5.3.99.2) produces prostaglandin D2, an allergic and inflammatory mediator, in mast cells and Th2 cells. H-PGDS has been crystallized with novel inhibitors with half-maximal inhibitory concentrations (IC50) in the low nanomolar range by the counter-diffusion method onboard the Russian Service Module on the International Space Station. The X-ray diffraction of a microgravity-grown crystal of H-PGDS complexed with an inhibitor with an IC50 value of 50,nM extended to 1.1,Å resolution at 100,K using SPring-8 synchrotron radiation, which is one of the highest resolutions obtained to date for this protein. [source]

Investigations of a simulated geomagnetic field experienced by the international space station on attentional performance

BIOELECTROMAGNETICS, Issue 1 2009
Cristina Del Seppia
Abstract We have previously reported that the exposure to an abnormal magnetic field simulating the one encountered by the International Space Station (ISS) orbiting around the Earth may enhance autonomic response to emotional stimuli. Here we report the results of the second part of that study which tested whether this field also affects cognitive functions. Twenty-four volunteers participated in the study, 12 exposed to the natural geomagnetic field and 12 to the magnetic field encountered by ISS. The test protocol consisted of a set of eight tests chosen from a computerized test battery for the assessment of attentional performance. The duration of exposure was 90 min. No effect of exposure to ISS magnetic field was observed on attentional performance. Bioelectromagnetics 30:45,51, 2009. © 2008 Wiley-Liss, Inc. [source]

Multimedia satellite communications experiments to the international space station

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 5 2002
Carlo Matarasso
Abstract In the present concept of the International Space Station ISS, it is planned to provide the communication services between the European Columbus module of the ISS and the ground equipment via the TDRS (tracking and data relay satellite) network provided by the American NASA (National Aeronautics and Space Agency). Especially because of its low uplink data rate, an unacceptable limitation of the communication services with Columbus is to be expected. In order to investigate possible improvements to this situation, the MEDIS proposal studies the feasibility of a 150 Mbps full duplex communication system to the Columbus Module on via two MEO satellites. A mixed topology with optical inter satellite links and Ka-band up/down-links shall be employed. Also possible liaisons with the Artemis mission will be considered. The MEDIS project is a collaboration of Astrium GmbH, which is project manager, Bosch SatCom, GMD-Fokus and the German Aerospace Center (DLR). The preparation phase of the project will investigate the concept of the communications infrastructure and the experiments that could be realized when the MEOs are launched. This stage has been completed in February 2001. An additional study phase followed, which will be completed with a presentation in July 2002. Briefly the following aspects have been studied by DLR in the preparation phase: the overall concept of experimental communication services for Columbus, the system requirements and network topology, the relevant protocol and hardware architectures, useful satellite constellations and link scenarios. Two phases could follow the preparation phase, in phase one the satellite will be launched and the link will be tested. In phase two the satellites will be connected to the ISS. Copyright © 2002 John Wiley & Sons, Ltd. [source]