Cell cultivation under different gravitational loads using a novel random positioning incubator.

Important in biotechnology is the establishment of cell culture methods that reflect the in vivo situation accurately. One approach for reaching this goal is through 3D cell cultivation that mimics tissue or organ structures and functions. We present here a newly designed and constructed random positioning incubator (RPI) that enables 3D cell culture in simulated microgravity (0 g). In addition to growing cells in a weightlessness-like environment, our RPI enables long-duration cell cultivation under various gravitational loads, ranging from close to 0 g to almost 1 g. This allows the study of the mechanotransductional process of cells involved in the conversion of physical forces to an appropriate biochemical response. Gravity is a type of physical force with profound developmental implications in cellular systems as it modulates the resulting signaling cascades as a consequence of mechanical loading. The experiments presented here were conducted on mouse skeletal myoblasts and human lymphocytes, two types of cells that have been shown in the past to be particularly sensitive to changes in gravity. Our novel RPI will expand the horizon at which mechanobiological experiments are conducted. The scientific data gathered may not only improve the sustainment of human life in space, but also lead to the design of alternative countermeasures against diseases related to impaired mechanosensation and downstream signaling processes on earth.

The effect of spaceflight on growth of Ulocladium chartarum colonies on the international space station.

The objectives of this 14 days experiment were to investigate the effect of spaceflight on the growth of Ulocladium chartarum, to study the viability of the aerial and submerged mycelium and to put in evidence changes at the cellular level. U. chartarum was chosen for the spaceflight experiment because it is well known to be involved in biodeterioration of organic and inorganic substrates covered with organic deposits and expected to be a possible contaminant in Spaceships. Colonies grown on the International Space Station (ISS) and on Earth were analysed post-flight. This study clearly indicates that U. chartarum is able to grow under spaceflight conditions developing, as a response, a complex colony morphotype never mentioned previously. We observed that spaceflight reduced the rate of growth of aerial mycelium, but stimulated the growth of submerged mycelium and of new microcolonies. In Spaceships and Space Stations U. chartarum and other fungal species could find a favourable environment to grow invasively unnoticed in the depth of surfaces containing very small amount of substrate, posing a risk factor for biodegradation of structural components, as well as a direct threat for crew health. The colony growth cycle of U. chartarum provides a useful eukaryotic system for the study of fungal growth under spaceflight conditions.

The Rel/NF-κB pathway and transcription of immediate early genes in T cell activation are inhibited by microgravity.

This study tested the hypothesis that transcription of immediate early genes is inhibited in T cells activated in µg. Immunosuppression during spaceflight is a major barrier to safe, long-term human space habitation and travel. The goals of these experiments were to prove that µg was the cause of impaired T cell activation during spaceflight, as well as understand the mechanisms controlling early T cell activation. T cells from four human donors were stimulated with Con A and anti-CD28 on board the ISS. An on-board centrifuge was used to generate a 1g simultaneous control to isolate the effects of µg from other variables of spaceflight. Microarray expression analysis after 1.5 h of activation demonstrated that µg- and 1g-activated T cells had distinct patterns of global gene expression and identified 47 genes that were significantly, differentially down-regulated in µg. Importantly, several key immediate early genes were inhibited in µg. In particular, transactivation of Rel/NF-κB, CREB, and SRF gene targets were down-regulated. Expression of cREL gene targets were significantly inhibited, and transcription of cREL itself was reduced significantly in µg and upon anti-CD3/anti-CD28 stimulation in simulated µg. Analysis of gene connectivity indicated that the TNF pathway is a major early downstream effector pathway inhibited in µg and may lead to ineffective proinflammatory host defenses against infectious pathogens during spaceflight. Results from these experiments indicate that µg was the causative factor for impaired T cell activation during spaceflight by inhibiting transactivation of key immediate early genes.

Space Biology Group: basic research, biotechnology, tissue engineering, and instrument development.

At the beginning of space flight, the investigations were oriented essentially toward the health of the astronauts. But in the last three decades space biology has evolved from "try-and-see" experiments to sophisticated basic and applied research with well-based hypotheses as well as studies on the use of low gravity in biological applications. In 1977 the Space Biology Group of the Swiss Federal Institute of Technology, Zurich, began its activities in space research. A summary of the experiments performed to date, from basic research on the human immune system to the development of sophisticated instruments for biotechnology and medical application, is presented here.

Space bioreactors and their applications.

Space biology is a young and rapidly developing discipline comprising basic research and biotechnology. With the prospect of longer space missions and the construction of the International Space Station several aspects of biotechnology will play a prominent role in space. In fact, biotechnological processes allowing the recycling of vital elements, such as oxygen or water, and the in-flight production of food becomes essential when considering the financial and logistic standpoint. Every kilogram which, having been recycled or produced in space, does not have to be uploaded will drastically reduce the cost of space missions. In addition, the scientific community is offered a better opportunity to investigate long-term biotechnological processes performing experiments with a duration ranging from weeks to months. Therefore, there is an increasing demand for sophisticated instrumentation to satisfy the requirements of future projects in space biology. The carryover of knowledge from conventional bioreactor technology to miniature space bioreactors for a monitored and controlled cell culturing is one of the key elements for this new dimension in space life science. The first space bioreactors were developed and flown at the end of the last century. It has been demonstrated that cells of different types, from bacteria to mammalian cells, can be successfully grown in this type of culture vessel. This chapter presents different generations of bioreactors developed so far, their performances in space and their potential for the future, as well as the activities of the European Space Agency (ESA) in this domain. A dedicated chapter by Lisa Freed on the rotating wall vessel reactor and the latest NASA bioreactor research is also part of this volume.