Fertilization in Microgravity

During the 15 days of the second International Microgravity Laboratory mission (IML-2, STS-65), natural mating of male and female vertebrates occurred in microgravity and was videotaped for the first time. The Japanese Medaka fish Oryzias latipes mated successfully in space and young fish hatched during the flight (Figure 5-02). Back on the ground, the offspring produced healthy second-generation (F2) animals (Ijiri 1998). Years before this video-based demonstration of successful fish mating in...

The Clinostat as a Tool for Studying Gravisensitivity

The clinostat has been used for a century to simulate microgravity. It could be considered as a good tool for the analysis of gravisensing if (at least) it had the same effects as microgravity on the statolith apparatus, i.e., if the volume of the statoliths, their density, and their distribution in the statocytes were similar in both culture conditions. Some analyses were performed to compare the effects of microgravity and clinostats. However, these studies were carried out on different...

Perception of Gravity in Plants

Experimentally, the gravitropic response can be studied by growing a seedling in the vertical position (the root tip down) and then placing the root in the horizontal position. The root is then subjected to gravistimulation. In this case, its extremity bends downward in order to recover its normal direction of growth (Figure 6-02). The curvature is due to a differential growth in the upper and lower halves of this organ. It is generally accepted (Perbal and Driss-Ecole 2003) that the...

Muscle and Bone Development

The impact of microgravity on muscle and skeleton development was mainly studied in rats. These organs are formed from the mesoderm and its cellblocks, the somites. Main features of somite formation are periodicity, epithelialization, specification, and differentiation. Cells of the somites are precursors for a. The cartilage of the vertebrates and ribs b. The muscles of the rib cage, limbs, abdominal wall, back, and tongue c. The dermis of the dorsal skin depending on the site within the The...

Role of Meristems in the Plant Development

Plants are unique multicellular organisms that possess the capacity for unlimited growth throughout their lives. This potentiality is due to stem cells (Laux 2003, Byrne et al. 2003) located within meristems (Figure 6-14, inserts). Stem cells perpetuate themselves by cell division and give rise to derivatives that differentiate to form tissues. This results in a repeated initiation of new organs throughout the plant life. Plant meristems are classified on the basis of their location and...

Biotechnology In Space

' Centre National de la Recherche Scientifique, Toulouse, France 2 Ohio University, Athens, Ohio, USA Often praised as the most promising field for the commercial exploitation of space, this domain today has two primary fundamental aspects the use of microgravity as a tool for separation processes and techniques (including protein crystals growth), and the production of cells for medically valuable proteins like immuno-reactive molecules, hormones, enzymes, and vaccines. Results of space...

Spaceflight History

Since the beginning of aeronautics and space exploration, animals have accompanied and sometimes preceded humans as space travelers. Historically, extensive animal experimentation was used in both the United States and Soviet Russian space programs to collect the medical knowledge and test the engineering design concepts that would be required to support human spaceflight. A variety of animal models were used as substitutes to test the suitability of the space environment for human presence,...

Summary And Conclusions

Since the first supposition of the existence of ionizing radiation originating from outer space at the beginning of the last century, a lot of work has been done in order to characterize the radiation field surrounding the Earth. A series of experiments has been initiated on the various components of cosmic radiation, their radiobiological importance, and the role of the other spaceflight factors in radiobiological processes. Besides offering opportunities for radiobiological experiments in...

Tissue and Cell Culture

More than 200 types of cells make up the human body. They are assembled into a variety of tissues, such as skin, bone, and muscle. Most tissues contain a mixture of cell types. Cells are small and complex, which makes it difficult for scientists to see their structures, to discover their molecular composition, and especially to find out how their various components function. What can be learned about cells depends on the available tools. Culturing (or growing) cells is one of the most basic...

Microgravity Facilities

While balloon flights cannot provide a microgravity environment directly, they can be used to expose samples to radiation similar to those encountered in orbit. They can therefore be used to provide information to complement results from orbiting experiments. While it is highly desirable to have a control 1-g centrifuge on every microgravity mission in order to separate the effects of the space environment from those of microgravity (see this Chapter, Section 2.3), this is not always possible....

Principles of Development Biology

3.1.1 The Making of a Living Organism The structure and composition of living organisms varies greatly, from single-celled bacteria to complex multi-cellular organisms with differentiated cell types and interconnected organ systems. Regardless of the complexity, every living entity contains a blueprint for its construction in the form of a double-helical chain of molecules called deoxyribonucleic acid or DNA (Figure 1-14). DNA is an amazingly simple chemical structure, yet it contains an entire...

LEO Missions

The current guidelines for radiation protection in LEO missions have been derived from a postulated acceptable risk for late cancer mortality, which had been justified by comparison with mortality rates from normal terrestrial occupations (NCRP 1989, 2000). For space missions in LEO, a lifetime excess risk for fatal cancer due to radiation exposure of 3 was judged reasonable, taking into account the fact that space crews have to cope with other serious risks besides the radiation risk. This...

References

Adams GR, Haddad F, Baldwin KM (2003) Gravity plays an important role in muscle development and the differentiation of contractile protein phenotypes. In The Neurolab Spacelab Mission Neuroscience Research in Space. JC Buckey, JL Homick (eds) NASA Johnson Space Center, Houston, NASA SP-2003-535, pp 111-122 Adams GR, McCue SA, Bodell PW, Zeng M, Baldwin KM (2000) Effects of spaceflight and thyroid deficiency on hindlimb development. I. Muscle mass and IGF-I expression. JApplPhysiol 88 894-903...

Development of the Root System

It has been shown that in the primary root the elongation zone was modified in mierogravity. For instance, in lettuce seedling roots the length of the cell elongation zone was shorter in mierogravity than in the onboard 1-g centrifuge (Merkys and Laurinavicius 1990). The presence of cells elongating closer to the quiescent center9 indicated that there was an acceleration of the cell differentiation process. For example, the formation of root hairs occurred at a shorter distance from the root...

Effects of Radiation Exposure on Humans

The quality factor has originally been developed for radiation protection purposes. Therefore it is mainly based on radiation risks for cancer induction in mammals. The effects of radiation exposure on humans can be grouped into two basic categories acute effects or delayed effects. Acute effects usually appear quite soon after exposure when people receive high 5 Figure 7-04 shows the percent contribution from the different ions of GCR to the dose equivalent. doses in a short period of time...

Germination and Root Orientation

Many species have been grown in mierogravity or on clinostats and it appeared that the absence of gravity or simulation of weightlessness had no real effect on germination (Halstead and Dutcher 1987, Kordyum 1997). However, the orientation of growth of the radicle, which is strongly dependent upon gravity on Earth, is related to the position of the embryo in mierogravity or in simulated mierogravity (Volkmann et al. 1986). Thus, as it develops on a clinostat the primary root shows spontaneous...

Results of Space Experiments

It is estimated that in about 20 of the different proteins and other biological macromolecular assemblies that have been studied in space, the resolution of the crystallographic analysis was better than that of the best ground-based results available at the time. The proteins whose resolution improved in space range from well-understood test cases, such as lysozyme, to proteins that present significant challenges for contemporary structural biology, such as the EcoRI-DNA complex, the nucleosome...

Cleavage Gastrulation and Neurulation

Since the beginning of the 20th century, authors hypothesized that gravity played a role on early embryonic development, in particular on the orientation of first cleavage, the formation of the antero-posterior axis, and the subsequent morphogenesis and organogenesis that are very often characterized by the regular patterning of morphological structures. The basic principles of embryonic development are described in Chapter 1, Section 3.1. Experiments were done with frog eggs during...

Plant Gravitropism What is Known and What is to be Done

Microgravity has represented a very useful tool to analyze gravitropism since it was the only opportunity to clearly measure parameters such as the presentation time, the presentation dose, and the threshold acceleration for the gravitropic reaction. Although clinostats have been used for a century, their action remains not clear. Clinostat works Aarrouf et al. 1999 have shown that the rotation about a horizontal axis on a clinostat could eventually produce a slight but continuous stimulation,...

Estimate of Gravisensitivity

Gravis ens itivity represents the ability to respond to a gravistimulus and can be estimated by different stimulation thresholds Volkmann and Sievers 1979 a. The minimal angle rm with respect to gravity that induces a reorientation of the extremity of the organ b. The presentation time tp , which is the minimum duration of gravistimulus at 1 g to provoke a slight but significant gravitropic response c. The threshold acceleration at that can be sensed by the plant organs. The first parameter rm...

Clinostat and Bioreactor

Shoot Clinostat

On Earth, plant scientists have conducted many experiments to try to unravel the apparently simple responses of plants to the Earth's gravity. The basic problem is how to modify the amplitude of gravity so that developmental responses under different gravitational force levels can be studied. On of the earliest experimental devices for approaching this problem was to rotate material as Knight 1806 has done, but oriented horizontally on the periphery of a disc rotating in a vertical plane see...

Gravitropic Response in Microgravity

The gravitropic response of lentil seedling roots was first analyzed during the Spacelab S MM05 mission Perbal et al. 1999 . The lentil seedlings were grown in microgravity for 26 h and then placed on the centrifuge for 22 min. The gravitropic response was followed by time-lapse photography. In microgravity, the tip of gravistimulated roots could overshoot the direction of the acceleration after 3 h Figure 6-13 , whereas roots stimulated on the ground or in space continuously did not see Figure...