Morphometric investigations of sensory vestibular structures in tadpoles (Xenopus laevis) after a spaceflight: implications for microgravity-induced alterations of the vestibuloocular reflex

Reproduction and the Early Development of Vertebrates in Space: Problems, Results, Opportunities

Humans and animals adapt to space flight conditions. However, the adaptive changes of fully formed organisms differ radically from the responses of vertebrate embryos, foetuses, and larvae to space flight. Development is associated with active cell proliferation and the formation of organs and systems. The instability of these processes is well known. Over 20 years has passed since the last systematic experiments on vertebrate reproduction and development in space flight. At the same time, programs are being prepared for the exploration of Mars and the Moon, which justifies further investigations into space flight's impact on vertebrate development. This review focuses on various aspects of reproduction and early development of vertebrates in space flights. The results of various experiments on fishes, amphibians, reptiles, birds and mammals are described. The experiments in which our team took part and ontogeny of the vertebrate nervous and special sensory systems are considered in more detail. Possible causes of morphological changes are also discussed. Research on evolutionarily and taxonomically different models can advance the understanding of reproduction in microgravity. Reptiles, in particular, geckos, due to their special features, can be a promising object of space developmental biology.

Gravitational biology within the German Space Program: goals, achievements, and perspectives

Gravity plays an important role for the evolution, orientation and development of organisms. Most of us, however, tend to overlook its importance because--due to its constant presence from the beginning of evolution some 4 billion years ago--this environmental parameter is almost hardwired into our interpretation of reality. This negligence of gravity is the more surprising as we all have our strong fights with this factor, especially during the very early and again during the late phases of our lives. On the other hand, scientists have been fascinated to observe the effects of gravity especially on plants and microorganisms for more than a hundred years, since Darwin and Sachs demonstrated the role of the root cap for downward growing plants. Different experimental approaches are nowadays available in order to change the influence of gravity and to study the corresponding influences on the physiology of biological systems. With the advent of spaceflight, a long-term nearly nullification of gravity is possible. Utilisation of this so-called "microgravity" condition for research in life sciences thus became an important asset in the space programs of various space agencies around the world. The German Space Life Sciences Program is managed--like all other space programs and activities in Germany--by the German Aerospace Center (DLR) in its role as space agency for Germany. Within the current space program, approved by the German government in May 2001, the overall goal for its life sciences part was defined as to gain scientific knowledge and to disclose new application potential by research under space conditions, especially by utilising the microgravity environment of the International Space Station. Three main scientific fields have been identified in collaboration with the scientific community: integrative human physiology, biotechnological applications of the microgravity environment, and fundamental biology of gravity and radiation responses (i.e., gravitational and radiation biology). In the present contribution, specific goals as well as achievements and perspectives of research in gravitational biology are given. In addition, some information is provided on spaceflight opportunities available.