title: Responses of the photosynthetic flagellate, Euglena gracilis, to microgravity.
abstract: Motility and orientation have been studied in the unicellular photosynthetic flagellate. Euglena gracilis, using real time image analysis capable of tracking up to 200 cells simultaneously before, during and after a sounding rocket (TEXUS) experiment. The cells orient negative gravitactically under 1 g conditions and the degree of orientation increases with time when kept in a closed system.  Under micro-g conditions the cells orient randomly and display no cooperativity between the individuals. Under 1 g conditions the velocity, which has been determined simultaneously to the orientation vectors, depends on the direction of swimming with respect to the gravity vector. Under micro-g conditions the cells swim significantly faster. After retrieval of the rocket the cells returned to normal gravitaxis and motility as observed before the space flight.
authors.affiliation: Institut fur Botanik und Pharmazeutische Biologie, Friedrich-Alexander-Universitat, Erlangen, West Germany.
authors.forename: D P
authors.initials: DP
authors.lastname: Hader
authors.forename: K
authors.initials: K
authors.lastname: Vogel
authors.forename: J
authors.initials: J
authors.lastname: Schafer
mesh_terms: D000818:Animals; D005056:Euglena gracilis / Q000502:physiology*; D018466:Gravity Sensing / Q000502:physiology*; D009043:Motor Activity / Q000502:physiology*; D009949:Orientation; D013026:Space Flight; D013550:Swimming; D014893:Weightlessness