Involvement of the second messenger cAMP in gravity-signal transduction in Physarum.
The aim of the investigation was to clarify, whether cellular signal processing following graviperception involves second messenger pathways. The test object was a most gravisensitive free-living ameboid cell, the myxomycete (acellular slime mold) Physarum polycephalum. It was demonstrated that the motor response is related to acceleration-dependent changes in the levels of the cellular second messenger cyclic adenosine monophosphate (cAMP). Rotating Physarum plasmodia in the gravity field of the Earth about a horizontal axis increased their cAMP concentration. Depriving the cells for a few days of the acceleration stimulus (near weightlessness in a space experiment on STS-69) slightly lowered plasmodial cAMP levels. Thus, the results provide first indications that the acceleration-stimulus signal transduction chain of Physarum uses an ubiquitous second messenger pathway.
Block
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I
Section Biology, Institute of Aerospace Medicine, DLR (German Aerospace Research Establishment), Koln, Germany.
Rabien
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H
Ivanova
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K
D000818:Animals; D000242:Cyclic AMP / Q000502:physiology*; D018466:Gravity Sensing / Q000502:physiology*; D016839:Physarum polycephalum; D015290:Second Messenger Systems / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013026:Space Flight; D014893:Weightlessness
D000242:Cyclic AMP