Effects of some space flight factors on survivorship in crustacean resting stages V.R. Alekseev*, M.A. Levinskih**, N.D. Novikova**, V.N.Sychev**, T. Okuda***, *Zoological Institute of RAS, St. Petersburg, Russia **Institute for biomedical problems RAS, Moscow, Russia*** National Institute of Agrobiological Science, Tsukuba , Japan
In accordance with the Russian space research program, the study on cryptobiosis is important for: • Planetary and space craft quarantine • Ecosystem transportation outside The Earth Biosphere • Extraterrestrial life searching (Alekseev, Sychev, Novikova 2007)
During space flight organisms are affected by a set of factors different from Earth conditions • Microgravity • Space (corpuscular) radiation • Transformed magnetic field • Over gravity (during start) • Industrial factors (noise, vibration, electro-magnetic field) • Varies combinations of 1-5 with possible synergic effects
OBJECTIVES of this study: • to find out if Factors of Space Flight (FSF) play a negative role in vital abilities of cryptobiotic stages • if YES, what kind of effects the FSF on dormant stages can we get than and how to overcome the effects by before-flight measures
“AQUARIUM” experiment: Cryptobiotic stages were transported to ISS (Russian segment) and exposed 1-8 months INSIDE station
Resting stages of two species were selected for this experiment in space A phyllopod crustacean Streptocephalus torvicornis A cladoceran Daphnia magna
Материал: • D. magnaиS. torvicornis собирались в дафниевых прудах осетрового рыбзавода в дельте Волги • В этих прудах на протяжении 30 лет формировалась микроэкосистема из организмов способных к длительному биологическому покою.
2. “Biorisk” experiment: cryptobiotic stages were placed for 13-18 months OUTSIDE ISSS
1. Hatching of resting egg exposed inside ISS • Hatching started on the third day after moving from 10o to 25o C • The reactivation rate : in ISS 39.6 % (30.6) • In control 51,8 % (39.9) (t-test; p=0.035)
Average body mass in newborn Daphnia after ISS treatment within one month
Size and reactivation in Daphnia First Medium Post
Differences in time of reactivation among clones confirmed with PCR • F - first group • M – middle group • P – posterior group
Discriminative analyze based on 24 signs revealed that time of reactivation in 3 clones were genetically specified • F - first group • M – middle group • P – posterior group
1. 2 week NR Hatching =16.3+17.29% 2. 4 week NR Hatching =23.5+18.16% 3. Control Hatching = 35.5 +20.75% p1-3=0,1 p2-3=0.22
FSF also affected some life cycle parameters in D. magna. • The first clutch size: in ISS-treated (11+3.6 egg i -1) in control group (14.3+2.8 egg i-1) ( t-test; p=0.0477). • Maturation time: in ISS (9.95+0.284 day) in control (10.31+0.372 day) (Mann-Whitney test zadjust=2.09, p=0.033).
Males in D. magna in offspring. • In ISS offspring 54.9+25.94% males • No a single male in offspring from control group!
S. torvicornis resting eggs were used to trace increasing of negative changes with time • Resting eggs of this species were collected in the same ponds in density several times more than Daphnia ephippia
2. Nine species were selected to study effect of open space conditions • Daphnia magna (winter dormancy) • Daphnia pulicaria (summer dormancy) • Streptocephalus torvicornis • Artemia salina • Eucycpris ornata • Polypedium vanderplankii • Nothobranchius guenteri (eggs of African fish)
Daphnia magna Daphnia pulicaria Streptocephalus torvicornis Eucycpris ornata Nothobranchius guenteri Polypedium vanderplankii Artemia salina Survived Died Survived Survived Died Survived Survived Results of “Biorisk” treatments
Conclusions: • Cryptobiotic stages of aquatic invertebrates are effected by FSF inside space station but also are able to overcome them outside station • Space radiation seems like responsible for main negative effect inside station exposing • Resistance to FSF in most species studied was related with trehalose content in their bodies that can help for before-flight selection/preparation the most resistant to FSF specimens
Acknowledgments: • This study was supported by RFBR-Japan bilateral grants • VA got a fellowship from Max-Planck-Society • Drs. N. Abramson. T. Kikawada, O. Gusev and Prof. Vladimir Tzetlin are very much appreciated for significant help in experiments and productive discussion on their results THANK YOU FOR ATTENTION!