E155 What Have We Learned From Taking Animals Into Space?

What is the main focus of rodent research in space?

• How microgravity environments impact organ systems (ex - bone loss, genes, molecules, and cells) 

• Health and recovery, impacts of radiation, aging, reproduction, cardiovascular health, fluid balance

Introduction: What are some challenges for using animal models in space?

size, longevity, care

What is a tardigrade? Where are they found?

Microscopic animals related to arthropods, living in sea from littoral to abyssal depth, in freshwater and terrestrial habitats at all latitudes, longitudes, and altitudes

What is cryptobiosis?

Cryptobiosis: most terrestrial species are able to suspend their metabolism completely and consequently their active life at any stage of their life-cycle (active or cryptobiotic) 

• Metabolic activities are suspended due to absence of liquid water 

• Induced by desiccation, freezing, high solute concentration, and absence of oxygen

• type of hibernation

Tardigrade tolerances to extreme conditions. What extremes can tardigrades tolerate?

• Radiation tolerance 

• Long-term survival: Survive up to 9 - 20 years under atmospheric conditions 

• Temperature extremes: Survival in temperatures close to absolute 0 

• Chemical extremes: resist exposure to CO2, hydrogen sulphide, and 1-hexanol 

• Pressure extremes: resist low and high hydrostatic pressures 

• Radiation extremes: withstand x-rays and other high radiations

Tardigrades as an animal model for space biology. Why are tardigrades a good animal model?

• Have complex biological characteristics to research space induced stress 

• Do not need large hardware facilities 

• Short biological cycles 

• Constant number of cells 

• Withstand extreme conditions

After a week in space, mice start running around their habitat as if they were on running wheels back on Earth. What are some other normal habits that the mice exhibited in space?

• Locomotion similar to hindlimb unloading 

• Running around the cage like they are running on the wheel 

• Self-grooming and eating

The article that accompanies the video, describes how tardigrades survive dessication. How are tardigrades similar to other examples of osmotic stress survival that we’ve seen in this class (e.g. frozen frogs or deep sea fish)? How are tardigrades different?

• Similar: able to come back to life after being “dead;” genes that create proteins to maintain survival during desiccation to preserve their cells during desiccation (TDPs)

• Different: do not use a type of sugar, like glucose, as the anti-freezing substance;

vomit comet

simulated space travel on reduced gravity aircraft

why are tardigrades good for space research

eggs are ressitant to environmental stress (acan dehydrate and rehydrate)

• eat microbes, nematodes, other tardigrades

anyhydrobiosis

without, H2O, life

• crybiosis: freeze tolerance

• osmobiosis: osmolarity tolerance

• anoxybiosis: no O2

tardigrades in space

desicated adults spent 10 days in space with 3 groups: space vacuum, SV and UV(a,b), and SV and UV(all)

• when they were all brought back to Earth and rehydrated in a lab, barely a difference between the control and SV in proportion of vital animals

are tardigrade eggs radiation tolerant

yes, still high survival rates at high radiation

• anhydrobiotic levels were significantly higher than the hydrated ones (indicates resistance)

heat shock protein 70

HSP70

• under stress, normal proteins unravel

• HSP70 restores the denaturing protein to a normal, wound protein

impact of heat shock proteins

flexibility in stress response due to lots of protein isoforms (applies to all stages and different proteins)

1. active nomal

2. transition during dessication

3. 14 days in cryptobiosis

4. transition to rehydration

5. rehydrated, active

antioxidants

gets rid of free-radicals

• increased antioxidant activity in dessicated species

ideal animal models for space research

small, reproduce easily, easy care

• understanding of microgravity on animal-microbe interactions