Whom Pressure wouldn't squash , Fire wouldn't burn

Tardigrade 
Courtesy:
EnWikipedia 

Spineless  and tiny  it maybe,  but  the Tardigrade has shot into fame. Readers of the Guardian have  voted it  to be  the  invertebrate  of the year 2025.    Popularly  known as water bear or moss piglet,  tardigrades are like tiny elongated pouches  less than a millimeter in length. But don't dismiss them  just because  of  their size.   They are  omnipresent and practically  indestructible.  They  can withstand  subzero temperatures  and  the  volcanic  heat , intense radiation pressures upto 600 MPa and even vaccuum.  In other words  they are extrtemophiles with mind boggling resilience.   When confronted with  such adverse  ambience they simply  withdraw into  cryptobiosis, a desiccated state in which  bodily functions are bare minimum.   They  can survive in this state  for decades.  The organism resuscitates itself  from the dormant  state, when conditions become favorable.  It presumed that it has survived through the  5  five apocalyptical  planetary extinction events.  The  earliest  which happened 440 million years ago wiped out most of the marine species due to global cooling.  The latest which occurred 66 million years ago saw to the end of non-avian dinosaurs.  So what is so special about the tardigrade? 

Anatomy of Tardigrade: Courtesy En Wikipedia

Tardigrade is a simple uncomplicated organism. Its body cavity is filled with a colorless fluid  hemolymph which   facilitates oxygen and nutrient transport. It  has eight stubby legs which it can move individually or collectively. Its nervous system too is  very elementary.  A cerebral ganglion on the head serves as the  brain from which  two nerve cords  run under the belly along the whole length of body connecting smaller local nerve centres.  Neurons may not exceed  200 in number. With such simple arrangement tardigrade can swim, walk or glide as it pleases, the speed and gait depending on the terrain on which it moves. It has a mouth for food intake and anus for waste removal. The eyespots, sensory whiskers and chemoreceptors collectively function as sensory organs.  Above all they can multiply sexually or asexually.  Enough for existence  as well as subsistence.

Scientists irrespective of the   disciplines  they work,  are   enamored  with this tiny yet resourceful organism.   For example  oncologists  have long been  frantically looking for ways and means to reduce collateral   damage to healthy tissues of patients  receiving  radiation therapy.  And here is this simpleton who can withstand  intense doses of radiation.  Research has revealed  that  tardigrades have a special protein  called Dsup (short for Damage Suppressor Protein)  in their genetic makeup.   Dsup is a  disordered polypeptide  chain of   445 amino acid residues most of which are  positively charged.  These positive charges  facilitate it  to wrap around   the negatively charged  DNA as a protective cover.   When  Dsup gene  is incorporated  into the  genome  of  laboratory mouse, the protein is expressed and  the   mouse exhibits  radiation tolerance.   

The ultimate in biomedical electronics  is nanotattooing  of biosensors and control devices on the patient's skin itself.  As of now this happens only in science fiction.   Nano lithography (or nanopatterning) as the process is called, is well standardized  for inert surfaces and  a variety of techniques are available to choose from.  However   none is  suitable for live biological tissues  because the  processes involve several harsh steps  such as   intense  radiations, wet/dry etching, high temperature  curing,  toxic solvent wash, vacuum etc.  Recently   a group of  scientists  from the School of Engineering, Westlake University, Hangshu  and Institute  for Optoelectronics, Hangshu, China. decided o take advantage of the cryptobiotic behavior of tardigrades.  The   organism  was cooled to subzero temperature, goading it to go into  cryptobiotic stage.  While in  that state, it was given a protective coat of  anisole.  A  nanodesign  was tattooed  on the ice layer formed over the anisole coat  using an electron beam.  Wherever the beam impinged,  anisole reacted to leave a biocompatible mark.  The unreacted anisole layer was then vacuum evaporated.   When  brought back to room temperature the organism displayed the nanotattoo.    

A  batch of tardigrades in the dormant state of course,  flew  to  the moon in an Israeli spaceship,  Beresheet in 2019.  Unfortunately  the spaceship  crash landed   on the lunar surface. It is presumed that the  crash as well as the unfriendly ambience of the moon would have been too much for the tardigrades  to survive.  But who knows, perhaps future holds that secret. 

Tailpiece:

Cosmo Sheldrake 's  song   If I were a tardigrade.....  ends  like this :

If I shed all my liquid and let myself dry out

I'll shrivel and sleep for some 15-odd years

I'd wake up, come water, and get on with living

With time in my pocket to pass by the day

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REFERENCES:

1.It’s heroic, hardy and less than a millimetre long: meet the 2025 invertebrate of the year

2. The biomedical potential of tardigrade proteins: A review

3. Patterning on living tardigrades: Yang et al  Nano Lett. 2025, 25, 6168−6175