September 17, 2006 | David F. Coppedge

What’s Inside a Spore?  Nanotechnology

The spores that are emitted from fungi and ferns are so tiny, the appear like dust in the wind.  Who would have ever thought such specks could exhibit nano-technological wonders like scientists have found recently:

  1. Evapo-Motors:  Scientists at U of Michigan were intrigued by how ferns turn the power of evaporation into launching pads.  The sporangia (spore ejectors) use a “microactuator” to eject the spores into the environment as they dry out.  The team was so impressed, they said “Oh, we have to build that,” and imitated the mechanism to build microchips that open and close when wetted or dried.  They think they might be able to generate electricity without batteries with this technique.
  2. Info Compactor:  Despite their minute size, spores must carry the entire genome of the species.  A Wistar Institute press release talked about that.  It’s incredible: a histone tag on the chromatin somehow signals a compaction process that reduces the already-tight fit to 5% of the original volume.  All this must be done very delicately, because spores are haploid (one strand of DNA) and much more subject to disastrous breaks.

In the second article, the researchers found that a similar compaction method works in the sperm cells of animals as diverse as fruit flies and mice.  To them, this observation is “suggesting that the mechanisms governing genome compaction are evolutionarily ancient, highly conserved in species whose lineages diverged long ago.”

Can we just ignore that stupid little evolutionary piddle for a moment, and enjoy the fascination of these observational facts?  The ejection method of spores in ferns is just one of many highly clever and diverse seed-spreading techniques in the plant kingdom, some of which also use desiccation to advantage, like the Scotchbroom, whose pods explode to send seeds as far as 50 feet.  A beautiful film Journey of Life illustrates some of these tricks of the plant trade and is well worth watching.
    In the second story, think of how delicate and accurate this process has to be.  In the quintillions of sperm and spore cells that are produced throughout the world, most of the time the process works flawlessly.  The article did not even mention that a reverse process must also take place.  Packing is one thing, but what if you can’t unpack the information just as delicately and accurately?  Undoubtedly pollen grains have this nanotechnology, too.  A human cell can contain six feet of DNA, contained in the microscopic dot of a cell.  Many plants have even larger genomes.  A seed, sperm or spore must contain not only the entire genetic code, but the nutrients and machinery to unpack it, deliver it and protect it so that the next generation of the species can continue.  Could Darwin have known such things, one wonders how different the history of science (and politics) might have been.  Now, there’s no excuse.

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