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two-bacterium method.
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All this, using "natural biotech." Farming began using wild wheat -- a grass. Immunology first started
with unselected strams of Penicillium. We've learned much, mostly by trial and error, since then. The next
generation of biomining bacteria are already emerging. A major problem with the natural strains is the
heat they produce as they oxidize ore, which can get so high that it kills the bacteria.
To fix that, researchers did not go back to scratch in the lab. Instead, they searched deep-sea volcanic
vents, and hot springs such as those in Yellowstone National Park. They reasoned that only truly tough
bacteria could survive there, and indeed, found some which appear to do the mining job, but can take
near-boiling temperatures.
Bacteria also die from heavy metal poisoning, just like us. To make biomining bugs impervious to
mercury, arsenic and cadmium requires bioengineering, currently under way. One tries varieties of bugs
with differing tolerances, then breeds the best to amplify the trait. This can only take you so far. After
that, it may be necessary to splice DNA from one variety into that of another, forcibly wedding across
species. But the engineering occurs at the membrane level, not more basically --no nanotech needed.
This is a capsule look at how our expectations about basic processes and industries will alter long
before nanotech can come on line. What more speculative leaps can we foresee, that will show biotech's
limitations? -- and thus, nanotech's necessity.
Consider cryonics. This freezing of the recently dead, to be repaired and revived when technology
allows, is a seasoned science fictional idea, with many advocates in the present laboring to make it
happen. Neil R. Jones invented it in an sf story in the 1931 Amazing Stories, inspiring Dr. Robert Ettinger
to propose the idea eventually in detail in The Prospect of Immortality in 1964.
It has since been explored in Clifford Simak's Why Call Them Back From Heaven? (1967), Fred
Pohl's The Age of the Pussyfoot (1969), and in innumerable space flight stories (such as 2001: A Space
Odyssey) which use cryonics for long term storage of the crew. Fred Pohl became a strong advocate of
cryonics, even appearing on the Johnny Carson show to discuss it. Robert Heinlein used cryonics as part
of a time-traveling plot in The Door Into Summer. Larry Niven coined "corpsicle" to describe such
"deanimated" folk. Sterling Blake treated the field as it works today in Chiller. Cryonics is real, right now.
About fifty people now lie in liquid nitrogen baths, awaiting resurrection by means which must involve
operations below the biotechnical.
Repairing frozen brain cells which have been cross-slashed by shear stresses, in their descent to 77
degrees Absolute, then reheated --well, this is a job nothing in biology has ever dealt with. One must
deploy subcellular repair agents to fix freezing damage, and replenish losses from oxygen and nutrient
starvation. A solvent for this is tetrafluoromethane -- it stays liquid down to minus 130 degrees
Centigrade.
To further repair, one must introduce line-layers, workhorse cells to spool out threads of electrical
conductor. These tiny wires could power molecular repair agents -- smart cells, able to break up and
sort out ice crystals. Next comes clearing blood vessels, the basic housekeeping, functions which can all
be biological in origin.
Then nanotech becomes essential. The electrical power lines could feed a programmed cleanup crew.
They would stitch together gross fractures, like good servants dusting a room, clearing out the dendrite
debris and membrane leftovers that the big biological scavenger units missed.
Moving molecular furniture around at 130 degrees below freezing will take weeks, months. One has to
be sure the "molyreps" -- molecular repair engineers -- do not work too fast, or else they would heat the
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patient up all on their own, causing further shear damage.
How do they get the damaged stuff back in place, once they'd fixed it? Special units -- little
accountants, really -- would have to record where all your molecular furniture was, what kind of
condition it was in. They look over the debris, tag it with special identifying molecules, then anchor it to a
nearby cell wall. They file that information all away, like a library. As repair continues, you slowly warm
up.
These designer molecules must be hordes of microscopic fanatics, born to sniff out flaws and
meticulously patch them up. An army that lived for but one purpose, much as art experts could spend a
lifetime restoring a Renaissance painting. But the body is a far vaster canvas than all the art humanity had
ever produced, a network of complexity almost beyond comprehension.
Yet the body naturally polices itself with just such mobs of molecules, mending the scrapes and insults
the rude world inflicted. Biotech simply learns to enlist those tiny throngs. That is true, deep technology
--co-opting nature's own evolved mechanisms, guiding them to new purposes. Nanotech goes beyond
that, one order of magnitude down in size.
Not necessary to get good circulation in the cells again -- just sluggish is enough. A slow climb to about
minus a hundred degrees Centigrade. A third team goes in then, to bond enzymes to cell structures. They
read that library the second team had left, and put all furniture back into place.
So goes the Introduction to Molecular Repair For Poets lecture, disguising mere miracles with
analogies.
Months pass, fixing the hemorrhaged tissue, mending tom membranes, splicing back together the
disrupted cellular connections. Surgeons do this, using tools more than a million times smaller than a
scalpel, cutting with chemistry.
Restriction enzymes in bacteria already act like molecular scissors, slicing DNA at extremely specific
sites. Nanotech would sharpen this kind of carving, but much of the work could probably be
bioengineered, working at larger scales.
With such abilities, surgeons can add serotonin-derived neurotransmitters, from a psychopharmacology
far advanced beyond ours. They inhibit the switches in brain chemistry associated with emotional states.
A patient reviving may need therapy, cutting off the memories correlated with those emotions that would
slow recovery. Such tools imply medicine which can have vast social implications, indeed. [ Pobierz całość w formacie PDF ]