Well. I had planned an entirely different post than
this one. Originally, it was going to
begin with a transition out of the past two consciousness and near-death
experience posts with a story from my own life.
Today, I sat down to find an appropriate paper to summarize the work I
found interesting when, to my horror, I found some unsavory allegations against
my person of choice. I had no idea. So, I decided to place that idea on the
backburner and instead revisit a topic that I posted about before but didn’t
offer too much information about yet: aging.
Forgive me, this post isn’t typical for me as I don’t usually summarize
articles that are rather self-explanatory, but I didn’t have time to do
in-depth research!
**
The
hydra is a small, fresh water animal. It
has the unique distinction of being the only animal on this planet Earth that
does not age. As long as the hydra
continues to reproduce asexually (meaning, it blubs off daughter hydra from itself
without ever mating), the hydra can – it seems – live forever. However, if it does choose to mate, then the
hydra will die after a short period.
So,
pause. The hydra can either choose to
live forever or age and die. It has both
capabilities. Isn’t that amazing? How is it choosing?
Proteins are the workhorses of our
cells; the when, which and where proteins are made are all dictated by our DNA
(to really over-simply, but still be truthful).
Therefore, the information that the hydra needs to either live
forever or age and die is found within its genome. While this seems extraordinary, it’s not such
a drastic deviation from how our own cells are known to differentiate. If you look at a brain cell and an intestinal
cell, you will find the same DNA.
However, the brain cell and intestinal cell will express different parts
of the DNA, thus creating a cell with different specialized properties. If our genomes are detailed maps of the entire
world, then the brain cell is very focused on building Paris while the
intestinal cell is much more involved in Australia. And so, when a hydra decides to mate, then
its protein expression profile must change in some fundamental way to switch it
from being immortal to mortal. DNA is
amazing.
The
short answer is that we have no idea how the hydra does this yet. Scientists are trying to learn what genes are
important in immortality and what genes are necessary for aging. More than that, though, they are focusing on more
global traits of long-living animals versus shorter lifespan animals and they
have found a few key pieces of data.
To
start with, long-living animals typically have great protection for
themselves. Clams can live to be 400
years old while giant tortoises can hang around for ~ 180 years! Both are free hide away inside their shells. Bowhead whales live for just over 200 years
and are so massive in size that they have few enemies.
Another
trait scientists have found is that cells from longer living animals are more
resistant to stresses, such as poisons (in the shape of cadmium and hydrogen peroxide)
and heat. These stressors should cause
cells to either die or become sick while dealing with the situations, but the
longevity of the animal correlates with cells being more able to cope. Less
die. Less become sick. It makes sense, of course, that the cells
would be so adaptable since the animal would be around a long time and, by
sheer chance, would run into many stresses.
If the cells were weak and died easily, then the animal wouldn’t live as
long. Underpinning the cell stability
data is the finding that these cells harbor more stable proteins. When subjected to heat, something that would
normally cause a protein to fall apart, the longer living species have proteins
that are more resistant to falling apart, meaning they can still do their job,
even in the face of a stressful situation.
Finally,
Nature seems to work a bit like the hydra.
Within every phylum (Kingdom, phylum, class, order, family, genus, species or Kings play chess on fine
glass surfaces), an array of animals exist that live for short or
longer periods of time. Evolution has
made it so life can be short or long depending on the external pressures.
The
research continues into how other animals age (or not) by studying many
species, including hydra. Scientists are
then trying to see if we can use that information to somehow slow aging in
humans. While the hydra is the most
interesting case of anti-aging we know about and humans share many genes with
hydra that are not found in fruitflies (a commonly studied laboratory animal), we do
have to remember that hydras are evolutionarily quite different than us and do
not live such active lifestyles. But
still … the possibilities are amazing. Maybe one day we all will live to be 116 or older!
****************************************************************************
Original Research
Paper 1: Years of work (8), Years
trying to be published (2), Journals that have rejected it (3), Current
status: Submitted. I’m working to make
some high resolution tables at the moment (in anticipation of the paper’s
acceptance, which I’m trying to pretend might actually happen one day!)
Original Research
Paper 2: Years of work (2), Months trying to be published (2), Journals
that have rejected it (0), Current status: favorable reviews, trying to do
one more experiment to appease a reviewer - SAME
Review Paper 1:
Requested by a specific journal, Current status: Accepted with favorable
reviews! I have to make a few small
changes, but otherwise it will print in January!
****************************************************************************
REFERENCES
Deweerdt, Sarah. “Looking for a master switch.” Nature
(2012) 492, pgs S10 – S11.
A big name in aging among animals, including the hydra: Steven
Austad of the Barshop Center for Longevity and Aging Studies, University of
Texas Health Science Center.
Congrats on Paper#1 being accepted! Woohoo!!
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