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Germs Taken Into Space May Come Back Deadlier
westlake writes "Sounds like the plot for a B-movie, doesn't it? Germs go into space and come back stronger and deadlier than ever. Except, it really happened. In a medical experiment, salmonella carried about the space shuttle in the fall of 2006 proved far more lethal to lab mice than their earth-bound source. 90% dead vs. 60% dead in twenty-six days, with half the mice dying at 1/3 the oral dose. Apparently 167 genes in the space-evolved strain had changed. The likely cause: In microgravity the force of fluids passing over the cells is low, similar to conditions in the gastrointestinal tract, and the cells adapted quickly to the new environment."
As some of the more accurate reports on this finding have pointed out, the changes were in the expression levels of the genes rather than in their composition, so no need to invoke the Flying Spaghetti Monster on this occasion! Gene expression is always responding to changes in environmental conditions, so it's not at all surprising that spaceflight is going to cause some measurable effects (hopefully in genes that are functionaly relevant to the observed change in phenotype).
It works the other way too. The outer-space-bacteria has lived and mutated in an environment without or with very few defensive system, to which it normally needs to adapt to handle them and manage to survive and proliferate. Thus the bacteria doesn't get a chance to keep it's knowledge in surviving when it come back to earth.
It's most likely to get pwnd by the first antibody or marcophage it encounters.
This lysteria is an exception because the microgravity environment it was evolving in was actually *closer* to the target environment (human gut) that the places where it usually lives. And then, as the first-poster pointed out, you have a bacteria that is quick to kill lab mice, but will probably suck at transmission because it has traded away its capacity to survive in normal environment.
People are usually marvelled at the incerdible diversity that is brought by evolution. But there's another possible point of view. Whenever some species specialize into something, it's actually losing functions : at least it is losing its polyvalence and ability to survive in diverse environment.
One may consider the human as the pinnacle of evolution given all what we managed to achieve. Or we may consider the humans as a profoundly degenerate species, that has lost its ability to survive in most environment. that is hugely dependent on resources it can't produce anymore but must hunt. We've become so much fragile and incapable biologically, that we had to develop some intelligence to be able to circumvent those short comings. As opposed to a bacteria that can just grow and reproduce in a much wider set of environment without needing to grow a pair of arms to be able to do it.
This pessimistic point of view may be useful sometimes to explain or predict some phenomenon :
- like mass exctinctions
- like why the plain simple cockroaches seem to be better at surviving than mighty dinosaurs
- like what will probably happen to the outer-space-mutant-bugs
- like why intelligent design proponents are wrong with their fundamental concept of "irreductible complexity". It's not complexity, it's actually very weird, funny and circonvoluted side effects of something that was initially a simplification.
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The way I read it is that salmonella that's been raised on petrie dishes for who knows how many generations is poorly adapted to life inside the GI tract, but put it up in space for a bit, under conditions that are more like the intestine than a petrie dish and the bacteria will gain back some of it's adaptation to that environment.
Not really surprising, and unlikely to apply for all microorganisms.
"Space Bugs are Deadlier!" makes a better headline though.
It's only in fiction that the results of a satellite crash or bioweapon accident or radiation produces zombies or successful mutants who look really weird but still manage to carry a mean chainsaw.
Mutation tends to be more random than not, so you are likely to get organisms that cannot actually DO anything useful (assuming making zombies is useful) or lack any particular advantage over the original species. In fact they may be sterile or weakened.
Irradiated flesh doesn't turn into the Hulk or glow or become self-intelligent. No. It just dies.
As for this particular result of super germs, this is nothing that regular evolution could not have tried. Evolution tries many paths. Not all of them succeed. The ones that don't, die off. In this case, it sounds like the germ is more effective at killing its host animal. The ideal germ wouldn't do that. Rather it would exploit its host to spread itself to other hosts.
Suppose the germ developed a version of itself that was 100% lethal and then killed its own host before the host could spread it. Well the germ dies too, doesn't it? That evolutionary path might be more efficient but it also effectively erases itself. Nature tends to prune out such extremes.
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