Biologically incompatable?

[Hecateus]

I have read every now and again that it expected that alien worlds will likely be biologically incompatiable. Ie critters from planet A will be unable to consume organic matter from planet A; as the very basic building blocks would be different enough to be poisonous.

How the heck do we know this?

 

[EvilDrGanymede]

As I understand it, it's not that it would be 'poisonous', it's that the amino acids would be based on 'left-handed' proteins (I think) rather than right-handed ones.

Which means that we wouldn't be able to process them at all. Toxicity is another matter, but basically in such cases we could eat the stuff but not be able to break them down (and similarly animals on such worlds would be able to eat us and not derive any benefit).

I may be wrong there, that's just how I understand it.

 

[Hecateus]

> Here < is an article on the subject of handedness of amino acids.

on the basis of the besst guess of the article, this would, I think, qualify for general incompatibility. But appart from chemically poisonous extremophile worlds, most sectors of habitable worlds would have many worlds be mutually compatible within that sector.

> Another <

 

[RainOfSteel]

Originally posted by Evil Dr Ganymede:
As I understand it, it's not that it would be 'poisonous', it's that the amino acids would be based on 'left-handed' proteins (I think) rather than right-handed ones.

Which means that we wouldn't be able to process them at all. Toxicity is another matter, but basically in such cases we could eat the stuff but not be able to break them down (and similarly animals on such worlds would be able to eat us and not derive any benefit).

I may be wrong there, that's just how I understand it.

I've seen written into more than one SF novel the idea that in the future, foodstuff manufacturers will make left-handed protein copies of natural foods. They'll taste the same to you tongue, but they'll go through your body without being digested (for energy or fat). Potentially it would be the perfect diet food.

The one that comes to mind right away is Daniel Keys Moran's "The Long Run: A Tale of the Continuing Time"

 

[EvilDrGanymede]

Sounds like that thing in Neil Gaiman/Terry Pratchett's "Good Omens', where Famine makes a fast food that makes people fat while starving them at the same time .

 

[Zutroi]

An extreme case of the 'Chirality Problem':

There is a common drug that in a 'right' orientation is a cold medicine. The 'left' version is among the more potent narcotics. I just finished running an adventure where this disparity was applied to a common stimulant used by troops on long patrols. A 'tainted' version was being sold by a group more interested in a quick credit than in the fact that they're version would rapidly turn the user into a raving psychotic - not a good thing when your market is people with FGMPs and Powered Armor!

 

[tjoneslo]

Originally posted by RainOfSteel:
I've seen written into more than one SF novel the idea that in the future, foodstuff manufacturers will make left-handed protein copies of natural foods. They'll taste the same to you tongue, but they'll go through your body without being digested (for energy or fat). Potentially it would be the perfect diet food.

The one that comes to mind right away is Daniel Keys Moran's "The Long Run: A Tale of the Continuing Time"

This isn't just science fiction anymore. And it applies to more than proteins.
Splendra is a reversed sugar. Tastes sweet, but has no calories because it is reversed.

Olestra is a chirality reversed fat. Because the fat isn't broken down in the digestive process, it has some unfortunate side effects. Reading through the problems caused by Olestra can give the evil Referee interesting ideas for inflicting on players, without having to resort to "poison".

 

[Hecateus]

nifty...

are there any other reasons besides chirality as to why some worlds would be expected to be basically incompatible to earthlife? (assuming an otherwise earthlike world.)

In some sci-fi books, like 'Destiny's Road', some elements, like potassium in that book, are missing. In, 'March to the Sea', readers discover that Vitamin C is poisonous to the local life forms...or at least the sapient ones; much of the plant life is deadly or inedible too...but many animals are edible. In 'A Hymn Before Battle' we learn that the Posleen can eat anything organic...but humans can touch anything not made of earthlife (nevermind chirality).

 

[RainOfSteel]

Originally posted by tjoneslo:

<snip>
Olestra
<snip>
unfortunate side effects
<snip>

Don't remind me.

In the future, we'll just have to permeate Olestra with nanobots that break it down after processing in the stomach. Or something.

 

[trader jim]

this could pose a problem....Coffe Juice could POISON you if grown on different worlds....gotta do some REASEARCH!!!