Making bacteria express green fluorescent protein - could it decrease fitness?

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Discussion Overview

The discussion revolves around the potential fitness implications of bacteria expressing green fluorescent protein (GFP). Participants explore whether the energy and resources required for GFP expression could lead to decreased fitness in bacterial populations, considering both laboratory and natural environments.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that expressing GFP may lead to slightly lower fitness in bacteria due to the energy and amino acids required for its production.
  • Others argue that the visibility conferred by fluorescence could be a disadvantage, potentially exposing bacteria to predation, although this remains speculative.
  • A participant notes that while transformed bacteria might be outcompeted by wildtypes, the primary purpose of GFP is for studying protein dynamics rather than fitness comparison.
  • One participant mentions that the degree of protein expression can significantly impact growth rates, suggesting that extreme expression could reduce growth to zero.
  • There is curiosity about the performance of genetically modified organisms like GloFish in natural settings, indicating a lack of definitive research on the viability of GFP in engineered organisms.

Areas of Agreement / Disagreement

Participants express varying opinions on the fitness effects of GFP expression, with no consensus reached. Some acknowledge potential drawbacks, while others highlight the utility of GFP in research contexts.

Contextual Notes

The discussion acknowledges the complexity of environmental factors affecting bacterial fitness and the lack of specific studies addressing the viability of GFP in natural conditions.

Simfish
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Since it obviously takes energy and extra amino acids to express the green fluorescent protein, so it's possible that bacteria expressing GFP might have slightly lower fitness (on average) than bacteria that aren't expressing GFP.

I'm sure the effect is negligible in most cases. But maybe these is some research that shows this? And are there borderline cases where this effect might not be negligible?
 
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Simfish said:
Since it obviously takes energy and extra amino acids to express the green fluorescent protein, so it's possible that bacteria expressing GFP might have slightly lower fitness (on average) than bacteria that aren't expressing GFP.

I'm sure the effect is negligible in most cases. But maybe these is some research that shows this? And are there borderline cases where this effect might not be negligible?

I think that being fluorescent might be more of a drawback than just taking more energy. Being highly visible even to primitive eyespots can't be a good thing if you're a bacterial colony. I don't believe that you'd notice a trend that you could be sure was due to metabolic stress, and not some other factor. I can't find studies for viability of GFP in engineered organisms, but that just says nobody bothered to check.

In the lab, they live, but I think it's safe to say that in the wild it's too complex to know how that would work. Maybe that gene confers some protection we don't know about?
 
Simfish said:
Since it obviously takes energy and extra amino acids to express the green fluorescent protein, so it's possible that bacteria expressing GFP might have slightly lower fitness (on average) than bacteria that aren't expressing GFP.

I'm sure the effect is negligible in most cases. But maybe these is some research that shows this? And are there borderline cases where this effect might not be negligible?

I'm sure the transformed bacteria would be outcompeted by wildtypes; I have to keep my transformed epithelial cells separated from my 'wildtypes' as well. But that's not really the point- GFP (or GFP fusion proteins) are used to study protein dynamics.

I wonder how the GloFish do- the ones that can be bought as pets?
 
It depends on how strongly the protein is expressed. It can reduce the growth rate to zero in extreme cases. If one strain outgrows another by 1%, the first population will be about 2.7X the second in 100 generations (assuming none die).
 

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