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Thread: Genetically Engineered Food

  1. #1 Genetically Engineered Food 
    Forum Professor Obviously's Avatar
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    It seems that genetically engineered food poses a great risk when not done properly. I don't know how rich corporation do these gene manipulations, but according to studies and reports etc, the results are bad. I can only speculate that there were no proper trials to examine potential risk of certain manipulations, only that they chose what seemed to work without proper research, or we simply are still ignorant to some extent in this sort of technology. I'm not sure.

    This article here is why I brought up this thread though:

    http://www.organicconsumers.org/arti...rticle_637.cfm

    To be more specific, there's a detail I don't completely understand which my curiousity must have answered.

    To quote what I'm talking about:

    Quote Originally Posted by From Above Link
    But one study on the pat gene raises all sorts of red flags. German scientist Hans-Heinrich Kaatz demonstrated that the pat gene can transfer into the DNA of gut bacteria. He found his evidence in young bees that had been fed pollen from glufosinate-tolerant canola plants. The pat gene transferred into the bacteria and yeast inside the bees' intestines. Kaatz said, "This happened rarely, but it did happen." Although no studies have looked at whether pat genes end up in human gut bacteria, the only human GM-feeding study ever conducted did show that genetic material can transfer to our gut bacteria. This study, published in 2004, confirmed that portions of the Roundup-tolerant gene in soybeans transferred to microorganisms within the human digestive tract.
    If you see in bold, you might get an idea of what I'm interested in.

    How does genetic information get transferred to the bacteria? I want to know the specifics

    Edit:
    And do feel free to talk about genetically engineered food in general as well. I don't mind.


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  3. #2  
    Forum Cosmic Wizard i_feel_tiredsleepy's Avatar
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    It depends on how the genetic manipulation of the plant was done. They can do it in a very high-tech expensive way, or they can use Agrobacterium tumefaciens, which has the ability to insert plasmids into certain types of plants. Since this is a bacterial plasmid, I imagine other bacteria in the gut could pick it up and be transformed by it as well.

    (This is just reasoning on my part and I have no research or experiments to back it up lol, I'm sure if you looked up the paper they manage, the entomologist probably proposes a possibility)

    As a student of microbiology my knowledge of plants is pretty basic.


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  4. #3  
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    Quote Originally Posted by i_feel_tiredsleepy
    It depends on how the genetic manipulation of the plant was done. They can do it in a very high-tech expensive way, or they can use Agrobacterium tumefaciens, which has the ability to insert plasmids into certain types of plants. Since this is a bacterial plasmid, I imagine other bacteria in the gut could pick it up and be transformed by it as well.

    (This is just reasoning on my part and I have no research or experiments to back it up lol, I'm sure if you looked up the paper they manage, the entomologist probably proposes a possibility)

    As a student of microbiology my knowledge of plants is pretty basic.
    I think this is it. What I don't understand is how the bacteria pics up this plasmid. I thought that the plasmid became a part of the plants DNA. Maybe I'm misunderstanding something here. Isn't genes supposed to be a universal thing? How does the bacteria recognize and copy/take/pick up these genes which are now a part of the plants DNA? :?
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  5. #4  
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    Quote Originally Posted by Obviously
    I think this is it. What I don't understand is how the bacteria pics up this plasmid. I thought that the plasmid became a part of the plants DNA. Maybe I'm misunderstanding something here. Isn't genes supposed to be a universal thing? How does the bacteria recognize and copy/take/pick up these genes which are now a part of the plants DNA? :?
    The only way a new gene would actually get incorporated into an organism's DNA is through retroviral insertion. Most transgenic techniques involve inserting a new gene into a plasmid, which is a single circle of DNA, and then inserting that plasmid into the nucleus of an embryo (for animals) or a protoplast (for plants), so that all the resulting organism's cells contain that plasmid. But it is not incorporated into the organism's actual DNA. It's still in that separate little ring.

    Plasmids are originally from bacteria - that is how their genomes are constructed, in a circle of DNA. Bacteria also have the ability to take up pieces of genetic material, including other plasmids, from their environment. So, if you eat a piece of food whose cells' nuclei all contain this transgenic plasmid, and the cells are broken down in your stomach, releasing the plasmid, and if the plasmid or at least a piece of it containing the gene survives intact to your intestines, then the bacteria there may pick it up.
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    Plasmids are originally from bacteria - that is how their genomes are constructed, in a circle of DNA. Bacteria also have the ability to take up pieces of genetic material, including other plasmids, from their environment. So, if you eat a piece of food whose cells' nuclei all contain this transgenic plasmid, and the cells are broken down in your stomach, releasing the plasmid, and if the plasmid or at least a piece of it containing the gene survives intact to your intestines, then the bacteria there may pick it up.
    Could this aid an animal with the digestion of a new food source you think? Maybe intestinal bacteria have evolved to be able to accept and incorporate plasmids more readily, both aiding their and the host's survival in the event of the forced (or experimental) addition of new food sources to an animal's diet? Intestinal bacteria gets transferred from the animals parents in most cases, maybe further helping the addition of new food sources along by providing a mechanism for a fairly unencumbered evolutionary train? Sorry if this is deemed off-topic
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    Quote Originally Posted by KALSTER
    Plasmids are originally from bacteria - that is how their genomes are constructed, in a circle of DNA. Bacteria also have the ability to take up pieces of genetic material, including other plasmids, from their environment. So, if you eat a piece of food whose cells' nuclei all contain this transgenic plasmid, and the cells are broken down in your stomach, releasing the plasmid, and if the plasmid or at least a piece of it containing the gene survives intact to your intestines, then the bacteria there may pick it up.
    Could this aid an animal with the digestion of a new food source you think? Maybe intestinal bacteria have evolved to be able to accept and incorporate plasmids more readily, both aiding their and the host's survival in the event of the forced (or experimental) addition of new food sources to an animal's diet? Intestinal bacteria gets transferred from the animals parents in most cases, maybe further helping the addition of new food sources along by providing a mechanism for a fairly unencumbered evolutionary train? Sorry if this is deemed off-topic
    Interesting idea!
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    Quote Originally Posted by KALSTER
    Could this aid an animal with the digestion of a new food source you think? Maybe intestinal bacteria have evolved to be able to accept and incorporate plasmids more readily, both aiding their and the host's survival in the event of the forced (or experimental) addition of new food sources to an animal's diet? Intestinal bacteria gets transferred from the animals parents in most cases, maybe further helping the addition of new food sources along by providing a mechanism for a fairly unencumbered evolutionary train? Sorry if this is deemed off-topic
    Most if not all bacteria, not just gut bacteria, have this ability, so I'm fairly certain it greatly predates the symbiotic incorporation of bacteria into the guts of animals. But in general, it most likely originally evolved for a similar purpose to the one you describe, to increase variation in their genome so that they have a greater potential to adapt to changes in their environment.

    In the lab where I work I have induced E. coli bacteria to take up a plasmid. We usually do this by mixing the plasmid in a tube with the bacteria in it, and then heat-shocking the tube. This simulates a sudden, potentially dangerous change in environmental conditions, and reliably causes the bacteria to search for genetic fragments outside of themselves. Heat shocking isn't always necessary but it is one of the most common methods.
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    Sorry for the late response.

    Let's see if I got it now...

    The plasmid is inserted to a protoplast and stays there with the organisms DNA, separate. With just inserting the plasmid into a nucleus, it automatically has a function?

    It actually makes a little sense. The plasmid is recognized to be normal genetic information inside the nucleus then?
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  10. #9  
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    Quote Originally Posted by Obviously
    The plasmid is inserted to a protoplast and stays there with the organisms DNA, separate. With just inserting the plasmid into a nucleus, it automatically has a function?

    It actually makes a little sense. The plasmid is recognized to be normal genetic information inside the nucleus then?
    Of course. The designers of the plasmid make sure to include all the necessary promoter sequences with the transgene, so that the molecules in the nucleus that direct gene expression can recognize and work with that transgene.

    For example, the TRE promoter is a common mammalian expression sequence - stick that in front of a gene, and stick the combination in any mammalian cells, and the gene will be expressed. At the very least, mRNA will definitely be transcribed. Stick the combination in fish cells, and it will be largely ignored.
    Man can will nothing unless he has first understood that he must count on no one but himself; that he is alone, abandoned on earth in the midst of his infinite responsibilities, without help, with no other aim than the one he sets himself, with no other destiny than the one he forges for himself on this earth.
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    Well the Agrobacterium tumefaciens plasmid is a very interesting bacteria. It is the only bacteria I know of that inserts plasmids into eukaryotes. Most Agrobacterium species are in symbiotic relationships with plants, but tumefaciens is capably of inserting the Ti plasmid which carries a plant recognized promoter sequence and in it's natural form the plasmid encodes oncogenes that produce a tumor on the plant, and it also encodes for the formation of a glycoprotein only Agrobacterium tumefaciens can utilize. So, it forces the host plant to funnel carbohydrates to it, and it promotes the proliferation of the infected cells. It's very interesting.

    In GMO's the pathological nature of the plasmid is removed, and it is inserted into an embryonic stem cell. The plant promoter, and origin of replication remain so the plasmid is propogated in the plant. Now, what I find interesting is why wouldn't these plasmids have the bacterial promoters and origins of replication removed so that they no longer work in bacteria.

    Edit: After some digging, The Royal Commision on Genetic Modification (sponsored by the British Government) found this.

    "Various submitters described a case of apparent horizontal gene transfer of a herbicide resistance gene into the intestinal microflora of honeybees. The Pacific Institute of Resource Management [IP84] said:

    The German Television station ZDF reported on Sunday May 21, 2000 that a German researcher found a gene transfer from genetically engineered rapeseed to bacteria and fungi in the gut of honeybees. Professor Hans-Heinrich Kaatz from the Institut für Bienenkunde (Institute for Bee Research) at the University of Jena experimented during the last three years with honeybees on an experimental field with transgenic rapeseed in Saxony, Germany.

    The rapeseed was engineered to resist the herbicide glufosinate. Professor Kaatz built nets in the field with the transgenic rapeseed and let the bees fly freely within the net. At the beehives, he installed pollen traps in order to sample the pollen loads from the bees’ hind legs as they entered the hive. This pollen was fed to young honeybees in the laboratory. Professor Kaatz then took the intestine out of the young bees and spread the contents on growth medium to grow the microorganisms. He probed the microorganisms for the pat-gene, the gene that confers resistance to glufosinate. In some bacteria and also in a yeast he found the pat-gene. This indicates that the gene from the genetically engineered rapeseed was transferred in the bee’s gut to the microbes.

    Dr Beatrix Tappeser described this result as a “clear indication of horizontal transfer which has been, and is still, characterised as highly improbable”. This case became a rallying point around which the discussions of horizontal gene transfer flowed. However Professor Klaus Ammann suggested that the results described were far from conclusive. Professor Ammann stated that he knew Professor Kaatz’s work well and was “one of the committee members to revise his projects”. He told the Commission that the research was a long way from being completed and had never been published in a scientific peer-reviewed journal, although Dr Tappeser stated, “Professor Kaatz had submitted his research to the science journal, Nature, but they had refused to accept it”. Professor Ammann also considered that there was “no proof that this ... gene is not coming from normal sources”. Under cross-examination from Greenpeace [IP82], Professor Ammann denied that horizontal gene transfer had ever been shown to be a significant risk:

    There have been at least 100 experiments conducted to prove that there is horizontal gene transfer from a higher organism like [a] flowering plant to bacteria, and it has not been proven. And, I must say I am appalled by Greenpeace Europe who, on the basis of two lines in an announcement of the German TV channel, just made a big story out of it. I think that’s not the way we should proceed ... I can understand concerns, but I cannot understand blowing up a case which has not been scientifically proven. ... I think everybody in this room should be concerned about horizontal gene transfer, but it just simply doesn’t occur, you know. And, in many cases, where it would be really interesting to know it occurs, there have been done lots of experiments and nothing has been proven, nothing. The scientific world awaits the publication of the final results of Professor Kaatz’s research with interest. Until then, this remains an unproven case of horizontal gene transfer between a plant and intestinal microorganisms."

    It seems that this may not actually occur, there could be some potential here, but the research is as yet unfinished.
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    So a bacteria can, in rare cases, pick up a gene from a plasmid which it doesn't recognize? Can this be due to selection pressure (and something else?) or have I misunderstood something here?
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    Leaving aside the nutritional issue, genetically modified plants
    should NOT be allowed to breed in the wild!
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    Quote Originally Posted by Heliopolis
    Leaving aside the nutritional issue, genetically modified plants
    should NOT be allowed to breed in the wild!
    I agree, however it should be allowed to make GM plants in a controlled enviroment. I guess it depends though. If a plant is to be genetically modified, it should be done properly without any unecessary risks.
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    Quote Originally Posted by Heliopolis
    genetically modified plants should NOT be allowed to breed in the wild!
    Reads like a protester's placard.

    Why not?

    Are we actually playing with fire or is this a matter of principle, or what? I'm not opposed to diversity and real competition (i.e. some extinctions as new species kick butt). If GM plants accomplish that... why not?
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    Hmm oddly enough a lot of protesters are opposed to limiting the breeding of GMOs because it means that poorer farmers can't produce their own seeds.
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    Quote Originally Posted by Pong
    Are we actually playing with fire...
    I suppose that depends on the magnitude of the change done to the plants genome. If it's allowed to spread in the wild it could be harmful to an ecosystem (also depending upon the role the GM plant might have).
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    Quote Originally Posted by Obviously
    If it's allowed to spread in the wild it could be harmful to an ecosystem
    My (Pacific Northwest) ecosystem's experience with non-native plants (e.g. European) has generally been positive or indifferent. We've introduced a wide range of species over the last few centuries and all that caused was richer diversity. It has stressed some already precarious species, but overall this haphazard experiment has proven good.

    Letting loose some GM onions or whatever seems a minor threat compared to letting loose all current varieties in the first place. We've even hit the system with wildly different animal species. Except for certain unchecked parasites this hasn't been a problem.

    EDIT: What is "harm"? Is change harm?
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    Quote Originally Posted by Pong
    My (Pacific Northwest) ecosystem's experience with non-native plants (e.g. European) has generally been positive or indifferent. We've introduced a wide range of species over the last few centuries and all that caused was richer diversity. It has stressed some already precarious species, but overall this haphazard experiment has proven good.

    Letting loose some GM onions or whatever seems a minor threat compared to letting loose all current varieties in the first place. We've even hit the system with wildly different animal species. Except for certain unchecked parasites this hasn't been a problem.
    Interesting, I didn't think about that. So it seems that change in nature and change that we do could basically be the same thing and therefore matters little.

    Quote Originally Posted by Pong
    EDIT: What is "harm"? Is change harm?
    lol, no. Well, it depends. Obviously I meant the potential risk of putting an ecosystem of balance with killing certain key species etc. :-D
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    Quote Originally Posted by Obviously
    Quote Originally Posted by Heliopolis
    Leaving aside the nutritional issue, genetically modified plants
    should NOT be allowed to breed in the wild!
    I agree, however it should be allowed to make GM plants in a controlled enviroment. I guess it depends though. If a plant is to be genetically modified, it should be done properly without any unecessary risks.
    Actually, this ties in with my own research into statistical genetics.

    If you introduce a variant gene into a population that has selective
    advantage you will inevitably incur a "hitchhiking" effect as it
    increaes in frequency due to genetic linkage. This has been observed
    by the biotech industry.

    If the genes that hitchhike are deleterious then this can defeat the
    purpose of the introducing the superior variety in the first place.
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    Quote Originally Posted by Obviously
    Quote Originally Posted by Pong
    EDIT: What is "harm"? Is change harm?
    lol, no. Well, it depends. Obviously I meant the potential risk of putting an ecosystem of balance with killing certain key species etc. :-D
    That's about where I stand. But stopping there is relatively radical in today's preservationist groupthink. It seems the consensus is that we should even work to restore systems to earlier ideal states, as though nature is a diorama under glass.

    I think we all agree that more species, more biomass, just more stuff going on, is good. Humans have caused extinctions in the past, and our agriculture literally ploughs diversity into the ground. Yet we've also enhanced diversity in some corners of the globe by transporting species. My sense is that, apart from lands we've broken for cultivation, our thoughtless messing around has done more good on balance.

    Letting a GE species naturalize, if it will, is no more ominous than what we've done for thousands of years.
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    There is the downside that more exposure to plants engineered to be pest resistance will speed up the evolution of insects capable to get around the resistance though. An entomologist at McGill once told me that even though they use non-GM refuges in fields to keep a source of susceptibility genes in the pest populations this didn't work with chemical pesticides and it doesn't seem to be working with GM plants either. Although, this was from a prof who researches using parasitic worms as biological pesticides, so he has an interest in discrediting GM solutions to pest insects .
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  23. #22  
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    Quote Originally Posted by i_feel_tiredsleepy
    plants engineered to be pest resistance will speed up the evolution of insects capable to get around the resistance
    Naturally. So we just keep adapting one step ahead.
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  24. #23  
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    Quote Originally Posted by Pong
    Quote Originally Posted by i_feel_tiredsleepy
    plants engineered to be pest resistance will speed up the evolution of insects capable to get around the resistance
    Naturally. So we just keep adapting one step ahead.
    Haha, have to be pretty optomistic if you think we can keep that up forever, most of the chemical pesticides are already ineffective at levels non-toxic to humans.
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    I'd actually envisioned kale encrusted with thorns and bitter resins, as a logical extension of this course. Armored potatoes and such.

    Of course we can keep that up. Life's been doing this all along.
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  26. #25  
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    So in conclusion it may seem that creating GMOs and growing them in nature doesn't cause any disaster. If anything at all, it may ruin things for us
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    It's the same old fight. We can win more battles but we can't end this war. With genetically engineered crops and "smart" sprays we move more quickly now, is all.

    I don't know if that's optimistic or pessimistic. It's good enough and nothing Earth shattering IMO.
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