Bt in the Bloodstream!

Over at my favorite blog (besides this one of course!) Garden Rant, Amy Stewart posted about exploding watermelons — which Linda blogged about below — and about how Bt from genetically engineered food had found its way into our blood stream (and the bloodstream of unborn children).  Sounds pretty scary doesn’t it?  I’m not going to tell you it isn’t a little troubling, because it is, and I absolutely do not think this finding should be disregarded.  But the truth is that I’m not too worried about Bt in the bloodstream for the following reasons:

1.  The world’s ending on Saturday anyway, right?

2.  It’s impossible to tell from this study where the Bt toxin came from — I do think it probably came from transformed crops — HOWEVER, as scientists we can’t make that assumption.  We eat Bt all the time EVEN IF WE EAT NO TRANSGENIC CROPS because this bacteria is found all over the place.  I would have liked to have seen testing between people who eat transgenic food and people who eat no transgenic food.

3.  The Bt toxin is extremely specific in terms of what it affects in an insects gut.  It’s unlikely (but not impossible) that it would react with anything in our bloodstream (or an unborn child’s bloodstream).

4.  There are arguments over whether transgenic crops are sprayed more or less than than non-transgenic crops — but for insect control transgenic crops are generally sprayed less — and non-transgenic crops are sprayed with some seriously nasty stuff including nerve toxins.  If I get to pick my poison I’ll go with Bt any day.

5.  As a rule you should NEVER worry until a second study confirms the findings.  This paper is important enough that you can be sure that within a year someone else will try something similar.  If the findings hold my concerns will increase somewhat.

6.  Finally, the dose makes the poison.  Bt has been fed to various mammals for years to determine the effects that it has on them — and it generally has little effect, even over long periods of time.  These animals, obviously, had the toxin in their blood (just because it wasn’t tested doesn’t mean it wasn’t there).

It should be no surprise that when we eat something with a toxin in it, that toxin gets into our blood.  When you eat garlic — toxins from the garlic get into your blood.  When you eat hot peppers — capsaicin (an insecticide) gets in your blood.  When you drink alcohol — you get the picture.  Is it bad for things to be in the blood?  It depends entirely upon the thing and the concentration.  This article talked about fetal issues so lets use a fetal example — Aspirin is considered a bad idea during pregnancy — it can get into the unborn child’s bloodstream.  However, low doses of aspirin can reduce risks of pre-eclampsia.  By the way, a chemical very similar to aspirin is also known as a fungicide….(actigard).

So, there are my reasons for not being too worried.  Could I change my mind — YES.  Could I be wrong — YES.  BUT as a scientist who reads a lot of what I’ll call “reactionary/radical articles” I have my doubts when I read about the next thing that’s going to kill us all.  If we responded to every troubling article we’d never leave our houses.  BUT there’s always that one important article that warns us about something real — and we need to be on the lookout for it.  My reaction to the Bt threat — this isn’t it — but time will tell whether I’m right or wrong.

A word about GMOs from our visiting GP

I gave a talk to a group of gardeners last year about vegetable and community gardening.  There was a wide variety of gardening experience represented, but one statement from a seasoned gardener bothered me a bit.  And I think my response bothered him a bit too.  I haven’t thought much about it until recently, when a high school English teacher I know told me a student expressed similar ideas in her class.  The erroneous idea from my audience member was this: our tomatoes are being poisoned with ‘germetically modinified’…something something.  The arguments have lost me beyond that (because there aren’t any).  And really, there hasn’t been much talk about sex on this blog recently, so that should be remedied too.  Therefore, I would like to take the platform offered by the Garden Professors to talk about plant breeding.

 

 

Fig. 1: Jaune flammee, which has at least one gene from at least one of its parents that causes the fruit to have very little lycopene.

Conventional” breeding is when a plant breeder selects parents and offspring and tests them for desirable characteristics (traits).  It works the same way as breeding works in nature, except that we humans have a goal we’re working toward.  Firm, 5-oz, disease-resistant, crack-resistant tomatoes, for example.  In nature, the offspring that survive and reproduce the best in a given environment are ‘blindly’ selected and tend to stick around (Darwin, 1859).  Male (sperm) cells are transferred to female (egg) cells by a plant breeder, or a bee, or the wind, or a beetle, or a fly or bird or bat or moth (etc.).  The sperm and egg fuse to form an embryo, which grows to become what we’d call a plant.  In both natural and artificial selection of tomatoes, no non-tomato DNA has been added, and no tomato DNA has been removed.  By the classical definition of ‘genetic modification’, there has been none.  I suppose this paragraph was only incidentally about sex, and probably a disappointment to some.  Sorry.

Fig. 2.  Tainan, a tiny heirloom

The confusion of the issue may lie with the Flavr Savr tomato.  This was developed (yes, genetically modified) in the mid-90’s to resist softening during ripening.  It has a couple bits of manufactured DNA in it to make this possible.  The Flavr Savr is no longer grown or sold in the marketplace (that was SO 1990’s), and to my knowledge, no other transgenic tomatoes are either.

 

Fig. 3.  Rutgers, historically much-cultivated and like all other tomatoes we can buy, bred conventionally.

Confusion may also lie with the plant hormone ethylene.  Ethylene is made from incomplete combustion of fossil fuels, but it’s also made by plants.  Keep your bananas away from your carnations, right?  Bananas make ethylene gas, which causes carnations and snapdragons to senesce (die).  Tomatoes make ethylene as they ripen.  If you harvest tomatoes a bit early, but not too early, they are hard enough to ship but will still turn red later.  If you expose these pre-ripened tomatoes to ethylene gas, they will ripen more quickly and uniformly.  That’s what happens to a lot of the tomatoes in our stores.  They are not genetically modified, they are treated with a plant hormone.  That’s not unusual at all.  Ethylene is used to ripen bananas, and to help make cucumber seeds (by eliminating male flowers from female parents).  It’s used in growing ornamental plants quite a bit too (but not as much as many other hormones, and especially hormone inhibitors).

So please, if you are someone who tells anybody who will listen that the tomatoes in the store are GMOs, stop it.  They’re not.

Genetic Engineering, Veal, and Rennin

Today I thought I’d go just a little off topic. Lots of people out there are really upset about the idea of putting genes into plants, like putting genes for Round-Up resistance into soybeans, or genes for caterpillar resistance into corn. And, I do agree, this is a pretty powerful technology that needs to be used carefully – probably more carefully than it’s being used right now with plants.

But the funny thing is, one of the places where transgenic creatures really dominate the market is in a place that is almost never considered. Today 80-90% of cheese made in the United States is produced using bacteria genetically engineered to produce rennin. What is rennin you ask? Renin is the stuff normally found in a cow’s stomach which causes milk to curdle – and cheese to be created. For those of you interested in looking into this further look up rennet which is the substance in a cow’s stomach which naturally contains rennin.

After looking around a bit I really can’t find that many people upset about the use of genetically engineered microbes to produce rennin.  Actually, some people who are quite sensitive to environmental concerns may prefer it.  Historically rennin comes from dead young cows – it’s a byproduct of veal production (kind of a nasty industry if you ask me).  Rennin that comes from genetically altered bacteria has nothing to do with dead cows and so vegetarians often find cheese produced with genetically engineered rennin to be more appropriate.

Is This Really a Good Idea?

Transgenic plants have been with us for well over a decade now.  I have had the opportunity to work with many of the tools used for this technology, though most of that is far behind me (over 15 years now since I “ran a gel”) — I’m much happier being outside or even in front of a computer writing than in a lab.  Fortunately I have a number of “lab rat” colleagues so I’m relatively up to date on what’s going on and what “gene-jumper” scientists can and can’t do.

To make a long story short, over these years transgenic plants have proven to be useful in some cases (by reducing the use of certain dangerous pesticides), and concerning in others (because some genes have escaped cultivation).  I’m not going to go into the crazy ins and outs of the benefits and drawbacks of genetic engineering here except to give you my general opinion which is that every case needs to be handled individually.  I do not believe that this engineering is, in and of itself, a bad thing.  That said, I do believe that genetic engineering could get us into trouble if we’re not careful.So, with that little disclaimer I thought I’d mention something that I question — I’m not going to call it bad — but maybe it is.  There’s an “artist” at the University of Minnesota — Eduardo Kac, who had some of his genetic material placed into a petunia so that some of the proteins from his body were expressed along with the petunias.  I don’t have a picture of the petunia itself, but here on the St. Paul campus of the University of Minnesota you can see this structure, created by Kac, which is a graphic representation of a protein from the petunia.

(It was around 20 degrees outside when I took this shot — positively balmy compared to what it’s been like).

Anyway — as I said above — Though I have some concerns, I’m not opposed to using biotechnology for the “good of man.”  Nor am I afraid that Kac’s creation is dangerous — from what I know it was kept in a closed system and the petunia was ultimately destroyed — not that it would have been particularly dangerous even if it had been released.  But….to me anyway….This seems like a frivolous use of a powerful tool (that tool being the ability to move genes from one organism to another).  I don’t know if I’d call it bad….but the words Wasteful and Inappropriate come to mind.

By the way, though I know less about it, it seems that Kac also transferred genes into a rabbit for the sake of art.  But this is, after all, a horticulture blog so I thought I’d stick with plants!