Bad science in the paper ‘Hematotoxicity of Bacillus thuringiensis as Spore-crystal Strains Cry1Aa, Cry1Ab, Cry1Ac or Cry2Aa in Swiss Albino Mice’

 By: Myles Power Edited by: Peter & Hannah

I have recently published an article and video sceptical of the paper 'Long-term Toxicity of a Roundup Herbicide and a Roundup-Tolerant Genetically Modified Maize'. This paper claims to have shown a link between genetically modified (GM) maize tolerant to the roundup herbicide and an increased risk of developing tumours. Even though I discussed the problems with the paper’s experiment in detail, how the paper did not show any such link but did show a link between drinking roundup herbicide and increased life expectancy in men, and listed reliable sources to back up my claims, some people were still not happy with me. Not with what I was saying, but, bizarrely, with the time of the publication.

“haha haha why don’t you analyze the newest studies myles, why don’t you analyze the studies that sparked entire nations to ban GMOs?” – anonymous commenter

Ignoring the fact that I have previously written about the paper only five days after it was published and I am not sure how this invalidates anything I have said, I decided to take up this anonymous commenter’s challenge. Luckily another anonymous commenter sent me a link to the paper ‘Hematotoxicity of Bacillus thuringiensis as Spore-crystal Strains Cry1Aa, Cry1Ab, Cry1Ac or Cry2Aa in Swiss Albino Mice‘ along with the passive aggressive comment, “I surely hope you honor to your word, myles”. Little did he know but he had sent me one of the best examples of bad science I had ever seen; and a perfect example of the laziness of anti-genetical modified organism (GMO) groups.

Bt delta endotoxin

Before I sat down to read the paper I wanted to know what various anti-GMO groups were saying about it, because it was obvious that this anonymous commenter had copied and pasted it from one of their websites. According to the anti-GMO websites, the paper shows a link between GM food and blood cell disorders including, among other things, leukaemia. They also say that even at the lowest dose tested, the toxins were observed to induce damage to bone marrow cells and cause anaemia. It is important to note here that these websites are not saying that the specific GMOs mentioned in the paper (which produce bacillus thuringiensis (Bt) delta endotoxins) is causing health problems, but that all GMOs are; something that would be wrong even if the conclusion of the paper was correct.

I have to admit I was getting very excited to read the paper’s findings and discover just how Bt delta endotoxins expressing GMOs were causing so much damage. You can imagine my surprise when I found out that not only does the paper not show any link between the Bt delta endotoxin producing GMOs and any blood cell disorders, but it does not even investigate GM food in the first place! I am not joking! This is flat out embarrassing for every anti-GMO group and person pushing this paper as the proof of the dangers of GM food. The only reason I can see for how anyone could think this paper shows a link between GM food and blood disorders is if they haven’t even bothered to read it. In all honesty, I could finish the article here but I am just getting started at how mind-numbingly stupid this is.


So if the paper does not investigate GM food, what does it investigate, I hear you ask. The paper looks into the toxicity of “Bt spore-crystals genetically modified to express individually Cry1Aa, Cry1Ab, Cry1Ac or Cry2A”, which is another way of saying that they are looking at the toxicity of the bacteria which produce the pesticide. Just to clarify, this paper is not investigating the Bt delta endotoxin producing GM food; nor the Bt delta endotoxin themselves; but the toxicity of Bt delta endotoxins producing bacteria. To understand why it is so hilarious that anti-GMO groups are pushing this research, we first need to talk about the Bt delta endotoxins.

The Bt delta endotoxins have been extensively investigated and are considered to be more selective and safer for humans and non target organisms than most conventional insecticides. This is because they target sites that are only found in a few groups of insects. The Bt delta endotoxin is a highly selective pore-forming toxin that binds to the gut epithelium of the insect, causing cell lysis by the formation of cation-selective channels. This leads to death from septicaemia, as normal gut bacteria invade the body cavity. Even though the toxin is so specific, some people seem to be under the impression that what kills one organism will kill another, but we all know this not to be true, otherwise we would not take penicillin to kill a bacterial infection, and we would have no problem feeding chocolate to our dogs. The Bt delta endotoxins are so non-toxic to mammals that when mice where fed 3,289mg/kg of one of them (CryIAb delta endotoxin) in a single dose, no adverse effects were recorded. To put that in context, that would be the equivalent of the average British man (who weights 84kg) eating 276.3g of the purified toxin and having no adverse effects.

The paper, however, is claiming that three mice of each sex fed on 27, 136, and 270 mg/kg of the Bt delta endotoxin producing bacterias were showing negative effects. It then goes on to blame the Bt delta endotoxin contained within the bacteria rather than the bacteria itself. This flat out contradicts over 100 years of research into the toxins, and is a very sloppy conclusion from what is a very poor experiment.

long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize

Just like so many other anti-GMO papers pushed by anti-GMO groups, the sample size is far too small. You cannot achieve a statistically significant set of results using only three mice of each sex for each group, especially considering the historical incidences of these blood disorders in the Swiss Albino Mice is not reported. Although the experiment had mice drinking water, there was no appropriate blank. If the paper truly wanted to investigate the Bt delta endotoxin contained within the bacteria then a blank of Bt bacteria incapable of expressing the toxin is required. If they wanted to show that the toxin produced by GM bacteria is the cause of the problem, then they should have run a blank using the wild type Bt bacteria. Either way you look at, it without the appropriate blank, the conclusion is unfounded and confusing. They also never address the fact that these negative effects could be a result from everything else that makes up the bacteria. This paper shows just as much evidence that lipids are responsible for the mice health deterioration as it does the toxin. And one last thing; if they wanted to investigate the toxicity of the Bt delta endotoxin, then they should have investigated the goddamn Bt delta endotoxin rather than the whole bacteria.

If we look past the painfully obvious and incompetent holes in the experiment and look at the data we can see just how bad this paper is. If the Bt delta endotoxin expressing bacteria did cause various blood disorders, then you would expect to see a relationship between the dose and the response, however we don’t see this in the paper. For example it reports a “U-shaped” dose response curve with high responses at both low and high levels of Cry1Ac after 24 hours. That the mice fed the low levels of Cry1Ab had the highest response, while all levels of Cry1Aa had the same response over a 24 hour period.

What Chan

At this point you probably feel as I do – embarrassed for the people who performed and wrote this paper. You are probably wondering who on earth would publish something like this. It was published in the Journal of Haematology & Thromboembolic Diseases, and don’t worry if you have never heard of it before because this paper was published in volume 1, issue 1, and by the looks of it page 1. The journal is published by OMICS Publishing Group who have come under immense criticism after publishing pseudoscientific articles, accepting research with little or no peer review and have mislead readers into thinking there was a connection between themselves and the National Institute of Health. Let’s not beat around the bush here – this journal is fake, and the “research” it contains is a joke and would have just as much scientific merit if it were written on the back of a pub toilet.

The thing that makes this whole story hilarious and shows the laziness of the anti-GMO lot is the implications if the paper was correct. For a second, let’s ignore all the problems with the experiment, the results that make no sense and the fake journal in which it is published. Let’s say that the people on the anti-GMO websites are correct and it does show a link between Bt delta endotoxins producing GM crop (even though it does not investigate GM crop) and blood disorders. Let’s say the endotoxins are responsible as the paper states and should be avoided in your diet. If this were true, then one type of GM crop would be removed from the market but most of the organic (non-GM) produce would have to be removed as well. This is because the Bt delta endotoxins are found in nature, and therefore can be used as pesticides in organic farming. According to the Organic Consumer Association, at least 57% of organic farmers in the US use it. Yep, the same websites that are telling you to not eat GM food and instead eat only organic food are promoting a paper that is telling the reader that if they do they may develop blood cell disorders including, among other things, leukaemia. THE STUPID…. IT BURRRRRRNS!!!!!!

the stupid it burns

About Myles Power (391 Articles)
My name is Myles Power, and I run the educational YouTube channel, powerm1985. I spend what little free time I have sharing my love of SCIENCE! through home experiments, visiting sites of scientific interest, and angrily ranting at pseudoscience proponents. I am also one of the founding members of the podcast 'The League of Nerds' - which I co-host with James from 'The History of Infection'.

3 Comments on Bad science in the paper ‘Hematotoxicity of Bacillus thuringiensis as Spore-crystal Strains Cry1Aa, Cry1Ab, Cry1Ac or Cry2Aa in Swiss Albino Mice’

  1. Thanks! A friend posted an anti-GMO meme about how Pringles are owned by Kellogg (a company that makes grain products and cereals, which is now, apparently, the target of anti-GMO activists… is only 42% potato and causes the red blood cells in mice to “rupture” and “pop”. She linked to that paper as support. You’re doing good work. Keep it up!

    Expose that bad science! Teach others how to do the same!


  2. Jeff Brewster // October 6, 2014 at 8:12 pm // Reply


    You make three main points that I think are valid about the Mezzomo et al. paper:
    1. The paper does not use GM food
    2. Six mice are not enough to reach any statistically significant conclusions about safety
    3. If you want to investigate the toxicity of Cry1A(x), study Cry1A(x), not Bacillus thuringiensis containing Cry1A(x)

    But rather than compare this paper to some hypothetical ideal study, it’s informative to compare it to the study that claims to show Cry1A toxin expressed in corn is safe (the EPA registration document you cite).

    Mezzomo et al. Ciba-Geigy
    Test substance Bt spores Cry1A toxin core from E. coli
    Sample size 6 – 180 10
    Dose 0. 3 – 3 mg 35 mg
    Time frame 1 – 7 days 14 days
    Survival 100% 100%
    Other effects sub-lethal haemotoxicity –
    1. Uses GM food NO NO
    2. Uses adequate sample size NO NO
    3. Uses purified Cry1A(x) NO NO

    Each of your objections to Mezzomo can also be made to the Ciba-Geigy study. However inadequate Mezzomo may be, it provides as much support for its conclusions as the Ciba-Geigy study. There is no contradiction between the two studies, and certainly no reason to accept one and reject the other. I agree with you that a lot more work needs to be done before I would accept the Mezzomo results. But I would also need to see long-term feeding studies with 1) the form of toxin expressed in corn, 2) many more samples and 3) looking at sub-lethal health effects before I would accept the EPA conclusion that consumption of Bt Corn at typical corn consumption levels (~100 g/day for 70 years) is without deleterious effect.





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