GENETICALLY MODIFIED ORGANISMS: BT CORN, IS IT WORTH THE RISK?

Source: The Science Creative Quarterly

By Hardy Hall

Bt corn, a genetically modified organism (GMO), has been both the poster-child and thorn-in-the-side of the plant biotechnology industry from the late 1990’s to present. There are several versions of this transgenic crop that each have a gene from an insect pathogen, Bacillus thuringiensis (Bt), which encodes a protein toxic to the European corn borer (ECB), an insect pest that eats and destroys corn stems (see Figure 1). Bt corn has proven effective in reducing crop damage due to ECB, yet public opposition to Bt corn has escalated amid fears of human health and environmental risks associated with the production and consumption of Bt corn.

Figure 1. Engineering resistant corn. Following the insertion of a gene from the bacteria Bacillus thuringiensis, corn becomes resistant to corn borer infection. This allows farmers to use fewer insecticides

History of Bt


Bt corn draws its humble origins from France, where in 1938 B. thuringiensis bacteria was grown in large quantities and sprayed on corn crops to prevent ECB damage[1]. Artificial selection of Bt strains has led to the successful targeting of many insect pests. Because no toxic effects of Bt on humans have been detected in its seventy years of use, it is now considered an acceptable pest control measure for the organic food industry[2]. To this day, Bt is an important part of many integrated pest management strategies. The success of the Bt spray has been limited because the bacteria cannot survive for very long on the plant’s surface. Bt is particularly ineffective at controlling ECB because these insect live most of their larval life inside the corn stem, not on the surface: sprays are only effective when the insects are starting its journey into the stem. Thus, a means of penetrating corn tissue with Bt is required to offer long-term anti-feeding measures against tunneling insects such as ECB.
Mechanism of Bt toxicity


Researchers investigated how this bacteria kills particular insects and discovered that Bt has two classes of toxins; cytolysins (Cyt) and crystal delta-endotoxins (Cry)[3]. While Cyt proteins are toxic towards the insect orders Coleoptera (beetles) and Diptera (flies), Cry proteins selectively target Lepidopterans (moths and butterflies). As a toxic mechanism, Cry proteins bind to specific receptors on the membranes of mid-gut (epithelial) cells resulting in rupture of those cells[4]. If a Cry protein cannot find a specific receptor on the epithelial cell to which it can bind, then the Cry protein is not toxic. Bt strains will have different complements of Cyt and Cry proteins, thus defining their host ranges[5]. The genes encoding many Cry proteins have been identified providing biotechnologists with the genetic building blocks to create GM crops that express a particular Cry protein in corn that is toxic to a particular pest such as ECB yet potential safe for human consumption.

Making Bt corn


As it turns out, nature has its own biotechnologist called Agrobacterium tumefaciens which induces the growth of tumours on woody plants. These tumours are engineered by A.tumefaciens to produce a special food for the bacteria (opines) that plants normally cannot make. These tumours arise from a unique bacterial transformation mechanism involving the Ti-plasmid which coordinates the random insertion of a subset of its DNA (t-DNA) containing opine synthase genes into a plant chromosome[6] (see Figure 2). By replacing portions of the t-DNA sequence with genes of interest (such as Cry), researchers have been able to harness this transformational mechanism and confer new traits to many flowering plants including grasses such as corn7 and rice[8]. Cry-transformed corn varieties, called ‘Bt corn’, produce sufficient levels of Cry proteins to provide an effective measure of resistance against ECB and are now widely grown in North America.


Figure 2. General schematic of GM crop production

Human health and environmental risks


The promise of this technology has been largely overshadowed by concerns about the unintended effects of Bt corn on human health and the environment. Cry protein toxicity, allergenicity, and lateral transfer of antibiotic-resistance marker genes to the microflora of our digestive system threaten to compromise human health. Despite these alarming possibilities, the risks to human health appear small based upon what is known about the bacterial endotoxin, its specificity, and confidence in the processes of plant transformation and screening[9]. The task of determining the levels of such risks, however, are immense. Human diets are complex and variable. How can we trace the acute or chronic effects of eating GM ingredients when they are mixed in with many other foods that may also present their own health hazards? It is even more complicated to determine the indirect risk of eating meat from animals raised on transgenic crops. These tests take time, and the results of clinical trials are not always clear-cut. It will likely take decades before we can know with any certainty if Bt corn is as safe for human consumption as its non-GM alternatives[10].

We currently know very little about the actual ecological risks posed by Bt corn. Bt corn may be toxic to non-target organisms, transgenic genes may escape to related corn species, and ECB and other pests may become resistant to Cry proteins[11]. The alleged effect of Bt corn pollen on Monarch butterfly larvae has rocketed to the front pages of major newspapers around the world (ex. CNN). Some research has shown that Monarch butterfly larvae fed their normal diet of milkweed leaves suffer a significant decline in fitness when those leaves are dusted with Bt corn pollen (Losey et al. 1999). The methodology of this experiment, however, has been harshly criticized by members of the scientific community.

Most recently, the threat of Cry gene escape into wild populations has been substantiated by the discovery that artificial DNA from transgenic corn has been detected in traditional corn varieties in remote areas of Mexico (Quist and Chapela, 2001). However, this study was pulled from NATURE magazine in an unprecedented fashion following a heated scientific and political debate[12]. While few contest that such transgenes are present in the local corn races of Mexico, there is still no evidence to suggest that these genetic constructs are “escaping” to become established in local corn races. We are limited to an educated guess as to the likelihood and speed of such genetic pollution[13].

Balancing risk and benefit


Despite the lack of conclusive evidence that GM foods present considerable risk to human health and environment, widespread use of this new technology is being compared to past mistakes such as broadcast spraying of populated towns with DDT to control mosquitoes during the 1950s. Notions of “frankenfoods”[14] and “agroterrorism”[15] corrupting our planet present theoretical possibilities that cannot be discounted given the remarkable ability of the unlikely to become an actuality. In truth, we must plead ignorance of the long-term impacts of GM crops[16].

Arguably, every food in our current diet carries with it associated risks, determined through “trial-and-error” extending back before to our hunter-gatherer origins. Often, we will accept a certain degree of exposure to known hazards to receive known benefits. Bt corn has obvious benefits for agricultural production, increasing profit margins through more efficient and consistent corn production and improving the working environment for farmers through reduced exposure to pesticides. In a surplus market, these benefits may be passed on to the consumer as a grocery bill reduction. On a global scale, decreased crop losses due to herbivory may translate into improved world food supply since corn remains a major staple in the global diet. Ecosystems are not likely to benefit from ECB-resistant Bt corn propagation since this technology replaces a largely mechanical (non-chemical) control for ECB.

These benefits, real or imagined, have been used as leverage by Bt corn proponents in the argument to accept what they argue are minimal levels of health and environmental risk. Yet many consumer, civil rights, and environmental advocacy groups characterize such arguments as industry propaganda, asserting that corporate benefits should not out-weigh the undetermined human health, socioeconomic and environmental risks.

The relative ease in engineering Bt biopesticides into crops such as corn, cotton and rice, combined with the cost effectiveness of Bt crops for growers under threat of ECB, makes banning this technology in North America seem unlikely. This reality highlights the necessity for the research community to improve methods for assessing risks posed by GM crops. While some industry proponents may resist, it is ultimately the public’s responsibility to ensure that this new technology is properly managed in the context of other pest management methods that have their own set of risks and benefits.

Notes


Glossary


Artificial Selection – the encouragement of certain traits in an animal through selective breeding by humans, both intentional or unintentional
Ti plasmid – “tumour-inducing” plasmid: originally found in the bacterium Agrobacterium tumefaciens, this plasmid integrates into a host cell genome and causes galls on plants. Biotechnologists can take advantage of this integration to insert genes of their choice into plant cells.
Lateral transfer – also called horizontal gene transfer, the movement of genetic material from one organism to another other than from parent to offspring, and often across species, genus, or even domain.
Antibiotic resistance marker genes – genes that allow biotechnologists to distinguish between plants that have been modified properly and those that have not depending on their suceptibility to antibiotics.
Screening – the process of selection of desirable plants from a large population of transformants (different insertional events) with variation in trait depending on location and number of t-DNA insertions.
Herbivory – the consumption of plants by animals, in this case to the detriment of the plant (predation).

References


1. Van Frankenhuyzen, K. in Bacillus thuringiensis, An environmental biopesticide: Theory and practice (John Wiley & Sons, 1993).
2. Whalon, M.E. & Wingerd, B.A. Bt: mode of action and use. Arch Insect Biochem Physiol 54, 200-211 (2003).
3. Crickmore, N. et al. Revision of the nomenclature for the Bacillus thuringiensis pesticidal crystal proteins. Microbiol Mol Biol Rev 62, 807-813 (1998).
4. Dorsch, J.A. et al. Cry1a Toxins of Bacillus Thuringiensis Bind Specifically to a Region Adjacent to the Membrane-Proximal Extracellular Domain of Bt-R-1 in Manduca Sexta: Involvement of a Cadherin in the Entomopathogenicity of Bacillus Thuringiensis. Insect Biochemistry and Molecular Biology 32, 1025-1036 (2002).
5. De Maagd, R.A., Bravo, A. & Crickmore, N. How Bacillus Thuringiensis Has Evolved Specific Toxins to Colonize the Insect World. Trends in Genetics 17, 193-199 (2001).
6. Bevan, M.W. & Chilton, M.D. T-DNA of the Agrobacterium Ti and Ri plasmids. Annu Rev Genet 16, 357-384 (1982).
7. Ishida, Y. et al. High efficiency transformation of maize (Zea mays L.) mediated by Agrobacterium tumefaciens. Nat Biotechnol 14, 745-750 (1996).
8. High, S.M., Cohen, M.B., Shu, Q.Y. & Altosaar, I. Achieving successful deployment of Bt rice. Trends Plant Sci 9, 286-292 (2004).
9. Kuiper, H.A., Kleter, G.A., Noteborn, H.P. & Kok, E.J. Assessment of the food safety issues related to genetically modified foods. Plant J 27, 503-528 (2001).
10. Sudakin, D.L. Biopesticides. Toxicol Rev 22, 83-90 (2003).
11. Sharma, H.C. & Ortiz, R. Transgenics, Pest Management, and the Environment. Current Science 79, 421-437 (2000).
12. Ochert, A. Caught in the maize at Berkeley. California Monthly (2002).
13. Letourneau, D.K., Robinson, G.S. & Hagen, J.A. Bt crops: predicting effects of escaped transgenes on the fitness of wild plants and their herbivores. Environ Biosafety Res 2, 219-246 (2003).
14. Golden, F. Who’s afraid of Frankenfood? Time 154, 49-50 (1999).
15. van Bredow, J. et al. Agroterrorism. Agricultural infrastructure vulnerability. Ann N Y Acad Sci 894, 168-180 (1999).
16. Hoffmann-Riem, H. & Wynne, B. In risk assessment, one has to admit ignorance. Nature 416, 123 (2002).
(Art by Jiang Long and Jen Philpot)


Original source:
http://www.scq.ubc.ca/bt-corn-is-it-worth-the-risk/

EARTH´S BEES IN MONSANTO´S HANDS?

Source: maryamhenein.tumblr.com

Post date: January 25, 2012

There was quite a stir amongst beekeepers and anti-gmo activists this past October 2011 when chemical and seed giant Monsanto purchased Beeologics , a small company best known for its  “groundbreaking research” vis a vis the application of RNAi technology on honeybees, a mechanism meant to block gene expression.

This was Monsanto’s first acquisition of a pest control biotech company. Yet surprisingly the terms of the deal were not disclosed.

Since its inception in 2007, Beeologics has been developing Remebee,® an anti-viral treatment for use in honeybees affected with Israeli Acute Paralysis Virus (IAPV), a bee-specific virus, which originated from Australia and found and named in Israel in 2002.

I first heard about Beelogics, which is headquartered both in both Florida and Israel, in April 2008 when President and CEO Eyal Ben-Chanoch reached out to Vanishing of the Bees via email after viewing our trailer and spotting some familiar faces.

Eyal explained that Beeologics was assembling scientists, beekeepers and business people “to create the missing corporate support” in an industry that traditionally has only been supported by a few hardware manufacturers. Sure there were hives, tools, bee suits and the like being offered but very little had been invested in technology and medicine for the bees — until Beeologics came along that is.

To put things in context, many scientists were all abuzz about IAPV at the time. Many firmly believed that it was a primer for Colony Collapse Disorder. Remembee, meanwhile, was regarded as a first line of defense to control the virus and its effect on bee mortality.  

We inoculate humans, why not insects?

Eyal assured me that Remembee wasn’t another “snake oil” product but rather a treatment developed by ‘real’ scientists at the Hebrew University in Jerusalem. They were testing the product with the help of the University of Florida, Penn State, the USDA/ARS and some of the largest beekeepers in the country including David Hackenberg, CCD’s poster child and the main character in our film.

While CCD is a complex issue no-doubt, I told Eyal that our findings pointed to another cause: newfangled chemicals called systemic pesticides. Instead of being applied to leaves, they are enrobed on seeds and/or entrenched in the soil, allowing for the poison to literally become part of the plant.

Consequently, honeybees bring the systemics back to the hive in the form of pollen and nectar and store it in their honeycomb. When future generations dip into their reserves, they ingest toxins that target their central nervous system, affect their navigational capabilities and impair their memory. More importantly, the chemicals compromise their immune system – the number one key to fighting any kind of insult to the body, including a virus like IAPV. 

As a scientist Eyal didn’t quite agree with our conclusions.  

“While I am also concerned with the world we are going to leave to our children, those who are using so-called facts that are based on pseudo or incomplete scientific work are as dangerous as the chemical companies who don’t release the data they have,” he concluded.

Which brings us back to Monsanto, arguably the most detested chemical company on the face of the planet.

Why were they drawn to Beeologics? Was it because the competition (Syngenta and Bayer Crop Science) had also expressed interest? Or was it because they’d identified some low-hanging fruit to add to their portfolio of proprietary life forms? Perhaps Monsanto, which boasts a revenue of more than $10.5 billion per year, plans on buying anything and everything to do with gene manipulation?

Considering that the honey bee has been sequenced, how long before we bear witness to a genetically modified bee? I’ve been saying this since 2008 for the record!

… Introducing pesticide-resistant SUPER BEE Patent # 2457842149…

If seeds are any indication, Apis Melifera may also soon belong to Monsanto. Kill the bees with GM and pesticides, offer a band aid solution by creating a bee that is resistant to all the crap peddled on the market and then persuade/force beekeepers to buy Monsanto bees or else. It’s wicked genius.  

But surely Monsanto and many others would call all of this paranoid phooey.

Take one well known scientist/beekeeper’s take on the subject.  

“Honeybees aren’t an organism that anyone, who understands anything about their molecular biology, would advise as a subject for genetic modification,” he recently told colleagues on the online Bee List.  “Do you really think that Monsanto envisions that there would be any substantive return on investment on a patented bee? It would need to be propagated by instrumental insemination, so there would be a very limited market. This discussion is beginning to sound like the Twilight Zone.”

Insect inoculation may be the latest rave, but is it the best solution?

Today we know that subsequent research failed to confirm a link between CCD and IAPV and found that although IAPV can result in honey bee mortality, the symptoms are not consistent with those of bees dying from CCD.

With that said, why does Monsanto’s site claim that ”the Remebee® product line is now proving to be a viable solution to “Colony Collapse Disorder (CCD), “Israeli Acute Paralysis Virus (IAPV) infection and other diseases that threaten the world’s bee population.” 

Is this just bad advertising copy?

Opponents meanwhile wonder whether using an antiviral agent will result in any significant decline of CCD when we now know that bees around the country and across the world are constantly exposed to an array of highly toxic pesticides that are known to have serious effects not only on our virgins of toil, but a range of other pollinators.

Perhaps anti-viral remedies are the next generation of products used to combat agricultural pests and pathogens but they don’t deal with the root of our problems such as native bee extinctions & unsustainable agriculture (ie GE crops, pesticides and herbicides).  In the end we will still have a polluted environment.

Furthermore there may likely be unknown effects in gene expression, in anti-viral abilities, and in their cability to evolve inherent defenses against viruses, etc, adds Brian Dykstra, who holds a degree in both environmental policy & in progress pollination biology. He also manages Ethnobeeology’s FB page.

And yet Beeologics is confident that the acquisition comes at an ideal time and that they are in safe hands.

Shortly after the purchase, Nitzan Paldi (CTO and co-founder of Beeologics) posted a blog where he stated that Monsanto’s “leadership team and scientists are just as passionate about helping growers and agriculture as [they] are.”

“As a scientist, it’s gratifying that research we’ve been working on may have an opportunity to be tapped for much broader use in agriculture; potentially helping growers around the world meet the ever increasing demands being placed on agriculture worldwide.” 

And if you still have doubts fear not!

According to a Monsanto press release we should not be concerned, because it will be business as usual. Beelogics will continue to “promote bee health” under the new ownership. And Monsanto will simply use “the base technology from Beeologics as a part of its continuing discovery and development pipeline.” Whatever that means.  

How is using science to circumvent the laws of nature ever a positive thing? Facelifts and stem cell research aside of course.

To further reassure folks, the press release goes to describe Monsanto as “a leading global provider of technology-based solutions and agricultural products that improves farm productivity and food quality.” They even state that they are into sustainability. 

Jaw-dropping. Apparently Monsanto is experiencing delusions about its identity. Because the Monsanto most know is pretty much a ‘U.S. backed bioterrorist organization worthy of international intervention.’

In the past two decades, Monsanto’s seed monopoly has grown so powerful that they control the genetics of nearly 90% of five major commodity crops including corn, soybeans, cotton, canola and sugar beets!!

They make gobs of cash and yet sue farmers in poor countries who make less than $500 per year. In many cases farmers are forced to stop growing certain organic and conventional crops to avoid genetic contamination and potential lawsuits. Between 1997 and 2010, Monsanto admits to filing 144 lawsuits against America’s farmers, while settling another 700 out of court for undisclosed amounts. Due to these aggressive lawsuits, Monsanto has created an atmosphere of fear in rural America and driven dozens of farmers into bankruptcy.

As one person recently remarked on our FB page, “it’s a shitty business model to create something that can’t be controlled except by suing the hell out of people.”

And in India, thousands of farmers have committed suicide- by drinking insecticide no less- because they were promised harvests and income only to have crops fail and debts surmount thanks to their newly planted GM seeds. 

So you be the judge. Is Monsanto really getting into bee protection?  Or is this another example of man tampering with the bees - with seemingly a lot more money?

Remembee is currently being reviewed for potential commercial sale by the U.S. Food and Drug Administration. Another product RemebeePro, is also on its way. For more on RNA interference watch this video.

Original source:

http://maryamhenein.tumblr.com/post/16471484566/the-buzz-behind-the-monsanto-beeolgics-acquisition

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