In a message dated 2/13/01 7:36:06 PM, [log in to unmask] writes: << Jim Diamond, MD, posted the following to the Sierra Club Biotech Forum listserv on Feb. 8.--Tom Mathews --------------------------------- In answer to my post yesterday about Klebsiella planticola, Robert Mann (in New Zealand) has sent the following. He says "I compiled this piece on the Klebsiella experiment in full consultation with Dr Ingham, to give to our Royal Commission. I am not aware of any disputes about this account." I think this is the version to print out and share with your friends. ------------------------------------------------------------------------------ ------------------------------------------- Klebsiella planticola, a common soil bacterium, was genetically engineered by a German research institute to make ethanol for industrial purposes. The inventors had planned a recycling system: farmers would give them agricultural slash, which would be used for the bacterial fermentation; the resulting ethanol would be separated out, and the sludge could be given back to the farmers to spread on their fields as fertilizer. It all sounded very good for the environment, but how much soil ecology impinged on the planning is unclear. Dr Elaine Ingham of Oregon State University and her graduate student M.T. Holmes discovered to their alarm that soils containing the engineered organism killed wheat seedlings, most likely through alcohol production in the root system, which kills roots at very low concentrations. Mycorrhizal fungi were also killed. Had the engineered sludges been returned to farmers, it would have drastically degraded their soil, rendering them unable to grow many or all plants. Since K. planticola is a ubiquitous organism, found in the root systems of plants all over the world, the GM mutant could have spread and made ALL soil unable to support crops! Microorganisms are easily spread on surfaces of insects, on the feet of birds, on people's feet, etc; this engineered bacterium could have spread world-wide quite rapidly. Luckily Dr. Ingham and her student did the work before commercialization and were able to warn the company, who didn't commercialize it. The references are: Holmes T M. and E.R. Ingham (1999) Ecological effects of genetically engineered Klebsiella planticola released into agricultural soil with varying clay content. Appl. Soil Ecol. 3 394-399; Holmes T.M. and Ingham E.R. The effects of genetically engineered microorganisms on soil foodwebs. in: Supplement to Bulletin of Ecological Soc. Of America 75/2, Abs of the 79th Annual ESA Meeting: Science and Public Policy?, Knoxville, TN, 7-11 August, 1994. The story really shows the awesome power of genetic engineering, the multidisciplinary nature of the review it requires, and the folly of releasing GM microbes before very extensive contained studies. This is a very good example of how slight changes in a highly evolved bacterium can greatly change its ecological significance. Klebsiella spp have adapted to many different niches; some are also not-too-virulent human pathogens. Klebsiella pneumoniae rarely causes human disease but is a common cause of aspiration pneumonia in alcoholics (i.e. a leading cause of a somewhat rare condition). We know that small changes in bacteria or viruses often tip the delicate balance between a pathogen and host and result in large-scale outbreaks of disease. Many "new" diseases have occurred, like syphilis in the 15th century, when slightly changed microbes suddenly cause epidemics. The 1919-20 influenza pandemic, which killed about 20 million - more than the Great War it closely followed - was caused by a simple mutation in a virus. >> Although I don't recommend performing them (except in highly contained environments if at all), two experiments (or theoretical outcomes) came to mind as I read of this narrow escape from big trouble. (1) If the engineered organism killed all of the plants and microorganisms on which it fed, how would it survive? Would some precarious balance develop, between killing its food and leaving some of it alive? (I'll not speculate on what would happen to the rest of us, in the meantime, if this were a global experiment.) Perhaps what I'm getting at, is, "Is this engineered microorganism well adapted to survive in the competitive natural world? What sort of tests could establish that adaptation? Or maybe even more to the point, can one make such an engineered organism permanently unable to make its way in nature, or to pass on its new trait to those that are able to survive on their own?" (2) Since plants seem to be very good at developing (or finding) resistance genes that nullify chemical herbicides of all kinds, and microorganisms seem to be very good at developing (or finding) genes that circumvent disease resistance genes in plants, I wonder if resistance to the product of this engineered Klebsiella might also develop or be found to be already present in some species? [This question seems to have been pretty well answered from a practical point of view by the experiments listed in today's email from Katie Monson, so maybe it is irrelevant. But I'm still curious about the possibility, although I don't know whether such an experiment would be worth the trouble and expense.] I'm well out of my depth in these speculations; maybe someone with more knowledge than I can comment on them. Don Duvick