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Agnet April 13/04
Scientists “beef up” plant-dwelling bacteria to boost phytoremediation
India becoming a GM-trashbin
Farmers, scientists urge government to resist anti-GMO lobby
GM corn planting must allot area for natural corn
Nutritional and safety assessments of foods and feeds nutritionally
Evaluation of Bt corn on mouse testicular development by dual parameter flow cytometry
Gene silencing creates hypoallergenic plants
Protectionism influences refusal to use GM foods
Introduction of GM crops into crop centers of origin and diversity
Scientists finding ways to outsmart crop-damaging bugs
University of California researchers test genetically modified alfalfa
Mississippi State University and Toxin Alert Inc. sign an agreement for thedevlopment of large-scale plantibody production
Ottawa wants to lift bee ban: Killer bees feared
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Scientists “beef up” plant-dwelling bacteria to boost phytoremediation
April 11, 2004
Brookhaven National Laboratory
http://www.bnl.gov/bnlweb/pubaf/pr/2004/bnlpr041104.htm
UPTON, NY — Using plants to soak up and degrade environmental pollutants, a strategy known as phytoremediation, can be more successful in theory than in practice — the accumulated pollutants or their metabolites sometimes kill the plants or evaporate via the leaves back into the atmosphere. But scientists at the U.S. Department of Energy’s Brookhaven National Laboratory and their collaborators in Belgium think they’ve found a way to improve the process: transfer genes from pollutant-degrading bacteria into bacteria residing in the plants. They describe their proof-of-principle experiment, in which test plants inoculated with the “beefed-up” bacteria increased the degradation of toluene, in the May 2004 issue of Nature Biotechnology, available online April 11.
“By introducing genes for the appropriate degradation pathways into natural plant-dwelling bacteria, known as endophytes, we should be able to tailor-make plants capable of cleaning up a variety of organic pollutants,” said Brookhaven biologist Daniel (Niels) van der Lelie, one of the lead authors on the paper. He also envisions introducing pollutant-degrading pathways into bacteria that live in crop plants to reduce the residues of pesticides and herbicides that make their way into our food.
Van der Lelie maintains that the technique should win widespread acceptance because it uses only naturally occurring bacteria and natural gene-transfer methods.
The scientists started with a type of bacteria that naturally colonizes the roots and stems of their test plant, yellow lupine. They mixed these bacteria with a related soil-dwelling strain known to degrade toluene. This allowed the strains to share genetic material through a natural process known as bacterial conjugation.
They then selected for the endophytic bacterium that had acquired the capability to grow on toluene, and used this strain to inoculate yellow lupine plants. After allowing the inoculated plants to grow for 21 days, the scientists analyzed the bacterial content of their roots and shoots using selective growth media containing toluene to confirm plant colonization by the so called “ENDEGRADER” bacteria.
The scientists then compared the ability of these plants to grow in an environment containing toluene (both hydroponically and in non-sterile soil in greenhouse studies) with that of non-inoculated plants and plants inoculated with the soil bacteria. They also measured the amount of toluene released from the plants’ leaves via evapotranspiration.
Plants inoculated with endophytic bacteria that had acquired the toluene-degradation pathway were able to grow in the toluene-contaminated environment under both hydroponic and greenhouse conditions, even when the levels of toluene present killed the other test plants. Furthermore, plants inoculated with the toluene-degrading endophytic bacteria released three to four times less toluene into the atmosphere.
“These results confirm our hypothesis that endophytic bacteria, when equipped with the appropriate degradation pathway, can help plants survive under conditions with elevated levels of pollutants, and improve the performance of plants used to remove these contaminants from the environment,” van der Lelie said.
The next step will be to test the technique in poplar and willow trees, deep-rooting species already used in phytoremediation. “In trees, the time between the uptake of the pollutant by the roots and its arrival in the leaves can take several hours to days, allowing sufficient time for efficient degradation by endophytic bacteria in the plant tissue,” van der Lelie said.
The scientists have already isolated 150 bacterial species that live as endophytes in poplar and are beginning experiments to see which will be most amenable to gene transfer. The bacteria containing the degradation pathways will be isolated from contaminated environments.
The collaborators on this research, which is part of the European Research Project ENDEGRADE, are from the University of Limburg (LUC) in Diepenbeek, Belgium, and the Flemish Institute for Technological Research (VITO), where Daniel van der Lelie and his wife Safiyh Taghavi hold joint appointments and where they initiated this research. The work was supported by the European Commission under the Fifth Framework Program, Quality of Life; the Ford Motor Company; and Brookhaven Laboratory discretionary funding.
India becoming a GM-trashbin
April 13, 2004
The New Nation
Devinder Sharma
As the world wakes up to human health and environment nuisance from the genetically modified (GM) crops, India is, according to this story, fast turning into a dustbin for the new technology.
In March, Western Australia became the first Australian state to ban outright planting of GM food crops. Its Premier, Geoff Gallop, said he did not want to jeopardise his state’s canola industry at a time when international consumer sentiment was opposed to GM crops. Within a few days of this decision, Victoria imposed a four year moratorium on the cultivation of GM oilseeds rape to “protect its clean and green” image. South Australia and Tasmania have already banned GM crops. Four states imposed a moratorium on growing GM crops in a space of five days.
In the United States, Mendocino county in California became the nation’s first to ban the raising and keeping of genetically engineered crops or animals. In March, the hilly state of Vermont, in a historic decision, voted overwhelmingly to support a bill to hold biotech corporations liable for unintended contamination of conventional or organic crops by genetically engineered plant materials. This bill is the first of its kind in the world that aims to protect a farmer from being sued by the seed companies if his crops are contaminated with GMO material.
In Britain, the dramatic turnaround by Bayer Crop Science to give up attempts to commercialize GM maize, have ensured that the country remains GM free till at least 2008. Despite Tony Blair’s blind love for the industry, tough GM regulatory regime came in the way of the adoption of the technology. In Japan, consumer groups announced their intention to present a petition signed by over 1,000,000 people to Agriculture and Agri-Food Minister, Bob Speller. The petition calls for a ban on GE wheat in Canada. Japan is one of the biggest markets for Canadian wheat.
In April, however, the Genetic Engineering Approval Committee (GEAC) in India approved another Bt cotton variety for the central and southern regions amidst reports that the go ahead came without adequate scientific testing. The approval also comes at a time when the US Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) is seeking public comment on petitions from Mycogen Seeds to deregulate two lines of genetically engineered insect-resistant cotton. APHIS is seeking public comment on whether these cotton lines pose a plant pest risk.
Such has been the casual approach to regulate the most-controversial technology that it has become practically difficult to keep track of the new GEAC chief. They keep on changing at a pace faster than that expected from musical chairs. At the same time, while Britain had set in place a tougher regulatory regime making the companies liable for any environmental mishap, India continues to ignore the warning. The regulations that the GEAC had announced at the time of according approval to Bt cotton in 2002 were only aimed at pacifying the media. The GEAC has not been held accountable for the deliberate attempts to obfuscate the public opinion in an effort to help the seed industry make a fast buck.
Farmers, scientists urge government to resist anti-GMO lobby
April 13, 2004
Philippine Star
Leading Filipino scientists and farmer organizations were cited as recently calling on the government "to resist a new wave of pressure from anti-GMO lobbyists who are on an apparent campaign to derail the country’s bid for food sufficiency".
The leaders said the recent botched attempt by foreign anti-GMO lobbyists to link ailments among local tribesmen to genetically-modified corn crops may be a sign that the government policy on biotechnology "may not have been beneficial to some foreign business interests."
The Arroyo government adopted the use of biotechnology in 2002 in a bid to improve farm productivity while reducing the need for chemical applications. It also approved the domestic propagation of the high-yielding Bt corn variety following field test results that it can raise production by up to 40 percent with less chemical insecticide application. The policy, however, was opposed by Europe-based groups.
Recently, Filipino scientists and farmers groups have questioned allegations by Norwegian anti-GMO campaigner Terje Traavik that certain respiratory ailments among B’laan tribesmen in Mindanao were caused by the high-yielding pest-resistant Bt corn variety. Health officials also belied the claims. Leading Filipino scientist and University of the Philippines medical expert Nina Barzaga urged Traavik to desist from "engaging in a scare campaign unless his claims can be substantiated using scientific methodology".
Barzaga said the allegations need to be evaluated "based on the principles of immunology and immunobiology." Barzaga is a professor of medical microbiology and microbial immunology at the University of the Philippines in Manila.
GM corn planting must allot area for natural corn
April 13, 2004
The Manila Bulletin
Melody M. Aguiba
Propagators of the genetically modified (GM) corn technology in the Philippines will, according to this story, abide by a new government regulation mandating the reservation of 20 percent of every 200 hectares of contiguous corn field for non-GM corn varieties aimed at maintaining the resistance of GM corn against pests.
Samuel C. Dalmacio, research manager and plant pathologist of Du Pont’s Pioneer HI-Bred Philippines Inc. (PHBP), was cited as saying the regulation of the Bureau of Plant Industry (BPI), lead agency for GM product propagation, will take effect two years after the issuance of a memorandum circular issued by the government last December 2003, adding, "The government wants to maintain the effectivity of Bt corn because they’re afraid that if all farms are planted with it by 100 percent, the selection pressure on the ACB (Asiatic corn borer) population may increase which may lead to the development of insect resistance against Bt corn."
With such fear, Dalmacio said the government has opted to adopt an 80 percent GM crop and 20 percent non-GM land ratio. The system, he said, is being adopted in the United States, technology leader in GM propagation where majority of the estimated 9.1 million hectares of Bt corn area worldwide is planted.
Nevertheless, he said that since the introduction of Bt corn technology in the US in 1996 and the replication of the technology in about 10 countries worldwide, no insect-resistance has so far been observed in any corn field.
Nutritional and safety assessments of foods and feeds nutritionally
April 12, 2004
AgBioWorld
http://www.checkbiotech.org/root/index.cfm?fuseaction=news&doc_id=7549&start=1&control=209&page_start=1&page_nr=101&pg=1
The global demand for food is increasing because of the growing world population. At the same time, availability of arable land is shrinking.
Traditional plant breeding methods have made and will continue to make important contributions toward meeting the need for more food. In many areas of the world, however, the problem is food quality. There may be enough energy available from food, but the staple foods lack certain essential nutrients. In the developed world, demand for 'functional foods' (that is, foods that provide health benefits beyond basic nutrition) is increasing. Nutritional improvements in foods could help to meet both of these demands for improved food quality.
Modern agricultural biotechnology, which involves the application of cellular and molecular techniques to transfer DNA that encodes a desired trait to food and feed crops, is proving to be a powerful complement to traditional methods to meet global food requirements. An important aspect of biotechnology is that it provides access to a broad array of traits that can help meet this need for nutritionally improved cultivars. The new varieties developed through modern biotechnology have been identified by a number of terms, including genetically modified (GM or GMO), genetically engineered (GE or GEO), transgenic, biotech, recombinant, and plants with novel traits (PNTs).
Evaluation of Bt corn on mouse testicular development by dual parameter flow cytometry
April 2004
J. Agric. Food Chem., 52 (7), 2097 -2102
Denise G. Brake, Robert Thaler, and Donald P. Evenson (Forwarded by Sonny Ramaswamy)
Via AgBioView at www.agbioworld.org
The health safety of Bt (Bacillus thuringiensis) corn (Zea mays L.) was studied using mouse testes as a sensitive biomonitor of potential toxic effects. Pregnant mice were fed a Bt corn or a nontransgenic (conventional) diet during gestation and lactation. After they were weaned, young male mice were maintained on the respective diets. At 8, 16, 26, 32, 63, and 87 days after birth, three male mice and an adult reference mouse were killed, the testes were surgically removed, and the percentage of germ cell populations was measured by flow cytometry.
Multigenerational studies were conducted in the same manner.
There were no apparent differences in percentages of testicular cell populations (haploid, diploid, and tetraploid) between the mice fed the Bt corn diet and those fed the conventional diet. Because of the high rate of cell proliferation and extensive differentiation that makes testicular germ cells highly susceptible to some toxic agents, it was concluded that the Bt corn diet had no measurable or observable effect on fetal, postnatal, pubertal, or adult testicular development.
If data from this study were extrapolated to humans, Bt corn is not harmful to human reproductive development.
Gene silencing creates hypoallergenic plants
April 9, 2004
Drug Week
http://www.NewsRx.net
Via AgBioView at www.agbioworld.org
According to a study from Australia, "pollen of many grasses, trees, and weeds are the source of inhalant allergic proteins while various other plant products are allergenic only upon their ingestion as a food source. Allergenic proteins of pollen are exposed to human immune system after their rapid release from pollen upon coming in contact with moist surface of nasal mucosa. The advent of molecular cloning and ability to genetically transform plants now offer unprecedented opportunities to produce hypoallergenic plants by targeted switching off allergen production."
"Gene silencing strategies that operate at post-transcriptional level are highly suitable for blocking allergen production. We have demonstrated the concept of allergen gene silencing through antisense approach by producing ryegrass plants that do not produce major allergen in its pollen. Our results show the potential of antisense approach in reducing the allergenic potential of plants," according to P.L. Bhalla and colleagues, University of Melbourne, Institute of Land Food Resources.
"Such a strategy can have a general applicability for production of transgenic plants depleted of both inhaled and ingested allergens. In addition, such an approach could also help in elucidating the in vivo function of allergen(s) in plants and contribution of an allergen to overall allergenic potential of an allergen source," researchers predicted. Bhalla and colleagues published their study in Methods (Knocking out expression of plant allergen genes. Methods, 2004;32(3):340-345).
Protectionism influences refusal to use GM foods
April 8, 2004
The Wall Street Journal (Letter)
John Bamberger
Via AgBioView at www.agbioworld.org
Your April 2 editorial on Angola's refusal to accept genetically modified crops is very disturbing. The same European countries that "recommend" to these starving countries to not accept GM grain or seed contributions is not based on science but on protectionism.
European companies such as Syngenta, Bayer Crop Science, BASF, Lima Grain Genetics, etc., have been doing wonderful seed research projects with great potential to mankind, including genetic modification, right here in the U.S., for dozens of years, So why would they do this if GMs are dangerous? Protectionism: Monsanto Co. was the first to market with GM foods and the European companies fell behind and then started the Frankenfood scare tactics to play catch-up.
As a supplier to seed research companies, universities and traditional plant breeders around the world, I have firsthand knowledge of the extent of these programs and their potential to help starving countries around the world. Now that several plants' DNA has been mapped, the future of grain production is amazing: drought resistant plants and freeze resistance plants are currently being developed. Imagine grains grown almost anywhere.
Introduction of GM crops into crop centers of origin and diversity
April 13, 2004
Special to AgBioView
C Kameswara Rao and S Shantharam
http://www.agbioworld.org
Critics of the use of GM technology for crop improvement argue that the introduction of transgenic (GM) varieties into the Centres of Origin (CO) and/or Centres of Diversity (CD) of the concerned crop plants would eliminate the existing diversity and impoverish natural genetic resources. This is scare mongering that has now become an emotional and sentimental issue of serious proportions, but is bereft of any rationality, with science being paid a Nelson’s eye.
There is certainly a possibility of transgenics and their wild or cultivated relatives inter-crossing in nature. Since this is a very broad generalization, only a crop-wise and region-wise scientific evaluation of possible events and their consequences should guide our decisions and not rhetoric.
Centres of Origin of cultivated plants are identified on the basis of the number and diversity of wild species as well as the number of endemic species of the concerned genus in a given region, while the Centres of Diversity are recognized on the basis of the number and diversity of different varieties, wild and cultivated, of the species. The Centres of Origin and Centres of Diversity of crop plants as known to us are largely based on circumstantial evidence. In the cases of crops that are extensively cultivated over wide geographical ranges, a large number of new varieties were continuously developed, involving a large number of parents, making the issues virtually intangible. For example, IR-64 rice appears to have had more than 100 parents, with consequent extensive genomic rearrangements, some natural and the others induced.
It is often forgotten that species are placed in the same genus based on various taxonomic criteria and this does not necessarily mean that all the species in a genus are genetically related to each other. Genetic relationship of species and varieties should be determined on the basis of the degree of crossability. For species to interbreed producing fertile offspring with ease, their genomes should be compatible. Such considerations did not enter the early taxonomic treatments or the current criticism.
For various natural causes, the number/diversity of species/varieties in the CO may dwindle in time while the same species/varieties may be very successful in their new homes, which are not the CO. Hence CO and CD need not necessarily be the same. It is not a settled issue that India is a CO of rice while it is certainly a CD. So far as cotton is concerned it is neither a CO nor a natural CD.
Desired genes from the gene pools of crop plants need not be sourced from living plants from the CO or CD. They may come from anywhere, such as collections in research institutes, gene banks, pollen banks or such ex situ sources. The seed in various collections may not be viable after a time, but with the deployment of techniques of molecular biology, any gene(s) from any source can now be isolated and utilized.
Distinctness of species and varieties is maintained in nature by the operation of reproductive barriers in various forms. If all species, even of the same genus, can intercross freely in nature, we would not have had so many wild species considered as related to the cultivated species. Varieties of a crop plant species may cross with each other in a greater frequency than species, but even this is not of such a common occurrence. Farmers have maintained the distinctness of varieties crops, of even those that interbreed freely in nature. Cabbage, cauliflower, Brussels' sprouts, broccoli and knoll-kohl are taxonomic varieties of the same species Brassica oleracea. Grown in the proximity of each other and unattended, these crops freely interbreed and lose their identity in a few generations, because they are not reproductively isolated from each other. For over a couple of centuries, farmers have maintained distinct, not just these five crops, but several cultivars under each of them, which is not an easy task. Most other crop plant species do not pose similar difficulties.
If natural hybridization is a rare event, it is proportionately difficult under experimental conditions. It was estimated that it needed over 100,000 artificial crosses performed by several research groups over several decades, before a successful hybrid between Raphanus and Brassica was produced. It involved a dogged pursuit of over 100 years to produce a fertile Triticale by a very large number of plant breeders.
It is possible that there may be a few instances of natural hybridization in otherwise non-crossing species. But a few chance hybridizations do not mean anything unless the hybrids produce fertile offspring from the first generation onwards, and can back- cross. Even after such introgression, unless the new characters have an adaptive value, the new gene combinations do not survive in nature. Alternatively, plant breeders should select them for their agronomic or economic potential. Actually this was what has happened before artificial means of crop improvement were developed.
If transgenic varieties hybridize with their wild or cultivated relatives in nature, the frequency of such events cannot be more than what has been happening in nature, before the introduction of transgenics into the environment. It is an absurd contention that transgenes enhance the promiscuity of crop plants.
Since rice and cotton crops are often at the forefront of arguments against the introduction of transgenics of these crops into the environment through commercial cultivation, more particularly into areas supposed to be rich in diversity, issues related to these two crops are discussed here.
RICE
Of about 25 species in Oryza, the following species have genomes designated AA, similar to that of Oryza sativa, the cultivated species (the additional areas of distribution are given in parenthesis):
Tropical Australia: Oryza meridionalis (AA) Endemic; Oryza rufipogon (AA)
(Tropical Asia)
Tropical Asia: Oryza nivara (AA) (India); Oryza rufipogon (AA)
(Australia)
India: Oryza nivara (AA) (Tropical Asia); Oryza rufipogon (AA)
(Australia)
Tropical Africa: Oryza barthii (AA) Endemic; Oryza longistaminata (AA)
Endemic
West Africa: Oryza glaberrima (AA) Endemic?
Central and South America: Oryza glumaepatula (AA) Endemic
While considering the introduction of rice transgenics into a particular area, reliable data on the accurate distribution of these species are essential. Several of these species are endemics and so are of concern only in the respective regions.
The following is a set of results of experimental inter-specific hybridization in Oryza, with the percentage of seed set given in parenthesis. The species listed are pollinators while the cultivated Oryza sativa was the female parent.
1. Oryza sativa complex (genome AA; diploids); Oryza nivara (9.1 to 56.7);
Oryza rufipogon (18.5 to 73.0)*; Oryza glaberrima (29.5 to 56.7)
2. Oryza mayeriana complex (genome not designated; diploids); Oryza
mayeriana ssp. granulata (zero)*
3. Oryza ridleyi complex (genome not designated; tetraploids) ; Oryza
ridleyi (0.0 to 7.7)*
4. Oryza officinalis complex (diploids); Oryza officinalis (CC; 5.9 to
17.3)*; Oryza australiensis (EE;0.5 to 3.8)*; Oryza latifolia (CCDD; 0 to
25)*; Oryza grandiglumis (CCDD; 6.7)*
5. Not in any complex Oryza brachyantha (FF; 0 to 1.1)*
*Embryo rescue techniques were needed for the recovery of seed of these crosses.
No data are available on the viability of this first generation seed and on the subsequent generations.
Only Oryza nivara and Oryza rufipogon have produced hybrids with Oryza sativa, with seed set of any significance. Interspecific hybridization between the cultivated and wild species does not seem to occur in nature. Hybrids of Oryza sativa with species even in the same genome group are highly sterile and may require embryo rescue. Such hybrids cannot survive in nature.
For the following reasons the impact of the introduction of new rice varieties in the CDs of rice is manageable, with a few precautions in place:
1. Commercial varieties of Oryza sativa are neither normally sympatric nor naturally panmictic with the wild species of Oryza.
2. Rice is a predominantly self-pollinated crop. The viability of rice pollen is only for about five minutes and the receptivity of the stigma is about 20 minutes, though the florets may remain open for over an hour. The distance of horizontal dispersion pollen is short, about six to seven meters. Even if it is 100 meters, a mere dispersion of pollen, if they are not viable, is of no consequence.
3. Data on the distribution of the wild species are generally vague. Generalized descriptions as 'South India' or 'Tropical Asia' or 'Central America', are misleading. The wild species have a pronounced disjunct distribution and appear and disappear, in the same area, time and again. Even within a particular country, precise data on the distribution of the wild species are needed. For example, in India, the distribution of Oryza meyeriana is given as 'Southern, Eastern and North Eastern India'. but the species occurs only in small isolated pockets and not throughout these regions. The introduction of new varieties needs to be done cautiously only in the pockets of the occurrence wild relatives. Even then, a separation distance of 20 meters eliminates the chances of contamination and even 10 meters makes it unlikely.
4. Planting a refuge of some species which are taller the than the rice plants, around the field of the transgenic variety will provide a pollen screen. If these species are of some of economic importance (such as green manure), the farmer derives an additional benefit. Since rice grows in waterlogged conditions for most part, a non-rice refuge within the rice field is not a workable proposition.
5. The spread of the introduced genes requires positive selection potential in the hybrid background. Granting this, genes for nutritional enhancement such as _-carotene, iron and others, do not cause any adverse impact on the environment. Genes for herbicide tolerance operate only when triggered by the herbicide. Since rice plants cannot hybridize with any other grass species, introduction of transgenes for herbicide tolerance, abiotic stress such as salt, drought, shade and flood tolerance, are not of any appreciable consequence. Rice is a very delicate crop requiring great care. Even if any of these genes get incorporated into other varieties of rice, the chances of survival of these hybrid swarms and the consequences of that event cannot be alarming. Transgenics with such genes are any way meant for introduction in small areas.
6. It is actually necessary to bring transgenic (GM) varieties of rice into large-scale cultivation in order to understand the probable problems and to device mechanisms to contain them. The problems, if any, are easily taken care of, if the impact of the new varieties is evaluated case-by-case, region-wise.
7. To a naturally possible extent, commercial varieties of rice have been exchanging genes among themselves and with the wild species of Oryza all along and there is no evidence of the hybrids surviving to any considerable extent or of having any significant impact on the environment.
8. In conclusion, while caution should certainly be the watch word, there are no alarming possibilities that warrant a blanket ban on the introduction of transgenic (GM) rice for commercial cultivation..
COTTON:
Since 1890, when the first hybrids of cotton with superior qualities were produced, cotton breeders have put in enormous efforts and time to continuously develop inter-specific and inter-varietal hybrids, with the result the current cultivated cottons cannot be ascribed to any taxonomic species. They never existed in nature as they are synthetic and have not evolved through natural means.
Species of Gossypium and cultivated cotton are only rarely sympatric. In India, the only wild species is Gossypium stocksii, a migrant from the Middle East, which occurs in North Western Gujarat, where cotton is not cultivated.
Cotton pollen are among the heaviest in the angiosperms, with about 70 per cent of hydration. They are spinescent, sticky and tend to clump. This and the structure of the cotton flower make it extremely difficult for the cotton pollen to be wind borne. Cotton being a self- pollinated crop, the chances for cross-pollination are quite low. The refuge takes care of any pollen drift.
The most prominent and controversial transgenes in cotton are the Bt genes for pest resistance. Natural hybrids between species of Gossypium and cultivated cotton varieties are not a common event. There can be some small degree of hybridization between the transgenic and the cultivated cotton varieties, but this cannot be more than what has been happening in nature, among the cotton varieties, all the time. Even in such a rare event, even if the Bt gene is transferred to another variety of cultivated cotton, how can the consequences be catastrophic? In fact, such an event amounts to a free transfer of expensive and time-consuming technology without the burden of the regulatory process. If we are innovative we can make the best use of the situation.
The scientists should provide information to answer the arguments against introduction of transgenics into CO and CD. Otherwise, the public would get misled and avoidable opposition, based in ignorance and/or misinformation, builds up.
--
C Kameswara Rao is at Foundation for Biotechnology Awareness and
Education, Bangalore, India; krao@...; and S Shantharam is at
Biologistics International, Ellicott City, MD, USA;
sshantharam@...
Scientists finding ways to outsmart crop-damaging bugs
April 13, 2004
Purdue University
A new screening method aimed at boosting pesticide effectiveness may be commercially viable, according to Purdue University researchers.
The process is designed to identify chemical compounds that could be added to current pesticides to overcome resistance insects have developed to them. In a recent issue of the journal Pesticide Biochemistry Physiology, the scientists report that the method will be applicable to a variety of insects and chemicals.
"It's becoming more and more difficult to find new, effective pesticides," said Barry Pittendrigh, assistant professor of entomology and senior author of the study. "If we can kill these pesticide-resistant insects in the field, then we have the potential to increase the functional life of the insecticides currently in use."
Crop-damaging insects mutate over time so they are able to overcome the effects of chemicals developed to kill them. A toxin that protected a crop for more than a decade or two eventually may lose its lethality due to resistance in the insect population.
According to the U.S. Department of Agriculture, more than $7.5 billion is spent annually on agricultural pesticides. This is about 30 percent to 50 percent of the variable costs involved in managing harmful insects.
Pittendrigh and his research team studied common research fruit flies, Drosophila melanogaster, in which the molecular mechanism that provides the insect with chemical resistance was known. They applied that knowledge to test known chemicals' toxicity to the resistant insects.
A pesticide's toxic effect occurs when a molecule on an insect's cells, called a receptor, acts as a loading dock for molecules in the pesticide. When a toxic chemical is used, its docking molecule, called a ligand, joins the receptor and kills the bug.
But nature allows pests to challenge control methods by altering their own receptors. These biochemical changes prevent binding of the chemical to the receptor and its entry into the bugs' system. Once this occurs, the chemical becomes ineffective and a new way to stop the insects is needed.
Discovery of other toxins to attack insects that have the altered receptor offers a new way of minimizing resistance in the insect population, Pittendrigh said. The newly introduced insecticide provides negative cross-resistance, meaning the chemicals react with the mutated molecule.
"Insects have a tremendous capacity to adapt to chemicals that we use to control them," Pittendrigh said. "That's just evolution in motion. With negative cross-resistance, we're buying time for the commercial life of another pesticide. Using resistance-breaking compounds is a way to potentially double or triple the time that the original compound is effective."
In this study, the researchers tested nine related insecticides in order to identify a negative cross-resistance toxin. They found that the resistant flies were highly susceptible to one compound called deltamethrin. Use of deltamethrin dramatically reduced the numbers of pesticide-resistant insects in a fruit fly population.
The researchers used DDT (dichlorodiphenyltrichloroethane) as their base chemical because they know the insect molecule with which it reacts. This gave them insight into how other chemicals would behave.
After finding that deltamethrin was the most effective, they added the DDT. Then they tested the combined toxicity.
Though it's banned in developed countries, DDT is commonly used for mosquito control in Third World countries where malaria is still the No. 1 killer.
"In the fly line, we have a known mechanism of resistance, and we understand how DDT works at the molecular level," Pittendrigh said. "So then we can describe and understand molecularly how negative cross-resistance occurs. DDT was used simply because it allowed us to test a model system."
One argument against negative cross-resistance has been that it will be difficult, if not impossible, to find compounds toxic to mutated insects, Pittendrigh said. However, this study shows it may not be as difficult to identify negative cross-resistance compounds as once assumed.
The screening process will speed up and simplify identifying effective compounds and add another weapon in the arsenal to fight crop-destroying insects.
"If we can extend the commercial lifetime of a current pesticide with a negative cross-resistance compound, that's the best we can hope for," Pittendrigh said.
The screening system for identifying negative cross-resistance compounds has the potential to be applicable to other insects and to be produced and used at a commercial level, he said. But first, the molecular evolution of pesticide resistance in each targeted insect must be known.
For the negative cross-resistance toxin to be beneficial and financially viable, it would have to be used in cases where the evolutionary change in the target insect is seen in more than one line of the bug, which is found across a wide geographical area, Pittendrigh said. The chance of successful use of a chemical is even better if this resistance mechanism is the same across a wide variety of pest insects.
The other researchers involved in this study were: Joao Pedra and Andrew Hostetler, a doctoral student and a researcher assistant, respectively, in Purdue's Department of Entomology; Patrick Gaffney, University of Wisconsin, Madison, Department of Statistics; and Robert Reenan, associate professor, University of Connecticut Department of Genetics and Developmental Biology. Pedra and Pittendrigh also are part of the Purdue Molecular Plant Resistance and Nematode Team.
The Purdue Department of Entomology provided funding for this research.
Related Web sites:
Purdue Department of Entomology: http://www.entm.purdue.edu/
Environmental Protection Agency, DDT History: http://www.epa.gov/history/topics/ddt/01.htm
Pesticide Biochemistry Physiology: http://authors.elsevier.com/JournalDetail.html?PubID=622930&Precis=DESC
ABSTRACT
Hyper-susceptibility to deltamethrin in parats-1 DDT resistant Drosophila melanogaster
Joao H.F. Pedra,a,b Andrew Hostetler,a Patrick J. Gaffney,c Robert A. Reenan,d and Barry R. Pittendrigha,b,* - Department of Entomology, Room 100, 1158 Smith Hall, Purdue University, West Lafayette, IN 47907-1158, USA; MPRINT-Molecular Plant Resistance and Nematode Team, Purdue University, West Lafayette, IN 47907-1158, USA; Department of Statistics, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Genetics and Developmental Biology, University of Connecticut Health Center-MC3301, 263 Farmington Avenue, Farmington, CT 06030, USA
The extensively studied para gene encodes a a-subunit of the voltage-activated sodium channel in Drosophila melanogaster, which is the documented target site of DDT and pyrethroid insecticides. The parats-1 fruit fly line carries a recessive sex-linked insecticide-resistance trait (parats-1 allele) that has been defined on the basis of the behavioral phenotype of temperature-sensitive paralysis. We have determined that parats-1 confers hyper-susceptibility to deltamethrin in addition to the previously annotated resistance to DDT, revealing the presence of negative cross-resistance. We investigated the potential use of negative cross-resistance shifting parats-1 gene frequencies in D. melanogaster populations. After five generations of selection, the parats-1 allele, respectively, became more or less frequent whether Drosophila populations were selected with DDT or deltamethrin.
University of California researchers test genetically modified alfalfa
April 11, 2004
Knight-Ridder Tribune
Reed Fujii, The Record, Stockton, Calif.
California farmers have for years grown genetically modified crops, such as corn and cotton and next, according to this story, may be alfalfa, now being studied by University of California researchers on test plots throughout the state, including in San Joaquin County.
The story says that alfalfa, while it draws little public acclaim, covers about 1 million acres in California, more than any other farm crop. It is a primary feed for the state's dairy industry, which is the largest in the nation and the No. 1 farm commodity in San Joaquin County.
Critics, however, charge that high-tech alfalfa may provide only short-term benefits to farmers while creating long-term problems. They also worry that it and other genetically modified plants and animals pose unknown risks to the health of people, livestock and the environment.
Researchers are testing alfalfa modified to be resistant to the widely used herbicide glyphosate -- the active ingredient in Roundup and many other broad-spectrum weed killers. This trait allows farmers to apply glyphosate to alfalfa fields and kill weeds, while the desired crop continues to thrive.
Mick Canevari, UC Cooperative Extension farm advisor in Stockton, was quoted as saying, "It is not necessary going to be the silver bullet, but it is going to assist growers in producing high-quality alfalfa."
Top-quality alfalfa hay is what dairy operators demand for their cows, discounting feed that contains weeds with no nutrition value or that might be even toxic.
Kenny Watkins, president of the county Farm Bureau Federation and who raises alfalfa and other field crops, as well as walnuts and cattle near Linden, was quoted as saying, "I'm sure it's got to cheapen our production costs and make the management less intense. … The more weeds you get in it, the less clean it is, the less you can sell it for."
Canevari was further quoted as saying, "This new technology may reduced the amount of pesticides and herbicides that are needed to grow the crop and thereby reduced the risk of pesticide runoff with some of our winter-applied herbicides."
It's no panacea, however.
Canevari said he's seen stinging nettle -- a weed naturally resistant to glyphosate -- steadily gain ground in one of his test plots, now in the third year of evaluation in the Delta west of Stockton. Another worry is that other weeds may develop resistance to the herbicide.
Mississippi State University and Toxin Alert Inc. sign an agreement for thedevlopment of large-scale plantibody production
April 12, 2004
From a press release
TORONTO - Mississippi State University and Toxin Alert Inc. (TSX: "TOX"), announced today they have signed an agreement for the development of large-scale antibody production (kilogram quantities) from plants. The five-year agreement will seek out US $ 2.0 million annually in US Federal funding for research carried out between Toxin Alert and Mississippi State University in Starkville, MS, to develop commercially viable growing and extraction methods to produce antibodies and other proteins from plants. These antibodies can be used in Toxin Alert's Toxin Guard(TM) product to detect the presence of food-borne pathogens such as Listeria and E.coli in food as well as other applications. The production of antibodies in plants is also known as "plantibodies".
Dr. Edward Petroff, Exec. Vice President of Toxin Alert Inc., said " This agreement is a wonderful example of public and private co-operation in the development of science and technology which will be very important to general public health, both in the United States and Canada and world-wide. Toxin Alert has been funding laboratory and contained field research at the University of Guelph in Ontario, Canada, for several years, and it is great to have Mississippi State University join us to expand and commercialise our plantibody production efforts."
www.toxinalert.com
Ottawa wants to lift bee ban: Killer bees feared
April 13, 2004
National Post
A2
Tom Blackwell
The federal government wants to lift a 17-year-old ban on importing live bees from the United States to help a struggling honey industry here, but, according to this story, critics fear the move could open the door to so-called killer bees and their frightening ways.
Officials have unveiled a proposed regulation that would allow beekeepers to import queen bees and their "attendants" from the United States to replenish depleted stocks.
In a dispute that has pitted most Western Canadian honey producers against their cohorts in central Canada, opponents worry that opening the border will usher in more parasites and diseases that have proven resistant to chemical treatment in the United States, as well as the killer bees.
But supporters of the move say the threat of infestation is minimal, and the warnings about aggressive Africanized bees is nothing but "fear mongering."
"It's an extremely divisive issue," said Rob Currie, an entomologist at the University of Manitoba and member of the Canadian Honey Council. "Anytime you have a border issue, it can have a huge impact on an industry and how it's run."
Agnet is produced by the Food Safety Network at the University of Guelph and is sponsored by the Ontario Ministry of Agriculture and Food, Plants Program at the University of Guelph, Agricultural Adaptation Council (CanAdapt Program), AGCare, Canadian Council of Grocery Distributors, ConAgra Foods Inc., Meat Livestock Australia, Pioneer Hi-Bred Limited (Canada), Monsanto Canada, National Pork Board, Syngenta Seeds, Inc. USA, JIFSAN, CropLife Canada, Canadian Animal Health Institute, Burger King Corporation, Southern Crop Protection Association, Ag-West Biotech Inc., Ontario Agri-Food Technologies, Syngenta Crop Protection, Feedlot Health Management Services, Institute of Environmental Science Research Limited , National Food Processors Association, Tactix Government Consulting, Inc., CanAmera Foods, Global Public Affairs, and Agri Business Group, Inc.
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