In This Issue:
ISB Upgrades World Wide Website
Use of Transgenic Commodities in Foods: Resistance and Response
Transgenic Plants That Detoxify Mercury
Beyond Coat Proteins
Expression of Foreign Genes in Transgenic Fish
It's Not Just Plants Anymore
Success for Agbiotech - Look to Monsanto
For the past few weeks, Information Systems for Biotechnology has been preparing to convert its internet services to a new platform that will more efficiently serve our users. The new Windows NT system now online will be easier to maintain and provide a solid base for future applications.
As frequent users know, the ISB website is a bit different from most in that ISB maintains online searchable databases. Most of these databases use data supplied directly by other sources, such as USDA/APHIS, or they are maintained under contract to ISB. The new operating system will allow ISB to do away with the telnet-based interface that was used to access the databases. Now, all of the database access programs have been rewritten to take advantage of standard web tools. With the click of a mouse button, scrollable menus, "radio buttons", checkboxes and text entry boxes make database searching easier than ever before. Search results are presented onscreen in standard web format and can be printed or saved to a file automatically downloaded to your computer. Databases which are available include:
The Compendium of ISB/NBIAP News Report Articles is a collection of over 1100 articles dating back to the earliest issues of the News Report from 1989. The database allows users to quickly search for past articles using keywords. It's especially useful for tracking the history or evolution of a particular topic, product, issue or development in agbiotech, such as Bt or the Flavr-Savr tomato.
As is the case with most good websites, the ISB site will continue to evolve to serve the needs of its users. In the coming months, we hope to introduce better site-wide keyword search capacity, new documents, and faster access to data. But the best way for us to improve the system is to hear from you. Your suggestions, criticisms and kudos can help us provide better services to you. Please take a look at the ISB website at http://www.isb.vt.edu and email me at nbiap@vt.edu with your suggestions as to how we can improve our coverage of agricultural and environmental biotechnology.
Doug King
Information Systems for Biotechnology
USE OF TRANSGENIC COMMODITIES IN FOODS: RESISTANCE AND RESPONSE
A trade association representing food retailers and wholesalers in 20 European countries has taken a stand against purchasing U.S. soybeans this year unless genetically engineered soybeans are clearly separated and labeled. At a news conference in Washington October 6, a spokesman for EuroCommerce warned that several of the organization's major members would not buy soybeans from the U.S. without assurance that they would not receive genetically altered ones.
The European Union (EU) has already approved entry of Monsanto's herbicide tolerant Roundup Ready soybeans, which are likely to arrive mixed in with conventional soybeans. EU approval for Bt corn is still pending, due to opposition by 13 of the 15 EU members. In Switzerland, the two biggest food retailers are likewise demanding that the U.S. producers separate transgenic soybeans so that all derivative products can be labeled. Entry into the country, a non-EU member, is being fought by Greenpeace and other environmental groups which are petitioning the Swiss government to bar imports of any genetically engineered foodstuffs.
Back in the States, the Chicago Board of Trade, the world's largest futures market, has said it would accept the genetically modified corn and soybeans to satisfy its grain contracts. Cargill and Archer Daniels Midland, major U.S. exporters, said they will accept the soybeans from growers without reservation. Officials at Central Soya Co. will accept Roundup Ready Soybeans at all six of their crushing plants, but will reserve one of their Ohio elevators for non-engineered soybeans to allow later comparative testing in processed products.
The U.S.-based Corn Refiners Association announced that food and feed products derived from Bt corn meet all current safety regulations of the FDA, USDA, EPA, and the European Union. The group's policy states that no statutory, regulatory, compositional, environmental, food or feed safety issues exist to prevent utilization of Bt corn, as approved by the U.S. government, in the corn wet milling industry.
At the same Washington news conference, consumer activist Jeremy Rifkin, head of the Foundation on Economic Trends (FET), announced that FET has targeted 10 food products for a worldwide boycott unless the makers pledge not to use any genetically modified soybeans or corn. Companies producing Kraft salad dressings, Coca Cola, Nestle Crunch, Quaker Oats corn meal, Green Giant Harvest Burgers, Similac infant formula, Karo corn syrup, MacDonald's french fries, Fleischmann's margarine, and Fritos were warned that if their food products contained any Roundup Ready soybeans (Monsanto) or Bt corn (Ciba Seeds/Mycogen), consumers would be called to boycott the products.
Rifkin asserted that consumers may suffer allergic reactions to the genetically altered herbicide tolerant soybeans, and that their use will lead to greater applications of chemicals in agricultural fields. Widespread use of corn engineered with Bt genes for control of European corn borer, he argued, would undermine the effectiveness of a valuable biopesticide by allowing insects to become resistant to it.
Monsanto disputes the allegations against Roundup Ready soybeans. The company points out that the potential for allergic reactions was evaluated as part of the regulatory approval process. Reviews in Japan, Europe, and South America similarly concluded that a person not allergic to soybeans will not be allergic to the herbicide tolerant variety. The company also maintains that total herbicide usage will decrease because farmers will be able to use Roundup herbicide. In a low-key response to Rifkin's letters threatening a boycott, Monsanto has talked with the food companies to make sure they understand the product.
The Institute of Food Technologists (IFT) responded to the news conference by issuing a press release asserting that there is no scientific evidence of environmental and health risks associated with gene-spliced soybeans and corn, and that Rifkin's allegation of such hazards is without merit and his call for labeling of modified U.S. crops is unnecessary to ensure consumer safety.
According to Joyce A. Nettleton, D.Sc., R.D., director of Science Communications at IFT, there is no evidence that genetic transfers between unrelated organisms pose hazards that are different from those encountered with any new plant or animal variety. Plants produced by rDNA technology, such as soybeans and corn, must meet exactly the same safety standards as unmodified plants or those genetically engineered by another method. In addition to complying with U.S. food safety standards, genetic engineering technologies in agriculture are compatible with conservation and protection of the environment as well as with sustainable methods of agricultural production.
IFT, founded in 1939, is a non-profit scientific society with 28,000 members working in food science, technology and related professions in industry, academia, and government (http://www.ift.org). The Institute believes that recombinant DNA technology will enhance public health and environmental protection by:
Pat Traynor
Information Systems for Biotechnology
traynor@nbiap.biochem.vt.edu
Pollution of air, soil and water with toxic metals such as lead, arsenic, mercury and zinc is a major environmental problem that poses a significant threat to human health. Increasing industrialization, automobile usage, mining and agriculture are some of the sources of toxic metal pollution (1). Mercury for example is a very common contaminant in industrial effluents and is also a component of many pesticides. Mercury leaches from the contaminated sites into the water system and often gets concentrated in the food chain. In the United States alone, the cleanup of sites contaminated with heavy metals is estimated to cost $7.1 billion (1).
While there are several ways of treating organic pollutants through degradation, there are few, if any, safe and inexpensive approaches for reducing the toxic metal pollution in our ecosystem as the metals cannot be degraded chemically. A recent report from the University of Georgia group led by Dr. Richard Meagher offers a new hope that genetically engineered plants can one day be used in our fight against metal ion pollution in the environment (2). The research article describes the efforts of Dr. Meagher's group in successfully developing transgenic Arabidopsis plants that convert toxic ionic mercury to a less-toxic vapor form.
The merA gene employed in this research is of bacterial origin and encodes the enzyme mercuric ion reductase, which catalyzes the reduction of toxic Hg2+ to less toxic, relatively inert, nonionic Hg. This gene in its native form did not function when introduced into plants. Thus, the Georgia group using polymerase chain reaction approach modified the nucleotide sequence of this gene to be more 'plant-like' by changing the codon usage, altering the flanking sequences and decreasing the total G+C content from 65% to 47%. The new merApe9 gene was introduced into Arabidopsis using the standard Agrobacterium mediated gene transformation procedure. When the resulting transgenic plants were grown in a medium laced with toxic levels of HgCl2 (5-20 ppm), they developed normally, producing flowers and seeds. The control untransformed plants, however, either did not germinate or died quickly when exposed to even low levels of mercury. Interestingly, a few transgenic plant lines seemed to prefer mercury because they grew better on media with HgCl2 while performing poorly on media without the toxic metal. The transgenic Arabidopsis plants with the mercury reductase gene were also resistant to gold ion (Au3+), suggesting a broad range of substrates for the mercuric ion reductase.
When tested with a mercury vapor analyzer, transgenic plants grown on HgCl2 medium released volatile mercury in the air, which indicates that these plants were converting the toxic mercury supplied in the nutrient medium to a vapor form. The level of such reduction to the nonionic form of mercury was seven times greater in transgenic plants than in the control plants. Further, the level of nonionic mercury evolution was directly proportional to the steady-state mRNA levels of the merA gene, providing evidence that mercury detoxification observed in transgenic plants was due to the action of the introduced gene.
Dr. Meagher's group proposes that when planted in mercury-contaminated soils, transgenic plants expressing the mercury detoxification gene may hasten the biological transformation of this toxic compound. Especially when planted around the wetlands where the mercury-problem is most acute, transgenic plants would convert the toxic mercury to less-toxic vapor form which is then released into the atmosphere where it would be further diluted through distribution. If successful under further field studies, the 'mercury-eating' plants may thus help reduce the toxic metal pollution of the biosphere. Phytoremediation through biotechnology clearly has a potential to ameliorate the excesses of other technologies.
References
1. Salt, D. E. et al. 1995. Phytoremediation: A novel strategy for
the removal of toxic metals from the environment using plants.
Bio/Technology 13:468-474
2. Rugh, C. L. et al. 1996. Mercuric ion reduction and resistance
in transgenic Arabidopsis thaliana plants expressing a modified
bacterial merA gene. Proc. Natl. Acad. Sci., USA 93: 3182-3187.
C. S. Prakash
Center for Plant Biotechnology Research
Tuskegee University
prakash@acd.tusk.edu
BEYOND COAT PROTEINS
Potatoes present more than a few challenges to researchers working to limit the impact of yield-reducing virus diseases. Besides being susceptible to infection by a variety of unrelated viruses, most commercial potato cultivars have a tetraploid genome that makes breeding for resistance a slow process. The initial genetic engineering approach of coat protein mediated resistance, effective against individual virus diseases, now is being augmented by a strategy for broad-spectrum protection against virus infection (Nature Biotechnology, November 1996).
A group from the Max Planck Institute has reported that potato plants expressing a mutant version of the potato leaf roll virus (PLRV) movement protein were resistant not only to PLRV, but to potato virus Y and potato virus X. Protection against infection by any one of these three pathogens, which belong to taxonomically distinct groups, is not due to the expression of pathogenesis-related proteins that are part of an active defense mechanism referred to as 'induced resistance'.
The transgene used in these experiments is a defective form of the PLRV movement protein, which is normally associated with the plasmodesmata of cells within phloem tissue and functions in cell-to-cell movement. The broad-spectrum resistance to unrelated viruses is thought to result from interference with systemic spread in the transgenic plants.
Pat Traynor
Information Systems for Biotechnology
traynor@nbiap.biochem.vt.edu
EXPRESSION OF FOREIGN GENES IN TRANSGENIC FISH
Commercial production of transgenic fish engineered with desirable characteristics such as enhanced growth or disease resistance is coming closer to reality in several species, including catfish, trout, salmon, carp, goldfish, and tilapia. Significant effort has been invested in preparing and evaluating vectors for expression of foreign genes in transgenic fish.
The process of developing vectors and expression systems involves identification of a suitable reporter gene as well as regulatory elements for the desired trait gene. The lacZ and CAT reporter genes have been widely used, and a recent report suggests that green fluorescent protein is also useful (1). Various promoters, including those from sockeye salmon histone H3 and metallothionein-B genes and the antifreeze protein gene promoter from ocean pout, have been used successfully to drive expression of introduced genes. A vector containing regulatory sequences from the carp beta-actin gene enhancer/promoter directed expression in nearly all tissues of zebrafish, beginning within 12 hours of fertilization (2). Similar vectors containing also the polyadenylation signal from the salmon growth hormone gene were useful for expression of foreign genes in microinjected fish eggs and fish and mammalian cell cultures (3). Most researchers agree that vectors for use in fish should contain DNA sequences from fish genes, or at least sequences from mammalian genes that are demonstrably compatible with the biochemical elements found in fish cells. In most cases, non-fish elements seem to be relatively inefficient, possibly due to improper processing of mammalian introns. Even elements from mammalian genes may be recognized inappropriately or in an unpredictable manner. For example, the high degree of sequence conservation among regulatory elements of animal beta-actin genes suggested that their function would be conserved, allowing transgenic constructs with similar transcriptional control elements to induce equivalent transgene expression in different species. However, it was found that the initiation, degree, and longevity of gene expression in zebrafish and goldfish were affected by combinations of transcriptional control elements (2). Nonetheless, non-fish elements, from both avian and insect species, have been used successfully in some cases. Optimization of transformation methods remains one of the important challenges for the immediate future of aquatic biotechnology. Improved overall integration of foreign DNA, possibly enhanced by inclusion of viral integration proteins in the transformation system, will increase the likelihood of integration into germ line cells and thus reduce the frequency of genetic mosaics.
References
1. Ivics Z, Z Izsvak, and PB Hackett. 1993. Enhanced incorporation
of transgenic DNA into zebrafish chromosomes by a retroviral
integration protein. Mol Mar Biol Biotechnol 2:162-173.
2. Caldovic L and PB Hackett Jr. 1995. Development of position-
independent expression vectors and their transfer into transgenic
fish. Mol Mar Biol Biotechnol 4:51-61.
3. Liu ZJ, B Moav, AJ Faras, KS Guise, AR Kapuscinski, and PB
Hackett Jr. 1990. Development of expression vectors for transgenic
fish. Biotechnology 8:1268-1272.
J. Glenn Songer
University of Arizona
gsonger@ccit.arizona.edu
IT'S NOT JUST PLANTS ANYMORE
This year has brought regulatory approval for releases of genetically engineered mites and nematodes. The mites, a predatory species carrying a marker gene, are being monitored for their ability to persist in Florida, disperse from the test site, and control spider mite prey. The release will be used to monitor persistence of the molecular marker under field conditions, and to demonstrate that the transgenic strain can be eliminated from the site at the end of the experiment by application of a registered pesticide. The field test is a necessary preliminary step in the long term process of developing transgenic arthropods with enhanced ability to control pests in agricultural IPM programs. USDA/APHIS issued a permit for the release in February of this year.
The transgenic nematodes are an insecticidal species engineered with the gfp (green fluorescence protein) marker gene and multiple copies of the hsp70 (heat-shock protein) gene. Wildtype nematodes tend to be less economical, stable, and effective than chemical pesticides. Introducing genes for traits that overcome these limitations may open the door to another class of improved biological control agents. The field release is designed to test the hypothesis that field persistence will be enhanced in the genetically modified strain. Upon reviewing the request for a field test permit, APHIS concluded that the transgenic nematodes did not present any risk of becoming a plant pest and therefore were not considered a regulated article under the Federal Plant Pest Act. As requested by the applicant, however, APHIS issued a Courtesy Permit to facilitate movement between governmental jurisdictions.
These two releases are undoubtedly the first of many resulting from the application of genetic engineering techniques to a broadening range of organisms. Recent advances in one sector will be highlighted at a symposium on "Transgenic Arthropods: Current Status, Future Prospects" which will be held as part of the Entomological Society of America meeting December 8-12 in Louisville, Kentucky. For registration information, connect to http://www.entsoc.org, or call the Society at 301-731-4535.
The program has been organized by Orrey P. Young (Biotechnology, Biologics, and Environmental Protection, USDA-APHIS) and David A. O'Brochta (Center for Agricultural Biotechnology, University of Maryland Institute for Biotechnology) with support from Information Systems for Biotechnology, a part of the National Biological Impact Assessment Program.
Presentations at the Tuesday, December 10th afternoon symposium include:
During the 120 day period that BE reviews and evaluates each permit application, the public also has the opportunity to review each request. BE is establishing an electronic mailing list of individuals and groups that would wish to be notified by email that a transgenic arthropod permit application has been received by the agency and is now posted on the BE home page. If you want to be included in this Transgenic Arthropod Interest Group, or have other questions, send email to oyoung@aphis.usda.gov.
Pat Traynor
Information Systems for Biotechnology
traynor@nbiap.biochem.vt.edu
The seeds were planted some 20 years ago, but after extensive nurturing and care, the tree known as "agricultural biotechnology" is beginning to bear fruit. And the public is beginning to take note, as evidenced by a story in the October 24th Edition of the Wall Street Journal entitled "Huge Biotech Harvest Is a Boon for Farmers And Monsanto" (1). For an industry that has taken some hard knocks over the years as being one that some felt would not succeed to any large extent, this article is worth noting for its positive tone as well as content.
Farmers are planting millions of acres of genetically altered crops and the net results appear to be positive. A big winner is Monsanto, which has made substantial investments in biotechnology in recent years. Farmers are taking a liking to Monsanto's Roundup (herbicide) resistant soybean, despite pockets of discontentment concerning certain sales tactics. The sales from transgenic soybean and cotton seed (another Monsanto product) are estimated at $45 million for this year, a trifling amount compared to the company's total annual revenues of $9 billion. But the products were immediately profitable and have allowed Monsanto to position themselves very well to control a dominant share of the transgenic seed market, estimated to grow to $6.5 billion in the next 10 years. These products contribute to Monsanto's agricultural products unit, which accounted for nearly 50 percent of the company's operating income last year, while making up only 25 percent of revenue.
The success of Monsanto's agricultural endeavors may ultimately lead to a refocusing of the company itself. The WSJ article notes that Monsanto is considering divesting itself of its historically prominent chemicals business to focus its efforts in the areas of agriculture, food additives, and pharmaceuticals. One driver of this strategy is the potential synergy that exists between the businesses. For example, soybeans might be developed through genetic engineering that produce high-value molecules for use in foods or as drugs.
Farmers aren't the only ones taking an interest in Monsanto. The company's stock was up 74 percent in 1995 and is up 71 percent this year. At nearly $25 billion, Monsanto's market value exceeds that of Dow Chemical Co., although Dow boasts more than twice the sales.
If transgenic crops continue to successfully produce, Monsanto's success will ride on its ability to properly promote its product and meet the growing demand. The company plans to bring pest-resistant corn and Roundup Ready cotton and corn to market in the next few years, and the current expectation is that demand will far exceed supply (1).
Reference:
1. Fritsch, P., and Kilman, S. Huge Biotech Harvest Is A Boon for Farmers And for Monsanto. The Wall Street Journal, October 24, 1996, pp. A1, A10.
William O. Bullock
Institute for Biotechnology Information, LLC
Research Triangle Park, NC
http://www.biotechinfo.com
The material in this News Report is compiled by NBIAP's Information Systems for Biotechnology, a joint project of USDA/CSREES and the Virginia Polytechnic Institute and State University. It does not necessarily reflect the views of the U.S. Department of Agriculture or of Virginia Tech. The News Report may be freely photocopied or otherwise distributed without charge. P.L. Traynor, Editor.
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