快猫短视频

AS THE US prepares to tighten its rules governing the production of pharmaceuticals and chemicals in genetically modified plants, some organisations are voluntarily going way beyond the existing regulations. But there are suspicions that ensuring food safety isn鈥檛 the only motive for big companies such as Monsanto.

Fears that drug-laced plants could end up in food have led to growing criticism of the US Department of Agriculture鈥檚 regulations governing pharming. The issue came to a head last year, when maize modified to produce a pharmaceutical protein was found growing in fields of normal soybeans in Iowa and Nebraska. This happened after the Texas-based company ProdiGene left seeds in the field after harvesting a crop of modified maize. In December, ProdiGene was ordered to pay around $3 million in clean-up costs and fines for violating its permit.

The incident provoked calls for tougher rules, and the USDA is carrying out public consultations as a prelude to revising its regulations. 鈥淲e have to restore public confidence,鈥� John Howard, a founder and now a consultant for ProdiGene, told 快猫短视频 at the Denver meeting. 鈥淲e need to stop treating these plants as value-added agriculture and treat them like pharmaceuticals.鈥�

For example, Howard says ProdiGene did not do enough to make sure growers were obeying the rules. As in drug manufacturing, he says, companies need to monitor the whole process from beginning to end and get it checked by an outside agency. At the moment they are not required to do this. 鈥淭here鈥檚 too much latitude in the system,鈥� Howard says.

More controversially, Howard thinks the current policy of zero tolerance for any contamination of food crops helps neither the companies nor consumers. He says the risks posed by each pharm plant should be evaluated and used to set a reasonable limit for contamination, in the same way that limits are set for the contamination with pesticides, dirt and microorganisms. 鈥淭hen, if the system breaks down and a plant escapes we鈥檒l know the level of risk,鈥� he says.

Howard cites two ProdiGene products that went on sale this year: the enzyme trypsin and enzyme inhibitor aprotinin. These proteins are normally obtained from cows, but fear of BSE has created a market for non-animal sources. Howard argues that since the proteins are found in foods such as beef offal, there is little risk if contamination does occur. He admits that work is still needed to prove that they really are harmless. 鈥淏ut I鈥檝e always argued it would be worth it,鈥� he says.

Jon McIntyre of the agribusiness giant Monsanto says his company, too, is willing to go well beyond existing regulations. Monsanto is setting up production systems for growing antibody-producing maize plants for other companies. The USDA鈥檚 proposed guidelines require pharmed maize to be separated from other corn by a distance of 400 metres, and not be planted within two weeks of any corn crop nearby, to prevent any possibility of cross-pollination. McIntyre says his team is already growing crops with four times that physical buffer and double the time lag. If necessary, the team would be prepared to increase the distance to more than 8 kilometres, he says.

Indeed, according to McIntyre, Monsanto has put in place a surprising array of safeguards that include the use of male-sterile plants that do not produce pollen, daily satellite monitoring of adjacent fields to verify the absence of maize, and dedicated harvesting and processing equipment to prevent any mixing with food.

And as extra assurance against mistakes like ProdiGene鈥檚, the Monsanto team ensures that no food crops are planted for two years in fields where pharmed maize has been grown. Instead it plants a variety of cotton resistant to a herbicide that kills any leftover maize plants. 鈥淭his is a closed-loop system completely outside of the commercial grain system,鈥� says McIntyre.

Academic institutions are also being extra cautious. Charles Arntzen鈥檚 team at Arizona State University in Tempe is inserting genes from Norwalk virus, which can cause severe diarrhoea, into plants such as tomatoes to create oral vaccines against the virus. To create the 80,000 or so doses needed for a clinical trial, the university has built a sealed greenhouse with fine-mesh screens, double doors, controlled airflow and many other features that exceed current federal guidelines. 鈥淣o insects or seeds can get in or out unless we let them,鈥� Arntzen says.

The group intends to make its plants sterile, and as a further safeguard it will use a white tomato that could never be mistaken for a food crop. 鈥淓ating it is like chewing sawdust,鈥� he says. But Arntzen worries that regulation could go too far. His oral vaccines would be most valuable to poor countries, and he thinks there should be a worldwide standard for pharming. 鈥淎 strong regulatory framework is needed that can be implemented in developed and developing countries,鈥� he says. 鈥淲e don鈥檛 want an insurmountable entry barrier.鈥�

And while companies support some tough new rules, there are other aspects of pharming that they don鈥檛 want regulated. For example, the suggestion that pharmaceutical proteins should be produced only in non-food plants is resisted by many researchers. They argue that producing the proteins in, say, tobacco would create new problems, such as the need to remove toxic alkaloids and invent new processing methods. 鈥淥ne of the great things about food is you can use off-the-shelf technology,鈥� says Arntzen. 鈥淚f you can make ketchup, you can make the vaccine.鈥� This could mean it may be eventually be possible to create vaccines for the developing world for pennies a dose, Arntzen and Howard say.

But Jane Rissler of the Union of Concerned 快猫短视频s says that the potential benefits of pharmed crops are no reason to restrict the regulations governing their growth. 鈥淚t鈥檚 important to remember they鈥檝e yet to prove they can grow these crops safely anywhere, in any country,鈥� she says.

As the USDA starts to finalise its regulations, the debate is likely to grow heated. Anti-GM activists are pushing for the toughest rules possible, and Arntzen thinks Monsanto might want to do the same. 鈥淚t raises the entry barrier to their competitors,鈥� he says. 鈥淟ooking at satellite data every day and having all that dedicated equipment 鈥� a little company can鈥檛 do that.鈥�