Tag Archives: gamma rays and sterilization of insects

How to Change the World: Take Seeds to Space and Irradiate them with Cosmic Rays

With 19% of the world’s population but only 7% of its arable land, China is in a bind: how to feed its growing and increasingly affluent population while protecting its natural resources. The country’s agricultural scientists have made growing use of nuclear and isotopic techniques in crop production over the last decades. In cooperation with the IAEA and the Food and Agriculture Organization of the United Nations (FAO), they are now helping experts from Asia and beyond in the development of new crop varieties, using irradiation.

While in many countries, nuclear research in agriculture is carried out by nuclear agencies that work independently from the country’s agriculture research establishment, in China the use of nuclear techniques in agriculture is integrated into the work of the Chinese Academy of Agricultural Sciences (CAAS) and provincial academies of agricultural sciences. This ensures that the findings are put to use immediately.

And indeed, the second most widely used wheat mutant variety in China, Luyuan 502, was developed by CAAS’s Institute of Crop Sciences and the Institute of Shandong Academy of Agricultural Sciences, using space-induced mutation breeding. It has a yield that is 11% higher than the traditional variety and is also more tolerant to drought and main diseases.  It has been planted on over 3.6 million hectares – almost as large as Switzerland. It is one of 11 wheat varieties developed for improved salt and drought tolerance, grain quality and yield.

Through close cooperation with the IAEA and FAO, China has released over 1,000 mutant crop varieties in the past 60 years, and varieties developed in China account for a fourth of mutants listed currently in the IAEA/FAO’s database of mutant varieties produced worldwide.

The Institute uses heavy ion beam accelerators, cosmic rays and gamma rays along with chemicals to induce mutations in a wide variety of crops, including wheat, rice, maize, soybean and vegetables….Indonesia’s nuclear agency, BATAN, and CAAS are looking for ways to collaborate on plant mutation breeding

Space-induced mutation breeding
Irradiation causes mutation, which generates random genetic variations, resulting in mutant plants with new and useful traits. Mutation breeding does not involve gene transformation, but rather uses a plant’s own genetic components and mimics the natural process of spontaneous mutation, the motor of evolution. By using radiation, scientists can significantly shorten the time it takes to breed new and improved plant varieties.

Space-induced mutation breeding, also called space mutagenesis, involves taking the seeds to space, where cosmic rays are stronger, and these rays are used to induce mutation.  Satellites, space shuttles and high-altitude balloons are used to carry out the experiments. One advantage of this method is that the risk of damaging the plants are lower than when using gamma irradiation on earth.

Excerpts from How Nuclear Techniques Help Feed China, IAEA, Apr. 4, 2019

What 200 Million Irradiated Mosquitoes Can Do

In July 2019, a combination of the nuclear sterile insect technique (SIT) with the incompatible insect technique (IIT) has led to the successful suppression of mosquito populations, a promising step in the control of mosquitoes that carry dengue, the Zika virus and many other devastating diseases. The results of the recent pilot trial in Guangzhou, China, carried out with the support of the IAEA in cooperation with the Food and Agriculture Organization of the United Nations (FAO), were published in Nature on 17 July 2019.

SIT is an environmentally-friendly insect pest control method involving the mass-rearing and sterilization of a target pest using radiation, followed by the systematic area-wide release of sterile males by air over defined areas. The sterile males mate with wild females, resulting in no offspring and a declining pest population over time. IIT involves exposing the mosquitoes to the Wolbachia bacteria. The bacteria partially sterilizes the mosquitoes, which means less radiation is needed for complete sterilization. This in turn better preserves the sterilized males’ competitiveness for mating.

The main obstacle in scaling up the use of SIT against various species of mosquitoes has been overcoming several technical challenges with producing and releasing enough sterile males to overwhelm the wild population. 

For example, the researchers used racks to rear over 500 000 mosquitoes per week that were constructed based on models developed at the Joint FAO/IAEA Division’s laboratories near Vienna, Austria. A specialized irradiator for treating batches of 150 000 mosquito pupae was also developed and validated with close collaboration between the Joint FAO/IAEA Division and the researchers…The results of this pilot trial, using SIT in combination with the IIT, demonstrate the successful near-elimination of field populations of the world’s most invasive mosquito species, Aedes albopictus (Asian tiger mosquito). The two-year trial (2016-2017) covered a 32.5-hectare area on two relatively isolated islands in the Pearl River in Guangzhou. It involved the release of about 200 million irradiated mass-reared adult male mosquitoes exposed to Wolbachia bacteria

Nei Lingding island, China (view from Hong Kong)

Experts in China plan to test the technology in larger urban areas in the near future using sterile male mosquitoes from a mass-rearing facility in Guangzhou, said Zhiyong Xi, Director of Sun Yat-sen University-Michigan State University’s Joint Center of Vector Control for Tropical Diseases and Professor at Michigan State University in the United States

Excerpts from Miklos Gaspar & Jeremy Bouye, Mosquito Population Successfully Suppressed Through Pilot Study Using Nuclear Technique in China, IAEA Press Release, July 18, 2019

How Venom from Spiders Kills Malaria Mosquitoes

In the 1980s, the village of Soumousso in Burkina Faso helped launch one of the most powerful weapons against malaria: insecticide-treated bed nets, which had early field trials there and went on to save millions of lives. But as mosquitoes developed resistance to widely used insecticides, the nets lost some of their power. Now, researchers are hoping the village can help make history again by testing a new countermeasure: a genetically modified (GM) fungus that kills malaria-carrying mosquitoes. In tests in a 600-square-meter structure in Soumousso called the MosquitoSphere—built like greenhouse but with mosquito netting instead of glass—the fungus eliminated 99% of the mosquitoes within a month, scientists report in the  magazine Science.

MosquitoSphere, Burkina Faso

The fungus also has clear advantages, however: It spares insects other than mosquitoes, and because it doesn’t survive long in sunlight, it’s unlikely to spread outside the building interiors where it would be applied.  Fungi naturally infect a variety of insects, consuming the host’s tissues in order to reproduce, and they have been used for decades to control a wide variety of crop pests….Researchers have tested dozens of different fungal strains against disease-carrying mosquitoes, but none was effective enough to pass muster. So researchers from the University of Maryland (UMD) in College Park and the Research Institute of Health Sciences & Centre Muraz in Bobo-Dioulasso, Burkina Faso, endowed a strain called M. pingshaense with a gene for a toxin isolated from spider venom that turns on when it contacts hemolymph, the insect version of blood. In the lab, the team showed its creation could kill mosquitoes faster and that just one or two spores could cause a lethal infection. 

Burkina Faso was a promising place for a field test: Unlike many countries in Africa, it has an established system to evaluate and approve the use of GM organisms. It also has one of the highest rates of malaria in the world, and insecticide-resistant mosquitoes are widespread. For those and other reasons, the U.S. National Institutes of Health funded the MosquitoSphere, which is specifically designed to test GM organisms.

Excerpts fromGretchen Vogel  Fungus with a venom gene could be new mosquito killer, Science, May 31, 2019

How to Kill the Tsetse Fly: Use Nuclear Energy

The tsetse fly’s toxic bite kills an estimated 3 million livestock annually in sub-Saharan Africa.  Farmers here used to count on losing pounds of valuable beef to the fingernail-size pest. Then veterinarians in the West African country teamed up with researchers in Austria, who work on a little-known project funded entirely by the United States.  The United States has poured about $5 million into the effort of sterilizing the male tsetse files with gamma rays.   This has led to the eradication of 99 percent of those files

Cows, Senegale. (source IAEA)

Farmer income in Niayes, Senegale,  is expected to jump by 30 percent, officials say, as more cows survive at a healthy weight. Farms, meanwhile, can now afford to buy hundreds of European dairy cows, which produce 20 times as much milkthan native breeds.  The fortune reversal sprouts from a global collaboration at the intersection of agriculture and nuclear technology

Since 2010, America has funneled roughly $379 million to Senegal’s partner in the tsetse fly fight: the International Atomic Energy Agency,…The United States earmarked an additional $560,000 this month for upkeep of the group’s laboratories in Seibersdorf, Austria.

Rather, Jeffrey Eberhardt, whom President Trump has nominated to serve as his special representative for nuclear nonproliferation, said in a May statement that the United States has maintained its backing to “expand the benefits of peaceful nuclear uses” and expressed “a firm commitment to continuing this legacy.”

The peaceful use in Senegal is called nuclear insect sterilization.  First, scientists hatch thousands of tsetse flies in an artificial habitat about 870 miles away, in the West African nation of Burkina Faso.   Next, they send the bugs to the lab in Seibersdorf, where researchers place them in tiny ionization chambers and blast them with gamma rays, rendering the males unable to pass on a healthy seed.   Finally, they chill the flies to sleep — broken wings from panicked thrashing would sabotage the mission — before tucking them into biodegradable paper boxes and shipping them to Senegal.

Excerpts from A U.S.-funded nuclear project to zap a killer fly into extinction is saving West Africa’s cows, Washington Post, May 31, 2019