South Asia's Pollution / El Nino in the Pacific / Anthrax-Eating Enzyme
This is Sarah Long. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell about an enzyme that can destroy the deadly anthrax bacterium. We tell about the effects of a weaker weather condition called El Nino. And we tell about a cloud of pollution covering much of southern Asia.
American scientists say they have developed an enzyme that can destroy the deadly anthrax bacterium. The scientists say the enzyme could effectively treat people infected with the bacterium, including drug-resistant forms of the disease. They say the enzyme also could be used to immediately identify areas thought to contain anthrax particles.
Scientists with the Rockefeller University in New York Cuty developed the anthrax-killing protein. They described their work in the British publication Nature.
Anthrax is a severe infectious disease that mainly attacks animals. However, anthrax also can infect humans. Usually, people get the disease by touching infected animals or animal products.
However, anthrax particles were blamed for five deaths in the United States last year after the September eleventh terrorist attacks. Many other people became sick. The particles were found on letters sent to political leaders and members of the media. The discovery of the letters containing anthrax temporarily slowed mail service in the United States. No suspects have yet been charged in the investigation.
The United States Defense Department provided money for the new research on anthrax. The Rockefeller University scientists developed the anthrax-killing enzyme by using a virus that attacks bacteria. Viruses can infect both humans and bacteria. Viruses that infect bacteria are called bacteriophages or "bacteria-eating viruses." They are also known as phage (fayj).
Phage are the most common life form on Earth. They can be found in soil, water or anywhere else that bacteria live. Phage have been battling anthrax and other kinds of bacteria for millions of years. Like viruses that infect humans, phage inject their genetic material into the bacterial cell. Then, the virus reproduces and bursts out before attacking the next cell.
The Rockefeller University scientists worked with phage that infect the anthrax bacterium. They identified the enzyme that allows the phage to burst out and escape from the anthrax bacterium. The scientists showed that just a small amount of the enzyme can quickly destroy a laboratory container filled with anthrax.
The scientists say this enzyme will attack only anthrax because it was developed from a phage that only infects the anthrax bacterium.
The scientists tested the enzyme on mice infected with a disease similar to anthrax. All of the mice usually die within four hours of being infected with this disease. The scientists injected the new enzyme into the mice fifteen minutes after they were infected with the disease. As many as eighty percent of the injected animals survived.
Vincent Fischetti of the Rockefeller University helped organize the study. He believes that the anthrax-killing enzyme would work as well in humans, with almost no bad effects. He also thinks the bacterium used in the anthrax attacks last year will not develop a resistance to the new treatment. That is because the enzyme is its natural enemy.
The scientists also described how the enzyme can be used to confirm the presence of anthrax particles in places like buildings. They say the test for anthrax can be done in as few as ten or fifteen minutes. Some current tests require several days to identify the presence of anthrax. The new tests are done with a hand-held light meter. The device shows glowing particles if anthrax is present.
The El Nino weather condition has returned. However, officials at the United States National Weather Service say El Nino is weaker than usual this year. El Nino is a change in the atmosphere over the Pacific Ocean. It happens every four to five years.
El Nino is Spanish for "the little one" or "the Christ child." The weather condition is called El Nino because its effects increase in December, at about Christmas time.
Normally, water temperatures in the western Pacific Ocean increase near the end of the year. This causes more rainfall in Indonesia, Australia and other nearby places. At the same time, cold ocean water causes less rainfall in the eastern Pacific Ocean, near South America. The opposite happens during El Nino. Pacific Ocean temperatures increase near South America, causing unusually high amounts of rainfall there. And, El Nino causes dry weather in Indonesia and Australia.
A strong El Nino can severely affect the weather all over the world. The last powerful El Nino was in nineteen-ninety-seven and nineteen-ninety-eight. It caused major floods around the world. El Nino also led to extremely dry weather in some areas. Reports say the weather condition caused the deaths of about twenty-four-thousand people.
So experts say having a weaker El Nino this year is good news. Weather scientists say rainfall has been higher than usual in South America. The experts say the effects of El Nino will begin in November in the United States. Drier weather is expected in the northwestern states. The northern states may have a warmer winter. But, scientists say El Nino will not be strong enough to prevent this year's powerful storms in the Atlantic Ocean.
A United Nations study says a thick cloud of pollution covering southern Asia threatens the lives of millions of people. Scientists say the pollution could increase lung diseases and cause early deaths. The cloud is also damaging agriculture and affecting rainfall levels. Scientists are calling it the Asian Brown Cloud. It has affected Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka. The pollution cloud is three kilometers high. Scientists say it can move halfway around the world in a week.
The cloud is a mixture of ash, acids, aerosols and other particles. It is the result of forest fires, the burning of agricultural waste, and huge increases in the burning of fuels by vehicles, industries and power stations.
Pollution from millions of bad cooking stoves has made the problem worse. Many poor people burn fuels like wood and animal waste in such stoves.
Scientists say the cloud of pollution appears to cool the land and oceans by blocking sunlight. They say it reduces the amount of sunlight reaching the Earth's surface by as much as fifteen percent. At the same time, heat inside the cloud warms the lower parts of the atmosphere.
Scientists say this combination could be changing winter rainfall levels in Asia. They say rainfall has increased over the eastern coast of Asia. But it has dropped sharply over parts of northwestern Asia. The report says the cloud could reduce rainfall over northwestern Pakistan, Afghanistan and western China by up to forty percent.
Harmful chemicals from the cloud are mixing with rainfall. This acid rain damages crops and trees and threatens public health. Scientists are concerned that the pollution will intensify during the next thirty years as the population of Asia increases to an estimated five-thousand-million people.
Scientists say the Asian Brown Cloud could affect other parts of the world unless steps are taken to reduce pollution. Environmental groups say action is needed to find clean, renewable energy sources.
More than two-hundred scientists took part in the U-N study. The U-N Environment Program prepared the study for the World Summit on Sustainable Development. That meeting took place in Johannesburg, South Africa. It ended last week.
This SCIENCE IN THE NEWS program was written by George Grow, Doreen Baingana and Cynthia Kirk. It was produced by Cynthia Kirk. This is Sarah Long. And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.