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Microbes go everywhere that humans do. In fact, many of them live inside and on our bodies. Most are harmless, and many are even helpful. However, some microbes can be harmful to people's health and might even pose a threat to the materials of the space station. A recent discovery indicates that microbes can remain dormant for millions of years, enough time to travel from planet to planet. Living fungal spores have been discovered at altitudes of 7 miles (11 km). An international team of scientists has recovered microorganisms in the upper reaches of the atmosphere that could have originated from outer space. According to the researchers, the living bacteria, plucked from an altitude of 10 miles (16 km) or higher by a scientific balloon, could have been deposited in terrestrial airspace by a passing comet. While microbes are just another part of everyday life here on Earth, they can be a much bigger problem on the space station. They may even be more harmful to the astronauts in space since spaceflight weakens the immune system. This means that astronauts could be more open to infection. Also, experiments have shown that bacteria grow faster in microgravity than they do on Earth. Another problem is the small area that the astronauts live in while in space. The microbes that are brought up have nowhere to go, so germs can easily be transferred back and forth between the astronauts. To reduce microbe-related problems, astronauts are tested for infection before they begin their spaceflight. They also try to cut down on exposure to germs before their mission so they don't catch anything before their launch. On the space station, equipment is used to clean the air and water. This helps protect the space station and the astronauts from microbes. Special paint and low humidity also keep microbe growth at bay on the space station. Despite these high-tech solutions, astronauts still have to clean.

Space flight has been shown to have a profound impact on human physiology as the body adapts to zero-gravity environments. Researchers have shown that the tiniest passengers (microbes) flown in space can be equally affected by space flight, making them more infectious pathogens. Space flight alters cellular and physiological responses in astronauts, including the immune response. However, relatively little was known about microbial changes to infectious disease risk in response to space flight. The study discovered that an important regulatory protein, Hfq, may be a key molecule responsible for the increased virulence caused by space flight. Hfq is a protein that binds to and regulates a number of regulatory RNAs - which, in turn, control gene expression. These results have important implications for human health, since Salmonella (and other gut-related bacterial pathogens) are a leading cause of food-borne illness and infectious disease, especially in the developing world. A recent experiment published in the Proceedings of the National Academy of Sciences has shown that a microbe can turn even more dangerous in space than on Earth. In that study, Salmonella was shown to become more virulent after just 83 hours of growing in space.

Research shows that the pattern of gene activity in some microbes differs in weightlessness, leading to differences in behavior. These differences could be behind a curious observation: the common food-borne pathogen salmonella becomes more virulent when grown in a form of simulated microgravity. To help keep astronauts healthy and to better understand microbial infection in general, scientists want to know exactly which genes are affected by microgravity and why weightlessness--whether real or simulated--should cause these changes. Brewer's yeast itself is not pathogenic. Nevertheless, yeast cells make a great 'model organism' for this research because they're easily handled, thoroughly studied, and their genome has been completely mapped. Furthermore, brewer's yeast shares much of its DNA with infectious species of microscopic fungi and protozoans. Also, the yeast's genome is relatively simple, which makes the results easier to analyze. Whether performed in true or simulated weightlessness, this line of research could help unravel the genetic basis of infection- a bit of knowledge that would help astronauts and land-lovers alike to live a little healthier.

The writer is Assistant Professor
Department of Microbiology
Primeasia University