Georgia Tech researchers found many types of bacteria, include E.coli, in the middle to upper regions of the troposphere. (Photo: USDA)

Scientists have discovered a considerable number of living microorganisms, including bacteria, in the middle to upper regions of the troposphere, the region of our atmosphere that’s about seven to 20 kilometers above the Earth’s surface.

Researchers from the Georgia Institute of Technology said their findings might help other scientists learn more about the role microorganisms play in forming ice that may impact weather and climate.

Health and medical experts studying the transmission of disease could also benefit by gaining new insight into long-distance transport of bacteria.

Conditions in the troposphere cannot support most other forms of life without the aid of special equipment. Temperatures there can drop to as low as -55° C and the air pressure and density are considerably lower than on earth.

Microorganisms, such as bacteria, are plentiful and can be found everywhere on the Earth and in the sea.

These hardy little forms of life not only survive but actually thrive in some of the harshest conditions known to man. They live within other forms of life, such as the human body; in the soil and the air surrounding us; in scalding hot springs; the great depths of the ocean; and inside rocks deep within the Earth’s crust.

A view outside the window of a DC-8 aircraft as air samples are gathered for a NASA study. Georgia Tech scientists found living microorganisms in the samples. (Photo: NASA)

The microorganisms  documented by Georgia Tech scientists were gathered from air samples recovered as part of NASA’s 2010 Genesis and Rapid Intensification Processes (GRIP) program, which studies low- and high-altitude air masses associated with tropical storms.

NASA gathered the air samples from aboard a DC-8 aircraft that flew over both land and ocean, including the Caribbean Sea and portions of the Atlantic Ocean during and after two major tropical hurricanes in 2010, Earl and Karl.

Attaching a special filter system developed by the Georgia Tech team to the aircraft’s outside air sampling probes, researchers were able to collect numerous particles, including the microorganisms.

Once the air samples were taken, the filters were removed from the aircraft and sent to researchers for examination.

Rather than resorting to conventional cell-culture techniques to make their analysis, the researchers instead used genomic techniques, including polymerase chain reaction (PCR) – a biochemical technology used in molecular biology that magnifies a piece of DNA, allowing scientists to generate millions of copies of the DNA sequence, as well as gene sequencing to spot and estimate the quantities of microorganisms contained within the air samples.

The researchers found more bacteria than fungi among the microorganisms.

“We did not expect to find so many microorganisms in the troposphere, which is considered a difficult environment for life,” said one of the study’s authors, Kostas Konstantinidis, an assistant professor at Georgia Tech. “There seems to be quite a diversity of species, but not all bacteria make it into the upper troposphere.”

Terry Lathem, a graduate student in Georgia Tech’s School of Earth and Atmospheric Sciences, aboard a NASA DC-8 aircraft while gathering samples of microorganisms in the atmosphere. (NASA)

The living bacterial cells found made up about 20 percent of the total particles detected within the size range of 0.25 to 1 microns in diameter.

Air samples taken over the ocean were found to contain mostly marine bacteria, while primarily terrestrial bacteria was found in samples taken above land.

The researchers also found that hurricanes had a major impact on the distribution and dynamics of microorganism populations.

Kostas Konstantinidis joins us for this weekend’s radio edition of Science World.  He’ll tell us how these findings could help advance research in climatology and medicine.

Check out the right column for scheduled air-times or listen now to the interview below.

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DNA structure (Image: Michael Ströck via Wikimedia Commons)

Prevailing wisdom holds that every cell in the body contains identical DNA.

But Yale researchers say they examined skin stem cells and found a number of genetic variations in a variety of skin tissue.

The study, published in Nature, could have profound implications for genetic screening.

“We found that humans are made up of a mosaic of cells with different genomes,” said lead author Flora Vaccarino, M.D., from the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.”

It’s been long believed that all of our cells have the very same DNA sequence.

Other scientists conducting similar genetic research have theorized the DNA sequence of a cell could be modified during the cell’s development – when DNA is copied from a mother cell to a daughter cell.  These many changes to a cell’s original DNA, they say, could affect an entire group of genes.

While it’s difficult for scientists to actually test these theories, the Yale researchers say they have been able to do so for their new study.

To reach their findings, the research team used whole genome sequencing – a genome is a complete set of hereditary information – to study induced pluripotent stem cells (iPS), which are genetically engineered stem cells developed from a mature-differentiated cell.

The team grew cells taken from the inner upper arms of people from two families. For two years, the researchers examined their genetically engineered iPS cell lines, compared them to the original skin cells, and noted any differences between each cell’s DNA.

The team also conducted further experiments to see what might have caused the differences to occur.

While the research in the project outlined in this recent study was limited to finding variations in DNA sequencing within skin cells, the Yale team is continuing its studies to see if these same DNA variations can be found in developing brain cells of animals as well as humans.

(Photo: Michael Howard via Flickr/Creative Commons)

Exactly where man’s best friend came from remains a mystery.

Thousands of years of cross-breeding have made it difficult for scientists to trace the ancient genetic roots of today’s dogs.

Still, British researchers gave it a try. They recently compared genetic data from 1,375 modern-day dogs, from 35 different breeds, to global archeological records of dog remains.

Although, other genetic studies suggest dogs descended from the grey wolf, the researchers found modern dog breeds, genetically speaking, have little in common with their ancient ancestors.

Dogs were the first animals domesticated by man about 15,000 years ago. However, we really didn’t start keeping them as pets until about 2,000 years ago.  Even so, until fairly recently, most dogs were kept and used to perform specific jobs.

Although some dog breeds – such as the Akita, Afghan Hound and the Chinese Shar-Pei – have been classified as ancient by canine experts, they’re no closer to the first domesticated dogs than any other modern breeds.  This, according to the study, is again due to cross-breeding through the years.

Other aspects affecting the dog’s genetic diversity include human movement and migration.  Major worldwide events, such as the two world wars, also impacted the dog population, the researchers said.

Breeds like the Saluki appear genetically different because they were geographically isolated and were not part of the 19th century efforts to blend lineages to create most of the breeds we keep as pets today. (Photo: Keith Dobney)

Lead author Greger Larson, an evolutionary biologist in Durham University’s Department of Archaeology, said, “Ironically, the ubiquity of dogs combined with their deep history has obscured their origins and made it difficult for us to know how dogs became man’s best friend.  All dogs have undergone significant amounts of cross-breeding to the point that we have not yet been able to trace all the way back to their very first ancestors.”

Previous studies of breeds such Basenjis, Salukis and Dingoes indicated they had different genetic signatures, which provided evidence of an ancient heritage.

But the researchers say their new study shows the unique genetic signatures in these dogs were not necessarily due to being directly descended from ancient dogs, but merely appeared to be genetically different because they were geographically isolated and were not part of the 19th Century kennel clubs which blended various lineages in order to create most of the breeds we’re familiar with today.

As DNA sequencing becomes faster and cheaper, the scientists are hopeful more research will provide further insight into the evolution and domestication of our canine friends.