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ASU spaceflight research pioneer receives top NASA science award

August 04, 2011

Microbiologist uses spaceflight platform to usher in new era of innovative research

Cheryl Nickerson, a microbiologist at Arizona State University’s Biodesign Institute received the Exceptional Scientific Achievement Medal – NASA’s most prestigious commendation for outstanding contributions to science.
"It is a distinct honor and privilege that my biological research in support of the U.S. Space Program has been acknowledged by NASA in such a prestigious format," said Nickerson. "It is the goal and passion of my team to use the microgravity environment of spaceflight as an innovative research platform to unveil novel cellular and molecular mechanisms directly relevant to disease progression that cannot be observed here on Earth. I am excited with the potential of this work to both mitigate the risk of infectious disease to the crew during future exploration missions, as well as for development of novel strategies to diagnose, treat and prevent infectious disease for the general public."

It has been an exciting and tumultuous few weeks for both NASA and Nickerson. On July 8, her most recent experiment – designed to study the effects of spaceflight on a new type of vaccine – rocketed toward the International Space Station aboard the space shuttle Atlantis, on its emotional final journey.

"It is always an unbelievably exhilarating experience to watch your science launch on a Shuttle, but this final mission of the Shuttle program evoked a particularly wide range of emotions," said Nickerson. "While we will profoundly miss this fleet of incredible vehicles and gratefully acknowledge their amazing scientific accomplishments, we also realize that Shuttle has paved the way for a series of next generation spaceflight vehicles. These vehicles, including commercial craft, will continue Shuttle’s legacy of carrying experiments into space, thereby providing scientists with routine, reliable and affordable access to the unique microgravity research platform."

Nickerson has been using spaceflight or spaceflight analogues to study microbial behavior since 1998. In an audacious series of experiments, she was able to validate her early hunches about the responses of certain microorganisms to conditions of reduced gravity. Initially intrigued by the well-known fact that astronauts are immunocompromised during spaceflight and could thus be more susceptible to infection, Nickerson pondered the
effects of reduced gravity  on the disease-causing capacity or virulence of human pathogens.

"The findings from our initial spaceflight experiments were surprising and revealed that the food-borne pathogen, Salmonella, became more virulent when cultured in the microgravity environment of spaceflight," said Nickerson. "Equally surprising, we found that spaceflight globally altered the gene expression of Salmonella in key ways that were not observed during culture on Earth, leading  to the identification of a master switch that regulates this response.

We also found that spaceflight altered the virulence characteristics of other bacterial pathogens, and that they used the same master switch to regulate their responses as did Salmonella."

Nickerson also proposed a mechanism for the profound microbial changes observed under low gravity – a reduction in a physical force known as fluid shear, exerted by liquids as they flow over cell surfaces. Not only was reduced fluid shear a plausible trigger for the changes in virulence and accompanying gene expression Nickerson observed, it
 provided a tantalizing clue about how pathogens might switch their virulence on and off during the normal infection
process on Earth. Microorganisms, including pathogens, are known to encounter regions of low fluid shear during their migrations through the body during the infection process, including in the gut, respiratory passages, and the urogenital tract.

Importantly, these spaceflight-based discoveries are directly applicable to the general public, and the information from these studies is being used to develop novel therapeutics against Salmonella and other infectious agents to reduce human mordibity and mortality on Earth.

The Exceptional Scientific Achievement Medal is awarded to both government and non-government individuals for accomplishments that are “far above others in quality or excellence – a rare, outstanding, clearly superior achievement.”

Nickerson’s path-breaking investigations using the unique platform of spaceflight clearly fit NASA’s stringent criteria for this important award.

According to Duane L. Pierson, Chief Microbiologist at NASA’s Johnson Space Center: “Dr. Cheryl Nickerson has pioneered ground and spaceflight research on microbial pathogens resulting in the most significant advancements to our understanding of microorganisms in the microgravity environment of space.  Her contributions have provided invaluable knowledge of the delicate balance of host-microbe interactions that ultimately determines the difference
between health and disease.”

Mark Uhran, Assistant Associate Administrator of the International Space Station is similarly enthusiastic about Nickerson’s contributions and the intense commitment she brings to her research: “Without any doubt, Dr. Cheryl Nickerson has consistently been among our top scientific performers in the field of  space-based microgravity research. Her impeccable attention to scientific quality and keen appreciation for the benefits of applications-oriented
research distinguishes her clearly in the field.”

Although the last mission of Atlantis on July 18th marked the space shuttle’s swan song, Nickerson says that work will
continue at the International Space Station due to a newly signed Space Act Agreement between NASA and ASU's Biodesign Institute.

"Our work to date merely builds the foundation from which a tremendous amount of research still needs to be accomplished. I am confident that  spaceflight platforms, such as the International Space Station National Laboratory and commercial spacecraft, will provide exciting, ground-breaking discoveries in a variety of biomedical fields that
will translationally advance human health and quality of life for many years to come."