Public release date: 14-May-2013 [ | E-mail | Share ]

Contact: Jim Sliwa jsliwa@asmusa.org 202-942-9297 American Society for Microbiology

Microscopic algae that live within reef-forming corals scoop up available nitrogen, store the excess in crystal form, and slowly feed it to the coral as needed, according to a study published in mBio, the online open-access journal of the American Society for Microbiology. Scientists have known for years that these symbiotic microorganisms serve up nitrogen to their coral hosts, but this new study sheds light on the dynamics of the process and reveals that the algae have the ability to store excess nitrogen, a capability that could help corals cope in their chronically low-nitrogen environment.

"It was a great surprise to find the nitrogen-rich crystals inside the algae," says corresponding author Anders Meibom of the cole Polytechnique Fdrale de Lausanne, Switzerland. "It all makes perfect sense now. The algae suck up the ammonium and nitrate like a sponge when the concentration of these molecules increases, then store this nitrogen as uric acid crystals for later use."

Like all reef-forming corals, the species they studied, Pocillopora damicornis, is actually a symbiosis of two different organisms: the coral provides protection to a species of photosynthetic algae called dinoflagellates, which, in turn, provide sugars and nitrogen to the coral host. The symbiosis allows the coral to thrive in clear, tropical waters that are naturally nutrient-poor. In many places, however, coral reefs are suffering from an excess of nutrients - pollution from sewage and fertilizers that impacts the symbiotic relationship and the health of coral in unknown ways.

To better understand these exchanges of materials and to determine how an excess of nutrients might affect the balance, the researchers exposed pieces of coral to varying concentrations of isotopically-labeled nitrogen-rich compounds. Using the facilities at the Aquarium Tropicale Porte Dore in Paris, France, the scientists applied a relatively new analytic technique called nano-scale secondary ion mass-spectrometry (NanoSIMS) to follow the path of the nitrogen. NanoSIMS enabled them to visualize and quantify the uptake, movement, and accumulation of this labeled nitrogen within the coral.

When supplied with nitrogen in the form of ammonium, nitrate or aspartic acid the dinoflagellates responded by rapidly storing the nitrogen as crystals of uric acid within its cells. But the dinoflagellates don't hang onto the nitrogen for long. Starting at about six hours after exposure, the microbes begin translocating nitrogen-rich compounds to the coral host, where the nitrogen is used in specific cellular compartments all over the surface layers of the coral.

This storage and release process helps explain how these corals get through the ups and downs of nitrogen concentrations, says Meibom. "This gives the coral-algae symbiosis a very efficient way to deal with strong fluctuations in nitrogen availability," writes Meibom. "When the nitrogen availability suddenly becomes high, the algae can take-up large amounts of nitrogen on a timescale of a few hours, store it into crystals inside the algae cells and then release this stored nitrogen for metabolic processes and growth when the nitrogen levels become normal again."

To follow up on this work, Meibom says he and his colleagues are now studying how carbon-based nutrients are taken up and distributed in the same coral-algae symbiosis.

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Link:
Microbes capture, store, and release nitrogen to feed reef-building coral

LEXINGTON, Mass.--(BUSINESS WIRE)--

T2 Biosystems, a company developing direct detection products enabling superior diagnostics, today announced details of its participation at the upcoming American Society for Microbiology General Meeting being held May 18-21, 2013, in Denver, CO. T2 Bio will provide two opportunities to learn about its core T2MR technology, as well as T2Candida, its rapid and sensitive flagship assay that is capable of identifying five Candida species directly from whole blood in approximately 3 hours with a limit of detection as low as 1 CFU/mL.

T2 Biosystems will host a symposium entitled T2MR direct detection of Candida in whole blood: rapid, species-specific identification of Candida infections. The symposium will take place on May 19, 2013, and feature distinguished speakers Peter Pappas, MD, Principal Investigator, Mycoses Study Group and Professor, University of Alabama, Birmingham and Michael Pfaller, MD, Professor Emeritus, University of Iowa. In addition, T2 Biosystems will provide demonstrations of the T2Candida diagnostic test on the T2Dx instrument throughout exhibit hall hours at booth #732.

Dr. Pfaller will present the diagnostic and therapeutic landscape of candidemia, the fourth-leading cause of hospital-acquired infections. Candidemia currently has a 40% mortality rate, largely due to the delay in diagnosis, which can take two to five days with the current gold standard of blood culture. Dr. Pappas will introduce T2Candida, T2 Bios flagship diagnostic test, as a means to rapidly and accurately identify species-specific Candida directly from whole blood in approximately three hours, which is up to 25X faster than blood culture.

Additionally, T2 Biosystems team members will conduct live demonstrations of the T2Candida test being run on its T2Dx instrument throughout exhibit hall hours. Please visit the T2 Bio booth, #732, at the ASM exhibition hall to learn more about T2MR and T2Candida.

For further information on the T2Candida Symposium, please contact mavery@macbiocom.com.

T2Candida is for research use only. Not for use in diagnostic procedures.

About Sepsis & Candidemia

Sepsis is a potentially life-threatening illness caused by the bodys severe reaction to infection by bacteria, fungi, viruses or parasites. It is one of the top 10 leading causes of death in the United States, and each hour of delayed treatment increases the mortality of these patients by 8%. Candida is a fungal pathogen known to cause sepsis, and it is associated with approximately 100,000 cases of candidemia in the U.S. annually, making it the fourth-leading cause of hospital-acquired infections. Currently, candidemia has a 40% mortality rate, which can be reduced to 11% with early identification of the specific species. Current detection methods rely on blood culture, a process that can take two to five days before identifying a Candida infection. The T2MR platform is able to detect species-specific Candida directly from whole blood without the limits experienced with optical detection technology, even at low copy numbers, and provide results in approximately three hours.

About T2 Biosystems

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