Wednesday, September 11, 2013

Biomedical Research at the Volcano

Today is sunny and warm again today, with only a few thin clouds; the seas are remain calm, with 2-4 foot swells.  
Science Update: Today’s Objectives:
1) Continue with ROV Jason dive J2-730 the “Pressure Dive” – 5 days on the ocean floor to collect pressure data on a circuit of 10 Pressure Benchmarks (green dots on map at right) – in progress! (Yes, we really have one objective- to collect lots of pressure measurements on the benchmarks!)

What’s the point of studying the bacteria on a submarine volcano? PhD student, Oliver Vining thinks there is a chance he might find organisms living there that can help the medical industry develop new “drugs from the sea”. “No one has really looked at hydrothermal vents for useful bioactive compounds, but the microbes here are extremely isolated and have high biodiversity, which increases our chances of finding new and novel organisms.” The organisms he is looking for in the vents are actinomycete bacteria, which are known to produce chemicals called secondary metabolites. These chemicals can be extracted from the bacteria and tested to determine whether they have useful properties, such as the ability to kill cancer cells or pathogenic bacteria. Oliver refers to them as marine natural products and says that a large proportion of antibiotics that we commonly use are derived from secondary metabolites extracted from actinomycetes bacteria.

Syringe sampler of ROV Jason, the lever is depressed causing the spring to open the chamber as the sediment or bacterial mat sample is loaded.

Oliver’s work stems from his background in marine biology and chemistry that started at UC Santa Barbara, followed by work at Scripps in a lab focused on marine natural product discovery. He now works with Dr. Kerry McPhail in the College of Pharmacy at Oregon State University.

To collect samples of the hydrothermal vent bacteria at Axial Seamount, Oliver loads a syringe sampler (left) into a holster in the ROV Jason basket. Once in position at a vent (photo below right), Jason’s arm lifts the sampler from the basket, positions it near a vent and depresses the lever on the syringe sampler which releases a spring to open the chamber that allows sediment or bacterial mats to be collected (see video below). ROV Jason places the sampler back in the basket and on return to the surface, Oliver can preserve the sample and put it in the freezer until we return to shore and he can begin processing it in the lab at Oregon State University.

Sampling sediment and bacterial mat during ROV Jason dive J2-726 with the syringe sampler.
Oliver will culture each sample in a Petri dish with a gelatinous agar substrate on which the organisms can grow. Vent samples are swabbed across the agar and then stored in warm rooms for weeks to months during which the actinomycetes can grow. (photo below left)

Once cultured, Oliver then extracts their DNA and looks for specific genes that are known to make secondary metabolites. If these genes can be found in the bacteria, then he will look more closely at the chemicals they produce. The secondary metabolites extracted from the bacteria are put in the presence of several types of cancer or disease-causing bacteria such as E. coli, Vibrio cholerae (cholera) or Staphylococcus aureus (Staph Infection) to see if they are able to halt growth of those diseases.
Oliver cleans the syringe sampler after processing the sample for freezer storage on board R/V Thompson.
If so, Oliver uses a painstaking, iterative process called bioassay guided fractionation in which he searches for the specific chemical that can fight the cancer or bacterial diseases.

Once Oliver identifies new compounds from his vent samples, he will characterize their molecular structure to better understand how they might inhibit the growth of cancer or bacterial diseases. From this, potential pharmaceutical products or biological tools could be developed.

 On this, Oliver’s third research cruise to Axial Seamount, he has learned a lot about the geology, chemistry, and microbiology of the vents that allow a diversity of organisms to survive in a truly extreme environment.