Our LD12 cultivation manuscript has been published

Our paper on the cultivation and genomics of the freshwater SAR11 strain LSUCC0530
has been published online in the ISME Journal (Here). The SAR11 LD12 lineage evolved to colonize freshwater ecosystems, and, like its marine cousins, occurs as one of the most
abundant freshwater bacterioplankton worldwide. Strain LSUCC0530 represents the first
cultivated representative of the LD12 clade and presented the Thrash lab with an
unprecedented opportunity to provide new insights into the important evolutionary
processes behind marine-freshwater transitions. Specifically, we demonstrated the capacity of strain LSUCC0530 to grow in salinities up to 5, provided evidence for LD12 ecotype differentiation based on temperature, and developed a hypothesis on how the loss of key genetic functions enabled the SAR11 clade to transition into fresh water. This work is only the beginning of our exploration into the SAR11 LD12 clade and its marine-freshwater transition, so be on the look out for more data soon!

If you have any questions or want to know more about LSUCC0530, please feel free to contact us! We are more than willing to answer any questions you may have.

Henson, Michael W.,  V. Celeste Lanclos, Brant C. Faircloth, and J. Cameron Thrash. (2018) Cultivation and genomics of the first freshwater SAR11 (LD12) isolate. The ISME Journal. AOP.

 

Sampling at the Calcasieu Jetties

On Monday, January 15th, I got to join Celeste on a sampling trip to Calcasieu Jetties in Cameron, Louisiana. This was my first time going on a sampling trip since joining the Thrash Lab. While it was quite a cold morning, it was still a fun time. There were some beautiful views along the way of Louisiana’s marshes.

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View of the marshes

Once we got to the sampling site, Celeste had the joy of wading out into the cold water and collecting.  At least it was a beautiful morning with the sun shining down and bright blue skies.

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The sampling site
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Celeste striking a victory pose after collecting the water sample
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Celeste filtering the sample

The purpose of this trip was to obtain a water sample for the mCURE sections of introductory biology lab. Using this sample, the students will learn high throughput cultivation protocols used in the Thrash Lab. I’m happy to have been able to help with the fieldwork and hope that the students enjoy learning about what our lab does.

Breathless: Mike’s Journey to Find Elusive Bacteria in the Oxygen-less Ocean

By Paige Jarreau. LSU biological sciences graduate student Mike Henson recently conducted field research in the great big blue! Mike works in Dr. Cameron Thrash’s lab. We asked him to tell us more about his field experience at sea below. Enjoy!

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Port is now behind us! The R/V Oceanus and crew is headed to sea. Credit: Mike Henson.

Waves stretch far into the horizon. The sun’s rays pierce the crystal clear blue water. The ocean here gives no hints about its oxygen-less waters beneath its depths. Yet, about 100 miles west of Manzanillo, Mexico in the Eastern Northern Tropical Pacific is one of largest anoxic bodies of water, or oxygen minimum zones (OMZ), in Earth’s oceans.

OMZs form when nutrient rich bottom waters from the Pacific Ocean are brought up to the surface, causing large blooms or growth explosions of photosynthetic algae. As the algae begin to die, other microscopic organisms (or backterioplankton) in the water consume oxygen to metabolize organic matter produced by the algal cells. Once you reach 100 meters below the surface, oxygen levels begin to decrease. At 300 meters, the oxygen has been completely consumed. Any organisms such as fish passing through these areas that are incapable of living without oxygen will die unless they can escape to the more oxygenated surface waters.

This may sound familiar to many Louisianans. However, unlike the hypoxia (a.k.a. the “dead zone”) that occurs seasonally in the Gulf of Mexico from nutrient pollution, this naturally occurring oxygen minimum zone is present year-round.

In the Thrash lab, we study the microbiology of northern Gulf of Mexico hypoxia. We are also collaborating with Chief Scientist Dr. Frank Stewart of the Georgia Institute of Technology, who has National Science Foundation funding to study the oxygen minimum zone in the Eastern Northern Tropical Pacific. Scientists from eight different countries, including USA, Canada, Mexico, Iceland, Denmark, Austria, Spain, and Germany, myself included, recently spent three weeks aboard the R/V Oceanus collecting water and sediment to elucidate the organisms and processes involved in forming this peculiar area of the ocean….

See the full interview with Mike and Paige Jarreau, including some epic photos, at The Pursuit LSU College of Science Blog HERE.

Thrash lab presentations at #ASMicrobe

Mike, Celeste, and Emily will all be presenting at the 2017 ASM Microbe conference in New Orleans this coming weekend. Here is the info to find them:

Saturday (6/3)
Poster Session: AES11 – Freshwater and Marine Microbiology I
Time: 12:15 PM – 2:15 PM

Cultivation and Ecology of Novel SAR11 Taxa from Coastal Louisiana Waters (#700), V. Celeste Lanclos

Metabolic and Physiological Flexibility in a Coastal Isolate from the OM252 Clade of Gammaproteobacteria (#712), Emily Nall

Sunday (6/4)
Symposium: 425 – Culturing the Unculturable in a Sequencing Age (Room 352)
Time: 2:30 PM – 5:00 PM

Fresh and Salty: Cultivating Bacteria from the Coast of Louisiana, Michael W. Henson

Cultivating members of the microbial majority

It is with great excitement that I get to post that our manuscript on cultivating members of the microbial majority using an artificial seawater medium is finally out! This manuscript represents the hard work of not just myself, but Dr. Thrash, our undergraduates (past and present), and Austen Webber. Over the last two years, I have traveled to sites along the Gulf of Mexico collecting water for cultivation experiments (> 2000 miles traveled, > 4500 well inoculated). From the sites along the coasts of Louisiana, we have cultivated organisms from the Gulf of Mexico representing many important marine clades: SAR11, SAR116, OM43, OM252, Roseobacter, and many more. While isolating these organisms is important, it is also important to isolate organisms that represent abundant taxa within your source water. We compared OTUs from community sequencing of the source water  to our  isolate sequences to demonstrate that our method frequently captured some of the most abundant organisms in the system.

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This work also represents the first instance where many of these clades were isolated from the Gulf of Mexico, and importantly, on an artificial seawater medium. While high throughput, dilution-to-extinction culturing using natural seawater has been highly successful, we hope that this new approach using artificial seawater media will help more researchers cultivate important microorganisms without the hassle of collecting large volumes of natural seawater and needing a boat.

If you have any questions, please feel free to contact us! We are more than willing to answer any questions you may have. You can check out our list of organisms isolated so far HERE!

Henson, Michael W., David M. Pitre, Jessica Lee Weckhorst, V. Celeste Lanclos, Austen T. Webber, and J. Cameron Thrash. (2016). Artificial seawater media facilitates cultivating members of the microbial majority from the Gulf of Mexico. mSphere 1(2). doi: 10.1128/mSphere.00028-16. (Undergraduate authors) Supplementary Information.

Some associated press became available on May 1st. Check out Becoming Acculturated, by Jeffrey M. Perkel.