Life in subglacial Antarctic lake

Over the past year or so a number of research teams have been drilling deep into glacial ice to get at pockets of water deep below that have been in theory isolated for a very long time from the outside environment. They want to see what exactly can live in those conditions and see if these are some new life forms that we just haven't seen before. What is this environment like? Well, no sunlight penetrating down there, so no light energy driving energy production down there. Very cold too, and the pressure must be reasonably high.

One of the challenges that comes with these studies is that they have to drill a long ways down, and they have to be able to support that any life they find was from the water pocket and not contamination from above carried down by the drill.

There is a nice New York Times article about this that can be found at this link (Feb 6, 2012, Science section). They also have a great photo that shows the first view into one particular lake that I have linked into here. Looks different from what you might expect, yes? There are microbes down there and they are doing things. Keep in mind that this particular subglacial lake is 23 square miles big and ..... 5 feet deep.

We've had a number of students recently who are interested in Astrobiology. Astrobiologists are very interested in microbial life in extreme environments because it helps us understand what kinds of features of life on other planets we might expect to see if we were to find something.

On that note, I noticed that just the other day the Mars rover did a very nice drilling into the surface - will have to read more on this to see if there are plans to check for evidence of life. If so, you can bet that DNA-based approaches will be involved.

Living in sub-zero brine

Murray et al. 2012. Microbial life at −13 °C in the brine of an ice-sealed Antarctic lake. PNAS

Lake Vida is in the Antartic, how's this for a place to live:

• sits at -13 deg C
• salt concentrations 6 times that of sea water
• sits under 50-100 ft of ice
• aphotic (little or no light penetrates)
• anoxic (no oxygen)

(taken from Nature journal's website here)

As always though, microbes abound - albeit ~10-fold lower concentrations than lakes, and a lot more tiny cells that normal. Now that doesn't mean the diversity is high - in the survey they found ~32 species in 8 different phyla - but c'mon, give any microbes credit for living down there!

The researchers cored deep, viewed the cells via fluorescent staining and microscopy, and coupled that with rRNA gene sequence analysis.

Link to the original article: http://www.pnas.org/content/early/2012/11/21/1208607109

Link to more general article: http://www.nature.com/news/life-abounds-in-antarctic-lake-sealed-under-ice-1.11884

Looking for treasure trove of ancient microbes

Lake Vostok is a giant freshwater lake that is entombed beneath 2 miles of ice. It is estimated that this body of water has been sealed off for ~10 million years. Scientists have been drilling for a long time in hopes of reaching the water and to then be able to sample it.

What would they expect to find? Microbes would be the primary form. What would microbes that hadn't intermingled with other microbes in millions of years look like? That's the magic question. My guess is that there will be some really amazing things that come from this and that it will related to environmental metagenomic analysis

http://www.nytimes.com/2012/02/09/world/europe/russian-scientists-bore-into-ancient-antarctic-lake.html

http://www.huffingtonpost.com/2012/02/09/lake-vostok-microbes-unlikely-life_n_1264605.html (this article diverges quickly but for current students I like how it alludes to the extremophiles)

An interesting side note - the world's coldest recorded temperature was at Vostok - minus 128.6 degrees. They had to try to do most of this work in the "summer" when flight into the site was possible

Evidence of ancient antibiotic resistance genes in bacteria

"Researchers Find Antibiotic Resistance in Ancient DNA"

link to NYTimes article

Highlights

• researchers isolated and sequenced DNA from bacteria in 30,000 yr old permafrost
• by comparing the gene sequences to current databases they were able to identify some of the ancient genes as genes involved in antibiotic resistance

for current Micro students - so given that 30,000 years precedes human use of antibiotics (considerably I might add), why did those bacteria have antibiotic resistance genes? (let me know if you think you have an answer...you'll find out later this semester but it's an interesting one to think about in the meanwhile.)