Microbial Population Biology

To reiterate what I assigned in today’s class:

For this week’s blog, please find and discuss a scientific report on the potential advantages of sexual recombination.  Please provide a working hyperlink to your article or web resource.

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Scientists Uncover Vast Microbial Diversity of Carnivorous Pitcher Plant

The microbial ecosystem inside the carnivorous pitcher plant is vastly more diverse than previously thought according to research published in the March 2010 issue of the journal Applied and Environmental Microbiology.

Researchers from LouisianaStateUniversity used genomic fingerprinting technology to assess the bacterial diversity inside leaves of Sarracenia alata, commonly known as the pitcher plant. A pitcher plant is a carnivorous plant that lives in nitrogen poor soil augmenting the inadequate nitrogen by trapping and digesting insects. It has tubular shaped leaves that contain a liquid that is used for digestion. Over the past 35 years studying these plants using traditional culture-based methods, scientists have only identified 20 distinct bacteria in the pitcher.

“The microbial richness associated with the pitcher fluid from Sarracenia alata is high, with more than 1,000 phylogroups identified across at least seven phyla and over 50 families,” say the researchers, who studied 10 plants in a Louisiana wildlife management area for 5 months during the spring and summer of 2009.

The researchers noted as well that approximately a third of all the bacteria were unidentifiable. They also observed that not only were the bacterial populations distinctly different from nearby soil samples, they started out different in each plant but over time they became more similar to one another.

“These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction,” say the researchers.

(M.M. Koopman, D.M. Fuselier, S. Hird, B.C. Carstens. 2010. The carnivorous pale pitcher plant harbors diverse, distinct, and time-dependent bacterial communities. Applied and Environmental Microbiology, 76. 6: 1851-1860.)
http://aem.asm.org/cgi/content/full/76/6/1851

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Hi all, a quick note to say that I’ve updated the syllabus to reflect our best-laid plans for the remainder of the semester. We’ll begin with our leftovers prior to break (immigration and diversification) and then turn to an appropriate spring topic, recombination.

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A reminder that your first exam (worth 15%) is this Thursday in class.  It will be open-book, -blog, -notes but will not be collaborative.

To reiterate what I said in class, please prepare by reviewing the central concepts and points from each lecture and from each assigned reading.  Since it is open-book the exam will require application and synthesis and not just regurgitation of facts.  I encourage you to spend some time with the materials so that you will be efficient with them during the exam.

You will need to review and interpret some of the literature that I reviewed in class, ie the papers that I reviewed in lecture but that we did not discuss in recitation. You will also have to draw figures that illustrate concepts or findings, since a picture is worth 1,000 words.

UPDATE:  Here is a link: MLST lab to our MLST laboratory; these will be returned for your reference in the exam.

If you wish to receive any credit for blogs that you have been assigned but not yet completed, Friday 3/12 is your deadline for partial credit. To review, you should have posted on:

1) Sulfolobus and Baas-Becking
2) What the bacterial species concept means to you, esp. in light of MLST
3) Any topic in microbiology for which the species concept matters, to you,
4) Whether experimental evolution (microevolution in the laboratory) can shed light on macroevolutionary phenomena (like the Cambrian explosion)
5) At least 1 comment/post in response to one of your colleagues’ posts

best,

VC

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As we discussed in class, please comment this week on your blog whether experimental evolution of microbes (eg Travisano et al) can shed realistic light on macroevolutionary phenomena (eg the Cambrian explosion).

As always, be creative. Enjoy!

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Now that you’ve read and understood the Whitaker et al paper (link here) on Sulfolobus biogeography, please address the following for Tuesday 2/7:
1) How do their results relate to (or complicate) the Baas-Becking hypothesis (everything is everywhere, the environment selects)?
2) What else do you wish that they (or you) would do with this project, and why? What new questions do you have?

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Hi gang, check your feeds, live –>

(seriously, please let me know if your blog isn’t loading)

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You should all have received an email that you have your own new blog. Start playing with it and please write a post, stating why you’re taking the course, and/or what interests you, and/or what you want to be when you grow up. If you go to http://edublogs.org you’ll find lots of help on moving into your new online home.

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