Sunday, September 2, 2012

First Week in Review: Elio Schaechter, Candy, Microbial Voices, Bacteria Freezing Water, and Investigating Water Bottles...

So the first week in my Microbiology course went well, I think.  Yes, as you can see from my earlier post, I handed out some microbially-themed candy to my students. Nothing wrong with that!  Some students are a little nervous, others are already diving into the wonders of microbiology!  

As I have mentioned before, most students come to me without much background in microbiology.  How do I quickly emphasize to students the depth, breadth, applicability, and the sheer rate of change in microbiology?  I assigned a wonderful two page paper for students (and interested readers), by a remarkable man, Moselio Schaechter.  

"Elio," as he urges everyone to call him, is a past President of the American Society for Microbiology, author of many books (including a fine introductory microbiology textbook), myriad research papers, and has forgotten more microbiology than I will ever, ever know (I find it quite humbling to talk with him, even though he is always extremely polite and supportive; he simply knows so much microbiology, and how it all fits together).  Since his retirement, Elio has headed up the informative and extremely well written ASM-sponsored blog championing recent advances in microbiology, which he calls "Small Things Considered."

The paper I assigned to my students, linked here, is titled "Paradigm Shifts, Paradigm Drifts."

In this succinct and thought-provoking article, Elio presents five areas where microbiology is rapidly changing, creating changes in our current view or paradigm-set regarding the field (as with my prior post on "centrism," these preconceived notions matter a great deal to how we approach research problems!).  I strongly recommend students and interested people read this short article; there is much food for thought contained therein.

The shifting or drifting paradigms are:

  • Planetary prevalence of microbes
  • Microbes and evolution
  • Sociomicrobiology
  • Cellular microbiology
  • Microbial cell structure

I have told my students that this article describes the basic framework around which I build my microbiology course, returning to the meme of changing or shifting paradigms again and again.  Many students are unaware of these "rapidly fermenting" ideas:  that the enzymes rubisco and nitrogenase (the basis of our biosphere, to my way of thinking) are bacterial enzymes, the extent and sheer promiscuity of horizontal gene transfer, issues of quorum sensing/microbial communication in and out of biofilm communities, what bacterial pathogens have taught us about the inner workings of eukaryotic cells, and subcellular organization within bacterial and archaea.

There is an awfully lot to know, and a limited number of lectures.  Therefore,  I am glad I was able to give my students a clear, engaging road map of the journey we will be taking together, thematically.

I also encouraged my students to watch three very brief videos.  The first video describes how microbiology is starting to change the way we think about animals (and plants).  It is by the brilliant and encyclopedic expert in animal-bacterial symbioses,  Margaret McFall-Ngai.  The second video, in lab, is from an old-ish video collection from the ASM about microbiology, called "Intimate Strangers."  This video introduced my students to the very enthusiastic Karl Stetter, as well as to thermophiles.  Finally, I presented a third video, by Jon Eisen.  It was a TEDmed talk about the role that microbes play in human health (with bonus mention of "fecal transplants" and "poo-tea").  

I think it is important to try different methods in my teaching, and the use of video materials is something I hope helps many students

In lab during the past week, we spent a little time investigating those reusable water bottles many students carry, and I cannot wait to present readers with a nice illustrated atlas of what we find (which doesn't mean, by the way, that there are necessarily bad things there---we exist in a cloud of microbes, after all!).

But I did have a chance to show off a favorite student demonstration:  how Pseudomonas syringae can cause supercooled water to turn to ice nearly instantly!  The key is ice nucleation protein, which this and several other genera of bacteria use to damage plant surfaces under chilly conditions, releasing plant sap in order to provide a bacterial meal!  Subzero temperature water requires a "seed" to promote ice crystal formation; the ice nucleation protein synthesized by P. syringae provides such a template.  So I chill down some water bottles below zero (a bit tricky, that), add a drop or two of the correct bacterial culture, and...well, here is a video that demonstrates what my students enjoyed.  Even the most jaded of students is hard pressed not to "ooh" a bit.  Who can blame them?

I should add that I learned this demonstration from the great Jo Handelsman, now at Yale University, at an ASM workshop a number of years ago.  

Well, it was a great week in my microbiology course; fingers crossed for about 13 more weeks just as nice.  My students seem open to my, um, somewhat flamboyant personal style in the classroom, and seem interested and engaged!  

I have many more things to share with readers, but I will try to focus on shorter posts more frequently.  As always, I love this field of study, and I am lucky beyond words to get to present it to students each year!


  1. Great Blog Post Mark. Really Great. Thanks for sharing these tidbits, sure to help the formation of new micro courses. Ive heard that the ice nucleation experiment also shows how microbes help act as central particles to form snow. Not sure how this jives with your ice nucleation protein or not. The snow thingy would seem general where the ice protein would seem a rather specific adaptation for plant microbes. Thanks again for this lovely set of videos, paper, and opinions.

  2. Thanks, Seth! I admire the heck out of your blog, and trust me: Wolbachia really makes students think hard. Who needs science fiction?

    As for the role of bacteria in snow formation, exactly so. Here is a nice bit from Ed Yong, with a great reference.

    Thanks again! I may have some of my current students looking for Wolbachia in all the "right" places!

  3. Love the post, Doc. You've inspired me to consider a distilled version of these paradigm shifts for my non-majors bio course. I'd like to think they get a heavier dose of microbiology from me than they would from others teaching the course, but I can always improve.

    1. I should put together a guest lecture or something---"A Letter to the Microbial Masses."

    2. I would love that. We should discuss...


I am happy to hear your comments and suggestions. I hope to avoid spammage. We shall see how that works out!