ASM 2011 Conference: New Orleans

I have arrived in lovely New Orleans! For the next couple of days, I'll be spending my time at the general meeting of the American Society for Microbiology in lovely New Orleans. I'm here at what will likely be my last ASM conference with the Slonczewski Lab from Kenyon College, where we are presenting our recent work on multi-drug efflux pumps, pH homeostasis, and fluorescence microscopy. It's really a great education for the undergraduates that my PI, Dr. Joan Slonczewski, brings along to the meeting.

The opening session was this evening and, I think, much better than the previous two years. Each of the three lectures was intriguing, accessible, and well-prepared. I was reassured that I will be heading off to graduate school in the right direction - evolution and ecology - by the fact that I found the lecture by Dr. Nicole Dubilier on symbiotic relationships between sulfur-oxidizing bacteria and marine invertebrates most enjoyable. Similarly, last year in San Diego at ASM 2010, I thought the best opening lecture was that by Dr. Nancy Moran, who spoke about her work on the relationship between endosymbiotic bacteria and leafhoppers that I wrote about last year.

The second lecture by Dr. Liping Zhao was equally fascinating. He discussed what eating well does for us physically via our microbial gut flora. This work has been in the news somewhat, but I found the thorough lecture perfect for tying together all the disparate pieces of the story. His work shows that for morbidly obese people, a change in diet from a high fat, low fiber diet to a more sensible one allows the microbiome in the gut to shift from an abundance of pathogenic organisms that can cause longterm disease to beneficial and benign organisms. For some reason, the attendees at the reception after the lectures seemed much more restrained around the over-abundance of food in the exhibit hall...

The last lecture, which I found the most difficult to follow from the detail and fast pace, was on environmental stressors that can trigger heritable changes in the organisms studied, mostly yeast. We're not talking Lamarckian giraffe's neck scale of environmentally acquired traits, but the analogy was striking.

That's all for now, but I may check in at least once more during the meeting if I'm not too exhausted in the evenings. Tomorrow we dine at the Court of Two Sisters, which sounds exciting.

Backyard biology: New greenhouse

Since I've made the decision to accept my admission offer to Ohio State University's Evolution, Ecology and Organismal Biology PhD program beginning in autumn 2011, assuring my presence in central Ohio for several more years, Adam and I decided to take advantage of a great deal on a greenhouse:

Yes, it's a rickety aluminum-frame polycarbonate panel 6' × 8' that probably won't retain very much heat in an Ohio winter, but at least I have something I've always wanted! Adam and I spent last weekend digging out the site, leveling the foundation lumber, and hauling stone to fill in the base. Once the landscaping grows in, we should have a fantastic little hide-away nook behind the greenhouse, perfect for an Adirondack chair or two.


The greenhouse will not be heated much in the winter, making it the perfect spot to overwinter hibernating Sarracenia, like those I just received from the North American Sarracenia Conservancy (NASC).

 These Sarracenia alata seedlings are propagated by members of the Grower Committee at NASC from legally-collected parent plants to maintain the genetic variety of these rare and threatened carnivorous plants. The plants I received today were from Texas, Louisiana, and Mississippi. If I do everything right, they'll grow, flower, and possibly be reintroduced in suitable locations. Many of the plants NASC acquires are from boggy habitats that are bulldozed in the name of progress or road widening. This is an excellent example of ex-situ conservation and is meant to be a complementary component to land acquisition and conservation easements (in-situ conservation).

I suppose I'm still thrilled with the idea of having my own greenhouse just steps away, but I imagine I will become less enthusiastic about it this winter when I need to trudge out there through feet of snow.

Is the common teasel carnivorous?

Dipsacus fullonum, the common teasel. An "urn" type
water storage, where dead arthropods collect.
Source: Björn Appel at Wikimedia Commons.

Dipsacus fullonum, the common teasel or Fuller's teasel, is an asterid native to Europe, Asia, and northern Africa, but is also introduced (and sometimes naturalized) in many other parts of the world, including North America. You would probably recognize it as a common weed with the distinctive comb-like inflorescence. 19th century naturalists recorded finding dead arthropods in the water-collecting cups formed by the fusion of leaves around the stem. Early suspicions for this structure focused on a protective function, since ants are unlikely to cross the water barrier to prey on the flowers.


However, the idea that the plant could be deriving some benefit from the dead insects evolved at least as early as 1877 when Francis Darwin, who, possibly influenced by his father's book, Insectivorous Plants published in 1875, submitted a paper on the topic to be published in the Proceedings of the Royal Society of London. Since then, there have been additional field observations and laboratory experimentation, especially those of Miller Christy in the 1920s, but, as F. E. Lloyd noted in his 1942 tome The Carnivorous Plants, there still was no experimental proof of carnivory. So does the common teasel derive any benefit from the prey it captures in the water urn?


The short answer is yes. Now we have experimental evidence that suggests the plants derive benefit from feeding dead dipteran larvae. Peter J. A. Shaw and Kyle Shackleton of Whitelands College, Roehampton University in London described their results in a recent article published in PLoS ONE. They found that while supplemental feedings of larvae to the plant did not increase overall above-ground biomass, both the seed biomass and seed mass-to-biomass ratio were significantly larger in plants that were fed. The authors note that the results need to be replicated, but this initial finding suggests Dipsacus fullonum meets one of the criteria to be considered a carnivorous (or paracarnivorous) plant.


Bravo to the researchers. It will certainly be interesting to see how the carnivorous plant research and enthusiast community reacts to this news. It's still uncertain how the plant derives the benefit from prey, but it's becoming more clear that Dipsacus fullonum is a candidate for status as a carnivorous plant. What exactly is a carnivorous plant, though? The exact criteria for establishing evolved carnivory and not just a happy paracarnivorous accident has been debated for years and will be the subject of a later post.

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Shaw PJ, & Shackleton K (2011). Carnivory in the Teasel Dipsacus fullonum - The Effect of Experimental Feeding on Growth and Seed Set. PloS one, 6 (3) PMID: 21445274