Progress 10/01/08 to 09/30/10
Outputs
OUTPUTS: During the grant, we made 5 public and profession presentations on the research including: B. M. Schuster, J.A. Paulding, V.S. Cooper, and C.A. Whistler, "A symbiosis revolution: experimental evolution of a fish symbiont to a squid," a poster presentation at the 21st Annual Squid-Vibrio Symposium: Pow Wow; March 2009, Las Cruces, NM.; B. M. Schuster, V. S. Cooper, and C. A. Whistler, "Experimental evolution of fish symbiont Vibrio fischeri strain MJ11 in a squid model," a poster presentation at the Gordon Research Conference on Microbial Population Biology, July, 2009 at the Proctor Academy, NH.; B. M. Schuster, V. S. Cooper, C. A. Whistler, "Breaking the language barrier: Experimental evolution of a fish symbiont in a squid colonization model," as a poster presentation at the 6th Annual International Symbiosis Society Congress; August 2009, Madison Wisconsin.; B.M. Schuster, V.S. Cooper, and C. A. Whistler, "Breaking the language barrier: experimental evolution of non-native Vibrio fischeri in squid leads to adaptation," as a seminar presentation at Connecticut College, February 25th, New London CT.; B. M. Schuster, V.S. Cooper, C.A. Whistler "Breaking the Language Barrier: Experimental Evolution in the Vibrio fischeri-Euprymna scolopes Model," a oral presentation given at the Evolution 2010 meeting, August 2010. Portland, OR. We also published one paper on the project. PARTICIPANTS: Participants included Brian Schuster, Randi Desy, Anna Tyzik, Rachel Donner, Jessica Paulding, Johanna King, Vaughn Cooper, and Cheryl Whistler. There was important training of a graduate student, two undergraduate students and two high school students. There was also valuable professional development for the supported graduate student in giving several poster presentations, a talk at a meeting, and in writing and publishing a paper. TARGET AUDIENCES: The target audience are researchers in the fields of symbiosis, pathogen emergence, and food safety. We also have a target audience of students and the public at large for implications in evolution and food safety. PROJECT MODIFICATIONS: No major changes in course were necessary, although we added an additional evolved strain to the study (increased scope).
Impacts
We have developed and validated a novel experimental model for host adaptation by bacteria that has received considerable attention due to its utility in addressing fundamental questions in the fields of microbiology, pathogen emergence, host-microbe interactions, and evolution. Through our archived strain library, we may now answer a multitude of questions beyond the immediate scope of the project, and this resource will be available to other researchers as well. Our specific findings indicate that bacteria in the genus Vibrio have a truly remarkable ability to rapidly adapt to a novel host in a much shorter time frame than expected (in under 50 generations), primarily through changes in existing regulatory networks such that they align and coordinate cellular activities that already exist to facilitate colonization. This indicates that all the machinery for highly efficient mutualism was pre-existing even in strains that are distantly related to natural symbionts, similar as might be expected for emergent pathogens for fish and even humans. Several specific regulatory networks important in infection have now been identified (including quorum sensing, iron metabolism, and a novel and uncharacterized histidine kinase) which will be investigated further. Our findings importantly demonstrate the utility of mutualistic symbiosis models for understanding emergence of infections in general both in mode and in function. A specific impact is that it will help to identify parallel systems in pathogens that are important in agriculture (fisheries) and in food safety (Vibrio pathogens vectored by consumption of fish and shellfish) for study and possibly targeted antagonism to control disease outbreaks.
Publications
- B. M. Schuster, L. A. Perry, V. S. Cooper, C. A. Whistler, 2010. Breaking the language barrier: Experimental evolution of non-native Vibrio fischeri in squid tailors luminescence to the host. Symbiosis 51:85-96. DOI 10, 1007/s13199-010-0074-2
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: We completed the evolution of several bacterial strains through 15 squid passages and initiated strain characterization. The results of this first phase of the project were presented at three scintific meetings/conferences, and the graduate student on the project presented two seminars at the University of New Hampshire on the research. Public presentations at scientific meetings and symposia: 1. Brian Schuster, J.A. Paulding, and C.A. Whistler. A squid symbiosis solution: MJ11 Experimental Evolution. Euprymna scolopes-Vibrio fischeri Pow-Wow 2009 Symbiosis Symposium. March 13, 2009 to March 14, 2009. 2. Brian Schuster, Vaughn S. Cooper, Cheryl A. Whistler. Experimental Evolution of a Fish Symbiont, Vibrio fischeri MJ11, in a Squid Colonization Model. Gordon Research Conference: Microbial Population Biology. July 19, 2009 to July 23 2009. 3. Brian M. Schuster, Vaughn S. Cooper, Cheryl A. Whistler. Breaking the language barrier: experimental evolution of a fish symbiont in a squid colonization model. 2009 ISS Conference. One paper submitted for Brian M. Schuster, Lauren A. Perry, Vaughn S. Cooper, and Cheryl A. Whistler, 2010. Breaking the language barrier: Experimental evolution of non-symbiotic Vibrio fischeri in squid tailors luminescence to the host (in review), Symbiosis Journal PARTICIPANTS: Master's of science in Microbiology graduate student, Brian Schuster, successfully completed his first year of study on the project, presented two public seminars at UNH, and also presented at two scientific meetings. Brian is on track for completing his masters. TARGET AUDIENCES: Although there are many artificial model systems for the study of adaptive evolution, there are relatively few natural models, and even fewer mutualistic symbiosis models, therefore our audience is quite broad and encompasses scientists in theoretical and applied evolution, symbiosis, and emergent disease. Our presentations this year appropriately targeted several of these audiences and the work was received with much enthusiasm. PROJECT MODIFICATIONS: Because we made such rapid progress on our evolution, we were able to add several additional bacterial strains to the project. The opportunity for comparative work will enhance the strength of any conclusions.
Impacts
As a result of adaptation to a novel animal host, some of our bacterial strains did converge with the known symbiont for traits that we predict or know are involved in symbiosis. One of the most striking results was that two strains became dim in their light output. As light production is the key symbiosis factor, and symbiotic strains are relatively dim in comparison to fish symbionts and free living strains, this provides important validation of the evolution model. This data was met with great enthusiasm by researchers in symbiosis, and in bioluminescence at several meetings, and the findings have already been cited in a recently submitted manuscript by colleagues at University of Georgia. By further characterizing the mechanisms of reduced luminescence, this will likely provide insight into how bacteria tailor traits to specific lifestyles. Two other traits implied in but not proven to be involved in symbiosis, siderophore and biofilm capacity, were also altered in several strains. Because these traits are critical in pathogenic associations, our model may also provide insight into the role of these in symbiosis, and also as a target of adaptation. Finally, diet breadth of evolved strains also converged with the symbiont, indicating adaptation to the nutrient environment. Thus, adaptive evolution was dependent upon several disparate traits for improved symbiosis.
Publications
- Brian M. Schuster, Vaughn S. Cooper, Cheryl A. Whistler, August 2009. Breaking the language barrier: Experimental evolution of a fish symbiont in a squid colonization model. 6th Annual International Symbiosis Society Congress Abstract Book; Madison Wisconsin
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