Tag: Stephen Banse

Diet as a Mediator of Life-History in Ceanorhabditis elegans

Presenter: Benjamin Blue

Mentors: Patrick Phillips and Stephen Banse, Biology

Poster: 5

Major: Biochemistry 

The understanding of how diet and health interact is often informed by conventional wisdom that reduces this complex system to the idea of some foods being “bad” while others are “good.” Advances in medicine and biology have shown that health and aging are mediated by the partition of resources to these different goals. The patterning of this process is still unknown and how diets of different quality could affect such partitioning remains to be investigated. Our goal is to break down the internal calculus that informs the mediation between these different life- history outcomes using the bacteria consuming nematode C. elegans as a model. The initial experiment was a series of choice assays to determine the relative preferences C. elegans has for different types of bacterial food. Following this we performed a series of assays to measure the effects of different food sources on C. elegans life-history. The longevity of C. elegans on each food is determined using LifeSpan machines. In order to understand how C. elegans partitions its resources on different foods we compare longevity to the reproductive patterning as measured by a microfluidic egg counter. These observations will provide greater insight into the mechanisms of resource allocation and life history developments.

Evolving a Healthier Worm: Microfluidics, Pharyngeal Pumping, and Experimental Evolution in C. elegans

Presenter: Kelley Williams

Faculty Mentor: Stephen Banse, Patrick Phillips

Presentation Type: Poster 89

Primary Research Area: Science

Major: Biochemistry

Although C. elegans is a popular model for lifespan research, study of genetic and pharmacological interventions that specifically alter healthspan, the length of time an animal stays healthy, is less thorough. We therefore propose to study nematode healthspan using the decline in rhythmic activity of the feeding organ (pharynx) as a selection metric for experimental evolution. To facilitate this project, we are developing three assay platforms based on three microfluidic chips. The first two assay platforms are lower throughput, higher resolution measures of pharyngeal health, while the third is a higher-throughput assay designed for experimental evolution. The first microfluidic device, the “electropharyngeogram chip”, allows us to quantify age-related declines in pharyngeal electrical activity. This approach shows the expected changes in pump frequency and prolonged health of known longevity mutants, as well as shows novel changes in pump patterning. The second device, the “feeding chip”, is designed to provide tight temporal control of food exposure while imaging feeding animals. It also will enable measurements of grinder (chewing) and peristalsis (swallowing) efficiency. The third device, the higher-throughput “sorter chip”, was designed for separating males from females, but now allows automated and programmable selection of high performing individuals from ~2000 animals per hour as measured by ingestion rates. We will present the developmental work for all three devices and for the methods with which we use them, as well as the intellectual framework in which we are using these devices to evolve a worm that stays healthier, longer.

Life History Responses to Variation in Bacterial Food Sources in the Nematode Caenorhabditis elegans

Presenter(s): Alexander Smith

Faculty Mentor(s): Patrick Phillips & Stephen Banse

Poster 73

Session: Sciences

Diet is directly tied to the life history traits of an organism. Life history traits, such as development, reproductive capability, and lifespan, respond to changes in diet. The nematode Caenorhabditis elegans can serve as a model to demonstrate the effect of various bacterial diets on development and fecundity. Using various available natural bacteria isolates, we screened for bacterial diets that produce observable effects on the health and development of nematodes. Two bacteria species, Comamonas aquatica and Comamonas testosteroni, were observed to produce accelerated development in the growing nematodes relative to the standard laboratory diet of E. coli OP50. This prompted investigation into whether a tradeoff exists between life history traits, or whether this food source is simply a better food. We measured the number of offspring produced by organisms given a diet of Comamonas aquatica or Comamonas testosteroni and found that it is less with the number normally observed in nematodes given a diet of E. coli OP50. This demonstrates a tradeoff that is also well understood in temperature. When temperature is increase, nematode development is accelerated, and total offspring count is reduced. We found that when fed a diet of Comamonas aquatica or Comamonas testosteroni that the pattern of change relative to temperature is not consistent with nematodes on a diet of E. coli OP50. This work shows that this change in diet produces a tradeoff between development time and total offspring count, and that interactions with abiotic factors do not alleviate the tradeoff completely. Future research could show the specific nutrient composition differences in bacteria species that are responsible for the accelerated development and reduced offspring count.