Vibrio Fischeri Wrinkly Spreader vs. Smooth Morph Growth So Far

So far this summer, I’ve been able to collect data on V. fischeri growth over a salinity gradient spanning most of the range between zero percent sodium chloride and nine percent sodium chloride with intervals of 0.2 percent sodium chloride. I currently have data on zero, one, two, three, all the way through nine percent and I’m working on finishing the intervals within that range.

The data collected so far suggests that the wrinkly spreader strains of V. fischeri grow to lesser cell densities (measured by OD600 via spectrophotometer) than the ancestral smooth morph strains. This could suggest that the adaptive radiation that produces the wrinkly spreader morphology also affects the response to osmotic pressure of V. fischeri. However, it is more likely that this difference is the result of wrinkly spreader strains growing more slowly in liquid shaking cultures than the smooth morph ancestors. In this case, further experimentation may be necessary to establish a relationship between the adaptive radiation that occurs in standing culture and stress physiology.

An example of another type of experiment that I may attempt in the future would be the generation of a survivability or death curve. Instead of looking at the strains’ ability to grow in different salinities, we could look at their ability to survive in environments with different salinities. This could be accomplished by inoculating artificial seawater of various salinities with V. fischeri cells and measuring OD600 after twenty-four hours in a shaking incubator. We would then calculate the percentage of the original inoculate that survived in the artificial seawater. Essentially the same protocol would be followed with the exception of using artificial seawater instead of LBS growth media.