At the workplace of a biologist [B.CI.3] who studies
the evolutionary trajectories of microorganisms

3:30 to 5:30pm, November 9, 2004


On Tuesday, 9 November 2004, I visited the workplace of Biologist B.CI.3.  She is a 6th year PhD student studying microbiology, studying how E coli exhibits antibiotic-drug resistance.  Her field sites consist of hospitals, where she is not authorized to actually take samples. The way she gets her data is “from doctors and nurses” in hospitals. 


There's a difference between wild and domesticated strains of bacteria.  She studies phenotypes/genotypes of these cultures.  In her lab, there's actually a big culture of shared work. There are a lot of shared resources, so it is easy to help someone else move a set of beakers, etc. To remember to do the shared work, she usually writes notes to herself.


For these drug-resistant bacteria, there is usually only a single nucleotide of difference.  Another difference she controls (in her cultures) is the cost of resistance, which is basically how much less efficient bacteria is at replicating (less fit it is in the Darwinian sense) when it mutates into a drug resistant strain.


She studies evolution, evolving strains.  She studies the continued evolution, which is the evolutionary trajectory of her strains.  She also studies the bottlenecks; the compensatory evolution, and the growth media.  There's a  difference between the 1/100th samples, which she will transfer to fresh media, and there are also the 1/1000 samples. 


Basically, she sees whether growth rates depend on the drug resistance and the fitness of different strains.


For transferring of cultures from flask-to-flasks, her tasks take on the order of hours. She will group flasks that are related, so that she can handle batches at a time. This rigorous process is very internalized after you've worked at it for awhile.  “Menial labor sucks.”  Menial labor includes things like counting plates (# cultures on petri dishes). To do this, she holds a counter in one hand, and marks a petri dish with the other (holding a marker). The marking and clicking of the counter is synchronized. The petri dish is viewed under a lighted display.


Her experimental setup is such that there are 20 strains of 4 treatments each. While transferring media, she periodically changes her gloves. In the lab area, she uses a Bunsen burner to “sterilize” beaker edges, and to create an updraft in her work area. She also will use ethanol 70% to clean up any spills, which she actually used several times during my visit. She uses equipment such as autoclaves which run at 121 degree Celsius at 21 lbs. per square inch.




Initial Interview on a Table






Plate Counting





Follow up on


Notebook usage




Analysis of Statistics

JMP (“Jump”) Statistical Software from


The Audio Transcript and my Interpretations

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