Microbes as Models (Report 1) Prompt

Using our class microcosm experiment, you will write a research paper. Your paper must include an intro (with hypothesis), methods, results, discussion, and references section. You must include at least two references in your paper.

Each student will write a report detailing the biofilm experiment we carried out as a class. Our goal was to understand 1) if the cell density of the microcosms changes, 2) if the diversity of the colony morphology changes and 3) if mutation to a biofilm-ready morphotype is possible in the presence of 1) a biofilm disrupter and 2) being shaken or not shaken. please look over the report writing guidelines and rubric in CANVAS – in addition to the elements outlined in the report writing guidelines, make sure you include the following information:

1. Introduction: introduce important facts and background info related to your hypothesis. This could include introducing SBW25 as a model for biofilm evolution and evolution in general or describing previous findings on the three morphotypes and expected frequencies in the shaken/static microcosms (Rainey and Travisano paper). You could explain why the biofilm disrupter was tested and introduce the disrupter we used. You could also explain the potential importance of the experiment for human health. Finish this section with a hypothesis that focuses on any aspect of our main goals with this experiment.

2. Methods: in this section, you will pretend that you did the whole experiment, so definitely use Dr. Petrie’s experimental setup pdf and the video of her setting up the microcosms as your guide when writing the protocol. Note: the vials and plates were incubated for 5 days. This section should be specific enough that your experiment can be replicated (amounts, timing, etc.). This section also includes any information about statistical tests that we carried out on our data (if applicable). Write this section in paragraphs, not as a list.

3. Results: include results related to your hypothesis. This could include qualitatively describing the appearance of the vials based on photographs or describing the appearance of colony morphologies. Have a table that includes the frequency (of SM, WS, FS) and the total cfu/mL for every vial (vials 1-8; use the datasheet that your section compiled together). Make sure any average and standard deviation values that we calculated in lab are also included in this chart. No other figures are needed.

4. Discussion: see report writing guidelines.

5. References: make sure you are using at least 2 references, with in-text citations. The references should be peer-reviewed papers or books, not lecture slides or news articles. You can include the Rainey and Travisano paper as one of your references.

Answers to Common Questions:

1. Do we only write about one aspect of the experiment? Yes! This report is about one aspect of the project that was most interesting to you. That means you have a lot of leeway regarding what is included. Your hypothesis can focus on shaken/unshaken and how it affects colony morphology, or how biofilm inhibitor concentration affects cell density, or how shaken/unshaken affect cell density, etc. You get to choose.
2. Do we leave out info not related to our hypothesis? Yes! For example, if your hypothesis asks about how cell density changes in the shaken vs. unshaken treatments, you don’t need to include any info or data about the biofilm disrupter as that has nothing to do with the question you’re asking (you will want to make sure that you are comparing microcosms with similar biofilm disrupter levels, however, to ensure it isn’t a confounding variable). If your hypothesis asks about biofilm formation in the presence of different levels of biofilm disrupter, then you don’t need to discuss shaken/unshaken at all, as that is not part of your question, etc.
3. Do we need to do stats? No. Unfortunately, this isn’t a huge research project, so we don’t have much data to work with – which means that for some of you, you may be basing your results on the raw data or averaged data at the most.