Science Buddies: "Ask an Expert"

The question I have been studying is, Do bacteria remember the conditions they were grown on and does this affect how they respond when innoculated onto the same agar type as compared to a new agar type? I have not found any real concrete evidence except one strain of my switched bacteria (I am using Bacillus cereus) changed from a clear, light yellow color to a darker and more opaque yellow. What does this mean? And how can I show the data I have collected so far? It is mostly colony counts, size, and growth rate.

Also, I am connecting all of this to food poisoning and cross-contamination of food. Any thoughts on this?

Hi Togo123,

This is a really unique idea for a science project. Bacteria can grow on a wide variety of food sources and environmental conditions and they may utilize different biochemical pathways when grown under different conditions. The color of the colonies can vary depending on the type of medium they are grown on, but B. cereus is usually what to cream colored and the colony color usually darkens with age. What media have you been growing the B. cereus on and have you seen any differences other than the clear light yellow/dark opaque yellow color?

Have you done background reading on B. cereus food poisoning? Here is information on Bacillus cereus and includes a description of the toxins that can cause food poisoning. B. cereus food poisoning is associated with rice dishes that are held above room temperature for a prolonged period of time; this organism can grow at a temperature of up to 140 degrees F (60 degrees Celsius),

http://textbookofbacteriology.net/B.cereus.html

Epigenetics of bacteria is a new and fascinating are of investigation, but I could not find any specific information on B. cereus. DNA methylation has been found to control DNA-protein interactions that can play a role in virulence and based on research on other pathogenic bacteria; it is certainly possible that there is a heritable epigenetic mechanism for B. cereus food poisoning. Here is a review paper on the general topic.

http://mmbr.asm.org/content/70/3/830.full

This topic is not my primary area of expertise, but I certainly try to provide additional advice if you will explain more about your project. Please let me know more about your colony counts, size, and growth rate.

Donna Hardy

Hello!
Yes, I have done lots of research on epigenetics and Bacillus cereus. I used Nutrient Agar and Tryptic Soy Agar. I was trying to think of a way to organize my data chart. Also, is it appropriate to just cut and paste articles and information about epigenetics, info on Bacillus cereus, etc. straight onto my science display board? If I can do this, do I include the link under the article or just in the bibliography? Thank you!

Hi,

Since this is not a common topic for a science fair project, it will be helpful if you can do anything possible to make your results more visual so the science fair judges will "see" what happened. Can you photograph examples of different colony types to illustrate the descriptions? It sounds like you have data on colony counts, size, and growth rate as well as the observations on color and opacity so it might make sense to organize the data into 4 separate charts, so the reader can focus on one set of data at a time. Do you have enough data to do statistical analysis? Here's information from the Science Buddies website on data analysis and graphs.

https://www.sciencebuddies.org/science- ... ysis.shtml

It is much better to summarize your references and select the specific information that is pertinent to your project. You should also cite the source of your information. If you use a direct quote, you should use quotation marks.

It will be helpful for this project to include a brief abstract under the title The abstract includes the purpose, problem procedure, results and conclusion all condensed into a couple of sentences.

https://www.sciencebuddies.org/science- ... ract.shtml

Donna Hardy