Mutations in Bacterial Cultures
Don't Worry - Be Careful!
Treat all micro-organisms with respect - and DO NOT touch
them with ungloved hands!
Remember, mutations arise because the sequences of bases
change in the DNA. These changes can change the organism.
Could it change the bacteria to something pathogenic? Possibly.
Let's see...
Spontaneous Mutations
Occur because of environmental factors (radiation from cosmic
rays, certain chemicals) and errors in base pairing during
replication. The mutilation rate:
Some estimates are approximately 1 in every 10,000 for E.
Coli.
Seems low? Figure this:
- Let's say, the mutation rate in a given bacteria is 1
in every 10,000.
- Grow the culture to a concentration of 1,000,000,000
per milliliter.
- Grow 100 milliliters of the culture.
- How many possible mutations are there?
- Answer: about 10,000,000 (possible) mutations.
- Are any pathogenic?
- Answer: There is always a chance.
Conclusion: Be careful with all micro-organisms!
Disposing of Cultures:
ON PLATES: Put the plate in the autoclave bags in the marked
"biohazard" containers. Make sure these bags
are autoclaved regularly!
LIQUID: Put a drop or two of bleach per 100 ml in the culture
before drain disposing. Flush the drain well with water.
QUESTIONS? Call the Biosafety Officer at X2507 the the
safety office at X7233.
Revised: 8/18/2008 SF