Biology Kit Experiments with Bacteria

[Jeff Edney]

How do we obtain pure cultures from the three bacteria species combinations?  The background information in the procedure for lab VII-2 discusses how differential media can be used to obtain only a specific culture that you want to grow, but in the procedure to actually do this in the lab manual, we are left on our own to figure out how to pick the 3 different bacteria to then produce pure cultures.  In fact, the manual could easily give us the information on how to do this but the procedure instead relies on guess work and mostly luck and not science.

Help!

[Robert Bruce Thompson]

Hi, Jeff

I'm not entirely sure what's going on. Your messages to me keep ending
up in my spam folder which I don't check very often. I've added an
exception for your email address that should ensure they end up in my
inbox. Also strangely, I responded to this and the second email when you
posted the questions to Google Groups. I'll forward copies of those
emails after I send this.

Robert Bruce Thompson
thom...@thehomescientist.com

[Jeff]

I'm having trouble seeing threads.  Did you post a reply to my question in this thread or only by email?  Sorry for my confusion.

[Jeff]

I found this on a web site:

http://faculty.ccbcmd.edu/~gkaiser/puzzles/Lab%203/LAB%203%20-%20OBTAINING%20PURE%20CULTURES%20FROM%20A%20MIXED%20POPULATION.html

[The Home Scientist]

The three species in the bacteria culture can be identified by their morphology and by using Gram staining.

o Bacillus subtilis (bacillus, Gram+)
o Micrococcus luteus (coccus, Gram+)
o Rhodospirillum rubrum (spirillum, Gram-)

[Jeff]

Found a great page.  You can click on the 3 different types of bacteria we receive and see what the colonies look like.  This was what I was looked for all along.

http://academic.pgcc.edu/~kroberts/web/colony/colony.htm

On Friday, February 12, 2016 at 9:27:03 AM UTC-6, Jeff wrote:

[Jeff]

Is it true that the Rubrum  bacteria require light (assume sunlight) to grow?  See this:  https://media.vwr.com/emdocs/docs/scied/Bacteria_&_Fungi.pdf

On Friday, February 12, 2016 at 9:27:03 AM UTC-6, Jeff wrote:

[Jeff]

Here is the best detailed web site I could find of very detailed info.

https://www.fishersci.com/content/dam/fishersci/en_US/documents/programs/education/brochures-and-catalogs/brochures/carolina-biological-techniques-studying-bacteria-fungi-brochure.pdf

On Friday, February 12, 2016 at 9:27:03 AM UTC-6, Jeff wrote:

[Jeff]

Question.  I ended up buying 2 culture tubes.  I also transferred one of the 2 tubes to test tubes containing only salt water (distilled water and NaCl).  Do these cultures live on after I open them, or should I use the bacteria that I transferred to the salt water test tubes for further experiments?  Which is the most stable?  Does one or two of the 3 types of bacteria tend to die quickly after opening the purchased 3 strain bacteria cultures in a test tube?

On Friday, February 12, 2016 at 9:27:03 AM UTC-6, Jeff wrote: