Riddle me this!

Slide1I picked up one of the two remaining unknowns from the mystery rack, after all BIO230 students chose their unknowns. I have conducted a series of biochemical tests on unknown #3, but will not reveal its identity quite yet. Here is an opportunity for you to test our your Dichotomous Key, and to earn a bonus point.

Each test was inoculated for 24 hours at 37 °C, and various reagents were added to cultures where appropriate. The appearance of each test at this point is presented below:

IND -> no reaction

MR -> red color

VP -> yellow color

CIT -> green color

PHE -> green color

LYS -> brown color

GEL -> liquid

SUL -> black color

URE -> pink color

You may infer results to Carbohydrate Fermentation tests by the following:

MacConkey’s Agar -> white colonies

Triple Sugar Iron Agar -> red slant, yellow butt, no cracking of agar

Here is the Bonus opportunity; using your dichotomous key and the above results, determine what Unknown number 3 is. To preserve the fun, email me your answer! Note that this special Bonus opportunity is only available until the end of Spring Break on Monday evening April 1st at 6PM.
UPDATE! Unknown #3 was Proteus mirabilis. The combination of the urea and indole tests would have been a good tipoff. Thanks to all who played!

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About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on March 26, 2013, in Bonus!, Lab. Bookmark the permalink. Comments Off on Riddle me this!.

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