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Very basic questions regarding Micrococcus on inorganic nitrogen agar - (Oct/15/2008 )

Hello everybody, :-)

I'm a beginning microbiology student, describing the set up of an experiment, and I'm hoping to find information regarding this:

The experiment is supposed to prove that Micrococcus roseus does not grow on an inorganic nitrogen agar plate.

As my positive control, I chose Micrococcus luteus.
As my negative control, I picked Micrococcus varians.

However, I cannot find any further information regarding this experiment.

I tried googling a few basic questions but was unsuccessful. I'd be really grateful if someone could answer them:

How is an inorganic nitrogen agar plate made? (Is nitrogen added to regular nutrient agar? If so, how much is added?)

How would I incubate an inorganic nitrogen agar plate with M. roseus, M. luteus, and M. varians? (Temperature and time?)

Many thanks for your help in advance.

Jessie

-Jessie86-

QUOTE (Jessie86 @ Oct 16 2008, 11:30 AM)
Hello everybody, :-)

I'm a beginning microbiology student, describing the set up of an experiment, and I'm hoping to find information regarding this:

The experiment is supposed to prove that Micrococcus roseus does not grow on an inorganic nitrogen agar plate.

As my positive control, I chose Micrococcus luteus.
As my negative control, I picked Micrococcus varians.

However, I cannot find any further information regarding this experiment.

I tried googling a few basic questions but was unsuccessful. I'd be really grateful if someone could answer them:

How is an inorganic nitrogen agar plate made? (Is nitrogen added to regular nutrient agar? If so, how much is added?)

How would I incubate an inorganic nitrogen agar plate with M. roseus, M. luteus, and M. varians? (Temperature and time?)

Many thanks for your help in advance.

Jessie


Regular nutrient agar contains peptone and meat extracts i.e. complex components containing the essential elements needed by the bug. You'd need to add an inorganic nitrogen source (NH4Cl perhaps) into what we call minimal salt agar. You'd have C source as well as other necessary elements (S & P) for growth.

I'd culture it as I would a normal plate since it's not fussy with its oxygen requirements. As for temperature, Micrococcus should be able to grow at 25 - 30C - partly being a bacterium from soil and also a mesophile.

I hope others will add to these..

Mean time, hope this will aid you in a way or the other (theoretically)

http://aem.asm.org/cgi/reprint/65/6/2577

-Dreamchaser-

Thank you very much. This helped a lot! :-)

I have one more question:

From what I understand, inorganic nitrogen agar functions as a selective medium in my experiment (one species will be able to grow, while the other two will not)...

Some media such as EMB select for Gram-negative bacteria, while others such as MSA select for salt tolerance...

What does inorganic nitrogen agar select for? Does it select for nitrogen tolerance?

Again, many thanks in advance.

Jessie

-Jessie86-