Bacterial growth measurement at 600nm?

shifali chatrath via methods%40net.bio.net (by shifalich from rediffmail.com)
Sat Feb 7 05:41:37 EST 2009


Dear all!
I got to know that Bacterial cells when suspended in PBS,their O.D. should be measured at 450 nm or so. 
And I used to think, we measure O.D.at 600nm because LB is yellow and we blank the plain medium at 600nm, so we measure at 600nm.
On the other hand, i read in some discussion forum:
When measuring light scattering it is important to consider the wavelength of light used a bacterial culture. Microorganisms may contain numerous macromolecules that will absorb light, including DNA (254 nm), proteins (280 nm), cytochromes (400-500 nm), and possible cell pigments. When measuring bacteria by light scattering it is best to pick a wavelength where absorption is at a minimum and for most bacterial cultures wavelengths around 600 nm are a good choice. However, the exact wavelength chosen is species specific.

If the above statement is true then why measure at 450 or so when suspended in PBS?

Any suggestions or ideas friends?

Shifali


On Wed, 04 Feb 2009 01:02:20 +0530  wrote
>Aawara Chowdhury  wrote:
>
>>Can you share this protocol with us?
>
>Sure:
>http://www3.hi.is/~pra/SuperCompetent%20bacteria_Inoue.pdf
>
>Christian
>
>-- 
>X-no-Sig: yes
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Shifali Chatrath
Graduate Student
Protein science Lab
Dept. of Biological sciences
National University of Singapore
Singapore
+65-65161210
+65-96393449


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