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LB (Luria Bertani) broth and medium

 

LB broth

 

(1)   10g Tryptone

(2)   5 g yeast Extract

(3)   10g NaCl

(4)   1ml of 1M NaOH (1M = 0.4g/10ml)

 

Add water to 1L and autoclave.

 

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LB Medium

 

(1)   10g Tryptone

(2)   5 g yeast Extract

(3)   10g NaCl

(4)   1ml of 1M NaOH (1M = 0.4g/10ml)

(5)   15g Agar

 

Add water to 1L and autoclave.

 

 

If you need to make LB-antibiotic medium (e.g LB/Kana or LB/Amp):

 

* Don't add antibiotic to the broth or medium prior to autoclaving. Autoclave will damage the antibiotic. Instead do the following:

 

(1)   Prepare LB broth or LB medium as above and autoclave

 

(2)   Wait till it cool up (reaches 55-50C), then add the desired filter-sterilized antibiotic as follows:

 

(a)    For Ampicillin: add 1ml of stock to 1L LB medium (where 1000X stock is 100mgAmp/ml of water). Thus, the final (i.e. working) concentration is 100g/ml.

 

(b)   For Kanamycin: prepare stock as 500mg/ml water. Take 100l in 1L medium to get working concentration of 50g/ml.

 

 

(c)    For Chloroamphenicol: prepare stock as: 34mg/ml ethanol. Take 1ml of this stock in 1L medium to get final conc of 34g/ml

 

 

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