phage

	PREPARATION OF BACTERIOPHAGE STOCKS ©David B. Fankhauser, Ph.D., Professor of Biology and Chemistry University of Cincinnati Clermont College, Batavia OH 45103
log phase host ready for inoculation	This page has been accessed times since 13 August 2003. 17 Feb 1993, latest revision 31 Dec 1995, 3 Jan. '97, 22 July '97, 19 July 98, 11 Aug 03	grow bacteria with aeration for optimum virus production

Bacterial viruses have proven extremely valuable in the study of the mechanisms of DNA functioning. Their short life cycle (as short as 30 minutes) combined with their large number of progeny from each cell which is lysed (up to 400 phage particles/cell) allows the production of large numbers of progeny in a short amount of time. Their growth is also an excellent model for how mammalian viruses infect and reproduce.

EQUIPMENT: (See bacterial growth)	SUPPLIES:
sterile capped 13 x 100 mm tubes 37°C hot block micropipettor with sterile tips sterile bubbler assemblies aerator with humidifier flask manifold with spaghetti tubing spectrophotometer clinical tabletop centrifuge	sensitive host bacteria (E. coli B) phage inoculant (108/mL) sterile screw capped tubes chloroform tryptone soy broth* tryptone soy agar plates* tryptone soy top agar (0.75% agar) sterile dH2O in 10 mL repipetter * Use LB medium for lambda phage

PROCEDURE:

PREVIOUS NIGHT:

1. START INITIAL HOST CULTURE: The previous day, inoculate a small volume (about 1-2 mL) of nutrient broth or tryptone soy broth with a sensitive host (E. coli B for T4 phage). Grow overnight (ON) at 37°C in hot block without aeration.

NEXT MORNING: (NOTE: Read & graph A₆₆₀ every 20 minutes during steps 2 & 3.)

2. PREPARE LOG-PHASE HOST CULTURE: The next AM, add 0.1 mL of the ON culture to about 4 mL of tryptone soy broth, and aerate at 37°C in hot block until barely turbid (A₆₆₀ = about 0.100), about 1 - 1½ hours.

3. INOCULATE WITH PHAGE: Add 0.05 mL of 10⁸/mL desired strain of phage. Aerate at 37°C until solution clears, about 1 - 2 hours. (Try ON, it might work?)

4. PURIFY PHAGE PROGENY: Spin down the bacteria in the original culture tube for 10 min in a balanced clinical tabletop centrifuge at setting 5.

Decant supernatant into screw-capped culture tube, add a few drops chloroform (~0.3 mL), shake, label with name of mutant phage, your initials and the date. Store at 4°C in the refrigerator.

5. TITER THE PHAGE CULTURE: To titer, dilute 10⁶, plate out 0.1 and 0.01 on tryptone agar using E. coli B as indicator bacteria, incubate ON at 37°C. Count plaques and calculate total phage/mL in the suspension. (For details, see protocol Titering of Phage Viruses.)

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PREVIOUS NIGHT:
	1. START INITIAL HOST CULTURE: The previous day, inoculate a small volume (about 1-2 mL) of nutrient broth or tryptone soy broth with a sensitive host (E. coli B for T4 phage). Grow overnight (ON) at 37°C in hot block without aeration.
NEXT MORNING:	(NOTE: Read & graph A₆₆₀ every 20 minutes during steps 2 & 3.)
	2. PREPARE LOG-PHASE HOST CULTURE: The next AM, add 0.1 mL of the ON culture to about 4 mL of tryptone soy broth, and aerate at 37°C in hot block until barely turbid (A₆₆₀ = about 0.100), about 1 - 1½ hours.
	3. INOCULATE WITH PHAGE: Add 0.05 mL of 10⁸/mL desired strain of phage. Aerate at 37°C until solution clears, about 1 - 2 hours. (Try ON, it might work?)
	4. PURIFY PHAGE PROGENY: Spin down the bacteria in the original culture tube for 10 min in a balanced clinical tabletop centrifuge at setting 5. Decant supernatant into screw-capped culture tube, add a few drops chloroform (~0.3 mL), shake, label with name of mutant phage, your initials and the date. Store at 4°C in the refrigerator.
	5. TITER THE PHAGE CULTURE: To titer, dilute 10⁶, plate out 0.1 and 0.01 on tryptone agar using E. coli B as indicator bacteria, incubate ON at 37°C. Count plaques and calculate total phage/mL in the suspension. (For details, see protocol Titering of Phage Viruses.)

PREPARATION OFBACTERIOPHAGE STOCKS

PREPARATION OF
BACTERIOPHAGE STOCKS