[RASMB] phage con

[Peter Edward Prevelige Jr]

Using DNA absorbance is exactly what we would do/have done if:

We knew the DNA payload/phage.
We were not certain of the particle to pfu (plaque forming unit) ratio, or wanted particles not infectious particles
We could dissociate the phage (usually we use 6 M GuHCl and some heating if necessary) to eliminate scattering
The protein to DNA ratio was <= 1 (a good approximation for spherical phage) to minimize protein contribution
We could not grow them on a host(s).

Far and away if you can grow them tittering is the easiest way to get concentration of infectious units. Lower limit (without concentration) is about 10E2-3 particles/ml and upper limit is essentially infinite.

Since phage are the most abundant organism on earth (10E7/ml seawater http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1110918/)  it is important to keep track of them.  :)

Did anybody take a look at the nanosight ( http://www.nanosight.com/)  I mentioned earlier? It is a pretty clever instrument that would seem to be perfect for this application.  Somewhat like DLS except individual particle tracking makes it more suitable for polydisperse mixtures. We were able to resolve and quantify a mixture of T=4 and T=7 capsids, detect the faction of particles with and without tails, etc. And it is sort of based on hydrodynamics so it fits the original request.

Peter



Peter E. Prevelige Jr.
Professor
Dept. of Microbiology, BBRB 416/6
Univ. of Alabama @ Birmingham
845 19th St. South
Birmingham AL. 35294-2170
Phone 205 975-5327
FAX 205 975-5479
prevelig at uab.edu<mailto:prevelig at uab.edu>
http://www.microbio.uab.edu/faculty/prevelige/prevelige-p.htm

From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On Behalf Of Ariel Lustig
Sent: Tuesday, March 09, 2010 3:33 AM
To: rasmb
Subject: [RASMB] phage con

Dear all,
I just looked in the Biophysical Chemesrty 59 paper 1996 41 - 59 E Kellenberger , E Staufer, M Haener , A Lustig, D.Karamater, >> Mechanism of  long  tail-fiber devel. of  bacteriophages.......<< we  determined  the  phage concentration  with   UV Absorption   280nm.....ariel
ariel.lustig at bluewin.ch<mailto:ariel.lustig at bluewin.ch>
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