[RASMB] determination of phage particle concentration

Peter Edward Prevelige Jr prevelig at uab.edu
Thu Mar 4 04:37:30 PST 2010


Hi Sabine

If you care about total particles and know the approximate mol. weight of the DNA then absorbance is good.

EM counting with known standard

If you want to know infectious particles you'll have to titer 

Have you seen the Nanosight? It does single particle scattering on very low concentrations of virus. Tracks individual particles and reports back number and size through Stokes-Einstein. We just had a demo and it seemed to give accurate results on several different icoshedral phages that we knew the concentration of. 

Be glad to help out but more details would make things clearer. 

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
http://www.microbio.uab.edu/faculty/prevelige/prevelige-p.htm

-----Original Message-----
From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On Behalf Of Timothy Dafforn
Sent: Thursday, March 04, 2010 5:18 AM
To: kaltofen at uni-potsdam.de; rasmb at server1.bbri.org
Cc: dandres at uni-potsdam.de
Subject: Re: [RASMB] determination of phage particle concentration

depending which phage it is you can get a good idea of concentration from the OD280 
for instance for M13 the major protein, by far, is pVIII. the sequence for this protein is available so you can calculate an extinction coefficient. If you then assume 2500 copies per phage particle then you can get a concentration.. (its a bit approximate).
If it is M13, I have a txt doc with details..
Cheers
tim
________________________________________
From: rasmb-bounces at rasmb.bbri.org [rasmb-bounces at rasmb.bbri.org] On Behalf Of kaltofen at uni-potsdam.de [kaltofen at uni-potsdam.de]
Sent: 04 March 2010 10:57
To: rasmb at server1.bbri.org
Cc: dandres at uni-potsdam.de
Subject: [RASMB] determination of phage particle concentration

Dear all,

we are trying to obtain the concentration of bacteriophages in a
solution, concentration meaning the number of particles per ml. The
solution is supposed to be monodisperse and the MW is (roughly) known
but could be determined exactly. Is the any idea of how to do this
with a hydrodynamic method (staining is difficult to compare between
phage mutants and counting infected cells is tedious). I`ve got the
"feeling" that one could use the number-averaged MW, but maybe this is
totally wrong.

Thank you for any hints, literature is also welcome.

Cheers,

Sabine




Sabine Kaltofen
PhD student

Universität Potsdam
Department of Physical Biochemistry
Institute of Biochemistry and Biology
Karl-Liebknecht-Str. 24-25, Haus 25, Raum B/0.05
D-14476 Potsdam-Golm
Telefon: +49-(331)-977-5245
Email: kaltofen at uni-potsdam.de



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