Ultrasonic Homogenizer question....

Dr. Hiranya S. Roychowdhury hroychow at nmsu.edu
Tue May 11 10:16:51 EST 2004

Very empirical.
The output needed usually varies from one tissue/cell type to another. A rule 
of thumb that I have applied to sonication of tissues and cells is to deliver 
several 5 to 8 sec pulses, while holding the temp around 0 C (ice water).  

How a protein would fare through sonication is up to the protein itself.  Mst 
proteins survive well through the process.  Established protyocols even allow 
for 10-15 sec pulses at full power.  Again, since soniactors come with 
different wattages, it is best to empirically determine the conditions to be 
used, unless one has an already established protocol for the same or a similar 
tissue/cell/organism.  There are several posted and/or reported.  

As for DNA shearing, one just needs to do it till the viscosity is gone.

Quoting OK <khanoy at teranews.com>:

> I was wondering if anyone can please describe briefly the functions of the
> parameters such as pulse, frequency %output etc. that appear on a typical
> ultrasonic homogenizers apparatus and how they can be altered to get a good
> protein extract from a tissue sample.
> More questions...
> Does too much sonication damage the proteins too?
> How can DNA in a tissue lysate be sheared to decrease the viscosity of the
> lysate?
> Thanks

Hiranya S. Roychowdhury, Ph.D.
Coll. Asst. Professor,
Molecular Biology,
Dept. of Chemistry & Biochemistry
Rm# 336, Chemistry Bldg.; MSC 3MLS
New Mexico State University
Las Cruces, NM 88003

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