PCR machines

[Jeremy Weinman]

In article <9210211752.AA25984 at net.bio.net>, preissj at CLVAX1.CL.MSU.EDU ("J Preiss--Seq Anal") writes:
> in response to Cheung C. Yue, re PCR Machine specs:
> 
> 	I also did some research on a PCR machine purchase.  
> 
> Requirements:
> 1.	= or < 1 degree C/sec ramp time (most important)

Do you mean this?  I would have expected that = or > 1dC/sec ramp time 
would be better.
Especialy as this statement follows:

> By the way, slow ramp times seem to radically increase undefined side
> reactions, resulting in lots of background and little product.  I have seen
> same temp conditions and samples at slow ramp speeds give only smear back-
> ground while at fast ramp times, crisp bands with no background.
> 

No flame intended: I'd just like to clear this up.

BTW:
We've just got a cycler from MJ research; Peltier driven, fully programmable 
ramp speeds (for both < and > than 1 dC/sec).
It has an in-tube thermocouple facility for even faster ramping (overshoots
the target temp in the block until the sample gets there), and the capacity 
to program touchdown cycling and increment extension times every cycle to 
allow for slowly dying polymerase.
The 16 tube variety is exceedingly cheap, but it also comes in a 40(?) sample
configuration.  I've found that it works like a charm.

(***** I've no conection with MJ Research at all *********)
 
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Dr. Jeremy Weinman				Email:	jjw at rsbs1.anu.edu.au	
Plant Microbe Interaction Group			Phone:	61 6 2495051
Research School of Biological Sciences		Fax:	61 6 2490754
Australian National University			Snail:	PO Box 475, Canberra, 
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