isoamyl alcohol

Dr. Hiranya S. Roychowdhury hroychow at
Sat Mar 31 19:51:46 EST 2001

Congratulations, Gys, on your new role. I pray that you enjoy every moment
of being a "Grandfather" ... a position devoid of much responsibility other
than to spoil the object of your affection. I am afraid I have a long to
wait before my first one (seven now) would be able to elevate me to that
stature. :-)

As for the flu ... I am actually worse than I was a few days back. I
suppose this is the crest, and it will resolve henceforth. Thanks!


At 09:26 PM 3/31/01 +0200, Gys de Jongh wrote:
>""Dr. Hiranya S. Roychowdhury"" <hroychow at> wrote in message
>news: at
>> OK ... call me a heretic -- and my comments blasphemous -- but there are a
>> few "factual errors" in both the editions of "Maniatis". Amazingly, some of
>> these are carried over from the first and into the second edition.
>> I am not sure of the NaOAc - SDS observation. SDS is soluble and PDS is not
>> ... this being the principle that led to the choice of KOAc over NaOAC in
>> the classical alkaline lysis. Few Grad students (and even some beyond) ever
>> actively think about this not so subtle implication. I use KOAC for
>> everything and  sometimes I use AmmOAC. I used to use NaOAC several years
>> back (as a Grad student) and have also used NaCl (Primarily for RNA work),
>> but have never observed the phenomenon of NaOAC ppting. My Initial reaction
>> ("Eh!") was because of that.
>> Now, about the observation re: SDS-NaAc fluffy stuff: I believe that SDS
>> pptd out due to local conc. increase. If you add 10 or 20% SDS directly to
>> 2M NaOH while making a fresh bactrial lysis solution, same thing would be
>> observed. To make the solution, one should add the reagents to water, or
>> water to one of the reagents before adding the second. NaCl, having a far
>> greater dielectric point over its acetate counterpart, will have little
>> difficulty going back into solution. I doubt, therefore, that the fluffy
>> ppt is a result of EtOH or 2-propanol, per se.
>Thank you for the comments.
>You are right.
>Yesterday I tried combinations of : { NaAc , KAc , NaCl , KCl }
>with SDS {10% , 5% , 1% }
>with Ethanol { 60% , 70%}
>After 1h at -20  _all_  are  _clear_  solutions.
>Before the addition of etanol :
>Some show precipitations right after the addition of salt . All
>went back in solution at 60 degrees. Some were due to local high
>(NaAc , NaCl) . Some not : KAc and KCl gave stable prec. at rt.
>After the addition of ethanol :
>All solutions were clear.
>After cooling for 1h at -20 degrees :
>All solutions were still clear.
>> BTW, I am at a loss about the 50ng/uL DNA in 10% SDS. I have to again do
>> the "Eh!" for that. :-]
>She was a student and added TE to her DNA pellet.
>It foamed.
>I asked her what she added and she said : "like we did yesterday , from the
>little bottle with the aluminium lid". She looked very disappointed. I
gave her
>a hearty welcome to the core business of science : making more precise errors
>every day , and decided to help her. So first I tried a few things with
SDS and
>lambda DNA.
>> Kornelius' "tight precipitate" (with KCl and SDS) observation is explained
>> above (SDS v PDS). This is independent of the conc. of either of the
>> I am suffering from flu presently ...
>I became a grandfather presently :)
>I hope you are well again.
Dr. Hiranya Sankar Roychowdhury
College Asst. Prof.
Molecular Biology,
Dept. of Chemistry & Biochemistry	
Box 30001 - 3MLS
New Mexico State University
Las Cruces, NM 88003

Lab: (505) 646 4722
Office: (505) 646 8256
hroychow at


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