[3dem] "leopard skin" ice

Fri Nov 22 12:05:24 PST 2013

I'm not sure PETA would appreciate this line of humor...

Reza Khayat, PhD
Assistant Professor
The City College of New York
Department of Chemistry, MR-1135
160 Convent Avenue
New York, NY  10031
Tel. (212) 650-6070

---- Original message ----
>Date: Fri, 22 Nov 2013 19:27:18 +0000
>From: 3dem-bounces at ncmir.ucsd.edu (on behalf of "Bowman, 
Valorie D" <vdb at purdue.edu>)
>Subject: RE: [3dem] "leopard skin" ice  
>To: "3dem at ncmir.ucsd.edu" <3dem at ncmir.ucsd.edu>
>
>Dear All,
>It can't be turtle ice.  Their scutes are usually square- 
more in line with cubic ice ;)
>
>Cheers,
>
>Valorie
>vdb at purdue.edu
>________________________________________
>From: 3dem-bounces at ncmir.ucsd.edu [3dem-
bounces at ncmir.ucsd.edu] on behalf of Dianne Taylor 
[dianne at bio.fsu.edu]
>Sent: Friday, November 22, 2013 1:42 PM
>To: Bob Grassucci; 3dem at ncmir.ucsd.edu
>Subject: Re: [3dem] "leopard skin" ice
>
>Here in Florida it has long been and will always
>be alligator, gator for short, ice.
>
>  As the many good comments suggest, there may
>well be more than one source of the problem. I
>would echo the observation that transfer of the
>cryoholder is likely the most common one. We see
>it frequently on the CM120 but not usually on the
>Titan. We see it with both manual and Vitrobot
>freezing irrespective of ethane tank age or
>fullness. Some samples seem to be more
>susceptable than others, our lipid monolayer
>samples are very prone to the "dried mud" appearance.
>
>Dianne Taylor
>At 08:53 AM 11/22/2013, Bob Grassucci wrote:
>
>>I am getting a chuckle out of the image of a
>>Leopard shaving ;)  That being said that is why
>>turtle ice may be more accurate.
>>Bob
>>On 11/21/2013 10:45 PM, Joachim Frank wrote:
>>>Hi all,
>>>just a note on the terminology:
>>>You mean leopard fur, maybe?
>>>Because the animal, shaved down to the skin, looks quite 
different for sure.
>>>
>>>--Joachim.
>>>
>>>Quoting Stefan Bohn <Stefan.Bohn at ucsf.edu>:
>>>
>>>>Hi,
>>>>
>>>>sometimes this ice was appearing, when the ethane bottle 
was nearly empty.
>>>>Sometimes, ethane bottle was full and it still appeared 
(open plunger, F20,
>>>>identical(!) sample - 20mM Hepes, 20mM NaCl, 10mM MgCl2, 
~15% glycerol) -
>>>>in those instances I attributed it to not having filled 
the nitrogen high
>>>>enough in the dewar, maybe not cooling the ethane long 
enough. Sometimes
>>>>only part of the grid showed this ice, other parts were 
normal - particles
>>>>were distributed evenly on those grids.
>>>>
>>>>But, in general, it was not reproducible. I couldn't 
correlate it to the
>>>>phase of the moon, as was suggested to me several times...
>>>>
>>>>
>>>>
>>>>Most importantly, we referred to it as "turtle-ice" (from 
Schildkroete =
>>>>plate toad).
>>>>
>>>>Hope that helps,
>>>>
>>>>Stefan.
>>>>
>>>>
>>>>
>>>>
>>>>On Thu, Nov 21, 2013 at 1:26 PM, Jacob Brink 
<jbrink at jeol.com> wrote:
>>>>
>>>>>Hi Paul and Frank,
>>>>>
>>>>>We've also seen this type of ice in Flu particle preps at 
NIBSC during the
>>>>>cryo-EM course, but we'd see it in the middle of the ice, 
away from
>>>>>particles (see below). The ethane tank had not been 
moved. So, we never
>>>>>really could attribute it to anything unless the ice 
would get really thin?
>>>>>Open air plunger (!) and imaged in a 2100-LaB6 TT.
>>>>>
>>>>>Jaap
>>>>>
>>>>>
>>>>>
>>>>>On Nov 21, 2013, at 2:36 PM, Paul Chipman 
<pchipman at ufl.edu> wrote:
>>>>>
>>>>>Hi Frank,
>>>>>
>>>>>At Purdue we called this "alligator ice" and would see it 
from time to
>>>>>time, occasionally when an ethane tank was nearing empty.  
As such we
>>>>>attributed to impurities that impeded freezing.  It could 
also be just
>>>>>something in the buffer or sample that alters the 
freezing. The recent
>>>>>image below displays this type of ice but only near the 
viral particles.
>>>>>Most of the ice was great except in areas of high 
particle concentration.
>>>>>When I told the student the name we gave this type of 
ice, I got a laugh.
>>>>>
>>>>>Go Gators! (Florida)
>>>>>
>>>>>Cheers,
>>>>>Paul
>>>>>
>>>>>
>>>>>On Wed, Nov 20, 2013 at 1:54 AM, <frankpolzer at physik.hu-
berlin.de> wrote:
>>>>>
>>>>>>Dear all,
>>>>>>
>>>>>>During the last weeks, I frequently observe what I 
believe is so-called
>>>>>>leopard skin ice in my vitrified samples (plunge frozen 
in ethane using
>>>>>>Mark IV Vitrobot).
>>>>>>
>>>>>>What again is the reason for this type of ice and how 
can this be avoided?
>>>>>>
>>>>>>Thanks for your help in advance,
>>>>>>
>>>>>>Frank
>>>>>>
>>>>>>
>>>>>>Dr. Frank Polzer
>>>>>>
>>>>>>TEM Group
>>>>>>Insitute of Physics
>>>>>>Humboldt Universität zu Berlin
>>>>>>Newtonstraße 15
>>>>>>12489 - Berlin
>>>>>>Tel.: +49 30 2093-4995 (office)
>>>>>>Tel.: +49 30 2093-7829 (TEM)
>>>>>>Fax: +49 30 2093-7886
>>>>>>
>>>>>>
>>>>>>_______________________________________________
>>>>>>3dem mailing list
>>>>>>3dem at ncmir.ucsd.edu
>>>>>>https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem<http:/
/cp.mcafee.com/d/2DRPoArhpuvKUU-
ejdTdFET73AhOtXCQQrzxO8VcsedFEIEIffzDS3qqdTAnQTQSjoygza1k52fRf
VsS8_k_BPoVyUXTAT-
LObbVEVKNRXBQn76ejouppjVqWtAklrTjVkffGhBrwqrhdECXYyMCY-
ehojd79KVIDeqR4IMjW5BphVKR4eZ1L1dnoovaAVgtHza7GCSkflbAaJMJZ0l2
OIEYTqy7uwSruud79EVsjdwLQzh0qmSkfldbFEwd4h_RmSa1EwElB0Qh6y2lLd
TdCt0VWq79>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>--
>>>>>Paul Chipman
>>>>>Assistant Director of Research
>>>>>Biochemistry and Molecular Biology
>>>>>University of Florida
>>>>>352-294-1790
>>>>>
>>>>>  
<alligator_ice.tif>___________________________________________
____
>>>>>3dem mailing list
>>>>>3dem at ncmir.ucsd.edu
>>>>>
>>>>>http://cp.mcafee.com/d/5fHCNAedEILfTssv79CXCQQrzxO8VeZPqq
dNMV4sCe76QQmkm7DNPX1Jd6XObWrWr9Ih8hB0G2x7WDYKr4vGvOVIsNstXOr_
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hojuv78I9CzATsSjDdqymo9Z2OIEYTqy7uwTwCHIcfBisEeRNB3Rjra7GBO5mU
m-
waxpmkurJh3LgrdLf6zAQsK9CMnWhEwdbra7GCBQQg6y8_WHr50QgkaOwq8zh1
aTCXCZuhzHyMKD70s
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>_______________________________________________
>>>>>3dem mailing list
>>>>>3dem at ncmir.ucsd.edu
>>>>>https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem
>>>>>
>>>>
>>>>
>>>>--
>>>>Dr. Stefan Bohn
>>>>Department of Cellular and Molecular Pharmacology
>>>>University of California
>>>>1700 4th Street, Box 2530
>>>>San Francisco, CA. 94158
>>>>
>>>>Phone: +1 (415) 476 - 2980
>>>>Fax: +1 (415) 514 - 9736
>>>
>>>
>>
>>
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>
>Dianne W. Taylor
>Associate in Research
>Institute of Molecular Biophysics
>Florida State University
>Tallahassee, FL 32306-4380
>Phone: (850) 644-4104
>E-mail:  dianne at bio.fsu.edu
>
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