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<div class="">This looks like leopard ice to me (attached, 2D projection and tomogram (suraface and inside view) around ~ 0.5 nm pixel site). </div>
<div class="">This type of artifact could grow overtime on the surface of cryo-lamella prepared by FIB milling when the dual-beam stage temperature is compromised.</div>
<div class="">If you take tilt the stage or take a tilt series, you might see the ice grows on the surface of the samples (not inside). The shape and heterogeneity vary also could change overtime.</div>
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REIKA WATANABE CASTILLON Ph.D.<br class="">
Elizabeth Villa laboratory<br class="">
Department of Molecular Biology<br class="">
University of California San Diego 9500 Gilman Dr.<br class="">
Tata hall room 5100<br class="">
La Jolla, CA 92093<br class="">
M/C 0335<br class="">
Office and Laboratory: 858-822-4038<br class="">
<a href="mailto:recastillon@ucsd.edu" class="">E-mail: recastillon@ucsd.edu</a></div>
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<div class="">On Nov 20, 2019, at 6:15 AM, Reinhard Rachel <<a href="mailto:Reinhard.Rachel@biologie.uni-regensburg.de" class="">Reinhard.Rachel@biologie.uni-regensburg.de</a>> wrote:</div>
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<blockquote type="cite" class="">20.11.2019 at 14:54:<br class="">
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Jacopo,<br class="">
<br class="">
Assuming these are pictures of a frozen specimen, I would assume the spots <br class="">
are artifacts of likely radiation damage, especially if they bear no <br class="">
resemblance to your protein prepared by negative staining. The spots also <br class="">
vary in size. Does that resemble your protein? If so, then you have a very <br class="">
heterogeneous sample.<br class="">
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<br class="">
I can understand the comments by David (Belnap) ... <br class="">
and take the opportunity to make (more) people aware of Theresa's and Arne's pictures and remarks on sample homo-/heterogeneity and background, in JSB 203 (Sept 2018) 242-246<br class="">
Theresa Gewering, D. Januliene, et al .... "Know your detergent ...."<br class="">
I was for long not aware of this Techn.Note, but only had similar experiences ...
<br class="">
kind regards - Reinhard<br class="">
<br class="">
-- <br class="">
Prof. Dr. Reinhard Rachel<br class="">
University of Regensburg<br class="">
Centre for EM / Anatomy<br class="">
Faculty of Biology & Preclin. Med.<br class="">
Universitaetsstrasse 31<br class="">
D-93053 Regensburg - Germany<br class="">
tel +49 941 943 -2837, -1720<br class="">
mail <a href="mailto:reinhard.rachel@biologie.uni-regensburg.de" class="">reinhard.rachel@biologie.uni-regensburg.de</a><br class="">
office: VKL 3.1.29 <br class="">
member of the IFSM board<br class="">
<br class="">
Next microscopy conferences:<br class="">
- EMC2020 in Kopenhagen, 23.-28.8. 2020 (European conference)<br class="">
- MC2021 in Vienna (D-A-CH conference)<br class="">
- IMC20 in Busan, South Korea: Sept 25-30, 2022<br class="">
- next Microbiol. conferences: VAAM 8.-11.03. 2020 Leipzig<br class="">
<br class="">
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_______________________________________________<br class="">
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