When you are using phase contrast, the vacuoles will usually look much
brighter and more sharp-edged than nuclei.  My preferred way of
recognizing nuclei is to look for the peripheral nucleolus.  It will
appear as several phase-dense bodies pressed against the inner boundary of
the nuclear envelope.  It is easier to pick out the nucleolus by focusing
up and down through the nucleus than if you stay in one focal plane.  The
nucleolus can be harder to pick out with bright field and DIC because
there is not as big a contrast difference as there is with phase.
Anything you can do to flatten the cells out will help.  Also, since the
nuclei are much smaller than those in most amoebozoans, it can really help
if you are able to use oil immersion for its better resolution. - Fred
Spiegel

Frederick W. Spiegel
Professor

Department of Biological Sciences
SCEN 601, 850 W. Dickson
1 University of Arkansas
Fayetteville, AR 72701 USA

Phone: 1 479 575 4248
Lab: FERR 214, Phone: 1 479 575 7393
Fax: 1 479 575 4010





On 4/7/14 8:32 AM, "Carl Franck" <[log in to unmask]> wrote:

>Dear Colleagues, Can you please say if in your experience there are
>any large organelles (vacuoles?) that we might encounter in axenic
>Dicty (in our case AX4) that are so large that they might be mistaken
>for nuclei (thanks to the Dicty base list's thoughtful advice, we are
>hopefully close to doing satisfactory fluorescent nuclear imaging, but
>this would be very helpful to know at this stage of our work using
>bright field and phase contrast microscopy). I tried to check the
>literature (e.g. first image of Plate 1 of  Richard Kessin's
>monograph) but am still unsure of the answer. Thanks for reading and
>any advice you might have, best spring wishes in this hemisphere, Carl
>
>-- 
>Carl Franck
>Associate Professor, Physics
>Clark Hall E18, 525
>Cornell University
>lab phones: 607-255-5215 and  255-3562 (long ring for messages)
>home phone: 257-6969 (until 10PM)
>please note that I frequently use Google Voice to send calls, but do
>not receive them on that number