Cell Biology 101

sue sue at murphy.prestel.co.uk
Thu Aug 21 14:17:25 EST 1997


VEIUSA at aol.com wrote:

>I will attend The American Society for Cell Biology conference in
>Washington DC in 12/97.  As a cell bio rookie, perhaps someone can
>offerinsight as to how microscopes are used in this discipline.  What are
>magnification, lighting reqt's?? Are stereo microscopes used??	if so
>how?? What % of time is spent working w/ scopes.  If times permits
>perhaps a succint application note.  ANy feedback greatly appreciated. 
>Thx in advance.  Sincerely, Mark R.
>
Well, where to start!!!  Difficult to know without knowing what you'll
be working on. 

Obviously microscopes are used all the time 'cos cells are very small!
And the standard pretty much these days is for stereomicroscopes.  In
my experience working at lens mags of x10, x40 and x100 with x10
eyepieces is normal - giving total mags of 100x, 400x and 1000x
respectively.  (x100 generally requires oil immersion, i.e that a drop
of oil of a particular refractive index is placed on top of the
coverslip- its a physicsy thing!).  
 Often you'll find add-ons like camera attachments for taking stills
of microscope images, and also video attachments for if you're working
with motile cells.
Lighting depends upon your needs, it may be normal tungsten filament
bulbs, or if you are looking at fluorescently labelled samples you may
need a mercury lamp.

Some of the good makes of microscopes for life sciences are Leitz,
Olympus and Nikon, ( N.B. they may do information boooklets) though
there are many other contenders.  Another thing is whether you use a
regular, or "inverted" mic.  If you want to look at samples growing in
culture in say a dish or flask then you need an inverted microscope,
i.e one where the objective lenses are *below* the microscope stage.

Another thing to complicate matters is the type of optics you require.
This depends on what sort of samples you'll be looking at, glass
slides or culture plastics.  Some types of optics are: ordinary bright
field, phase contrast, Nomarski, and Hoffman.  Very often you can have
a microscope with interchangeable set-ups allowing switching between
two or more types of optics, and if you're dealing with fluorescence
then switchable between different wavelength filters.  (Fluorochromes
are substances used to label cells, often by means of linkage to
specific antibodies, which emit light when irradiated with light of
different wavelengths.)   If you're having to set up from scratch then
make sure you get the most versatile system you can.

As to how often one uses the microscope?  Well if it becomes your
career then a helluva lot!   I've worked in cell biology for 12 years
now since graduating and am now slightly shortsighted!  Its an
occupational hazard apparently, the hospital optician says he sees it
all the time -especially from the departments who spend all their
working time looking down microscopes, like cytology and histology.

In the UK we have an Institute of Microscopists, I imagine there may
be the same in the States.  They might be able to provide initial
start-up info.  
 Hope this is of some use.  
Regards


--
Sue Murphy	
London, UK 		sue at murphy.prestel.co.uk	
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