The Zebra Fish as a Model Organism for

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The Zebra Fish as a Model Organism for


Fig. 1:                       The zebra fish (danio rerio) is
3-day-old zebra fish
in red and green
                              very easy to breed, requiring only
fluorescence: antibody        three days to develop from an
labeled axon populations      egg into a free-swimming larva.
and GFP motor neurons
NeoLumar S 1.5x
                              As the zebra fish remains trans-
150x magnification.           parent throughout its entire de-
                              velopmental period, it is an ideal
                              organism for examinations of ver-
Specimen:                     tebrate organ development under
Prof. M. Bastmeyer,
Dr. M. Marx, Friedrich
                              the microscope. Examinations on
Schiller University           zebra fish models lead to a better
Jena, Germany.                understanding of organ develop-
Photo:
                              ment of “man the vertebrate”
Dr. M. Zölffel, Carl Zeiss.   and his diseases.

                                                                                                                             1




                              In cancer research                      For retinal diseases                     The First Stereo-
                                                                                                               microscope
                              The zebra fish has already replaced     Degenerative changes to the retina       Came from Jena
                              the well-established model organism     are genetic diseases in people that
                              – the mouse – in cancer research: the   cause photosensitive receptor cells      It all started at the Weimar Courtyard
                              mouse has a longer developmental        to die. This is one of the most com-     in Jena in 1892. Under the leadership
                              cycle and the ontogenesis stages        mon causes of blindness in humans.       of Ernst Abbe and developmental
                              are less translucent than in the        Zebra fish suffer from similar genetic   biologist Ernst Haeckel, this was
                              zebra fish. Until now, mice were used   eye diseases. The development of         the regular meeting point for
                              that develop cancer cells (e. g.        the fish eye and the activation of the   science employees from the universi-
                              leukemia) caused by genetic muta-       nerve fibers in the zebra fish’s eye     ty and the Zeiss Works. At one of
                              tions. These cells are transfected      are very similar to the human eye.       these gatherings, American zoologist
                              with GFP using molecular biology        The short development period of          Horatio S. Greenough expressed his
                              techniques. The extremely powerful      the zebra fish permits observation of    wish for a ”binocular microscope
                              SteREO Lumar.V12 fluorescence           these degenerative retinal processes     that renders true 3D images.”
                              stereo microscope enables scientists    with the SteREO Discovery.V12 and            Carl Zeiss set to work on fulfilling
                              to optimally view and research the      Lumar.V12 high-resolution stereo-        this wish and constructed the first
                              progression of the disease.             microscopes as if in slow motion,        industrially manufactured stereo-
                                                                      thus enabling better research into       microscope at the end of 1897 – the
                                                                      the cause of blindness and possible      Greenough double microscope.
                                                                      treatment methods. The eyesight of
                                                                      zebra fish larva is examined using a
                                                                      special test. The stereomicroscope
                                                                      makes it possible to examine the
                                                                      developing eyes of blind as well
                                                                      as normally sighted fish and also
                                                                      compare them to each other.




32                                                                                                                        Innovation 15, Carl Zeiss AG, 2005
Developmental Biology




                                                                                 2     3

                                                                                               Fig. 2:
                                                                                               Sketch of Greenough’s
                                                                                               idea for a binocular
                                                                                               microscope that renders
                                                                                               true 3D images.

                                                                                               Fig. 3:
                                                                                               The Greenough
                                                                                               double microscope
                                                                                               from Carl Zeiss.
                                                                                           4
                                                                                               Fig. 4:
 It had two tubes tilted towards each       marine biology: the Greenough stere-               Dissecting microscope
                                                                                               following the design
 other at a convergence angle of 14         omicroscope enabled exact research                 of Paul Mayer.
 degrees with objective lenses at the       into the lifecycle of many inverte-
 lower ends. Carl Zeiss ensured that        brates (e. g. polyps, bristle worms,               Fig. 5:
                                                                                               SteREO Lumar.V12.
 the axes on the two lenses were in         snails) for the first time. It also con-
 one plane, i.e. they actually intersect-   tributed considerably to the most im-
 ed. Porro erecting prisms were used        portant discoveries in developmental
 between the lenses and the eye-            biology and genetics of the early 20th
 pieces. These prisms ensure that im-       century (Wilhelm Roux, Hans Spe-
 ages are upright and unreversed, i. e.     mann, Thomas Hunt Morgan).
 the images can be viewed as they               Today, the SteREO Lumar. V12 is
 are in reality. This was also a demand     setting new standards for the fluores-
 from Greenough and the guarantee           cence microscope examination of
 of a true orthoscopic impression           complex issues related to develop-
 when looking through the stereo-           mental genetics in biological and
 microscope, or dissecting microscope       clinical research.                             5
 as it was called back then.
     The invention of the stereomicro-
 scope at Carl Zeiss was an essential
 contribution to the rapid upswing in
 the still young developmental and           www.zeiss.de/micro




 Innovation 15, Carl Zeiss AG, 2005                                                                                      33

				
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