Microscope looks into cells of living fish

May 16, 2012
Under green fluorescent light, cell structures, here microtubuli, can be observed in living fish embryos. Credit: NIH, KIT

Microscopes provide valuable insights in the structure and dynamics of cells, in particular when the latter remain in their natural environment. However, this is very difficult especially for higher organisms. Researchers of Karlsruhe Institute of Technology (KIT), the Max Planck Institute for Polymer Research, Mainz, and the American National Institutes of Health (NIH) have now developed a new method to visualize cell structures of an eighth of a micrometer in size in living fish larvae. It is published in the Nature Methods magazine.

"The is perfectly suited for of cells, as its larvae are completely transparent," explains Marina Mione, KIT. To visualize certain structures, these are colored mostly by methods using a fluorescent dye. Mione studied parts of the cellular skeleton of fish, the so-called microtubuli. The thread-shaped microtubuli have a length of about 100 µm and a diameter of about 20 nm, corresponding to a hundred thousandth of a human hair. "Microtubuli exist everywhere in the cell and are required for its division and motion."

In the new microscopy method, the object is not illuminated completely, but only at a certain spot with special light. Scattered light is minimized and the illuminated detail is represented sharply. A series of images taken at variable illumination is then processed by a computer. In this way, an overall image is obtained. Smart illumination even allows to adjust the depth of field, to image various depth levels, and to combine them into a three-dimensional image on the computer. "Meanwhile, it is possible to reach resolutions of 145 nm in the plane and 400 nm in-between," says Marina Mione. The images are taken within a few seconds, such that movement of the cells does not cause any unsharpness.

This video is not supported by your browser at this time.
A 3D rendering of the zebrafish tissue section shown in Figure 3. The three-dimensional volumetric rendering and video were made from the MSIM stack of two-dimensional images using Imaris software version 7.3 (Bitplane). Display brightness and contrast were adjusted to emphasize the full dynamic range of the intensities in the images. Video: Nature Methods

Based on a series of images, videos of the movement of the microtubuli are obtained. In the experiment, it was observed over a period of 60 minutes how the early stage of the fish's lateral line develops about 45 µm below the skin of the fish. Via this organ, the fish perceives movement stimuli in water. Such images of living organisms also provide valuable findings regarding the development of vertebrates on the cellular level.

The tropical zebrafish living in freshwater has several advantages as a genetic model organism. It is sufficiently small for easy cultivation and large enough to easily distinguish individual organs. It has a short generation cycle and produces many offsprings. As a vertebrate, it has a number of microbiological properties in common with human beings.

Explore further: Seeing the unseen with 'super-resolution' fluorescence microscopy

More information: The publication in Nature Methods: DOI:10.1038/nmeth.2025

Related Stories

Patchwork-like image of developing zebrafish sensory organ

June 15, 2010

This image may bring to mind a patchwork quilt, or a picture taken from a gallery of abstract paintings, but the artisan behind it is actually Mother Nature, with a little help from scientists at the European Molecular Biology ...

New microscope reveals ultrastructure of cells

November 19, 2010

German researchers at Helmholtz-Zentrum Berlin have developed a new X-ray nanotomography microscope. Using their new system, they can reveal the structures on the smallest components of mammalian cells in three dimensions.

Recommended for you

Genomes uncover life's early history

August 24, 2015

A University of Manchester scientist is part of a team which has carried out one of the biggest ever analyses of genomes on life of all forms.

Rare nautilus sighted for the first time in three decades

August 25, 2015

In early August, biologist Peter Ward returned from the South Pacific with news that he encountered an old friend, one he hadn't seen in over three decades. The University of Washington professor had seen what he considers ...

Why a mutant rice called Big Grain1 yields such big grains

August 24, 2015

(Phys.org)—Rice is one of the most important staple crops grown by humans—very possibly the most important in history. With 4.3 billion inhabitants, Asia is home to 60 percent of the world's population, so it's unsurprising ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.