Many disciplines – such as developmental biology, molecular biology, embryology, plant sciences and neurobiology – work with model organisms that often need special handling or preparation before further examinations such as genetic studies.
Model organisms can be bacteria, fungi, plants or animals. Ideally, model organisms should exhibit certain characteristics:
- Share many genes with humans
- Small size and easy to grow in the lab
- Visible congenital traits
- Sequenced genome available
- Easy genetic manipulation
- Genetically tractable
- Short generation times and life cycle
Examples of common model organisms:
C. elegans (a nematode), zebrafish Danio rerio and the fruit fly Drosophila melanogaster are widely used, respectively, in worm labs, zebrafish labs and fly facilities. These model organisms need to be routinely sorted, picked, counted, manipulated, dissected, imaged and monitored during their development stages (e.g. egg, embryo, larva …). Stereo or dissecting microscopes are indispensable tools for these tasks.
Microscope Requirements
There are two types of stereo microscopes – Greenough and Common Main Objective (CMO) – each with its own special characteristics. The CMO-type provides certain advantages over the Greenough-type, particularly when it comes to illumination, fluorescence capabilities, digital image documentation and ergonomics. Greenough stereo microscopes, however, are more compact, highly integrated and economical in price.
Scientists and technicians can be supported in their daily routines by a 3D stereoscopic view combined with a large free-working distance and ergonomic features. These microscopes are perfect for mechanical manipulation, sorting, and general sample preparation. Stereo or zoom microscopes are also used preferentially for fluorescence screening of modified genotypes (for example, through CRISPR/Cas9 mediated mutations) in transgenic studies using markers such as the green (GFP) or red (RFP) fluorescent protein. Combining a large field of view with high resolution will speed up this process significantly.
Dissecting microscopes are also widespread in neuroscience – say, when dealing with larger vertebrate animals such as rats, which often serve as a source of primary cell cultures.
Application Examples
Recommended Microscope Systems for Sample Preparation:
ZEISS Stemi 305
This compact Greenough stereo microscope features a 5:1 zoom for use in educational and biological labs. You can observe samples such as plants, insects or other small animals in three dimensions for identification, dissection, preparation and documentation. Stemi 305 is very easy to use since everything is integrated: long-life LED illumination for various contrasts and digital documentation, too.
ZEISS Stemi 508
Apochromatic optics let this compact Greenough microscope acquire images of outstanding contrast and color accuracy. Its mechanics are designed for heavy workloads, making it optimally-suitable for routine lab work. The large object field ensures you will always keep an overview of your sample or model organism while the 8:1 zoom allows quick examination of details. Stemi 508 offers various transmitted light contrasts to optimize visualization – ideal for manipulating, sorting, dissecting and documenting your zebrafish, nematode or fly. Meanwhile, the low viewing angle of 35° means you will stay relaxed even after hours of work.
Greenough Stereo Microscope with 8:1 Zoom
ZEISS SteREO Discovery.V8
This modular CMO-type stereo microscope offers an 8:1 zoom range with highest resolution. With its rock-solid stand and superb stereoscopic impression SteREO Discovery.V8 is an ideal tool for sample preparation, even at high magnifications. Up to three different fluorescence channels can be observed using powerful, maintenance-free fluorescence LEDs. It excels for fluorescence screening in transgenic studies. Opt for the intermediate tube combined with the ergotube for best-in-class ergonomy. Digital documentation produces precise measurements, z-stacking and extended depth of focus.
Brilliant Entry into the Class of Sophisticated Stereomicroscopes
ZEISS Axio Zoom.V16
This is the perfect tool for fluorescence screening applications in your developmental or molecular biology lab. Axio Zoom.V16 offers a detail-rich, clear stereoscopic image. The zoom range of 16x allows you to observe complete model organisms and visualize small details with ease – say, when you are preparing fly brains. Most importantly, the very high aperture will give you superior brightness of fluorescence signals in large object fields. This unique combination saves time in the fluorescence screening process of your zebrafish, C. elegans or Drosophila samples while allowing you to acquire high quality, detail-rich images. Combine it with Apotome.2 for brilliant optical sections.