Zebrafish as a Model:
CHDM relies heavily on the zebrafish (Danio rerio) model in its research. It may seem odd to many to attempt to study human genetics in fish, but there are many reasons why zebrafish make an excellent tool for studying human genetics:
- As vertebrates, the functions and sequences of their genes are similar to all vertebrates, including humans. Developmental processes in zebrafish are often very similar to that of humans.
- Zebrafish embryos are completely transparent. This makes manipulations, changes, development and other processes very easy to see. It is ideal to image in this way as you can watch development unfold and see all organs, tissues and parts of the fish.
- Zebrafish have many offspring. As opposed to using other common models in research, the clutch size of a zebrafish can be 100-200 while rodents often have 10 or less babies in their litters. The offspring also grow and develop at a much faster rate than that of other vertebrates, speeding up potential for new scientific advances.
- Easy care and manipulation often make zebrafish an ideal model. Their small size and reproducible natural environment help to make the care of zebrafish less onerous than that of rodents. The more natural housing environment can also minimize the stress on the animals, making stress less likely to impact any research experiments. Additionally, many experimental manipulations being done can be done more easily than in other models because zebrafish are able to absorb chemicals and other compounds through their skin, often preventing the need for potentially painful procedures. They are also often able to tolerate higher concentrations of mutagens in their system which allows for more genetic manipulations to be researched at one time. Image credit: Fish Tank Bank
The CHDM Zebrafish Facility:
The CHDM zebrafish facility was completed in 2014. It has a state of the art filtration and recirculation system that closely monitors the fish housing, ensuring proper temperatures, salinity, purity and other factors that are essential to providing a natural and safe environment for CHDM animals. CHDM investigators have access to a dedicated space in the 2,300 square feet newly renovated Main Street zebrafish facility which has the capacity to house >20,000 adult fish. The facility is comprised of 7 rooms accessible from a continuous corridor: 1) two main rooms to house adult fish and accommodate spawning tanks, one of which is equipped with 18 photoperiod racks to maximize embryo production; 2) one small room with a standalone rack for heat-shock experiments; 3) a separate room with a state-of-the-art Techniplast aquatics pump system and Rees environmental monitoring system; 4) a food preparation and dishwashing room equipped with an IWT 650A aquatics tank washer; and 5) 680 square feet of procedure space consisting of a) a large room equipped with twelve stereoscopes and injectors for embryo injection, manipulation, and imaging; and b) a smaller room for live fluorescence microscopy, sorting and imaging.
Zebrafish injection and microscopy: Additionally, the CHDM zebrafish facility houses a very important microscope room where researchers are able to count, manipulate, inject, image and perform other research experiments with our fish. The Main Street zebrafish facility microscopy suite is equipped with microinjectors and stereoscopes to accommodate fourteen stations (four WPI PV820 Pneumatic Picopumps and ten Parker picospritzer injectors; three Nikon SMZ645, one Nikon SMZ745; three Zeiss Stemi 2000; one Stemi 2000CS teaching stereoscope; and 8 Stemi 2000C stereoscopes equipped with Axiocam 105 color cameras for bright field imaging). For fluorescence imaging, the vivarium has a Zeiss Discovery V8 stereoscope; and a Zeiss Axiozoom V16 fluorescent microscope equipped with Axiocam 503 monochromatic cameras and operated by Zen Pro software.
The CHDM microscopy suites in our Carmichael building are fully equipped for whole-mount zebrafish imaging or high magnification imaging of sections. There are three Nikon SMZ745 stereoscopes, each equipped with a Nikon digital sight color camera; three Nikon AZ100 stereoscopic microscopes with fluorescence, each equipped with a Nikon digital sight black and white camera; and for high magnification, a Nikon 90i epifluorescent microscope and a Zeiss Axioplan epifluorescent microscope, both equipped with a Nikon digital sight black and white camera controlled by Nikon Elements software. Finally, the CHDM has two Union Biometrica Vertebrate Automated Screening Technology (VAST) Bioimagers; one is connected to a Zeiss Axioscope.A1 fluorescent microscope, Axiocam 503 monochromatic camera, and operated by Zen Pro software; the other VAST is connected to a 96-well LP sampler module, a Zeiss AxioImager.M2m fluorescent microscope with autofocus capability, Axiocam 503 monochromatic camera, and is operated with Zen Pro software.
The use of animal models is an essential part of research. It is undertaken with great care to ensure that animals do not undergo any unnecessary stress, are treated humanely and handled appropriately. The CHDM as well as all Duke University laboratories comply with all government and regulatory body requirements in ensuring the proper care of its animals.