How a Charles River scientist’s images and movies are helping to inform our understanding of vascular development
Daniel Castranova is an aquatic research specialist who uses cameras and microscopes to view the living cells and tissues of zebrafish. The Charles River scientist is an insourced contractor with the Weinstein Lab, part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the US National Institutes of Health.
Brant Weinstein’s laboratory, one of the leading research groups studying vascular development in the zebrafish, created many of the most commonly used tools and methods for studying vessels in the fish, including a confocal microangiography method, an atlas of the anatomy of the developing zebrafish vasculature, numerous vascular-specific transgenic lines, and methods for high resolution in vivo imaging of zebrafish blood vessels.
Studying vascular development in most vertebrates is a challenge because we can’t image, with a great deal of specificity, what is occurring inside their blood vessels. Zebrafish are an exception. Every blood vessel in a living embryo can be seen using nothing more than a dissecting microscope. The ability to collect thousands of progeny from a single pair of adult zebrafish also makes it easy to map mutations and clone genes to less than .1 centimorgan resolution.
Dan was part of a team from the Weinstein laboratory who created an image that was selected as one of the winners of the 2017 BioArt contest sponsored by the Federation of American Societies for Experimental Biology that also included winners from Yale University and Tufts University. Eureka Editor Regina McEnery recently spoke with Castranova about how he merges his twin passions of science and photography.
How did you find your way to the NIH?
DC: I was getting ready to defend my Master’s thesis at the University of Maryland. A colleague of mine who graduated from the same program told me about the position. That was in 2003. When I started, my main duties involved managing the fish for the lab and managing mutagenesis screens, but I took an interest in imaging and now I’m also co-managing our image core, including training, maintenance and image acquisition assistance on three confocal microscopes, a lightsheet microscope and several fluorescent stereo microscopes.
How is a confocal microscope different from other microscopes?
DC: In a traditional fluorescent microscope, the specimen is flooded evenly with specific colors of light exciting fluorescent proteins or dyes. So when you look through the view finder, all of the light that is emitted from the sample reaches your eyes. A confocal microscope uses a laser to illuminate the sample and a pinhole between the sample and detector, which blocks out all of that out-of-focus light. Because only light that is very close to the focal plane can be detected, an optical section is created. These optical sections can be combined to create a 3D volume.
Can you describe some of the work your lab is doing with zebrafish?
DC: Our lab focuses on blood vessels, where they come from and how they grow. We also look at lymphatic vessels, which intermingle with blood vessels. We conduct basic science but our studies allows us to look at the bigger picture. We can think about the broader picture, like the mechanisms that cause blood vessels to grow and how this can have implications on tumor development. Our group published a nice paper last year in the journal Development on the larval lymphatic system of zebrafish that may shed some light on a poorly understood area: how lymphatic networks assemble. The image (shown at right and at top) is an 18-day-old double transgenic zebrafish strain. The blood vessels are shown in red and lymphatic vessels shown in green. The image was taken on a Zeiss 880 Confocal microscope.
Tell us a bit about the BioArt winner shown below?
DC: This image shows that Fluorescent Granular Perithelial cells (FGPs, in green) are closely associated with the blood vessels (red) that surround an adult zebrafish’s brain. The FGPs are novel type of cell found in both zebrafish and mammals, and researchers suspect that they play a key role in maintaining the blood–brain barrier and clearing toxic substances from the brain.
How was it shot?
CD: We used a Caliber ID RS-G4 Ribbon scanning confocal with a Nikon 25X 1.1NA W objective. The strength of this system is its ability to quickly collect high resolution images over a large area.
Do you have a favorite piece of art that you created?
DC: The work I am most excited about right now is a video showing the first 22 hours of development of a zebrafish embryo. The video (shown below) shows zebrafish development from a single cell through about 22 hours post fertilization. The fish is transgenic Tg(fli1a-eGFP y1) expressing green fluorescent protein in blood vessels.
Finally, what advice would you give to aspiring creators of bioart?
DC: I feel like I got lucky ending up in a zebrafish lab. The zebrafish is a great model for development and disease, but its optical clarity and the availability of transgenic lines make it great for producing bioart. That being said, I think we can find beauty in any scientific discipline if we are looking for it.
Interested in learning more? Charles River Insourcing Solutions℠ can streamline research by delivering operational and cost efficiencies through the strategic insourcing of research services from discovery through safety assessment. Additionally, through a collaboration with the Fish Vet Group (FVG), the world’s leading dedicated aquaculture health monitoring provider, Charles River offers the most comprehensive zebrafish services to proactively monitor the health of zebrafish colonies.