A glowing zebrafish wins the 2020 Nikon Small World photography contest

While seeking answers to scientific questions, it’s worth sometimes taking a step back to appreciate the world’s exquisiteness.

For developmental biologists Daniel Castranova, Bakary Samasa and Brant Weinstein, some of that delicate beauty is inside a zebrafish. While working in Weinstein’s lab at the National Institutes of Health in Bethesda, Md., Castranova and Samasa snapped a stunning photograph of a young zebrafish, illuminating never-before-seen parts of its lymphatic system.

The photo comes from research that sought to determine whether zebrafish have lymphatic vessels inside their skulls. The lymphatic system helps clear toxins and waste from the body, and previously researchers thought only mammals had such structures close to the brain.

But zebrafish have those vessels too, Castranova and colleagues report in preliminary research posted in May at bioRxiv.org. The team used fish that had been genetically modified to have lymphatic vessels that fluoresce orange under certain conditions, with skeletons and scales that glow blue. Because fish are easier than mammals to raise and image in the lab, Castranova says, the finding could help scientists more easily study the role of the brain’s lymphatic system in neurological diseases like brain cancer or Alzheimer’s.

After taking the photo — a composite of 350 images taken with a confocal microscope — on a busy work day, “I never even looked at the picture for a couple of weeks,” Castranova says. “And then when I looked at it at some point post-data processing, I was like ‘Wow.’”

Even if it took Castranova a bit to appreciate what he had in hand, judges for the 2020 Nikon Small World photomicroscopy competition realized that it was a winner. The photo snagged first place in the 46th annual contest. The results were announced October 13.

Here are some our favorite photographs from this year’s competition.

Inside a clownfish egg

Over nine days, German photographer Daniel Knop watched an embryo grow from a striking golden yolk sac into a baby clownfish (Amphiprion percula) to produce this second place–winning photo.

The composite image, created by stacking together multiple photos that had been taken while the embryo was in motion, documents stages of the embryo’s development from left to right. The first egg shows the newly growing fish hours after fertilization, with a white cluster of extra sperm cells still on the outside of the egg. The subsequent embryos depict the fish twice on the third day of development (morning and evening), as well as the fifth and ninth days, hours before the fish hatched.

Tongue of a snail

When neurobiologist Igor Siwanowicz’s lab mate’s aquarium was taken over by freshwater snails, Siwanowicz decided to snap a photo of part of one snail’s tongue, earning him third place in the competition.

The appendage, magnified 40 times, was photographed in layers with a laser to reconstruct the tongue in three dimensions. The pieces closest to the viewer are colored hot pink; the farthest bits are blue. The tongue’s comblike projections scrape algae off of surfaces for food.

“I chose this image to show that in nature, beauty can be found in the most unexpected places, like a snail’s mouth,” says Siwanowicz, of the Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Va., and second-place winner in the 2019 contest (SN: 10/21/19).

Lab-grown hairs

Neuroscientist Karl Koehler and biochemist Jiyoon Lee, both of Boston Children’s Hospital and Harvard Medical School, captured this image of human hair follicles budding off of a cluster of lab-grown skin cells, broadly called an organoid, in a lab dish. Other types of organoids exist for various parts of the body, such as the gut and brain.  

It takes about four to five months for a skin organoid to grow in the lab. The structures develop nerves that connect specialized cells in hair follicles, much like the neural circuit system that allows us to feel touch, and could one day help develop better skin grafts. This lab-grown skin develops inside-out, Koehler says. So the surface that grows hair is inside the clump of cells, and viewers see the base of hair follicles. The team published their findings June 3 in Nature.

Majestic moss

Miroslav Žít, an amateur photographer from Prachatice in the Czech Republic, snapped this photo of a stunning moss capsule packed with spores almost ready to take flight. Capsules perch on top of stems that extend from blankets of moss.

The spores ride the wind once released, sometimes traveling long distances and staying dormant until conditions are right for growth.

Viral infection

Researchers at Brigham Young University in Provo, Utah combined more than 2,200 photos taken with a confocal microscope to create this vivid shot of a 1-centimeter-long mouse paw infected with the Chikungunya virus.

Chikungunya is a disease that can result in debilitating joint pain. Biochemists Jonard Corpuz Valdoz and Pam Van Ry teamed up with microbiologist Richard Robison to take a peek at how a mouse responds to the infection, in the hopes of shedding light on how the virus spreads in animals, including humans. The image shows that immune cells called macrophages have rushed to the paw to fight the virus.

Baby bat

While participating in an embryology course at the Marine Biological Laboratory in Woods Hole, Mass., Vanessa Chong-Morrison, a developmental biologist then at the University of Oxford, prepared this image of a Seba’s short-tailed fruit bat (Carollia perspicillata) embryo for picture day.

Chong-Morrison, now at University College London, and Dorit Hockman of the University of Cape Town in South Africa took snapshots of the developing bat’s skeleton, capturing small areas at a time. Hockman is also a developmental biologist who studies how bat hands grow into “impressive wings.” The pair then stitched together the images to produce the final photo, which was edited to show the bat’s bones in green and cartilage in orange.   

A work of amino acid art

No, this photo isn’t an abstract painting. It’s a portrait of the crystals that form after two amino acids — L-glutamine and beta-alanine — are heated in a solution made of ethanol and water. One of the compounds, L-glutamine, is a building block for proteins and ensures that the immune system can function. The other, beta-alanine, helps with muscle endurance.

Justin Zoll, a photographer based in Ithaca, N.Y., merged multiple images of crystals taken at four times their normal size into a panorama to show the crystals’ intricate details in a wider field of view. When the crystals interact with a multiple beams of polarized light, the arrangement of their molecules reflects stunning colors, he says.