A recent study published in Protist reports that a marine microorganism reproduces in a previously unknown way: by creating new cells inside its body, then rupturing to release them.
The bizarre process is reminiscent of the reproductive horror depicted in the movie Alien, albeit on a microscopic scale.
This microbe is part of the Labyrinthulomycetes, a group of marine microorganisms that play a key role in recycling nutrients by breaking down dead plants and animals in salty environments. Beyond their ecological importance, some species in this group are valued for producing omega-3 fatty acids like DHA, which is also found in oily fish, and carotenoids, pigments used in food coloring.
This newly discovered species also contains roughly 50% protein, adding to its potential commercial value for applications such as food supplements, infant formula, and aquaculture.
An “Alien” Reproductive Strategy
“Instead of dividing into two, as we would expect, the mature cells develop a large internal chamber in which entirely new daughter cells grow,” said Professor Peter Morris, a plant biologist at Heriot-Watt University.
“Some of those daughters already have another developing generation inside them, before they are released when the mother cell breaks open,” Morris added. “So, these microbes can be pregnant grandmothers, in the same way as some species of greenfly are born already pregnant.”
The researchers named the new species Caledochytrium aldermanii, drawing from Caledonia, the Latin name for Scotland, where it was discovered in three locations. The species name also recognizes Dr. David Alderman, whose early work culturing the microbe made the study possible.
This discovery resulted from a long-term collaboration among Heriot-Watt University, its spinout company Strameno, CEFAS Weymouth, and the Institute of Aquaculture at Stirling University.
Caught by Watching, Not Just Sequencing
Dr. Jane Polglase, who has spent nearly five decades studying Labyrinthulomycetes and co-founded Strameno with Alderman and Dr. Lydia Brown, helped document the microbe’s unusual reproduction. The team relied on traditional observation and description, an approach less common in today’s genomics-focused research.
“While lots of scientists now focus on the DNA of any creature, we’ve taken an old-fashioned approach, also observing the microbe’s behavior and describing its morphology fully,” Polglase said. “If we had not done that, we never would have captured this peculiar reproductive process on camera.” When the team finally caught it under an electron microscope, she said, “We couldn’t believe what we were seeing.”
Resourceful Marine Recyclers
Researchers found Caledochytrium in a variety of habitats, including octopus dens, on rainbow trout, and in a salt marsh along Scotland’s east coast. The researchers believe it contributes to nutrient recycling by breaking down animal and plant material.
An important part of this recycling process is the ectoplasmic net, a network of membranes the microbe creates to move around, feed, and stay buoyant. When it moves to a new surface, the microbe leaves the net behind, where marine larvae can feed on the leftover material, helping pass protein and lipids up the food chain.
What Comes Next
“Understanding how this species reproduces is key to understanding how it could be used in commercial settings, like aquaculture,” Morris said.
With this phase of research complete, the Heriot-Watt and Strameno team hopes others will continue the work. The discovery highlights how much remains to be learned about the diversity and behavior of life in the oceans.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.