Scientists use a variety of standard research organisms, including fruit flies and mice, to study the evolutionary development (evo-devo) of animal lineages. Expanding the diversity of these research organisms advances our understanding of life and advances biomedicine and environmental conservation.

In a recently published study Frontiers in Evolutionary Developmental BiologyScientists from the Marine Biological Laboratory (MBL) in Woods Elven and the Stazione Zoologica Anton Dohrn (SZS) in Naples, Italy, have introduced a species of sea cucumber. Holothuria tubulosa as a new species. evo-devo study of the organism.

Advantages of using echinoderm

Holothuria tubulosa, Found in the Mediterranean and the eastern part of the Atlantic Ocean, sea urchins belong to the echinoderm group that includes starfish and sand dollars. Some species of echinoderms have been used in developmental research for more than a century due to their economic efficiency, high fertility, diverse larvae and, more recently, their suitability for genetic studies.

“Echinoderms are the invertebrates genetically closest to humans, which means we share many of our genes. If we understand how these genes work in echinoderms, we know how they work in humans as well,” said MBL scientist Margherita Perillo, who led the study.

“Sea cucumbers also have attributes and special skills, such as feeding on sediments that clean the ocean floor and the ability to fully regenerate their entire bodies, which could be useful for conservation and biomedicine,” he added.

Protocol for obtaining embryonic cultures

The first step of creation H. tubulosa As a research organism, a protocol had to be developed for the efficient production of embryonic cultures under laboratory conditions. Current methods, including mimicking the animal’s natural reproductive cycle and ensuring the release of all of the animal’s organs through evisceration (a behavior sea cucumbers often display under threat), have been difficult, ineffective, or both.

To overcome this, a team led by SZS’s Rossella Annunziata and Perillo developed a non-invasive technique to repeatedly collect small numbers of gametes (sperm and eggs) over a long period of time. Microsurgery involves making a small incision near the sea cucumber’s reproductive organs, allowing you to obtain the testicles or ovaries. The incision heals quickly, allowing researchers to collect animals every few days.

Because the eggs obtained with this technique are immature and cannot be fertilized, the researchers then expose the collected ovaries to thioredoxin-2 peptide, a synthetic peptide known to work in other species, making them receptive to sperm. They then grow the fertilized egg in culture, where it reaches the metamorphosis stage in about eight weeks.

Perillo explains: “Our protocol eliminates the main bottleneck through which H. tubulosa “It has not been used as a research organism, and it opens the door for more scientists to use it.”

Achievements and future prospects

The team used high-resolution microscopy combined with immunohistochemistry to document larval development, focusing on their unique structures. Their detailed description will form the basis for future studies aimed at using genetic manipulations for functional analysis of H. pylori development. tubulosa .

In addition, they provided an example of how scientists can use echinoderm larvae to study the diversity of anatomical structures in closely related organisms. In this case, they used serotonin immunostaining to show how the location of serotonin neurons differs between echinoderm species. Why and how this diversity occurs is an open question in the biology of evolutionary development.

“The sea cucumber is an amazing animal, and the better we understand it, the more valuable it becomes as a research organism,” Perillo said. “I now plan to develop genetic tools to further characterize this as a new comparative model in evo-devo. This collaboration also laid the foundation for the creation of new species of sea cucumbers in MBL.”