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How a land predator benefits from the legacy of its marine ancestors
Prof. Dr. Georg Mayer, head of the Department of Zoology at the University of Kassel, and his colleague Dr. Alexander Bär have been studying the Australian stubby-footed species Euperipatoides rowelli since 2012. It hunts and defends itself against predators by releasing a sticky mucus that forms solid fibers within seconds when pulled and in contact with the surrounding air, thus immobilizing the victim. However, the liquid has another amazing property - it can be easily recycled: On contact with water, the solidified secretion returns to its original form.
The team previously assumed that phosphorus in the form of phosphate groups, which modify certain proteins, played a role in the special characteristics of the mucus. In a new study, the researchers have now discovered that the phosphorus is actually present in the mucus in a different form, namely as phosphonates, and is linked to sugar molecules and large fiber-forming mucus proteins. "The result surprised us, because terrestrial organisms do not usually produce phosphonates, which are mainly found in marine organisms," says Dr. Alexander Bär.
The team worked together with Dr. Alexandre Poulhazan from the Université du Québec à Montréal, among others. His analyses with mass spectrometers and nuclear magnetic resonance devices revealed that the mucus is not phosphates, as had been assumed, but rare phosphonate compounds. These give the proteins additional charges, which presumably improve their rapid assembly into strong fibers. In addition to the Australian stumpy-footed pinniped, its Caribbean relative, Euperipatoides barbadensis, was also examined. The researchers were also able to detect these phosphonate compounds in its mucus.
From the new findings, the zoologists conclude that the two species may have inherited the production mechanism of the phosphonate compound from a marine creature that lived over 500 million years ago and thus laid the foundation for the unique hunting method.
"The fact that the production of the complex phosphonate compound is very energy-intensive for land creatures and yet has been preserved over millions of years in both species suggests that the phosphonates have an evolutionary advantage over other, less energy-intensive chemical compounds. They must therefore have an essential function for the mucus, which should be investigated in more detail in the future," says Prof. Dr. Georg Mayer.
Dr. Alexander Bär recently received the prestigious Feodor Lynen Research Fellowship from the Alexander von Humboldt Foundation to continue his research at McGill University in Montreal (Canada) over the next two years.
The publication of the study entitled "Peculiar Phosphonate Modifications of Velvet Worm Slime Revealed by Advanced Nuclear Magnetic Resonance and Mass Spectrometry" was published on September 18, 2023 in the renowned "Journal of the American Chemical Society":
https://pubs.acs.org/doi/10.1021/jacs.3c06798
Contact
Prof. Dr. Georg Mayer
Institute of Biology - Head of Department
Phone +49 561 804-4805