Russian Scientists Have Studied Marine Worm with Unique Spermatozoa
Russian scientists at A.V. Zhirmunsky National Scientific Centre of Marine Biology, HSE University, and Moscow State University have studied Phoronis embryolabi, a rare species of marine invertebrate found in the waters of the Sea of Japan. This species is notable for its unique reproductive system, which includes the development of larvae within the parent’s body and an unusual sperm structure. The study's findings contribute to our understanding of the evolutionary adaptations of marine organisms to extreme conditions. The study has been published in Zoologischer Anzeiger.
Phoronis embryolabi is a small marine worm that is viviparous, meaning it gives birth to live young, with larvae developing inside the parent’s body. This is an important adaptation for Phoronis embryolabi, which lives as a commensal organism—a type of symbiotic relationship where the commensal benefits while the host remains unaffected—in the holes of burrowing shrimp. It has been discovered that the reproductive process in this species involves the formation of spermatozoa with an unusual structure.
Spermatozoa are filamentous cells capable of moving within the confined spaces of the body. They develop in vasoperitoneal tissue (VPT) that surrounds blood vessels. 'This structure enables spermatozoa to move efficiently through narrow spaces filled with cells and embryos,' according to Elena Temereva, Professor of the Joint Department with RAS Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, HSE Faculty of Biology and Biotechnology.
Unlike other phoronid species, whose spermatozoa are V-shaped, Phoronis embryolabi’s spermatozoa maintain an elongated shape throughout all stages of maturity. The flagellum, essential for movement, is closely aligned with the cell body, which aids in movement through the narrow spaces of the body cavity. This is important, because the numerous embryos and other cells developing inside the body create additional challenges for sperm movement.
Sperm cells in Phoronis embryolabi, known as introsperm, possess unique adaptations typical of species with internal fertilisation. To reach the eggs, they must navigate through dense layers of cells and squeeze in the narrow spaces within the body. The researchers found that these spermatozoa are equipped with a collar around the base of the flagellum, which, along with undulating movements, enables them to move through the densely packed inner spaces of the animal. This movement resembles that of certain single-cell parasites, such as trypanosomes, which use similar mechanisms to move through a viscous medium.
For comparison, in other phoronid species, such as Phoronis pallida and Phoronopsis harmeri, introsperm are V-shaped cells composed of two parts: one part is the flagellum, while the other contains the nucleus and mitochondria. In Phoronis embryolabi, all components of the sperm are closely interconnected, which enhances their ability to move efficiently through narrow spaces. In addition, their spermatozoa are shorter than those of other species, which may also be an adaptation to the habitat conditions.
The study of spermatogenesis and sperm structure in Phoronis embryolabi provides valuable insights into how organisms adapt to extreme conditions. This information helps deepen our understanding of the evolution of reproductive biology in marine invertebrates and the factors that have influenced the development of complex reproductive strategies.
The unique adaptations of spermatozoa in Phoronis embryolabi are a crucial component of this species' survival strategy. The ability to move through narrow spaces and fertilise eggs in a body filled with embryos and other cells is an example of a successful evolutionary adaptation.
The research was carried out with support from the Russian Science Foundation.
See also:
Z-Flipons: How Specific DNA Regions Help Regulate Gene Function
Researchers at HSE University and InsideOutBio have applied machine learning to identify the location and functions of mirror-twisted DNA structures, known as Z-flipons, in human and mouse genomes. The scientists discovered which Z-DNA regions were conserved in both species throughout evolution and demonstrated for the first time that Z-DNA accelerates the process of creating RNA copies of genes. The findings will contribute to the development of new treatments for genetic diseases. The study has been published in Scientific Reports.
HSE Researchers Develop Python Library for Analysing Eye Movements
A research team at HSE University has developed EyeFeatures, a Python library for analysing and modelling eye movement data. This tool is designed to simplify the work of scientists and developers by enabling them to efficiently process complex data and create predictive models.
Scientists Identify Fifteen Key Motives Driving Human Behaviour
Researchers at HSE University and the London School of Hygiene and Tropical Medicine have identified 15 key motives that drive human behaviour. By analysing people's views, preferences, and actions through an evolutionary lens, they demonstrated how these motives intertwine to shape habits and interpersonal relationships. The findings have been published in Personality and Individual Differences.
HSE Neurolinguists Create Russian Adaptation of Classic Verbal Memory Test
Researchers at the HSE Centre for Language and Brain and Psychiatric Hospital No. 1 Named after N.A. Alexeev have developed a Russian-language adaptation of the Rey Auditory Verbal Learning Test. This classic neuropsychological test evaluates various aspects of auditory verbal memory in adults and is widely used in both clinical diagnostics and research. The study findings have been published in The Clinical Neuropsychologist.
Tickling the Nerves: Why Crime Content is Popular
Consumers of content about serial killers watch and read it to experience intense emotions that are often lacking in everyday life and to understand the reasons that drive people to commit crimes. However, such content does not contribute to increased aggression. These conclusions were drawn by sociologists from HSE University. The results of their study have been published in Crime, Media, Culture: An International Journal.
HSE Researchers Prove the Existence of Nash Equilibrium for a New Class of Problems in Game Theory
Researchers at HSE University's St Petersburg School of Economics and Management have been exploring methods for the efficient allocation of resources in systems involving multiple players. The scientists have proven the existence of strategies for optimal decision-making in competition for limited, discrete resources in four different cases. The developed mathematical model can be applied in various fields, ranging from education and medicine to managing networks and computing power. The paper has been published in Games and Economic Behaviour.
Researchers at HSE Centre for Language and Brain Reveal Key Factors Determining Language Recovery in Patients After Brain Tumour Resection
Alina Minnigulova and Maria Khudyakova at the HSE Centre for Language and Brain have presented the latest research findings on the linguistic and neural mechanisms of language impairments and their progression in patients following neurosurgery. The scientists shared insights gained from over five years of research on the dynamics of language impairment and recovery.
Neuroscientists Reveal Anna Karenina Principle in Brain's Response to Persuasion
A team of researchers at HSE University investigated the neural mechanisms involved in how the brain processes persuasive messages. Using functional MRI, the researchers recorded how the participants' brains reacted to expert arguments about the harmful health effects of sugar consumption. The findings revealed that all unpersuaded individuals' brains responded to the messages in a similar manner, whereas each persuaded individual produced a unique neural response. This suggests that successful persuasive messages influence opinions in a highly individual manner, appearing to find a unique key to each person's brain. The study findings have been published in PNAS.
Russian Scientists Improve Water Purification Membranes Using Metal Ions
Researchers have proposed using polymer membranes modified with copper, zinc, and chromium metal ions for water purification. These polymers were used for the first time in water purification via electrodialysis. Copper-based membranes demonstrated record selectivity for monovalent ions, opening new possibilities for sustainable water recycling. The study has been published in the Journal of Membrane Science.
Independent Experts More Effective Than Collective Expertise in Decision-Making Under Uncertainty
A collaborative study by Sergey Stepanov, Associate Professor at the HSE Faculty of Economic Sciences, and experts from INSEAD Business School and NYU Shanghai, indicates that in making decisions under high uncertainty, where it is unclear which choice is superior, advice from independent experts may be more beneficial than a collective opinion from a group of experts. The study has been published in Games and Economic Behavior.