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:
HSE University Develops Tool for Assessing Text Complexity in Low-Resource Languages
Researchers at the HSE Centre for Language and Brain have developed a tool for assessing text complexity in low-resource languages. The first version supports several of Russia’s minority languages, including Adyghe, Bashkir, Buryat, Tatar, Ossetian, and Udmurt. This is the first tool of its kind designed specifically for these languages, taking into account their unique morphological and lexical features.
HSE Scientists Uncover How Authoritativeness Shapes Trust
Researchers at the HSE Institute for Cognitive Neuroscience have studied how the brain responds to audio deepfakes—realistic fake speech recordings created using AI. The study shows that people tend to trust the current opinion of an authoritative speaker even when new statements contradict the speaker’s previous position. This effect also occurs when the statement conflicts with the listener’s internal attitudes. The research has been published in the journal NeuroImage.
Language Mapping in the Operating Room: HSE Neurolinguists Assist Surgeons in Complex Brain Surgery
Researchers from the HSE Center for Language and Brain took part in brain surgery on a patient who had been seriously wounded in the SMO. A shell fragment approximately five centimetres long entered through the eye socket, penetrated the cranial cavity, and became lodged in the brain, piercing the temporal lobe responsible for language. Surgeons at the Burdenko Main Military Clinical Hospital removed the foreign object while the patient remained conscious. During the operation, neurolinguists conducted language tests to ensure that language function was preserved.
AI Overestimates How Smart People Are, According to HSE Economists
Scientists at HSE University have found that current AI models, including ChatGPT and Claude, tend to overestimate the rationality of their human opponents—whether first-year undergraduate students or experienced scientists—in strategic thinking games, such as the Keynesian beauty contest. While these models attempt to predict human behaviour, they often end up playing 'too smart' and losing because they assume a higher level of logic in people than is actually present. The study has been published in the Journal of Economic Behavior & Organization.
Scientists Discover One of the Longest-Lasting Cases of COVID-19
An international team, including researchers from HSE University, examined an unusual SARS-CoV-2 sample obtained from an HIV-positive patient. Genetic analysis revealed multiple mutations and showed that the virus had been evolving inside the patient’s body for two years. This finding supports the theory that the virus can persist in individuals for years, gradually accumulate mutations, and eventually spill back into the population. The study's findings have been published in Frontiers in Cellular and Infection Microbiology.
HSE Scientists Use MEG for Precise Language Mapping in the Brain
Scientists at the HSE Centre for Language and Brain have demonstrated a more accurate way to identify the boundaries of language regions in the brain. They used magnetoencephalography (MEG) together with a sentence-completion task, which activates language areas and reveals their functioning in real time. This approach can help clinicians plan surgeries more effectively and improve diagnostic accuracy in cases where fMRI is not the optimal method. The study has been published in the European Journal of Neuroscience.
For the First Time, Linguists Describe the History of Russian Sign Language Interpreter Training
A team of researchers from Russia and the United Kingdom has, for the first time, provided a detailed account of the emergence and evolution of the Russian Sign Language (RSL) interpreter training system. This large-scale study spans from the 19th century to the present day, revealing both the achievements and challenges faced by the professional community. Results have been published in The Routledge Handbook of Sign Language Translation and Interpreting.
HSE Scientists Develop DeepGQ: AI-based 'Google Maps' for G-Quadruplexes
Researchers at the HSE AI Research Centre have developed an AI model that opens up new possibilities for the diagnosis and treatment of serious diseases, including brain cancer and neurodegenerative disorders. Using artificial intelligence, the team studied G-quadruplexes—structures that play a crucial role in cellular function and in the development of organs and tissues. The findings have been published in Scientific Reports.
New Catalyst Maintains Effectiveness for 12 Hours
An international team including researchers from HSE MIEM has developed a catalyst that enables fast and low-cost hydrogen production from water. To achieve this, the scientists synthesised nanoparticles of a complex oxide containing six metals and anchored them onto various substrates. The catalyst supported on reduced graphene layers proved to be nearly three times more efficient than the same oxide without a substrate. This development could significantly reduce the cost of hydrogen production and accelerate the transition to green energy. The study has been published in ACS Applied Energy Materials. The work was carried out under a grant from the Russian Science Foundation.
HSE Researchers Offer Guidance to Prevent Undergraduate Burnout
Researchers at the HSE Institute of Education have identified how much time students should ideally devote to their studies, extracurricular activities, and personal life to maintain strong academic performance without compromising their mental health. An analysis of responses from 2,753 students, combined with their actual academic results, revealed several risk factors—such as excessive homework—as well as positive factors, including sufficient sleep, regular exercise, and moderate participation in projects. Based on these findings, the researchers developed practical recommendations for both students and universities. The paper has been published in the European Journal of Education.