Biology subjects

Maric, A.

Publications and source records attributed to Maric, A..

5 recordsLinked to original sources

bioRxiv2026

The Pan-European Impact of the Balkan Hunter-Gatherers

During the Last Glacial Maximum (LGM) 26-19 thousand years ago (kya), Europe had three principal refugia not covered by ice: the Iberian, Italian, and Balkan peninsulas1,2. While the Iberian and Italian refugia have been studied with ancient DNA3-7, the legacy of the Balkan refugium has remained a mystery due to a lack of genetic data 30-12 kya. We present genome-wide data from nine newly reported individuals: three Epipaleolithic from Romania, one Epipaleolithic from Bosnia and Herzegovina, three Mesolithic from Greece, one Epipaleolithic from Southern Italy, and one Mesolithic from Sardinia. We find that the Epipaleolithic individuals from Romania and the Mesolithic individual from mainland Greece were from a previously unsampled population that was the primary source for later European hunter-gatherers. Westward expansion of Balkan Epipaleolithic people into the Italian Peninsula and mixture with a minority contribution from pre-LGM Italians, produced a population that then spread further west to become the primary ancestry of west-ern European Mesolithic people. Northeastward expansion, bypassing Italy, contributed the European ancestry source of Scandinavian and Eastern European hunter-gatherers. Southeastward expansion to the Aegean led to Anatolian-European mixtures before the spread of farming.

genetics↗

bioRxiv2026

Alterations in sleep state boundaries and sleep dynamics following acute total and chronic partial sleep loss: a state space model exploration

Chronic partial and acute total sleep loss have a distinct impact on sleep architecture. Namely, acute sleep deprivation primarily leads to a strong rebound of slow wave sleep, while chronic sleep restriction results in an increased propensity of REM sleep. The aim of this work was to examine whether these different effects would translate into quantifiable changes in sleep state boundaries and dynamics using a model-based method. Besides conventional sleep stage scoring, we applied an EEG model (state space approach) for dynamic analysis of nocturnal EEG recordings in 14 healthy subjects under experimental chronic sleep restriction (last of 7 nights with 5 hours of time in bed) and after acute sleep deprivation (sleep following 40 hours of wakefulness), in comparison to baseline sleep. Subjects under chronic sleep restriction revealed increased similarities in the frequency composition of REM sleep and wakefulness and thus, a decreased differentiation of state boundaries between the two behavioral states. Contrarily, acute sleep deprivation affected the spectral composition of NREM sleep. Only acute sleep deprivation resulted in more stable slow wave sleep. Our explorative study confirmed that the distinct effects of increased REM sleep and slow wave sleep propensity following acute total and chronic partial sleep loss are reflected in differential changes of behavioral state boundaries and sleep dynamics. This suggests that these sleep structure characteristics are state dependent, which may allow using such measures in the future to track treatment effects in clinical populations characterized by sleep behavioral state dysregulation.

neuroscience↗

bioRxiv2026

An oxygen-sensing Polycomb-group protein encodes flooding stress memory in plants

Most organisms, including plants, can encode stress memories that improve resilience to repeated environmental challenges. Flooding events expose plants to recurrent hypoxia, yet whether plants establish an adaptive memory of flooding is unclear. Here we show that somatic flooding stress memory is a conserved feature across multiple angiosperm species. In Arabidopsis, this memory depends on the oxygen-sensitive Polycomb Repressive Complex 2 (PRC2) subunit VERNALIZATION2 (VRN2). Loss of VRN2 impairs epigenetic memory formation and disrupts transcriptional memory at key genes that promote anthocyanin accumulation and repress leaf senescence, adaptive responses that enhance flooding tolerance. Collectively, we reveal a molecular mechanism where VRN2-PRC2 acts as both an oxygen sensor and chromatin effector to establish adaptive flooding stress memory in plants. ShortOur work defines a molecular mechanism for flooding stress memory in plants, actioned via the PRC2 subunit VRN2, that acts as the direct molecular (low) oxygen sensor and transducer. Coupled to its role in cold sensing, this identifies VRN2 as a master sensor subunit of the plant PRC2 that integrates multiple environmental cues to modulate the chromatin landscape and encode environmental memory.

plant biology↗

bioRxiv2026

The compartmentalized activity of a legume subtilase SBT12a allows symbiosome stabilization

The stabilization of rhizobia in specialized organelles, called symbiosomes, is an evolutionary hallmark for maintaining high rates of nitrogen fixation in legumes. This is achieved by releasing thousands of bacteria from nodular infection threads within in a single plant cell, which poses a great challenge for the host to keep control over these differentiated bacteria. Considering the importance of proteolytic degradation of antimicrobial proteins or generation of symbiosis-promoting peptides, proteolytic activity may represent a key regulatory system. Indeed, we identified the Medicago truncatula subtilisin-like protease (subtilase, SBT) 12a acting as a novel regulator of symbiosome functionality and maintenance. Loss-of-function mutations in SBT12a led to severe symbiotic defects with nodules of sbt12a being characterized by high level induction of defense/senescence-related genes. Using untargeted proteomic High-efficiency Undecanal-based N-Termini EnRichment (HUNTER) we identified and individually confirmed specific SBT12a target proteins that are involved in plant defense responses and symbiosome maintenance. This positions SBT12a as a central host factor controlling symbiosome performance.

plant biology↗

bioRxiv2024

Longer Interstimulus Intervals Enhance Efficacy of Automated Phase-Targeted Auditory Stimulation on Procedural Memory Consolidation

Up-phase-targeted auditory stimulation (up-PTAS) during slow-wave sleep has become a valuable tool for modulating slow oscillations and slow-oscillation-spindle-coupling in favor of overnight memory retention. Developing effective, automated protocols for translation into more naturalistic or clinical settings is an ongoing challenge, especially given that current PTAS protocols and their behavioral effects vary greatly between different studies. Here, we assessed the electrophysiological and behavioral effects of systematically varying interstimulus intervals (ISIs) in automated up-PTAS in the home setting, using a mobile PTAS device and app-based behavioral tasks. Building on studies suggesting a non-linear relationship between stimulus number and PTAS effects, we show that applying fewer stimuli with longer ISIs enhanced overnight memory consolidation of a finger-tapping sequence more effectively than applying more stimuli with shorter ISIs. The behavioral response was predicted by the number of stimuli with auditory evoked K-complexes relative to the number of stimuli without K-complexes. PTAS stimuli applied at longer ISIs (> 1.25) were associated with a higher likelihood of K-complex responses and fast spindles nesting in the K-complex up-phase. Our results suggest that up-PTAS can be optimized for overnight memory consolidation by introducing ISIs of at least 1.25s. Our study highlights the feasibility of longitudinal at-home PTAS combined with app-based behavioral tasks in healthy participants while leveraging the mechanistic insights such data can offer. Statement of SignificancePhase-targeted auditory stimulation (PTAS) holds great promise for non-invasively enhancing essential functions of slow-wave sleep. However, current protocols have produced variable results and are often confined to laboratory settings. Our study demonstrates the feasibility of a mobile application of automated PTAS and provides experimental evidence that prolonging interstimulus intervals positively affects overnight procedural memory consolidation via K-complexes and coupled sleep spindles. As K-complexes may also be involved in cardiovascular function and brain waste clearance, the proposed protocol optimization may have effects beyond memory enhancement. Together, our findings lay a foundation for a broader application of PTAS in clinical longitudinal studies to improve patient care and recovery outcomes.

neuroscience↗