Biology subjects

Barbiero, M.

Publications and source records attributed to Barbiero, M..

4 recordsLinked to original sources

bioRxiv2022

Cell cycle-dependent binding between Cyclin B1 and Cdk1 revealed by time-resolved Fluorescence Correlation Spectroscopy

Measuring the dynamics with which the regulatory complexes of the cell cycle machinery assemble and disassemble is a crucial barrier to our understanding that until now has been difficult to address. This considerable gap in our understanding is due to the difficulty of reconciling biochemical assays with single cell-based techniques, but recent advances in microscopy and gene editing techniques now enable the measurement of protein-protein interaction kinetics in living cells. Here, we apply Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Cross-Correlation Spectroscopy (FCCS) to study the dynamics of the cell cycle machinery, beginning with Cyclin B1 and its binding to its partner kinase Cdk1 that together form the major mitotic kinase. Although Cyclin B1 and Cdk1 are known to bind with high affinity, our results reveal that in living cells there is a pool of Cyclin B1 that is not bound to Cdk1. Furthermore, we provide evidence that the affinity of Cyclin B1 for Cdk1 increases during the cell cycle, indicating that the assembly of the complex is a regulated step. Our work lays the groundwork for studying the kinetics of protein complex assembly and disassembly during the cell cycle in living cells.

cell biology↗

bioRxiv2019

Gravity highlights a dual role of the insula in internal models

Movements rely on a mixture of predictive and reactive mechanisms. With experience, the brain builds internal representations of actions in different contexts. Many factors are taken into account in this process among which the immutable presence of gravity. Any displacement of a massive body in the gravitational field generates forces and torques that must be predicted and compensated by appropriate motor commands. Studies have shown that the insular cortex is a key brain area for graviception. However, none attempted to address whether the same internal representation of gravity is shared between reactive and predictive mechanisms. Here, participants either mentally simulated (only predictive) or performed (predictive and reactive) vertical movements of the hand. We found that the posterior part of the insular cortex was engaged when feedback was processed. The anterior insula, however, was activated only in mental simulation of the action. A psychophysical experiment shows participants ability to integrate the effects of gravity. Our results demonstrate a dual internal representation of gravity within the insula and discuss how they can conceptually be linked.

neuroscience↗

bioRxiv2019

Visual and auditory information shed light on savings mechanisms

Successful completion of natural motor actions relies on feedback information delivered through different modalities, including vision and audition. The nervous system weights these sensory inflows according to the context and they contribute to the calibration and maintenance of internal models. Surprisingly, the influence of auditory feedback on the control of fine motor actions has only been scarcely investigated alone or together with visual feedback. Here, we tested how 46 participants learned a reaching task when they were provided with either visual, auditory or both feedback about terminal error. In the VA condition, participant received visual (V) feedback during learning and auditory (A) feedback during relearning. The AV group received the opposite treatment. A third group received visual and auditory feedback in both learning periods. Our experimental design allowed us to assess how learning with one modality transferred to relearning in another modality. We found that adaptation was high in the visual modality both during learning and relearning. It was absent in the learning period under the auditory modality but present in the relearning period (learning period was with visual feedback). An additional experiment suggests that transfer of adaptation between visual and auditory modalities occurs through a memory of the learned reaching direction that acts as an attractor for the reaching direction, and not via error-based mechanisms or an explicit strategy. This memory of the learned reaching direction allowed the participants to learn a task that they could not learn otherwise independently of any memory of errors or explicit strategy.

neuroscience↗

bioRxiv2018

The Effects of Varying Gravito-inertial Stressors on Grip Strength and Hemodynamic Responses Across Gender

The body behaves as a global system with many interconnected subsystems. While the effects of a gravitational change on body responses have been extensively studied in isolation, we are not aware of any study that examined two types of body responses concurrently. Here, we examined how the neurocognitive and cardiovascular systems interact in this singular context and whether these combined responses are influenced by gender. Ten women and nine men underwent three 5-minute centrifugation sessions (2.4g at the feet, 1.5g at the heart) in which participants rhythmically moved a hand-held object for 20 seconds. Grip force and hemodynamic responses were continuously measured during centrifugation and rest periods. Our results show that men optimize the modulation between grip force and the destabilizing load force, but not women. Exposure to artificial gravity induced higher heart rate and mean arterial pressure in both genders compared to baseline. However, during exposure, only women decreased heart rate across sessions. Interestingly, we found that Finishers (N=13, mostly men) and Non-Finishers (N=6, mostly women) exhibited divergent patterns of hemodynamic responses. We also suggest that the lack of grip force adaptation reported in women can be linked to challenged hemodynamic responses in that population. Finally, by deriving a simple model to predict failure to complete the experiment, we found that mean arterial pressure was the most relevant dimension, and not gender. As artificial gravity is being proposed as a countermeasure in long-term manned missions, our results are particularly important but also deserve follow-up studies.

physiology↗