Biology subjects

Dastidar, P. G.

Publications and source records attributed to Dastidar, P. G..

4 recordsLinked to original sources

bioRxiv2026

Stress Granules Buffers Inflammation by Restricting dsRNA-led Mitochondrial Fragmentation

Stress granules (SGs) are dynamic RNA-RBP condensates that form during stress and inflammation, yet how they modulate inflammatory signalling remains unclear. We uncover a rapid, protective SG-mediated mechanism that preserves mitochondrial integrity. During stress and translation inhibition, mitochondrial fragmentation releases double-stranded RNA (dsRNA), which activates PKR and its downstream effector DRP1, generating a self-amplifying loop of mitochondrial fragmentation and inflammation. We find that released dsRNA nucleates nanoSGs within minutes at ER-mitochondria contact sites--the very sites of mitochondrial division. These nanoSGs grow into macroSGs, effectively sequestering PKR-activating dsRNA from the cytosol. By depleting dsRNA, SGs suppress PKR-DRP1-driven positive-feedback inflammation and maintain mitochondrial integrity and function. Our findings reveal SGs as key guardians of mitochondrial homeostasis and position condensate biology at the centre of chronic mitochondrial-driven inflammation relevant to autoimmunity, ageing, and neurodegenerative disease.

cell biology↗

bioRxiv2026

Aging associated RNA loss impairs the dynamics of RNA and protein condensates

Altered biomolecular condensate dynamics are increasingly implicated in age-associated neurodegenerative disorders, yet the molecular principles governing these changes remain incompletely understood. Here, we demonstrate that aged cells across diverse cellular and organismal models harbor pre-formed, viscous, and persistent stress granules (SGs), which we term alt-SGs. These persistent condensates confer protection to senescent cells under fluctuating stress conditions. Comparative analyses reveal that alt-SGs exhibit elevated RNA-binding protein (RBP)-to-RNA ratios, underscoring a shift in condensate stoichiometry. By quantifying SG composition and dynamics in live cells and in vitro, we establish that RNA concentration is a key determinant of condensate material properties, molecular composition, and dissolution capacity. Importantly, aging cells display diminished absolute RNA concentrations due to reduced RNA metabolic activity. Reactivation of RNA metabolism restores RNA/RBP ratios within SGs and alleviates aging-associated phenotypes. Together, our findings highlight RNA metabolism as a central regulator of condensate stoichiometry and function, linking metabolic decline to altered phase behavior and cellular aging. Key findingsO_LIAging and senescence have Alt-SGs with increased protein/RNA Ratio C_LIO_LIAlt-SGs are persistent after stress removal in aging C_LIO_LIAging is associated with reduced total cellular RNA C_LIO_LIReactivating RNA metabolism rescues SG phenotypes C_LIO_LIAlt-SGs are protective for senescent cell C_LI

cell biology↗

bioRxiv2022

Possible Self-awareness in Wild Adelie Penguins Pygoscelis adeliae

This preliminary study, conducted in January-February 2020, investigates the potential presence of self-awareness in a population of wild Adelie penguins on the Dogs Neck Ice Shelf and on Svenner Island in East Antarctica. It is based on the responses and reactions of individual penguins to images, generated in mirrors during three experimental paradigms: a group-behaviour test; a modified mirror test and a hidden-head test. We believe that this set of experiments constitutes possibly the first investigations into the potential presence of self-awareness in any penguin species and is pioneering in conducting a set of cognitive experiments on free-ranging individuals of a nonhuman species in its natural environment, without any prior familiarisation, conditioning or acclimatisation to the experimental paradigms employed. Future studies, integrating the socioecology and cognitive ethology of penguins, may provide insights into whether our experimental paradigms could provide evidence to confirm the presence of self-awareness and even of self-recognition in this species and examine whether the observed social awareness may have evolved due to the social needs of individual penguins to engage in cooperative behaviour with conspecific individuals, while maintaining their independent decision-making capacities, throughout their communal lives.

animal behavior and cognition↗

bioRxiv2019

Three complete genome sequences of Penguin megrivirus from ornithogenic soil, Adelie penguin and Weddell seal of Antarctica

We report the complete genome sequences of Penguin megriviruses from three different sources from Antarctica namely feces of Adelie penguin, feces of Weddell seal and ornithogenic soil. Phylogenetic analysis indicates the prevalence of very similar viruses in different sources of Antarctic environment. These genome sequences aid to understand the evolution of megriviruses in Antarctic ecology and reveal their place in global megrivirus phylogeny.

microbiology↗