Biology subjects

Salam, S.

Publications and source records attributed to Salam, S..

3 recordsLinked to original sources

bioRxiv2023

Mechanical force of uterine occupation enables large vesicle extrusion from proteostressed maternal neurons

Large vesicle extrusion from neurons may contribute to spreading pathogenic protein aggregates and promoting inflammatory responses, two mechanisms leading to neurodegenerative disease. Factors that regulate extrusion of large vesicles, such as exophers produced by proteostressed C. elegans touch neurons, are poorly understood. Here we document that mechanical force can significantly potentiate exopher extrusion from proteostressed neurons. Exopher production from the C. elegans ALMR neuron peaks at adult day 2 or 3, coinciding with the C. elegans reproductive peak. Genetic disruption of C. elegans germline, sperm, oocytes, or egg/early embryo production can strongly suppress exopher extrusion from the ALMR neurons during the peak period. Conversely, restoring egg production at the late reproductive phase through mating with males or inducing egg retention via genetic interventions that block egg-laying can strongly increase ALMR exopher production. Overall, genetic interventions that promote ALMR exopher production are associated with expanded uterus lengths and genetic interventions that suppress ALMR exopher production are associated with shorter uterus lengths. In addition to the impact of fertilized eggs, ALMR exopher production can be enhanced by filling the uterus with oocytes, dead eggs, or even fluid, supporting that distention consequences, rather than the presence of fertilized eggs, constitute the exopher-inducing stimulus. We conclude that the mechanical force of uterine occupation potentiates exopher extrusion from proximal proteostressed maternal neurons. Our observations draw attention to the potential importance of mechanical signaling in extracellular vesicle production and in aggregate spreading mechanisms, making a case for enhanced attention to mechanobiology in neurodegenerative disease.

neuroscience↗

bioRxiv2023

Mesophyll-specific overexpressing of SvHXK6 gene improves water use efficiency without yield loss in C4 Setaria viridis

Hexokinases (HXK) were the first sugar signalling proteins identified in plants and are well known for their feedback regulation of photosynthetic gene expression. In some C3 plants, HXKs have been found to regulate stomatal function. However, the role of HXK in C4 photosynthesis, which is inherently more water use efficient than C3 metabolism, remains poorly understood. Here, we report on the first tissue-specific modification of HXK in a C4 plant. SvHXK6 was expressed in the model C4 grass Setaria viridis under the control of the ZmPEPC promoter (ZmPEPCpro), which directs expression in the leaf mesophyll tissue. Three S. viridis transgenic lines with increased abundance of SvHXK6 transcripts in the leaf tissue showed significant reduction in stomatal conductance with minimal effects on leaf CO2 assimilation rate. Consequently, the transgenic lines had higher leaf-level water use efficiency relative to the control (wild-type and null) plants. Overexpression of SvHXK6 had no effect on shoot biomass or seed yield of the S. viridis plants. Our study shows conserved function of HXK in regulating stomatal conductance in a C4 grass, demonstrating possible widespread utility in improving water use efficiency in C4 as well as C3 species.

plant biology↗

bioRxiv2017

Effort distribution changes effector choice, behaviour and performance: A visuomotor tracking study using finger forces

Human movement and its associated performance are bounded by a hierarchy of constraints operating over certain control variables. One such variable of both physiological and behavioural importance is the mechanical effort exerted by the participating elements. Here, we explored how motor performance is affected by the distribution of work, and consequently the effort.\n\nUsing human hand as a model, we employed a visuomotor tracking task to study the associated motor performance when mechanical effort exerted by the fingers are modulated. The subject has to trace a set of ideal paths provided on visual feedback screen to reach a target through a cursor controlled by index and little finger forces. Modulation of these forces allows us to see how the perceived effort requirement affects the tracking performance. In this task demanding two-element coordination, we represent index finger as the independent/dominant element against little finger as the dependent/subjugate counterpart. We study how increasing mechanical effort contribution from the independent element leads to changes in both behaviour and performance.\n\nWe found that despite higher mechanical requirements of employing index finger to produce larger absolute force, the movement control system continues to prefer it as against little finger which could have produced smaller absolute force. Moreover, the observation of better tracking performance under larger contributions from the independent component reflects to a plausible hierarchy of constraints employed in the motor control system that operates with more than one objective, energy minimisation per se. At least for the behaviour in study, the improved motor performance suggests that the control system prefers higher independence of the participating elements.

neuroscience↗