Biology subjects

Silva, M. F.

Publications and source records attributed to Silva, M. F..

4 recordsLinked to original sources

bioRxiv2025

Cell-specific regulation of TCA cycle and cell division related genes at roots following aluminium exposure

Aluminium (Al) toxicity is a critical factor that limits plant growth in acidic soils (pH < 5.5) worldwide. Intracellular Al can bind to various biomolecules and significantly affect gene expression, protein biosynthesis, and cell membrane integrity, ultimately inhibiting nutrients and water uptake. This leads to the arrest of root cell divisions and growth. Organic acids (OAs) produced in mitochondrial-related reactions are strongly linked to Al tolerance, as they bind to Al and neutralize its toxic effects. Recently, the manipulation of root cell divisions through DNA checkpoints has been proposed as an alternative to increase Al tolerance. In this context, molecular interactions between these two mechanisms could potentially enhance plant tolerance to Al toxicity. Here, we investigate this topic using a translatome approach, which enables specific analyses of root cell types (namely, whole root, the quiescent centre region, and the cortical region). This approach offers a promising tool for unravelling how mitochondrial metabolism, particularly the TCA cycle, and the DNA damage response (DDR) pathway are interconnected in Al-mitigation process. Our results revealed that the TCA cycle is induced in differentiated cells, with no significant alteration in meristematic cells, while genes associated with cell cycle progression and DNA checkpoints show differential expression across the distinct cell types. Collectively, our data contribute to understand cell-specific internal detoxification mechanism related to Al tolerance in plants. This knowledge could assist crop breeding by providing a better understanding of the cellular physiological responses to Al toxicity.

plant biology↗

bioRxiv2022

The temporal regulation inter-leaves from domesticated-tomato contrasts with timelessness of its wild ancestors

Cells, tissues, and organs are characterized by harbouring complex systems allowing communication between one another. Plant domestication was demonstrated to have structured the circadian rhythms, while also synchronising flowering and metabolism. Here, we demonstrate that the domesticated tomato (Solanum lycopersicum) manifests more synchronized rhythmicity across the whole plant. Consequently, the leaf development program is more coordinated in this species than in its wild relatives, wherein S. lycopersicum young leaves develop slowly in comparison to mature leaves. Young leaves from wild tomatoes display higher photosynthesis than mature leaves, while large metabolite accumulations occur across plant segments. Consequently, the diel metabolite levels are rather similar between young and mature leaves in the wild tomato S. pennellii, whereas the expression patterns for circadian clock genes are widely contrasting between both leaves. We further demonstrated that additions of genes related to domestication into the wild tomato S. pimpinellifolium appear to synchronize the development of young and mature leaves to be rather similar to that observed for S. lycopersicum. Collectively, the strengthening of inter-organs relationships on domesticated tomato indicates a synchronized biology, which is most likely fundamental to explaining its elevated yield.

plant biology↗

bioRxiv2020

Complexome profile of Toxoplasma gondii mitochondria identifies a divergent cytochrome bc1 complex

The mitochondrial electron transport chain (mETC) and F1Fo-ATP synthase are of central importance for energy and metabolism in eukaryotic cells. The Apicomplexa, important pathogens of humans causing diseases such as toxoplasmosis and malaria, depend on their mETC in every known stage of their complicated life cycles. Here, using a complexome profiling proteomic approach, we have characterised the Toxoplasma mETC complexes and F1Fo-ATP synthase. We identified and assigned 60 proteins to complexes II, IV and F1Fo-ATP synthase of Toxoplasma, of which 16 have not been identified previously. Notably, our complexome profile elucidates the composition of the Toxoplasma complex III, the target of clinically used drugs such as atovaquone. We identified two new homologous subunits and two new parasite-specific subunits, one of which is broadly conserved in myzozoans. We demonstrate all four proteins are essential for complex III stability and parasite growth, and show their depletion leads to decreased mitochondrial potential, supporting their role as complex III subunits. Our study highlights the divergent subunit composition of the apicomplexan mETC complexes and sets the stage for future structural and drug discovery studies. Author SummaryApicomplexan parasites, such as Toxoplasma and Plasmodium, cause diseases of global importance, such as toxoplasmosis and malaria. The mitochondrial electron transport chain (mETC) and F1Fo-ATP synthase, which provide the parasite with energy and important metabolites, are essential for parasite function. Here, using a proteomic technique called complexome profiling, we report the composition of the Toxoplasma mETC and F1Fo-ATP synthase. In particular, we reveal the compositions of complexes II and III for the first time. Complex III is an important drug target, yet its full protein composition was unknown. We identify new parasite-specific complex III subunits and demonstrate that they are essential for parasite survival and for proper functioning of the mETC. Our study highlights the divergent nature of the apicomplexan mETC and F1Fo-ATP synthase.

cell biology↗

bioRxiv2020

Linked deterioration of early visual perception, function and structure in healthy human aging

Low-level visual perception deteriorates during healthy aging. We hypothesized that age-related retinal and cortical structure deteriorations affect perception through specific disruptions of neural function. We measured perceptual visual acuity in fifty healthy adults aged 20-80 years. We then measured these participants early visual field map (V1, V2 and V3) functional population receptive field (pRF) sizes and structural surface areas using fMRI, and their retinal structure using high-definition optical coherence tomography. With increasing age visual acuity decreased, pRF sizes increased, visual field maps surface areas decreased, and retinal thickness decreased. Among these measures, only functional pRF sizes predicted perceptual visual acuity. PRF sizes were in turn predicted by cortical structure only (surface areas), which were only predicted by retinal structure (thickness). We propose that age-related retinal structural deterioration disrupts cortical structure, thereby disrupting cortical functional neural interactions that normally sharpen visual position selectivity: the resulting functional disruption underlies age-related perceptual deterioration.

neuroscience↗