Biology subjects

Pineda, A.

Publications and source records attributed to Pineda, A..

5 recordsLinked to original sources

bioRxiv2025

Jasmonate-induced prey response in the carnivorous plant Drosera capensis

Drosera capensis is a carnivorous plant native to South Africa. Central to its prey capture and digestive processes is a complex array of biochemical processes triggering the production of both enzymes and small molecules. These processes are in part activated by the release of jasmonic acid, a plant defense hormone repurposed as a prey detection signal. Here, we use RNASeq and untargeted LC-MS metabolomics to study the response of D. capensis to a feeding stimulus. We confirm the expression of digestive proteins predicted in prior genomic work and show up- and downregulation for a number of enzyme classes in response to jasmonic acid. Metabolomics experiments indicate that many small molecules produced during feeding depend on specific nutrient inputs from prey (and not merely a jasmonic acid stimulus). These results shed light on the molecular basis of plant carnivory and the recruitment of existing biochemical pathways to perform specialized functions.

biochemistry↗

bioRxiv2024

Impact of Run-of-River Damming on Increasing Phytoplankton Biomass and Species Shift in a Large Amazonian River: Ecological Implications and Recommendations

Run-of-river (ROR) dams, often perceived as having minimal environmental impact, can induce significant hydrodynamic changes that alter aquatic ecosystems. We investigated the impacts of an ROR dam on the Madeira River, the largest Amazon tributary, focusing on phytoplankton communities, their ecological implications, and related environmental factors. Our study examined changes in biomass and environmental factors (using General Linear Mixed Models - GLMM), species composition (using PERMANOVA) before and after damming, in both the main channel and tributaries (N=549 samples). We also identified indicator species associated with different damming phases and regions through an indicator value analysis. The results showed that, following dam construction, the phytoplankton community changed in both the main channel and tributaries, with a shift from lotic diatoms to lentic phytoflagellates. This transition was likely facilitated by altered hydrodynamics and possibly influenced by the decomposition of flooded vegetation in the dams influence zone. The decomposition of this vegetation could explain both the observed increase in oxygen consumption and the subsequent rise in phytoflagellate biomass after damming. However, despite the overall increase in phytoplankton biomass, the values remained within oligotrophic to mesotrophic conditions, consistent with the low nutrient concentrations recorded. However, we caution that the dam-created hydrodynamic conditions are optimal for phytoplankton growth, potentially exacerbating nutrient-related issues in the future. We recommend proactive management strategies to prevent nutrient enrichment from activities such as agriculture and livestock in isolated Amazon areas affected by dams, thereby mitigating potential water quality degradation linked to increased phytoplankton biomass.

ecology↗

bioRxiv2021

Metabolic alterations in a Drosophila model of Parkinson's disease based on DJ-1 deficiency

Parkinsons disease (PD) is the second most common neurodegenerative disorder whose physiopathology is still unclear. Besides, it is urgent to discover new biomarkers and therapeutic targets to facilitate its diagnosis and treatment. Previous studies performed in PD models and samples from PD patients already demonstrated that metabolic alterations were associated with this disease. In this context, the aim of this study is to give a better understanding of metabolic disturbances underlying PD pathogenesis. To achieve this goal, we used a Drosophila PD model based on inactivation of the DJ-1{beta} gene (ortholog of human DJ-1). Metabolomic analyses were performed in 1-day-old and 15-day-old DJ-1{beta} mutants and control flies using 1H nuclear magnetic resonance spectroscopy, combined with expression and enzymatic activity assays of proteins implicated in altered pathways. Our results showed that PD model flies exhibit protein metabolism alterations, a shift from tricarboxylic acid cycle to glycolytic pathway to obtain ATP, together with an increase in the expression of some urea cycle enzymes. Thus, these metabolic changes could be contributing to PD pathogenesis and might constitute possible therapeutic targets and/or biomarkers for this disease.

neuroscience↗

bioRxiv2020

BETA- AND GAMMA-SYNUCLEINS MODULATE SYNAPTIC VESICLE-BINDING OF ALPHA-SYNUCLEIN

-Synuclein (Syn), {beta}-synuclein ({beta}Syn), and {gamma}-synuclein ({gamma}Syn) are abundantly expressed in the vertebrate nervous system. Syn functions in neurotransmitter release via binding to and clustering synaptic vesicles and chaperoning of SNARE-complex assembly. The functions of {beta}Syn and {gamma}Syn are unknown. Functional redundancy of the three synucleins and mutual compensation when one synuclein is deleted have been proposed, but with conflicting evidence. Here, we demonstrate that {beta}Syn and {gamma}Syn have a reduced affinity towards membranes compared to Syn, and that direct interaction of {beta}Syn or {gamma}Syn with Syn results in reduced membrane binding of Syn. Our data suggest that all three synucleins affect synapse function, but only Syn mediates the downstream function of vesicle clustering and SNARE-complex assembly, while {beta}Syn and {gamma}Syn modulate the activity of Syn through regulating its binding to synaptic vesicles.

neuroscience↗

bioRxiv2019

Plant responses to butterfly oviposition partly explain preference-performance relationships on different brassicaceous species

According to the preference-performance hypothesis (PPH), also known as mother-knows-best hypothesis, herbivorous insects prefer those plants for oviposition, which yield the best offspring performance. Yet, most studies testing the PPH neglect the possibility that plant responses to insect eggs may affect both egg survival and larval performance. Here, we tested the PPH by studying responses of seven Brassicaceae plant species to oviposition by two cabbage white species. When including the egg phase, our study supports the mother-knows-best hypothesis: larvae of Pieris rapae (solitary) or P. brassicae (gregarious) gained most weight on those plant species which had received most eggs (B. nigra or B. montana, respectively). However, our experiments did not reveal any relationship between oviposition preference and egg survival. Brassicaceous species are known to respond to these butterfly eggs with a hypersensitive response (HR)-like necrosis, which can lower egg survival. Pieris eggs frequently induced necrosis in five of the tested plant species. Survival of clustered P. brassicae eggs was unaffected by HR-like in four of the five species. Therefore, our experiments did not reveal any relationship between P. brassicae egg survival and oviposition preference. Females of P. rapae preferred oviposition on plant species which most frequently showed HR-like necrosis. Remarkably, although egg survival was lower on HR-like plants, larval biomass was higher compared to plants without a necrosis. We conclude that egg survival does not seem to be a deciding factor for oviposition choices. However, egg-mediated plant responses might be important to explain the PPH of the two Pieris species.\n\nLay summaryEgg-laying preferences of herbivorous insects can often be linked to offspring performance. Commonly, the fate of insect eggs and the plant responses to the eggs have been ignored when studying the link between preference and performance. By including the egg phase, our study supports the mother-knows-best hypothesis, explained by butterfly oviposition and associated egg and larval performances on different plant species. We especially found that egg-mediated responses seem a deciding factor for butterfly oviposition choices.

ecology↗