Biology subjects

Ribeiro, P.

Publications and source records attributed to Ribeiro, P..

10 recordsLinked to original sources

bioRxiv2025

Environmental Variation Promotes Convergent Evolution and Rapid Diversification of Wing Shape and Color in Skipper Butterflies

Predation is a key driver of speciation and phenotypic diversification, yet how antipredator traits evolve and persist over evolutionary time remains poorly understood. We generated target sequence capture and whole-genome sequencing data for the skipper butterfly subfamily Eudaminae (Hesperiidae) to test whether antipredator defenses, in interaction with environmental variation, promote diversification. We focus on two antipredation wing traits: hindwing tails, which deflect predator attacks, and blue-green coloration, which may enhance motion dazzle and be used as warning coloration. Applying phylogenomics, morphometrics, and comparative methods, we model trait evolution in relation to diel activity and geographic distribution and find that hindwing tails repeatedly evolved at least seven times and blue-green coloration at least fifteen times. Both traits are associated with elevated speciation rates, but evolutionary transitions toward tailless wings and non-iridescent coloration occurred more frequently than trait gains, indicating high evolutionary lability of these antipredator defenses. Trait loss, particularly pronounced in tropical diurnal species, may reflect trade-offs in flight performance, shifts in predation guilds, or the evolution of alternative defensive traits. Our findings highlight rampant convergent evolution of wing traits that are under strong predator-mediated selection. By identifying how antipredator defenses and environmental contexts influence phenotypic and species diversification, this study provides new insights into the ecological and evolutionary processes underlying insect diversity.

evolutionary biology↗

bioRxiv2025

Varietal Reponses of rice (Oryza sativa L.) to different Nitrogen levels under Conventional Production Systems

Rice (Oryza sativa L.) is a vital staple crop globally, with its cultivation expanding to meet increasing demand. In Sub-Saharan Africa, particularly Ghana, rice productivity is often limited by poor soil fertility. Farmers frequently apply high nitrogen (N) fertilizer rates to boost yields; however, excessive nitrogen use contributes to environmental problems such as nutrient leaching and pollution. While optimal nitrogen application rates have been extensively studied, limited research has focused on varietal responses among rice genotypes. This study evaluated the response of five rice varieties (CRI-Agra Rice, Togo Marshall, CRI-Amankwatia, CRI-Enapa, and Jasmine 85) to different nitrogen rates (0, 30, 60, and 90 kg N/ha), focusing on morphophysiological, biomass and yield-related traits. The findings showed significant (p < 0.001) variations in these traits with increasing nitrogen levels. Application of 90 kg N/ha led to substantial improvements: 40% increase in chlorophyll content, 34.3% in culm length, 71.4% in panicle number, 28.3% in straw dry weight and 42.9% in grain yield over the control (0 kg N/ha). Nitrogen significantly promoted vegetative growth, delayed flowering and enhanced biomass and grain production. Genotypic differences in nitrogen use efficiency were also observed. Togo Marshall, CRI-Agra Rice and Jasmine 85 showed over 30% increases in chlorophyll content, while CRI-Enapa exhibited higher plant height and panicle number at 90 kg N/ha. Togo Marshall and CRI-Enapa recorded the highest biomass and yield responses, indicating superior nitrogen utilization. Overall, CRI-Enapa and Togo Marshall performed best at 60-90 kg N/ha. These findings highlight the importance of genotype-specific nitrogen management strategies for improving rice productivity and sustainability in Ghana and similar regions.

plant biology↗

bioRxiv2024

Heat Stress on the brown Seaweed Ascophyllum nodosum: differential population sensitivity to future climate.

Accurate forecasts of the biological impacts of climate change require a better understanding of how small-scale temperature variability affects individual physiology and population dynamics. But doing so for intertidal species with large distribution ranges, while also accounting for the effect of local adaptation, presents numerous technical challenges. Here, we assessed the macroecological consequences of thermal stress on the cold-adapted brown seaweed Ascophyllum nodosum across its European distribution. We collected specimens from ten populations spanning latitudes 41{degrees}N to 60{degrees}N and subjected them to simulated intertidal heat stress using a novel, custom-built experimental setup that replicated realistic conditions, including tidal cycles, light conditions, and temperature trajectories based on in situ data. Our factorial design comprised eight experimental treatments, combining two high-tide water temperatures (15 {degrees}C and 20.5 {degrees}C) with four low-tide peak temperatures (28.5 {degrees}C to 40.5 {degrees}C). Physiological performance was evaluated through measurements of growth, mortality, and oxygen production. Results indicate that thermal stress is more closely associated with the magnitude of temperature change between high and low tides rather than the absolute maximum temperatures reached. Algae exposed to warmer water temperatures (20.5 {degrees}C) consistently outperformed those in colder water (15 {degrees}C), suggesting that cold upwelled waters at the species southern limit may not be essential for survival. Southern populations demonstrated higher resilience to thermal stress than central and northern counterparts. Integrating these physiological responses with climate projections, we employed demographic models to forecast long-term population dynamics. The models predict that future climatic conditions could exceed the thermal resilience of specific populations, leading to uneven impacts across the European distribution of the species. Notwithstanding, range contractions may occur at the warm edge of the distribution, where populations, though more resilient to thermal stress, could still be overwhelmed by the pace of warming. This study underscores the importance of realistic experimental simulations in evaluating species thermal tolerance and highlights the potential for climate change to differentially impact populations along large latitudinal gradients.

ecology↗

bioRxiv2024

Effect of high-intensity anaerobic exercise on electrocortical activity in athletes and non-athletes

AimThe present study aims to verify the information processing in athletes through electroencephalography, analyze cortical areas responsible for cognitive functions related to attentional processing of visual stimuli, and investigate motor activitys influence on cognitive aspects. Material and MethodsThe sample consisted of 29 subjects, divided into an experimental group (n = 13 modern pentathlon athletes) and a control group (n = 16 non-athletes). We collected the electrocortical activity before and after the Wingate Anaerobic Test. During the electrophysiological measures, the volunteers performed a saccadic eye movement paradigm. They also performed cognitive tasks, resting heart rate, and anthropometric measurements. ResultsA mixed ANOVA was applied to analyze the statistical differences between groups (athletes and control) and moments (before and after exercise) for F3, F4, P3, and P4 electrodes during rest one and task (pre-stimulus GO). There was an interaction for the group vs. moment factors in F3 [F = 17,129; p = 0,000; {eta}{superscript 2} = 0.512], F4 [F = 22,774; p = 0,000; {eta}{superscript 2} = 0.510], P3 [F = 11,429; p = 0,001; {eta}{superscript 2} = 0.405], and P4 electrodes [F = 18,651; p = 0,000; {eta}{superscript 2} = 0.379]. We found the main effect for group factors in the frontal and parietal electrodes of the right hemisphere (F4 and P4) and a main effect of the moment factor on the frontal (F3 and F4) and parietal (P3 and P4) electrodes. There was an interaction between the group vs. moment factors for the reaction time. The groups were different in Peak Power (Watts/kg), Average Power (Watts/kg), Fatigue Index (%), and Maximum Power (ms). ConclusionsWe identified chronic effects of exercise training on the cortical activity of modern pentathlon athletes, read-through differences in absolute alpha power, and acute effects of a high-intensity exercise session for athletes and non-athletes for electrocortical and behavioral responses.

neuroscience↗

bioRxiv2024

Attention and working memory investigated through the P300 component in children practicing Karate at different stages of biological maturation

AimTo investigate attention and working memory, comparing children practice Karate and non-Karate practitioners at different stages of biological maturation through the amplitude and latency of the P300 component during the execution of a Go/No-Go paradigm. Material and MethodsThe P300 was analyzed for Fz, Cz, and Pz electrodes in 80 participants separated in two groups: an Karate practitioners group comprising Karate practitioners and comprising non-Karate practitioners. Each group was further subdivided according to the biological maturation range defined by Peak Height Velocity. In addition, the participants performed a Go/No-Go paradigm to measure amplitude and latency. ResultsThe EEG analysis showed Ffr electrodes Pz and Cz, an interaction was found between group and Peak Height Velocity for the amplitude variable (respectively: F = 45.858; d = 0.38; p < 0.001 / F = 10.411; d = 0.17; p = 0.004). For the Fz electrode, a main effect was found between group and Peak Height Velocity (respectively: F = 40.330; d = 0.34; p = 0.010 / F = 36.730; d = 0.30; p = 0.012) for the variable amplitude and latency. main effect between group and Peak Height Velocity (respectively: F = 7.719; d = 0.14; p = 0.012 / F = 38.370; d = 0.31; p = 0.010). ConclusionsIn general, it is possible to conclude that participants in the Karate practitioners group exhibited electrocortical measures corresponding to greater efficiency in decision-making and attention processes, motor planning, working memory, attention allocation, motor execution, and greater attentional engagement. It was also demonstrated that, despite the children being at very close chronological ages, their biological maturation differed.

neuroscience↗

bioRxiv2024

The Effects of Acute Coordinative vs. Acute Endurance Exercise on the Cortisol Concentration

BackgroundPhysical exercise interventions can cause neuroendocrine activation, which in turn increases salivary cortisol concentrations. Until now there have been no studies comparing endurance and coordinative exercise. ObjectiveThe purpose of this study was to examine the effects of these different interventions with an intraindividual comparison. Methods61 students between 18 and 30 years of age were included and first completed a coordinative exercise and one week later an endurance exercise of the same intensity and length which was self-set on the first day, with a maximum heart rate of 64 - 76% (HRmax) over a period of 15 min. To measure changes in the hypothalamic-pituitary-adrenal axis (HPA-axis) activity, saliva samples were collected before (t1) and after exercise (t2 and t3). ResultsBaseline values of cortisol (t0) did not differ significantly between coordinative and endurance exercise, t(55) = .233, p = .816. Post hoc tests revealed that the cortisol values of the second coordinative vs. endurance time point, t(55) = 2.097, p = .040, d = .741, and third coordinative vs. endurance time point, t(55) = 3.004, p = .004, d = .735, differed significantly with large effect sizes. ConclusionThe results show for the first time that coordinative exercise produced a higher cortisol release than endurance exercise of the same intensity and duration. Interventions such as coordinative exercise require higher cognitive components resulting in stronger cortisol release than endurance exercise. Thus, the type of acute exercise is a psychophysiological factor in determining the neuroendocrine stress response. Key pointsCortisol is an important catabolic hormone when it comes to overtraining or burnout in an athlete. Our results show for the first time that acute coordinative exercise produces a higher cortisol release than endurance exercise of the same intensity and duration.

physiology↗

bioRxiv2023

Decrease in reaction time for volleyball athletes during saccadic eye movement task: An associative analysis with evoked potentials

AimThe current study investigated the differences to event-related potential and reaction time under two groups (athletes vs. non-athletes). Material and MethodsThe P300 was analyzed for Fz, Cz and Pz electrodes in thirty-one healthy volunteers divided into two groups (volleyball athletes and non-athletes). In addition, the participants performed a saccadic eye movement task to measure reaction time. ResultsThe EEG analysis showed that the athletes in comparison to the no-athletes has differences of the P300 in the frontal area (p=0.021). In relation to reaction time, the results show lower reaction time for athletes (p=0.001). ConclusionsThe volleyball athletes may present a greater allocation of attention during the execution of the inhibition task, since they have a lower reaction time for responses when compared to non-athletes.

neuroscience↗

bioRxiv2022

Inflammation-induced mitochondrial and metabolic disturbances in sensory neurons control the switch from acute to chronic pain

Pain often persists in patients with inflammatory diseases, even when the inflammation has subsided. The molecular mechanisms leading to this failure in resolution of inflammatory pain and the transition to chronic pain are poorly understood. Mitochondrial dysfunction in sensory neurons has been linked to chronic pain, but its role in resolution of inflammatory pain is unclear. Transient inflammation causes neuronal plasticity, called hyperalgesic priming, which impairs resolution of hyperalgesia induced by a subsequent inflammatory stimulus. We identified that hyperalgesic priming in mice caused disturbances in mitochondrial respiration, oxidative stress, and redox balance in dorsal root ganglia (DRG) neurons. Preventing these priming-induced disturbances restored resolution of inflammatory hyperalgesia. Concurrent with these mitochondrial and metabolic changes, the expression of ATPSc-KMT, a mitochondrial methyltransferase, was increased in DRG neurons in primed mice. ATPSc-KMT overexpression in DRG neurons of naive mice induced similar mitochondrial and metabolic changes as observed after priming, leading to failure in pain resolution. Inhibition of mitochondrial respiration, knockdown of ATPSCKMT expression, or NAD+ supplementation were sufficient to restore resolution of inflammatory pain and prevent chronic pain development. Thus, inflammation-induced mitochondrial-dependent disturbances in DRG neurons promote failure in inflammatory pain resolution and drive the transition to chronic pain.

neuroscience↗

bioRxiv2021

Gut microbiota diversity and C-Reactive Protein are predictors of disease severity in COVID-19 patients

Risk factors for COVID-19 disease severity are still poorly understood. Considering the pivotal role of gut microbiota on host immune and inflammatory functions, we investigated the association between changes in gut microbiota composition and the clinical severity of COVID-19. We conducted a multicentre cross-sectional study prospectively enrolling 115 COVID-19 patients categorized according to: 1) WHO Clinical Progression Scale - mild 19 (16.5%), moderate 37 (32.2%) or severe 59 (51.3%); and 2) location of recovery from COVID-19 - ambulatory 14 (household isolation; 12.2%), hospitalized in ward 40 (34.8%) or intensive care unit 61 (53.0%). Gut microbiota analysis was performed through 16S rRNA gene sequencing and data obtained was further related with clinical parameters of COVID-19 patients. Risk factors for COVID-19 severity were identified by univariate and multivariable logistic regression models. In comparison with mild COVID-19 patients, the gut microbiota of moderate and severe patients has: a) lower Firmicutes/Bacteroidetes ratio, b) higher abundance of Proteobacteria; and c) lower abundance of beneficial butyrate-producing bacteria such as Roseburia and Lachnospira genera. Multivariable regression analysis showed that Shannon index diversity (odds ratio [OR] 2.85 [95% CI 1.09-7.41]; p=0.032) and C-Reactive Protein (OR 3.45 [95% CI 1.33-8.91]; p=0.011) were risk factors for COVID-19 severe disease (a score of 6 or higher in WHO clinical progression scale). In conclusion, our results demonstrated that hospitalised moderate and severe COVID-19 patients have microbial signatures of gut dysbiosis and for the first time, the gut microbiota diversity is pointed out as a prognostic biomarker for COVID-19 disease severity.

microbiology↗

bioRxiv2019

Assessing the impact of mindfulness attitudes on attentional quality through focused breath induction.

Mindfulness attitudes, as gentleness, openness, acceptance, curiosity and being non-judgmental have been related to improvement in cognitive and emotional functions, but few studies have focused on its specific contribution. The present study investigated the effect of the mindfulness attitudes on top-down attentional control abilities. Twenty one healthy participants were submitted to two conditions: a Mindfulness induction session where participants practiced focusing on the sensory sensations of breathing while encouraged to incorporate the five mindfulness attitudes and an attentional control session in which participants were repeatedly instructed to merely attend to the breath, without any mindfulness attitude component. Before and after each condition, participants performed two blocks of the oddball task while EEG was recorded. Contrary to our expectations, attentional control assessed through amplitude and latency of the P3b ERP component and oddball task accuracy did not show any changes in any of the conditions. These results suggest that a low dose of mindfulness training in naive individuals, through a focused breath induction, is not enough to improve the allocation of attentional resources towards task-relevant stimuli.

neuroscience↗