Biology subjects

Machado, C.

Publications and source records attributed to Machado, C..

3 recordsLinked to original sources

bioRxiv2025

From egg to adult: comprehensive (e)DNA metabarcoding monitoring of fish diversity in a temperate estuary

Monitoring fish species through ichthyoplankton surveys provides important information for fish stock assessment and management. To test the effectiveness of DNA metabarcoding to identify fish species and to capture seasonal variations in local ichthyofauna, monthly ichthyoplankton and 2 L water samples were collected over 13 months in the lower section of the Guadiana River Estuary in southeast Portugal. Both sample types underwent high-throughput sequencing for three genetic markers (COI, 12S, 16S), with morphological identification also performed for ichthyoplankton. Bulk and water samples identified a total of 131 fish species throughout the year. DNA metabarcoding demonstrated higher taxonomic resolution and diversity detection, with 115 species recovered, while morphology identified only 23 species. Ichthyoplankton metabarcoding also detected 40% more fish than water eDNA, recovering almost the double of species despite the fact that both approaches used the same metabarcoding primers. The integration of multiple molecular markers was crucial to maximize diversity detection in both DNA-based methods. In addition, DNA metabarcoding was able to identify ichthyofaunal spawning periods and captured significant seasonal variations in fish community, with higher diversity observed during the warmer months. With this strategy, around 66% of the historically recorded ichthyoplankton taxa in the region were identified, along with several new records. The findings demonstrated the capability of (e)DNA metabarcoding to uncover seasonal variations in the regional fish community, provided new insights on the ichthyofauna of the Guadiana Estuary, and revealed the need for more in-depth studies to improve the efficiency of multiple sampling methods for fish species identification.

molecular biology↗

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↗