Biology subjects

Sousa, R.

Publications and source records attributed to Sousa, R..

6 recordsLinked to original sources

bioRxiv2025

Ports of Entry: Tracking Marine Invaders in Portuguese Mari-nas with DNA Metabarcoding from Coast to Archipelagos

Marine non-indigenous species (NIS), introduced primarily through shipping in marinas and ports, pose significant threats to coastal biodiversity and ecosystem functioning, requiring effective management strategies, especially for monitoring aimed at early detection. This study aimed to capture a comprehensive snapshot of the geographic variation of marine invertebrate assemblages and NIS occurrence, across 10 recreational marinas in Portugal (6 on the mainland - Viana do Castelo, Porto, Aveiro (2 marinas), and Lisbon (2 marinas) - and 2 in each archipelago, Madeira and the Azores). In each marina, hard substrates, zooplankton, and water samples (for eDNA) were collected in triplicate during summertime for metabarcoding profiling, adding up to a total of 111 samples. Using Illumina MiSeq sequencing of the mitochondrial cytochrome c oxidase subunit I (COI) gene (313 bp) and the V4 region of the small subunit 18S rRNA gene (18S, approximately 400 bp), we detected 645 species from 21 phyla, 40 of which were NIS (7 phyla). Only 5% of the species and 5% of NIS were detected in all marinas. The highest numbers of both exclusive native species and NIS were recorded in the Azores (100 and 7, respectively), and the lowest numbers of exclusive native species were recovered in Aveiro (39) while the lowest numbers of exclusive NIS were detected in the North and Aveiro regions (1 in each). A Principal Coordinate Analysis indicated a distinct separation among communities forming three main groups: 1) Viana do Castelo, Porto, and Aveiro; 2) Lisbon; and 3) Madeira and the Azores. Similarity between these groups is negatively correlated with geographic distance and overlaps with ecoregions previously identified within Lusitania. In the Azores 9 NIS were recorded for the first time, and one in Madeira. We also recorded a considerable number of potential range expansions of NIS, predominantly along the mainland coast, in both North (N) - South (S) or S-N directions, which shows promising results of the high potential of DNA metabarcoding to be included in future national marine biomonitoring campaigns.

ecology↗

bioRxiv2025

Detection of diadromous fish using environmental DNA: prospects for its use in conservation of endangered species occurring in Portugal

The high economic value and cultural relevance of diadromous fish make them primary targets for traditional fisheries, that need effective management to ensure the long-term survival of their populations. In Portugal, these species are experiencing a marked decline, primarily due to habitat loss and fragmentation, alongside pollution and overfishing. Accurate monitoring is therefore essential to strengthen the management of diadromous fish within Portuguese ecosystems. Advancements in monitoring methodologies could benefit from more sensitive approaches, such as environmental DNA (eDNA) analysis, which is increasingly recognized as a valuable complement to conventional fish monitoring. However, eDNA-based tools remain largely absent and untested in Portugals monitoring and management of diadromous fish. This study reviews literature on eDNA-based detection of diadromous fish species and discusses key methodological aspects influencing the detection efficiency, including sample processing (e.g., water filtration), DNA extraction methods, marker regions and primers, approach and platforms. A particular focus is placed on diadromous fishes occurring in Portugal, which includes several endangered species, and the prospects of using eDNA to monitor them. We also report a pilot study comparing specific assays and DNA metabarcoding in eDNA-based detection of sea lamprey in the Minho River watershed. By consolidating current literature, this work underscores the potential of eDNA to strengthen diadromous fish conservation in Portugal and offers insights to support the integration of eDNA-based tools into national monitoring frameworks. Although our study focuses on Portuguese species, the approaches and insights discussed are broadly applicable and can inform conservation efforts in other regions facing similar challenges. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/645525v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@d5f332org.highwire.dtl.DTLVardef@5171b0org.highwire.dtl.DTLVardef@ff1993org.highwire.dtl.DTLVardef@1e8264f_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2023

Impact of prenatal synthetic glucocorticoid exposure on the adolescent brain

Synthetic Glucocorticoids (sGC) are commonly prescribed in preterm risk pregnancies in order to improve fetal organ maturation. This administration greatly reduces perinatal and neonatal mortality and respiratory distress syndrome associated with prematurity, but preclinical evidence warns for an adverse effect of sGC in the developing brain. In this work we evaluated the long-term effects of prenatal exposure to sGC in the brain of 17 years-old adolescents using multimodal MRI. From 4607 birth registrations from Hospital de Braga - Portugal, we selected participants that were born with similar gestational age, but that were either exposed during pregnancy to sGC (n=21) or non-exposed (n=24). After obtaining a detailed clinical history, participants were subjected to an extensive neuropsychological evaluation, followed by structural and functional MRI. No differences were found in the performance on neuropsychological tests between sGC-exposed and non-exposed participants. Moreover, no differences were found in regional brain volumes. However, the sGC-exposed group presented reduced functional connectivity at rest in a network involving primarily sub-cortical, cerebellar and frontal nodes in comparison to the non-exposed group, even after controlling for confounding factors such as gestational age at birth, birth weight, and sex. Our results suggest that prenatal sGC-exposed adolescents present no significant deviations in neuropsychological performance in the dimensions that we evaluated, although they presented altered functional connectivity, highlighting the need for additional studies to understand the impact of these changes in brain functioning and in behavior. HighlightsPrenatal synthetic glucocorticoid exposure does not lead to structural changes in the adolescent brain. Adolescents prenatally exposed to synthetic glucocorticoids present altered resting state network.

neuroscience↗

bioRxiv2023

Drivers of species knowledge across the Tree of Life

Knowledge of biodiversity is unevenly distributed across the Tree of Life. In the long run, such disparity in awareness unbalances our understanding of life on Earth, influencing policy decisions and the allocation of research and conservation funding. We investigated how humans accumulate knowledge of biodiversity by searching for consistent relationships between scientific (number of publications) and societal (number of views in Wikipedia) interest, and species-level morphological, ecological and socio-cultural factors. Across a random selection of 3,019 species spanning 29 Phyla/Divisions, we show that socio-cultural factors are the most important correlates of scientific and societal interest in biodiversity, including the fact that a species is useful or harmful to humans, has a common name and is listed in the IUCN Red List. Furthermore, large-bodied, broadly distributed and taxonomically unique species receive more scientific and societal attention, whereas colorfulness and phylogenetic proximity to humans correlates exclusively with societal attention. These results highlight a favoritism towards limited branches of the Tree of Life, and that scientific and societal priorities in biodiversity research broadly align. This suggests that we may be missing out on key species in our research and conservation agenda simply because they are not on our cultural radar.

ecology↗

bioRxiv2020

Towards a taxonomically unbiased EU Biodiversity Strategy for 2030

Through the Habitats Directive (92/43/EEC) and the LIFE projects financial investments, Europe has been the world’s experimental arena for biological conservation. With an estimated budget of €20 billion/year, the EU Biodiversity Strategy for 2030 has set an ambitious goal of reaching 30% Protected Areas and ensure no deterioration in conservation trends and status of all protected species. We analyzed LIFE projects focused on animals from 1992 to 2018 and we found that investment towards vertebrates has been six times higher than that for invertebrates (€970 vs €150 million), with birds and mammals alone accounting for 72% species and 75% total budget. Budget allocation is primarily explained by species’ popularity. We propose a roadmap to achieve unbiased conservation targets for 2030 and beyond.Competing Interest StatementThe authors have declared no competing interest.View Full Text

ecology↗

bioRxiv2019

Hsc70 Ameliorates the Vesicle Recycling Defects Caused by Excess -Synuclein at Synapses

-Synuclein overexpression and aggregation are linked to Parkinsons disease (PD), dementia with Lewy bodies (DLB), and several other neurodegenerative disorders. In addition to effects in the cell body, -synuclein accumulation occurs at presynapses where the protein is normally localized. While it is generally agreed that excess -synuclein impairs synaptic vesicle trafficking, the underlying mechanisms are unknown. We show here that acute introduction of excess human -synuclein at a classic vertebrate synapse, the lamprey reticulospinal synapse, selectively impaired the uncoating of clathrin-coated vesicles (CCVs) during synaptic vesicle recycling, leading to a severe depletion of synaptic vesicles. Furthermore, human -synuclein and lamprey {gamma}-synuclein both interact in vitro with Hsc70, the chaperone protein that uncoats CCVs at synapses. After introducing excess -synuclein to lamprey axons, Hsc70 availability was reduced at the synapses, suggesting Hsc70 sequestration as a possible mechanism underlying the synaptic vesicle trafficking defects. In support of this hypothesis, increasing the levels of exogenous Hsc70 together with -synuclein ameliorated the CCV uncoating and vesicle recycling defects. These experiments identify a reduction in Hsc70 availability at synapses, and consequently its function, as the mechanism by which -synuclein induces synaptic vesicle recycling defects. To our knowledge, this is the first report of a viable chaperone-based strategy for reversing the toxic impacts of excess -synuclein at synapses, which may be of value for ameliorating synaptic defects in PD and other synuclein-linked diseases.\n\nSIGNIFICANCE STATEMENTSynaptic defects caused by -synuclein overexpression are linked to cognitive deficits in PD and other diseases. However, the mechanisms by which excess -synuclein impairs synaptic vesicle trafficking are unknown. Data presented here demonstrate that acute introduction of excess -synuclein at a classical vertebrate synapse selectively inhibits CCV uncoating, leading to impaired vesicle recycling. Furthermore, increasing -synuclein reduced synaptic levels of Hsc70, the clathrin uncoating ATPase. Subsequently increasing Hsc70 restored CCV uncoating and improved vesicle recycling. This study identifies a novel molecular mechanism underlying the -synuclein-induced synaptic defects and presents one viable strategy for reversing them.

neuroscience↗