Biology subjects

Serrao, E.

Publications and source records attributed to Serrao, E..

4 recordsLinked to original sources

bioRxiv2024

Revealing Hidden Threats: Marine Invertebrate Invasions in the Banc d'Arguin National Park (PNBA), Mauritania, Explored Through DNA Barcoding

The Banc dArguin National Park (PNBA) in Mauritania, a globally significant biodiversity hotspot, faces growing threats from human activities and biological invasions. This study aimed to document marine invertebrate diversity in the PNBA and identify non-native and potentially invasive species. Samples were collected during expeditions in 2021 and 2022, using scuba-diving, drag dredging, and manual intertidal collection across depths of 0 to 20 meters. Through DNA barcoding of COI and 16S genes, 17 species from three phyla--Cnidaria, Bryozoa, and Arthropoda-- were identified, with several cryptic taxa detected. Evidence of human-mediated introduction was found in hydroids (Bougainvillia, Pennaria, Obelia), bryozoans (Amathia, Bugula, Schizoporella), and barnacles (Amphibalanus), suggesting invasions from regions like Brazil, and the Indo-Pacific. Notably, Amathia brasiliensis and Amathia cf. vidovici were recorded for the first time in West Africa, alongside the detection of two other Amathia species, raising concerns about their potential impact on the PNBAs biodiversity and ecosystem services. The presence of these exotic species, likely introduced via international maritime traffic and fishing activities, highlights the parks vulnerability. The study underscores the utility of DNA barcoding for detecting cryptic diversity and tracking species dispersal, recommending urgent conservation measures and biosecurity protocols to protect the PNBAs unique marine ecosystems.

zoology↗

bioRxiv2023

Unravelling the role of oceanographic connectivity in intra-specific diversity of marine forests at global scale

AimIntra-specific diversity results from complex interactions of intermingled eco-evolutionary processes along species history, but their relative contribution has not been addressed at the global scale. Here, we unravel the role of present-day oceanographic connectivity in explaining the genetic differentiation of marine forests across the ocean. LocationGlobal. Time periodContemporary. Major taxa studiedMarine forests of brown macroalgae (order Fucales, Ishigeales, Laminariales, Tilopteridale). MethodsThrough systematic literature revision, we compiled a comprehensive dataset of genetic differentiation, encompassing 662 populations of 34 species. A biophysical model coupled with network analyses estimated multigenerational oceanographic connectivity and centrality across the marine forest global distribution. This approach integrated species dispersive capacity and long-distance dispersal events. Linear mixed models tested the relative contribution of site-specific processes, connectivity, and centrality in explaining genetic differentiation. ResultsWe show that spatiality dependent eco-evolutionary processes, as described by our models, are prominent drivers of genetic differentiation in marine forests (significant models in 92.6 % of the cases with an average R2 of 0.49 {+/-} 0.07). Specifically, we reveal that 19.6 % of variance is explicitly induced by contemporary connectivity and centrality. Moreover, we demonstrate that LDD is key in connecting populations of species distributed across large water masses and continents. Main conclusionsWe deciphered the role of present-day connectivity in observed patterns of genetic differentiation of marine forests. Our findings significantly contribute to the understanding of the drivers of intra-specific diversity on a global scale, with implications for biogeography and evolution. These results can guide well-informed conservation efforts, including the designation of marine protected areas, as well as spatial planning for genetic diversity in aquaculture, which is particularly relevant for sessile ecosystems structuring species such as brown macroalgae.

ecology↗

bioRxiv2022

LGR5 targeting molecules as therapeutic agents for multiple cancer types

Leucine-rich repeat-containing G-protein receptor 5 (LGR5) has been characterised as a stem cell and cancer stem cell marker. Previous analyses of LGR5 transcript levels indicate high level expression discriminates malignancies such as colorectal cancer (CRC) and pre-B acute lymphoblastic leukaemia (pre-B ALL) from healthy tissues suggesting LGR5 protein expression may provide a molecular handle for prognosis and treatment. We have developed highly specific, high affinity antibodies to the extracellular domain of human LGR5 (-LGR5) that detect high LGR5 protein levels in colorectal cancer (CRC), hepatocellular carcinoma (HCC), and pre-B ALL. In contrast, there is low to undetectable levels of LGR5 protein in normal colon and rectal epithelia, liver, ovarian tissues, brain and immune cell types. LGR5 is rapidly internalised from the plasma membrane and trafficked to intracellular vesicular compartments including lysosomes. Treatment of high LGR5-expressing CRC and pre-B ALL cancer cell lines with an antibody-drug conjugate version of -LGR5 (-LGR5-ADC) lead to effective cell killing at nanomolar concentrations. Interventional treatment of pre-B ALL tumours with -LGR5-ADC in vivo led to rapid tumour attrition. We further demonstrated the therapeutic utility of humanised -LGR5 by using the corresponding scFv fragment for the generation of -LGR5 chimeric antigen receptors (CARs) and a Bispecific T cell Engager (BiTE). -LGR5-CAR-NK cells were effective at killing LGR5-expressing cells while -LGR5/-CD3 BiTEs induce T cell activation and killing of NALM6 cells by cytotoxic CD8+ T cells. Taken together, this study establishes -LGR5-based therapeutic modalities that effectively discriminate and target CRC, HCC and pre-B ALL tumour cells. One Sentence SummaryWe generated novel antibodies against the cancer cell marker LGR5, validated diagnostic use in prioritizing specific cancer types for targeting, and developed antibody-based therapeutics.

cell biology↗

bioRxiv2019

Sex-dependent and -independent transcriptional changes during haploid phase gametogenesis in the sugar kelp Saccharina latissima

In haplodiplontic lineages, sexual reproduction occurs in haploid parents without meiosis. Although widespread in multicellular lineages such as brown algae (Phaeophyceae), haplodiplontic gametogenesis has been little studied at the molecular level. We addressed this by generating an annotated reference transcriptome for the gametophytic phase of the sugar kelp, Saccharina latissima. Transcriptional profiles of microscopic male and female gametophytes were analysed at four time points during the transition from vegetative growth to gametogenesis. Gametogenic signals resulting from a switch in culture irradiance from red to white light activated a core set of genes in a sex-independent manner, involving rapid activation of ribosome biogenesis, transcription and translation related pathways, with several acting at the post-transcriptional or post-translational level. Additional genes regulating nutrient acquisition and key carbohydrate-energy pathways were also identified. Candidate sex-biased genes under gametogenic conditions had potentially key roles in controlling female- and male-specific gametogenesis. Among these were several sex-biased or - specific E3 ubiquitin-protein ligases that may have important regulatory roles. Females specifically expressed several genes that coordinate gene expression and/or protein degradation, and the synthesis of inositol-containing compounds. Other female-biased genes supported parallels with oogenesis in divergent multicellular lineages, in particular reactive oxygen signalling via an NADPH-oxidase. Males specifically expressed the hypothesised brown algal sex-determining factor. Male-biased expression mainly involved upregulation of genes that control mitotic cell proliferation and spermatogenesis in other systems, as well as multiple flagella-related genes. Our data and results enhance genome-level understanding of gametogenesis in this ecologically and economically important multicellular lineage.

genomics↗