Biology subjects

Calado, R.

Publications and source records attributed to Calado, R..

3 recordsLinked to original sources

bioRxiv2024

An updated review of the marine ornamental fish trade in the European Union

Wild-caught fishes from coral reefs, one of the most threatened ecosystems on the planet, continue to supply the marine aquarium trade. Despite customs and veterinary checks during imports, comprehensive data on this global industry remains scarce. This study provides an updated review on one of its largest import markets, the European Union (EU): 24-million-euro annual trade value, detailed exporting and importing countries also diversity of species and families of the 26 million specimens imported between 2014 and 2021. We then show how a watchlist alert system based on the number of specimens traded, import trends, and vulnerability index according to FishBase and IUCN Red List conservation status can provide key information on which species should require a closer scrutiny. The stark decline in trade of the most traded species, Chromis viridis, may warrant monitoring through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). While the European TRAde Control and Expert System (TRACES) electronically monitors the movement of live animals to respond quickly to biosecurity risks, one-third of marine ornamental fishes imported lack species-level information. With minor adjustments, TRACES could enhance the monitoring of wildlife trade, with marine ornamental fish being an interesting case study.

scientific communication and education↗

bioRxiv2022

The evolution of two transmissible leukaemias colonizing the coasts of Europe

Transmissible cancers are malignant cell clones that spread among individuals through transfer of living cancer cells. Several such cancers, collectively known as bivalve transmissible neoplasia (BTN), are known to infect and cause leukaemia in marine bivalve molluscs. This is the case of BTN clones affecting the common cockle, Cerastoderma edule, which inhabits the Atlantic coasts of Europe and north-west Africa. To investigate the origin and evolution of contagious cancers in common cockles, we collected 6,854 C. edule specimens and diagnosed 390 cases of BTN. We then generated a reference genome for the species and assessed genomic variation in the genomes of 61 BTN tumours. Analysis of tumour-specific variants confirmed the existence of two cockle BTN lineages with independent clonal origins, and gene expression patterns supported their status as haemocyte-derived marine leukaemias. Examination of mitochondrial DNA sequences revealed several mitochondrial capture events in BTN, as well as co-infection of cockles by different tumour lineages. Mutational analyses identified two lineage-specific mutational signatures, one of which resembles a signature associated with DNA alkylation. Karyotypic and copy number analyses uncovered genomes marked by pervasive instability and polyploidy. Whole-genome duplication, amplification of oncogenes CCND3 and MDM2, and deletion of the DNA alkylation repair gene MGMT, are likely drivers of BTN evolution. Characterization of satellite DNA identified elements with vast expansions in the cockle germ line, yet absent from BTN tumours, suggesting ancient clonal origins. Our study illuminates the evolution of contagious cancers under the sea, and reveals long-term tolerance of extreme instability in neoplastic genomes.

evolutionary biology↗

bioRxiv2021

Photosynthesis from stolen chloroplasts increases sea slug reproductive fitness

Some sea slugs are able to steal functional chloroplasts (kleptoplasts) from their algal food sources, but the role and relevance of photosynthesis to the animal host remain controversial. While some researchers claim that kleptoplasts are slowly digestible snacks, others advocate that they enhance the overall fitness of sea slugs much more profoundly. Our analysis show light-dependent incorporation of 13C and 15N in the albumen gland and gonadal follicles of the sea slug Elysia timida, representing translocation of photosynthates to kleptoplast-free reproductive organs. Long-chain polyunsaturated fatty acids with reported roles in reproduction were produced in the sea slug cells using labelled precursors translocated from the kleptoplasts. Finally, we report reduced fecundity of E. timida by suppressing kleptoplast photosynthesis. The present study provides the first thorough experimental evidence that photosynthesis enhances the reproductive fitness of kleptoplast-bearing sea slugs, confirming the biological relevance of this remarkable association between a metazoan and an algal-derived organelle. TeaserSea slugs incorporate functional chloroplasts from algae and use products of photosynthesis to maximize reproductive output.

ecology↗