Biology subjects

de Oliveira, A. L.

Publications and source records attributed to de Oliveira, A. L..

3 recordsLinked to original sources

bioRxiv2025

Chemosynthetic Symbioses as Hidden Hubs of DMSP and Organosulfur Cycling in Marine Sediments

Chemosynthetic symbioses between animals and bacteria are known to underpin productivity in the deep sea, yet the diversity of energy and carbon sources sustaining these associations in shallow-water environments remains poorly understood. Dimethylsulfoniopropionate (DMSP) is highly abundant in coastal habitats, where it is produced by seagrasses, phytoplankton, and heterotrophic bacteria, and occurs together with its breakdown product dimethyl sulfide (DMS) in shallow-water sediments. Here we show, supported by genomic and transcriptomic evidence, that DMSP and DMS cycling are integral to the energy and carbon metabolism of the gutless oligochaete Olavius algarvensis and its chemosynthetic symbionts. By assigning DMSP degradation pathways to individual members of the hosts microbial community, we reconstructed a network integrating demethylation and cleavage with energy conservation, methionine biosynthesis, and acetate assimilation into polyhydroxyalkanoates. We also identified a host-encoded methanethiol oxidase (MtoX) suggesting host participation in MeSH detoxification. Comparative metagenomic analyses of more than 60 gutless oligochaete species from globally distributed habitats showed that key DMSP- and DMS-processing genes (dddP, dmdA, tmm, dmsA) are widespread, indicating that organosulfur metabolism is a conserved feature of these symbioses. Our findings expand the recognized metabolic repertoire of shallow-water chemosynthetic symbioses and provide evidence that these associations directly contribute to marine DMSP and DMS cycling.

microbiology↗

bioRxiv2021

Novel insights on obligate symbiont lifestyle and adaptation to chemosynthetic environment as revealed by the giant tubeworm genome

The mutualism between the giant tubeworm Riftia pachyptila and its endosymbiont Candidatus Endoriftia persephone has been extensively researched over the past 40 years. However, the lack of the host whole genome information has impeded the full comprehension of the genotype/phenotype interface in Riftia. Here we described the high-quality draft genome of Riftia, its complete mitogenome, and tissue-specific transcriptomic data. The Riftia genome presents signs of reductive evolution, with gene family contractions exceeding expansions. Expanded gene families are related to sulphur metabolism, detoxification, anti-oxidative stress, oxygen transport, immune system, and lysosomal digestion, reflecting evolutionary adaptations to the vent environment and endosymbiosis. Despite the derived body plan, the developmental gene repertoire in the gutless tubeworm is extremely conserved with the presence of a near intact and complete Hox cluster. Gene expression analyses establishes that the trophosome is a multi-functional organ marked by intracellular digestion of endosymbionts, storage of excretory products and haematopoietic functions. Overall, the plume and gonad tissues both in contact to the environment harbour highly expressed genes involved with cell cycle, programmed cell death, and immunity indicating a high cell turnover and defence mechanisms against pathogens. We posit that the innate immune system plays a more prominent role into the establishment of the symbiosis during the infection in the larval stage, rather than maintaining the symbiostasis in the trophosome. This genome bridges four decades of physiological research in Riftia, whilst simultaneously provides new insights into the development, whole organism functions and evolution in the giant tubeworm.

evolutionary biology↗

bioRxiv2018

The quagga mussel genome and the evolution of freshwater tolerance

European freshwater dreissenid mussels evolved from marine ancestors during the Miocene approximately 30 million years ago and today include some of the most successful and destructive invasive invertebrate species of temperate freshwater environments. Here we sequenced the genome of the quagga mussel Dreissena rostriformis to identify evolutionary adaptations involved in embryonic osmoregulation. We found high gene expression levels of a novel subfamily of lophotrochozoan-specific aquaporin water channel, a vacuolar ATPase and a sodium/hydrogen exchanger during early cleavage, a period defined by the formation of inter-cellular fluid-filled cleavage cavities. Independent expansions of the lophotrochoaquaporin clade that coincide with at least five independent colonisation events of freshwater environments confirm their central role in freshwater adaptation. The pattern of repeated aquaporin expansion and the evolution of membrane-bound fluid-filled osmoregulatory structures in diverse taxa points to a fundamental principle guiding the evolution of freshwater tolerance that may provide a framework for future efforts towards invasive species control.

genomics↗