Olivier P Thomas

Olivier P Thomas
University of Galway | NUI Galway

Professor
Marine metabolites: from their ecological roles to their use in the bioeconomy

About

262
Publications
58,239
Reads
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3,294
Citations
Citations since 2017
121 Research Items
2283 Citations
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20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
Introduction
The main focus of our research is on marine macro and micro organisms and the metabolites they produce. Sponges and microalgae are our main target groups. Our main expertise is in all the areas of natural product chemistry (HPLC, UPLC, NMR, MS, but also circular dichroism) including metabolic pathways. We also use these metabolites in marine environmental metabolomics to answer ecological and environmental questions.
Additional affiliations
October 2015 - present
University of Galway
Position
  • Established Professor
September 2004 - September 2015
University of Nice Sophia Antipolis
Position
  • Lecturer
October 2002 - August 2004
Atomic Energy and Alternative Energies Commission
Position
  • Post-doctorate

Publications

Publications (262)
Chapter
The term “marine biodiscovery” has been recently been adopted to describe the area of marine natural products dedicated to the search of new drugs. Several maritime countries such as Australia, New Zealand, South Korea, and Japan as well as some European countries have invested significantly in this area of research over the last 50 years. In the l...
Article
Using both multi-informative molecular network and score-based approaches as prioritization strategies, the Northeastern Atlantic marine terebellid Eupolymnia nebulosa was selected for in-depth chemical investigation. A family of 16 new metabolites named nebulosins was isolated and structurally characterized from extensive analyses of HRMS/MS and N...
Article
The chemical investigation of the sponge Stylissa aff. carteri collected around Futuna Islands in the Pacific Ocean led to the isolation of three new dimeric pyrrole 2-aminoimidazole alkaloids (PIAs). Futunamine (1) features an unprecedented pyrrolo[1,2-c]imidazole core, while two other new dimeric PIAs were identified as analogues of palau'amine....
Article
The chemical investigation of marine invertebrates from the deep Northeastern Atlantic revealed new lipoglycotripeptides named characellides isolated from the tetractinellid sponge Characella pachastrelloides. This new family of natural products features a central tripeptide linked to a rare sugar unit and a long alkyl chain ending with a 2,3- dime...
Article
Among the outstanding chemical diversity found in marine sponges, cyclic guanidine alkaloids present in species of the family Crambeidae are particularly attractive, first because of unique chemical features but also due to a broad range of biological activities. Despite a growing interest for these natural products as therapeutic agents, their met...
Article
Full-text available
The dinoflagellate Ostreopsis cf. ovata produces several families of toxic polyketides. Despite only a few field measurements of these phycotoxins in seawater and aerosols, they are believed to be responsible for dermatitis and the toxic inhalations reported during blooms of this species. Therefore, the stability of these compounds in seawater is e...
Preprint
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Coral reefs are of paramount importance in marine ecosystems, where they provide support for a large part of the biodiversity. Being quite sensitive to global changes, they are therefore the prime targets for biodiversity conservation policies. However, such conservation goals require accurate species identification, which are notoriously difficult...
Preprint
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Tropical coral reefs are among the worst affected ecosystems by climate change with predictions ranging between a 70-90% loss of reefs in the coming decades. Effective conservation strategies that maximize ecosystem resilience, and potential for recovery, must be informed by the accurate characterization of extant genetic diversity and population s...
Article
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An Irish strain of the dinoflagellate Amphidinium carterae was previously shown to produce antibacterial amphidinol derivatives of unknown masses. Inspection of the major metabolites present in a bulk culture of this strain led to the isolation and structure elucidation of a new amphidinol derivative named amphidinol C featuring an unprecedented te...
Article
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The present study describes the development of a fit-for-purpose analytical procedure for the detection of Ag NPs in different marine organisms by Solid Sampling Continuous Source High Resolution Atomic Absorption Spectrometry (SS-CS-HR-AAS). The detection is based on the observation of the Ag absorption peak and its atomization delay tad which is...
Article
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Recurrent blooms of the toxic dinoflagellate Ostreopsis cf. ovata are frequently reported in the Northwestern Mediterranean Sea. The impact of these proliferations on other microalgal species inhabiting the same habitats is of interest from an ecological prospective. In vitro experiments were carried out to investigate the influence of O. cf. ovata...
Article
Harmful algal blooms (HABs) represent both ecological and public health hazards in the marine environment. Indeed, some algae can produce metabolites that have negative effects on marine ecosystems and mammals. Kainoid derivatives such as kainic acid (KA) and domoic acid (DA) are considered some of the most toxic metabolites of marine origin biosyn...
Article
Human intoxications in the Mediterranean Sea have been linked to blooms of the dinoflagellate Ostreopsis cf. ovata, producer of palytoxin (PlTX)-like toxins called ovatoxins (OVTXs). Exposure routes include only inhalation and contact, although PlTX-poisoning by seafood has been described in tropical regions. To address the impact of OVTXs on the i...
Preprint
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The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean and the ocean surface waters at 249 locations, resulting in the collection of nearly 58,000 samples. The expedition was designed to systematically study warm coral reefs and included the collection of corals, fish, plankton, and seawater samples...
Article
In recent years, the widespread use of rare earth elements (REEs) has raised the issue of their harmful effects on the aquatic environment. REEs are now considered as contaminants of emerging concern. Despite the increasing interest of REEs in modern industry, there is still a lack of knowledge on their potential impact on the environment and espec...
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Since the introduction of the online open-source GNPS, molecular networking has quickly become a widely applied tool in the field of natural products chemistry, with applications from dereplication, genome mining, metabolomics, and visualization of chemical space. Studies have shown that data dependent acquisition (DDA) parameters affect molecular...
Article
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Antimicrobial resistance (AMR) is a global health challenge with methicillin resistant Staphylococcus aureus (MRSA), a leading cause of nosocomial infection. In the search for novel antibiotics, marine sponges have become model organisms as they produce diverse bioactive compounds. We investigated and compared the antibacterial potential of 3 bis-i...
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An abundant sponge of the order Bubarida was selected for further chemical investigation following biological and chemical screening of sponges collected from Futuna Islands in the Indo-Pacific. Ten new nitrogenous bisabolene derivatives were isolated and identified: the monomeric theonellin formamide analogues named bubaridins A-F (1-6) with unusu...
Article
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Sponges are at the forefront of marine natural product research. In the deep sea, extreme conditions have driven secondary metabolite pathway evolution such that we might expect deep-sea sponges to yield a broad range of unique natural products. Here, we investigate the chemodiversity of a deep-sea tetractinellid sponge, Characella pachastrelloides...
Article
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Introduction La dermatite toxique à algues est liée à l’exposition aux dermatotoxines d’une cyanobactérie marine la Lyngbya majuscula (LM). En 2017, une étude épidémiologique, clinique et environnementale a été menée en Nouvelle Calédonie lors d’une épidémie touchant des personnes fréquentant une même plage. Matériel et méthodes Un cas était défin...
Article
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Microalgae have received growing interest for their capacity to produce bioactive metabolites. This study aimed at characterising the antimicrobial potential of the marine dinoflagellate Amphidinium carterae strain LACW11, isolated from the west of Ireland. Amphidinolides have been identified as cytotoxic polyoxygenated polyketides produced by seve...
Article
The pressing need for SARS-CoV-2 controls has led to a reassessment of strategies to identify and develop natural product inhibitors of zoonotic, highly virulent, and rapidly emerging viruses. This review article addresses how contemporary approaches involving computational chemistry, natural product (NP) and protein databases, and mass spectrometr...
Article
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Marine sponges and their associated microbiota are multicellular animals known to produce metabolites with interesting pharmacological properties playing a pivotal role against a plethora of pathologic disorders such as inflammation, cancer and infections. Characellide A and B belong to a novel class of glycolipopeptides isolated from the deep sea...
Article
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Crambescins are guanidine alkaloids from the sponge Crambe crambe. Crambescin C1 (CC) induces metallothionein genes and nitric oxide (NO) is one of the triggers. We studied and compared the in vitro, in vivo, and in silico effects of some crambescine A and C analogs. HepG2 gene expression was analyzed using microarrays. Vasodilation was studied in...
Article
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The increasing and rapid development in technologies, infrastructures, computational power, data availability and information flow has enabled rapid scientific advances. These entail transdisciplinary collaborations that maximize sharing of data and knowledge and, consequently, results, and possible technology transfer. However, in emerging scienti...
Article
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Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better healt...
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The marine environment is a rich source of biologically active molecules for the treatment of human diseases, especially cancer. The adaptation to unique environmental conditions led marine organisms to evolve different pathways than their terrestrial counterparts, thus producing unique chemicals with a broad diversity and complexity. So far, more...
Article
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This study proposed a novel electrodialysis (ED) system, named anode-ED, which can utilise the anode of ED in situ to electrochemically remove the antibiotics during nutrient (N and P) recovery from animal manure digestate. The oxidation of targeted antibiotics (sulfadiazine, SD; and tetracycline, TC) by the anode of ED was first assessed in a sing...
Article
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In our continuous search for bioactive natural products from marine zoantharians, three serotonin derivatives 1-3 and one dopamine analogue 4 together with the known ecdysteroids ajugasterone C (5) and turkesterone (6) and zoanthoxanthin derivative 3-norpseudozoanthoxanthin (7) were isolated from Zoanthus cf. sansibaricus collected off the coast of...
Article
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Macroalgae constitute one of the preferred substrates of the benthic dinoflagellate Ostreopsis cf. ovata. Across the Mediterranean Sea, this toxic microalga has been shown to thrive on the surface of various species of macroalgae, including Chlorophyta, Rhodophyta, and Phaeophyceae. Interestingly, some Dictyotaceae are characterized by a low abunda...
Article
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Extracts from 26 marine macroalgal species (11 Phaeophyceae, 7 Chlorophyta, and 8 Rhodophyta) sampled from the lagoons of Tahiti, Moorea, and Tubuai (French Polynesia) were tested for several biological activities. The red macroalga Amansia rhodantha exhibited the strongest antioxidant activities using four complementary methodologies (total phenol...
Article
In this work we present an assessment of mercury (Hg) and methyl mercury (MeHg) bioaccumulation in different species of marine sponges collected off the Northwestern Mediterranean and Northeastern Atlantic coasts. Overall the results showed significant accumulation of Hg in sponges, with the Mediterranean sponge Chondrilla nucula exhibiting the hig...
Article
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Cyanobacteria are known to produce a large diversity of specialized metabolites that can cause severe (eco)toxicological effects. In the lagoon of Tahiti, the benthic cyanobacterium Leibleinia gracilis is commonly found overgrowing the proliferative macroalga Turbinaria ornata or dead branching corals. The specialized metabolome of the cyanobacteri...
Article
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Marine organisms produce a vast diversity of metabolites with biological activities useful for humans, e.g. cytotoxic, antioxidant, anti-microbial, insecticidal, herbicidal, anticancer, pro-osteogenic and pro-regenerative, analgesic, anti-inflammatory, anti-coagulant, cholesterol-lowering, nutritional, photoprotective, horticultural or other benefi...
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Worldwide diffused diseases such as osteoarthritis, atherosclerosis or chronic kidney disease are associated with a tissue calcification process which may involve unexpected local stem cell differentiation. Current pharmacological treatments for such musculoskeletal conditions are weakly effective, sometimes extremely expensive and often absent. Th...
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Marine organisms have evolved to survive against predators in complex marine ecosystems via the production of chemical compounds. Soft corals (Cnidaria, Anthozoa, Octocorallia) are an important source of chemically diverse metabolites with a broad spectrum of biological activities. Herein, we perform a comparative study between high-resolution prot...
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The recent description of the polychromatic sponge Plakina kanaky revealed original microsymbionts, with some morphotypes recorded for the first time in Homoscleromorpha, and others never before observed in other sponge groups. Illumina 16S amplicon sequencing was used to characterize this microbial community by comparing contents of seven specimen...
Chapter
The coral reefs of French Polynesia (FP) have experienced repeated macroalgal blooms over the last decades. These events have prompted intense efforts in fundamental and applied research on macroalgae in this ecoregion, especially regarding species of the order Fucales (Turbinaria ornata and Sargassum pacificum). Recently, however, these proliferat...
Article
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This paper reports the isolation and structural characterization of four new ent-kaurane derivatives from the Lamiaceae plant Sideritis hyssopifolia. Planar structures and relative configurations were determined using both mass spectrometry and nuclear magnetic resonance (1D and 2D). Absolute configurations were determined by comparing experimental...
Article
Macroalgae are critical components of coral reef ecosystems. Yet, they compete for space with corals, and in case of environmental disturbances, they are increasingly involved in phase-shifts from coral-dominated to macro-algae-dominated reefs. As regard to climate change, ocean acidification (OA) has been shown to be detrimental to corals and coul...
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Marine aerosols play a significant role in the global radiative budget, in clouds’ processes, and in the chemistry of the marine atmosphere. There is a critical need to better understand their production mechanisms, composition, chemical properties, and the contribution of ocean-derived biogenic matter to their mass and number concentration. Here w...
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Interactions between the ocean and the atmosphere occur at the air-sea interface through the transfer of momentum, heat, gases and particulate matter, and through the impact of the upper-ocean biology on the composition and radiative properties of this boundary layer. The Tara Pacific expedition, launched in May 2016 aboard the schooner Tara, was a...
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Covering: up to the end of 2018 Zoantharians, also improperly known as zoanthids or colonial anemones, are well known by aquarists because of their ease of use in aquaria but also because of their splendid colours. However, high concentrations of the highly toxic palytoxin found in some species of zoantharians maintained in reef aquaria has raised...
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As part of an ongoing program to identify new bioactive compounds from Irish marine bioresources, we selected the subtidal sponge Spongosorites calcicola for chemical study, as fractions of this species displayed interesting cytotoxic bioactivities and chemical profiles. The first chemical investigation of this marine species led to the discovery o...
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Much recent interest has arisen in investigating Streptomyces isolates derived from the marine environment in the search for new bioactive compounds, particularly those found in association with marine invertebrates, such as sponges. Among these new compounds recently identified from marine Streptomyces isolates are the octapeptidic surugamides, wh...
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Coral reefs are the most diverse habitats in the marine realm. Their productivity, structural complexity, and biodiversity critically depend on ecosystem services provided by corals that are threatened because of climate change effects—in particular, ocean warming and acidification. The coral holobiont is composed of the coral animal host, endosymb...
Poster
Perfluorinated compounds (PFAS) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are global emerging environmental contaminants which pose a serious concern to regulators, scientists, and the public worldwide, due to their ubiquitous presence, persistence, toxicity, and potentially bioaccumulative properties. The specific...
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Xestospongia muta is among the most emblematic sponge species inhabiting coral reefs of the Caribbean Sea. Besides being the largest sponge species growing in the Caribbean, it is also known to produce secondary metabolites. This study aimed to assess the effect of depth and season on the symbiotic bacterial dynamics and major metabolite profiles o...
Poster
PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid) broadly known as PFAS are man-made global emerging contaminants detected throughout the environment that have been associated with diverse pathologies including cancer. They are widely used in industrial and agricultural applications including food packaging, water and stain repe...
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So far, the Futuna Islands located in the Central Indo-Pacific Ocean have not been inventoried for their diversity in marine sponges and associated chemical diversity. As part of the Tara Pacific expedition, the first chemical investigation of the sponge Narrabeena nigra collected around the Futuna Islands yielded 18 brominated alkaloids: seven new...
Article
The chemical composition of the marine sponge Phorbas tenacior was investigated in depth. The anchinopeptolides A‐D bearing a central pyrrolidinone were isolated together with a new congener named anchinopeptolide E corresponding to an epimer of anchinopeptolide C. The relative configuration of the central core of anchinopeptolide E was determined...
Article
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The symbiotic association of the leaf-cutter ants with the fungus Leucoagaricus gongylopho-rus implies that the negative impact on the fungi will affect the survival of the ants. After a promising antifungal bioactivity, Carica papaya was studied leading to the bioassay-guided isolation of squalene, 4,5-dihydrohumulen, the flavanol-glycosides querc...
Article
In the search for bioactive marine natural products from zoantharians of the Tropical Eastern Pacific, four new tyrosine dipeptides, named valdiviamides A-D (1-4), were isolated from Antipathozoanthus hickmani, and two new tyramine derivatives, 5 and 6, from Parazoanthus darwini. The phenols of all six tyrosine derivatives are substituted by bromin...
Article
Among comparative metabolomic studies used in marine sciences, only few of them are dedicated to macroalgae despite their ecological importance in marine ecosystems. Therefore, experimental data are needed to assess the scopes and limitations of different metabolomic techniques applied to macroalgal models. Species of the genus Lobophora belong to...
Article
The structures of the commercially available microginins 674 and 690 isolated from a cultured strain of Microcystis aeruginosa and only recently characterized have been revisited. Using NMR and HRMS/MS data, an inversion of two amino acids, N-methylmethionine and tyrosine, in the structure of these metabolites is unambiguously demonstrated. These r...
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Gambierdiscus species are the producers of the marine toxins ciguatoxins and maitotoxins which cause worldwide human intoxications recognized as Ciguatera Fish Poisoning. A deep chemical investigation of a cultured strain of G. belizeanus, collected in the Caribbean Sea, led to the identification of a structural homologue of the recently described...