Metabolomic variability of four macroalgal species of the genus Lobophora using diverse approaches

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 marine brown algae (Family: Dictyotaceae) and are widely distributed, especially in tropical coral reefs. The species richness of this genus has only been unveiled recently and it includes species of diverse morphologies and habitats, with some species interacting with corals. This study aims to assess the potential of different metabolomic fingerprinting approaches in the discrimination of four well known Lobophora species (L. rosacea, L. sonderii, L. obscura and L. monticola). These species present distinct morphologies and are found in various habitats in the New Caledonian lagoon (South-Western Pacific). We compared and combined different untargeted metabolomic techniques: liquid chromatography-mass spectrometry (LC-MS), nuclear magnetic resonance (1H-NMR) and gas chromatography (GC-MS). Metabolomic separations were observed between each Lobophora species, with significant differences according to the techniques used. LC-MS was the best approach for metabotype distinction but a combination of approaches was also useful and allowed identification of chemomarkers for some species. These comparisons provide important data on the use of metabolomic approaches in the Lobophora genus and will pave the way for further studies on the sources of metabolomic variations for this ecologically important macroalgae

Chemogeography of the red macroalgae asparagopsis: metabolomics, bioactivity, and relation to invasiveness

Introduction The Latitudinal Gradient Hypothesis (LGH) foresees that specialized metabolites are overexpressed under low latitudes, where organisms are subjected to higher herbivory pressure. The widespread macroalga Asparagopsis taxiformis is composed of six distinct genetic lineages, some of them being introduced in many regions. Objectives To study (i) metabolic fingerprints of the macroalga and (ii) its bioactivity in space and time, both as proxies of its investment in defensive traits, in order to assess links between bioactivities and metabotypes with macroalgal invasiveness. Methods 289 macroalgal individuals, from four tropical and three temperate regions, were analyzed using untargeted metabolomics and the standardized Microtox (R) assay. Results Metabotypes showed a low divergence between tropical and temperate populations, while bioactivities were higher in temperate populations. However, these phenotypes varied significantly in time, with a higher variability in tropical regions. Bioactivities were high and stable in temperate regions, whereas they were low and much variable in tropical regions. Although the introduced lineage two exhibited the highest bioactivities, this lineage could also present variable proliferation fates. Conclusion The metabolomic approach partly discriminates macroalgal populations from various geographic origins. The production of chemical defenses assessed by the bioactivity assay does not match the macroalgal genetic lineage and seems more driven by the environment. The higher content of chemical defenses in temperate versus tropical populations is not in accordance with the LGH and cannot be related to the invasiveness of the macroalgae

Santonja et al. 2019 - Allelopathic effects of pine VOC

Effects of the volatile organic compounds (VOC) released by Pinus halepensis needles and roots on seed germination and seedling growth of two herbaceous target species (Lactuca sativa and Linum strictum

Distance interaction between marine cave-dwelling sponges and crustaceans

Sponges are benthic organisms that are dominant in several ecosystems and known to produce a huge chemical diversity. The putative release of some specialized metabolites in the surrounding seawater is still a matter of debate, but the presence of such compounds in the environment of sponges is thought to influence the behaviour of various mobile organisms and may, thus, contribute to benthic ecosystem structuring and functioning. Underwater Mediterranean caves are characterized by stable environmental conditions and sessile species assemblages dominated by sponges. A two-choice test system was developed to assess the response of two cave-dwelling crustaceans (Hemimysis margalefi and Palaemon serratus) and two other species living in shallow water environments (Leptomysis sp. and Palaemon elegans) to various seawater treatments: control- seawater from an exposed coastline, control+ seawater coming from an underwater cave, and seawater conditioned with four Mediterranean sponges commonly found at the entrance of underwater caves (Aplysina cavernicola, Haliclona fulva, Oscarella tuberculata and Spongia officinalis) or their chemical extracts. We tested the swimming behaviour of these crustacean species in three complementary experiments: (1) control seawater vs. cave seawater; (2) control seawater vs. seawater conditioned with the sponge community, (3) control seawater vs. seawater containing chemical extracts of the same sponge community. Both cave-dwelling crustaceans were attracted by the seawater conditioned with the sponge community, while Leptomysis sp. spent more time in the control seawater and P. elegans exhibited indifferent responses. All four crustacean species avoided the seawater containing the sponge extracts. Interestingly, the response shown by the crustaceans was affected by the time of day. A comparative and untargeted metabolomic approach was applied to the surrounding seawater to identify putative chemomarkers that could explain the crustaceans' behaviours. Among other compounds found in the seawater, a family of metabolites with molecular formulae in accordance with those of oxylipin derivatives is released by sponges and may, therefore, serve as chemical cues acting as kairomones in the homing behaviour of cave-dwelling crustaceans

Pollution gradient leads to local adaptation and small-scale spatial variability of communities and functions in an urban marine environment

International audienceUrbanization of coastal habitats, of which harbors and marinas are the paragon, has led to various ecological paradigms about their functioning. Harbor infrastructures offer new hard substrata that are colonized by a wide variety of organisms (biofouling) including many introduced species. These structures also modify hydrodynamism and contaminant dispersal, leading to strong disturbance gradients within them. Differences in sessile community structure have previously been correlated to these gradients at small spatial scale (< 100 m). Local adaptation might be involved to explain such results, but as correlation is not causation, the present study aims to understand the causal link between the environmental gradients and community structure through a reciprocal transplant experiment among three sites of a marina (inner, middle, entrance). Our results highlighted strong small-scale spatial variations of contaminants (trace metals, PCB, pesticides, and PAH) in sediments and animal samples which have been causally linked to changes in community composition after transplant. But historical contingency and colonization succession also play an important role. Our results provided strong evidence for local adaptation since community structure, respiration, and pollutant uptake in Bugula neritina, as well as the metabolomes of B. neritina and Ciona intestinalis were impacted by the transplant with a disadvantage for individuals transplanted from the entrance to the inner location. The here observed results may thus indicate that the disturbance gradient in marinas might constitute a staple for selecting pollutant-resistant species and populations, causing local adaptation. This highlights the importance of conducting further studies into small scale local adaptation

In Situ Capture and Real-Time Enrichment of Marine Chemical Diversity

International audienc

Discrimination of four marine biofilm-forming bacteria by lc–ms metabolomics and influence of culture parameters

Most marine bacteria can form biofilms, and they are the main components of biofilms observed on marine surfaces. Biofihns constitute a widespread life strategy, as growing in such structures offers many important biological benefits. The molecular compounds expressed in biofilms and, more generally, the metabolomes of marine bacteria remain poorly studied. In this context, a nontargeted LC-MS metabolomics approach of marine biofilm-forming bacterial strains was developed. Four marine bacteria, Persicivirga (Nonlabens) mediterranea TC4 and TC7, Pseudoalteromonas lipolytica TC8, and Shewanella sp. TC11, were used as model organisms. The main objective was to search for some strain specific bacterial metabolites and to determine how culture parameters (culture medium, growth phase, and mode of culture) may affect the cellular metabolism of each strain and thus the global interstrain metabolic discrimination. LC-MS profiling and statistical partial least-squares discriminant analyses showed that the four strains could be differentiated at the species level whatever the medium, the growth phase, or the mode of culture (planktonic vs biofilm). A MS/MS molecular network was subsequently built and allowed the identification of putative bacterial biomarkers. TC8 was discriminated by a series of ornithine lipids, while the P. mediterranea strains produced hydroxylated ornithine and glycine lipids. Among the P. mediterranea TC7 extracts were distinguished by the occurrence of diamine derivatives, such as putrescine amides

Feature-Based Molecular Networks Identification of Bioactive Metabolites from Three Plants of the Polynesian Cosmetopoeia Targeting the Dermal Papilla Cells of the Hair Cycle

The term cosmetopoeia refers to the use of plants in folks’ cosmetics. The aerial parts of Bidens pilosa L., the leaves of Calophyllum inophyllum L. and the fruits of Fagraea berteroana A.Gray ex Benth are traditionally used in French Polynesia for hair and skin care. During the hair cycle, dermal papilla cells and their interaction with epithelial cells are essential to promote hair follicle elongation. The aim of our investigations was the identification of metabolites from these three plants and chemical families responsible for their hair growth activity. A bioactivity-based molecular network was produced by mapping the correlation between features obtained from LC-MS/MS data and dermal papilla cell proliferation, using the Pearson correlation coefficient. The analyses pointed out glycosylated flavonols and phenolic acids from B. pilosa and C. inophyllum, along with C-flavonoids, iridoids and secoiridoids from F. berteroana, as potential bioactive molecules involved in the proliferation of hair follicle dermal papilla cells. Our results highlight the metabolites of the plant species potentially involved in the induction of hair follicle growth and support the traditional uses of these plants in hair car