Porifera Lectins: diversity, physiological roles and biotechnological potential

An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest

Secondary metabolites from Micromonospora ectrinospora G017

Eight  compounds, cyclo-(Pro-Tryp) (1), N-[2-(1H-indol-3-yl)-2-oxo-ethyl] acetamide (2), cyclo-(Pro-Tyr) (3), cyclo-(Pro-Phe) (4), cyclo-trans-4-OH-(Pro-Phe) (5), cyclo-(Pro-Leu) (6), cyclo-(Pro-Val) (7), and  uracil (8) were isolated from the culture broth of the marine Micromonospora ectrinospora G017 strain. The structures of the isolated compounds were established on the basis of their spectral data, including mass spectrometry and NMR

Etude de la diversité microbienne associée à l'éponge carnivore Asbestopluma hypogea

Parmi les 8500 espèces du phylum des Porifères, seules 119 éponges carnivores ont été à ce jour décrites au sein des trois familles Cladorhizidae, Esperiopsidae et Guitarridae, la plupart vivant dans les grands fonds. La découverte en 1996 de l espèce Asbestopluma hypogea (Cladorhizidae) (Vacelet et Boury-Esnault, 1996) dans une grotte méditerranéenne à 17 mètres de profondeur au large de La Ciotat fut l opportunité d étudier cette minuscule éponge, capable de maintenir son cycle de vie en aquarium. Des observations par microscopie électronique à transmission des tissus d A. hypogea ont mis en évidence la présence de nombreux micro-organismes extracellulaires au sein du mésohyle et intracellulaires au sein de bactériocystes. Ces premiers résultats ont stimulé une étude pluridisciplinaire alliant la microbiologie, la métagénomique, la chimie et des observations microscopiques. Nous avons ainsi pu décrire pour la première fois la communauté microbienne associée à l éponge carnivore Asbestopluma hypogea. Afin d accéder à la diversité des procaryotes de A. hypogea nous avons utilisé le pyroséquençage 454 de deux régions du gène de l ARN ribosomal 16S. La comparaison de plusieurs spécimens d éponge prélevés ou conservés en aquarium a révélé une stabilité du microbiome associé. Les résultats obtenus après analyse de 22961 séquences de haute qualité ont permis de mettre en évidence 20 phyla bactériens et deux phyla d archées au sein des éponges analysées. L analyse comparative des séquences obtenues à partir des éponges et celles de l eau de mer a permis de confirmer la spécificité et la stabilité du microbiome associé à l éponge A. hypogea. L analyse des résultats obtenus souligne également l implication potentielle de ces micro-organismes dans les processus biologiques de l éponge. Afin d obtenir des données complémentaires à celles obtenues par métagénomique, nous avons mené l étude du microbiome par une approche culture-dépendante. Plus de 67 isolats, obtenus en culture pure sur différents milieux ont été identifiés après analyse phylogénétique du gène codant l ARN ribosomal 16S, comme appartenant aux Proteobacteria (62%), Firmicutes (27%), Bacteroidetes (7%) et Actinobacteria (4%). Aucune archée n a pu être cultivée bien que leur présence ait été visualisée par CARD-FISH. L évaluation des activités anti-microbienne, anti-oxydante et chitinolytique des isolats obtenus a conduit à la sélection de la souche Streptomyces sp. S1CA, qui possède ces trois types d activité afin d identifier les molécules impliquées. Des premiers travaux de chimie de cette souche ont été entrepris et ont conduit à l isolement de trois composés, l uridine, l uracile et le p-tolyl 3-aminopropanoate. Ce dernier a présenté une activité anti-oxydante. Les molécules actives pourraient avoir un rôle écologique potentiel dans l éponge qui reste à étudier.Among 8,500 species described belonging the Porifera phylum, sole 119 carnivorous sponges were described to date and were classified into the three families Cladorhizidae, Esperiopsidae and Guitarridae, most of them living in the deep-sea. The discovery in 1996 of the species Asbestopluma hypogea (Cladorhizidae) (Vacelet and Boury-Esnault, 1996) in the Mediterranean cave at 17 meters depth off the coast of La Ciotat (France) gave the great opportunity to study this rare species, which can be easily maintained its life cycle in an aquarium. Microscopic observations carried out by transmission electron microscopy highlighted the presence of numerous extracellular microorganisms within the mesohyl of A. hypogea and enclosed in bacteriocyst cells. These first results stimulated a multidisciplinary study using microscopic, culture, molecular biology, metagenomic and chemical approaches. We were able to describe for the first time the microbial community associated with the carnivorous sponge A. hypogea. In order to access to the total microbial diversity of A. hypogea we have used the 454 pyrosequencing of two 16S rDNA gene regions. The comparison of several A. hypogea specimens collected or maintained in aquaria revealed the stability of associated microbiome. More than 22,961 high quality sequences were obtained and allowed the identification of 20 bacterial phyla (50%) and two archaeal phyla (50%) within sponge tissues. Comparative analysis of sequences obtained from sponges and environmental confirmed the specificity and the stability of associated microbiome of the sponge A. hypogea. Analysis of the results also highlight the potential involvement of these microorganisms in biological processes of the sponge. Aiming to obtained complementary data to those obtained by metagenomic, we conducted the study of microbiome by a culture-dependent approach in order to access the cultivable microflora. Overall, 67 isolates were obtained in pure culture using different culture media and identified by the phylogenetic analysis of their 16S rRNA gene into the phyla of Proteobacteria (62%), Firmicutes (27%), Bacteroidetes (7%) and Actinobacteria (4%). No archaeal strain could be cultivated although their presence was visualized by CARD-FISH. Evaluation of antimicrobial, antioxidant and chitinolytic activities of isolates led to the selection of the Streptomyces sp. S1CA revealing the three types of these bioactivities in order to identify molecules responsible. A bioguided chemical approach of this strain was carried out and led to the isolation of three compounds, uridine, uracil and the p-tolyl 3-aminopropanoate. This later exhibited an antioxidant activity. These bioactive molecules could have a potential ecological role within the sponge which remains to be studied.PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Assessing calcareous sponges and their associated bacteria for the discovery of new bioactive natural products.

International audienceAn overview of the chemistry and microbiology of calcareous sponges (Calcispongiae) is provided, highlighting the potential of these sessile filter-feeding marine invertebrates and their associated bacteria for the discovery of new bioactive natural products. 103 compounds are presented and 116 references cited

First insights into the microbiome of a carnivorous sponge

Using 454 pyrosequencing, we characterized for the first time the associated microbial community of the deep-sea carnivorous Demosponge Asbestopluma hypogea (Cladorhizidae). Targeting the 16S rRNA gene V3 and V6 hypervariable regions, we compared the diversity and composition of associated microbes of two individual sponges of A.hypogea freshly collected in the cave with surrounding seawater and with one sponge sample maintained 1year in an aquarium after collection. With more than 22961 high quality sequences from sponge samples, representing c. 800 operational taxonomic units per sponge sample at 97% sequence similarities, the phylogenetic affiliation of A.hypogea-associated microbes was assigned to 20 bacterial and two archaeal phyla, distributed into 45 classes and 95 orders. Several differences between the sponge and seawater microbes were observed, highlighting a specific and stableA.hypogea microbial community dominated by Proteobacteria and Bacteroidetes and Thaumarchaeota phyla. A high relative abundance of ammonia-oxidizing archaea and a dominance of sulfate oxidizing/reducing bacteria were observed. Our findings shed lights on the potential roles of associated microbial community in the lifestyle of A.hypogea

Discovery and preliminary structure–activity relationship studies on tecomaquinone I and tectol as novel farnesyltransferase and plasmodial inhibitors

International audienceBiological screening of a library of synthesized benzo[c]chromene-7,10-dione natural products against human farnesyltransferase (FTase) has identified tecomaquinone I (IC50 of 0.065 ± 0.004 μM) as being one of the more potent natural product inhibitors identified to date. Anti-plasmodial screening of the same library against a drug-resistant strain of Plasmodium falciparum identified the structurally-related dichromenol tectol as a moderately active growth inhibitor with an IC50 3.44 ± 0.20 μM. Two novel series of analogues, based on the benzo[c]chromene-7,10-dione scaffold, were subsequently synthesized, with one analogue exhibiting farnesyltransferase inhibitory activity in the low micromolar range. A preliminary structure–activity relationship (SAR) study has identified different structural requirements for anti-malarial activity in comparison to FTase activities for these classes of natural products. Our results identify tecomaquinone I as a novel scaffold from which more potent inhibitors of human and parasitic FTase could be developed

Synthesis and biological evaluation of the ascidian blood-pigment halocyamine A

International audienceSynthesis of the antimicrobial marine natural product halocyamine A has been achieved utilizing a combination of Sonogashira coupling, ruthenium complex/ytterbium triflate catalyzed hydroamidation and solid-phase peptide synthesis (SPPS) chemistry. The synthetic natural product exhibited only modest levels of antibacterial activities but significant antioxidant activity

Furanoterpene Diversity and Variability in the Marine Sponge Spongia officinalis, from Untargeted LC-MS/MS Metabolomic Profiling to Furanolactam Derivatives

International audienceThe Mediterranean marine sponge Spongia officinalis has been reported as a rich source of secondary metabolites and also as a bioindicator of water quality given its capacity to concentrate trace metals. In this study, we evaluated the chemical diversity within 30 S. officinalis samples collected over three years at two sites differentially impacted by anthropogenic pollutants located near Marseille (South of France). Untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomic profiling (C18 LC, ESI-Q-TOF MS) combined with XCMS Online data processing and multivariate statistical analysis revealed 297 peaks assigned to at least 86 compounds. The spatio-temporal metabolite variability was mainly attributed to variations in relative content of furanoterpene derivatives. This family was further characterized through LC-MS/MS analyses in positive and negative ion modes combined with molecular networking, together with a comprehensive NMR study of isolated representatives such as demethylfurospongin-4 and furospongin-1. The MS/MS and NMR spectroscopic data led to the identification of a new furanosesterterpene, furofficin (2), as well as two derivatives with a glycinyl lactam moiety, spongialactam A (12a) and B (12b). This study illustrates the potential of untargeted LC-MS metabolomics and molecular networking to discover new natural compounds even in an extensively studied organism such as S. officinalis. It also highlights the effect of anthropogenic pollution on the chemical profiles within the sponge