No description available.

No description available.

No description available.

No description available.

Infectious disease has always been and will continue to be a heavy burden on human society worldwide. Terrestrial actinobacteria, notable as a source of antibiotics, have been well investigated in the past. In constrast, marine actinobacteria, especially sponge-associated species, have received much less attention and isolates are sparse. With the aim of studying and discovering novel marine actinobacteria, 11 different species of sponges were collected from the Central Red Sea in Saudi Arabia and cultured with three different types of media. 16S rRNA gene-sequencing revealed that among all 75 isolated bacterial strains 13 belonged to the order actinomycetales. These 13 actinomycetes fall into four different families and can be assigned to six different genera. Antibiotic activity tests using disc diffusion assay were performed against Gram-positive bacteria (Bacillus sp.), Gram-negative bacteria (Escherichia coli), fungi (Fusarium sp.) and West Nile virus NS3 protease. Nine strains presented different level of bioactivity against these pathogens. These findings provide evidence that actinomycetes are presented in marine sponges and that they have the potential to be good candidates in the search for new effective antibiotic, antifungal, and antiviral compounds.

No description available.

No description available.

La préservation de la qualité des eaux marines et la lutte contre les pollutions liées à l'activité humaine sont devenues des enjeux mondiaux. De nombreux contaminants biologiques et polluants chimiques se retrouvent dans l’eau de mer, par conséquent dans les produits aquacoles. Ce contexte fait qu’aujourd’hui, les professionnels de la mer sont à la recherche de solutions pour préserver voire améliorer la qualité de leurs eaux. Au sein de notre biodiversité, les éponges marines sont des animaux capables de filtrer 10 000 fois leur volume en eau par jour et de retenir 80% des particules en suspension comme la matière organique, les minéraux, les bactéries et les virus. Par la même occasion, elles accumulent certains éléments traces métalliques comme le plomb, le cadmium ou le cuivre. En collaboration avec le Comité Régional de Conchyliculture de Bretagne Sud, le projet REMEDBIO dans lequel s’inscrit cette thèse se propose d'exploiter le potentiel de filtration des éponges marines du littoral breton. Les objectifs sont de contrôler le développement de bactéries pathogènes et de réduire la présence de polluants chimiques. L’éponge marine Hymeniacidon perlevis (Demospongiae) a été choisie comme modèle pour cette étude. Après avoir mis en évidence la faisabilité de la culture d’éponges marines sur l’estran, notre travail a montré, lors d’essais in vitro, une diminution de la contamination des huîtres par deux bactéries, Escherichia coli et Vibrio aestuarianus, et par le plomb, un élément trace métallique, en présence d’éponges. La dernière phase de ce travail a consisté à valoriser les résultats obtenus. Le projet d’entreprise LECOMER a débuté par le concours START’UBS (lauréat) proposé par l’Université de Bretagne Sud en 2014. Par la suite, LECOMER a été élu lauréat des Trophées de l’Innovation du Morbihan 2014. / The conservation of waters quality and the fight against pollution due to human activities havebecome global issues. Many biological contaminants and chemical pollutants are found in sea water, therefore in aquaculture products. This context fact sea professional are looking for solutions to preserve or even improve the quality of their waters. Among marine biodiversity, marine sponges filter 10 000 times their volume of water per day and retain 80 % of suspended particles such as organic matter, minerals, bacteria and viruses. In addition, sponges are therefore considered as bio-accumulators of metallic trace element such as lead, cadmium or copper. In collaboration with the Comité Régional de Conchyliculture de Bretagne Sud, REMEDBIO project proposes to exploite potential of marine sponges of the Brittany coast. One of the main priorities of this project is to reduce the impact of chemicals (heavy metals) and of biological contaminants (bacteria, viruses) on shellfish breeding. The marine sponges Hymeniacidon perlevis (Demospongiae) was chosen as the model for this study. Having demonstrated the feasibility of the culture of marine sponges on the foreshore, our work has shown, when tested in vitro, reduced contamination of oysters by two bacteria, Escherichia coli and Vibrio aestuarianus, and lead, a metal trace element, in the presence of sponges. The last phase of this work has been to enhance the results. The company LECOMER project began with the START'UBS contest (winner) proposed by the Université de Bretagne Sud in 2014. Thereafter, LECOMER was elected winner of the Innovation Awards of Morbihan in 2014.

>Magister Scientiae - MSc / The discovery of novel secondary metabolites has declined significantly in recent years whereas there is a rise in the number of multi-drug resistant pathogens and other types of diseases. The decline in natural product discovery was due to high rediscovery of already known compounds and the costs in developing natural products. As a result pharmaceutical companies lost interest in investing in natural product discovery. However, there is a renewed interest in marine sponge associated microorganisms as a rich and untapped source of secondary metabolites. The objective of this study was to design a matrix to investigate the extent to which the One Strain-Many Compounds (OSMAC) approach applies to a collection of marine sponge isolates harvested from two South African marine sponge samples. Terminal restriction fragment length polymorphisms (T-RFLP) analysis was used to investigate and ascertain the two marine sponges which hosted the highest microbial diversities to be used for further culture-dependent studies. The culture-dependent studies, using 33 media which included liquid enrichment, heat treatments and antibiotic treatments, resulted in 400 sponge isolates from the two marine sponges Isodictya compressa and Higginsia bidentifera. Using antibacterial overlay assays, 31 dereplicated isolates showed antibacterial activity. Bioactivities were also exhibited against E. coli 1699 which is genetically engineered for resistance against 52 antibiotics which implies that some of the bioactive compounds could be novel. The 16S rRNA gene sequences revealed that the microbial phyla isolated from the marine sponges belonged to Actinobacteria, Firmicutes and Proteobacteria (Alphaproteobacteria and Gammaproteobacteria).Thirty isolates were selected for an OSMAC-based matrix study, 17 of which showed noantibacterial activities in preliminary screening. The application of the OSMAC approach using co-culture and 36 culture conditions resulted in 6 isolates showing antibacterial activities, three of which did not show activities in preliminary screening. One of these, a Bacillus pumilus isolated from I. compressa displayed antibacterial activity against 5 indicator strains whereas in preliminary screening it had not shown activity. The results show that marine sponges can host novel microbial species which may produce novel bioactive compounds. The results also confirm that traditional methods employing a single culture condition restricts the expression of some biosynthetic pathways of microorganisms and as a result many metabolites have yet to be identified.

Neste trabalho descreve-se o estudo química dos extratos de quatro esponjas e dois fungos de origem marinha oriundos da costa do Brasil. Os extratos de três esponjas (Petromica ciocalyptoides, Topsentia ophiraphidites e Callyspongia sp.) apresentaram atividade inibitória à enzima adenosina fosforribosil transferase de Leishmania tarentolae. A partir desses extratos foram isolados 4 compostos. O trissulafato de halistanol, isolado das esponjas P. ciocalyptoides e T. ophiraphidites, e o ilhabelanol, ilhabreno e isoakaterpina, isolados da esponja Callyspongia sp. A partir do extrato bruto da esponja Axinella cf corrugata foram isolados dois derivados cumarínicos, provavelmente artefatos de isolamento do ácido 4-esculetínico, o qual é inédito como produto natural. O extrato bruto da esponja Axinella cf. corrugata apresentou atividade citotóxica, mas os compostos puros não apresentaram esta atividade. Os dois compostos puros foram testados ainda quanto sua atividade contra o vírus da SARS, na qual o éster etílico do ácido 4-esculetínico se apresentou ativo. A partir de dois extratos oriundos do fungo Beauveria felina, isolado da alga marinha Caulerpa sp, foram isoladas 17 frações puras que após diversas análises foram agrupadas em seis compostos conhecidos na literatura: a (Phe3, N-Val5) destruxina B, a cloroidrina da destruxina E, a roseotoxina B, a roseocardina, a isariina e a isariina B. Além disso, foram isolados dois compostos inéditos, a pseudodestruxina C e a cloloidrina Beta-Me-Pro da destruxina E. Os extratos brutos de Beauveria felina apresentaram atividades em bioensaios de atividade antituberculose e de citotoxicidade em linhagem de células de câncer. Os compostos puros avaliados no bioensaio antituberculose não foram ativos. Somente o composto roseotoxina B apresentou atividade citotóxica in vitro para quatro linhagens de células: mama, cólon, sistema nervoso e leucemia. / In this work we report the chemical investigation of bioactive crude extracts obtained from four sponges and two fungal strains of marine origin. The crude extracts of three sponges species (Petromica ciocalyptoides, Topsentia ophiraphidites and Callyspongia sp.) displayed inhibitory activity towards the enzyme adenine fosforribosyl transferase of Leishmania tarentolae (L-APRT). Four compounds have been isolated from these extracts: the known halistanol sulfate was isolated of sponges P. ciocalyptoides and T. ophiraphidites, while the novel ilhabelanol, ilhabrene and isoakaterpin have been isolated from the sponge Callyspongia sp. All compounds exhibited inhibition of L-APRT at micro M concentrations. Two coumarin derivatives have been isolated from the crude extract of the sponge Axinella cf. corrugata, probably as artifacts of isolation: esculetin-4-carboxylic acid methyl ester and esculetin-4-carboxylic acid ethyl ester. While the crude extract of the sponge Axinella cf. corrugata presented cytotoxic activity, the pure compounds were inactive in these assays. The esculetin-4-carboxylic acid ethyl ester was found to be an in vitro inhibitor of SARS virus. The crude extract obtained of a marine-derived Beauveria felina strain, isolated from the alga Caulerpa sp., displayed antituberculosis activity against Mycobacterium tuberculosis H37Rv and cytotoxic activity against MCF-7 (breast), HCT-8 (colon) and B16 (murine melanoma) cancer cell lines. Chemical fractionation of the crude extract led to the isolation of two new cyclodepsipeptides pseudodestruxin C and [Beta-Me-Pro] destruxin E chlorohydrin, and of the known destruxin E chlorohydrin, [Phe3, N-Me-Val5] destruxin B, roseotoxin B, roseocardin, isariin and isariin B. The depsipeptides [Phe3, NMe- Val5] destruxin B and rosetoxin B, have been tested against M. tuberculosis H37 Rv and in cytotoxicity bioassays against SF 295 (human CNS) MDA-MB435 (human breast) HCT8 (colon) and HL60 (leukemia) cancer cell lines. Only roseotoxin B displayed moderate cytotoxicity against the cancer cell lines.