Estudios de bioprospección del coral blando Pseudopterogorgia elisabethae como fuente de sustancias con actividad biológica Fase IV

Con el fin de ampliar el potencial de aplicación del octocoral Pseudopterogorgia elisabethae de la Isla de Providencia (Caribe Sur Occidental), se aislaron e identificaron nueve compuestos: las pseudopterosinas PsG, PsP, PsQ, PsS, PsT, PsU y 3-O-acetil- PsU y las seco-pseudopterosinas: seco-PsJ y seco-PsK, a los cuales junto con la mezcla en equilibrio de diterpenos no glicosidados (MEDNG aislada de P. elisabethae de la Isla de San Andrés) se les determinó un perfil citotóxico mas completo contra cinco líneas célulares humanas (HeLa (cáncer cervical), PC-3 (cáncer de próstata), HCT116 (cáncer colorectal), MCF-7 y BJ (fibroblastos normales de piel)) y se les determinó por primera vez la actividad antimicrobiana contra cuatro microorganismos patógenos (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa y Candida albicans). Los resultados mostraron que todas las sustancias evaluadas presentaron una citotoxicidad moderada no selectiva, en donde las PsQ y PsG fueron los compuestos más activos (GI50 5.8 μM-12.0 μM). Con respecto a la actividad antimicrobiana todos los compuestos mostraron una buena y selectiva actividad contra las bacterias Grampositivas, siendo las PsU, PsQ, PsS, seco-PsK y PsG los compuestos mas activos contra S. aureus (IC50 2.9–4.5 μM) y las PsG, PsU y seco-PsK contra E. faecalis (IC50 3.1–3.8 μM). Paso seguido en la línea de prospección propuesta se hizo necesario buscar la producción sustentable (suministro) de estos compuestos de modo que se pudiera disponer de cantidades apreciables de ellos para seguir con los procesos de evaluación clínica y posterior aplicación industrial. Teniendo en cuenta que en los últimos años, crecientes evidencias han implicado a los microorganismos simbióticos como la fuente biosintética de diferentes metabolitos aislados de a partir de una gran variedad de invertebrados marinos, en el presente trabajo se caracterizó por primera vez para un octocoral de agua superficial a nivel mundial, la comunidad bacteriana asociada con P. elisabethae de la Isla de Providencia (considerando que ella pudiera ser la verdadera responsable de la producción de los compuestos tipo Ps y seco-Ps), empleando métodos dependientes (cultivo en diferentes medios de las diluciones del homogeneizado y del raspado de la superficie de muestras del octocoral) e independientes de cultivo (pirosecuenciación de los 16S rDNA y DGGE). Como resultado se lograron aislar e identificar 40 bacterias pertenecientes a las clases Bacilli (15 cepas), Actinobacteria (12 cepas), Gammaproteobacteria (9 cepas), Alphaproteobacteria (3 cepas) y Betaproteobacteria (1 cepa). Los resultados de los análisis independientes de cultivo de la comunidad bacteriana total asociada con tres individuos de P. elisabethae reveló que la comunidad bacteriana se compone de 12 phyla, de los cuales Proteobacteria (54.06% a 86,39%) fue el phylum mas abundante seguido de Bacteroidetes (1.98% a 2.68%), Cyanobacteria (0.27% a 4.54%), Actinobacteria (0.49% a 1,15%) y Firmicutes (0.15% a 0.20%). Gammaproteobacteria fue la clase más abundante (46.80% a 80.03%), seguido por Alphaproteobacteria (4.34% a 6.61%), Cyanobacteria (0.27% a 4.54%) y Sphingobacteria (0.92% a 2.55%). Pseudomonas spp. y Spongiobacter spp. fueron identificados como los filotipos más abundantes. Adicionalmente, considerando que la comunidad bacteriana simbionte total asociada a P. elisabethae está compuesta principalmente por bacterias Gram-negativas y que además las Ps y seco-Ps aisladas de este mismo octocoral presentaron una actividad selectiva contra las bacterias Grampositivas, se planteó la hipótesis de que estos compuestos podrían tener un posible papel ecológico controlando químicamente los organismos que se asientan (fouling) en la superficie del octocoral. Para comprobar lo anterior se evaluó la capacidad de los compuestos aislados para inhibir el crecimiento y formación del biofilm bacteriano de seis cepas aisladas de superficies marinas cubiertas con fouling, como un indicador de su actividad antifouling, así como también la actividad antimicrobiana de estos compuestos contra las bacterias aisladas de la superficie del propio octocoral. Los resultados mostraron que las Ps y seco-Ps modulan el crecimiento bacteriano (inhibiendo el crecimiento de bacterias Gram-positivas e induciendo la asociación a superficies de las bacterias Gram-negativas). Así, por primera vez se da soporte experimental al posible papel de estas sustancias en la selección de los organismos asociados a la superficie de P. elisabethae y la regulación de la composición de la comunidad bacteriana simbiótica del octocoral, lo cual puede estar relacionado con el hecho de que P. elisabethae mantenga una superficie limpia, libre del crecimiento de micro- y macrofouling excepto por sus propios microrganismos simbiontes. Por otro lado vale la pena resaltar que a partir de los resultados obtenidos por primera vez en este trabajo para la actividad antimicrobiana de las Ps y seco-Ps contra bacterias aisladas de superficies con fouling, se amplia el potencial de aplicación de estas sustancias como agentes antifouling. Adicionalmente, teniendo en cuenta que la mayoría de agentes antifouling conocidos no son efectivos contra algunas especies bacterianas y diatomeas, las Ps y seco-Ps como agentes capaces de controlar la formación de comunidades bacterianas se convierte en una solución para potencializar diferentes tratamientos contra el problema del fouling. Finalmente, para evaluar la capacidad de las bacterias cultivables asociadas con P. elisabethae para producir compuestos químicos (entre ellos Ps y seco-Ps) bioactivos o no bioactivos se realizó un screening químico y un screening biológico de los productos de cultivo de las 40 bacterias aisladas en este trabajo, en cuatro medios diferentes. Para ello se planteó una nueva metodología que permitió la miniaturización de los cultivos por triplicado (5.0 mL) en cuatro medios diferentes, junto con la extracción en fase sólida empleando la resina diaion HP-20 y el uso de la tecnología UPLC-MS de como herramienta química para la detección rápida de compuestos producidos (screening químico) por las 40 bacterias, logrando determinar que ninguna de las bacterias estudiadas es capaz de producir compuestos tipo Ps, seco-Ps y compuestos relacionados en las condiciones de cultivo empleadas. Sin embargo, mediante el análisis de los resultados de UPLC-MS empleando el software XcaliburTM del equipo se logró obtener una librería de 46 compuestos producidos por 14 bacterias del phylum Firmicutes, para los cuales haciendo uso de la base de datos Antibase 2007TM como herramienta de derreplicación se sugiere la estructura de 10 de ellos: amicoumacina A, amicoumacina B, cloroxantomicina, 3-acetoamido-3-deoxi-beta-D-glucopiranosa, ansamitocina PDM-0, bruceantarina, bruceantina, pyloricidina D, Al-77-D y ansamitocina PDM-4. Por su parte, el screening biológico de los extractos del cultivo de las 40 bacterias en los cuatro medios, se utilizó como herramienta para determinar la producción de sustancias con actividad biológica por parte de alguna de las bacterias en un medio de cultivo determinado. Para ello los extractos fueron evaluados contra S. aureus, E. faecalis, P. aeruginosa y C. albicans. Los resultados mostraron que todas las bacterias son fuente de compuestos con actividad antibiótica contra al menos un microrganismo ensayado. En donde la mayoría de Actinobacterias, cuando fueron cultivadas en el medio B, producen sustancias capaces de inhibir el crecimiento de E. faecalis y S. aureus, mientras que cuando fueron cultivadas en TSB, solo presentaron actividad contra S. aureus. Por el contrario ninguno de los extractos de este grupo presentó una considerable actividad contra P. aeruginosa ni contra C. albicans. Por su parte el grupo de bacterias Firmicutes cuando fueron cultivadas en medios bajos en nutrientes (MMB y NB/10) produjeron sustancias con actividad contra C. albicans. Finalmente, las Proteobacterias fueron capaces de producir sustancias con actividad contra S. aureus y C. albicans cuando fueron cultivadas en los medios E1, MMB y NB-IO, mientras que su cultivo en el medio TAK parece favorecer la producción de sustancias con actividad contra E. faecalis. De este primer análisis se pudo seleccionar los extractos de las bacterias y los medios de cultivo que presentaron los mejores resultados de actividad antimicrobiana y finalmente, seleccionar dos Actinobacterias Brevibacterium casei y Brachybacterium conglomeratum para realizar su escalamiento a un litro de cultivo. Posteriormente, los extractos del cultivo de estas dos bacterias fueron sometidos a un fraccionamiento bioguiado, el cual permitió encontrar las fracciones responsables de la actividad antimicrobiana mostrada por cada uno de los extractos. Sin embargo, debido a la poca cantidad obtenida de dichas fracciones no se pudo continuar con su estudio para poder identificar los compuestos presentes en ellas. / Abstract. The goal of this research was to expand the potential application of the octocoral Pseudopterogorgia elisabethae of Providencia Island (southwest Caribbean Sea). In the present work, nine compounds were isolated and identified. The pseudopterosins: PsG, PsP, PsQ, PsS, PsT, PsU and 3-O-acetil-PsU and the seco-pseudopterosins: seco-PsJ and seco-PsK, together with the inter-converted mixture of non-glycosylated diterpenes (IMNGD isolated from P. elisabethae of San Andres Island) their anti-microbial profiles were screened for the first time against four pathogenic microorganisms (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans). Also reported is a more complete cytotoxic profile against five human cells lines (HeLa, PC-3, HCT116, MCF-7 and BJ). For the cytotoxic profiles, all compounds evaluated showed moderate and non-selective activity against both tumor and normal cell lines, where PsQ and PsG were the most active compounds (GI50 values between 5.8 μM to 12.0 μM). With respect to their anti-microbial activity the compounds showed good and selective activity against the Gram-positive bacteria, while they did not show activity against the Gram-negative bacterium or yeast. PsU, PsQ, PsS, seco-PsK and PsG were the most active compounds (IC50 2.9–4.5 μM) against S. aureus and PsG, PsU and seco-PsK showed good activity (IC50 3.1–3.8 μM) against E. faecalis To continue with the bio-prospecting proposal it became necessary to seek sustainable production (supply) of these compounds so that there would be appreciable amounts to continue with the process of clinical evaluation and subsequent industrial application. Therefore, it was endeavoured to characterize the composition of the bacterial community associated with Colombian P. elisabethae, as a growing body of evidence has implicated symbiotic microorganisms as the biosynthetic source of metabolites isolated from a variety of marine invertebrates. Eventual identification of a bacterium capable of producing Ps and seco-Ps would open a biotechnological route to the production of these promising metabolites. To characterize the bacterial community associated with P. elisabethae from Providencia Island, both culture dependent (dilution plating of homogenized octocoral onto a variety of agar media) and culture independent (pyrosequencing of 16S rDNA amplicons and DGGE) approaches were employed. Culture dependent analysis resulted in the identification of 40 unique bacteria classified as Bacilli (15 strains), Actinobacteria (12 strains), Gammaproteobacteria (9 strains), Alphaproteobacteria (3 strains) and Betaproteobacteria (1 strain). Culture independent analysis of the bacterial communities associated with three P. elisabethae individuals revealed that the bacterial communities were composed of 12 phyla of which Proteobacteria (54.06% to 86.39%) was the most abundant followed by Bacteroidetes (1.98% to 2.68%), Cyanobacteria (0.27% to 4.54%), Actinobacteria (0.49% to 1.15%) and Firmicutes (0.15% to 0.20%). Gammaproteobacteria was the most abundant class (46.80% to 80.03%) followed by Alphaproteobacteria (4.34% to 6.61%), Cyanobacteria (0.27% to 4.54%) and Sphingobacteria (0.92% a 2.55%). Pseudomonas spp. and Spongiobacter spp were identified as the most abundant phylotypes associated with P. elisabethae. To the best of our knowledge this is the first characterization of the bacterial diversity associated with P. elisabethae collected from Colombian waters. Additionally, these results showed that the bacterial community associated with P. elisabethae is composed principally by Gram-negative cells and also that Ps and seco-Ps showed selective activity against eukaryotic and prokaryotic cells. It was hypothesized that these compounds may have a potential ecological role by chemically controlling the organisms settling on (fouling) the surface of octocoral. Therefore, their activity against bacteria associated with heavily fouled marine surfaces was evaluated as an indicator of antifouling activity. Additionally, their activity against the normal microbiota of P. elisabethae was assessed to determine whether they played a role on the octocoral surface. So, with experimental support, it has shown the possible ecological role of these substances for the first time, where the Ps and seco-Ps seem to modulate bacterial growth (inhibiting Gram-positive bacterial growth and inducing Gram-negative bacteria association with surfaces). This might suggest a role as chemical modulators of epibiosis on the surface of P. elisabethae. These results suggest that Ps and seco-Ps might have a role in the selection of organisms associated with the octocoral surface and in the regulation of the symbiotic bacterial community composition, which might be related to the clean surface of P. elisabethae. On the other hand, according to the antimicrobial activity of the Ps and seco-Ps against bacteria isolated from fouling surfaces, it is possible to extend the potential application of these substances as antifouling agents. Also, due to the fact that most known antifouling agents are not effective against bacterial and diatom species, the Ps and seco-Ps can be combined with existing antifouling agents to increase their potential applications Finally, to assess the ability of cultivable bacteria associated with P. elisabethae to produce chemical compounds (including Ps and seco-Ps) bioactive or non-bioactive, chemical and a biological screening of the substances produced by the 40 bacteria in four different media was carried out. This gave rise to a new methodology that allowed the miniaturization of triplicate cultures (5.0 mL) in four different media. Along with solid phase extraction using Diaion resin HP-20 and the use of UPLC-MS technology as a chemical tool for rapid screening of compounds produced (chemical screening). Using this methodology it was determined that none of the 40 bacteria studied is capable of producing Ps, seco-Ps or either related compounds in the culture conditions used. However, through the analysis of UPLC-MS chromatograms using the equipment software (XcaliburTM) a library of 46 compounds produced by 14 bacteria of the phylum Firmicutes was developed. Using the database Antibase2007TM as a dereplication tool, the structure of 10 of these compounds were identified as: amicoumacin A, amicoumacin B, cloroxantomicin, 3-deoxy-3-acetoamide-beta-D glucopyranose, ansamitocin PDM-0, bruceantarin, bruceantin, pyloricidin D, Al-77-D and ansamitocin PDM-4. Additionally, a biological screening was done to determine the production of antibiotics for the 40 bacteria in the four media. The extracts of the cultures were evaluated against S. aureus, E. faecalis, P. aeruginosa and C. albicans. The results showed that all the bacteria isolated were sources of compounds with antibiotic activity, since all the extracts showed activity against at least one microorganism tested. Most of the Actinobacteria, when they were cultured in medium B, produced substances capable of inhibiting the growth of E. faecalis and S. aureus, whereas when they were grown in TSB the extracts just showed activity against S. aureus. In contrast none of the extracts from this group presented a significant activity against P. aeruginosa or C. albicans. The group of FirmiDoctorad

Anti-inflammatory effects of the gorgonian Pseudopterogorgia elisabethae collected at the Islands of Providencia and San Andrés (SW Caribbean)

<p>Abstract</p> <p>Background</p> <p>We are reporting for the first time the <it>in vivo </it>anti-inflammatory activity of extracts and fractions, and <it>in vitro </it>anti-inflammatory activity of pure compounds, all isolated from <it>Pseudopterogorgia elisabethae </it>collected at the Providencia (chemotype 1) and San Andrés (chemotype 2) Islands (SW Caribbean).</p> <p>Methods</p> <p>Extracts from <it>P. elisabethae </it>were fractionated on silica gel to yield fractions: F-1 (pseudopterosins PsQ, PsS and PsU) and F-2 (amphilectosins A and B, PsG, PsK, PsP and PsT and <it>seco</it>-pseudopterosins <it>seco</it>-PsJ and <it>seco</it>-PsK) from chemotype 1, and F-3 (elisabethatrienol, 10-acetoxy-9-hydroxy- and 9-acetoxy-10-hydroxy-amphilecta-8,10,12,14-tetraenes (interconverting mixture) and amphilecta-8(13),11,14-triene-9,10-dione) from chemotype 2. By using preparative RP-HPLC and spectroscopic means, we obtained the pure PsG, PsK, PsP, PsQ, PsS, PsT, PsU, <it>seco</it>-PsK and the interconverting mixture of non-glycosylated diterpenes (IMNGD). The anti-inflammatory properties of extracts and fractions were evaluated using <it>in vivo </it>model "12-<it>O</it>-tetradecanoyl-phorbol-acetate (TPA)-induced mouse ear oedema". The activities of pure compounds and of the IMNGD were evaluated using <it>in vitro </it>assays myeloperoxidase (MPO) release (by human polymorphonuclear neutrophils (PMNs)), nitric oxide release (by J-774 cells) and scavenger activity on NO.</p> <p>Results</p> <p>In the <it>in vivo </it>anti-inflammatory assay, extracts and F-3 showed low inhibition levels of inflammation compared to indomethacin, F-1 and F-2. Additionally, we evaluated the MPO release to the inflammation site, and found a marked inhibition of MPO levels by all extracts and fractions, even superior to the inhibition shown by indomethacin.</p> <p>Furthermore, in the MPO <it>in vitro </it>assay, IMNGD, PsQ, PsS, PsT and PsU, exhibited higher inhibition levels compared to dexamethasone and indomethacin. In the NO release <it>in vitro</it>, IMNGD, PsP and PsT were the most potent treatments. Finally, because the PsG, PsP and <it>seco</it>-PsK did not exhibit any NO scavenger activity, they should inhibit the inducible Nitric Oxide Synthase (iNOS) or other routes that influence this enzyme. Alternatively, PsQ, PsS, and PsU did show scavenger activity.</p> <p>Conclusion</p> <p>All results presented contribute to demonstrate that the compounds isolated in this work from <it>P. elisabethae </it>are promising molecules with an interesting anti-inflammatory activity profile. Additionally, the results obtained could provide preliminary insights towards their structure-activity relationship.</p

Aproximación al estudio de la interacción entre aristolochia maxima y larvas de la mariposa battus polydamas polydamas y parides panares erythrus mediada por ácidos aristolóquicos

Las mariposas de la tribu Troidini (Lepidoptera: Papilionidae) capturan los ácidos aristolóquicos (AAs) provenientes de su alimentación larval en plantas de Aristolochiaceae para su protección. En este estudio se detectó la presencia de los ácidos aristóloquicos I y II (AA-I y AA-II) en hojas jóvenes de Aristolochia maxima (Aristolochiaceae) y en larvas de las mariposas Battus polydamas polydamas y Parides panares erythrus (Papilionidae, Papilioninae) por Cromatografía Líquida de Alta Eficiencia (CLAE). De acuerdo con los resultados de los perfiles cromatógraficos por CLAE, el AA-I fue el ácido aristolóquico mayoritario encontrado tanto en las larvas como en las hojas jóvenes de la planta, seguido por cantidades menores del AA-II. Estos resultados permiten afirmarque la interacción planta-animal entre las mariposas de las especies B. polydamas y P. panares y las plantas de A. maxima, está mediada, por los ácidos aristóloquicos I y II.Most butterflies of the tribe Troidini (Lepidoptera: Papilionidae) sequester aristolochic acids (AA) for their protection. These acids are derived from their host plants -family Aristolochiaceae- upon which they feed on during their larval stages. Using analytical High Performance Liquid Chromatography (HPLC) methods we were able to detect the presence of aristolochic acids I and II both in the young leaves of Aristolochia maxima (Aristolochiaceae) and in the caterpillars of the butterflies Battus polydamas polydamas and Parides panares erythrus (Papilionidae, Papilioninae). Aristolochic acid I was the major constituent found, followed by lesser amounts of Aristoloquic acid II. These results confirm that the host-animal interaction among butterflies of the studied species and A. maxima plants is mediated, by aristolochic acids

Does Osmotic Stress Affect Natural Product Expression in Fungi?

Acknowledgments: Russell Kerr acknowledges the assistance of Nadia Prigoda-Lee, Marius Grote, Kate McQuillan and Stephanie Duffy, and generous financial support from NSERC, the Canada Research Chair program, the Jeanne and Jean-Louis Lévesque Foundation and the Atlantic Canada Opportunities Agency. Ka-Lai Pang thanks the president of National Taiwan Ocean University, Ching-Fong Chang, for a special fund to attend the workshop held in Charlottetown, Canada in 2014 where this work was discussed. Rob Capon and Zhuo Shang acknowledge support from the University of Queensland, and the UQ Institute for Molecular Bioscience. Zhuo Shang acknowledges the provision of an International Postgraduate Research Scholarship (IPRS) and a Centennial Scholarship by the University of Queensland. Catherine Roullier acknowledges the assistance of Marie-Claude Boumard and Thibaut Robiou du Pont, and support from Region Pays de la Loire, FrancePeer reviewedPublisher PD

Cytotoxic and Antimicrobial Activity of Pseudopterosins and seco-Pseudopterosins Isolated from the Octocoral Pseudopterogorgia elisabethae of San Andrés and Providencia Islands (Southwest Caribbean Sea)

To expand the potential of pseudopterosins and seco-pseudopterosins isolated from the octocoral Pseudopterogorgia elisabethae of San Andrés and Providencia islands (southwest Caribbean Sea), we report the anti-microbial profile against four pathogenic microorganisms (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans) and report a more complete cytotoxic profile against five human cells lines (HeLa, PC-3, HCT116, MCF-7 and BJ) for the compounds PsG, PsP, PsQ, PsS, PsT, PsU, 3-O-acetyl-PsU, seco-PsJ, seco-PsK and IMNGD. For the cytotoxic profiles, all compounds evaluated showed moderate and non-selective activity against both tumor and normal cell lines, where PsQ and PsG were the most active compounds (GI50 values between 5.8 μM to 12.0 μM). With respect to their anti-microbial activity the compounds showed good and selective activity against the Gram-positive bacteria, while they did not show activity against the Gram-negative bacterium or yeast. PsU, PsQ, PsS, seco-PsK and PsG were the most active compounds (IC50 2.9–4.5 μM) against S. aureus and PsG, PsU and seco-PsK showed good activity (IC50 3.1–3.8 μM) against E. faecalis, comparable to the reference drug vancomycin (4.2 μM)

Discovery of a New Natural Product and a Deactivation of a Quorum Sensing System by Culturing a “Producer” Bacterium With a Heat-Killed “Inducer” Culture

Herein we describe a modified bacterial culture methodology as a tool to discover new natural products via supplementing actinomycete fermentation media with autoclaved cultures of “inducer” microbes. Using seven actinomycetes and four inducer microbes, we detected 28 metabolites that were induced in UHPLC-HRESIMS-based analysis of bacterial fermentations. Metabolomic analysis indicated that each inducer elicited a unique response from the actinomycetes and that some chemical responses were specific to each inducer-producer combination. Among these 28 metabolites, hydrazidomycin D, a new hydrazide-containing natural product was isolated from the pair Streptomyces sp. RKBH-B178 and Mycobacterium smegmatis. This result validated the effectiveness of the strategy in discovering new natural products. From the same set of induced metabolites, an in-depth investigation of a fermentation of Streptomyces sp. RKBH-B178 and autoclaved Pseudomonas aeruginosa led to the discovery of a glucuronidated analog of the pseudomonas quinolone signal (PQS). We demonstrated that RKBH-B178 is able to biotransform the P. aeruginosa quorum sensing molecules, 2-heptyl-4-quinolone (HHQ), and PQS to form PQS-GlcA. Further, PQS-GlcA was shown to have poor binding affinity to PqsR, the innate receptor of HHQ and PQS

Approach to the Interaction Studies of Aristolochia maxima and the Caterpillars of Butterflies Battus polydamas polydamas and Parides panares erythrus

Most butterflies of the tribe Troidini (Lepidoptera: Papilionidae) sequester aristolochic acids (AA) for their protection. These acids are derived from their host plants -family Aristolochiaceae- upon which they feed on during their larval stages. Using analytical High Performance Liquid Chromatography (HPLC) methods we were able to detect the presence of aristolochic acids I and II both in the young leaves of Aristolochia maxima (Aristolochiaceae) and in the caterpillars of the butterflies Battus polydamas polydamas and Parides panares erythrus (Papilionidae, Papilioninae). Aristolochic acid I was the major constituent found, followed by lesser amounts of Aristoloquic acid II. These results confirm that the host-animal interaction among butterflies of the studied species and A. maxima plants is mediated, by aristolochic acids

Bacterial Communities of the Gorgonian Octocoral Pseudopterogorgia elisabethae

Pseudopterogorgia elisabethae is a common inhabitant of Caribbean reefs and is a well-known source of diterpenes with diverse biological activities. Notably, this octocoral is the sole source of the pseudopterosin family of anti-inflammatory diterpenes and is harvested to supply commercial demand for these metabolites. We have characterized the composition of the bacterial community associated with P. elisabethae collected from Providencia Island, Colombia, using both culture-dependent and culture-independent approaches. Culture-independent analysis revealed that the bacterial communities were composed of eight phyla, of which Proteobacteria was the most abundant. At the class level, bacterial communities were dominated by Gammaproteobacteria (82-87 %). Additionally, operational taxonomic units related to Pseudomonas and Endozoicomonas species were the most abundant phylotypes consistently associated with P. elisabethae colonies. Culture-dependent analysis resulted in the identification of 40 distinct bacteria classified as Bacilli (15), Actinobacteria (12), Gammaproteobacteria (9), Alphaproteobacteria (3), and Betaproteobacteria (1). Only one of the 40 cultured bacteria was closely related to a dominant phylotype detected in the culture-independent study, suggesting that conventional culturing techniques failed to culture the majority of octocoral-associated bacterial diversity. To the best of our knowledge, this is the first characterization of the bacterial diversity associated with P. elisabethae

Discovery of Primarolides A and B from Marine Fungus Asteromyces cruciatus Using Osmotic Stress and Treatment with Suberoylanilide Hydroxamic Acid

Advances in whole-genome sequencing of many fungal species has revealed the presence of numerous &ldquo;silent&rdquo; biosynthetic genes, highlighting their potential to produce a wide variety of natural products. These silent biosynthetic genes are regulated in part by their highly condensed chromatin structure, which can be modified to allow transcription in response to external stimuli. In this study, Asteromyces cruciatus was subjected to both epigenetic modification and osmotic stress to enhance the production of new natural products. This &ldquo;cooperative induction&rdquo; strategy led to the isolation and characterization of two new polyketides from a fermentation of A. cruciatus treated with suberoylanilide hydroxamic acid and sodium chloride. The metabolic profiles of the control and treated samples were assessed using ultra-high performance liquid chromatography high-resolution electrospray ionization mass spectrometry (UHPLC-HRESIMS) metabolomic analysis, highlighting the upregulation of two new polyketides, primarolides A and B. These compounds were purified using reversed-phase flash chromatography followed by high-performance liquid chromatography, and their planar structures were established using NMR spectroscopy