Next Article in Journal
The Transcriptome of Bathymodiolus azoricus Gill Reveals Expression of Genes from Endosymbionts and Free-Living Deep-Sea Bacteria
Next Article in Special Issue
Ammonificins C and D, Hydroxyethylamine Chromene Derivatives from a Cultured Marine Hydrothermal Vent Bacterium, Thermovibrio ammonificans
Previous Article in Journal
Gene Sequence Based Clustering Assists in Dereplication of Pseudoalteromonas luteoviolacea Strains with Identical Inhibitory Activity and Antibiotic Production
Mar. Drugs 2012, 10(8), 1741-1764; doi:10.3390/md10081741
Article

Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role

1,* , 2
, 1
, 3
, 3
, 4
, 2
 and 1
Received: 29 June 2012; in revised form: 1 August 2012 / Accepted: 8 August 2012 / Published: 20 August 2012
(This article belongs to the Special Issue Deep-Sea Natural Products)
View Full-Text   |   Download PDF [997 KB, uploaded 20 August 2012]   |   Browse Figures
Abstract: Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of colonial Antarctic ascidians from deep-water collections belonging to the genera Aplidium and Synoicum to evaluate the incidence of organic deterrents and their variability. The ether fractions from 15 samples including specimens of the species A. falklandicum, A. fuegiense, A. meridianum, A. millari and S. adareanum were subjected to feeding assays towards two relevant sympatric predators: the starfish Odontaster validus, and the amphipod Cheirimedon femoratus. All samples revealed repellency. Nonetheless, some colonies concentrated defensive chemicals in internal body-regions rather than in the tunic. Four ascidian-derived meroterpenoids, rossinones B and the three derivatives 2,3-epoxy-rossinone B, 3-epi-rossinone B, 5,6-epoxy-rossinone B, and the indole alkaloids meridianins A–G, along with other minoritary meridianin compounds were isolated from several samples. Some purified metabolites were tested in feeding assays exhibiting potent unpalatabilities, thus revealing their role in predation avoidance. Ascidian extracts and purified compound-fractions were further assessed in antibacterial tests against a marine Antarctic bacterium. Only the meridianins showed inhibition activity, demonstrating a multifunctional defensive role. According to their occurrence in nature and within our colonial specimens, the possible origin of both types of metabolites is discussed.
Keywords: Antarctic colonial tunicates; deterrent activity; sea star Odontaster validus; amphipod Cheirimedon femoratus; antibacterial activity Antarctic colonial tunicates; deterrent activity; sea star Odontaster validus; amphipod Cheirimedon femoratus; antibacterial activity
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Export to BibTeX |
EndNote


MDPI and ACS Style

Núñez-Pons, L.; Carbone, M.; Vázquez, J.; Rodríguez, J.; Nieto, R.M.; Varela, M.M.; Gavagnin, M.; Avila, C. Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role. Mar. Drugs 2012, 10, 1741-1764.

AMA Style

Núñez-Pons L, Carbone M, Vázquez J, Rodríguez J, Nieto RM, Varela MM, Gavagnin M, Avila C. Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role. Marine Drugs. 2012; 10(8):1741-1764.

Chicago/Turabian Style

Núñez-Pons, Laura; Carbone, Marianna; Vázquez, Jennifer; Rodríguez, Jaime; Nieto, Rosa María; Varela, María Mercedes; Gavagnin, Margherita; Avila, Conxita. 2012. "Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role." Mar. Drugs 10, no. 8: 1741-1764.


Mar. Drugs EISSN 1660-3397 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert