Natural antifoulants from the marine cyanobacterium Lyngbya majuscula

Abstract

Filamentous benthic marine cyanobacteria are a prolific source of structurally unique bioactive secondary metabolites. A total of 12 secondary metabolites, belonging to the mixed polyketide-polypeptide structural class, were isolated from the marine cyanobacterium, Lyngbya majuscula, and were tested to determine if they showed activity against barnacle larval settlement. The assays revealed four compounds, dolastatin 16, hantupeptin C, majusculamide A, and isomalyngamide A, that showed moderate to potent anti-larval settlement activities, with EC(50) values ranging from 0.003 to 10.6 microg ml(-1). In addition, field testing conducted over a period of 28 days (using the modified Phytagel method) based on the cyanobacterial compound, dolastatin 16, showed significantly reduced barnacle settlement as compared to controls at all the concentrations tested. The results of this study highlight the importance of marine cyanobacteria as an underexplored source of potential environmentally friendly antifoulants.

Digitizing mass spectrometry data to explore the chemical diversity and distribution of marine cyanobacteria and algae

“…Examples of marine cyanobacterial natural products that are under investigation for anticancer applications include the cyclodepsipeptides apratoxin A and F, the nitrogen-containing lipid curacin A and the lipopeptides dolastatin 10 and carmaphycin B (Bai et al, 1990; Blokhin et al, 1995; Luesch et al, 2001a, 2001b; Pereira et al, 2012; Tidgewell et al, 2010). These natural product templates have inspired the synthesis of lead compounds using medicinal chemistry approaches, and have resulted in one clinically approved drug (Brentuximab vedotin) for the treatment of cancer; several others are in various stages of clinical and preclinical evaluation (Gerwick and Moore, 2012; Luesch et al, 2001a; 2001b; Tan et al, 2010; Tidgewell et al, 2010; Uzair et al, 2012). Unfortunately, such fruitful natural product materials, rich with so much unexplored potential, oftentimes disappear upon completion of academic careers and closing of laboratories.…”

Isolation and Antimacrofouling Activity of Indole and Furoquinoline Alkaloids from ‘Guatambú’ Trees (Aspidosperma australe and Balfourodendron riedelianum)

“…Marine benthic organisms are constantly exposed to colonization by other organisms such as bacterial communities and invertebrate larvae. Some of these organisms have developed various strategies to counteract the settlement of fouling organisms, such as the production of antifouling chemicals and/or physical defenses . A variety of natural products with antifouling activity have been isolated from marine organisms, including marine bacteria, algae, seagrasses and marine invertebrates .…”

Detection of Bioactive Exometabolites Produced by the Filamentous Marine Cyanobacterium Geitlerinema sp.

“…Marine microorganisms are proving to be promising new sources of a huge number of biologically active products of commercial interest in the pharmaceutical, agricultural and food industries (Tan 2007; Tan et al 2010; Le Gal and Muller-Feuga 1998; Debbab et al 2010). Apart from original products, they produce a wide variety of secondary metabolites that cannot be produced by terrestrial microorganisms (Liu et al 2008).…”

“…Although cyanobacterial metabolites are accumulated mostly in the cyanobacterial biomass, some of them are excreted into the environment (Kreitlow et al 1999; Tan et al 2010). The compounds with biotic properties are typically excreted into the growth media as it was reported for the phenolic compound 4,4′-dihydroxybiphenyl and the indole alkaloid norharmane (9H-pyrido(3,4-b)indole) from the filamentous cyanobacteria Nostoc insulare and Nodularia harveyana , respectively (Volk and Furkert 2006), both belonging to the order Nostocales .…”

“…Another indole alkaloid containing a β-carboline skeleton —harmane (1-methyl-9H-pyrido(3,4-b)indole)—was isolated from the algicidal bacterium Pseudomonas sp. K44-1 by Kodani et al (2002) and the tunicate-associated bacterium Enterococcus faecium from a marine bacterium (Aassila et al 2003), but not from cyanobacteria (Okunade et al 2007; Tan et al 2010). The structures of these compounds are presented in Fig.…”