Metabolites from an Antarctic Sponge-Associated Bacterium, Pseudomonas aeruginosa

Abstract

In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms. A series of diketopiperazines (1-6) including a new natural product (6) and two known phenazine alkaloid antibiotics (7 and 8) were isolated from the culture broth of this bacterium.

Purification and identification of two antifungal cyclic dipeptides from Bacillus cereus subsp. thuringiensis associated with a rhabditid entomopathogenic nematode especially against Fusarium oxysporum

“…Cyclo-(L-Pro-L-Met) was first reported from Antarctic sponge-associated bacterium, P. aeruginosa 47 and marine-derived actinomycete, Nocardiopsis sp. 03N67 48 .…”

“…The reaction mixture was heated at 47 C for 1 h, cooled to room temperature, and then acidified with 2.0 M HCl (20 ml). In a similar fashion, standard D-and L-amino acids were derivatized separately.…”

6-Hydroxymethyl-1-phenazine-carboxamide and 1,6-phenazinedimethanol from a marine bacterium, Brevibacterium sp. KMD 003, associated with marine purple vase sponge

“…27 Compounds 1 and 2 showed antimicrobial activity toward three human pathogenic microorganisms (MIC 50 ¼20 mM against B. subtilis, 5 mM against E. hirae and 5 mM against M. luteus). In previously reported literature, 23 the structural neighbors of compound 1, PCA and PCN, efficiently inhibited the growth of Bacillus cereus (MIC o2 mM), whereas showed only modest antimicrobial activity against M. luteus (MIC 20 mM). Compounds 1 and 2 were only weakly cytotoxic against eukaryotic cell lines with an IC 50 value 205.8 and 174.3 mM on HL-60 human leukemia cell lines, respectively, whereas showed no cytotoxicity against five human solid tumor cell lines.…”

“…Although compounds 1 and 2 seem quite simple, small modifications of the core phenazine structure give rise to a dynamic change of color, redox potential and solubility. 16 Moreover, phenazine-1-carboxamide (PCN) and phenazine-1-carboxylic acid (PCA), the structural neighbors of 6-hydroxymethyl-1-phenazinecarboxylic acid (1), have important physiological roles, including Fe acquisition, 22 and contribute to pathogen inhibition 23 and microbial biofilm formation. 24 Compound 1 is composed of two functionalities, a hydroxymethyl and a carboxamide, whereas compound 2 includes two hydroxymethyl functionalities, the first examples of these structural compositions.…”

“…tritici and Pythium spp., 25 and PCN displayed antimicrobial activity especially against plant pathogenic Gram-positive bacteria and fungi. 23 PCN is synthesized in Pseudomonas aeruginosa by the conversion of PCA in the pyocyanin biosynthetic pathway, which consists of two core loci responsible for the synthesis of PCA and three additional genes encoding unique enzymes involved in the conversion of PCA to pyocyanin, 1-hydroxyphenazine and PCN. 26 In addition, PCN has important physiological roles, including Fe acquisition, due to its redox-activity like other phenazines such as pyocyanin, PCA and 1-hydroxyphenazine inter alia.…”