RESUMEN
UNLABELLED: The study aimed to discover quorum sensing (QS) inhibitors from marine sponge-derived actinomycetes and analyse its inhibitory activities against QS-mediated virulence factors in Pseudomonas aeruginosa. Seventy-two actinomycetes isolated from marine invertebrates collected from the western coast of India were screened against the QS indicator strain Chromobacterium violaceum CV12472. Methanol extracts of 12 actinomycetes showing inhibition of violacein production were accessed for downregulation of QS-mediated virulence factors like swarming, biofilm formation, pyocyanin, rhamnolipid and LasA production in Ps. aeruginosa ATCC 27853. The isolates NIO 10068, NIO 10058 and NIO 10090 exhibited very good anti-QS activity, with NIO 10068 being the most promising one. Mass spectrometric analysis of NIO 10068 methanol extract revealed the presence of cinnamic acid and linear dipeptides proline-glycine and N-amido-α-proline in the active extract. Detailed investigation suggested that although linear dipeptide Pro-Gly is to some extent responsible for the observed biological activity, cinnamic acid seems to be the main compound responsible for it. Marine-derived actinomycetes are a potential storehouse for QS inhibitors. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report not only on marine sponge-associated Streptomyces for anti-QS in Ps. aeruginosa but also on cinnamic acid and proline-derived linear dipeptides proline-glycine as QS inhibitors. The results reveal that marine-derived actinomycetes may not only play a role in the defensive mechanism of their host but also lead to new molecules useful in the development of novel antivirulence drugs.
Asunto(s)
Invertebrados/microbiología , Pseudomonas aeruginosa/patogenicidad , Percepción de Quorum , Streptomyces/química , Streptomyces/fisiología , Animales , Chromobacterium/metabolismo , Cinamatos/análisis , Cinamatos/farmacología , Dipéptidos/análisis , Dipéptidos/farmacología , India , Indoles/metabolismo , Interacciones Microbianas , Pseudomonas aeruginosa/crecimiento & desarrollo , Pseudomonas aeruginosa/fisiología , Piocianina/biosíntesis , Percepción de Quorum/efectos de los fármacos , Streptomyces/clasificación , Streptomyces/aislamiento & purificación , Virulencia , Factores de Virulencia/metabolismoRESUMEN
The fatty acid compositions of three psychrophilic species of Bacillus were determined by gas--liquid chromatography. The proportions of straight-chain fatty acids, branched-chain fatty acids, and unsaturated fatty acids were found to be 13.3, 86.7, and 26.1% of the total cellular fatty acids for Bacillus globispores, 36.6, 63.4, and 25.1% for Bacillus insolitus, and 6.9, 93.1, and 18.4% for Bacillus psychrophilus, respectively. In all three organisms the de novo fatty acid synthetase specificity towards acyl-CoA primers was butyryl-CoA greater than propionyl-CoA much greater than acetyl-CoA. This shows that B. insolitus, which has an unusually large proportion of straight-chain fatty acids for Bacillus, does not possess a different de novo fatty acid synthetase than the other two organisms. Therefore, the greater proportion of straight-chain fatty acids in B. insolitus may be explained by a large supply of straight-chain primer.
Asunto(s)
Bacillus/enzimología , Ácido Graso Sintasas/análisis , Ácidos Grasos/análisis , Acilcoenzima A/metabolismo , Ácidos Grasos/biosíntesis , Malonil Coenzima A/metabolismoRESUMEN
A female patient suffering from donovanosis of the oral cavity without associated lesions elsewhere is reported. The importance of remembering donovanosis in the differential diagnosis of chronic granulomatous ulceration of the mouth is emphasized.