Novelnonribosomal peptide synthetase (NRPS)genes sequenced from intertidal mudflat bacteria

Abstract

Nonribosomal peptide synthetases (NRPS) are actively sought out, due to pharmacologically important activities of their metabolites. In marine environment, the most prevalent nonribosomal peptide antibiotic producers are sponges inhabiting microorganisms. Conversely, strains from marine sediments and more especially from intertidal mudflats have not been extensively screened for the presence of new NRPS. In this study, for the first time, a collection of one hundred intertidal mudflat bacterial isolates (Marennes-Oléron Bay, France) was assessed for (1) the presence of NRPS genes by degenerated PCR targeting conserved adenylation domains and (2) for their production of antimicrobial molecules. (1) Bacteria with adenylation domains (14 strains) were identified by 16S rRNA gene sequence analysis and grouped into Firmicutes (one strain) and Proteobacteria (13 strains). In silico analysis of the NRPS amino acid sequences (n = 7) showed 41-58% ID with sequences found in the NCBI database. Three new putative adenylation domain signatures were found. (2) The culture supernatant of one of these strains, identified as a Bacillus, was shown to strongly inhibit the growth of Staphylococcus aureus, S. epidermidis, and Enterococcus faecalis. This study portends that the intertidal mudflat niche could be of interest for the discovery of new NRPS genes and antimicrobial producing strains.

Identification of a novel endophytic Bacillus sp. from Capsicum annuum with highly efficient and broad spectrum plant probiotic effect

“…(Tambadou et al . ). They synthesize bioactive peptides by thiotemplate assembly mechanism in a modular manner in which each module is executing a significant task.…”

“…Nonribosomal peptide synthases (NRPS) are important group of enzymes which are responsible for the biosynthesis of well known secondary metabolites like penicillin, vancomycin, siderophores, cyanotoxins, biosurfactants, immunosuppressants, anticancer agents, anti-inflammatory agents etc. (Tambadou et al 2014). They synthesize bioactive peptides by thiotemplate assembly mechanism in a modular manner in which each module is executing a significant task.…”

Intertidal marine sediment harbours Actinobacteria with promising bioactive and biosynthetic potential

“…Intertidal areas, which endure regular periods of immersion and emersion, are important in the coastal or estuarine environment and represent an underexplored biological niche that could be of interest for the discovery of novel biosynthetic genes and antimicrobials producing strains 36 . Diu (20.71°N 70.98°E) is a small island in the Arabian Sea near the Saurashtra Peninsula of Gujarat (India) covering an area of 38.8 km 2 .…”

Investigating the Biosynthesis of Natural Products from Marine Proteobacteria: A Survey of Molecules and Strategies

“…PKS pathways are analogous to NRPS pathways; beta keto acid building blocks are selected by acyltransferase (AT) domains, tethered to acyl carrier protein (ACP) domains, and added to the growing molecules by a Claisen condensation catalyzed by ketosynthase (KS) domains. As marine bacteria are investigated more thoroughly as alternative sources of novel natural products [ 14 , 15 , 16 , 17 , 18 ], the molecular scaffolds and biosynthetic mechanisms observed for marine NRPS and PKS pathways appear to deviate significantly from those found in terrestrial bacteria [ 19 , 20 ]. It appears that marine bacteria may display a greater diversity/frequency of non-canonical biosynthetic mechanisms, particularly through non-linear or iterative NRPS activity when compared to terrestrial microorganisms, additionally a greater number of halogenated natural products have been identified from marine sources likely due to the higher concentration of halides in seawater compared to soil [ 21 , 22 , 23 ].…”