Search Results (3)

Xinghamide A (1), a new nonapeptide, was discovered in Streptomyces xinghaiensis isolated from a halophyte, Suaeda maritima (L.) Dumort. Based on high-resolution mass and NMR spectroscopic data, the planar structure of 1 was established, and, in particular, the sequence of nine amino acids was determined with ROESY and HMBC NMR spectra. The absolute configurations of the α-carbon of each amino acid residue were determined with 1-fluoro-2,4-dinitrophenyl-l-and -d-leucine amide (Marfey’s reagents) and 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate, followed by LC-MS analysis. The anti-inflammatory activity of xinghamide A (1) was evaluated by inhibitory abilities against the nitric oxide (NO) secretion and cyclooxygenase-2 (COX-2) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Full article

Streptomyces fradiae sf106 is a type of actinomycete that can produce abundant secondary metabolites, making it a natural cell factory for drug synthesis. In order to comprehensively understand the genomic profile of Streptomyces fradiae sf106 and its potential for producing secondary metabolites, a combination of several methods was used to perform whole-genome sequencing of sf106. The results showed that sf106 is most closely related to Streptomyces xinghaiensis S187; the average nucleotide identity and average amino acid identity of sf106 and S187 were more than 96%. The genome size of sf106 is approximately 7300 kb, the GC content is greater than 72%, and more than 6700 coding sequences (CDS) were identified. Analysis of mobile genetic elements revealed the presence of a large number of horizontally transferred genes in Streptomyces fradiae sf106, which contribute to microbial diversity. Through antiSMASH prediction, 22 secondary metabolite gene clusters were obtained, which had great potential to generate polyketide metabolites. By examining the data, it was found that the genes contained in cluster 9 were similar to those involved in tylosin synthesis. Non-targeted metabolome sequencing revealed that a total of 1855 identifiable metabolites were produced in the fermentation broth, and the majority of metabolites showed highly significant differences in mean relative abundance between the groups. The identified metabolites were compared against the KEGG compound database to obtain metabolite classifications, mainly including Biological Roles, Phytochemical Compounds, Lipids, and Pesticides. One-way ANOVA indicated that the relative concentration of tylosin differed significantly across all the growth periods, except for the late-logarithmic and stabilization stages. This study provides important basic information on the secondary metabolite research of sf106, which will help us to understand and apply Streptomyces fradiae sf106 more comprehensively. Full article

The deep-sea constitutes a true unexplored frontier and a potential source of innovative drug scaffolds. Here, we present the genome sequence of two novel marine actinobacterial strains, MA3_2.13 and S07_1.15, isolated from deep-sea samples (sediments and sponge) and collected at Madeira archipelago (NE Atlantic Ocean; Portugal). The de novo assembly of both genomes was achieved using a hybrid strategy that combines short-reads (Illumina) and long-reads (PacBio) sequencing data. Phylogenetic analyses showed that strain MA3_2.13 is a new species of the Streptomyces genus, whereas strain S07_1.15 is closely related to the type strain of Streptomyces xinghaiensis. In silico analysis revealed that the total length of predicted biosynthetic gene clusters (BGCs) accounted for a high percentage of the MA3_2.13 genome, with several potential new metabolites identified. Strain S07_1.15 had, with a few exceptions, a predicted metabolic profile similar to S. xinghaiensis. In this work, we implemented a straightforward approach for generating high-quality genomes of new bacterial isolates and analyse in silico their potential to produce novel NPs. The inclusion of these in silico dereplication steps allows to minimize the rediscovery rates of traditional natural products screening methodologies and expedite the drug discovery process. Full article