College of Pharmacy, Research Institute of Pharmaceutical Sciences, Chonnam National University, Gwangju, South Korea.
Published: May 2022
AI Article Synopsis
Article Abstract
Cystargamides C and D ( and ) were isolated from a marine actinomycete strain collected at Beolgyo, South Korea. The planar structures of the cystargamides were elucidated by 1/2D NMR, UV, and MS spectroscopic analyses. The absolute configurations of and were determined based on ROESY correlations and the advanced Marfey's methods. The structures of the compounds were elucidated as new lipodepsipeptides bearing six amino acids with an epoxy fatty acid side chain. For the first time, the nonribosomal peptide synthetase biosynthetic pathway of the cystargamides has been proposed using whole genome sequence analysis. The cystargamides displayed antioxidant effect in the DPPH and ABTS assay. The discovery of new cyclic lipopeptides, cystargamides C and D, from a tidal mudflat-derived sp. supported that marine bacteria have potential as source of bioactive natural products.
The calcium-dependent antibiotics (CDAs) are a group of seven closely related membrane-active cyclic lipopeptide antibiotics (cLPAs) first isolated in the early 1980s from the fermentation broth of . Their target was unknown, and the mechanism of action is uncertain. Herein, we report new routes for the synthesis of CDA4b and its analogues, explore the structure-activity relationships at its lipid tail and at positions 3, 9, and 11, and determine the CDAs' lipid target.
Introduction: Murepavadin is an antimicrobial peptide (AMP) in clinical development that selectively targets LptD and whose resistance profile remains unknown. We aimed to explore genomic modifications and consequences underlying murepavadin and/or colistin susceptibility.
Methods: To define genomic mechanisms underlying resistance, we performed two approaches: 1) a genome-wide association study (GWAS) in a clinical collection (n=496), considering >0.
New lipodepsipeptides, octaminomycins C and D ( and ), were discovered in an engineered sp. strain overexpressing the LysR transcriptional regulator family. The structures of and were elucidated by comprehensive analysis of their UV, HRMS, and NMR data.
Overexpression of a global transcriptional regulator LaeA was performed to awaken cryptic biosynthetic gene clusters (BGCs) in a marine sponge-derived fungus, Aspergillus niger L14, to obtain secondary metabolites (SMs), and resulted in the production of five previously undiscovered SMs in the wild-type strain, including three cyclic lipopeptides aspochracin (1), JBIR-15 (2) and sclerotiotide C (3), and kojic acid (4) and penicillic acid (5). Bioassays revealed that compound 2 displayed promising antimicrobial effects on Candida albicans with a MIC value of 32 µg/mL and 4 exhibited significant antioxidant activity with the similar IC50 value (5 µg/mL) to that of ascorbic acid. Transcriptome analysis results indicated that the overexpression of LaeA in strain L14 remarkably enhanced the expression of genes involved in polyketide synthase-nonribosomal peptide synthetase (PKS/NRPS) hybrids and amino acid metabolism, demonstrating an effective approach for a production of cyclic lipopeptides.
Spodoptera litura (S. litura) is a polyphagous pest of the family Lepidoptera, which causes damage and yields losses to many crops. The long-term use of chemical pesticides for control not only seriously threatens environmental health, but also causes S.
