Configurational assignments of type-I polyketide synthase (PKS)-derived natural products based on spectroscopic and chemical analysis: methodologies and case studies.

Covering: 1992 to 2024Type-I polyketide synthase (PKS)-derived metabolites are structurally diverse bioactive natural products containing multiple stereogenic centres. This review focuses on the configurational analysis of type-I PKS-derived natural products, emphasizing the methodologies and challenges associated with determining their stereochemistry due to their complex structures with multiple chiral centres. Key strategies include -based configuration analysis (JBCA), chemical derivatizations with chiral reagents, degradation methods, NMR spectroscopic analysis, and the exploitation of chiroptical properties.

The safety and efficacy of Sotn ureteroscopy for renal and upper ureteral calculi: a prospective multicenter randomized controlled trial.

Background: Sotn ureteroscopy is a new lithotripsy procedure developed on the basis of ureteroscopy and includes a rigid ureteral access sheath, standard mirror, lithotripsy mirror, and Sotn perfusion aspirator. Thus, we performed a prospective multicenter randomized controlled trial comparing the safety and efficacy of Sotn ureteroscopy in the treatment of renal and upper ureteral calculi.

Methods: In this study, 224 patients with renal and upper ureteral calculi were randomly divided equally into study and control groups from March 2018 to March 2022.

Serratiomycins D1-D3, Antibacterial Cyclic Peptides from a sp. and Structure Revision of Serratiomycin.

Serratiomycin () is an antibacterial cyclic depsipeptide, first discovered from a culture in 1998. This compound was initially reported to contain l-Leu, l-Ser, l--Thr, d-Phe, d-Ile, and hydroxydecanoic acid. In the present study, and three new derivatives, serratiomycin D1-D3 (-), were isolated from a sp.

Glycosylated and Succinylated Macrocyclic Lactones with Amyloid-β-Aggregation-Regulating Activity from a Marine sp.

Two new glycosylated and succinylated macrocyclic lactones, succinyl glyco-oxydifficidin () and succinyl macrolactin O (), were isolated from a strain collected from an intertidal mudflat on Anmyeon Island in Korea. The planar structures of and were proposed using mass spectrometric analysis and NMR spectroscopic data. The absolute configurations of and were determined by optical rotation, -based configuration analysis, chemical derivatizations, including the modified Mosher's method, and quantum-mechanics-based calculation.

Ohmyungsamycin promotes M1-like inflammatory responses to enhance host defence against infections.

Ohmyungsamycin A (OMS) is a newly identified cyclic peptide that exerts antimicrobial effects against . However, its role in nontuberculous mycobacteria (NTMs) infections has not been clarified. (Mabc) is a rapidly growing NTM that has emerged as a human pathogen in both immunocompetent and immunosuppressed individuals.

Targeted Discovery of an Enediyne-Derived Cycloaromatized Compound, Jejucarboside A, from a Marine Actinomycete.

A genomic and spectroscopic signature-based search revealed a cycloaromatized enediyne, jejucarboside A (), from a marine actinomycete strain. The structure of was determined as a new cyclopenta[]indene glycoside bearing carbonate functionality by nuclear magnetic resonance, high-resolution mass spectrometry (MS), MS/MS, infrared spectroscopy, and a modified Mosher's method. An iterative enediyne synthase pathway has been proposed for the putative biosynthesis of by genomic analysis.

Taeanamides A and B, Nonribosomal Lipo-Decapeptides Isolated from an Intertidal-Mudflat-Derived sp.

Two new lipo-decapeptides, namely taeanamides A and B ( and ), were discovered from the Gram-positive bacterium sp. AMD43, which was isolated from a mudflat sample from Anmyeondo, Korea. The exact molecular masses of and were revealed by high-resolution mass spectrometry, and the planar structures of and were elucidated using NMR spectroscopy.

Nyuzenamide C, an Antiangiogenic Epoxy Cinnamic Acid-Containing Bicyclic Peptide from a Riverine sp.

A new nonribosomal peptide, nyuzenamide C (), was discovered from riverine sediment-derived sp. DM14. Comprehensive analysis of the spectroscopic data of nyuzenamide C () revealed that has a bicyclic backbone composed of six common amino acid residues (Asn, Leu, Pro, Gly, Val, and Thr) and four nonproteinogenic amino acid units, including hydroxyglycine, β-hydroxyphenylalanine, -hydroxyphenylglycine, and 3,β-dihydroxytyrosine, along with 1,2-epoxypropyl cinnamic acid.

Gwanakosides A and B, 6-Deoxy-α-l-talopyranose-Bearing Aromatic Metabolites from a sp. and Coculture with sp.

Single-strain cultivation of a mountain soil-derived sp. GA02 and its coculture with sp. GA02N produced two aromatic products, gwanakosides A and B ( and , respectively).

Antitumor Activity of Pulvomycin via Targeting Activated-STAT3 Signaling in Docetaxel-Resistant Triple-Negative Breast Cancer Cells.

Although docetaxel-based regimens are common and effective for early-stage triple-negative breast cancer (TNBC) treatment, acquired drug resistance frequently occurs. Therefore, a novel therapeutic strategy for docetaxel-resistant TNBC is urgently required. Signal transducer and activator of transcription 3 (STAT3) plays a pivotal role in the tumorigenesis and metastasis of numerous cancers, and STAT3 signaling is aberrantly activated in TNBC cells.

Dumulmycin, an Antitubercular Bicyclic Macrolide from a Riverine Sediment-Derived sp.

Dumulmycin () was isolated from sp. DM28, a bacterial strain from a riverine sediment sample. The structure of was elucidated as a bicyclic macrolide possessing 19-membered and 5-membered rings by spectroscopic analysis.

Circ_101341 Deteriorates the Progression of Clear Cell Renal Cell Carcinoma Through the miR- 411/EGLN3 Axis.

Background: Clear cell renal cell carcinoma (ccRCC) is one of the main subtypes of renal cell carcinoma, with intense aggressiveness. The involvement of circular RNAs (circRNAs) in human cancers attracts much concern. The intention of this study was to investigate the expression of circ_101341 and explore its function in ccRCC.

Structures and Biosynthetic Pathway of Pulvomycins B-D: 22-Membered Macrolides from an Estuarine sp.

Pulvomycins B-D (-) were discovered from an estuarine strain along with the known pulvomycin (). The 22-membered macrocyclic lactone structures of - were determined based on the interpretation of NMR, UV, and MS data, the modified Mosher's method, and Kishi's bidentate chiral solvent NMR spectroscopy. Genomic analysis of the bacterial strain revealed the biosynthetic gene cluster of pulvomycin and enabled us to propose the -acyltransferase polyketide biosynthetic pathway.

Rifamycin O, An Alternative Anti- Agent.

is the most difficult-to-treat nontuberculous mycobacteria because of its resistance to many antibiotics. In this study, we screened the Korea Chemical Bank library for a bioluminescent reporter assay to identify molecules capable of acting against On application of the assay, rifamycin O showed excellent in vitro activity with a narrow range of the minimum inhibitory concentration required to inhibit the growth of 90% of the bacterium (MIC = 4.0-6.

Characterization of the Ohmyungsamycin Biosynthetic Pathway and Generation of Derivatives with Improved Antituberculosis Activity.

The cyclic depsipeptides ohmyungsamycin (OMS) A () and B (), isolated from the marine-derived sp. SNJ042, contain two non-proteinogenic amino acid residues, -hydroxy-l-phenylalanine (-hydroxy-l-Phe) and 4-methoxy-l-tryptophan (4-methoxy-l-Trp). Draft genome sequencing of sp.