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.

Discovery of Terminal Oxazole-Bearing Natural Products by a Targeted Metabologenomic Approach.

A targeted metabologenomic method was developed to selectively discover terminal oxazole-bearing natural products from bacteria. For this, genes encoding oxazole cyclase, a key enzyme in terminal oxazole biosynthesis, were chosen as the genomic signature to screen bacterial strains that may produce oxazole-bearing compounds. Sixteen strains were identified from the screening of a bacterial DNA library (1,000 strains) using oxazole cyclase gene-targeting polymerase chain reaction (PCR) primers.

Anithiactin D, a Phenylthiazole Natural Product from Mudflat-Derived sp., Suppresses Motility of Cancer Cells.

Anithiactin D (), a 2-phenylthiazole class of natural products, was isolated from marine mudflat-derived actinomycetes sp. 10A085. The chemical structure of was elucidated based on the interpretation of NMR and MS data.

Targeted and Logical Discovery of Piperazic Acid-Bearing Natural Products Based on Genomic and Spectroscopic Signatures.

A targeted and logical discovery method was devised for natural products containing piperazic acid (Piz), which is biosynthesized from ornithine by l-ornithine -hydroxylase (KtzI) and - bond formation enzyme (KtzT). Genomic signature-based screening of a bacterial DNA library (2020 strains) using polymerase chain reaction (PCR) primers targeting identified 62 strains (3.1%).

Sadopeptins A and B, Sulfoxide- and Piperidone-Containing Cyclic Heptapeptides with Proteasome Inhibitory Activity from a sp.

New sulfur-bearing natural products, sadopeptins A and B ( and ), were discovered from sp. YNK18 based on a targeted search using the characteristic isotopic signature of sulfur in mass spectrometry analysis. Compounds and were determined to be new cyclic heptapeptides, bearing methionine sulfoxide [Met(O)] and 3-amino-6-hydroxy-2-piperidone (Ahp), based on 1D and 2D NMR spectroscopy along with IR, UV, and MS.

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.

Cyclodimerization of Mohangamide A by Thioesterase Domain Is Directed by Substrates.

Mohangamide A is a pseudo-dimeric nonribosomal peptide biosynthesized along with its monomer, WS9326A, and is expected to be formed by the head-to-tail cyclodimerization of linear WS9326A and another identical peptide chain with a different acyl side chain. experiments with the -acetylcysteamine thioesters of the corresponding monomeric intermediates and thioesterase domains of sp. SNM55 and showed that this cyclodimerization reaction is directed by the substrate structures and occurs only with both linear intermediates.

Discovery and Photoisomerization of New Pyrrolosesquiterpenoids Glaciapyrroles D and E, from Deep-Sea Sediment sp.

Two new pyrrolosesquiterpenes, glaciapyrroles D () and E () were discovered along with the previously reported glaciapyrrole A () from sp. GGS53 strain isolated from deep-sea sediment. This study elucidated the planar structures of and using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), and infrared (IR) spectroscopic data.

Ligiamycins A and B, Decalin-Amino-Maleimides from the Co-Culture of sp. and sp. Isolated from the Marine Wharf Roach, .

sp. GET02.ST and sp.

Saccharobisindole, Neoasterric Methyl Ester, and 7-Chloro-4(1H)-quinolone: Three New Compounds Isolated from the Marine Bacterium sp.

Analysis of the chemical components from the culture broth of the marine bacterium sp. CNQ-490 has yielded three novel compounds: saccharobisindole (), neoasterric methyl ester (), and 7-chloro-4()-quinolone (), in addition to acremonidine E (), pinselin (), penicitrinon A (), and penicitrinon E (). The chemical structures of the three novel compounds were elucidated by the interpretation of 1D, 2D nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS) data.

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).

Antibacterial Meroterpenoids, Merochlorins G-J from the Marine Bacterium sp.

Four new chlorinated meroterpenoids, merochlorins G-J (-), and , a dihydronaphthalenedione precursor, along with known merochlorins A () and C-F (-), were obtained from cultivation of the bacterium strain sp. CNH-189, which was isolated from marine sediment. The planar structures of compounds - and were elucidated by interpretation of MS, UV, and NMR spectroscopic data.

Unprecedented Noncanonical Features of the Nonlinear Nonribosomal Peptide Synthetase Assembly Line for WS9326A Biosynthesis.

Systematic inactivation of nonribosomal peptide synthetase (NRPS) domains and translocation of the thioesterase (TE) domain revealed several unprecedented nonlinear NRPS assembly processes during the biosynthesis of the cyclodepsipeptide WS9326A in Streptomyces sp. SNM55. First, two sets of type ΙΙ TE (TEΙΙ)-like enzymes mediate the shuttling of activated amino acids between two sets of stand-alone adenylation (A)-thiolation (T) didomain modules and an "A-less" condensation (C)-T module with distinctive specificities and flexibilities.

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.

Pentaminomycins C-E: Cyclic Pentapeptides as Autophagy Inducers from a Mealworm Beetle Gut Bacterium.

Pentaminomycins C-E (-) were isolated from the culture of the sp. GG23 strain from the guts of the mealworm beetle, . The structures of the pentaminomycins were determined to be cyclic pentapeptides containing a modified amino acid, -hydroxyarginine, based on 1D and 2D NMR and mass spectroscopic analyses.

Formicolides A and B, Antioxidative and Antiangiogenic 20-Membered Macrolides from a Wood Ant Gut Bacterium.

Two new macrolides, formicolides A () and B (), were isolated from sp. BA01, a gut bacterial strain of the wood ant (). Their 20-membered macrocyclic lactone structures were established using NMR and mass spectrometric data.

Formicins, -Acetylcysteamine-Bearing Indenone Thioesters from a Wood Ant-Associated Bacterium.

Formicins A-C (-) were discovered from sp. associated with wood ants. The structures of and were elucidated as indenone thioesters bearing -acetylcysteamine based on spectroscopic analysis.

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.

Structural Revision of Lydiamycin A by Reinvestigation of the Stereochemistry.

Lydiamycin A () is a previously reported piperazic acid-bearing cyclic peptide from . The absolute configuration of lydiamycin A has not been fully determined despite the fact that multiple total syntheses have been reported. The absolute configuration of was reinvestigated by the advanced Marfey's method, chemical derivatization, and quantum-mechanics-based computational analysis, eventually resulting in a structural revision and establishment of the complete configuration.

Genome-based analysis for the bioactive potential of Streptomyces yeochonensis CN732, an acidophilic filamentous soil actinobacterium.

Background: Acidophilic members of the genus Streptomyces can be a good source for novel secondary metabolites and degradative enzymes of biopolymers. In this study, a genome-based approach on Streptomyces yeochonensis CN732, a representative neutrotolerant acidophilic streptomycete, was employed to examine the biosynthetic as well as enzymatic potential, and also presence of any genetic tools for adaptation in acidic environment.

Results: A high quality draft genome (7.

Structure Revision and the Biosynthetic Pathway of Tripartilactam.

Tripartilactam () is a natural macrocyclic lactam originally reported to have a unique [18,8,4]-tricyclic framework. However, the validity of this structure has been contested since niizalactam C (), bearing a [18,6,6]-tricyclic skeleton, was proposed as an alternative structure in 2015. In the present study, a comprehensive reinvestigation of NMR spectroscopic data and a C-C COSY NMR experiment identified direct C-C coupling, thus leading to the unequivocal revision of the structure of tripartilactam as niizalactam C ().

Resorcinosides A and B, Glycosylated Alkylresorcinols from a Marine-Derived Strain of the Fungus .

Two new glycosylated alkylresorcinols, resorcinosides A () and B (), were isolated from a strain of the fungus derived from a marine sediment sample collected from Cu Lao Cham Island, Vietnam. The structures of and were established by interpretation of 1D and 2D NMR and high-resolution ESIMS data, and their absolute configurations were confirmed by the coupling constant of the anomeric proton, acid hydrolysis, subsequent HPLC analysis, Mosher's method, and quantum-mechanics-based computational analysis of NMR chemical shifts. The structure elucidation indicated that and are new alkylresorcinols with d-glucose, and has an α-pyrone moiety attached to the aromatic ring.

Meroindenon and Merochlorins E and F, Antibacterial Meroterpenoids from a Marine-Derived Sediment Bacterium of the Genus .

Meroterpenoids, meroindenon () and merochlorins E () and F (), were isolated from a marine-derived bacterium belonging to the genus . Their chemical structures were established using extensive analysis of MS, UV, ECD, and NMR spectroscopic data. Compounds - possess a tetrahydroxynaphthalene core and a C-isoprene unit.