Halenaquinol Blocks Staphylococcal Protein A Anchoring on Cell Wall Surface by Inhibiting Sortase A in .

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (-) were isolated from the marine sponge sp., and their structures were elucidated using spectroscopic techniques and by comparing them to previously reported data.

Retinestatin, a Polyol Polyketide from a Termite Nest-Derived sp.

A new polyol polyketide, named retinestatin (), was obtained and characterized from the culture of a strain, which was isolated from a subterranean nest of the termite Morimoto. The planar structure of was elucidated on the basis of the cumulative analysis of ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance spectroscopic data. The absolute configuration of at 12 chiral centers was successfully assigned by employing a -based configuration analysis in combination with ROESY correlations, a quantum mechanics-based computational approach to calculate NMR chemical shifts, and a 3 min flash esterification by Mosher's reagents followed by NMR analysis.

Tandocyclinones A and B, Ether Bridged -Glycosyl Benz[]anthracenes from an Intertidal Zone sp.

Two new proton-deficient metabolites, tandocyclinones A and B ( and ), were discovered via the chemical profiling of the sp. strain TDH03, which was isolated from a marine sediment sample collected from the intertidal mudflat in Tando Port, the Republic of Korea. The structures of and were elucidated as new ether-bridged -glycosyl benz[]anthracenes by using a combination of spectroscopic analyses of ultraviolet (UV) and mass spectrometry (MS) data, along with nuclear magnetic resonance (NMR) spectra, which were acquired in tetrahydrofuran (THF)- selected after an extensive search for a solvent, resulting in mostly observable exchangeable protons in the H NMR spectrum.

Discovery and Biosynthesis of Cihunamides, Macrocyclic Antibacterial RiPPs with a Unique C-N Linkage Formed by CYP450 Catalysis.

Cihunamides A-D (1-4), novel antibacterial RiPPs, were isolated from volcanic-island-derived Streptomyces sp. The structures of 1-4 were elucidated by H, C, and N NMR, MS, and chemical derivatization; they contain a tetrapeptide core composed of WNIW, cyclized by a unique C-N linkage between two Trp units. Genome mining of the producer strain revealed two biosynthetic genes encoding a cytochrome P450 enzyme and a precursor peptide.

Inhibitory Effects of Nitrogenous Metabolites from a Marine-Derived on Isocitrate Lyase of .

Two nitrogenous metabolites, bacillimide () and bacillapyrrole (), were isolated from the culture broth of the marine-derived actinomycete . Based on the results of combined spectroscopic and chemical analyses, the structure of bacillimide () was determined to be a new cyclopenta[]pyrrole-1,3-dione bearing a methylsulfide group, while the previously reported bacillapyrrole () was fully characterized for the first time as a pyrrole-carboxamide bearing an alkyl sulfoxide side chain. Bacillimide () and bacillapyrrole () exerted moderate (IC = 44.

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).

Lenzimycins A and B, Metabolites With Antibacterial Properties From sp. Associated With the Dung Beetle .

Symbiotic microorganisms associated with insects can produce a wide array of metabolic products, which provide an opportunity for the discovery of useful natural products. Selective isolation of bacterial strains associated with the dung beetle, , identified two strains, of which the antibiotic-producing sp. PTH23 inhibited the growth of sp.

Antibacterial Activity of Chromomycins from a Marine-Derived .

A marine-derived actinomycete ( sp. MBTI36) exhibiting antibacterial activities was investigated in the present study. The strain was identified using genetic techniques.

Sortase A-Inhibitory Coumarins from the Folk Medicinal Plant .

Thirteen coumarins (-), including five new compounds (-), were isolated from the folk medicinal plant . Combined spectroscopic analyses revealed that coumarins - are bis-isoprenylated coumarins with diverse oxidation patterns, while is an enantiomeric di-isoprenylated coumarin. The absolute configurations of the stereogenic centers in the isoprenyl chains were assigned through MTPA and MPA methods, and those of the known compounds triphasiol () and ponciol () were also assigned using similar methods.

Sortase A-Inhibitory Metabolites from a Marine-Derived Fungus sp.

Seven alkaloidal compounds (-) and one polyketide () were isolated from a semisolid rice culture of the marine-derived fungus sp. F452. Structures of the isolated compounds were elucidated based on spectroscopic data and comparisons with previously reported data.

New Peptides from The Marine-Derived Fungi and .

Four new peptides were isolated from the culture broths of the marine-derived fungi and ochraceopetaliformis. Based on the results of chemical and spectroscopic analyses, two compounds ( and ) from were determined to be cyclopentapeptides, while those from ochraceopetaliformis were a structurally-related cyclodepsihexapeptide () and its linear analog (). In addition to the presence of a D-amino acid residue, the almost reversed sequence of peptides in and , relative to those of the and , is notable.