TolCV1 inhibition by NPPB renders less virulent and more susceptible to antibiotics.

Bacterial efflux pumps play important roles in the antibiotic resistance and excretion of virulence factors. We previously characterized that TolCV1, a component of efflux pumps, plays critical roles in resistance to antibiotics and bile and also RtxA1 toxin secretion of . In this context, we speculated that TolCV1 blockers would have a dual effect of enhancing susceptibility to antibiotics and suppressing virulence of .

Chromatographic Determination of the Absolute Configuration in Sanjoinine A That Increases Nitric Oxide Production.

A chiral derivatization strategy with phenylglycine methyl ester (PGME) was employed to develop a straightforward method to determine the absolute configurations of ,-dimethyl amino acids. The PGME derivatives were analyzed using liquid chromatography-mass spectrometry to identify the absolute configurations of various ,-dimethyl amino acids based on their elution time and order. The established method was applied to assign the absolute configuration of the ,-dimethyl phenylalanine in sanjoinine A (), a cyclopeptide alkaloid isolated from Zizyphi Spinosi Semen widely used as herbal medicine for insomnia.

Actinoflavosides B-D, Flavonoid Type Glycosides from Tidal Mudflat-Derived Actinomyces.

Three new secondary metabolites, actinoflavosides B-D (-), were discovered in the culture broth of two actinomycete strains (JML48 and JMS33) that were isolated from tidal mudflat sediment in Muan, Republic of Korea. The planar structures of the actinoflavosides were elucidated by MS, UV, and NMR analyses. The stereochemistry of an aminosugar, 2,3,6-trideoxy-3-amino-ribopyranoside in the actinoflavosides was determined by -based configuration analysis using values obtained from DQF-COSY experiments and modified Mosher's method.