Spirohexalines, new inhibitors of bacterial undecaprenyl pyrophosphate synthase, produced by Penicillium brasilianum FKI-3368.

An enzyme assay for bacterial undecaprenyl pyrophosphate (UPP) synthase was performed to screen microbial culture broths for inhibitors of UPP synthase. During the course of this screening program, an EtOH extract of a rice culture of Penicillium brasilianum FKI-3368 was found to inhibit UPP synthase activity. From activity-guided purification, a new compound-designated spirohexaline was isolated together with the structurally related and known viridicatumtoxin by ethyl acetate extraction silica gel and octadecylsilane column chromatographies and high-performance liquid chromatography.

Spin probe study on the interaction of chitosan-derived polymer surfactants with lipid membrane.

Chitosan-derived polymer surfactants, sulfated N-acyl-chitosan (S-Cn-Chitosan), were synthesized and compared with commonly used low-molecular-weight surfactants, sodium dodecyl sulfate (SDS), dodecyltrimethyl ammonium chloride (DTAC), and octaethyleneglycol mono n-dodecyl ether (BL8SY), in their interaction with a lipid membrane using a spin probe method. A suspension of dipalmitoylphosphatidyl-choline (DPPC) spin-labeled strongly (10%) with a spin probe, 1-palmitoyl-2-(12-doxyl) stearoyl-phosphatidylcholine, was mixed with the surfactant solutions. The dissolution time of the DPPC membrane was estimated from the peak height change vs time, which was caused by the decrease in spin-exchange interaction.