Meroterpenoids are hybrid natural products of both terpenoid and polyketide origin. We identified a biosynthetic gene cluster that is responsible for the production of the meroterpenoid pyripyropene in the fungus Aspergillus fumigatus through reconstituted biosynthesis of up to five steps in a heterologous fungal expression system. The cluster revealed a previously unknown terpene cyclase with an unusual sequence and protein primary structure. The wide occurrence of this sequence in other meroterpenoid and indole-diterpene biosynthetic gene clusters indicates the involvement of these enzymes in the biosynthesis of various terpenoid-bearing metabolites produced by fungi and bacteria. In addition, a novel polyketide synthase that incorporated nicotinyl-CoA as the starter unit and a prenyltransferase, similar to that in ubiquinone biosynthesis, was found to be involved in the pyripyropene biosynthesis. The successful production of a pyripyropene analogue illustrates the catalytic versatility of these enzymes for the production of novel analogues with useful biological activities.

-permeable, AMPA-GluR explains the selective susceptibility to excitotoxicity of cells at these stages of oligodendroglial differentiation, and is likely to be important to these cells in the trans-synaptic Ca 2+ -signaling from glutamatergic neurons, which occurs in hippocampus in vivo.

A set of single crystals of the layered cobaltite Bi2.3-x PbxSr2.6Co2Oy (0 ≤x≤0.44) were prepared by a flux technique. The resistivity ρ and the thermopower S along the in-plane direction were measured, and the thermoelectric properties were compared with those of other oxides. The Pb substitution causes a decrease in ρ and an increase in S below 100 K, which improves the power factor S 2/ρ by 3–4 times. The transport parameters exhibit an anomaly near 25–50 K, such as a plateau in S and an upturn in ρ, which we ascribe to the reduction of the density of states owing to a pseudogap.

Unexpected methylation: Terretonin is a fungal meroterpenoid derived from 3,5‐dimethylorsellinic acid (DMOA). Trt1 is a terpene cyclase involved in terretonin biosynthesis and only accepts the methylated compound as a substrate to produce the cyclized product. Methylation is a common requirement for the cyclization steps in DMOA‐derived meroterpenoid biosynthesis.

Caspase-3 enzyme activity is induced, and cell death follows, when cerebellar granule neurons (CGNs) from 8-day-old rats are transferred from an extracellular concentration of 25 mM K ϩ (25 mM [K ϩ