Differences in the content of purple pigments, catechinopyranocyanidins A and B, in various adzuki beans, Vigna angularis.

Catechinopyranocyanidins A and B (cpcA, B) are purple pigments isolated from the seed coat of the small red bean called adzuki in Japanese (Vigna angularis). CpcA and B are known to be responsible for the purple color of an-paste. The quality evaluation of the paste is based on its purple color; therefore, it is important to analyze the contents of cpcA and B in various azuki beans, which differ in the cultivar, production area, and cultivation conditions. The extraction of cpcA and B from dried beans was conducted, followed by high-performance liquid chromatography analysis. The content of cpcA and B in various cultivars from Japan, Korea, China, and Nepal was quantified. The cpcA and B content was the highest in the regular adzuki cultivar from Hokkaido Prefecture (Japan), and that of the beans from Korea and China was low. The content of the pale-colored beans from Nepal was the lowest.

The second Phytophthora mating hormone defines interspecies biosynthetic crosstalk.

The heterothallic species of the agricultural pest Phytophthora use mating hormones α1 and α2 to regulate their sexual reproduction. Here we describe the absolute stereostructure of the second mating hormone α2 as defined by spectroscopic analysis and total synthesis. We have uncovered not only the interspecies universality of α hormones but also the pathway by which α2 is biosynthesized from phytol by A2-mating type strains and metabolized to α1 by A1 strains.

Synthesis and absolute configuration of hormone alpha1.

An important biological event in phytopathogens of the genus Phytophthora is sexual reproduction, which is conducted by two mating types, A1 and A2. A factor known as hormone alpha1 is secreted by the A1 mating type and induces the formation of sexual spores (oospores) in the A2 mating type. Here we describe the asymmetric synthesis and assignment of the absolute configuration of hormone alpha1 by oospore-inducing assays of the synthesized isomers.

Characterization of a Phytophthora mating hormone.

Water molds of the genus Phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in Phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a Phytophthora mating hormone, a1, which was obtained from approximately 2 tons of culture fluid of one mating type of a species and which induced sexual spores on the counter-mating type at a nanogram level.