抄録
Aversion was named by Cayley (1923) to the mutual inhibition of mycelial growth by the growing colonies of different strains of the same fungal species. We investigated, as the second example of aversion, the aversion factor as well as new metabolites produced by Cochliobolus lunata, as mentioned in this report. Of the ten IFO strains of the fungus tested, only one strain (IFO 5997) produced aversion factor which inhibited the growth of other eight strains. Aversion factor, named lunatoic acid A, was isolated and its absolute stereochemistry was established as shown in 1. Lunatoic acid B, a closely related metabolite of the 5997 strain, was determined to have the antipodal stereochemistry at C -7 position, as 2. 1 inhibited the growth of other strains at 3-12ppm, and the 5997 itself at 100ppm. Interestingly, the mycelia suppressed by 1 produced chlamydospore-like cells, which were shown to be viable by germinating and growing back to the normal mycelia, when the fungus was transferred to the new medium. Thus, 1 was shown to be a new type of morphogenesis-inducing substance of fungi. New metabolites, named zeaenol and lunatinin, were isolated from the 5997 by changing the culture media, and their structures were elucidated as 8 and 14, respectively. Metabolites produced by other strains were also investigated. As the results, two new metabolites, i.e., radicinol and α-acetylorcinol, were isolated, being elucidated as 18 and 21, respectively, accompanied with known metabolites such as α-resorcylic acid, p-hydroxyphenylethylalcohol and radicinin, the absolute stereochemistry of the last one was also established in this report.
